Materials Day 2013

1

Table of Contents ______________________________________________________________ Schedule of Events ...................................................................................................................................................1

Keynote Speaker ......................................................................................................................................................3

Invited Speakers .......................................................................................................................................................4

Poster List by Research Category ............................................................................................................................8

Poster List with Abstracts ......................................................................................................................................14

Poster Session Map ................................................................................................................................................48

Schedule of Events _____________________________________________________________ __________________________ Tuesday, October 15, 2013 ___________________________ 10:30 a.m. Registration MSC, 3rd Floor Commons 11:00 a.m. Guided tours MSC, 3rd Floor Commons 12:00 p.m. Lunch on your own 1:00 p.m. – 2:30 p.m. Tools and Tutorials – MSC

Advanced Coatings for Corrosion, Wear, Erosion, and Thermal Protection N-308 A&B for Extreme Environments Doug Wolfe, Penn State, Applied Research Lab Bio-inspired Interfacial Materials: Fundamentals and Applications N-203 A&B Tak-Sing Wong, Penn State, Mechanical Engineering Materials and Additive Manufacturing N-201 A&B Todd Palmer & Rich Martukanitz, Penn State, Applied Research Lab Medical Plastics: Materials and Process Technologies N-050 A&B Greg Dillon, Alicyn Rhoades & Jonathan Meckley, Penn State Erie The Behrend Campus

3:00 p.m. – 4:30 p.m. Tools and Tutorials - MSC

Advances in Materials for Use in Point-of-Care Diagnostics N-201 A&B Scott Phillips, Penn State, Chemistry Introduction to the Materials Characterization Laboratory – N-308 A&B A State-of-the-Art Industry Resource Josh Stapleton & MCL Staff, Penn State, Materials Research Institute New Deposition Capabilities in the Nanofabrication Laboratory N-203 A&B Susan Trolier-McKinstry, Penn State, Materials Science & Engineering

5:00 p.m. – 7:00 p.m. Graduate Student-Industry Reception and Tabletops NLI-Ballroom

5:30 p.m. Keynote Presentation NLI-Ballroom Technical Glass – A New Era

David Morse, Corning Incorporated

Materials Day 2013

2

Schedule of Events (continued) ___________________________________________________ _________________________ Wednesday, October 16, 2013 __________________________

8:00 a.m. Registration Hetzel Union Building - Outside Alumni Hall 8:30 a.m. – 8:45 a.m. Introduction Hetzel Union Building - Auditorium

Carlo Pantano, Director, Materials Research Institute, Penn State University 8:45 a.m. – 9:30 a.m. Plenary Lectures Auditorium

CEED, a “Crowdsourcing Environment for Evolutionary Design”: From Materials to Manufacturing Joe Salvo, GE Global Research

9:30 a.m. – 10:15 a.m. Invited Presentation Auditorium

Innovation through the Lens of PPG Industries Phil Yu, PPG Industries, Inc.

10:15 a.m. – 11:00 a.m. Invited Presentation Auditorium

Lab-on-a-Chip Technologies Enabled by Acousto-Opto-Fluidics Tony Huang, Penn State, Engineering Science & Mechanics

11:00 a.m. – 11:45 a.m. Invited Presentation Auditorium

Ion Exchange Membranes for New Energy and Clean Water Mike Hickner, Penn State, Materials Science & Engineering

12:00 p.m. – 1:30 p.m. Lunch Hetzel Union Building – Heritage Hall 12:00 p.m. – 2:30 p.m. Interactive Poster Session Alumni Hall

Materials Day 2013

3

Keynote Speaker _______________________________________________________________ TechnicalGlass–ANewEraDr. David Morse, Executive Vice President and Chief Technology Officer, Corning Incorporated Abstract: Corning’s Internet video series, A Day Made of Glass, portrays a vision of an inter-connected future: high bandwidth information delivery with touch-enabled, fixed, and portable displays that would improve essentially every facet of how we live, work, and play. A Day Made of Glass stimulated an entire eco-system of high technology developers to begin collaborating on making this vision a reality. Advances in technical glasses are one of the key enablers required for the vision to become reality. In telecommunications, for example, current research on quantum computing and encryption, single photon switching, and photon entanglement all point to optical telecommunication systems, which will require unique technical glasses. In display technology, various fixed and portable displays will require thin, lightweight, strong, and flexible glasses. These and other developments in technical glasses will be discussed. Biography: Dr. David Morse has served as Corning’s executive vice president and chief technology officer since May 2012. Morse is responsible for managing Corning’s innovation portfolio and creating new growth drivers for the company. Prior to his current position, he served as senior vice president and director, Corporate Research. Morse graduated from Bowdoin College magna cum laude in 1973 and was granted a doctorate from the Massachusetts Institute of Technology in 1976. He is a member of the M.I.T. chapter of Sigma Xi and the National Academy of Engineering. Morse chairs the McDonnell International Scholars External Advisory Committee at Washington University in St. Louis, and is a member of the Board of Industry Advisors of International Materials Institute for New Functionality in Glass (MI-NFG), and the NSF National Board on Chemical Sciences and Technology.

Materials Day 2013

4

Invited Speaker _______________________________________________________________ CEED,a“CrowdsourcingEnvironmentforEvolutionaryDesign”:FromMaterialstoManufacturingDr. Joe Salvo, Manager, Complex Systems Engineering Laboratory, GE Global Research Abstract: The integration of recent technology developments such as cloud computing and crowd sourcing has the potential to change the manufacturing paradigm from ideation through production. By creating global networks of minds, models, and machines at unprecedented scale, the promise of an era of renewed creativity, innovation, and productivity becomes a certainty. The future industrial internet designed for secure and dependable connectivity will be discussed in the context of several transformational application domains. Biography: Dr. Salvo joined the GE Global Research Center in 1988. For the past 15 years Dr. Salvo and his laboratory have developed a series of large-scale internet-based collaboration systems to manage and oversee business operations and deliver value-added services. Some of their commercial business releases include complex decision platforms (e.g. GE Veriwise™ GE Railwise™, Global Vendor Managed Inventory, Ener.GE™, and E-Materials Management) that deliver near real-time customer value through system transparency and knowledge-based computational algorithms. Pervasive networked sensor systems combined with near-real time collaboration can deliver time-critical, high fidelity data to enable information analysis across traditional business process boundaries. Total supply chain, energy management, and financial services can be integrated to create a virtual enterprise environment that encourages discovery and process improvement on a global basis. Distributed knowledge networks extend the reach of these systems with anywhere/anytime access to mission critical information. Dr. Salvo is an active evangelist for the Industrial Internet and believes crowdsourcing and “Smart Manufacturing” platforms have the potential to further democratize the flow of information and ideas. Commercial business implementations of this work are currently active in North and South America as well as in Europe and Asia. His group’s recent work has been described in the New York Times and Wall Street Journal. He is a member of the board at the M.I.T. Forum for Supply Chain Innovation and the IEEE Computer Society.

Materials Day 2013

5

Invited Speakers _______________________________________________________________ InnovationthroughtheLensofPPGIndustriesDr. Phil Yu, Director, Corporate Science & Technology, PPG Industries, Inc. Abstract: PPG Industries, Inc. is a global supplier of paints, coatings, optical products, specialty materials, glass, and fiber glass. It is our vision to continue to be the world’s leading coatings and specialty products company, serving customers in the industrial, construction, consumer products, and transportation markets/aftermarkets. PPG continually seeks technologies that add value and performance to our product offerings. We focus on driving new product developments that align with our business units’ missions in the macro trend sectors of substrate protection, energy, environment, security, and consumer comfort and leisure. To achieve commercialization of new products, PPG looks both internally and externally for technology solutions. Partnerships with companies large and small, collaborations with universities, licensing intellectual property, working with suppliers, and securing government funding to augment research are examples of how we complement and grow our internal science and technology organization. Examples of technologies and partnerships will be reviewed in this presentation. Biography: Phillip received a PhD in Solid State Chemistry from Tufts University and a BS in Chemistry from the University of California at Berkeley. He joined PPG Industries, Inc. in 1991, where he started his career in the Chemicals group. Phil was initially assigned to Optical Products working on electrochromic thin film technologies for eyewear before taking responsibility for the Optical Materials & Coatings group to develop new plastic lens materials and coatings for ophthalmic applications. He was also involved in managing the development of OLED materials for display and lighting applications. During his tenure in Optical, Trivex® lens material, select HiGard® Coatings, and OLED materials were commercialized. For the past six years, Phil has led the Coatings Discovery group, Funded Initiatives team, and today the Corporate Science & Technology function. In his current role, his responsibilities include identifying, validating, and supporting existing and emerging technologies that can be leveraged across all of PPG’s businesses.

Materials Day 2013

6

Invited Speaker _______________________________________________________________ Lab‐on‐a‐ChipTechnologiesEnabledbyAcousto‐Opto‐FluidicsProfessor Tony Huang, Engineering Science and Mechanics, The Pennsylvania State University Abstract: The past decade has witnessed an explosion in lab-on-a-chip research. This rapid development has occurred mainly because of the continuous fusion of new physics into microfluidic domains. In recent years, researchers have made significant progress in joining acoustic and optical technologies with microfluidics. Optofluidics, the merger between optics and microfluidics, enables the creation of reconfigurable optical components that are otherwise difficult to implement with solid-state technology. Acoustofluidics, on the other hand, offers noninvasive solutions for many on-chip biomedical applications. In this talk, I will present several lab-on-a-chip innovations enabled by acoustofluidics and optofluidics, including acoustic tweezers, tunable optofluidic and plasmofluidic lenses, and miniature fluorescence-activated cell sorters (FACS). These technological innovations have many advantages and are packaged in simple, elegant designs. For example, our acoustic tweezers operate at ~107 times lower power intensity than current optical tweezers. The low power intensity renders our technology noninvasive toward biological samples, as confirmed by experimental results. Moreover, the acoustic tweezers are amenable to miniaturization and versatile—they can be applied to virtually any type of cells or microparticles regardless of size, shape, or electrical/magnetic/optical properties. With the advantages in versatility, miniaturization, power consumption, and technical simplicity, our acoustic tweezers technique is expected to become a powerful tool in many applications, including tissue engineering, microarrays, stem cell biology, and drug screening/discovery. Biography: Tony Jun Huang is a professor in the Department of Engineering Science and Mechanics at The Pennsylvania State University. He received his Ph.D. degree in Mechanical and Aerospace Engineering from the University of California, Los Angeles (UCLA) in 2005, and his B.S. and M.S. degrees in Energy and Power Engineering from Xi’an Jiaotong University, Xi’an, China, in 1996 and 1999, respectively. His research interests are acoustofluidics, optofluidics, and micro/nano systems for biomedical applications. He has authored/co-authored over 110 peer-reviewed journal publications and over 140 peer-reviewed conference papers in these fields. He serves as Vice Chair of the American Society of Mechanical Engineers (ASME) Nanoengineering Council and chair of the ASME Society-Wide Micro/Nano Technology Forum. His research findings have been recognized with awards and honors such as the 2006 Rustum and Della Roy Innovation in Materials Research Award, a 2010 National Institutes of Health (NIH) Director’s New Innovator Award, a 2011 Penn State Engineering Alumni Society Outstanding Research Award, a 2011 JALA Top Ten Breakthroughs of the Year Award, a 2012 Outstanding Young Manufacturing Engineer Award from Society for Manufacturing Engineering, a 2013 Faculty Scholar Medal from The Pennsylvania State University, and a 2013 American Asthma Foundation (AAF) Scholar Award. More information about him and his research group can be found at www.esm.psu.edu/huang.

Materials Day 2013

7

Invited Speaker _______________________________________________________________ IonExchangeMembranesforNewEnergyandCleanWaterProfessor Michael Hickner, Materials Science and Engineering, The Pennsylvania State University Abstract: Renewable energy and sustainable clean water are two of the largest societal challenges of our time. New polymers are being sought as solid-state electrolytes and ion exchange membranes to advance research in alternative energy and water purification technologies. In many cases, the motion and confinement of ions and water in fuel cell, battery, and reverse osmosis membranes have many common mechanistic characteristics across different sets of polymeric materials that absorb water to function. We have designed new classes of polymers with self-assembled ionic nanoscale channels and measured their ion and water diffusion, ion conductivity, and ionic domain morphology using a variety of spectroscopic and scattering techniques. The performance characteristics of these polymers in fuel cells, aqueous redox flow batteries, and reverse electrodialysis devices were connected to their fundamental molecular transport properties and nanophase morphology. Thus, we can influence device performance directly by rational design of polymer chemical structure and self-assembly of the functionalized polymers. This talk will describe our work in manipulating the chemical structure, self-assembly, and interaction of polymers with water and ions to target specific properties that create new opportunities for low-cost energy storage devices and water treatment membranes. Biography: Michael A. Hickner received a B.S. in Chemical Engineering from Michigan Tech in 1999 and a Ph.D. in Chemical Engineering from Virginia Tech in 2003. Before joining the Department of Materials Science and Engineering at Penn State in 2007, he was a staff research scientist at Sandia National Laboratories. His research group at Penn State is focused on the synthesis and properties of ion-containing polymers, measurement of water-polymer interactions using spectroscopic techniques, and the study of self- and directed assembly of polymeric nanostructures for fast transport. He has ongoing projects in new polymer synthesis, fuel cells, batteries, water treatment membranes, and organic electronic materials. Hickner’s work has been recognized by Young Investigator Awards from ONR and ARO in 2008, a 3M Non-tenured Faculty Grant in 2009, the Walker Faculty Fellowship from the College of Earth and Mineral Sciences in 2010, the Rustum and Della Roy Innovation in Materials Research Award in 2013, and a Presidential Early Career Award for Scientists and Engineers from President Obama in 2009. He has five US and international patents and over 100 peer-reviewed publications since 2001 that have been cited more than 4600 times with an H-index of 29.

Materials Day 2013

8

Poster Listing by Research Category ______________________________________________ Biomaterials and Medical Devices (25 posters) 1 Soft Material Chemistry Approaches for Fabrication of Nano Elements for Microscale and

Mesoscale Applications J. Adair, X. Tang, B. Babcox, E. Landis, W. Loc, D. Franey, A. Van Orden, E. Taylor, M. Li, Z. Miao, D. Kumpf, A. Butler, B. Adair

2 Surface Functionalization of Gate Dielectrics for Biosensing Applications K. Liddell, C. Keating

3 Polyphosphazenes Designed for Biomedical Applications J. Nichol, H. Allcock

4 Utilizing Biophysical Techniques to Investigate RNA:Protein Interactions in the RNA Interference Pathway K. Quarles, D. Sahu, R. Acevedo, S. Showalter

5 Fluorescence-imaging Enabled Biodegradable Photoluminescent Polylactones Z. Xie, J. Yang

6 Highly Aligned Conducting Polymer Nanotubes Improve Axonal Regeneration G.Yang, A. Greever, M. Abidian

7 Advanced Nanobiomaterials for Multifunctional Neural Interfaces M. Abidian

8 Understanding Intracellular Organization Using Model Systems Based on Polymer/Salt Solutions and Gold Nanoparticles W. Aumiller Jr., B. Davis, C. Keating

9 Programmable Nucleic Acid Polymerization for Nanoparticle-Mediated Imaging of the ECM N. Chen, Y. Wang

10 Characterization of Intracellular Organization within Biphasic Polymer Solutions B. Davis, W. Aumiller, Jr., C. Keating

11 Specific Biomimetic Hydroxyapatite Nanotopographies Enhance Bone Isograft Osteointegration A. Loiselle, L.Wei, G.Lewis, E. Paul, A. Lakhtakia, H. Donahue

12 Characterization of the Size, Shape, and Drug Encapsulation Efficiency of PLGA Microcapsules Produced Via Electrojetting for Anticancer Agent Delivery P. Fattahi, A. Borhan, M. Abidian

13 A Label-free Droplet-based Optofluidic Detection Device F. Guo, M. Lapsley, T. Huang

14 Hybrid Conducting Polymer Hydrogel Nanofibers for Glucose Detection G. Kim, M. Abidian

15 Transcriptional Variations of a Bioelastomeric Adhesive T. Ozdemir, A. Francesh, Y. Nur, M. Demirel

16 Adhesion Mechanism of a Protein Melt A. Pena-F, B. Akgun, W. Zhu, H. Gao, M. Demirel

17 Metallomembranes: Exploring Transtion Metal/Lipid Complexes M. Poyton, X. Cong, A. Sendecki, P. Cremer

18 Synthesis and Characterization of Biomimetic Citrate-Based Osteoinductive Composites R. Tran, C. Zhang, B. Banik, J. Brown, J Yang

19 Active Bone-Crack Detection, Targeting, and Repair using Ion Gradients V. Yadav, J. Freedman, M. Grinstaff, A. Sen

20 Blood Plasma Biomarker Separation Using a MEMS Device Integrated with a Vertically Aligned Carbon Nanotube Membrane Y-T. Yeh, S. Trolier-McKinstry

21 Design and Synthesis of Thermally Stable Reagents and Paper-based Microfluidic Devices for Point-of-Care Diagnostics K. Yeung, S. Phillips

Materials Day 2013

9

22 Novel Nanoparticle Contrast Agents for Multimodal Imaging Based on Near Infrared, Magnetic

Resonance Imaging, and Photoacoustic Imaging X. Tang, D. Natale, M. Kester, S. Knecht, T. Neuberger, R. Tutwiler, J. Adair

23 Micromachined Magnetic Sensors G. Hatipoglu, F. Li, N. Goel, S. Datta, S. Tadigadapa

24 Majd Lab: Cellular Biophysics and Nanotechnology Laboratory S. Park, C-F. Kuo, Y.Kang, S. Majd

25 Preparation of Vesicles with Controlled Size and Composition as Cell Membrane Mimics Y. Kang, H. Wostein, and S. Majd

Computer Simulation and Modeling (7 posters) 26 Phase-field Simulation of Defect Transport and Resistance Degradation Behavior in Single

Crystal BaTiO3 Y. Cao, J. Shen, C. Randall, L. Chen

27 A FFT-based Elasto-viscoplastic Phase-field Model for Recrystallization L. Chen, J. Chen, Y. Ji, T. Heo, S. Bhattacharyya, R. Lebensohn, S. Mathaudhu, Z. Liu

28 Phase-Field Simulation of Anisotropic Li Intercalation in LixFePO4 Nano-Particles L. Hong, L.-Q. Chen

29 Transport and Mixing of Materials into-and-out-of Dead End Pores A. Kar, T. Chiang, I. Ortiz, A. Sen, D. Velego

30 Characterization and Constitutive Material Model Implementation for High-Strain-Rate Deformation Modeling with Finite Elements J. Schreiber, I. Smid, T. Eden

31 Calculation of Impurity Diffusion Coefficients in Mg Using First-principles Methods B-C. Zhou, S. Shang, Y. Wang, Z-K. Liu

32  Fluorination of Graphene, Gas Sensing on Carbon-based Materials, Proximity Effects of Graphene/Topological Insulators, and Spectral Analysis of Water/Metal-oxide Surface: Physics of Adsorption and Interfaces P. Aditya, M. DelloStritto, S. Liang, G. Yang, J. Sofo

Electronic/Photonic Materials and Devices (26 posters) 33 Metals and Alloys for Electronics and Related Applications

S. Mohney 34 Center for Dielectrics and Piezoelectrics

C. Randall 35 Low Temperature Deposition and Fabrication of ZnO TFTs for Flexible Electronics

H. Li, J. Ramirez, M. Lee, H. Fok, T. Jackson 36 On-Axis Growth of SiC Epitaxial Layers by Halide CVD for High Voltage Power Devices

M. Fanton, D. Snyder, B. Weiland, R. Cavalero, K. Trumbull, G. Pastir 37 Bulk Ionic Conductivity of Glass and Glass-Ceramic Lithium Thiophosphate Solid Electrolytes

for Solid-state Batteries & Electrochemical Capacitors S. Berbano, M. Mirsaneh, M. Lanagan, C. Randall

38 Synthesis of Tungsten Diselenide Thin Films P. Browning, S. Eichfeld, K. Zhang, Y-C. Lin, C. Lee, G. Bhimanapati, L. Hossaine, J. Robinson

39 Conjugated Block Copolymer Photovoltaics with near 3% Efficiency through Microphase Separation C. Guo, Y-H. Lin, M. Witman, K. Smith, C. Wang, A. Hexemer, J. Strzalka, E. Gomez, R. Verduzco

40 Integrated Dielectric Materials for Electronics M. Lanagan

41 Advanced Electroactive Materials and Devices Q. Zhang

Materials Day 2013

10

42 Structure-property Relationship for SnS Thin Films and Single Crystal Material: Study of the

Optoelectronic Properties of SnS for Photovoltaic Applications M. Horn , J. Brownson , A. Cröll, T. Songfrei, C. Giebink, S. Choi, Research team: Horn-Brownson Research Group

43 Nature Inspired Optimization of Broadband Absorbers, Mirrors, and Metamaterials for the Infrared J. Bossard, Z. Jiang, L. Lin, S. Yun, X. Wang, D. Werner, T. Mayer, Z. Liu

44 Templated Hydrogenated Amorphous Silicon Conformal Coatings T. Day, R. He, N. Healy, A. Peacock, P. Sazio, J. Badding

45 Light Trapping Schemes for Enhanced Light Absorption S. Hall, T. Mallouk

46 Dielectric and Piezoelectric Properties upon Lateral Scaling of PMN-PT Films for Logic R. Keech, S. Shetty, S. Trolier-McKinstry, D. Newns, M. Copel, G. Martyna, T. Shaw, T. Theis

47 Electric-Field-Assisted Assembly of 2D Sheets to Form Field-Effect Transistors S. Levin, J. Li, D. Sun, D. Vaughn II, M. Bresnehan, J. Robinson, R. Schaak, T. Mayer

48 Light Manipulation Using Plasmonic Nanoparticles A. Panaretos, F. Namin, and D. Werner

49 ZnO Thin Film Electronics for Circuits Anywhere I. Ramirez, K. Sun, Y-C. Li, Y. Goh, T. Jackson

50 Computationally-aided Design of Li-ion and Fluoride-ion Batteries for Facile Ion Transport H-S. Shiau, M. Janik, R. Colby

51 Carbon Nanofiller Modified Electroactive Polymers N. Sigamani, Z. Ounaies

52 Recent Developments on High Performance Piezoelectric Crystals S. Zhang, Z. Shen, Y. Tang, T. Shrout

53 Ultralow Resistance Ohmic Contacts to III-V and III-N Semiconductors M. Abraham, W. Choi, S-Y. Yu, S. Mohney

54 Growth of High Performance Oxide Thin Films Using Low Energy Growth Techniques C. Eaton, R. Haislmaier, H. Zhang, L. Zhang, Y. Zheng and R. Engel-Herbert

55 Novel Optical Microsensing Devices P. Edwards, C. Yang, N. Mehta, C. Janisch, C. Zhang, Z. Liu

56 Optical Characterization of Unique Engineered Materials C. Janisch, D. Ma, N. Mehta, Z. Liu

57 Epitaxial Growth and Characterization of Gate-tunable Topological Insulator/ Insulating Ferromagnet Heterostructures A. Richardella, A. Kandala, J. Lee, T. Flanagan, R. Fraleigh, N. Samarth, M. Liu, N. Ong, R. Cava, J. Heron, D. Schlom

58 MEMS Piezoelectric Energy Harvesting C. Yeager, H. Yeo, S. Trolier-McKinstry

Materials Characterization (19 posters) 59 Carbon Materials Synthesized from the Cold Compression of Aromatic Hydrocarbons and

SWNTs T. Fitzgibbons, M. Guthrie, E. Xu, Y. Lin, W. Mao, V. Crespi, G. Cody, R. Hoffmann, J. Badding

60  XPS and AES: Important Characterization Tools for the Physical, Engineering, and Life Sciences V. Bojan

61 Materials Characterization: Using Solid-State NMR to Understand the Formation and Role of Surface Alteration Layers on Nuclear Waste Glass K. Murphy, N. Washton, J. Ryan, C. Pantano, K. Mueller

62 Enhancing Signal-to-noise Ratio in Zero-mode Waveguide-based Single-molecule Fluorescence Studies by Dark Field Illumination D. Chen, Y. Zhao, H. Yue, C. Zhao, T. Huang, S. Benkovic

Materials Day 2013

11

63 Mechanism of Enhanced Carbon Cathode Performance by Nitrogen Doping in Lithium-sulfur

Battery – an X-ray Absorption Spectroscopic Study P. Zhu, J. Song, D. Lv, D. Wang, Y. Chen

64 Focused Ion Beam/Scanning Electron Microscopy (FIB/SEM): Why Every SEM User Should Know about This T. Clark, Materials Characterization Lab

65 Scanning Electron Microscopy (SEM): Imaging Tough Samples with High Contrast and High Resolution T. Clark, Materials Characterization Lab

66 A Detailed TEM Study of Carbon Nano-onions Structure C. Gaddam, R. Vander Wal

67 Transmission Electron Microscopy: Structural and Chemical Characterization from the Micron Down to the Atomic Scale J. Gray, T. Clark, J. Maier, K. Wang

68 Sub-Angstrom Structural Distortions in an Atomically Thin Hexagonal Boron Nitride Membrane N. Alem

69 The High Field MRI Facility at Penn State T. Neuberger

70 Scanning Probe Microscopy within the Materials Characterization Lab T. Tighe

71 Connecting with the Materials Characterization Lab MCL Staff

72 Characterization and Structure Analysis of Faujasites from a Jordanian Volcanic Ash D. Vaughan, H. Yennawar, Anthony J. Perrotta+

73 MCL Electrical Characterization Lab M. Lanagan, J. Long, S. Perini, R. Wilke

74 Materials Characterization – X-ray Scattering Techniques N. Wonderling

75 Multiscale Stress-strain Characterization of Outer Onion Epidermal Peel Tissue K. Kim, A. Haque, S. Zamil, H. Yi, V. Puri

76 Characterization of a Corrosion Resistant Coating for Steel and Glass J. Mattzela, C. Pantano

77 Using Traditional Surface Characterization Techniques in Novel Ways: from Developing Lubrication in MEMS to Elucidating Cellulose Crystal Structure for Biofuels A. Barthel, C. Lee, A. Al-Azizi, K. Kafle, N. Surdyka, S. Kim

Materials Processing and Manufacturing (23 posters) 78 Biomass Conversion: Converting Sugars into Fuels and Chemical Building Blocks for Plastics

W. Yang, F. Pong, A. Sen 79 AnInsolubleStarch‐basedFoamProducedthroughMicrowaveExpansion

Y.Deng,J.Catchmark80 Conventional- and Microwave-hydrothermal Synthesis of BiVO4

M. Sarkarat, S Komarneni 81 Polymer Derived Carbons for Energy Related Applications

R. Rajagopalan 82 Sequestration, Retention, and Release of Solutes Using Aptamer-functionalized Polymeric

Materials M. Battig, S. Li, Y. Wang

83 Stimuli-responsive Plastics that Respond to Trace Signals via Depolymerization M. Olah, A. DiLauro, S. Phillips

Materials Day 2013

12

84 MOCVD Growth of Group III-Nitrides

J. Gagnon, Z. Al Balushi, S. Eichfeld, H. Shen, Y. Yuwen, T. Mayer, J. Redwing

85 Process-structure-property Relationships of Thick Gd2O3 Films for Neutron Detection D. Grave, D. Wolfe

86 Oxides Thin Films for Infrared Imaging Prepared by Biased Target Ion Beam Deposition Y. Jin, T. Jackson, M. Horn

87 Horn Thin Film Group M. Horn, Y. Jin, H. Basantani, H. Lee, R. Banai, F. Aronovich, N. Tanen, M. Nunez, R. Gresh, A. Narccarelli

88 Investigation of the Use of a Laser-sustained Plasma (LSP) in Titanium Nitriding A. Kamat, J. Todd

89 The Center for Innovative Material Processing through Direct Digital Deposition F. Lia, R. Martukanitz

90 Multidisciplinary Research for Additive Manufacturing at CIMP-3D F. Lia, R. Martukanitz

91 Surface Reactivity of Hydroxyl Groups on Aluminum Oxide Powders Probed with Chlorotrimethylsilane B. Ludwig, J. Stapleton, C. Pantano

92 Battery and Energy Storage Technology (BEST) Center Co-Directors: C. Rahn, C-Y. Wang

93 Advanced Thermal Barrier Coating Concepts Utilizing Unique Design Architectures M. Schmitt, D. Wolfe

94 Conditioning of Composite Lubricant Powder for Cold Spray M. Neshastehriz, I. Smid, A. Segall, T. Eden

95 Drag Reduction of Slippery Liquid-infused Porous Surfaces N. Sun, T. Wong

96 Spectroscopic Evidences of Atomic Hydrogen Adsorption via Spillover Effect on Metal-Organic Framework Catalysts C-Y. Wang, Q. Gong, J. Li, A. Lueking

97 Bioinspired Omniphobic Slippery Coatings on Industrial-relevant Metals J. Wang, K. Kato, N. Sun, A. Blois, T-S. Wong

98 Ion-Beam Assisted Thin Film Growth by Biased Target Deposition H. Basantani, F. Aronovich, M. Horn, W. Drawl, S. Trolier-McKinstry

99 Templated Growth of Amorphous Carbon Films D. Keefer, J. Badding

100 Kinetics and Universality of Gate Adsorption in Flexible Metal-organic Frameworks for Gas Trapping S. Sircar, A. Lueking

Nanomaterials and Nanofabrication (20 posters) 101 Chemotactic Separation of Enzymes

K. Dey, S. Das, M. Poyton, S. Sengupta, P. Cremer, A. Sen 102 Topological Phases in InAs/GaSb Type II Quantum Wells

C. Liu 103 Two-dimensional Layered Materials

J. Zhu 104 Low Dimensional Systems and Their Composites for New Technologies

K. Adu, D. Ma, P. Shetty, D. Hess, D. Capliger, R.Bell 105 Ultrathin Self-assembled Single-walled Carbon Nanotube Electrodes for Design of Flexible Electrochemical Capacitors

D. Ma, C.Randall, R. Rajagopalan, K. Adu

Materials Day 2013

13

106 Shape-controlled Synthesis of Semiconducting SnS Nanocrystals and Evidence for a Structural

Distortion at the Nanoscale A. Biacchi, D. Vaughn II, R. Schaak

107 Engineering Spontaneous Phenomena A. Drew, Bishop Group

108 Two-dimensional Materials & Devices S. Eichfeld, G. Bhimanapati, P. Browning, C. Lee, Y. Lin, M. Hollander, T. Miyagi, J. Distefano, L. Hossain, K. Zhang, D. Kozuch, A. Alonso, and J. Robinson

109 Dispersion Strategies and Role of Interfacial Phenomena in Polymer Nanocomposites P. Khodaparast, Z. Ounaies

110 Vertical Nanowire Assembly Directed by Lithographic Microwells D. Kirby, B. Smith, A. Wustrow, C. Keating

111 Theory of Proximity Induced Triplet Superconductivity in Spin-orbit-coupled Systems X. Liu, J. Jain, and C-X. Liu

112 Metal Phosphide and Chalcogenide Electrocatalysts for Clean Energy Technologies E. Popczun, R. Schaak

113 Applications of Conformal Thin Films on Non-traditional/Non-planar substrates D. Pulsifer, A. Lakhtakia

114 Processing Pathways for Silicon Micro/Nanowire Array Solar Cells Redwing Group

115 Adaptive and Responsive Nanoparticle Amphiphiles K. Bishop, H-Y. Lee, S. Shin

116 Nanofabrication Laboratory: An MRI Shared User Facility 117 Center for 2-Dimensional and Layered Materials at Penn State

M. Terrones, J. Robinson 118 Hybrid Ferromagnetic/Semiconducting Nanowires for Nano-spintronics

J. Kally, S. Yu, D. Kim, S. Tadigadapa, S. Mohney, M. Chan, N. Samarth 119 Mechanochemistry of Carbon Cages to Explore C-H Interactions

P. Ray, E. Xu, T. Fitzgibbons, A. Lueking, J. Badding,V. Crespi 120 Polarization-independent Broadband Absorber Based on Engineered Nanostructures

Y. Yuwen, L. Lin, F. Namin, J. Bossard, L. Liu, D. Werner, T. Mayer

Materials Day 2013

14

Poster Listed by Abstracts _______________________________________________________ Poster 1 ______________________________________________________________________ Soft Material Chemistry Approaches for Fabrication of Nano Elements for Microscale and Mesoscale Applications J. Adair, X. Tang, B. Babcox, E. Landis, W. Loc, D. Franey, A. Van Orden, E. Taylor, M. Li, Z. Miao, D. Kumpf, A.Butler, B. Adair Abstract: Soft chemistry approaches are demonstrated for a variety of materials and applications areas including nanomedicine and structural material applications ranging from the treatment of cancer and aerospace structures. The calcium phosphosilicate nanoparticles invented at Penn State are emerging as a useful tool in the early detection and treatment of human cancer. The encapsulation of bioimaging agents and chemotherapeutics in targeted, composite, colloidal nanoparticles for specific cancers including breast, pancreatic, osteosarcoma (lung), and chronic myeloid leukemia have been demonstrated in vitro and in vivo in animal models.

Implementation of nanoscience in structural components for nanomedical applications such as mesoscale surgical instruments and high strength and strain, low weight elements will also be presented. Surgical instruments especially designed at mesoscale, in which all of the dimensions are less than one millimeter, have been designed and fabricated. The iterative approach encompassing design with both protoyping and large scale production are summarized with emphasis on the development of high strength materials and precise dimensional tolerance are demonstrated based on the patented lost-mold forming manufacturing process developed at Penn State. The critical engineering issues that were overcome through the iterative approach will be presented. The mesoscale Y-TZP components have average strength over 2,300 MPa based on the Weibull distribution and edge resolution less than 1 micron. Poster 2 ______________________________________________________________________ Surface Functionalization of Gate Dielectrics for Biosensing Applications K. Liddell, C. Keating Abstract: Field-effect transistors (FETs) have the potential to combine powerful microchip computing with biological samples to produce a highly sensitive and multiplexed sensing device. Traditionally, silica has been used as the gate dielectric to insulate the electronic components in solution-based measurements, but more recently we have examined alternative high-k materials. As such, understanding DNA hybridization on alumina, tantalum oxide, or hafnium oxide is of interest as this has been extensively studied on silica but is less understood with other materials.

Organosilanes are the most common route to chemically modify silica for coupling bioactive molecules such as biotin, DNA, or PNA. However, decreased stability on other dielectric materials at physiological conditions has been observed. Alkyl phosphonic acids can form self-assembled monolayers (SAMs) on a variety of non-silica metal oxides, but long reaction times make them less compatible for industrial scale-up. This poster will describe fabrication, characterization, and optimization of phosphonic acid monolayers with end terminal functionality on gate dielectrics used to couple biomolecules onto FETs.

The incorporation of biomolecules in semiconductor fabrication schemes presents challenges to maintain hybridization/capture efficiency of immobilized probe molecules. Many photolithographic processes use high temperatures and/or harsh solvents that could degrade probe molecules. We are interested in studying what effect, if any, different treatments of common photolithographic steps have on biomolecules attached to the surface. Poster 3 ______________________________________________________________________ Polyphosphazenes Designed for Biomedical Applications J. Nichol, H. Allcock Abstract: Both natural and synthetic polymers have been examined in an attempt to generate scaffolds which mimic the properties of damaged tissue and ultimately allow the body to heal from injury. Polyphosphazenes are an ideal platform for this application due to their high degree of chemical tunability allowing for the development of polymers with specific chemical and physical properties. Synthesis of these polymers begins with poly(dicholorophosphazene) which has a flexible backbone of alternating nitrogen and phosphorus atoms, with each phosphorus bearing two additional chlorine atoms. This polymer then undergoes nucleophilic substitution by various alkoxides and amines to replace the chlorine atoms and impart the desired final properties. Several hundred different nucleophiles have been shown to participate in this reaction, providing an even larger number of final polymers with a wide array of properties. Previously designed polymers for potential bone tissue engineering applications utilized amino acid ethyl ester substituted polyphosphazenes that were shown to degrade into a non-toxic buffered medium. Separate research has also shown that polyphosphazenes containing long alkoxy side chains generate biostable elastomeric polymers. My research has focused on bridging these two systems to generate polyphosphazenes that are both elastomeric and biodegradable. By utilizing structurally similar side groups to those used previously to make elastomeric polyphosphazenes, along with incorporating a hydrolytically sensitive component, we anticipated that we would be able to obtain polymers that fulfill both requirements of ligament and tendon tissue engineering scaffolds. Current research revolves around the development of an injectable tissue adhesive hydrogel.

Materials Day 2013

15

Poster 4 ______________________________________________________________________ Utilizing Biophysical Techniques to Investigate RNA:Protein Interactions in the RNA Interference Pathway K. Quarles, D. Sahu, R. Acevedo, S. Showalter Abstract: Since their discovery in 1996, microRNAs (miRNAs) have been shown to play a critical role in several developmental and differentiation processes in the human body; in addition, their misfunction has been linked to the advancement of a plethora of disease states including cancer, neurodegenerative disease, heart disease, and autoimmune disease. Mature miRNAs are ~22-nucleotide-long single-stranded (ss) non-coding RNAs that have been found in worms, plants, flies, and mammals. Despite their importance, very little is known about the maturation process of miRNAs from their precursor primary miRNAs (pri-miRNAs) at the atomic level. In addition, the role that pri-miRNA secondary structure plays in recognition by the Microprocessor complex for maturation is only qualitatively defined. Most importantly, the lack of experimentally-derived pri-miRNA structures impedes the potential understanding of the structure-function relationship between pri-miRNA and the Microprocessor’s protein components, DGCR8 (key binder of pri-miRNA) and Drosha (catalytic cleavage enzyme). However, the means by which Drosha locates and recognizes the cleavage site is believed to play a critical role in Microprocessor efficiency and must be known to fully understand miRNA biogenesis. Therefore, my goal has been to fully characterize the interactions of the Microprocessor proteins with pri-miRNA by first determining what structural characteristics of the RNA are important for Microprocessor recognition. Poster 5 ______________________________________________________________________ Fluorescence-imaging Enabled Biodegradable Photoluminescent Polylactones Z. Xie, J. Yang Abstract: The use of degradable polymeric materials such as polylactide (PLA), polyglycolide (PGA), and their copolymers has generated huge scientific and economic impact on a broad range of biomedical applications including drug delivery, tissue engineering, and cancer imaging in the past few decades. In tissue engineering, designing biomaterials with suitable degradation rate remains empirical to some degree due to the lack of in vivo quantitative validation for the benchmarks obtained from in vitro studies. It is imperative to find an in-situ real-time method to facilitate tracking or monitoring scaffold degradation processes continuously without sacrificing animals. This issue has rarely been addressed previously. In drug delivery, tracking drug delivery process and monitoring treatment efficacy have been central in theranostic nanomedicine. However, encapsulating/conjugating imaging agents in/on nanoparticles may result in increased particle sizes, additional complexity, and higher risk of adverse biological reactions. The above emerging challenges might be resolved using biodegradable polymers, which themselves serve as both implants and imaging probes. However, the existing polylactones do not meet the ever-increasing functionalities, especially imaging function, required for the next generation of biomaterials. Our recent progress has resulted in the biodegradable photoluminescent polymers (BPLPs) without using any photobleaching and cytotoxic organic dyes or quantum dots. Herein, we report the first series of biodegradable photoluminescent polylactones (BPLPL), exemplified with photoluminescent polylactide (BPLP-PLA). Poster 6 ______________________________________________________________________ Highly Aligned Conducting Polymer Nanotubes Improve Axonal Regeneration G.Yang, A. Greever, M. Abidian Abstract: Nerve injury in both central and peripheral nervous system is a major health problem. Spontaneous axonal regeneration is limited to small lesions within the injured peripheral nervous system and is actively suppressed within the central nervous system. Axons are guided along specific pathways by gradients of attractive and repulsive chemical and physical cues. To understand the effect of guidance cues on axon growth rate, development of in vitro platforms that are capable of producing precisely controlled shape guidance cues is essential. Conducting polymers have been widely used in biomedical applications, in particular, for drug delivery systems and neural interfaces. Previously, we developed a novel method for fabrication of randomly oriented conducting polymer nanotubes for controlled release of an anti-inflammatory drug. We hypothesize that the aligned conducting polymer nanotubes will provide both physical and chemical guidance for axonal regeneration. Poster 7 ______________________________________________________________________ Advanced Nanobiomaterials for Multifunctional Neural Interfaces M. Abidian Abstract: Neural interfaces, including neural electrodes, are increasingly applied for the treatment of neurological disorders such as Parkinson’s disease, hearing loss, and chronic pain. Moreover, these implants hold the promise to return functionality to individuals with neurodegenerative diseases such as paralysis and connectivity with advanced prosthetics. While neural recordings and stimulations have become routine in animal neurophysiology research and have begun to be tested on humans, robust and stable long-term functionality remains a significant challenge. Current neural microelectrodes suffer from high impedance because of their small-feature size. Furthermore, insertion trauma and immune responses’ encapsulation process cause neuronal cell loss and progressively

Materials Day 2013

16

increase the impedance of electrode-tissue interface over the long term, leading to the device failure. To increase the chronic life span of these electrodes and to obtain reliable and high quality neural recordings, novel strategies are required to improve electrical properties, enhance the biocompatibility, and maintain normal neuronal density around the electrode.

Abidian research group works at the interface of biomaterials and electronic devices to develop next-generation neural interfaces. Engineering these systems requires an interdisciplinary approach that incorporates aspects of polymer synthesis, micro/nano-fabrication techniques, and cell-biomaterials interactions. These electronically active devices have a broad range of applications such as controlled drug delivery, neural recording, and stimulation, neurochemical sensing, and axonal regeneration.

Current efforts are focused on the following areas: • Multifunctional organic-inorganic hybrid nanobiomaterials for smart targeted drug delivery to brain tumors • Bioactive conducting polymer and carbon nanotubes for axonal regeneration and biotic-abiotic interface of neural

prostheses • Chronic, selective, and sensitive detection of neurochemicals using conducting polymer micro/nano-tubes

Poster 8 ______________________________________________________________________ Understanding Intracellular Organization Using Model Systems Based on Polymer/Salt Solutions and Gold Nanoparticles W. Aumiller Jr., B. Davis, C. Keating Abstract: The intracellular environment in which biological reactions occur is a complex solution, composed of many different microenvironments with differing local concentrations of ions, small molecules, nucleotides, and proteins. These different environments exist in close proximity to one another, and biological reactions have evolved to occur in this heterogeneous media. Here, we report two experimental model systems of polymer/salt solutions and enzyme nanoparticle bioconjugates that captured aspects of the intracellular environment.

The first model system described was composed of a polyethylene glycol (PEG) /citrate aqueous two phase system (ATPS) in which the sequential reaction of glucose oxidase and horseradish peroxidase occurred. We found that the enzymes and substrates partitioned in the ATPS, which resulted in different local concentrations and therefore different rates of reaction. Using the kinetic data, we developed a mathematical model that described the kinetics of the reaction in the two-phase environment, and we then used the model to predict a case in which the concentration of enzyme was higher. The second model system described used functionalized gold nanoparticles for biomolecule localization. An enzyme of the de novo purine biosynthesis pathway was expressed and purified with a his-tag, followed by chemical labeling of the enzyme with a fluorescent dye. The labeled enzyme was immobilized to the surface of nickel(II)–nitrilotriacetic acid (Ni2+–NTA) functionalized gold nanoparticle scaffolds via the his-tag. The enzyme remained active upon immobilization. The gold nanoparticle scaffolds were structurally characterized using dynamic light scattering and UV-vis absorbance.

This poster also briefly summarizes work I have done as an intern with the Office of Technology Management at Penn State in which I reviewed patented technology and gave technical advice on patent applications. Poster 9 ______________________________________________________________________ Programmable Nucleic Acid Polymerization for Nanoparticle-Mediated Imaging of the ECM N. Chen, Y. Wang Abstract: The ability to image a tissue with high sensitivity and high contrast holds great potential to detect diseases at early stages, guide the design of therapeutic protocols, and monitor the outcome of treatment. Therefore, great efforts have been made to develop novel nanoparticle technologies with the hope to produce strong signal intensity in target tissues rather than non-target ones. However, normal tissues in the human body, e.g., liver and spleen, can nonspecifically entrap a significant amount of nanoparticles carrying imaging agents, therefore it’s still challenging to achieve a high ratio of target to non-target signal. To approach this problem, we herein proposed a new concept, which integrates nanoparticle-mediated molecular recognition and programmed DNA polymerization to achieve signal amplification in the target tissue. In this concept, nanoparticles do not function as the imaging agents directly, but they play the role of targeting and accumulating functional oligonucleotides in the target tissue. Antibodies are used to functionalize nanoparticles to mediate specific and strong interactions between nanoparticles and target tissue components. In addition to antibody, a DNA initiator (DI) is presented on the surface of nanoparticles, which can initiate structural changes and sequential hybridizing of two metastable DNA monomers (DM1 and DM2) into a DNA polymer. Thus, when DM1 and DM2 carry imaging agents, their cascade polymerization and accumulation on DI-functionalized nanoparticles will lead to the signal amplification. Thus, nanoparticles play a multiple role of targeting tissues, presenting DI, and accumulating DNA monomers to induce signal amplification. We confirmed a significant increase of the molecular weight after DNA polymerization by gel electrophoresis and SPR. In addition, a strong increase of fluorescence in flow cytometry and fluorescence imaging can also be observed. More importantly, a bright green fluorescence in the confocal microscopy images demonstrated that the programmed DNA polymerization for nanoparticle-mediated ECM imaging was successful. Therefore, nanoparticle-mediated molecular targeting and DNA programming hold great potential to advance the imaging for clinical applications.

Materials Day 2013

17

Poster 10 _____________________________________________________________________ Characterization of Intracellular Organization within Biphasic Polymer Solutions B. Davis, W. Aumiller, Jr., C. Keating Abstract: Aqueous biphasic polymer solutions, often used in biotechnology separations, were employed as model systems to study the effects of biomolecule localization. The cytoplasm is a dynamic environment that plays an important role in cellular metabolism as sequential enzymes of several metabolic pathways are known to exist within close proximity. Phase separation induced by macromolecular crowding within the cytoplasm has been described as the basis for microcompartmentalization and subsequent colocalization of biomolecules may provide a means of regulation within a metabolic pathway. Aqueous solutions of structurally distinct polymers, a polymer and a salt, or oppositely charged polyelectrolytes phase separate over specific weight percents. Enzymes and substrates preferentially partition to one of the phases, thus increasing local concentration while total volume remains constant. The common sequential enzyme pair of glucose oxidase and horseradish peroxidase was introduced into a polyethylene glycol (PEG);citrate biphasic system while enzymes of the purine biosynthesis pathway were used in a PEG:dextran system. Product formation was monitored by fluorimetry and HPLC, respectively, and a mathematical model was used to elucidate the effects of compartmentation. This colocalization of enzymatic activity through phase separation serves as a cytoplasm mimic but may also find relevance in biotechnology applications that require efficient multi-step enzymatic catalysis to produce a desired product. Poster 11 _____________________________________________________________________ Specific Biomimetic Hydroxyapatite Nanotopographies Enhance Bone Isograft Osteointegration A. Loiselle, L.Wei, G.Lewis, E. Paul, A. Lakhtakia, H. Donahue Abstract: Each year approximately 500,00 bone transplants are performed in the USA. While these procedures can be limb sparing, there are many associated complications such as poor integration of the graft bone. Native bone can impart many of the important characteristics of bone grafts, however, common processing techniques, necessary to decrease the chance of transmission of disease, have been shown to produce changes in the surface extracellular matrix and collagen fibers of bone, resulting in decreased osteoblastic cell differentiation and osteoconductivity.

We have tested the hypothesis that biomimetic resurfacing of bone grafts will increase osteoconductivity of the transplanted bone. Surface topography at the nano-scale level has been shown to regulate cell behavior, including osteoblastic differentiation. Therefore, we examined bone cell osteoblastic differentiation on bone grafts in vitro, and bone graft healing in vivo. The grafts were processed in a manner similar to allografts and then coated with nanotopographic films composed of either (i) Poly(L-Lactic Acid) (PLLA) using a polymer de-mixing process or (ii) Hydroxyapatite (HAP) using a physical vapor deposition process.

HAP is commonly used to coat implants for bone healing, and combining HAP coated implants with allograft bone results in improved healing after implant revision surgery. This is the first study to test the effectiveness of HAP coating on bones, with specific focus on the nanotopography of that coating and the effects on osteoblastic differentiation and osteointegration. Poster 12 _____________________________________________________________________ Characterization of the Size, Shape, and Drug Encapsulation Efficiency of PLGA Microcapsules Produced Via Electrojetting for Anticancer Agent Delivery P. Fattahi, A. Borhan, M. Abidian Abstract: Despite significant progress in the development of new chemotherapeutic agents and drug delivery methods for brain tumors, malignant gliomas (high grade brain tumor) remains deadly with a median survival period of only about a year. The high dosage of chemotherapeutic agents required for penetration through the blood brain barrier during chemotherapy not only kills cancer cells but also damages healthy tissues and causes adverse side effects. Hence, a major unmet challenge in the treatment of malignant gliomas is the development of effective and targeted local delivery of chemotherapeutic agents at the cellular level. Drug-loaded biodegradable microcapsules with high drug encapsulation efficiency and controlled shape and size are attractive candidates for a more precise control of anticancer agent delivery at the tumor sites.

Here, we report the results of a systematic study of the size, shape, and drug release profiles of Poly(lactic-co glycolic) (PLGA) microcapsules produced and loaded with the anticancer agent 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) using an electrojetting technique. We report production of BCNU-loaded PLGA microcapsules in the form of flattened microspheres, microspheres, and microfibers with significantly (1) higher drug encapsulation efficiency, (2) more tunable drug loading capacity, and (3) narrower size distribution than those generated using other encapsulation methods. Poster 13 _____________________________________________________________________ A Label-free Droplet-based Optofluidic Detection Device F. Guo, M. Lapsley, T. Huang Abstract: Analysis of chemical or biomolecular contents in a tiny amount of specimen significantly challenges biochemical studies and clinical diagnosis. We developed a droplet optofluidic interferometer for nanoliter liquid sample/reagent label-free measurement. Droplet generation, transportation, and refractive index detection function components were integrated into a single layer device

Materials Day 2013

18

through the common lithograph fabrication process. Using a single wavelength laser and a silicon photodiode for data collection, contents of individual droplets could be analyzed with a limit of detection (1.24x 10-4 refractive index units (RIU)), low variability (1.0 x 10-4 RIU), and small sample volume format (1nl per droplet). Taking advantages of low-cost, highly sensitive and label-free detection system and ultra-small sample volume requirement, our device would have potential for point of care clinical diagnosis. Poster 14 _____________________________________________________________________ Hybrid Conducting Polymer Hydrogel Nanofibers for Glucose Detection G. Kim, M. Abidian Abstract: Quantification of certain neurochemicals could be a useful diagnostic tool for the early detection of neurological disorders. In particular, monitoring changes in extracellular glucose concentration in brain may improve the diagnosis and therapy for diabetes mellitus and Parkinson’s disease. While studies have shown the feasibility of glucose detection using an enzyme-based amperometric biosensor, development of a glucose biosensor with higher sensitivity and longevity is still a challenge. Recently, we have developed a highly sensitive amperometric glucose biosensor using conducting polymer-hydrogel nanofibers with physically entrapped enzyme glucose oxidase (GOx). Sensitivity and longevity of the biosensor were improved with the incorporation of conducting polymer as an entrapping matrix of GOx. A potential of +700mV (Ag/AgCl reference) was applied for the detection of glucose.

The fabrication process includes electrospinning nanofibers from a solution containing poly(ethylene oxide) (PEO), poly(ethylene glycol) diacrylate (PEGDA), 1-Hydroxy-Cyclohexyl-Phenyl-Ketone (HCPK) and 10-25% wt. doped conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) on the surface of platinum electrodes. Glucose oxidase (GOx), an enzyme, which detects glucose, can easily be immobilized into conducting polymer-hydrogel composite nanofibers (PEO-PEGDA-PEDOT:PSS) during electrospinning. The nanofibers form a hydrogel scaffold during UV polymerization in the presence of a photoinitiator. GOx molecules embedded in the PEO-PEGDA-PEDOT:PSS hydrogel nanofibers immediately detect glucose molecules in phosphate buffered saline solution at low working potential of +700 mV applied.

The future goal of this work is to improve the longevity and stability of the developed biosensor for continuous in vivo monitoring of glucose in diabetic and Parkinsonian animal models. Poster 15 _____________________________________________________________________ Transcriptional Variations of a Bioelastomeric Adhesive T. Ozdemir, A. Francesh, Y. Nur, M. Demirel Abstract: Mimicking properties of biological materials such as reversible adhesion, fracture resistance, protective shielding, or structural integrity allow us to synthesize, design and fabricate new advanced materials with multi-functional capabilities. Materials properties of bioelastomers extracted from biological samples could vary heavily between sub species due to the differences in structure and composition. For instance bioelastomeric toe pads of geckos employs varying wet and dry adhesion but the morphologic features of toe pads evolved in a way to ease the adhesion of the geckos with their environment. The gain or loss of adhesiveness between different species shed light into not only the molecular structure but also the integration of the hierarchy of systems that serves at morphological length scales. Therefore understanding the functional transitions of the biomimetic systems could potentially help designing optimized materials resilient to environmental factors. A recently discovered bioelastomer, the squid ring teeth (SRT), shows multi-functional characteristics such as strong wet and dry adhesion, as well as recyclable and reusable bio-plastic potential which could be molded into any 3D geometry. This bioelastomer is promising for many medical, cosmetic and pharmaceutical applications ranging from surgical sutures, tissue engineering scaffolds and drug carriers. We showed that the mechanical properties of SRT show significant differences between the species within the same family. In addition the amino acid compositions of SRT protein also show differences especially in amino acid composition as well as sequence. Based on these results we hypothesized that the expression of SRT protein could vary between different squid species at the transcription and translational level. This study proposes to find an optimal functional sequence for recombinant production of the SRT protein as a promising multi-functional bioelastomer for biomedical applications. Poster 16 _____________________________________________________________________ Adhesion Mechanism of a Protein Melt A. Pena-F, B. Akgun, W. Zhu, H. Gao, Melik C. Demire Abstract: Natural elastomers made from protein extracts have received significant interest as eco-friendly functional materials for underwater adhesion. While some biological materials present interesting properties, they cannot be processed due to chemical cross-linking or thermal instability. However, a recently discovered bioelastomer (the sucker ring teeth SRT extracted from squid species) present thermomechanical properties similar to thermoplastic polymers, allowing the material to be molded into any 3D geometry. Exploiting this unique behavior in natural protein materials, we studied the pressure-induced adhesion mechanism of this thermo- reversible, recyclable and reusable bioelastomer as a potentially inexpensive, environmentally safe alternative to synthetic adhesives. The underwater adhesive is at least two orders of magnitude stronger than synthetic adhesives and ten times the strength of biological adhesives.

Materials Day 2013

19

Poster 17 _____________________________________________________________________ Metallomembranes: Exploring Transtion Metal/Lipid Complexes M. Poyton, X. Cong, A. Sendecki, P. Cremer Abstract: The interaction between transition metal ions and lipid bilayers is thought to play a key role in neurodegenerative diseases. However, the interaction of transition metals with specific lipids in lipid bilayers has essentially gone unstudied. Our lab has developed a novel fluorescence quenching assay to study the binding of transition metals to model lipid membranes. Upon binding to supported lipid bilayers, metals quench nearby fluorescent lipids. Using this method we have recently found that Cu2+ can bind to the lipids phosphatidylethanolamine (PE) and phosphatidylserine (PS) with nanomolar and femtomolar affinity, respectively. The affinity of Cu2+ to a lipid bilayer containing PE or PS is modulated by the concentration of these lipids in the membrane. The formation of these metal-lipid complexes are pH dependent and highly reversible. Poster 18 _____________________________________________________________________ Synthesis and Characterization of Biomimetic Citrate-Based Osteoinductive Composites R. Tran, C. Zhang, B. Banik, J. Brown, J Yang Abstract: Prior research has shown that bone is not only composed of a nanocomposite of collagen and inorganic minerals, but is also rich in citrate content. Citrate, the ionic conjugate base of citric acid, is historically known as an intermediate of the Kreb’s cycle for eukaryotic energy production, but studies have shown that a majority of the body’s citrate content is located in skeletal tissues playing large roles in metabolism, calcium chelation, hydroxyapatite (HA) formation, and regulating the thickness of bone apatite structure. Surprisingly, citrate has not been mentioned in most of the literature related to orthopedic biomaterials development in the past 30 years. The natural existence of citrate in bone hints that citrate should be considered in bone biomaterial design, and motivates us to develop the next generation of biomimetic citrate-based hydroxyapatite composites that can match the native composition of bone, provide adequate mechanical support, minimize inflammatory responses, quickly induce bone regeneration, and fully integrate with the surrounding tissue.

We have developed a new class of osteoinductive biodegradable citrate-based polymer blend HA (CBPBHA) composites based on our newly developed CUPE, POC, and HA. The discovery of CBPBHA composites bridges the gap in previous bone biomaterial designs in that the role of citrate molecules was inadvertently overlooked. Future studies will focus on further understanding the role of citrate in culture medium for bone stem cell differentiation and optimizing the citrate-content in polymer/HA composites for orthopedic applications. CBPBHA composites represent a new generation of bone biomaterials that address the critical issues such as inflammation, osteoinductivity, and osteointegration. The preliminary understanding on the role of citrates in culture medium and biomaterials is instrumental and it opens new avenues for future bone stem cell culture and bone biomaterial designs. Poster 19 _____________________________________________________________________ Active Bone-Crack Detection, Targeting, and Repair using Ion Gradients V. Yadav, J. Freedman, M. Grinstaff, A. Sen Abstract” Bone micro-cracks and fractures affect a large number of people worldwide and across ages. Current research is focused on promoting bone healing by delivery of a therapeutic agent to the bone via passive diffusion. These clinical treatments include systemic anti-resorptive or anabolic therapies, which are useful for general increase in mineralization and bone strength in patients. However, since bone diseases like osteoporosis vary in degree of degeneration at different skeletal sites, fractures of vulnerable areas like the hip, spine, and wrist are common even with preventative therapies. Moreover, mechanisms for active delivery of agents to target sites most at risk for fracture or of active degeneration remain elusive and are highly desired. In our study, we present the active detection of ex vivo human bone cracks and strategy for repair, based on the phenomenon of diffusiophoretic motion.

We describe a biological-synthetic hybrid colloidal micropump-based strategy for detection of bone lesions by utilizing the damaged matrix itself as both the trigger and the fuel. A crack in a mineral-rich material like bone generates ion-gradient driven electric-fields which can be utilized for active targeting and treatment. Bone is composed of collagen and a mineral matrix most closely resembling hydroxyapatite, which at physiological pH, undergoes hydrolysis as follows:

Ca10(PO4)6(OH)2 + 12H2O 10Ca2+ + 6H2PO4- + 14OH- A crack in the bone releases ions into the surrounding solution. The large difference in diffusion coefficients between the

cation (Ca2+) and the faster anion (OH-) [D(Ca2+) = 0.789x10-5 cm2s-1, D(OH-) = 5.273x10-5 cm2s-1, D(H2PO4-) = 0.959x10-5 cm2s-1] induces a local electric field oriented outwards. Charged moieties introduced in the system respond to this electric field undergoing diffusiophoretic motion. This strategy is utilized for targeting and repair.

Materials Day 2013

20

Poster 20 _____________________________________________________________________ Blood Plasma Biomarker Separation Using a MEMS Device Integrated with a Vertically Aligned Carbon Nanotube Membrane Y-T. Yeh, S. Trolier-McKinstry Abstract: We have developed a MEMS filtration device fabricated with patterned vertically aligned carbon nanotubes (VACNT) and polydimethylsiloxane (PDMS). The microfluidic channel wall of the droplet-shaped device is made of a VACNT forest in the dimension of 50 µm in height, ~107 counts/cm2 in density and 15 nm in single VACNT diameter. The VACNT is synthesized by aerosol based chemical vapor deposition on a patterned Fe catalyst thin film. The Fe catalyst is deposited on a silicon substrate and patterned by lift-off fabrication in droplet geometry. The top PDMS cover is fabricated by SU-8 molding technique with two fluidic access through holes, one inlet and one outlet. Oxygen plasma surface treatment is applied on both PDMS and VACNT to achieve permanent bonding and sealing. The dead-end filtration is performed in the assembled device. The inlet port is established as a sample reservoir. The outlet port is connected to vacuum source with a sample collection trap. The sample at the inlet reservoir is driven by vacuum source connected outlet and transported through the filtration membrane. The membrane is characterized to have permeability of ~1014 m2, porosity of ~99.6% and cut-off size of ~124 nm. The measured permeability and porosity match with the theoretical estimation by Darcy's model at the same order of magnitude. The cut-off size is estimated by combining flow resistance experimental data to a VACNT forest geometrical model, and later confirmed to be within the range of 110-140 nm with filtration experiments using fluorescently labeled nanoparticles of different sizes. The membrane is able to achieve high throughput nano-scale liquid filtration due to its high porosity and nanometer range cut-off size. Furthermore, we demonstrate the blood albumin measurement after plasma separation from human whole blood. The results show that plasma from the blood can be extracted and collected at outlet vacuum trap while the blood cells are blocked and confined at the enclosed droplet chamber. The measured blood albumin concentration matches with that measured after conventional plasma extraction by centrifugation. Poster 21 _____________________________________________________________________ Design and Synthesis of Thermally Stable Reagents and Paper-based Microfluidic Devices for Point-of-Care Diagnostics K. Yeung, S. Phillips Abstract: This poster describes strategies for designing point-of-care diagnostics that can be used in resource-limited environments. Diagnostics for this setting must be inexpensive, thermally-stable, and easy-to-use, as well as provide high sensitivity and selectivity for detecting analytes. The poster includes paper-based microfluidic devices and their application in point-of-care diagnostics, as well as the design of thermally-stable small molecule reagents that are capable of autonomously detecting trace chemical signals and then providing an amplified response (i.e., color, fluorescence, smell). Poster 22 _____________________________________________________________________ Novel Nanoparticle Contrast Agents for Multimodal Imaging Based on Near Infrared, Magnetic Resonance Imaging, and Photoacoustic Imaging X. Tang, D. Natale, M. Kester, S. Knecht, T. Neuberger, R. Tutwiler, J. Adair

Abstract: Imaging techniques using nanoparticle contrast agents have been studied for the early diagnosis of many human diseases and maladies, including cancer and internal trauma. The near infrared dye-encapsulated calcium phosphosilicate nanoparticles (NIR-CPSNPs), invented at Penn State, are a promising particulate-based imaging contrast agent within the near infrared range for deep penetration into body tissues. Since the earliest publication (Altinoglu, et al., ACS Nano, 2008), the NIR-CPSNPs have been used in vivo to detect and treat a wide variety of human cancers, including breast, pancreatic, osteosarcoma, and chronic myeloid leukemia. However, other nanoparticles have recently been developed and validated for first in man trials based on ferromagnetite nanoparticles that can provide better contrast for imaging techniques such as magnetic resonance imaging and computed X-ray tomography. Fe3O4 nanoparticles in the diameter ranges of 20 to 30nm and 50 to 150nm are highly crystalline with a magnetization approaching the theoretical limit of 85 emu/mg. They were prepared based on an aqueous synthetic route reported by Sumitomo and Matijevic (JCIS, 1980). For high-resolution medical visualization of the internal structures of the body, magnetic resonance imaging and computed tomography are widely used. The effect of the state of dispersion for the magnetite nanoparticles, a common magnetic imaging contrast agent, on magnetic resonance imaging has been tested at Penn State in the High Field MRI Lab. Moreover, the dye-encapsulated calcium phosphosilicate nanoparticles are also a useful platform for photoacoustic imaging. Ultrasound signals are detected as the result of the thermal expansion effect of calcium phosphosilicate nanoparticles after the absorption of radiation at the excitation wavelength of the encapsulated dye. The ultimate goal in the future is to realize multimodal imaging, including near infrared imaging, magnetic resonance imaging/computed tomography and photoacoustic imaging with a novel composite nanoparticle material.

Materials Day 2013

21

Poster 23 _____________________________________________________________________ Micromachined Magnetic Sensors G. Hatipoglu, F. Li, N. Goel, S. Datta, S. Tadigadapa Abstract: The biomedical imaging applications such as magnetoencephalography and MRI require magnetic sensors that are able to detect low magnetic fields emanating from human body that typically range from nanotesla to femtotesla. In this poster we present two different sensing approaches that have been developed to detect the low strength magnetic fields. First approach utilizes the magnetoviscous effect of ferrofluids, which is the phenomenon where the viscosity shifts occur in ferrofluids as a result of applied external magnetic field. The viscosity shifts are quantified and tracked in real time via shear mode bulk acoustic wave quartz micro-resonators (µ-QCR), and the whole device is exploited as a magnetic sensor. Real-time tracking of the emittance is exploited as a magnetic sensing mechanism to detect and quantify the low frequency, low strength magnetic fields. The initial results indicate a

minimum detectable field of 1.5 nT / Hz at 1Hz. Second approach utilizes an integrated magnetoelectric (ME) flexural gate transistor with nanotesla magnetic field detection sensitivity at room temperature. The device capacitively couples a Metglas (Fe85B5Si10) -based magnetostrictive unimorph micromechanical cantilever beam to the gate of an n-channel field-effect transistor. Using this sensor configuration, a sensitivity of 0.23 mV/μT and a minimum detectable field of 60 nT/√Hz at 1 Hz and 1.5 mV/μT and 150 pT/√Hz at the flexural resonance of the cantilever structure of 4.9 kHz were obtained. The results demonstrate a significant improvement in the thin-film ME sensor integration with standard CMOS process and open the possibility of monolithic magnetic sensor arrays fabrication for biomedical imaging applications. Poster 24 _____________________________________________________________________ Majd Lab: Cellular Biophysics and Nanotechnology Laboratory S. Park, C-F. Kuo, Y.Kang, S. Majd Abstract: In the Majd lab, we are interested in the principles underlying the function of cell membranes and applying these principles for the design and development of bio-inspired nano-scale systems that can specifically target diseased cells and deliver therapeutics to these cells.Our group employs a multidisciplinary approach, integrating principles from cell and molecular biology, biophysics, biomaterials, and micro/nano fabrication towards the abovementioned goals.To investigate the function of cell membranes, we develop model systems that closely mimic these membranes in size, composition, and function. We are currently applying cell-sized membrane-mimicking systems for studying multidrug resistance in cancer (cancer cell resistance against multiple chemotherapeutics). Towards the development of bio-inspired nano-scale systems for efficient delivery of therapeutics, we combine polymeric biodegradable nanoparticles with cell membrane-mimicking materials.We are currently exploring the application of these nano-delivery systems for targeted delivery of therapeutics to brain tumors while minimizing undesired side effects. Poster 25 _____________________________________________________________________ Preparation of Vesicles with Controlled Size and Composition as Cell Membrane Mimics Y. Kang, H. Wostein, and S. Majd Abstract: Liposomes are tiny spherical capsules with a lipid bilayer shell and an aqueous core and have been used in many applications including gene and drug delivery. Liposomes can be prepared in size scale of cells and with lipid and protein components that are found in natural cell membranes. These liposomes are referred to as giant proteoliposomes and closely mimic cellular membranes. They are, therefore, excellent model systems for studying processes that happen at the surface of cells such as the molecular events during the entry of pathogens and drugs into cells. Here we present a unique, simple, and versatile approach for producing uniformly sized giant proteoliposomes. This approach that combines the versatile technique of hydrogel-based microcontact printing and the commonly used technique of electroformation is efficient, low-cost, and doesn’t require any specialized equipment. The resulting liposomes are attached to the surface in an array format and can be used in this format for membrane studies. Alternatively, they can be easily detached from the surface to produce a large number of giant liposomes with functional proteins. This approach may further be applicable to produce giant polymerosomes that offer increased stability compared to liposomes. This method of production of giant liposomes can, hence, be useful in biomaterials, biotechnology, and biosensing applications as well as in the biophysical fundamental studies.

Poster 26 _____________________________________________________________________ Phase-field Simulation of Defect Transport and Resistance Degradation Behavior in Single Crystal BaTiO3 Y. Cao, J. Shen, C. Randall, L. Chen Abstract: A new phase-field model has been proposed which takes into account the non-periodical boundary condition based on the Chebyshev collocation algorithm to study the resistance degradation behavior of ferroelectric capacitors in the presence of ferroelectric polarization and elasticity. We consider both single domain and 90˚ domain wall structures in a thin film BaTiO3 single crystal orientated to the normal of the electrode plates (Ni) in a single parallel plate capacitor. The capacitor is subject to a dc bias

Materials Day 2013

22

either along the polarization direction or reverse to the polarization direction at 25oC. The local charge and the elasticity near the domain wall both affect the local distribution of ionic and electronic charge carriers. The polarization bound charges at the metal/ferroelectric interface are shown to play an important role in charge carrier transport and leakage current evolution in BaTiO3 capacitor Poster 27 _____________________________________________________________________ A FFT-based Elasto-viscoplastic Phase-field Model for Recrystallization L. Chen, J. Chen, Y. Ji, T. Heo, S. Bhattacharyya, R. Lebensohn, S. Mathaudhu, Z. Liu Abstract: A fast Fourier transform (FFT)-based elasto-viscoplastic phase-field model (PFM) is proposed for modeling recrystallization and grain growth of deformed polycrystalline systems. We solve the elasto-viscoplastic equilibrium equation during each step of temporal phase-field evolution. In contrast to all existing recrystallization models, a 3D FFT-based full-field formulation is employed to predict the inhomogeneous distribution of strain and stress fields during elasto-viscoplastic deformation of the polycrystal with rate sensitive crystal plasticity. This helps us to significantly enhance the computation, especially for the 3D cases. The proposed model is demonstrated by comparing the recrystallization kinetics with the theoretical Johnson-Mehl-Avrami-Kolmogorov (JMAK) model. Further, the effects of the deformed grain size and plastic deformation are investigated with the developed model. This study also gives us a new pathway to explore the evolution of 3D microstructures under elasto-viscoplastic deformation. Poster 28 _____________________________________________________________________ Phase-Field Simulation of Anisotropic Li Intercalation in LixFePO4 Nano-Particles L. Hong, L.-Q. Chen Abstract: Phase-field method is employed to model the bulk-diffusion-limited lithium (Li) intercalation process, in which the elastic energy determines the habit orientation of Li-rich/Li-lean phase boundary. To take into account the shape of a particle, the spectral smoothed boundary method is used. The anisotropic Li intercalation process with curved phase boundary is observed, and through the modulation of Li anisotropic mobility, the lithiated phases regulate their filling sequences of the Li channels. We show that promoting the growth of plate-like Li-rich crystallites through the increase of Li mobility along [001] is beneficial to the improvement of discharging speed of the LixFePO4 nano-particle electrode. Our simulations suggest that a LixFePO4 nano-plate with prominent {010} and {001} surface facets and the longest axis length along [100] is promising to show great mechanical stability and charging/discharging speeds. Poster 29 _____________________________________________________________________ Transport and Mixing of Materials into-and-out-of Dead End Pores A. Kar, T. Chiang, I. Ortiz, A. Sen, D. Velego Abstract: Achieving transport inside dead end pores is not currently possible with pressure driven mechanisms, which limits our ability to obtain material from these pores, or to put material into them. Here we show that the phenomenon of diffusioosmosis can be used to drive flows in dead end pores, and the flows can be used to sweep otherwise-trapped materials from the pore into a sink, or vice versa. These flows arise along the walls of the channel due to an imposed or self-generated salt gradient. We observe that tracer particles have a finite axial speed of roughly 50 µm/s, as well as a finite crosswise transport due to mixing inside these pores caused from the fluid flow. Using electrokinetic modeling along with independently measured system parameters, we find solid agreement between predicted speeds and our experimental data. The temporal nature of the salt gradients may explain some of the other phenomena like the LoSal waterflooding process and DNA translocation in solid-state nanopores. Poster 30 _____________________________________________________________________ Characterization and Constitutive Material Model Implementation for High-Strain-Rate Deformation Modeling with Finite Elements J. Schreiber, I. Smid, T. Eden Abstract: Modeling of high strain rate properties of dynamic systems is a very important area of research for many industrial and military applications. Currently, only a limited number of constitutive material models that explain these behaviors are pre-programmed into commercial finite element codes. This requires the use of user subroutines to predict how a part will fail. This work investigates the development, use, and comparison of user subroutines, versus the currently implemented constitutive models such as the Johnson-Cook, Zerilli-Armstrong, and MTS models found in finite element programs such as Abaqus CAE and ANSYS. Using data gathered from the Split Hopkinson Pressure Bar technique, these models are used to predict the failure of a ring constructed from AISI 4340 steel under explosive loading. The influence of mesh refinement and loading conditions are also investigated.

Materials Day 2013

23

Poster 31 _____________________________________________________________________ Calculation of Impurity Diffusion Coefficients in Mg Using First-principles Methods B-C. Zhou, S. Shang, Y. Wang, Z-K. Liu Abstract: As the lightest metallic structural materials, Mg alloys hold great promises to considerably reduce the weight of transportation vehicles and improve their fuel efficiency. Impurity diffusion coefficients are critical properties for Mg alloy design. However, experimental measurements of impurity diffusion coefficients in Mg are extremely difficult and scarce in the literature. In the present work, first-principles calculations based on Density Functional Theory (DFT) were used to calculate the full impurity diffusion coefficients for a large series of substitutional elements in hexagonal closed packed (hcp) Mg as a function of temperature using an 8-frequency model. Minimum energy pathways for impurity diffusion and the saddle point configurations during solute migration were calculated with the climbing image nudged elastic band method. Vibrational properties were obtained using Debye-Grüneisen model with input parameters directly calculated from first-principles. The recently developed PBEsol exchange-correlation (XC) functional was used in the present work, which is able to get good results on both vacancy formation energies and equilibrium properties. Excellent agreements of the calculated diffusion coefficients compared with available experimental data were obtained. The established diffusion database forms the foundations to accelerate the design process of high-performance Mg alloys in the context of Materials Genome Initiative. The computational methodology developed herein can be extended to efficiently predict diffusion coefficients in other crystalline materials. Poster 32 _____________________________________________________________________ Fluorination of Graphene, Gas Sensing on Carbon-based Materials, Proximity Effects of Graphene/Topological Insulators, and Spectral Analysis of Water/Metal-oxide Surface: Physics of Adsorption and Interfaces P. Aditya, M. DelloStritto, S. Liang, G. Yang, J. Sofo Abstract: Atomic structure at interfaces can have significant impact on macroscopic properties of materials and devices, and it is even more important at the nanoscale where surface effects become enhanced. We focus on developing theoretical models of systems where interfaces and adsorption play an important role. (1) The charge transfer processes between fluorine atoms and graphene determines the interactions and dynamics during the formation of fluorographene. This weakly bonded systems present a big challenge to our current ab-initio methods due to self-interaction errors. We set up a theoretical model to describe this charge transfer and guide improvements to its description at the ab-initio level. (2) Molecular adsorption on graphene and single-walled carbon nanotubes is the key process behind promising methods for gas sensing; their conductance changes upon exposure to ultra-low concentration of various molecules. Using the kinetic Langmuir model, we bridge the gap between the microscopic charge transfer mechanisms and the experimentally measured sensor responses. This model is used to guide the design of better sensors. (3) We combine graphene with topological insulators(TI). TIs are bulk insulators hosting exotic gapless surface states that are robust under a time-reversal invariant perturbation. A simple tight-binding model indicates that graphene on top of TIs will develop exotic proximity effects, such as cubic dispersion and non-trivial spin texture. We combine DFT calculations with a tight-binding model to study graphene-tetradymite (Sb2Te3,Bi2Se3 etc.) heterostructure. (4) The strong interaction between water and metal-oxides results in surface structures that can have applications to gas-sensing, dissolution, and other chemical processes on the surface. Of special interest is silica, which is important in many geochemical and industrial applications, and whose dissolution rate varies by orders of magnitude with pH and ion concentration. We use ab-initio calculations on a SiO2 nanoslit to investigate the microscopic aspects of competing theories of the silica dissolution mechanism. Poster 33 _____________________________________________________________________ Metals and Alloys for Electronics and Related Applications S. Mohney Abstract: This poster describes efforts to study and develop metals and alloys for electronics, optoelectronics, photovoltaics, microelectromechanical systems, and other applications. Often the metals are in the form of thin films, and they may be prepared by physical vapor deposition, electrochemical deposition, or atomic layer deposition. Combinatorial techniques are sometimes applied to refine the composition of an alloy or the thickness of a layered metallization stack. The electrical resistance of the metals and alloys, or the resistance at the interface between the metals and the rest of a semiconductor device, is engineered through materials selection and judicious processing. Stability against high temperature degradation, extreme environments, and electromigration are considered. Examples of projects with relevance for integrated circuits, solar cells, automotive packaging, and space exploration are described. Poster 34 _____________________________________________________________________ Center for Dielectrics and Piezoelectrics C. Randall Abstract: The dielectric components industry is undergoing its biggest transformation of the last 30 years, due in large part to: i) the emergence of wide-bandgap semiconductor platforms (e.g. SiC for dc-ac power inverters), ii) shifting trends in energy storage and

Materials Day 2013

24

power sources for the transportation sector and power-supply industry, iii) an increasing need to integrate energy storage, management and transduction components into unconventional packages (e.g. flexible electronics) and iv) the need to integrate functional materials into conventional microfabrication process flows. Exciting technology and product opportunities emerge from these changes, but these can only be realized through innovation in materials design, processing, and integration across a broad array of technology platforms. A diverse team of faculty from North Carolina State University (NCSU) and the Pennsylvania State University (PSU) is positioned to meet these scientific and technical challenges by studying the fundamental physical principles of electrostatic energy storage and transduction common to a broad cross-section of dielectric materials, while advancing processing and integration sciences that translate materials discovery into tangible technology opportunities.

The Center for Dielectrics and Piezoelectrics (CDP) I/UCRC is the product of a shared vision developed by the participating faculty at NCSU and PSU and numerous industrial participants from the dielectrics and piezoelectric industries. The proposed CDP is a response to the new basic-research demands of the highly diversified and “reinvented” global capacitor industry. More generally, however, the core research thrusts of the CDP are designed to appeal to a much broader array of innovative companies, who have significant needs for advanced dielectrics and piezoelectrics in numerous applications and products. The technical, management and educational structure of the proposed I/UCRC described herein will enable the CDP to achieve its overarching goals to: • Improve the fundamental understanding of dielectric and piezoelectric materials and their device integration • Create transformative dielectric and piezoelectric materials that support innovative technology advancements; transfer this

technology to CDP members in support of new products and processes • Educate graduate students and postdoctoral scholars that become successful leaders of the research community and create

immediate technical impact with a highly diverse team • Develop unique measurement, characterization, and modeling infrastructure to support the industry • Catalyze strategic coupling with other I/UCRCs to expand scientific impact and value for members • Become the internationally recognized center of excellence in the science, technology, and integration of capacitive and

piezoelectric materials Poster 35 _____________________________________________________________________ Low Temperature Deposition and Fabrication of ZnO TFTs for Flexible Electronics H. Li, J. Ramirez, M. Lee, H. Fok, T. Jackson Abstract: For low-cost, large-area electronics, especially electronics on flexible substrates, a robust, low temperature process is highly desirable. Oxide semiconductors have attracted significant research and manufacturing effort in recent years. Among oxide semiconductors, ZnO is of particular interest because of its compositional simplicity and wide range of available deposition techniques. Plasma enhanced atomic layer deposition (PEALD) provides a low temperature (<200 °C) deposition approach which is suitable for thin film electronics fabricated on inexpensive flexible substrates such as polyimide. Spin spray solution deposition can provide even lower temperature materials deposition (<100 °C).

Polyimide films are convenient substrates for flexible circuit fabrication. For our device processing, a polyimide film was prebaked at 200 ̊C and laminated onto a glass substrate with silicone gel to provide a rigid carrier for ease of fabrication. Next, a 100 nm thick chromium gate layer was deposited by ion beam sputtering onto the polyimide substrate and patterned by wet etching. After gate patterning, PEALD was used to deposit a 50 nm thick Al2O3 film from trimethylaluminum (TMA) and CO2, and a 10 nm ZnO film from diethylzinc (DEZ) and N2O, both at 200 ̊C. The ZnO was then patterned by wet etching in dilute HCl and the Al2O3 was patterned by wet etching in hot (80 ̊C) phosphoric acid. Titanium was sputtered and patterned by lift off to form source and drain to complete the thin film transistors (TFTs). Finally, devices were passivated using 30 nm of Al2O3 deposited by atomic layer deposition (ALD) from TMA and water at 200 ̊C. PEALD ZnO TFTs on flexible substrates typically have electron mobility of ~20 cm2/V⋅s. The temperature dependence of ZnO TFTs has been studied and reported on by Mourey, Zhao, and Fok [3,4]. The drain current shift with temperature of the ZnO TFTs allows them to be used as temperature sensors. Fabrication on a thin, polymeric flexible substrate provides mechanical and thermal characteristics similar to biological tissue and allows simple temperature measurement. Biasing a ZnO TFT with 200 Cm channel width and 20 Cm channel length at a fixed drain current of 20 μA and a gate voltage of 6 V, and using the drain voltage (VDS) as the sensor output, we obtained a roughly linear temperature dependence relationship with a slope of about 10 mV/ ̊C in the temperature range of 23 ̊C to 45 ̊C. ZnO TFT temperature sensor arrays with 16 x 16 sensing elements have been fabricated and tested on flexible substrates. Poster 36 _____________________________________________________________________ On-Axis Growth of SiC Epitaxial Layers by Halide CVD for High Voltage Power Devices M. Fanton, D. Snyder, B. Weiland, R. Cavalero, K. Trumbull, G. Pastir Abstract: Growth 50-200um thick SiC epitaxial layers was accomplished on 100mm diameter 4H-SiC substrates using high temperature halide chemical vapor deposition (HCVD). Deposition took place on the Si-face of N-doped substrates oriented within 0.1° of the <0001> direction. On-axis growth is made possible by the use of growth temperatures of 1900-2000°C, which greatly increases surface adatom mobility. The Si and C source materials were SiCl4 and CH4 respectively in a mixed Ar/H2 carrier gas. Growth rates ranged from 25-50um/hr. The impact of growth conditions on dislocation densities and x-ray rocking curve peak widths

Materials Day 2013

25

will be discussed. The nitrogen concentration in the epitaxial layers was typically 1-5x1015 atom/cm3. The surface morphology of the films show typical spiral growth hillocks common in bulk growth of SiC. For device fabrication, surfaces with an average roughness of 0.2nm were achieved by post-growth chemi-mechanical polishing. The performance of Schottky diodes fabricated from thick epitaxial layers will be outlined in the context of achieving blocking voltages exceeding 5kV. Poster 37 _____________________________________________________________________ Bulk Ionic Conductivity of Glass and Glass-Ceramic Lithium Thiophosphate Solid Electrolytes for Solid-state Batteries & Electrochemical Capacitors S. Berbano, M. Mirsaneh, M. Lanagan, C. Randall Abstract: Lithium solid electrolytes are important for safe energy storage and have the possibility to operate at higher voltages than liquid electrolytes. Solid electrolytes with high ionic conductivity are important to minimize the equivalent series resistance of solid-state batteries and electrochemical capacitors. To maximize the ionic conductivity, it is important to consider the relative impact of an optimized microstructure, phase assemblage, composition, and density.

Mechanically milled powders of the compositions x Li2S + (1-x) P2S5 (mol fraction), x = 0.70, 0.75, and 0.80, were cold-pressed (~ 75% dense) and pressed near their glass transition temperatures (~ 95% dense) at constant pressure. Density and impedance spectroscopy measurements suggest that ionic conductivity is improved by increasing the bulk conduction volume rather than by increasing the surface area. Higher density compacts had higher ionic conductivity with little change in the activation energy for conduction in a given composition. Impedance spectroscopy characterization on dense, crystallized x = 0.80 samples below room temperature revealed lower ionic conductivity when heated > 350oC. It is possible that bulk lithium loss (oversintering) at high temperatures limited the improvement in ionic conductivity from crystallization in glass-ceramics heated > 350oC. General differences between the nature of ionic conduction in oxides and non-oxides & amorphous and crystalline materials are discussed Poster 38 _____________________________________________________________________ Synthesis of Tungsten Diselenide Thin Films P. Browning, S. Eichfeld, K. Zhang, Y-C. Lin, C. Lee, G. Bhimanapati, L. Hossaine, J. Robinson Abstract: Two-dimensional transition metal dichalcogenide (TMD) materials have been the subject of great interest in recent years due to their many intriguing properties including a transition from an indirect to direct band-gap upon movement to a single atomic layer of the material and large room temperature photoluminescence. While much work has been performed on the study of the TMD MoS2, many investigations are still needed to understand the synthesis and properties of other TMD systems. Our group has successfully synthesized tungsten diselenide by oxygen replacement with selenium through both metal-organic CVD and selenium vapor flow methods. Films produced using these methods are fully continuous with roughness less than 0.3 nm. Interestingly, final film morphology has been found to be extremely similar to that of the oxide prior to selenization, suggesting generation of high quality oxide films can produce high quality tungsten diselenide films. We have also investigated the thermal stability of tungsten diselenide and its potential integration with graphene for the development of future two-dimensional heterostructures. Poster 39 _____________________________________________________________________ Conjugated Block Copolymer Photovoltaics with near 3% Efficiency through Microphase Separation C. Guo, Y-H. Lin, M. Witman, K. Smith, C. Wang, A. Hexemer, J. Strzalka, E. Gomez, R. Verduzco Abstract: Organic electronic materials have the potential to impact almost every aspect of modern life including how we access information, light our homes, and power personal electronics. Nevertheless, weak intermolecular interactions and disorder at junctions of different organic materials limit the performance and stability of organic interfaces and hence the applicability of organic semiconductors to electronic devices. Here, we demonstrate control of donor-acceptor heterojunctions through microphase-separated conjugated block copolymers. When utilized as the active layer of photovoltaic cells, block copolymer-based devices demonstrate efficient photoconversion well beyond devices composed of homopolymer blends. The 3% block copolymer device efficiencies are achieved without the use of a fullerene acceptor. X-ray scattering results reveal that the remarkable performance of block copolymer solar cells is due to self-assembly into mesoscale lamellar morphologies with primarily face-on crystallite orientations. Conjugated block copolymers thus provide a pathway to enhance performance in excitonic solar cells through control of donor-acceptor interfaces. Poster 40 _____________________________________________________________________ Integrated Dielectric Materials for Electronics M. Lanagan Abstract: Dielectric materials (i.e. materials that store and dissipate electrostatic energy) have culminated in the development of: flexible glass dielectrics; the use of ceramic resonators for enhanced magnetic resonance imaging (MRI) systems; and new, high energy dielectrics and components that are critical for pulse power and power distribution systems. Breakdown strength, along with dielectric constant, determines how much energy can be stored in an insulating material before it fails and begins to conduct electricity. A bulk glass with high breakdown strength and high dielectric constant is an ideal candidate for the next generation of

Materials Day 2013

26

high energy density storage capacitors to power more efficient electric vehicles, as well as other portable and pulsed power applications. Additional research and development activities have combined dielectric theory, electromagnetic simulation, and experimental research to show how symmetry and resonance concepts influence wave propagation in electromagnetic “metamaterials,” i.e. materials that have been deliberately tailored and engineered to have properties that may not be found in nature. Simulations and designs of electromagnetic field distributions in coupled ceramic resonator systems have led to the creation of ceramic resonator geometries that have been incorporated into MRI systems for imaging samples such as Zebrafish. Poster 41 _____________________________________________________________________ Advanced Electroactive Materials and Devices Q. Zhang Abstract: We show in this poster several recent breakthroughs in our laboratory in developing advanced electroactive polymer and nanocomposites and their applications for energy conversion and energy storage: (i) the giant electrocaloric effect (ECE), i.e., large temperature and entropy changes, near room temperature in ferroelectric materials and cooling devices based on them; (ii) high energy density and power density ultracapacitors based on nano-porous graphene with controlled nano- morphology; (iii) high energy density capacitors with energy density > 25 J/cm3 with low dielectric losses; (iv) room temperature chip-scale ultra-sensitive magnetic sensors, integrating magnetoelectric effect with advanced system design. Poster 42 _____________________________________________________________________ Structure-property Relationship for SnS Thin Films and Single Crystal Material: Study of the Optoelectronic Properties of SnS for Photovoltaic Applications M. Horn , J. Brownson , A. Cröll, T. Songfrei, C. Giebink, S. Choi , Research team: Horn-Brownson Research Group Abstract: SnS has potential for 20% efficient solar cells based on its optoelectronic properties. Research groups around the world are investigating SnS via various deposition methods and heterostructures for thin film solar cells. The maximum achieved efficiency has yet to reach 3% despite the promising properties of SnS. The Horn-Brownson research group is investigating the optoelectronic sputtered SnS thin films and single crystal SnS acquired from University of Freiburg. Sputter deposition offers a wide range of parameters to tailor the material properties and yield a variety of crystalline quality. X-ray diffraction (XRD) patterns and scanning electron micrographs show stark differences in crystallographic orientation and morphology respectively, depending on the deposition conditions. Adjusted deposition parameters include Ar chamber pressure, target power, substrate-to-target distance and substrate temperature. Recent results show promising material for highly oriented dense thin film material, suitable for integration into devices. Absorption coefficients of these films are >105 cm-1 above the band gap. Spectroscopic ellipsometry is utilized to determine the optical constants of SnS via robust modeling methods. Rietveld analysis of XRD patterns shows multiple phases in many SnS thin films, which has poor implication for devices. Infrared spectroscopic ellipsometry will be utilized to confirm crystal structures identified from XRD patterns via bond lengths and compare to the single crystal sample. The research is contributing to develop the structure-property relationship for thin films relative to single crystal SnS.

Poster 43 _____________________________________________________________________ Nature Inspired Optimization of Broadband Absorbers, Mirrors, and Metamaterials for the Infrared J. Bossard, Z. Jiang, L. Lin, S. Yun, X. Wang, D. Werner, T. Mayer, Z. Liu Abstract: Single and multilayer planar metallodielectric metamaterials are being synthesized, fabricated, and characterized for infrared applications. These planar devices form absorbers, mirrors, and metamaterials and are optimized by a genetic algorithm (GA) to have a wide field of view (FOV) and a broad bandwidth in order to meet practical design requirements. Over the last few years there has been increasing interest in metamaterials research because of the exciting applications made possible by refractive index engineering, including flat near- and far-field focusing lenses, artificial magnetic mirrors, electromagnetic cloaks, and other transformation optics devices. The broad bandwidth metamaterials presented here are advancing the state-of-the art in metamaterials research. In this poster, we report on the successful design and experimental verification of several planar metamaterials and absorbers synthesized using GA techniques. Poster 44 _____________________________________________________________________ Templated Hydrogenated Amorphous Silicon Conformal Coatings T. Day, R. He, N. Healy, A. Peacock, P. Sazio, J. Badding Abstract: Hydrogenated amorphous silicon (a-Si:H) is one of the most technologically important semiconductors. The significant obstacle in producing a-Si:H from its hydride precursor, silane, is to surmount the kinetic barrier to decomposition at low temperature in order to incorporate sufficient hydrogen into the material. Traditionally, a-Si:H is produced via chemical vapor deposition (CVD). Conventional CVD methods require elaborate equipment to activate the reactants, whereas our high pressure CVD (HPCVD) process utilizes elevated precursor pressure to induce the decomposition of silane.

Materials Day 2013

27

The HPCVD technique allows for conformal coating of extreme aspect ratio structures by altering the aspects of the decomposition of precursor molecules into reaction products, such as chemical kinetics and thermodynamics, reactant flow, nucleation and growth, and surface chemistry. The resulting a-Si:H is atomically smooth and exhibits excellent materials properties. Additionally, a-Si:H can be doped with the introduction of dopant precursors into the reaction mixture, which enables the fabrication of a-Si:H solar cells in novel geometries.

Furthermore, the HPCVD technique has been adapted to produce conformal a-Si:H coatings in two- and three-dimensional templates. The reactor geometry is a critical factor for conformal film deposition rather than particle growth at high pressure. Due to the elevated pressure and decreased mean free path, the silane precursor is able to infiltrate templates with nanoscale features. The ability to infiltrate precisely doped silicon into confined, ordered templates gives rise to opportunities for new physics and material properties. Poster 45 _____________________________________________________________________ Light Trapping Schemes for Enhanced Light Absorption S. Hall, T. Mallouk Abstract: Thin film silicon solar cells are inexpensive but they do not absorb sunlight efficiently. We are investigating various light trapping schemes in order to increase the light harvesting efficiency of thin film photovoltaics. Recently we have proven experimentally and theoretically that multiple surface plasmon polariton waves can be excited at the interface of a metal and one dimensional photonic crystal. Such structures excite multiple s- and p-polarized SPP modes, which contribute to enhanced broadband absorption. We are currently investigating methods to integrate our multi-plasmonic structures into photovoltaic devices. Lastly, we are investigating the effect of dielectric nanostructures on the light harvesting efficiency of tandem photovoltaics. Poster 46 _____________________________________________________________________ Dielectric and Piezoelectric Properties upon Lateral Scaling of PMN-PT Films for Logic R. Keech, S. Shetty, S. Trolier-McKinstry, D. Newns, M. Copel, G. Martyna, T. Shaw, T. Theis Abstract: A fast, low power, transistor-type switching device has been proposed as a potential CMOS replacement for computer logic. In this technology, called piezotronics†, piezoelectric and piezoresistive materials are employed in a stacked sandwich structure of nanometer dimension. Actuation of the piezoelectric material results in a pressure induced insulator-to-metallic transition in the electrical conductivity of the piezoresistive material, turning the switch on from the normally off state. Of particular interest to this program is the functionality of the high aspect ratio piezoelectric 70Pb(Mg1/3Nb2/3)O3-30PbTiO3 (PMN-PT) component. Dense PMN-PT films of approximately 350 nm in thickness were made by chemical solution deposition using a 2MOE solvent. These films were phase pure and strongly {100} oriented by XRD with dielectric constants exceeding 1400 and loss tangents of approximately 0.01. The films showed slim hysteresis loops with remanent polarizations of about 10 μC/cm2 and breakdown field of over 1500 kV/cm. Fully clamped films exhibited large signal strain of approximately 1%, with a d33,f coefficient of approximately 90 pm/V. By laterally subdividing the blanket PMN-PT film into smaller driving pixels, the piezoelectric response is declamped from the substrate while reducing footprint of an individual piezotronic pixel. Reactive ion etching (RIE) has been employed to pattern features in the PMN-PT film down to one micron in spatial scale with vertical sidewalls. Upon lateral scaling, an increase in both small and large signal dielectric properties has been observed, including an approximate 50% increase in permittivity in PMN-PT structures with 1 μm wide features. A modified Mirau single beam interferometer is currently being built at Penn State University to accurately measure the evolution of the piezoelectric properties as the films are laterally subdivided.

† Reference: D.M. Newns, B.G. Elmegreen , X.-H. Liu, and G.J. Martyna, “The piezoelectronic transistor: A nanoactuator-based post-CMOS digital switch with high speed and low power”, MRS Bulletin, 37, 1071 [2012 ]. Poster 47 _____________________________________________________________________ Electric-Field-Assisted Assembly of 2D Sheets to Form Field-Effect Transistors S. Levin, J. Li, D. Sun, D. Vaughn II, M. Bresnehan, J. Robinson, R. Schaak, T. Mayer

Abstract: Solution synthesized GeSe and SnSe microsheets were controllably placed onto a silicon substrate using electric-field assisted assembly. Using top-down fabrication methods following the assembly, field-effect transistors were fabricated from these particles. Both the GeSe and SnSe particles were found to be lightly p-type doped semiconductors. Using a sequential assembly process, stacked heterostructures of GeSe and SnSe were made, with the SnSe preferentially assembling at the edge of the GeSe sheets. This result was confirmed with simulation showing high field gradients forming at the particle edges. Additionally, sheets of graphene and hexagonal boron nitride were assembled with electric-field assisted assembly. Both atomic force microscopy (AFM) and Raman showed no obvious damage to the films after assembly. This assembly technique can be used to make stacks of different 2D materials in order to make novel devices.

Materials Day 2013

28

Poster 48 Light Manipulation Using Plasmonic Nanoparticles A. Panaretos, F. Namin, and D. Werner Abstract: One of the greatest challenges in modern nanophotonics technology is the development of nanodevices that allow light manipulation in a fully controlled manner. A characteristic example of such a structure would be an optical nanoantenna that exhibits tunable or reconfigurable radiation and scattering properties. Similar to their radio frequency and microwave counterparts, nanodevices could be loaded by nanocircuit elements in order to enable their tunable or reconfigurable operation. Here, we present several novel nanostructures comprised of plasmonic nanoparticles that can manipulate light in a fully controlled way, which we have developed within IRG4. In the first part of this poster it is demonstrated how plasmonic core-shell particles can be utilized to realize tunable optical nanocircuits. First, the feasibility of tuning the optical response of a dipole nanoantenna using plasmonic core-shell particles is demonstrated. Secondly, it is demonstrated that core-shell particles can function as tunable, wavelength dependent nanoswitches that are robust and can be easily synthesized using standard nanofabrication techniques. The second part of the poster will demonstrate how near-field enhancement can be achieved via gold nanosphere arrays based on quasicrystalline aperiodic geometries. Aperiodic nanoparticle arrays provide much larger local field enhancements compared to periodic ones. This is of particular interest in engineering surface-enhanced Raman scattering (SERS) substrates, since Raman enhancement is proportional to the fourth power of the near-field enhancement. Furthermore, due to their higher order rotational symmetry, field enhancements show much less dependence on the polarization of the incident radiation. Additionally, in the same part of the poster it is demonstrated how these aperiodic arrays of gold nanospheres can function as wideband absorbers. Poster 49 _____________________________________________________________________ ZnO Thin Film Electronics for Circuits Anywhere I. Ramirez, K. Sun, Y-C. Li, Y. Goh, T. Jackson Abstract: Oxide-based semiconductors have rapidly developed in recent years for thin-film transistor applications. These materials are of interest because their low deposition temperature, high mobility, and good electrical stability make them an attractive alternative to amorphous silicon in many large-area thin film electronic applications. We have developed a process for depositing high quality stable oxide films at low-temperature (200 °C) using plasma-enhanced atomic layer deposition (PEALD). The enhanced performance and electrical stability allowed us to build fast ZnO-based circuits on glass and flexible substrates. Discrete TFT and circuit models have been developed to further understand the devices. Poster 50 _____________________________________________________________________ Computationally-aided Design of Li-ion and Fluoride-ion Batteries for Facile Ion Transport H-S. Shiau, M. Janik, R. Colby Abstract: Ionomers offer significant advantages as polymer electrolytes in Li-ion batteries. However, current ion conductivities are roughly 100X too small for practical applications. The fraction of conducting ions is thought to be low, indicated to be on the order of 10-4 by dielectric spectroscopy, suggesting further optimization towards promoting dissociation of the anion-cation interaction could enhance conductivity. A quantummechanical investigation on Li poly(ethylene oxide)-based ionomers was performed in the cluster-continuum solvation model. Predicted concentrations of Li+-conducting states are compared among a series of anions to indicate favorable features for selection of an optimal Li+-conducting ionomer; the perfluorotetraphenylborate anion maximizes the conducting positive triple ion population among the series of anions considered.

In order to boost the conducting ion mobility, we investigate the Li+ conduction mechanism by exploring the Li+ potential energy surface in sulfonated ionomers, and specifically the role of transient positive triple ions (Li+A-Li+) in the conduction process. This triple ion conduction mechanism explains a significant jump of the Li+ mobility experimentally observed in high ion-content ionomers. As the ion content increases, ion aggregation is more likely to occur and decreases both the conducting ion fraction and ion mobility. Instead, chain-like aggregates (ion chains) can prompt the charge conduction much faster than the ion diffusion (super-ionic conduction). A molecular level analysis of the dissociation/association of ion chains is critical to determine the activation barrier between the trapped and conducting states for the super-ionic conduction.

The potential applications of anion exchange membranes (AEIs) for energy storage and conversion have prompted the study of ion conduction in AEIs. Ammonium salts were the first cations investigated in hydroxide exchange fuel cell membranes. Alternate salts such as phosphonium and imidazolium have attracted increasing attention. From our result, the differences in the electronic structure make tetraalkyl phosphoniums quite distinct from ammoniums, causing differences in ion aggregation, glass transition temperature (Tg) and chemical stability. The phosphonium ionomers with F- anion display conductivity as high as 10-6 S/cm, which makes our phosphonium ionomers potential electrolyte separators for novel fluoride-ion batteries.

Materials Day 2013

29

Poster 51 _____________________________________________________________________ Carbon Nanofiller Modified Electroactive Polymers N. Sigamani, Z. Ounaies Abstract: Both ionic and electronic electro active polymers (EAPs) have shown great potential as actuators. Despite the many advantages of electronic EAPs such as light weight, good energy densities and high bandwidth, there are major obstacles facing their transition to application. Notably they require high actuation voltages, have low blocked stresses and low operating temperatures. The goal of this research is to investigate the electrical, mechanical, and dielectric properties of EAPs, modified using different types of carbon nanofillers. As a first step, PVDF-based polymer nanocomposites were prepared using graphene oxide (GO) and reduced GO to study the effect of these nanofillers on the mechanical, electrical and dielectric properties. The change in microstructure and crystallinity due to presence of these nanofillers is also studied. The polarization and the actuation response of the films were compared to the pristine polymers.

Previous research in our group showed that SWNT-based PVDF nanocomposites exhibit an electrostrictive response; however, due to the resulting high electrical conductivity and dielectric loss, their operating voltage is very limited. Hence, in this research, use of co-fillers is explored, namely single wall carbon nanotubes (SWNT) and graphene oxide (GO), in PVDF-based co/terpolymers with the goal of optimizing electromechanical response while keeping the dielectric loss low. The nanofillers were chemically modified to improve the interaction between them. Electrical conductivity of the nanocomposite is controlled by varying the ratio of SWNT/GO, which directly impacts voltage breakdown. The electromechanical actuation response of the hybrid films in response to electrical field is thoroughly investigated as well. In addition, the effect of the presence of hybrid SWNT/GO on the morphology of PVDF-based polymers and the mechanism driving this actuation are investigated and discussed.

Orientation of the co-fillers in the polymers is studied by mechanically stretching the hybrid nanocomposites and assessing the resulting change in morphology as well as the change in the electromechanical response. The increase in the dipolar relaxation strength and the remnant polarization, which directly relate to the electromechanical actuation response, are thoroughly studied before and after stretching. Poster 52 _____________________________________________________________________ Recent Developments on High Performance Piezoelectric Crystals S. Zhang, Z. Shen, Y. Tang, T. Shrout Abstract: Piezoelectric materials lie at the heart of electromechanical transducers. Applications include actuators, medical ultrasonic imaging and high intensity focused ultrasound (HIFU), underwater sonar, non-destructive evaluation (NDE), resonators, pressure sensors and accelerometers to name a few. The piezoelectric coefficient (dij), electromechanical coupling (kij) and dielectric permittivity (er) are the most important parameters that determine device performance. In addition, piezoelectric materials that can function at extreme temperatures without failure are desired for structural health monitoring and/or nondestructive evaluation of the next generation turbines, more efficient jet engines, electrical and nuclear power plants. The operational temperature range of these smart transducers is limited by the sensing capability of the piezoelectric material at elevated temperatures, increased conductivity and mechanical attenuation, and variation of the piezoelectric properties with temperature. Relaxor-PbTiO3 single crystals have been extensively studied due to their ultrahigh piezoelectric coefficients, d33s >1500pC/N and electromechanical coupling factors k33s >90%, however, their usage temperature range is limited by the low ferroelectric phase transition TRTs. Generally, nonferroelectric piezoelectric single crystals possess low sensitivity, falling in the range of 1-20pC/N. The ReCa4O(BO3)3 (ReCOB) oxyborate crystals and ordered langasite crystals have attracted considerable attention for ultrahigh temperature sensing applications, due to the absence of phase transitions prior to their respective melting temperatures, being on the order of 1300-1500oC, and their ultrahigh electrical resistivity at elevated temperature make them ideal candidates for ultra-high temperature sensing applications.

Poster 53 _____________________________________________________________________ Ultralow Resistance Ohmic Contacts to III-V and III-N Semiconductors M. Abraham, W. Choi, S-Y. Yu, S. Mohney Abstract: Ohmic contacts with extremely low specific contact resistances and carefully controlled morphologies are required for III-V digital logic, communications, and solid-state lighting. Here we report our experimental results for contacts to the semiconductors InGaAs and GaN. Our fabrication processes involve novel surface preparation and passivation techniques, in addition to optimized in situ solid-state regrowth schemes. Record low specific contact resistances have been achieved on lightly doped n-type InGaAs. Poster 54 _____________________________________________________________________ Growth of High Performance Oxide Thin Films Using Low Energy Growth Techniques C. Eaton, R. Haislmaier, H. Zhang, L. Zhang, Y. Zheng and R. Engel-Herbert Abstract: The growth of high quality thin films is a mandatory prerequisite to continue device miniaturization and performance enhancement in the field of electronic devices, ranging from sensors and detectors over actuators to memory and logic elements. Thin

Materials Day 2013

30

film deposition techniques, such as chemical solution and chemical vapor deposition as well as various physical vapour deposition techniques have been widely applied and polycrystalline films have been grown with properties affected by their microstructure. Precise stoichiometry control during film growth has proven challenging for the individual growth methods, in particular when applied to complex oxide thin films. Both factors, microstructure and stoichiometry, can fundamentally limit the film quality, and structural and chemical dissimilarities with conventional semiconductors, such as Si, render the integration of functional oxide thin films with established semiconductor technology platforms challenging.

Our research efforts are focused on developing novel growth strategies to enable electronic-grade oxide thin films. We capitalize on a hybrid growth approach by combining molecular beam epitaxy (MBE) and metal-organic chemical vapor deposition (MOCVD). Excellent material quality with defect concentrations comparable or lower than single crystals has been demonstrated. SrTiO3 with record-high electron mobility at low temperatures and doping level control down to the parts per million level evidence the film quality grown by hybrid MBE. The growth of the correlated metal SrVO3 with a room temperature conductivity that is on par with Pt has been developed, making it attractive as transparent conducting oxide. The epitaxial integration of perovksite oxides with Si using hybrid MBE has been successfully demonstrated.

We further have expanded our growth capabilities towards an atomic layer deposition (ALD) reactor that allows investigating the decomposition and wetting behavior, as well as quantifying sticking coefficient of MO molecules that are of relevance for both, hybrid MBE and ALD growth processes. The ALD reactor can be operated in the laminar and viscous flow regime, is equipped with an in-situ heated quartz crystal monitor and a differentially pumped quadrupole mass spectrometer, and allows supplying sub-monolayer doses of MO precursors, enabling quantitative experiments to characterize thin film growth processes relying on MO precursor. Poster 55 _____________________________________________________________________ Novel Optical Microsensing Devices P. Edwards, C. Yang, N. Mehta, C. Janisch, C. Zhang, Z. Liu Abstract: Miniaturization of devices and platforms is driving the current trend of sensors in electronic or optical devices. Miniaturized systems capable of sensing, detection, and manipulation provide vital analytical tools in biotechnology and biomedicine. In particular, here we discuss three novel optical devices -- an inexpensive, sensitive and compact optical spectrometer; an opto-electronic nano-tweezer, and micro-cavity-enhanced Raman spectroscopic system.

There is a growing need for development of cost-effective and miniature spectrometers that can be potentially integrated with portable electronics devices such as mobile phones and laptops. To reduce the size and cost of portable spectrometers, we propose a design using a hybrid grating-Fresnel optical diffractive element - G-Fresnel, which is fabricated by using polydimethylsiloxane (PDMS)-based soft lithography. Our prototype spectrometer based on G-Fresnel has a sub-nanometer resolution, whereas theoretical simulations show that a spectral resolution of approximately 1 nm can be potentially achieved with a millimeter-sized G-Fresnel. A miniature spectrometer integrated with mobile phone can potentially enable chemical sensing and even point-of-care testing. Opto-electronic nano-hand - i.e. nano-tweezers with two or more finger manipulators is a micro-manipulation platform we are developing which can grip, translate, and rotate a nano-object. Moreover, it can also be used to probe the properties of individual nanoscale object in situ through electronic measurement and/or optical spectroscopic characterization. In our nano-hand, photonic crystal fiber serves as both a scaffold for holding the electrodes (for electronic actuation) and an optical waveguide. Developing this capability is critical for probing the properties of nanoscale systems and devices at a single nano-object level.

Raman spectroscopy is pivotal for sensing and detection in applications in biomedicine, pollution sensing, and national security. It provides non-invasive, label-free chemical sensitivity by directly probing intrinsic molecular vibrational levels. However, its sensitivity is limited by the small molecular scattering cross section. Recently, micro-resonators have emerged as promising platforms to leverage the advantages of Raman spectroscopy for highly sensitive single particle detection. High-Q micro-resonators recycle pump power and create extremely long effective interaction length thereby enhancing the Raman signal. In this work, scattered Raman signal was collected from particles adhered to a micro-toroid resonantly pumped by a tunable laser and spectroscopic analysis was performed. Our results indicate the potential for strong enhancement of the Raman signal using a high-Q micro-toroid under optimum coupling conditions when the pump laser is locked on to the resonant mode of the toroid. Poster 56 _____________________________________________________________________ Optical Characterization of Unique Engineered Materials C. Janisch, D. Ma, N. Mehta, Z. Liu Abstract: New fabrication techniques have created fantastic, unique material structures for a diverse array of applications in optics and photonics, such as broadband polarizers, magnetic mirrors, optical parametric oscillators, and ultrafast pulse characterization. These materials are fabricated as physical structures, generating new properties not available in the original bulk material forms. However, as these material structures become more complex, measuring their optical properties becomes an arduous task. We present unique optical measurement techniques to characterize several of these new material structures, including two-dimensional materials and metamaterials.

Materials Day 2013

31

Due to their ultimate thinness, two-dimensional materials provide new optical properties not present in bulk materials. Fabricated monolayer transition metal dichalcogenide islands, such as MoS2 and WS2, generate extreme photoluminescence much stronger than in bulk or exfoliated forms. Being non-centrosymmetric, these monolayers also exhibit high optical nonlinearity. We developed a model for SH generation in 2D materials near the focus of an objective and used it to characterize the second-order nonlinear susceptibility by measuring the epi-collected signal. Through this process, the second order nonlinear susceptibility of monolayer WS2 was calculated be approximately 4460pm/V, which is over three orders of magnitude larger than most common nonlinear crystals (such as BaTiO3). To harness the wide phase matching bandwidth of atomically thin monolayer WS2, it was used as the nonlinear medium to characterize a dispersed sub-100fs ultrashort optical pulse using the conventional SHG-cFROG technique.

Metamaterials are artificially engineered materials which possess novel electromagnetic properties that don’t occur naturally. Instead of utilizing strictly material properties, these metamaterials combine unique materials and surface structures to engineer new devices. One critical component of this process is the understanding of the refractive index of the material; however, measuring refractive index in non-absorptive thin film material is difficult. We use spectral holography to obtain complex scattering coefficients (i.e. reflection and transmission coefficients), from which we can retrieve refractive index, given that spectral holography is capable of measuring amplitude and phase simultaneously. By using a supercontinuum laser we can utilize a single source to characterize the coefficients of the metamaterial over a broad bandwidth. We have successfully utilized spectral holography to measure scattering coefficients from multiple metamaterials, including Zero Index Material (ZIM) (with and without substrate), Dielectric Magnetic Mirror (DMM), and have even applied it to determine dispersion parameters in complex optical waveguides. Poster 57 _____________________________________________________________________ Epitaxial Growth and Characterization of Gate-tunable Topological Insulator/ Insulating Ferromagnet Heterostructures A. Richardella, A. Kandala, J. Lee, T. Flanagan, R. Fraleigh, N. Samarth, M. Liu, N. Ong, R. Cava, J. Heron, D. Schlom Abstract: Topological insulators (TI’s) are a novel class of materials that behave like regular insulators/semiconductors in their bulk, but are spin-polarized and graphene-like at the surface. This means that in an ideal TI current will only flow along the surface, and not through the interior. Introducing magnetism in these materials has been shown to create a gap in the graphene-like surface states. This property of TI’s can be used to realize transistor-like action by manipulating the magnetism of an adjacent magnetic layer. Such realizations would however require insulating magnetic materials in order to avoid any leakage currents, and to ensure charge flow solely through the TI. Using molecular beam epitaxy, we demonstrate the integration of candidate TI materials (such as Bi2Se3, Bi2Te3) with a number of rather rare, exotic insulating ferromagnets (GdN, GaMnAs, LuIG). This work was supported by DARPA (N66001-11-1-4110), ONR (N00014-12-1-0117) and the Pennsylvania State University Nanofabrication Lab (ECS-0335765).

Poster 58 _____________________________________________________________________ MEMS Piezoelectric Energy Harvesting C. Yeager, H. Yeo, S. Trolier-McKinstry

Abstract: The development of self-powered wireless microelectromechanical (MEMS) sensors depends on the ability to harvest energy from the environment. When solar energy is not available, mechanical energy from vibrations is particularly well suited. Piezoelectric thin films such as Pb(Zr,Ti)O3 (PZT) enable MEMS devices to convert mechanical to electrical energy, though increasing harvested power levels remains the main challenge for this technology to become ubiquitous.

This work shows that PZT thin films doped with Mn can have piezoelectric energy harvesting figures of merit (FoM= e31,f

2/εr) four to ten times greater than AlN when deposited on substrates with comparatively large thermal expansion coefficients, such as MgO, CaF2 and Ni. MEMS cantilevers with natural frequency below 100 Hz have been designed to demonstrate energy harvesting using such high FoM PZT films. The micromachining will be explained in depth, including the complete transfer of the PZT films from the original substrate onto a flexible parylene membrane. The shaker table setup used to characterize the piezoelectric MEMS cantilevers is described. It is shown that PZT thin film piezoelectric energy harvesters with footprints less than 1cm2 can generate over 8 µW of power at a sinusoidal acceleration of 0.3 g at 50 Hz. When extrapolated to a 1 g excitation, the predicted power output is over 88 µW. Poster 59 _____________________________________________________________________ Carbon Materials Synthesized from the Cold Compression of Aromatic Hydrocarbons and SWNTs T. Fitzgibbons, M. Guthrie, E. Xu, Y. Lin, W. Mao, V. Crespi, G. Cody, R. Hoffmann, J. Badding Abstract: Carbon has a unique capacity for catenation which leads to a variety of stable allotropes with drastically different materials properties. Depending on its local bonding environment carbon can exist as a soft, highly reflective metal, as in graphite or an ultrahard, transparent, insulator as in diamond. Carbon not only exists in the aforementioned 3-D bulk crystals graphite and diamond, but as 0-D fullerenes, 1-D nanotubes, 2-D graphene, and a wide array of amorphous phases that bridge the materials properties between that of graphite and diamond. Additionally, carbon readily bonds with heteroatoms such as oxygen, nitrogen, and hydrogen which add to the structural complexity and materials properties available. My work has focused on how pressure can control and alter the hybridization state and the subsequent structure of carbon materials. Many of the materials formed from the cold compression of

Materials Day 2013

32

small molecules and carbon nanomaterials are difficult to analyze due to their small size, low crystallinity, and low electron density. I will present three systems that I have studied: the amorphization of acene molecules, the formation of graphitic polyhedra from SWNTs, and the synthesis of a new sp3 bound C-H nanotube.

The characterization of amorphous hydrogenated carbon films has been an area of active research for many years. I have used multiwavelength Raman spectroscopy along with FT-IR and transmission electron microscopy to determine the microstructure of amorphous carbons formed from the high pressure polymerization of n-acenes (n = 2,3, and 5). In addition to their microstructure, information was gathered on the solid state reactivity of these acenes. It was determined that naphthalene polymerized at the highest pressure into a polymer-like amorphous hydrogenated carbon whereas the longer acenes, anthracene and pentacene, polymerize into highly hydrogenated graphite-like amorphous hydrogenated carbons. Due to their potential industrial applications, it is important to be able to characterize these complex systems in order to easily tie together structure property relations and intelligently design future carbon-based materials. Poster 60 _____________________________________________________________________ XPS and AES: Important Characterization Tools for the Physical, Engineering, and Life Sciences V. Bojan Abstract: Surface and interfacial chemistry and structure play important roles in a variety of materials systems of great interest in the physical, engineering, and life sciences. X-Ray Photoelectron Spectroscopy (XPS or ESCA) and Auger Electron Spectroscopy (AES) are characterization techniques that can provide surface sensitive, spatially resolved elemental and chemical state information about a wide variety of materials systems. Both techniques are available at the Penn State Materials Characterization Lab. The usefulness of XPS and AES in the physical, engineering, and life sciences will be illustrated with a series of examples. Poster 61 _____________________________________________________________________ Materials Characterization: Using Solid-State NMR to Understand the Formation and Role of Surface Alteration Layers on Nuclear Waste Glass K. Murphy, N. Washton, J. Ryan, C. Pantano, K. Mueller Abstract: Despite the expected participation of alteration layers in the temporal decrease of ion exchange and corrosion rate of nuclear waste glass, the mechanism of formation is unclear. In order to differentiate between the functions of species retained in the glass versus those released to solution, constituents were labeled with distinct isotopes of Si and B. Glass powders were corroded for fixed time periods at 90 °C with a S/V ratio of 100,000 m-1. Subsequently, the supernatants for the distinct isotope-containing glasses were switched and corrosion continued. The structural role of glass components during the formation of the alteration layers was monitored by solid-state nuclear magnetic resonance (NMR). 29Si magic angle spinning (MAS) NMR spectra indicated an increase in Q3 and Q4 silicon species with exposure time, suggesting recondensation of silicon from solution onto the glass powder. The extent and rate of recondensation was a function of the glass composition and total corrosion time. The dynamic interaction between the solution and glass powder was further validated by the behavior of aqueous boron as observed by 11B MAS NMR. Cross-polarization (CP) MAS NMR techniques isolated the structure of alteration layers in order to highlight differences from the bulk glass. Poster 62 _____________________________________________________________________ Enhancing Signal-to-noise Ratio in Zero-mode Waveguide-based Single-molecule Fluorescence Studies by Dark Field Illumination D. Chen, Y. Zhao, H. Yue, C. Zhao, T. Huang, S. Benkovic Abstract: Zero-mode waveguides (ZMWs), the cylindrical nanoaperture array in metal clad, are particularly attractive nanostructures for single-molecule fluorescence studies. With the subwavelength dimensions, ZMWs confine incident illumination beam to yield the observation volume of ~10-21 L, a value of 3 orders of magnitude smaller than that of diffraction-limited microscopies. This feature enables single-molecule fluorescence assay at the physiologically relevant concentrations of fluorescent biomolecules. Despite this advantage offered by ZMWs, implementation of ZMWs to single-molecule biological inquires has been hampered by varied technical difficulties, including fabrication, surface passivation and fluorescence microscopy for ZMW array. While most of the efforts have gone into simplification of ZMW fabrication and development of ZMW surface passivation methods, optimization of fluorescence microscopy for ZMW has gravely lagged behind. In this study, we evaluated the background, noise, and signal-to-noise (S/N) levels in ZMW-based single-molecule fluorescence experiments using epi-fluorescence microscopy configuration. We found that the conventional epi-fluorescence for illuminating ZMW array suffered from high background and noise levels caused by leakage of excitation beam to detection unit. To address this issue, we developed a modified dark field configuration for illumination of ZMW array, in which excitation and emission light paths are spatially orthogonal. We showed that ZMW-based single-molecule fluorescence experiments using dark field illumination displayed substantially lowered background and noise levels with the average S/N improved from 1.78 (epi illumination) to 4.93, facilitating single-molecule FRET studies in ZMW array at the micromolar concentrations

Materials Day 2013

33

Poster 63 _____________________________________________________________________ Mechanism of Enhanced Carbon Cathode Performance by Nitrogen Doping in Lithium-sulfur Battery – an X-ray Absorption Spectroscopic Study P. Zhu, J. Song, D. Lv, D. Wang, Y. Chen Abstract: Lithium-sulfur batteries have drawn much attention in advanced energy storage due to its high theoretical specific capacity. However, the most severe problem is the rapid capacity loss due to dissolution of polysulfide into electrolyte during charge/discharge cycles. Nitrogen-doped mesoporous carbon cathode materials were found to effectively immobilize sulfur species and minimize the sulfur loss during charge/discharge processes. To understand the mechanism of nitrogen promotion effect in mesoporous carbon, X-ray absorption near edge structure (XANES) spectroscopy was employed to probe the chemical environments of N, C, O, and S. It is concluded that other than providing additional adsorption sites the nitrogen dopants make the oxygen functional groups on the carbon surface more reactive and bond more readily with sulfur. The finding will help the lithium battery researchers to more effectively develop carbon cathode materials. Poster 64 _____________________________________________________________________ Focused Ion Beam/Scanning Electron Microscopy (FIB/SEM): Why Every SEM User Should Know about This T. Clark, Materials Characterization Lab Abstract: If you have used a scanning electron microscope (SEM) and haven’t heard of the focused ion beam (FIB), you should stop by.

With the FIB, you can: o modify your specimen to make fast cross sections of the subsurface o prepare site-specific TEM specimens o determine the 3D structure of your sample o physically manipulate and mechanically test particles o deposit electrical contacts and o mill complex patterns via ion lithography

If any of these sounds useful and you would like to discuss your application, please stop by.

Poster 65 _____________________________________________________________________ Scanning Electron Microscopy (SEM): Imaging Tough Samples with High Contrast and High Resolution T. Clark, Materials Characterization Lab Abstract:

o Do you have a sample that is difficult to image, but you cannot coat it? o Are you trying to image a crystalline sample and need more contrast? o Do you need high spatial resolution elemental maps?

We routinely perform such analyses via SEM. Please stop by to see examples. Poster 66 _____________________________________________________________________ A Detailed TEM Study of Carbon Nano-onions Structure C. Gaddam, R. Vander Wal Abstract: Graphitized carbon nano-onions (CNOs) were synthesized through high temperature annealing over extended times in batch processes. Bright and dark field transmission electron microscopy (TEM) and selected area electron diffraction (SAED) is performed and discussed. The potential for these techniques to characterize the degree of graphitization, as manifested by crystallite growth is discussed and applied to the CNOs. High-resolution bright field TEM reveals a greater level of material organization by the number of parallel layer planes forming the particle outer wall. Increased diffraction intensity in dark-field TEM reflects the higher crystallinity of the CNOs. Combined with EELS, these techniques provide a comprehensive measure of the degree of graphitization. Poster 67 _____________________________________________________________________ Transmission Electron Microscopy: Structural and Chemical Characterization from the Micron Down to the Atomic Scale J. Gray, T. Clark, J. Maier, K. Wang Abstract: The transmission electron microscopes (TEM) in Penn State’s Materials Characterization Lab (MCL) enable one to determine the microstructure, atomic structure, chemical composition, and chemical bonding in a thin sample. There are currently four microscopes that provide a full range of capabilities and techniques, including imaging, diffraction, energy dispersive spectroscopy (EDS), electron energy loss spectroscopy (EELS), and in-situ analysis during heating/cooling/straining. The newly installed FEI Titan3

Materials Day 2013

34

aberration corrected TEM is one of the most powerful microscopes in the world, with the ability to do atomic scale spectroscopy and imaging at a resolution of less than one Angstrom. The addition of two aberration correctors to the lens system, as well as a monochromator, provides resolution enhancement for a range of accelerating voltages including a maximum of 300 kV down to 60 kV. New techniques, including tomography and magnetic imaging, will also be available with this instrument in addition to fast EDS mapping over large sample areas. These capabilities can provide a wealth of information for a wide range of materials such as nanoparticles and nanowires, thin films, organic materials, bulk materials and composites, device structures, catalysts, etc. Poster 68 _____________________________________________________________________ Sub-Angstrom Structural Distortions in an Atomically Thin Hexagonal Boron Nitride Membrane N. Alem Abstract: Defects can modulate the electronic properties of crystals by introducing empty states within their band gap. When exposed to chemical functional groups, defects can trap molecules and adatoms and significantly change the electronic and sensing properties of the crystal. Atomically thin two dimensional crystals, such as graphene and hexagonal boron nitride (h-BN) are considered emerging materials with variety of applications in sensing, hydrogen storage, and electronics. Structural relaxations at the defects and edges in these crystals can have a significant impact on their resulting physical, chemical and electronic properties. This work presents the relaxation effects at the edges and vacancies at the sub-Angstrom size scales and its effect on the physical and electronic properties of h-BN. In this study, we use ultra-high resolution aberration-corrected electron microscopy to probe the underlying physics at the atomic scale in a bilayer of h-BN. Our experimental investigations coupled with first-principles calculations uncover formation of interlayer bonds across the bilayer h-BN membrane at the boron monovacancies and at the zigzag edges. This structural distortion alters the scattering potential, leading to a significant phase shift around the boron monovacancies and edges. Such a phase shift leads to the chemical identification of boron monovacancies as opposed to nitrogen defects. Poster 69 _____________________________________________________________________ The High Field MRI Facility at Penn State T. Neuberger Abstract: The High Field Magnetic Resonance Imaging (MRI) Facility at the Pennsylvania State University houses two Agilent preclinical MRI systems operating at field strengths of 7 and 14 tesla. In addition, we have access to a 3 tesla Siemens clinical system housed in the 3 Tesla MRI Facility, as well as to a 20 tesla Bruker ultra high field system housed in the NMR Facility of the Department of Chemistry. Although MRI is usually known for its non-invasive character and its excellent soft tissue contrast in in vivo experiments, it can be applied in many other research areas. MRI is for example capable of measuring diffusion or temperature changes in certain experimental setups. It can be used e.g. to look at moisture distribution in drying concrete or quantitative lipid allocations in seeds. Research areas of the material sciences community the High Field MRI Facility is engaged in right now are e.g. the development of new multimodal contrast agents and the development of new concepts and designs, as well as the construction and testing of new magnetic resonance radio frequency detectors. Poster 70 _____________________________________________________________________ Scanning Probe Microscopy within the Materials Characterization Lab T. Tighe Abstract: Scanning probe microscopy (SPM) is an umbrella term for the branch of microscopy that provides spatially localized information by raster scanning a sharp probe and a surface in close proximity to each other and monitoring probe-sample interactions. A variety of surface properties can be measured in addition to topographic information, such as electrical, magnetic, and nanomechanical data depending on the type of interactions investigated. SPM has a vast number of applications in many areas of science and technology: chemistry, physics, materials, biology, engineering, etc. Poster 71 _____________________________________________________________________ Connecting with the Materials Characterization Lab MCL Staff Abstract: Join us on twitter @PennStateMCL or visit our website at http://www.mri.psu.edu/facilities/mcl/ Poster 72 _____________________________________________________________________ Characterization and Structure Analysis of Faujasites from a Jordanian Volcanic Ash D. Vaughan, H. Yennawar, Anthony J. Perrotta+ Abstract: Synthetic faujasite (FAU) is the most important industrial synthetic mineral, made in many thousands of tons for use as petroleum catalysts used to convert crude oils to fuels and lubricants. In nature it is rare, found only in about a dozen volcanic localities in basaltic lava vugs. Volcanic ash derived zeolites have important uses but these comprise mainly mordenite, phillipsite,

Materials Day 2013

35

chabazite, and clinoptilolite. FAU is a rarity in such deposits but has recently been found in a Jordanian ash. Density separation of s grab-sample yielded a FAU concentrate, and the ground sodium exchanged material analysed as typical FAU (Si/Al~2; space group Fd3m; Unit Cell~24.7Ǻ). From the matrix two single crystals were selected and evaluated by X-ray diffraction. Surprisingly, resolved to a minimum R value, both samples yielded non-Fd3m space groups even though topologically both were clearly FAU, presumably distorted by cation contents and locations. One resolved to a triclinic the second to an orthorhombic space group. Poster 73 _____________________________________________________________________ MCL Electrical Characterization Lab M. Lanagan, J. Long, S. Perini, R. Wilke Abstract: The laboratory is dedicated to the electrical characterization of materials. Measurements can be performed on both thin film and bulk samples over a wide range of conditions. Facilities exist to measure samples from -190 C to 750 C, with applied voltages up to 30 kV, and over frequency ranges of 1 mHz to 26 GHz. Using a custom built data acquisition system (GADD), fully automated measurements can be performed across a wide variety of platforms. GADD allows for the acquisition of multidimensional data sets, with the user only needing to specify the measurement parameters.

Common types of measurements include AC Complex Impedance, AC/DC breakdown, DC current/resistance, polarization vs. electric field (with strain), highly accelerated lifetime testing (HALT), deep level trap spectroscopy (DLTS), and van der Pauw resistivity. Poster 74 _____________________________________________________________________ Materials Characterization – X-ray Scattering Techniques N. Wonderling Abstract: X-ray scattering techniques utilize the various means of interaction between a material and an x-ray beam – the beam is scattered, transmitted, or absorbed – to characterize a wide variety of materials. The elastically scattered portion of the beam produced by interaction with the material’s electrons provides valuable information about the nature of the material. Detection of that scattered beam as a function of direction yields information about electron density distribution. In crystalline materials, (materials that have long range order of electron distribution), the electron density distribution creates strong scattering in discrete directions. The scattering direction, combined with intensity information, provides information about the structure of the material in what is typically know as an x-ray diffraction experiment.

X-ray diffraction is the most broadly used form of x-ray scattering characterization, but there is a wealth of information that can be obtained from x-ray sources that goes far beyond diffraction, including small angle scattering and x-ray reflection techniques.

A variety of equipment is available through the Materials Characterization Laboratory to harness the power of x-ray scattering. Please stop by during the poster session and talk to our staff about the variety of information x-ray scattering can bring to your research. Poster 75 _____________________________________________________________________ Multiscale Stress-strain Characterization of Outer Onion Epidermal Peel Tissue K. Kim, A. Haque, S. Zamil, H. Yi, V. Puri Abstract: The growth of primary cells is thought to be regulated by modifying mechanical properties of cell wall. Mechanical characterization of primary cell wall at the micrometer size is non-trivial and often only macro-scale measurement is feasible. In this study, we developed an experimental technique that enables multiscale, from tissue level to cell level, strain measurement of outer onion epidermal peels under externally applied and controlled mechanical force. The technique thus provides us with the global (or far-field) and local mechanical properties at the same time. Towards that end, the outer onion epidermal tissues were cut and bonded using epoxy glue on MEMS-based displacement-controlled loading devices to apply and measure the force on the specimen. Fluorescent polystyrene beads of 500 nm diameter were dispersed on the surface of onion epidermal peel layer. Uniaxial tensile experiment was performed under a confocal fluorescent microscope and images of epidermal tissues under each tensile load were obtained. The resulting strain is independently measured using a digital image correlation (DIC) technique by tracking individual bead displacements along and across the loading (orthogonal). Applied forces were obtained by measuring the deformation of MEMS device. The far-field and local mechanical properties were quantified by calculating applied stress and corresponding global and local strain. Mechanical property values of individual cells (Young’s modulus: 1.9 GPa) resulted in different values from those of the global tissue-scale (Young’s modulus: 3.0 GPa). Results on global, cell-to-cell, and point-to-point mechanical property variations suggest that multiscale investigation is essential for fundamental insights in the hierarchical deformation in biological systems.

Materials Day 2013

36

Poster 76 _____________________________________________________________________ Characterization of a Corrosion Resistant Coating for Steel and Glass J. Mattzela, C. Pantano Abstract: Protective corrosion resistant coatings have garnered a lot of interest, especially with the cost of corrosion estimated to approach over $500 billion in 2013 within the United States alone. Corrosion resistant coatings are deposited by a number of techniques, including chemical vapor deposition (CVD). CVD coatings offer several distinct advantages such as improved interface adhesion and conformal three-dimensional surface coverage. The current work characterizes a commercially available CVD-deposited corrosion and wear resistant coating. This coating is comprised primarily of silicon, oxygen, and carbon constituents and is characterized using standard surface characterization techniques such as X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy. Poster 77 _____________________________________________________________________ Using Traditional Surface Characterization Techniques in Novel Ways: from Developing Lubrication in MEMS to Elucidating Cellulose Crystal Structure for Biofuels A. Barthel, C. Lee, A. Al-Azizi, K. Kafle, N. Surdyka, S. Kim Abstract: Concerns over the scarcity of energy are becoming increasingly important in the world’s economy. There are two innovations needed for a stable energy market: the development of new energy sources, and the reduction of energy consumption. Our group investigates aspects from both of these goals by applying surface characterization techniques to explore these problems in new ways. We study friction from the macro- to nano-scale for applications such as low power micro-electromechanical systems (MEMS), and also probe the crystal structure of cellulose so that it can be efficiently used as a renewable source for fuels and chemicals. We have shown various lubrication techniques – including one-time coatings such as diamond-like carbon (DLC), self-assembled monolayers (SAM), and ionic polymers, surface texturing by creation of nanoscopic wells, and the adsorption of lubricating molecules from the vapor phase – to be beneficial in prolonging the lifetime of sliding contacts from the macro- to the nano-scale. We then characterize the chemical reactions occurring at sliding contacts under these conditions using techniques such as Atomic Force Microscopy (AFM), X-ray Photoelectron Spectroscopy (XPS), and Attenuated Total Reflection Fourier-Transform Infrared Spectroscopy (ATR-FTIR). On the biological front, the structure of lignocellulosic biomass has been challenging to understand, due to the chemical complexity found in nature and lack of suitable analytical techniques. For the first time, Sum-Frequency Generation (SFG) vibrational spectroscopy is being used to analyze the crystalline structure of cellulose in plant cell walls. Understanding the nano-scale structure of cellulose in vivo is critical to engineering efficient pathways to biofuels. By applying these characterization techniques, we aim to discover new details about the nano-scale behavior of important mechanical and biological systems. Poster 78 _____________________________________________________________________ Biomass Conversion: Converting Sugars into Fuels and Chemical Building Blocks for Plastics W. Yang, F. Pong, A. Sen Abstract: According to the U.S. Energy Information Administration, by 2011 the world was consuming a staggering 88,000,000 barrels of oil each day. This number only continues to grow as energy demands increase annually, particularly in countries - such as China - which are in a period of rapid economic development. Petroleum is a finite source and, additionally, the process of oil drilling and the use of oil has had and continues to have adverse effects on the environment. As such, researchers in both industry and academia have become increasingly invested in finding alternative fuel sources that can (1) help alleviate growing worldwide need for energy/oil-based products and (2) can be harvested through more environmentally friendly methods. One popular choice is to synthesize fuels from biomass, a renewable resource which is comprised of cellulosic materials (i.e. wood, corn husks). Cellulose can be broken down into sugars and subsequently used to synthesize alternative fuels and chemical building blocks (olefinic monomers) for plastics.

A previous group member, Dr. Weiran Yang, developed a biphasic system capable of synthesizing 2,5-dimethyltetrahydrofuran (DMTHF), a gasoline substitute, from fructose, a cellulosic sugar in high yields (up to 81%). This biphasic system was composed of a metal catalyst, hydriodic acid, an extracting solvent, and hydrogen gas. Dr. Yang also discovered that it is possible to use this system to convert polyols – linear-chain sugars ranging from 3 to 6 carbons in length – into a wide range of synthetically pure iodoalkanes. Iodoalkanes can then be easily reduced to olefins, the building blocks of polyethylene (PE), which is the most widely used plastic in the world.

I have continued studying this biphasic system in regards to iodoalkane synthesis, and have focused on changing reaction conditions (i.e. changing catalyst type, reactant amounts) both optimize to product yields and to extend the lifetime of the catalyst system. In my poster, I will briefly summarize the scientific contributions our group has made towards biomass conversion. A majority of my presentation will be focused on the iodoalkane synthesis, which includes effects of changing reactant conditions, the problems encountered in chemically improving the system, and possible solutions for these problems.

Materials Day 2013

37

Poster 79 _____________________________________________________________________ AnInsolubleStarch‐basedFoamProducedthroughMicrowaveExpansionY.Deng,J.CatchmarkAbstract: An insoluble biocomposite composed of potato starch and chitosan was prepared by microwave treatment. The effect of pH on swelling (liquid absorption) behavior of the composites was investigated at pH 2, pH 6.8 and pH 12. Analysis revealed that the swelling ratio of composites depends both on the aqueous pH value and the content of the chitosan. Composites exhibited a relatively high swelling ratio at pH environment lower than the pKa of chitosan (about 6.3). Glucose analysis by ion exchange chromatography showed that there was little hydrolysis of such composite at low pH. When immersed in the same pH solution, a composite with higher chitosan content had higher swelling ratio. The microstructure of composites produced was also investigated by FE-SEM. Poster 80 _____________________________________________________________________ Conventional- and Microwave-hydrothermal Synthesis of BiVO4 M. Sarkarat, S Komarneni Abstract: Monoclinic bismuth vanadate BiVO4 was successfully prepared through a facile and rapid microwave-hydrothermal process using Bi(NO3)3 and NH4VO3 as starting chemicals in the temperature range of 100-150°C and treatment time range of 5-60 min. The BiVO4 powders with various morphologies and sizes were synthesized by adjusting the pH. The microwave-hydrothermally synthesized BiVO4 powders were investigated by X-ray diffraction for determining phase purity and scanning electron microscopy (SEM) for characterizing morphology and particle size. It was found that pH and the reaction time had a considerable effect on morphology, size and crystalline structure of the product. The photocatalytic activities of the BiVO4 powders were also evaluated for decomposition of NOx. Poster 81 _____________________________________________________________________ Polymer Derived Carbons for Energy Related Applications R. Rajagopalan Abstract: Porous carbon materials derived from pyrolysis of thermosetting resins such as polyfurfuryl alcohol can be used in various applications that include electrodes in energy storage devices like electrochemical capacitors and batteries, catalyst supports, gas adsorbents and gas separation membranes. Porosity at different length scales ranging from microporosity (< 2 nm), mesoporosity (2 – 50 nm) and macroporosity (> 50 nm) can be designed in these materials by proper choice of polymer precursors and use of physical activation processes such as CO2 or steam activation. In addition to the control of pore size, other properties such as chemical purity, microstructural properties and surface functionalization can also be tailored, making them attractive for several applications. The poster will provide an overview of porous carbon synthesis, their characterization, and highlight the role played by these materials in various applications. Poster 82 _____________________________________________________________________ Sequestration, Retention, and Release of Solutes Using Aptamer-functionalized Polymeric Materials M. Battig, S. Li, Y. Wang Abstract: Materials for applications in fields such as industrial catalysis, separation, and regenerative medicine are requiring more sophisticated molecular recognition properties to regulate processes with stricter control. By using nucleic acid aptamers to functionalize polymeric materials, we can create innovative materials to meet such a demand. For example, superporous materials can be functionalized with aptamers to enhance solute retention. The porous architectures of superporous materials allow for the rapid influx or efflux of solutes. However, the porous structure becomes a challenging issue when the retention of solutes is desired. To create superporous materials capable of quickly absorbing solutes but retaining them within the material, the material was functionalized with nucleic acid aptamers. By incorporating aptamers into a superporous material, we were able to sequester solutes from solution and retain nearly 100% of the solutes within the material over a period of two weeks. Moreover, the solutes could be released out downstream when needed. Thus, aptamer-functionalized materials are a promising platform for the development of advanced materials. Poster 83 _____________________________________________________________________ Stimuli-responsive Plastics that Respond to Trace Signals via Depolymerization M. Olah, A. DiLauro, S. Phillips Abstract: This poster presents our current research on plastics that respond selectively to trace signals to perform a specific action. In the presence of the signal, the plastics respond by disassembling continuously and completely to the constituent monomers, i.e., through depolymerization. We have designed three distinct classes of depolymerizable polymers that possess this capability: poly(benzyl ethers), poly(carbamates), and poly(phthalaldehydes). These polymers are stable under ambient conditions, but depolymerize rapidly, some in seconds, only in the presence of specific stimuli. This poster describes methods for synthesizing the

Materials Day 2013

38

polymers, characterization of their abilities to depolymerize selectively, strategies for increasing the rate of depolymerization, and applications of these polymers. These polymers are being developed for emerging technologies such as nanolithography, diagnostics, controlled release, recyclable plastics, and biomedical materials. Poster 84 _____________________________________________________________________ MOCVD Growth of Group III-Nitrides J. Gagnon, Z. Al Balushi, S. Eichfeld, H. Shen, Y. Yuwen, T. Mayer, J. Redwing

Abstract: The direct bandgaps of III-nitride compound semiconductors—namely AlN, InN, and GaN—span the entire visible spectrum from infrared to ultraviolet energies. Furthermore, ternary compounds of the III-nitrides can be formed which allows for bandgap tuning within this range based on alloy composition. Due to this, combined with the high electron mobility and breakdown field of GaN, there is an interest in using III-nitride materials for light emitting applications and high power device structures. Unfortunately, the III-nitrides suffer from lattice mismatch between the binary compounds. Furthermore, the III-nitrides lack inexpensive bulk substrates for homoepitaxial growth, which results in the use of heteroepitaxial substrates such as Si, SiC, and sapphire. These substrates can lead to detrimental lattice and thermal stresses in heteroepitaxially grown films which can result in the formation of threading dislocations and surface cracks in III-nitride film and device structures. Our group research is focused on in situ and ex situ characterization of stresses in III-nitride films as well as the effects that growth conditions and substrate modification have on these stresses.

Our current research studies focus on N-polar growth of InGaN and non-polar growth of GaN on structured Si substrates. Films are grown via metalorganic chemical vapor deposition in a reactor that is equipped with an in situ laser reflectance system that can track the wafer curvature during the entire growth process. The film stress evolution during growth can be calculated from the in situ curvature data. N-polar growth of InGaN is a promising technique for films with high In fractions which is essential for tuning the bandgap to the required emission wavelengths for green LEDs. Poster 85 _____________________________________________________________________ Process-structure-property Relationships of Thick Gd2O3 Films for Neutron Detection D. Grave, D. Wolfe Abstract: Due to gadolinium’s excellent neutron capture cross section, Gd-containing materials have emerged as leading candidates in solid state neutron detection. Micron-thick Gd2O3 films were deposited by reactive electron beam physical vapor deposition (EB-PVD) for use in novel radiation detectors. Incorporation of the Gd2O3 films into both conventional silicon based electronics and aluminum gallium nitride (AlGaN) / gallium nitride (GaN) high electron mobility transistors (HEMTs) has been studied. The effects of film processing on the structural, optical, and electrical properties of the Gd2O3 films will be presented and related to device performance. Poster 86 _____________________________________________________________________ Oxides Thin Films for Infrared Imaging Prepared by Biased Target Ion Beam Deposition Y. Jin, T. Jackson, M. Horn Abstract: Modern thermal imaging cameras employ focal plane arrays based on resistive microbolometer pixels. The microbolometer pixel is the thermal detector with sensing material which changes its resistivity by absorbing incident infrared radiation (IR). As one of the main sensing materials, commercial grade nanocomposite vanadium oxide thin films, are exclusively prepared by ion beam deposition (IBD) in the resistivity range of 0.01-1 ohm-cm and temperature coefficient of resistivity (TCR) of -2%/K to -3%/K. Our group has studied pulsed-dc magnetron sputtered VOx thin films with comparable bolometric properties to IBD prepared VOx. In this study, a new biased target ion beam deposition (BTIBD) system has been used to prepare microbolometer sensing materials. This system is based on novel technology which incorporates the advantages of ion beam deposition and conventional sputtering. In BTIBD system, low energy ions (<25eV) are remotely generated and the targets are negatively biased independently for sputtering. A residual gas analyzer (RGA) can be utilized to control the reactive gas partial pressure during reactive sputtering. Molybdenum oxides and nickel oxides thin films have been prepared by BTIBD system and show comparable bolometric properties to the commercial grade VOx currently used in microbolometers. However, the deposition rates of MoOx and NiOx are much higher and processing control is easier than for VOx, which could mean a higher throughput and lower cost for industrial fabrication. In addition, high TCR (>-4.5%/K) VOx thin films with resistivity in the range of 1E3 to 1E4 ohm-cm are also prepared by BTIBD system. The high TCR and high resistivity VOx thin films are potential sensing materials for next generation uncooled IR focal plane arrays with a through-film structure. This structure potentially improves the sensitivity of the bolometer pixel without increasing Johnson noise, thus improving the thermal camera resolution.

Materials Day 2013

39

Poster 87 _____________________________________________________________________ Horn Thin Film Group M. Horn, Y. Jin, H. Basantani, H. Lee, R. Banai, F. Aronovich, N. Tanen, M. Nunez, R. Gresh, A. Narccarelli Abstract: The Horn thin film group focuses on the fabrication and application of novel engineered thin films. Different projects are shown in this poster, including: SnS thin films for solar cell; vanadium oxides, nickel oxides and molybdenum oxides thin films as imaging layer for uncooled microbolometer; NiTi thin films for memory shape alloy; and Mg/Ti/Al PVD films for batteries and bioadsorbable materials. A biased target ion beam deposition based on new technology combines ion beam deposition and conventional sputtering has been used to prepare these thin films. The low ion beam is remotely generated by ion gun and up to three 4” targets can be independently biased for sputtering. The sputtered species can be precisely controlled by controlling the ion source energy and current as well as power, pulse frequency on different targets, and reactive gas partial pressure by RGA. Due to the low energy of Ar ions (<25 eV) generated by ion source, the vacuum system materials will not be sputtered during the deposition, which allows the deposited films to be very contamination-free compared to deposited thin films prepared by other techniques. A Woollam RC2 ellipsometer installed on the BTIBD system is used to monitor and measure the real-time in-situ deposition as well as post-deposition treatment of deposited films. Poster 88 _____________________________________________________________________ Investigation of the Use of a Laser-sustained Plasma (LSP) in Titanium Nitriding A. Kamat, J. Todd Abstract: The Center for Multiscale Wave-Materials Interactions studies laser-assisted material processing, especially the formation of protective coatings on metal surfaces. Methods for striking a free-standing, laser-sustained plasma (LSP) in an open air atmosphere, using nitrogen, argon or varying gas mixtures, were established. The nitrogen plasma was characterized using optical spectroscopy, and the temperature measurements agreed well with the predictions of a CFD model created using FLUENT. Interaction of the nitrogen LSP with metals such as titanium/zirconium/hafnium produced wear-resistant, nitride, surface coatings. With the laser beam and LSP oriented perpendicular to a titanium substrate, processing conditions resulting in the formation of crack-free nitride trails were identified. When the laser beam and LSP were oriented parallel to a titanium substrate, very rapid growth of TiN could be achieved – e.g. ~100 µm in 5 seconds. Current research is (a) exploring processing conditions that will produce wide-area, crack-free coatings during surface coverage by overlapping multiple trails; (b) further characterizing the plasma; and (c) manipulating the plasma shape and size using a magnetic field to determine potential effects on the quality of TiN coatings. Energy transfer from the plasma to the substrate is being investigated by recording temperature measurements at the rear surface of the substrate. Solutions to the inverse heat conduction problem are then obtained to determine the heat flux from the plasma to the substrate. The overall goals of this work are to develop reliable methods for forming functionally graded TiN coatings in an open air atmosphere using a nitrogen LSP. Poster 89 _____________________________________________________________________ The Center for Innovative Material Processing through Direct Digital Deposition F. Lia, R. Martukanitz Abstract: The Center for Innovative Material Processing through Direct Digital Deposition (CIMP-3D) is a University-wide initiative to focus and coordinate the vast technical resources within Penn State towards the advancement and deployment of additive manufacturing (AM) technology for the benefit of the national industrial base. This mission, which is supported through various federal and private sector sponsorship, is being fulfilled through three primary objectives:

• Advancement and integration of enabling technologies required to exploit AM process attributes during design and optimize AM processing conditions for producing qualified components and structures.

• Collaboration with industry in the development and transfer of AM technologies through process selection, demonstration and validation as a “trusted broker”.

• Promotion of AM technologies through training, education, and dissemination of information. Poster 90 _____________________________________________________________________ Multidisciplinary Research for Additive Manufacturing at CIMP-3D F. Lia, R. Martukanitz Abstract: CIMP-3D is a multidisciplinary research association which draws upon the unique talents, expertise, and emphasis of various organizations:

Major research activities within Penn State Primary research partners Industry and government associates.

The broad range of disciplines that are captured by the Faculty Associates of the Center are illustrated.

Materials Day 2013

40

Poster 91 _____________________________________________________________________ Surface Reactivity of Hydroxyl Groups on Aluminum Oxide Powders Probed with Chlorotrimethylsilane B. Ludwig, J. Stapleton, C. Pantano Abstract: Research on the subject of oxide surface chemistry has been ongoing for many years. Metal oxides specifically are naturally abundant, resulting in their widespread use in many different industries, from hydrocarbon oxidation to semiconductors. Chemical surface modification of these oxides also opens a new realm of uses for the materials. We have studied the surface modification of pure aluminum oxides and with a common surface treatment agent, chlorosilane. This study investigates the nature of the reactivity of hydroxyl sites found on each of the aluminum oxides studied with chlorotrimethylsilane (CTMS), a hydrophobic surface modification reagent. Two major, structurally different, phases of aluminum oxide (alpha and gamma), as well as boehmite were all subjected to thermal pre-treatment to create reproducible surfaces prior to gas phase CTMS exposure. The resulting surfaces were investigated using diffuse reflectance infrared spectroscopy (DRIFTS) and X-ray photoelectron spectroscopy (XPS). In situ DRIFTS was used to monitor the gas phase reactions and identify the types and follow the reactivity of surface hydroxyls. Poster 92 _____________________________________________________________________ Battery and Energy Storage Technology (BEST) Center Co-Directors: C. Rahn, C-Y. Wang Abstract: Penn State is leading the emerging research field of energy storage with the Battery and Energy Storage Technology (BEST) Center. The BEST Center was formed in 2011 to bring together the campus-wide expertise in energy storage, foster collaboration, and provide a focal point for research and education activities. The expertise of Penn State researchers within the BEST Center spans from materials to cells to systems. These BEST researchers have made and continue to make significant and pioneering contributions to the most important aspects of energy storage technology. The BEST Center co-directors, Chris Rahn and Chao-Yang Wang, invite you to visit our website (www.best.psu.edu) and engage our world-class researchers with your most challenging research and education initiatives in energy storage. Poster 93 _____________________________________________________________________ Advanced Thermal Barrier Coating Concepts Utilizing Unique Design Architectures M. Schmitt, D. Wolfe Abstract: Modern gas turbine engines used in power generation and aerospace operate at temperatures which exceed the capability of the most advanced metallic alloys and components. Therefore, these components must be protected from the high temperature combustion environment by means of a thermal barrier coating or TBC. State-of-the-art TBCs are composed of 7 wt% yttria stabilized zirconia (7YSZ) and are deposited via electron beam physical vapor deposition. These coatings are unstable beyond 1200 ºC and so new materials and coatings designs must be explored for next generation coatings. This work explored the use of two new classes of TBC materials; rare earth modified ‘Low-k’ YSZ and gadolinium zirconate. Layered architectures were also explored as a means to further modify the thermal and mechanical properties of the TBC system. Compared to 7YSZ, thermal conductivity has been reduced by 25% while sintering rates have dropped by almost 90%. This approach was also able to reduce the erosion rate with respect to gadolinium zirconate by 65% while maintaining a thermal conductivity significantly lower than 7YSZ. Poster 94 _____________________________________________________________________ Conditioning of Composite Lubricant Powder for Cold Spray M. Neshastehriz, I. Smid, A. Segall, T. Eden Abstract: Nano-engineered self-lubricating particles, comprised of hexagonal-boron-nitride powder (hBN) encapsulated in nickel, have been developed for cold-spray coating of aluminum components. The Ni encapsulant of the hBN (lubricant) consists of several nano-layers, which has been electroless-plated in aqueous solution in multiple steps, typically depositing 200-300 nm per step. Once the composite particles were created, they were cold sprayed onto aluminum substrates and evaluated for bond strength, friction, and reciprocation wear resistance. While the hBN lubricant improved friction and wear as expected, it appears that the improved bond strength is related to the potential hardenability of the encapsulant through plastic deformation. De-agglomeration and mechanical alloying of the particles has been performed by low- and high-energy ball milling. The un-milled and milled particles were characterized with SEM, EDX, XRD, BET, hardness as well as image analysis, before and after cold-spray deposition. Poster 95 _____________________________________________________________________ Drag Reduction of Slippery Liquid-infused Porous Surfaces N. Sun, T. Wong Abstract: Superhydrophobic surfaces are known to reduce skin drag against high surface tension fluids, such as water. However, when encountering low surface tension fluids, these surfaces fail to reduce skin drag and would often lead to drag enhancement. To resolve this issue, we have recently developed slippery liquid infused porous surface (SLIPS), which is composed of a chemically

Materials Day 2013

41

functionalized textured surface infused by a lubricating fluid. Measured through a cone-and-plate rheometer system, we found that SLIPS can reduce friction drag (up to 10%) for a variety of fluids, especially low surface tension alkane hydrocarbons, such as hexadecane, dodecane and undecane, the main components of crude oil. We have studied various design parameters of SLIPS that can maximize the drag reduction performance. Our results showed that SLIPS is promising in reducing drag for various industrial fluid transport applications. Poster 96 _____________________________________________________________________ Spectroscopic Evidences of Atomic Hydrogen Adsorption via Spillover Effect on Metal-Organic Framework Catalysts C-Y. Wang, Q. Gong, J. Li, A. Lueking Abstract: Metal-organic frameworks (MOFs) are high surface area materials with the characteristics of adjustable structure and surface chemistry. It becomes a promising candidate for hydrogen storage, gas separation, and catalyst support. In this work, we focus on texture properties of as-synthesized MOF composites, and ex-situ spectroscopy of the materials after room-temperature hydrogen storage. The purpose is to examine different methods to synthesize catalyst-MOF composites without possible structural degradation, and to further determine favorable atomic H adsorption sites for better future MOF design strategy.

Three different MOFs are explored for various catalytic doping methods: IRMOF-8, Cu-BTC, and Cu-TDPAT. After comparing and identifying the feasible catalytic doping technique that maximizes stability and retains the surface area of the MOF precursor, we measure hydrogen uptakes at 300 K. It demonstrates catalyst addition significantly increases hydrogen storage via the hydrogen spillover effect, mostly pronounced at low pressure.

Among different MOFs and metal doping techniques, Cu-TDPAT with catalyst Pt/AC via pre-bridge addition method shows outstanding H2 adsorption. Novel hydrogen chemisorption sites are identified using spectroscopic techniques after comparing both undoped and doped MOFs in IR and XPS. With spectroscopy and density functional theory, we have improved mechanistic understanding of the hydrogen spillover effect developed by tracking of hydrogenation of N groups and H in metal-organic joints. Adoption of amino functional groups in organic ligand and Cu paddlewheel in metal cluster is one direction of designing MOF catalysts for ambient temperature hydrogen storage via spillover effect. Poster 97 _____________________________________________________________________ Bioinspired Omniphobic Slippery Coatings on Industrial-relevant Metals J. Wang, K. Kato, N. Sun, A. Blois, T-S. Wong Abstract: Common industrial metals, such as stainless steel, titanium, copper, and aluminum are widely utilized in numerous industrial and medical applications, ranging from oil-transport pipelines, airplanes, to hypodermic needles and medical implants. However, many of the state-of-the-art surface coatings on these metals are still far from optimal: they create drag for fuel transport, nucleate ice on airplanes, and trigger fouling on marine vessels. Here, we report a simple, robust, and scalable manufacturing strategy to create omniphobic coatings onto common stainless steels, titanium, copper, and aluminum based on the concept of slippery liquid-infused porous surfaces (SLIPS). The coatings can be applied onto different geometries, ranging from flat surface to the interior and exterior of tubes. Furthermore, our bioinspired coating is effective in repelling simple and complex fluids (e.g., blood), fluids of low-surface tensions such as pentane, as well as demonstrating anti-fouling and anti-corrosion characteristics. Detailed characterizations of the slippery coatings on metals will be reported in the meeting. Poster 98 _____________________________________________________________________ Ion-Beam Assisted Thin Film Growth by Biased Target Deposition H. Basantani, F. Aronovich, M. Horn, W. Drawl, S. Trolier-McKinstry

Abstract: Conventional sputter deposition methods such as magnetron sputtering and ion- beam deposition offer limited control over the adatom energy required in tailoring the microstructure, roughness, density and the intrinsic stress of a growing thin film. In magnetron sputtering, at typical pressures > 1mTorr, the adatom energy of the deposited species is 2-3 eV; whereas in ion-beam deposition the adatom energy is usually > 12 eV. This work focusses on thin films deposited by a novel technique known as the biased target deposition (BTD). BTD allows for secondary conditioning of the growing film by an ion beam capable of producing ions with energies between 10-50 eV at pressures <1mTorr. In this work, ultra-thin (< 5 nm), continuous films of Ni and Au have been investigated. Smooth films of Au and Ni have been repeatedly deposited with an rms roughness of ≈ 5 Å for Au and ≈1.3 Å for Ni. The ion assist was also used to deposit dielectric materials such as SiO2 and HfO2. Thin films of HfO2 (5 nm, 10 nm and 20 nm) have been deposited with a leakage current density < 5 ⨯ 10-7 A/cm2 at 2 MV/cm. In BTD, because the plasma is remotely generated, magnetic materials which are difficult to sputter by magnetron sputtering can be easily deposited. We have investigated magnetostrictive materials such as Terfenol-D and Galfenol. Initial results show promising magnetization of deposited films with a magnetization B > 0.13 T at a saturation field H < 10 Oe.

Materials Day 2013

42

Poster 99 _____________________________________________________________________ Templated Growth of Amorphous Carbon Films D. Keefer, J. Badding Abstract: Amorphous carbon materials take advantage of carbon’s ability to exist in different bonding environments. By combining both sp2 and sp3 bonding in differing amounts, control of the material’s properties can be tuned from graphite-like to diamond-like. The graphite-like materials take advantage of its metallic behavior and have been used to provide conductive coatings. Because of its high strength and optical transparency, diamond-like carbon has been used as clean protective coating against abrasion. Amorphous sp2 carbon wires have been deposited via a high pressure CVD technique into microstructured silica capillaries. A unique aspect of this deposition is that the wires are grown annularly from the outside in. These carbon wires have similar tensile strength to carbon fibers made by other techniques. sp3 carbon is challenging to deposit due to the large thermodynamic stability of graphite. To overcome this barrier, a plasma-enhanced microcapillary CVD system was developed. This has enabled the deposition of polymeric carbon films in microcapillaries with high sp3 and hydrogen content. Characterization of these films is ongoing with attempts to decrease hydrogen content while maintaining the sp3 carbon content to make harder materials. Future work will involve deposition of materials with high sp3 and low hydrogen content for possible application as an ultra-hard material. Poster 100 ____________________________________________________________________ Kinetics and Universality of Gate Adsorption in Flexible Metal-organic Frameworks for Gas Trapping S. Sircar, A. Lueking Abstract: Advancing gas separation technologies in a variety of present and emerging industrial applications can increase energy efficiency. Typically, gas separations are critical to industrial processes like oxy-combustion, syngas purification, natural gas purification, CO2 capture, H2 separations etc. Perhaps the most common is the classical air separations problem. Conventional cryogenic methods for air separation involve significant parasitic energy losses. We explore a novel trapping mechanism with potential for gas storage and separations by collaborating experimental and theoretical approach. The mechanism is based on a ‘gate-opening’ (GO) phenomenon common to flexible metal-organic framework (MOF) materials. Our findings indicate that utilizing GO-MOFs as adsorbents, in which gas-surface interaction dictate the diffusion rates into the material may help reduce these losses by as much as four fold. We show how accounting for gradual change in diffusivity of a gas into the material over the course of the experiment may lead to drastically enhanced capacities, unusual hysteresis and isotherm shapes. Such diffusion-limited evolution of gases could be harnessed for kinetic separations. Investigation of a kinetically limited regime with thermodynamic limitations represents a shift from 'traditional' solid state adsorbents. Single component adsorption studies suggest that gas selectivity ratios approaching infinity may be achievable for mixtures.

GO is when molecular gates in the structure expand/contract in response to the activation/de-activation of a switch or a thermodynamic driving. GO is characterized by an S-shaped isotherm i.e. negligible initial adsorption, followed by a steep rise when the switch is activated, and ultimately, a large adsorption-desorption hysteresis. According to our analysis, concentration-dependent diffusion coupled with insufficient equilibration, exacerbated at low temperatures and pressures, can explain all features of the isotherms for classical gases. Smaller molecules (H2) show enhanced capacity and behave differently. Stimulated by prior work in adsorption universality, we investigated the energetics of the process and found that transformations observed for certain gases can be mapped to predict behavior for other adsorbates. For data collection, we use both low and high pressure adsorption volumetric units. In the commercially available low pressure unit, we increased the frequency of stability checks, a deliberate manipulation to achieve a more stringent stability criterion. We also upgraded our custom-built high pressure adsorption unit by formulating new analytical data processing techniques to overcome the conventional and unresolved issues related to establishing a null baseline with Helium. Impact of random and systematic calibration errors was significantly reduced. Poster 101 ____________________________________________________________________ Chemotactic Separation of Enzymes K. Dey, S. Das, M. Poyton, S. Sengupta, P. Cremer, A. Sen Abstract: We demonstrate spontaneous separation of active enzyme molecules from a mixture based on their chemotactic response towards an imposed substrate concentration gradient. The separation is observed within a two-inlet-five-outlet microfluidic network, designed to allow mixture of active and inactive enzymes, each labeled with different fluorophores, to flow through one of its inlets. Substrate solution prepared in buffer was then introduced through the other inlet at the same flow rate. The steady state concentration profiles of the enzymes at specific positions along the length of the micro-channel were measured using a highly sensitive fluorescence microscope. In presence of a substrate concentration gradient, active enzyme molecules migrated more within the substrate channel compared to the inactive ones. For each of the outlets, the separation was quantified in terms of a separation coefficient. The experiments were repeated with different combinations of enzymes at different experimental conditions. Coupling the physics of laminar flow of liquid and diffusion of species in fluid, multiphysics simulations were developed to estimate the maximum possible separation for the given set of experimental conditions. Our results show that with appropriate microfluidic arrangement, molecular chemotaxis may lead to spontaneous, inexpensive, rapid and stress free separation protocols for active biomolecules.

Materials Day 2013

43

Poster 102 ____________________________________________________________________ Topological Phases in InAs/GaSb Type II Quantum Wells C. Liu Abstract: A topological phase is a new quantum state of matter that has an energy gap in the bulk, but topologically robust metallic states at the edge. In this work, we study topological phases in the systems of InAs and GaSb, two conventional III-V compound semiconductors. We predicted the quantum spin Hall effect, a novel topological phase that is protected by time reversal symmetry, in the so-called type II quantum wells made from InAs, GaSb, and AlSb, which has been recently confirmed in transport experiments. Furthermore, we show that with additional magnetic doping, this system will exhibit the quantum anomalous Hall effect, another topological phenomenon in magnetic systems that break time reversal symmetry. The realization of the quantum spin Hall effect and the quantum anomalous Hall effect in InAs/GaSb type II quantum wells will integrate topological physics into the conventional semiconductor systems and pave the way to the electronics with low or even no energy dissipation.

Poster 103 ____________________________________________________________________ Two-dimensional Layered Materials J. Zhu Abstract: This poster will provide an overview of the Zhu lab effort on two-dimensional layered materials including graphene and transition metal dichalcogenide such as WS2, MoS2 and WSe2. We synthesize and prepare high-quality layered material based devices using CVD and exfoliation and a variety of substrates and gate dielectrics such as SiO2, HfO2 and h-BN. Advanced lithography techniques allow us to define ribbons, Hall bars, and multiple gated structures to study the effect of adatoms, quantum confinement, electron-electron interaction, tunneling, and potential modulation. We examine the unusual physical properties of layered materials with transport, magnetotransport, and scanned probe microscopy. Poster 104 ____________________________________________________________________ Low Dimensional Systems and Their Composites for New Technologies K. Adu, D. Ma, P. Shetty, D. Hess, D. Capliger, R.Bell Abstract: Since the discovery of carbon nanotubes (CNT) in 1991 and the subsequent synthesis of semiconducting nanowires in 1998, these systems have added new paradigm tonanomaterials research and continue to expand our understanding of one-dimensional systems and their importance in the emerging nanotechnologies. We will present an overview of our current research endeavors in the forefront of fundamental and applied research in engineering nanoscale materials for new technologies. The research areas include magneto-plasmon photonics in metal-elastomer composites, transport in Al-CNT and MgB2-CNT composites, CNT-based electrodes for energy storage and conversion systems, and effect of size-induced confinement in phonon states of semiconducting nanowires.

This work is supported by Penn State Altoona and the Materials Research Institute at University Park Poster 105 ____________________________________________________________________ Ultrathin Self-assembled Single-walled Carbon Nanotube Electrodes for Design of Flexible Electrochemical Capacitors D. Ma, C.Randall, R. Rajagopalan, K. Adu Abstract: Binder free single-walled carbon nanotubes were self-assembled to form a highly dense 20-μm-thick carbon nanotube electrode to be used in electrochemical capacitors. Fabrication of symmetric nanotube capacitors using these electrodes and highly ionically conducting polyvinyl alcohol based hydrogel membranes soaked in aqueous sulfuric acid resulted in a capacitor with power density as high as 1040 kW/kg based on the mass of both electrodes. The capacitors showed no degradation in performance even after 10,000 cycles. Pseudocapacitance was further induced by modifying the surface of nanotube electrodes to almost double the specific capacitance while retaining the high power and cycling performance. Furthermore, all solid state electrochemical capacitors using the as-prepared carbon nanotube electrodes and polyvinyl alcohol/phosphoric acid polymer electrolyte were assembled and tested under various temperatures. The capacitors functioned well even at a high temperature of 100oC with less than 10% of capacitance decrease, which has applications in environmental friendly, flexible, and light-weighted energy storage devices with distinct features including fast charge/discharge rate, stable cycling behavior and high power density.

Materials Day 2013

44

Poster 106 ____________________________________________________________________ Shape-controlled Synthesis of Semiconducting SnS Nanocrystals and Evidence for a Structural Distortion at the Nanoscale A. Biacchi, D. Vaughn II, R. Schaak Abstract: The synthesis of colloidal semiconducting nanocrystals with controlled size, structure, and morphology using solution-based methods has emerged as an extremely active field of research due to their excellent properties, which allow for their applicability in many fields. Tin (II) sulfide is a narrow band gap semiconductor that has received markedly less attention than other related compounds despite its non-toxic and earth-abundant constituent elements, as well as its comparably low cost and favorable electrical properties.

Here we present a route for the solution synthesis of monodisperse colloidal SnS nanocubes and nanospheres in high yield. Further, detailed crystallographic characterization of these nanocrystals indicates that their atomic structure deviates from reported bulk phases. Finally, we show that their electronic and photocatalytic properties of these quantum dots are both shape-dependent and distinct from bulk SnS.

Poster 107 ____________________________________________________________________ Engineering Spontaneous Phenomena A. Drew, Bishop Group Abstract: From a thermodynamic perspective, a spontaneous process is that which proceeds without external direction – increasing the entropy of the universe in accordance with the second law. In general, such processes do not serve useful functions or yield desirable products – e.g., useful energy degrades into increasingly useless forms (namely, heat); complex molecular structures fall apart; structured materials become increasingly homogeneous.

On the other hand, engineering refers to the acquisition and application of knowledge to design and build structures and processes that perform functions beneficial to society. While inherently useful, engineered structures seldom organize spontaneously. Indeed, they more often require meticulous external guidance – e.g., the billions of transistors in a microprocessor are fabricated only through hundreds of carefully choreographed lithographic, etching, and deposition steps.

The unifying theme of our research is the integration of these somewhat contradictory concepts to engineer spontaneous phenomena. More specifically,

We design structures and materials that build themselves (self-assembly). We develop methods to direct and control physicochemical processes. We seek to understand self-organization in nonequilibrium systems. Through these pursuits, we find inspiration in biological systems, which supply us with many –almost miraculous – examples

of self-organizations and spontaneous functionality. Poster 108 ____________________________________________________________________ Two-dimensional Materials & Devices S. Eichfeld, G. Bhimanapati, P. Browning, C. Lee, Y. Lin, M. Hollander, T. Miyagi, J. Distefano, L. Hossain, K. Zhang, D. Kozuch, A. Alonso, and J. Robinson Abstract: The isolation of graphene (one atomic layer of carbon) constitutes a new paradigm in next generation electronic technologies, and even though graphene is considered transformational, it is only the “tip of the iceberg.” Transition metal dichalcogenides (TMDs) could have an even greater impact on next generation technologies once the chemical techniques to produce and tailor defect-free atomic layers are developed. Our research focuses on two-imensional material systems including graphene, hexagonal boron nitride (hBN), and transition-metal dichalcogenides (TMDs) with a wide variety of electronic and optoelectronic properties (semiconducting to superconducting). This poster briefly summarizes our development of synthesis techniques for the production of high quality films, characterization of these materials to determine process/property relationships, and devices to exploit the unique properties of these materials. Poster 109 ____________________________________________________________________ Dispersion Strategies and Role of Interfacial Phenomena in Polymer Nanocomposites P.Khodaparast, Z. Ounaies Abstract: Owing to unique characteristics of nanoparticles such as high surface to volume ratio, it is postulated that nanoparticle-modified polymers exhibit properties beyond those predicted by effective media theories. In the case of dielectric nanoparticles in a polymer, it is expected that dielectric properties of the obtained nanocomposite will be dominated by the role of interface rather than predicted by the inherent properties of individual components. Despite several studies on dielectric behavior of polymer nanocomposites, the true underlying mechanism(s) for controlling the final dielectric properties is not yet understood. The hypothesis is that the nature of interfacial region is not only influenced by high surface area at the nanoscale, but is also governed by intrinsic properties of both polymer and nanoparticles and their interaction at nano- and micro-scale regimes. This research will focus on

Materials Day 2013

45

understanding the role of important parameters such as physical, chemical, and surface properties of nanoparticles and polymers in affecting the quality of dispersion and nature of interphase, which in turn will affect the final dielectric properties. Polyvinylidene fluoride, PVDF, is chosen as the main polymer under study because it has a high dielectric constant among polymers. Different metallic oxides including: titania, silica and alumina are chosen as the nanoparticle phase. The effect of dispersion, particle surface chemistry and hence particle-polymer chemical interaction will be investigated by the change of nanoparticle type and chemical modification of nanoparticle surface via silane-coupling agents. The effect of particles physics will be studied by considering different particle type and crystallinity. Ultimately, the effect of particle dispersion, chemistry and physics are all combined to reach to a better understanding over the nature of interphase and its principal behavior on final dielectric properties. Poster 110 ____________________________________________________________________ Vertical Nanowire Assembly Directed by Lithographic Microwells D. Kirby, B. Smith, A. Wustrow, C. Keating Abstract: Nanowires have many exciting properties (light absorptivity, strain relaxation, aspect ratio) that have made them targets for new energy collection and storage materials. Assembly strategies to develop these materials provide opportunities to incorporate a wide variety of materials, treat particles separately from the substrate, and combine multiple particle types into the same structure. Designing these materials will require a detailed knowledge of the fundamental forces (electrostatics, van der Waals) at play between the particles themselves and the underlying surface. Here we examine the assembly of partially etched nanowires,which are a hybrid nanotube/nanowire with a partial metal (Au, Pd, Pt, Rh) core and etched hollow silica segment, ~300 nm in diameter and 2-12 μm in length. When these particles are allowed to sediment from suspension onto a glass coverslip they form arrays where approximately 70% of the particles are vertically oriented, depending on the dimensions of the two segments. We have also developed a strategy to create particle dense vertical arrays using lithographic patterning to position and orient assemblies of a desired size on a surface. We have explored the two contributions to the assembly mechanism and the effect of decreasing microwell size on array quality. As the microwell edge dimensions approached the partially etched nanowire length, many wells were observed to contain 100% of their particles in the vertical orientation while entire arrays increased to ~92% standing. Using small microwell dimensions we were able to induce standing for solid nanowires, (without an etched segment) that assemble parallel to a planar substrate. We have also investigated the assembly of mixed nanowire populations which show potential for designing new reconfigurable materials systems. Finally, to work toward further processing and device integration we studied removal of the assembly solvent, a process made possible as microwells protected the structures from destructive currents generated during evaporation. Poster 111 ____________________________________________________________________ Theory of Proximity Induced Triplet Superconductivity in Spin-orbit-coupled Systems X. Liu, J. Jain, and C-X. Liu Abstract: We study proximity induced triplet superconductivity in a spin-orbit-coupled system, and show that the triplet-paring function can be controlled by varying the relative strengths of the Rashba and Dresselhaus spin-orbit couplings in a two-dimensional system. In particular, a long range triplet-helix mode is predicted when two couplings are equal. A transition between 0 and π triplet Josephson junctions can be induced by varying spin-orbit coupling strength. An experimental setup is proposed to verify these effects, the observation of which can serve as a direct confirmation of the triplet nature of the proximity induced superconductivity. Poster 112 ____________________________________________________________________ Metal Phosphide and Chalcogenide Electrocatalysts for Clean Energy Technologies E. Popczun, R. Schaak Abstract: The production of molecular hydrogen by the electrochemical reduction of water is an important component of several developing clean-energy technologies. The hydrogen evolution reaction (HER) is effectively facilitated by noble metals such as Pt, which generate large cathodic current densities for this reaction at low overpotentials. Replacement of Pt with earth-abundant metals would be desirable to facilitate the global scalability of such potential clean-energy technologies. Nanoparticles of nickel phosphide (Ni2P) have been investigated for electrocatalytic activity and stability for the HER in acidic solutions, under which proton exchange membrane based electrolysis is operational. The catalytically active Ni2P nanoparticles were hollow and faceted to expose a high density of the Ni2P(001) surface, which has previously been predicted based on theory to be an active HER catalyst. The Ni2P nanoparticles had among the highest HER activity of any non-noble metal electrocatalyst reported to date, producing H2(g) with nearly quantitative faradaic yield, while also affording stability in aqueous acidic media. We have also identified additional systems that show promising HER activity, including CoP and Co3S4.

Materials Day 2013

46

Poster 113 ____________________________________________________________________ Applications of Conformal Thin Films on Non-traditional/Non-planar Substrates D. Pulsifer, A. Lakhtakia Abstract: Here I present three novel applications of conformal thin films on non-traditional/non-planar substrates. For the first application, a visual lure designed to attract the destructive emerald ash borer was fabricated through a process by which the upper surface of the beetle was directly replicated. This process required the conformal coating of the beetle with a nickel thin film which was later reinforced to produce a die from which multiple replicas could be produced by patterning a polymer sheet which matched the color of the original beetle. For the second application a conformal coating process was developed which makes fingerprints visible for use as forensic evidence. This was done by producing a film with columnar morphology over both the fingerprint and the underlying substrate. This technique was compared to several traditional development techniques on many substrates and found to produce superior development for many of those substrates including challenging substrates such as discharged cartridge casings. For the third application, a zinc-selenide chiral sculptured thin film was deposited on a magnesium-fluoride grating. This interface allowed for the first experimental observation of a new type of electromagnetic surface wave, called the Dyakonov-Tamm wave, in the grating-coupled configuration. Poster 114 ____________________________________________________________________ Processing Pathways for Silicon Micro/Nanowire Array Solar Cells Redwing Group Abstract: We are investigating unique fabrication pathways for Si micro/nanowire arrays that exploit the advantages of the radial geometry and utilize lower cost processing methods. In a radial junction cell, light absorption is decoupled from the collection of photogenerated carriers into orthogonal spatial directions. Consequently, unlike in conventional planar solar cells, photogenerated minority carriers with shorter diffusion lengths can be effectively collected radially enabling the use of lower purity, less expensive Si material. In addition to improved carrier collection, through appropriate design and photon management in wire array geometries, it is possible to obtain enhanced light absorption and to extend the optical path length beyond the classical limit.

Our research on this project includes three main parts. The first part is the use of aluminum instead of gold as the catalyst for Si nanowire growth. Aluminum is an interesting metal for photovoltaic applications since it is low cost and is a shallow acceptor in Si. Our studies have demonstrated that epitaxial Si nanowires can be grown using Al metal catalysts through the use of high H2 and SiH4 partial pressures which effectively reduce Al2O3. The second part is the conformal deposition of ultra-thin amorphous Si n/i. Si hetero junction with intrinsic thin layer (HIT) structure offers good surface passivation on crystal Si surface and leads to high Voc. Meanwhile, the amorphous Si thin layers can be deposited by plasma enhanced CVD (PECVD) at low temperature (~200 oC), which is compatible with heat sensitive substrate such as glass. Improved carriers collection with high Voc (600 mV even without heavily doped back surface-field) has been achieved on pillar array devices from materials with short minority carrier diffusion length. The third part is the growth of vertical Si nanowires on glass using (111) Si template layers formed by aluminum-induced crystallization. Glass is an ideal low cost substrate for Si micro/nanowire array solar cells, however, its morphous nature results in nanowires that grow in random directions off of the substrate. We are investigating the formation of thin, polycrystalline Si (111) layers on glass using aluminum-induced crystallization (AIC) which can serve as templates for vertical nanowire growth. Poster 115 ____________________________________________________________________ Adaptive and Responsive Nanoparticle Amphiphiles K. Bishop, H-Y. Lee, S. Shin Abstract: The ability to functionalize nanoscale colloids with specific patterns of hydrophobic and hydrophilic surface regions remains an outstanding challenge in materials chemistry. Like molecular amphiphiles (e.g., surfactants and peptides), amphiphilic particles are desirable both as surface active agents (e.g., for surface coatings or emulsion stabilization) and for their propensity to self-assemble into higher order structures such as clusters, fibers, and lattices. Unlike their molecular analogs, however, amphiphilic nanoparticles (NPs) decorated with mixed monolayers of hydrophobic and hydrophilic ligands have the ability to both adapt their surface chemistry in response to environmental changes and respond to external fields acting on the particle cores. These unique capabilities will enable new strategies for nanoscale self-assembly using adaptive interactions, field responsive vesicles incorporating amphiphilic NPs, and magnetic surfactants with dynamically tunable surface activity. Poster 116 ____________________________________________________________________ Nanofabrication Laboratory: An MRI Shared User Facility Abstract: Penn State’s Nanofabrication Laboratory (Nanofab) is a full-service user facility providing faculty, students, and industry researchers the opportunity to perform hands-on research with some of the world’s most sophisticated instruments for micro- and nano-fabrication. The Nanofab’s technical support staff offers expertise in a wide range of fabrication techniques, with a primary focus on complex ferroelectric oxide materials and device development, amorphous, infrared, and organic thin film materials and devices, nanowire synthesis and directed assembly, and graphene materials and device process development.

Materials Day 2013

47

Poster 117 ____________________________________________________________________ Center for 2-Dimensional and Layered Materials at Penn State M. Terrones, J. Robinson Abstract: Graphene has been of great interest in recent years due to its unique physical and electrical properties. This has sparked research into other layered materials systems, including hexagonal boron nitride (h-BN) and transition metal dichalcogenides (TMDs). These materials exhibit properties ranging from insulating to semiconducting and allow for the possibility of unprecedented electronic, optical, chemical and magnetic properties, which provide the means to considerably impact any number of technology applications. The goal of the center is to develop a fundamental understanding of the synthesis and materials performance limits of 2-D layered structures. This includes development of synthesis techniques for large-area synthesis of highly crystalline 2-D layered materials exhibiting tunable band gaps, and novel low-cost doping techniques to tailor the electronic, structural, and chemical properties of 2-D layered materials. Through characterization and correlation of the process/property relationship of these layered materials the center aims to understand the fundamental impact of bulk, edge, and interface states on the chemical and electronic properties and how to control these states to enhance specific materials properties. Poster 118 ____________________________________________________________________ Hybrid Ferromagnetic/Semiconducting Nanowires for Nano-spintronics J. Kally, S. Yu, D. Kim, S. Tadigadapa, S. Mohney, M. Chan, N. Samarth Abstract: The recent inclusion of spin-based functionality into semiconducting nanostructures through the fabrication of ferromagnet-coated semiconducting nanowires has provided an avenue to study material interactions and possible spin injection in a quasi-one dimensional system. Utilizing two connected molecular beam epitaxy (MBE) chambers (III-V and II-VI) provides exciting possibilities for the growth of topological insulators and ferromagnetic heterostructures in a strained nanowire geometry. The main nanostructures we study are based on GaAs nanowires grown by the previously established technique of catalyst-free growth in a MBE system. Spin functionality is then added to these nanowires by the thin-film growth of MnAs, which is ferromagnetic at room temperature. The resulting nanowires are then characterized by electrical measurements in a magnetic field and structurally analyzed by transmission electron microscopy. Novel thermal transport measurements will then be performed on these nanowires using a thermal workbench. This pursuit should yield a better understanding of the materials physics in a confined structure and allow for the possibility of incorporating spintronic nanowire devices into electronic devices. Poster 119 ____________________________________________________________________ Mechanochemistry of Carbon Cages to Explore C-H Interactions P. Ray, E. Xu, T. Fitzgibbons, A. Lueking, J. Badding,V. Crespi Abstract: Nanostructured carbon materials have received a lot of attention because of their applications in hydrogen storage; however, poor understanding of C-H interactions deprives these materials from reaching the current DOE goals. Use of mechanochemistry of carbon cages in presence of H2 to probe hydrogen penetration in cages is a novel concept. Under high pressure, aromatic and polyaromatic systems rehybridize from sp2 to sp3 states to minimize the activation volume. To better understand C-H interactions on carbon cages, we investigate the formation of novel forms of carbon under extremely high pressure. Multiwavelength in-situ Raman spectroscopy is utilized to probe structural changes in the carbon backbone with special focus on molecules with internal free volume and hydrogenated buckyballs. Poster 120 ____________________________________________________________________ Polarization-independent Broadband Absorber Based on Engineered Nanostructures Y. Yuwen, L. Lin, F. Namin, J. Bossard, L. Liu, D. Werner, T. Mayer AbsractElectromagnetic absorbers have wide applications from radio-frequency through optical regimes. However, the performance of most existing absorbers has limited absorption band due to the conventional design and fabrication approach. Here we investigated and demonstrated the performance of two optimized broadband absorbers in the mid-infrared range by utilizing Genetic Algorithm and in the visible range based on the aperiod quasicrystal plasmonic structures.

Materials Day 2013

48

Poster Session Map ____________________________________________________________

Alumni Hall, Hetzel Union Building

Materials Day 2013

49

Notes ________________________________________________________________________