Phosphorene and 2D Companions

Roma, May 8th 2017

CNR, Sala Marconi, Piazzale Aldo Moro 7, Roma

“The event has been organized in the framework of the ERC Advanced project PHOSFUN (grant agreement n°670173) under the European Union’s Horizon 2020 research and innovation programme“

For further information please visit: http://phosphoreneand2dcompanions.nano.cnr.it/

Program & Book of Abstracts

PROGRAM 9:30 – 10:20 Registration 10:20 – 10:50 Opening address and welcome:

- Prof. Massimo Inguscio (President of National Research Council) - Dr. Maurizio Peruzzini (Director of Department of Chemical

Sciences and Materials Technology) - Dr. Corrado Spinella (Director of Physical Sciences and Technologies of Matter)

10:50 – 11:30 Plenary Lecture: Dr. Miriam S. Vitiello (CNR-NANO, Pisa) Title:

Terahertz Photonic devices exploiting bidimensional materials and heterostructures"

11:30 – 12:00 Coffee Break 12:00 – 13:00 Session I: Six Oral Communications 12:00 – 12:10 A. Lorenzoni “Multiscale molecular modeling of surface

anisotropy and electronic properties of phosphorene” 12:10 – 12:20 A. Mezzi “Characterization of 2D materials by surface

spectroscopies” 12:20 – 12:30 G. Profeta “Evolution of electronic structure from few-layer

phosphorene to black phosphorous” 12:30 – 12:40 E. Rotunno “The influence of crystallographic defects on the

optical properties of MoS2” 12:40 – 12:50 L. Ottaviano “Layer identification and engineering of

mechanically exfoliated MoS2” 12.50 – 13:00 A. Martone “Preparation and Characterization of Graphite

Nanoplatelet Nanolaminates” 13:00 – 14:10 Light lunch 14:00 – 14:40 Plenary Lecture: Dr. Vincenzo Palermo (CNR-ISOF, Bologna)

Title: “Covalent and Supramolecular Chemistry of Organic Molecules with Graphene and Other 2D Materials”

14:40 – 16:00 Session II: Eight Oral Communications 14.40 – 14:50 M. Cavallini “Fabrication of complex functional structures

from 2D materials by unconventional lithography” 14:50 – 15:00 F. Cicogna “Polymer-based BP nanocomposites: preparation,

characterization and properties”

Program -Part I -

15:00 – 15:10 F. d’Acapito “ Structural characterization of 2D X-ene sheets by X-ray asorption Spectroscopy (XAS)”

15:10 – 15:20 C. Cantalini “Perspectives of 2D materials in gas sensing applications”

15:20 – 15:30 R. Flammini “ The Sb-ene/Bi2Se3 interface: a route to investigating the proximity effect?”

15:30 – 15:40 A. Kumar “STM studies of exfoliated black Phosphorus” 15:40 – 15:50 C. Grazianetti “The route to X-enes transistors: from silicone to

phosphorene” 15:50 – 16:00 G. Nicotra “Electronic and structural properties of BP and

MoS2 at high energy and spatial resolution” 16:00 – 16:20 Coffee Break 16:20 – 17:20 Session III: Six Oral Communications 16:20 – 16:30 G. Greco “ Key enabling processes for novel high frequency

devices based on 2D materials integration with Nitride semiconductors”

16:30 – 16:40 A. Ienco “How to Decorate Phosphorene with Metal Fragments”

16:40 – 16:50 D. Scelta “High-pressure structure and reactivity of Phosphorus allotropes”

16:50 – 17:00 G. Giambastiani “Unravelling Surface basicity and Bulk Morphology of 2D Carbon-based Catalysts with Unique Dehydrogenation Performance”

17:00 – 17:10 G. Contini “Surface-confined polymerization as emerging technology for electronic devices”

17:10 – 17:20 M. G. Raucci “Cellular behaviour on few layer black phosphorus for tissue engineering”

17:20 – 17:40 Concluding Remarks

Program -Part II -

Multiscale molecular modeling of surface anisotropy and electronic properties of phosphorene

A. Lorenzoni1,2, M. Baldoni1,2, E. Besley2, M. Muccini1, F. Mercuri1

1ISMN-CNR, Via Piero Gobetti 101, Bologna (Italy) 2School of Chemistry, University of Nottingham, Nottingham (UK)

e-mail: francesco.mercuri@cnr.it

Phosphorene has been the focus of intense research efforts, mainly due to its distinct electronic properties, such as the direct band gap and high carrier mobility, which are influenced by its anisotropic structure. However, phosphorene also exhibits a high sensitivity to air and water and requires protection if it is to be used in device applications.

In this work, the surface anisotropy and electronic properties of phosphorene were investigated computationally using classical molecular dynamics (MD) and density functional based tight binding (DFTB) methods. MD simulations were performed to investigate the interface between phosphorene and poly(methyl methacrylate), PMMA, an organic polymer extensively used as dielectric or capping layer in organic devices, such as organic field-effect transistors (OFETs). It was found that phosphorene adheres and adapts to the corrugated surface of PMMA thus losing its planarity. The electronic properties of phosphorene on PMMA were evaluated and compared to the planar case, using DFTB calculations. This study allows us to understand how the electronic properties of phosphorene may be affected by the underlying substrate in possible devices.

MD simulations were also carried out to model the self-assembly of alkane chains on a phosphorene in order to investigate how the anisotropic nature of phosphorene surface affects the interaction with adsorbates. Upon equilibration at room temperature, alkane chains arrange along the direction of charge transport, i.e. along zig-zag direction of phosphorene, showing a remarkable anisotropy which drives the orientation of the supramolecular aggregates and inducing modification of the surface morphology at the interface.

Fig. 1. Interfaces between phosphorene and PMMA (left) and between alkane chains and phosphorene (right)

Book of Abstract

Characterization of 2D materials by surface spectroscopies

A. Mezzi1, S. Kaciulis1, M. Lavorgna2 1 ISMN – CNR, 00015 Monterotondo Stazione, Roma, Italy

2 IPCB – CNR, 80055 Portici, Napoli, Italy

In the last decade, the significant impact in science and technology of graphene-based materials with extraordinary electronic, optical and mechanical properties has given rise to a great impetus in development of new 2D materials, such as phosphorene, silicene, etc. Since the first research works in correspondence to the 2D technologies, a crucial role has been assigned to the characterization methodologies. For this purpose, the mostly used techniques are Raman spectroscopy, STEM, AFM, LEED and also surface analyses, such as Auger electron spectroscopy (AES), Ultra-Violet Photoelectron Spectroscopy (UPS) and X-ray Photoelectron Spectroscopy (XPS). Obviously, a combination of two or more analytical techniques permits to improve the characterization of 2D materials. In this work, will be presented an overview on the applications and future perspective of the characterization of 2D materials by electron spectroscopies: AES, UPS and XPS. It is well known, that XPS and AES are suitable to investigate the topmost monolayers on the surface of any solid-state material, providing information on the elemental concentration and chemistry, also on their lateral and in-depth distributions. The UPS is usually employed to investigate the valence band structure and the work function of conductive materials and semiconductors. All these techniques are extremely surface sensitive, therefore they are successfully employed to characterize 2D materials and also to determine the thickness of ultra-thin films. In this presentation, will be discussed the investigations carried out on graphene, GO and rGO based materials. The photoemission core level of C 1s (by XPS) and Auger C KVV line (by AES and XAES) have been studied to determine the quality of the graphene [1]. As it was demonstrated, from the shape of C KVV spectrum is possible to recognize the cases of pure sp2 and sp3 configurations, and even to quantify their ratio in amorphous carbon films. Since the fine structure of the C KVV Auger transition is strongly affected by electronic configuration of carbon near Fermi edge, the D parameter, defined as the distance between the most positive maximum and most negative minimum of the first derivative of C KLL spectrum [1], can be considered as a fingerprint of the atomic arrangement of C in sp2 and sp3 configuration. Moreover, the investigation of C KVV spectra excited by electron beam (AES) and X-ray photons (XAES) enables to recognize the presence of 2D carbon on different supports [1,2] and in various composites [3-5].

References [1] S. Kaciulis, A. Mezzi, P. Calvani, D.M. Trucchi, Surf. Interf. Anal., 46, 966 (2014). [2] L. Nobili, L. Magagnin, R. Bernasconi, F. Livolsi, L. Pedrazzetti, A. Lucotti, S.K. Balijepalli, A. Mezzi, S. Kaciulis, R. Montanari, Surf. Interf. Anal., 48, 456 (2016). [3] N. Yan, G. Buonocore, M. Lavorgna, et al., Composites Sci. Technol., 102, 74 (2014). [4] S. Kaciulis, A. Mezzi, S.K. Balijepalli, M. Lavorgna, H.S. Xia, Thin Solid Films, 581, 80 (2015). [5] L. Paliotta, G. De Bellis, A. Tamburrano, et al., Carbon, 89, 260 (2015).

Book of Abstract

Evolution of electronic structure from few-layer phosphorene to black phosphorous

G. Profeta1, N. Ehlen2, B. V. Senkovskiy2, A. V. Fedorov,2, A. Perucchi3, P. Di Pietro3,

A. Sanna4, L. Petaccia3 and A. Gruneis2

1 Department of Physical and Chemical Sciences and SPIN-CNR, University of L’Aquila, Via Vetoio 10, I-67100 Coppito, Italy

2 1II. Physikalisches Institut, Universitat zu Koln, Zulpicher Strasse 77, 50937 Koln, Germany 3 Elettra Sincrotrone Trieste, Strada Statale 14 km 163.5, 34149 Trieste, Italy

4Max-Planck-Institut fu ̈r Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany e-mail: gianni.profeta@aquila.infn.it

A complete set of tight-binding parameters for the description of the quasiparticle dispersion relations of black phosphorous (BP) and N -layer phosphorene with N = 1 . . . ∞ is presented. The parameters, which describe valence and conduction bands, are fit to angle-resolved photoemission spectroscopy (ARPES) data of pristine and lithium doped BP. We show that zone-folding of the experimental three-dimensional electronic band structure of BP is a simple and intuitive method to obtain the layer-dependent two-dimensional electronic structure of few-layer phosphorene. Zone folding yields the band gap of N-layer phosphorene in excellent quantitative agreement to experiments and ab initio calculations. A combined analysis of optical absorption and ARPES spectra of pristine and doped BP is used to estimate a value for the exciton binding energy of BP[1]

References

[1] N. Ehlen et al, Phys. Rev. B 94, 245410 (2016)

Book of Abstract

The influence of crystallographic defects on the optical properties of MoS2

E. Rotunno1, F. Fabbri1,2, E. Cinquanta3, D. Campi4, D. Kaplan5, L. Lazzarini1, M. Bernasconi4, G. Nicotra6, A. Molle3, V. Swaminathan5 and G. Salviati1

1 IMEM-CNR Institute, Parco Area delle Scienze 37/A, 43124 Parma (Italy) 2. KET Lab, c/o Italian Space Agency via del Politecnico, 00133 Roma, Italy

3 Laboratorio MDM, IMM-CNR, via C. Olivetti 2, Agrate Brianza, I-20864, Italy 4 Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Via R. Cozzi 55, Milano, Italy

5 U.S. Army RDECOM-ARDEC, Fuze Precision Armaments and Technology Directorate, Picatinny Arsenal, New Jersey, USA

6 IMM-CNR Institute, Catania, Italy e-mail: enzo.rotunno@imem.cnr.it

Semiconducting transition metal dichalcogenides (TMDC), such as MoS2 or WS2, has emerged as a promising substitutes for graphene thanks to their superior properties and inexpensive production methods 1. The main advantage comes from quantum confinement effects that enable an indirect-to-direct band-gap transition in single layers that makes TMDC monolayers promising 2D semiconducting materials for nanoelectronic and optoelectronic applications2. The lattice defects in TMDCs, including point and line defects, have been mainly studied from a structural point of view, while their optical properties remain mostly unexplored. Therefore, the analysis of the crystal defects deserves a focused approach to understand how novel optical properties can be engineered by controlling the defect nucleation. In this work we report on the experimental evidence of near-infrared (NIR) emissions from crystalline defects in MoS2 multi-layer flakes exfoliated from bulk molybdenite via the conventional tape method. Different kinds of crystal defects have been investigated by Transmission Electron Microscopy (TEM), Electron Energy Loss Spectroscopy (EELS), microRaman spectroscopy, Cathodoluminescence (CL) spectroscopy complemented by ab-initio Density Functional Theory (DFT) calculations in order to assess their influence on the optical properties. In particular, the MoS2 flake’ edges present an intense emission peaked at about 0.75 eV that can be ascribed to the high concentration of sulfur vacancies (VS). Moreover, the massive presence of line defects induce a strong red-shift and broadening of the indirect band-to-band transition of MoS2, peaked at 1.25 eV3. Lastly, structural and compositional modifications induced by controlled electron beam irradiation experiments have been performed to understand how novel electronic and/or optical properties can be engineered by controlling the nucleation of crystal defects4.

References [1] Q.H. Wang, et al. Nat. Nanotech. 7, 699-712 (2012) [2] D. Sarkar et al. ACS Nano 4, 392-4003 2014 [3] F. Fabbri et al. Nature Comm. DOI: 10.1038/ncomms13044 [4] E. Rotunno et al. 2D Materials 3 2016 025024

Book of Abstract

Layer identification and engineering of mechanically exfoliated MoS2

L. Ottaviano1,2, S. Palleschi1, F. Perrozzi1, G. D’Olimpio1, F. Priante1, M. Nardone1, M. Gonchigsuren3, M. Gombosuren4, A. Lucia5, G. Moccia5, O. A. Cacioppo5

1Dipartimento di Scienze Fisiche e Chimiche (DSFC) Università dell'Aquila, Italy 2CNR-SPIN UOS L'Aquila, Italy

3School of Applied Sciences, MUST, Ulaanbaatar, Mongolia 4School of Physics and Electronics National University of Mongolia Ulaanbaatar, Mongolia

5LFoundry, a SMIC company, Avezzano, Italy e-mail: luca.ottaviano@aquila.infn.it

In this paper we accurately revisit the mechanical exfoliation (and layer number determination) of MoS2 (chosen as example 2D material due to the booming interest on it [1-3]). By modeling the exfoliation itself, as a random vertical (lateral) exfoliation (fragmentation) phenomenon, a rationale is given to optimize the number of iterations in the scotch-tape technique in order to produce the largest amount of mono-layer flakes with the largest average area. Experiments have been carried out with a unified complementary approach based on optical microscopy (to detect, via quantitative contrast analysis, candidates of few layer MoS2 deposited onto 270 nm SiO2/Si(100) substrates), Atomic Force Microscope, resonant and non-resonant Raman spectroscopy, and Photo-Luminescence spectroscopy. The experimental analysis has been focused on a statistically significant set of few-layer MoS2 flakes (from one to seven layers). The work stresses the strong need of such complementariness to really unambiguously determine the layer number of flakes (that neither optical microscopy, nor AFM alone can give). Optical microscopy experiments demonstrate that for few-layer MoS2 (from the mono to the epta-layer) the optical contrast is weakly depending on the radiation wavelength and is a non-monotonic function of the layer number. Accordingly flakes from ten to twelve layer thick exhibit the same contrast of monolayers, as demonstrated by parallel AFM analysis. AFM clearly shows that the stacking between the silicon oxide substrate and the first MoS2 layer is strongly unpredictable and likely depending on the degree of surface contaminants on the substrate. Raman analysis is proposed to validate, by means on non-resonant Raman spectroscopy the layer number, and for the first time a layer estimation number based on a quantitative analysis of resonant Raman and PL spectra is proposed. Finally, a method to engineer the layer number of few layer MoS2 flakes by means of air and vacuum thermal annealing is demonstrated [4]. References [1]“Few layer MoS2 lithography with AFM tip: description of the technique and nano-spectroscopy investigation”, M. Donarelli, F. Perrozzi, F. Bisti, F. Paparella, V. Feyer, A: Ponzoni, G. Munksaikhan, and L. Ottaviano, Nanoscale 7, 11453 (2015). [2]“Response to NO2 and other gases of resistive chemically exfoliated MoS2-based gas sensors” M. Donarelli, S. Prezioso, F. Perrozzi, F. Bisti, M. Nardone, L. Giancaterini, L. Cantalini, and L. Ottaviano, Sensors & Actuators 207, 602 (2015). [3]“Tunable sulphur desorption in exfoliated MoS2 by means of thermal annealing in ultra-high vacuum” M. Donarelli, F. Bisti, F. Perrozzi, and L. Ottaviano, Chem. Phys. Lett. 588, 198 (2013). [4] L. Ottaviano, S. Palleschi et at. (to be submitted).

Book of Abstract

Preparation and Characterization of Graphite Nanoplatelet Nanolaminates

A. Martone1, M. R. Ricciardi1, F. Cristiano2, F. Bertocchi2, M. Giordano1 1CNR-IPCB Institute for Composites, Polymers and Biomaterials, National Research Council of Italy, P.le E.

Fermi, 1 80055 Portici, NA, Italy 2Nanesa S.r.l. Via del Gavardello 52c 52100 Arezzo, Italy

e-mail: alfonso.martone@cnr.it

Among the different composite architectures, nanolaminates are emerging as interesting materials for structural and functional applications. Nanolaminates is a biomimetic architecture copying the structure of nacre consisting of assemblies of well-oriented nanoscopically thin laminae held together by a low content of matrix. At the state of the art, no attempt has been reported to manufacture a bulk material keeping nanolaminate structure. Here we report the manufacturing and the mechanical testing of a bulky composite at very high content of graphite nanoplatelet, GNP, made by the conventional lamination process of epoxy preimpregnated nano-laminates. In particular, an aeronautical grade epoxy resin (RTM6) has been chosen as the matrix of the preimpregnated nanolaminates that are constituted by the assembly of well-oriented nanoplatelets, GNPs. Com-position, morphology, tension and bending performance have been investigated for the single ply preimpregnated nanolaminate vary-ing the compaction pressure for two nominal matrix content (20 and 30% wt/wt. A macroscopic 6 plies (epoxy matrix content 30% wt/wt) laminate has been finally manufac-tured and tested, high mechanical modulus (32.5 GPa) and a damping capacity (tand = 0.030) higher than that of the matrix poly-mer.

a) b)

Figure 1 - a) Nanolaminate SEM image, 70% wt GNP, b) Tensile properties

This work was supported by European Union under grant agreement Graphene Flagship

References [1] D.F. Schmidt, Nanolaminates - Bioin-spired and beyond, Mater. Lett. 108 (2013) 328–335. [2] H. Wu, L.T. Drzal, Graphene nanoplate-let paper as a light-weight composite with excellent

electrical and thermal conduc-tivity and good gas barrier properties, Carbon N. Y. 50 (2012) 1135–1145.

[3] M.R. Begley, N.R. Philips, B.G. Comp-ton, D. V. Wilbrink, R.O. Ritchie, M. Utz, Micromechanical models to guide the development of synthetic “brick and mortar” composites, J. Mech. Phys. Sol-ids. 60 (2012)

Book of Abstract

Covalent and supramolecular chemistry of organic molecules with graphene and other 2d materials

A. Liscio, E. Treossi, Z. Xia, A. Kovtun, N. Mirotta, A. Scida, S. Dell’Elce, V. Palermo

CNR-ISOF, Bologna, Italy

Graphene exhibits exceptional mechanical, optical and electrical properties that are unfortunately accompanied by poor processability and poor tunability. While the outstanding physical properties of graphene are well known, the full potential of graphene chemistry has not yet been fully exploited. The properties of the graphene backbone can be tailored by making use of the many covalent and non-covalent approaches of carbon-based organic chemistry, thereby providing new functionalities to this already exceptional material, as well as enabling its large- scale production and solution processing. The controlled interaction of graphene with tailor-made organic semiconductors (OS) can offer a solution to solve simultaneously the problems of processing and functionalization. The use of well- chosen organic semiconducting molecules interacting with graphene, such as small polyaromatic dyes or polymers, enables an optimal control over the molecular self-assembly process forming low- dimensional graphene-organic architectures. Organic molecules shall interact with graphene in infinite ways, adsorbing on its surface to form ordered layers, or reacting chemically with it; conversely, graphene can be mixed with polymers, creating composites already used in large-scale applications at industrial level. Here, we give an overview of our work on graphene-organic composites with a particular focus on:

Ø Exfoliation and functionalization of graphene and other 2D materials using polyaromatic molecules.

Ø Electrochemical functionalization and processing of graphene. Ø Graphene-based composites for applications in mechanics, electronics and energy storage.

Beyond graphene, the same approach shall be used for a wide range of layered materials (BN, MoS2, MoSe2, WS2 etc.), featuring complementary conductive, semiconductive and insulating properties, opening the way to produce new composite, 2D meta-materials.

References 1. ChemPlusChem, (2017) 82, 358. 2. ACS Nano, (2016) 10, 7125. 3. Carbon, (2016) 96, 503. 4. Nanoscale, (2016) 8, 8749. 5. Nature Communications, (2016) 7, #11090. 6. 2d Materials, (2015) 2, 030205 7. Nanoscale, (2013) 5, 4205. 8. Materials Matters-Sigma Aldrich (open access), (2015) 11, 45. 9. Graphene Factory http://grafene.cnr.it/

Book of Abstract

Fabrication of complex functional structures from 2D materials by unconventional lithography

D. Gentili1, Z. Hemmatian1,2, A. Riminucci1, M. Cavallini1* 1 CNR - Istituto per lo Studio dei Materiali Nanostrutturati (CNR-ISMN).

2 Present adress: University of California, Santa Cruz (US) Dept. of Electrical Engineering, e-mail: m.cavallini@bo.ismn.cnr.it

The fabrication and positioning of micro- nano structures made of functional materials is of crucial importance in a wide range of fundamental and technological applications, thus there is an increasing requirement for developing a shared technological platform able to process materials from solutions on large areas. This need is particularly relevant for 2D materials that are difficult to process by conventional methods. Here we report on the application of an unconventional soft lithographic method, known as lithographically controlled wetting(LCW)[1]. LCW is used to pattern 2D materials on technologically relevant surfaces. This process exploits the self-organizing properties of materials in confinement[2]; it allows a sub-micrometric control of the shape, size and positioning of the deposited structures. We fabricated patterned structures of graphene flakes on Si/SiOx (native) wafer. Subsequently the structures were exposed to an electrochemical process[3], resulting in the oxidation of the silicon located underneath the graphenic structures. By this process, we fabricated in-situ a metal/graphene/electrochemical SiOx/Si junction, which exhibited an efficient resistive switching with an on/off ratio in excess of 105. Remarkably, we observed that the presence of graphene flakes alters the mechanism of resistive switching compared to the same junction without graphene, changing from unipolar to bipolar[3]. Figure 1 shows a schematic diagram of the process and a AFM image of patterned electrochemical-SiOx fabricated by LCW combined with local oxidation.

Fig. 1 Left: a) Scheme of lithographically controlled wetting and b) local oxidation. Right, topographic image of electrochemically fabricated SiOx (x<2).

This work was supported by the EURY-ESF project DYMOT. References

[1] M. Cavallini, D. Gentili, P. Greco, F. Valle, F. Biscarini, Nat. Protoc. 7, 1668 (2012). [2] D. Gentili, F. Valle, C. Albonetti, F. Liscio, M. Cavallini Acc. Chem. Res. 47, 2692 (2014). [3] M. Cavallini, Z. Hemmatian, A. Riminucci, M. Prezioso, V. Morandi and M. Murgia, Adv. Mater. 24, 1197 (2012).

Book of Abstract

Polymer-based BP nanocomposites: preparation, characterization and properties

F. Cicogna1*, S. Coiai1, F. Costantino1, S. Legnaioli1, G. Lorenzetti1, M.Serrano-Ruiz2, M. Peruzzini2, E. Passaglia1

1Istituto di Chimica dei Composti Organo Metallici (ICCOM), Consiglio Nazionale delle Ricerche, SS Pisa, Via G. Moruzzi 1, 56124 Pisa, Italy

2Istituto di Chimica dei Composti Organo Metallici (ICCOM), Consiglio Nazionale delle Ricerche, Via Madonna del Piano 10, 50019 Sesto Fiorentino (FI), Italy

e-mail: francesca.cicogna@pi.iccom.cnr.it

Phosphorene, the few layers material obtained by of black phosphorus (BP), possesses many intriguing properties for example it is a semiconductor with thickness-dependent band gap, it shows prominent electron transport capability and low thermal conductance and it has a really good thermal resistance. However it is reported that in the applications it can undergo to severe degradation by moisture and oxygen upon prolonged air exposition. The formation of surface oxidized species is responsible for a measurable increase in surface roughness and degradation, with severe detriment of performances of phosphorene-based electronic devices that are prepared and measured in air [1]. In this work the preparation of polymer-based phosphorene nanocomposites where black phosphorus (BP) nanoflakes are embedded in the polymer matrix is described. In particular two methods were used: a solvent blending procedure [2] and the in situ polymerization technique of vinyl monomers starting from BP. Polystyrene, polymethylmetacrylate and poly(lactic acid) were used as polymer matrix whereas methylmethacrylate, 1-vinyl-2-pyrrolidone and styrene were used as monomers. FT-IR and Raman spectroscopies were employed to confirm the presence of both polymer matrix and filler whose aggregates dimension was tested by DLS, while the SEC measurements evidenced some effects of the preparation methodology onto the structural features of the matrices. TGA, DSC analysis as well as thermal oxidation techniques were employed to investigate the thermal stability of selected samples, evidencing really interesting polymer-nanofiller synergic effects. In particular, the BP nanoflakes, once incorporated in the polymer, showed an apparent improved stability even when the composites were stored in air, at room temperature in ambient conditions. These results widen the application possibilities of BP 2D nanoflakes once polymer-coated, suggesting the possibility of the direct use of the prepared nanocomposites in designing electronic devices. This work was supported by the European Research Council (ERC) under the European Unions Horizon 2020 research and innovation program (Grant Agreement No. 670173) in the frame of the project PHOSFUN “Phosphorene functionalization: a new platform for advanced multifunctional materials”through an ERC Advanced Grant. References

[1] S. P. Koenig, R. A. Doganov, H. Schmidt, A. H. Castro Neto, B. Özyilmaz, Appl. Phys. Lett. 104, 103106 (2014). [2] E. Passaglia, F. Cicogna, G. Lorenzetti, S. Legnaioli, M. Caporali, M. Serrano-Ruiz, A. Ienco, M. Peruzzini, RSC Adv. 6, 53777 (2016).

Book of Abstract

Structural characterization of 2D X-ene sheets by X-ray Absorption Spectroscopy (XAS).

F. d’Acapito1, S. Torrengo1, E. Xenogiannopoulou2, P. Tsipas2, J. Marquez Velasco2,3, D.

Tsoutsou2 and A. Dimoulas

2 1CNR-IOM-OGG c/o ESRF, LISA CRG, Grenoble France;

2Institute of Nanoscience and Nanotechnology,- DEMOKRITOS, Athens, Greece;

3Phys. Dept, National Technical University of Athens, Athens, Greece.

2-Dimensional IV semiconductors (X-enes), have recently received considerable attention, for their peculiar transport properties. Most of the work done so far has been on metal surfaces: 2D lattices of Ge have been observed on various metallic substrates but, as they are poorly compatible with silicon technology, efforts are devoted for obtaining 2D layers on more appropriate substrates. 2D graphite-like hexagonal AlN (h-AlN), a metastable phase favored at small thickness against the most known bulk wurtzite-AlN phase, is a promising insulating substrate for germanene growth. In this work, we present evidence of germanene formation 2D h-AlN insulating layers on Ag(111). By combining a number of experimental techniques such as RHEED, STM and UPS we first report the successful epitaxial growth of sp2-hybridized h-AlN layers on Ag(111) with a flat geometry by plasma assisted MBE. Subsequently, Ge layers were also deposited by MBE on an h-AlN buffer layer and were structurally characterized by RHEED, XAS and DFT calculations. RHEED data indicate a faint 4x4 superstructure with respect to (1x1) Ag(111), or a (3x3) reconstruction with respect to (1x1) germanene. XAS revealed to be particularly effective in these studies due to the possibility of precisely measure the Ge-Ge distance that depends strongly on the hybridization scheme. In this way ot could be possible to provide evidence of 2D Ge layer formation with an interatomic distance of dGe-Ge=2.38 Å, characteristic of free-standing germanene, also compatible with first-principles DFT calculations performed on the Ge/h-AlN/Ag(111) system with a buckling of 0.7 Å [1].

A similar XAS study has been conducted at the Sn-K edge on Sn layers deposited on AlN, Ge(111) and Bi2Te3. Preliminary RHEED investigations revealed the formation of Sn layers over the studied substrates. However, the XAS investigation has revealed formation of white tin (typical Sn-Sn distance ~3.00 Å) but in the case of Sn layer grown over Bi2Te3 an additional contribution of a Sn-Sn bond at 2.74(5) Å was revealed. This value is close to the distance theoretically calculated for free standing stanene (2.77 Å) and lower than the value for grey tin (2.81 Å) so this observation represents a strong indication of the formation of a 2D stanene layer over Bi2Te3.

References

[1] d’Acapito, S Torrengo, E Xenogiannopoulou, P Tsipas, J Marquez Velasco, D Tsoutsou and A Dimoulas J. Phys.: Condens. Matter 28 (2016) 045002.

Book of Abstract

Perspectives of 2D materials in gas sensing applications

L. Ottaviano2, S. M. Emamjomeh1, V. Paolucci1, F. Perrozzi2, C. Cantalini1

1Department of industrial Engineering – University of L’Aquila 2Department of Physical and Chemical Sciences & CNR-SPIN – University of L’Aquila

e-mail: carlo.cantalini@univaq.it

Two-dimensional (2D) materials like graphene oxide, phosphorene and more recently transition metal dichalcogenides (TMDs) have attracted tremendous interest for gas sensing applications considering their high surface to volume ratio, wide range of chemical compositions and their unique thickness-dependent physical and chemical properties. In this paper we report the gas sensing response of various 2D materials (Black Phosphorous (BP) [1], Graphene Oxide GO [2-3], chemically exfoliated MoS2 [4] and WS2 [5] Transition Metal Dichalchogenides (TMDs). Gas responses where investigated to oxidizing (NO2) and reducing gases (H2, NH3), demonstrating low detection limits of 1ppm H2, 1 ppm NH3 and 20ppb NO2 in dry air carrier, among the smallest so far ever reported for 2D materials. Depending on the 2D material the sonication process has been carried out either in air (GO, TMDs) or nitrogen (BP). All the chemically-exfoliated 2Ds have been drop casted on Si3N4 substrates provided with Pt comb-type interdigitated electrodes. The exfoliated 2Ds have been characterized by SEM, XPS, RAMAN, HRTEM, and STEM techniques to determine the microstructural properties related to the preparation conditions and the electrical response.

Fig. 1 TEM (a), AFM (b), Thickness Profile (c) and HRTEM (d) of chemically exfoliated WS2

Remarkable limitations, in terms of poor recovery of the base line and adsorption induced phenomena due to incomplete desorption of the gas molecules, have been recorded for all the investigated 2D materials, when operating at room temperature. By heating the sensors in the operating temperatures (OT) range 100°-150°C, full recovery and satisfactory reproducibility of the responses where achieved. To confirm long term stability of the electrical responses up to 150°C OT, thermal stability of all the prepared has been investigated and presented. The gas sensing response is discussed on the basis of a thorough study of the morphological and chemical properties of the 2D materials used.

References

[1] M. Donarelli et al., 2D Materials 3, 025002, (2016) [2] S. Prezioso et al., J. Phys Chem. C 117, 10683 (2013) [3] M. Donarelli et al., 2D Materials 2, 035018, (2015) [4] M. Donarelli et al., Sensors and Actuators B, 207, 602 (2015) [5] F. Perrozzi et al., Sensors and Actuators B, 243, 812 (2017)

(a)

Book of Abstract

The Sb-ene/Bi2Se3 interface: a route to investigating the proximity effect?

R. Flammini1 *, S. Colonna1, C. Hogan1, S. Mahatha2 , M. Papagno3, P. Sheverdyaeva2, A. Barla2 , P. Moras2 , Z. S. Aliev4, E. V. Chulkov5, F. Ronci1

1 CNR-ISM, Istituto di Struttura della Materia, Roma, Italy

2 CNR-ISM, Istituto di Struttura della Materia, Trieste, Italy 3 Dipartimento di Fisica, Università della Calabria, Arcavacata di Rende, Cosenza

4 Institute Catalysis and Inorganic Chemistry, Azerbaijan National Academy of Science, Baku, Azerbaijan 5 Donostia International Physics Center (DIPC), San Sebastián/Donostia, Basque Country, Spain

e-mail: roberto.flammini@cnr.it

The interface between a 2D system and a 3D topological insulator is drawing interest in view of potential applications related to the exploitation of the proximity effect. The expression “proximity effect” encloses a series of phenomena occurring at the interface between a trivial insulator and a topological insulator. When a heterostructure is indeed built the properties of both the trivial and the topological insulator can undergo stunning changes.[1,2] Here, we report recent results on the morphology and growth mode of antimony deposited on the surface of a prototypical topological insulator such as Bi2Se3. Indeed, antimony few layers are predicted to show the behaviour of trivial semiconductor [3]. STM measurements performed at room temperature show the formation of flat islands whose height is compatible with a double layer of buckled antimonene in the β-phase [4]. Upon completion, a second double layer starts to form. Moreover, atomic resolution images recorded at the boundary between bismuth selenide and antimonene show a well ordered structure and a perfect match between the two lattices, opening the possibility to exploit the antimony double layer as the suitable system to investigate its predicted peculiar electronic band structure [3] in presence of the topological surface states of the Bi2Se3. [5]

References

[1] F. Katmis et al., Nature 533, 513 (2016); [2] Li Xiao-Guang et al. Chin. Phys. B Vol. 22, No. 9, 097306 (2013) [3] P. Zhang et al. PRB 85 201410 (2012) [4] J. Ji et al, Nat. Commun. 7, 13352 (2016) [5] H. Zhang et al. Nat. Physics 5, 438 (2009)

Book of Abstract

STM studies of exfoliated black Phosphorus

A. Kumar1, F. Telesio1, A. Al Temimy2, S. Forti2, C. Coletti2, M. Serrano-Ruiz3, M. Caporali3, M. Peruzzini3, F. Beltram1,2, S. Heun1

1NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, 56127 Pisa, Italy 2Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, 56127 Pisa, Italy

3CNR-ICCOM, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy e-mail: abhishek.kumar@sns.it

After its exfoliation in 2014, black Phosphorus (bP) has emerged as a very interesting material in the category of two-dimensional (2D) materials, due to its properties like layer number-driven band gap tunability and in-plane anisotropy. Until now, scanning tunneling microscopy (STM) studies on this material have been performed only on bulk bP cleaved in-situ [1-3]. A study of thin flakes is more relevant for 2D applications, but it has been limited by the difficulty in preparation of such samples due to their high surface reactivity. We have exfoliated bP on epitaxial monolayer graphene on SiC in a Nitrogen atmosphere in a glove bag which facilitates inert environment for preservation of high sample quality. This is evident by the atomic resolution imaging achieved at room temperature, shown in Fig. 1. We have performed annealing experiments in which we have observed decreasing flake size with increasing temperature. Also the surface quality changes with temperature: the surface roughness increases by an order of magnitude after annealing at 450°C for 2 hours. Upon further annealing at 600°C, almost all flakes desorb from the surface.

Fig. 1. Left: Phosphorus atom arrangement in a bP monolayer; Right: STM atomic resolution image of the surface of an exfoliated bP flake (zig-zag atomic chain is indicated in blue). After this initial study, we are now investigating the surface morphological changes with temperature. We have already observed the formation of eye shaped craters on the surface due to atomic desorption after annealing at 375°C, close to the reported value [4,5]. We are further studying the alignment of these craters with respect to the crystallographic direction. These preliminary results will also be presented. This work was supported by an ERC Advanced Grant “Phosfun” (Grant Agreement No. 670173), a CNR Nano SEED project 2017, and Scuola Normale Superiore, project SNS16_B_HEUN – 004155. References

[1] L. Liang et al., Nano Lett., 14, 6400 (2014). [2] S.-L. Yau et al., Chem. Phys. Lett., 198, 383 (1992). [3] C. D. Zhang et al., J. Phys. Chem. C, 113, 18823 (2009). [4] X. Liu et al., J. Phys. Chem. Lett., 6, 773 (2015). [5] M. Fortin-Deschenes et al., J. Phys. Chem. Lett., 7, 1667 (2016).

Book of Abstract

The route to X-enes transistors: from silicene to phosphorene

C. Grazianetti1, L. Tao2, D. Akinwande2, A. Molle1 1Laboratorio MDM, IMM-CNR, via C. Olivetti 2, Agrate Brianza, I-20864, Italy

2Microelectronics Research Center, The University of Texas at Austin, TX-78758, U.S.A. e-mail: carlo.grazianetti@mdm.imm.cnr.it

The discovery of the X-enes family, namely the two-dimensional lattices beyond graphene (where X = Si, Ge, Sn, P…), might pave the way to a new flourishing era for condensed matter and applied physics [1]. Among them, the forerunner silicene on Ag(111) represents a paradigmatic example of a polymorphic X-ene lattice which has quickly trodden the route from the synthesis [1] up to the integration into operating devices either in its single [2] or multilayer [3] fashion. The main challenge in this sense relies on the strong interaction with its hosting metallic substrate, thus limiting the easy exploitation of silicene for functional applications, and claims for a specific handling process enabling the integration of silicene into a device platform. An overview of the state-of-the-art on the silicene transistors fabrication processes will be here given with emphasis on the role of portable substrates. To face the device integration issues, the delamination of single and multilayer silicene will be presented as a paradigmatic process for the fabrication of room temperature operating silicene transistors [2,3] that can be extended to other epitaxial X-enes. Indeed, the recent findings on the epitaxial phosphorene on Au(111) [4] represent a new challenge characterized by similar issues and thus might be a useful benchmark to test the versatility of the so-proposed methodology.

Fig. 1. Methodology for the X-enes integration into a transistor This work was supported by National Grant “CNR Joint Lab” for the project “Silicene Field Effect Transistors (SFET)” References

[1] C. Grazianetti et al., 2D Mater., 3, 012001 (2016). [2] L. Tao et al., Nature Nanotech., 10, 227 (2015). [3] C. Grazianetti et al., ACS Nano 11, 3376 (2017). [4] J. L. Zhang et al., Nano Lett., 16, 4903 (2016).

Book of Abstract

Electronic and structural properties of BP and MoS2 at high energy and spatial resolution

G. Nicotra1*, A. Politano2, F. Giannazzo1, Bongiorno1, M. Caporali3, I. Deretsis1, G. Fisichella1, A. La Magna1 , F. Roccaforte1, M. Peruzzini3, C.

Spinella1

1 CNR-IMM, Istituto per la Microelettronica e Microsistemi, Strada VIII, 5, 95121 Catania, Italy 2 Dipartimento di Fisica, Università della Calabria, via ponte Bucci, cubo 31/C 87036 Rende (CS) Italy

3 CNR-ICCOM, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy. e-mail: giuseppe.nicotra@imm.cnr.it

New nano composite 2D materials, such as Ni and Ru nanoparticles supported on the surface of few-layer black phosphorus (2D BP), have been studied through Atomic-resolution scanning transmission electron microscopy together with their electronic properties through energy-loss near-edge structure (ELNES). Excited states of black phosphorus relative to K and L absorption edges have been studied by energy-filtered transmission electron microscopy. The comparison of the calculated symmetry-projected density of unoccupied states and electron energy loss spectra allowed us to assign the spectral features to transitions to specific electronic states [2]. This is an important step in the assessment of their application capabilities. Among the new 2D materials, molybdenum disulfide (MoS2) is currently the object of high scientific and technological interest, as it represent a viable solution for post-Si complementary metal oxide semiconductor (CMOS) technology. One of the main challenges to exploit potentialities for the next generation CMOS technology is the realization of p-type or ambipolar field effect transistors (FETs). The morphological, and chemical modifications of MoS2 surface under different plasma conditions were investigated by several microscopic and spectroscopic characterization techniques, including aberration-corrected STEM/EELS [3]. All the experimental data have been acquired at high energy resolution with our GIF Quantum EELS spectrometer, installed on probe corrected JEOL ARM200F, combined with the simultaneous acquisition, in Dual EELS mode of low energy loss and high energy loss spectra acquired from the same regions in order to have a precise measurement on the edge onset [4]. These data have been then compared with ab- initio simulations, allowing us to clarify the role of O2 plasma induced modification of the MoS2 topmost layers on the observed p-type behaviour of the MoS2 transistors.

References

[1] M. Caporali, G. Nicotra et. al. under revision to Angewandte Chemie [2] G. Nicotra, et al, Phys. Status Solidi B, 253 2509 (2016) doi:10.1002/pssb.201600437 [3] F Giannazzo, G. Nicotra et al., submitted to Adv. Funct. Mater. [4] F. Fabbri, G. Nicotra et al., Nat Commun. 7 13044 (2016).

Book of Abstract

Key enabling processes for novel high frequency devices based on 2D materials integration with Nitride semiconductors

G. Greco1*, G. Fisichella1, E. Schilirò1, R. Lo Nigro1, I. Deretzis1, A. La Magna1, G. Nicotra1, C. Spinella1, M. Leszczyński2, A. Michon3, Y. Cordier3, S. Ravesi4, F. Roccaforte1, F.

Giannazzo1 1CNR-IMM, Strada VIII, 5, Zona Industriale, 95121 Catania, Italy

2TopGaN, Prymasa TysiÄclecia 98 01-424 Warsaw, Poland 3CNRS-CRHEA, Rue Bernard Gregory, 06560 Valbonne, France

4STMicroelectronics, Stradale Primosole 50, 95121 Catania, Italy e-mail: giuseppe.greco@imm.cnr.it

III-Nitrides semiconductors (such as GaN, AlN, InN and their alloys) are excellent materials for optoelectronics and high-power/high-frequency electronics. Recently, novel device concepts have been proposed by the integration of 2D materials (such as graphene (Gr) and transition metal dichalcogenides) with Nitrides. As an example, Gr/AlGaN/GaN heterostructures have been proposed to implement a Gr-Base Hot Electron Transistor (GBHET), i.e., a vertical device for ultra-high frequency (THz) applications, where Gr plays the role of the ultrathin base and the AlGaN/GaN 2DEG of the emitter [1]. However, the key enabling processes for devices fabrication need to be further investigated in order to achieve the targeted performances.

In this work, relevant key processes for the fabrication of the GBHETs have been developed and characterized, such as Ohmic contacts formation on Gr and AlGaN/GaN 2DEGs [2], and the atomic layer deposition (ALD) of ultra-thin dielectrics with high structural/electrical quality on Gr [3]. Two approaches for fabricating Gr/III-N heterostructures have been explored: (i) the transfer of Gr grown by CVD on catalytic metals (Cu) [4]; (ii) the direct CVD growth of Gr on AlN and AlGaN/GaN templates on different substrates (Si, SiC, sapphire), as well as on bulk AlN [1]. Electrical measurements on properly fabricated test patterns and local electrical analyses by CAFM [1,4] allowed to study the properties of contacts and dielectrics, as well as the vertical current transport across the Gr/III-N heterostructures. In addition, several structural, morphological characterization techniques were combined to investigate these heterostructures, e.g, XRD, STEM/EELS, XPS, LEED, Raman and AFM. The experimental information were compared with ab-initio DFT calculations of the Gr/III-N electronic properties.

All these results represent important advances towards the assessment of a Gr/Nitrides hybrid technology for next generation high frequency electronics.

This work has been supported by the FlagERA project “GraNitE: Graphene heterostructures with Nitrides for High-Frequency Electronics” (grant no. 0001411).

References

[1] F. Giannazzo, G. Fisichella, G. Greco, A. La Magna, F. Roccaforte, B. Pecz, R. Yakimova, R. Dagher, A. Michon, Y. Cordier, Phys. Status Solidi A (2016) DOI 10.1002/pssa.201600460. [2] G. Greco, F. Iucolano, F. Roccaforte, Appl. Surf. Sci. 383, 324-345 (2016). [3] G. Fisichella, E. Schilirò, S. Di Franco, P. Fiorenza, R. Lo Nigro, F. Roccaforte, S. Ravesi, F. Giannazzo, ACS Applied Materials & Interfaces 9, 7761-7771 (2017). [4] G. Fisichella, G. Greco, F. Roccaforte, F. Giannazzo, Nanoscale, 6, 8671

Book of Abstract

How to Decorate Phosphorene with Metal Fragments

A. Ienco1, G. Manca1, C. Mealli1, M. Peruzzini1 1CNR-ICCOM, Via Madonna del Piano 10, 50019 Sesto Fiorentino

e-mail: andrea.ienco@cnr.it

Availability of a lone pair for each phosphorus atom in phosphorene may allow in principle a easily functionalization of the surface. As in case of graphene [1], immobilization of transition metal fragments on the phosphorene surface may provide new electronic properties to the overall material. In this regards, computational chemistry offers useful hints to set up the most efficient synthetic strategy for the development of functionalized surfaces and predict electronic properties for future applications. Here we will present our computational screening of the most suitable metal fragments for phosphorene functionalization. Using the isolobal analogy, we have tested the possible h1, h2 and h3 coordination modes.

Figure 1. Phosphorene decorated Pt(Me)2 (left) and Mo(CO)3 (right) fragments

Finally, we compared the metal phosphorus bond strength in metal decorated phosphorene with the bond strength of classic metal phosphine such as triphenyl phosphine and white phosphorus. This work was supported by European Research Council through the ERC advanced project PHOSFUN “Phosphorene functionalization: a new platform for advanced multifunctional materials” (Grant Agreement No. 670173). References

[1] S. Sarkar, S. Niyogi, E. Bekyarova, R.C. Haddon, Chem. Sci. 2, 1326-1333 (2011)

Book of Abstract

High-pressure structure and reactivity of Phosphorus allotropes

D. Scelta1,2, M. Ceppatelli1,2, A. Baldassarre3, K. Dziubek1,4, R. Bini1,2,3 and M. Peruzzini2 1LENS, European Laboratory for Non-linear Spectroscopy, Via N. Carrara 1, I-50019 Sesto F.no, Firenze,

Italy 2ICCOM-CNR, Institute of Chemistry of OrganoMetallic Compounds, National Research Council of Italy,

Via Madonna del Piano 10, I-50019 Sesto F.no, Firenze, Italy 3Dipartimento di Chimica “Ugo Schiff” dell’Università degli Studi di Firenze, Via della Lastruccia 3,

I-50019 Sesto F.no, Firenze, Italy 4Faculty of Chemistry, Adam Mickiewicz University, Umultowska 89b, 61-614 Poznań, Poland

e-mail: scelta@lens.unifi.it

Pressure is extremely effective in reducing the molar volume of molecular samples, thus decreasing the intermolecular distances and forcing the intermolecular interactions. Combining high-density conditions, generated by pressure, with temperature and electronic photo-excitation, unexpected products can be obtained in absence of solvents and catalysts [1]. High-pressure (HP) studies of the structural and reactive behaviour of crystalline layered black Phosphorus (bP), made by the stacking of Phosphorene layers, could open new perspectives on both the possibility of pressure induced insertion of small systems between the 2D layers (as recently demonstrated in other nanostructured systems with comparable nanosized cavities [2,3]) and on the HP functionalization of the single Phosphorene layers. Following our experience with water [4] and alcohols [5], we have thus compared the HP, photo-induced reactivity of layered bP and amorphous red Phosphorus (rP) in the presence of NH3, to study the formation of new P-N functionalities. We have also related the different reactivity of bP and rP to their structural features. In the perspective of HP inclusion of simple systems between the layers, we have studied the structural behaviour of bP in the presence of small atoms and molecules (He, H2, N2, CO) and larger, non-penetrating silicon oil. We obtained unprecedented quality Equations of State (EOS) for bP and intriguing informations regarding the actual mechanism of the room T phase transition between rhombohedral (A7) and simple cubic (sc) bP at about 11 GPa.

This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 670173). References

[1] M. I. Eremets, A. G. Gavriliuk, I. A. Trojan, D. A. Dzivenko, and R. Boehler, Nat. Mater., 3, 558 (2004); M. Santoro, F. A. Gorelli, R. Bini, G. Ruocco, S. Scandolo, and W. A.Crichton, Nature, 441, 857 (2006); T. C. Fitzgibbons, M. Guthrie, E.-s. Xu, V. H. Crespi, S. K. Davidowski, G. D. Cody, N. Alem and J. V. Badding, Nat. Mater., 14, 43 (2015). [2] D. Scelta, M. Ceppatelli, M. Santoro, R. Bini, F. A. Gorelli, A. Perucchi, M. Mezouar, A. van der Lee, J. Haines, Chem. Mater., 26, 2249 (2014). [3] M. Ceppatelli, D. Scelta, G. Tuci, G. Giambastiani, M. Hanfland, R. Bini, Carbon, 93, 484 (2015). [4] M. Ceppatelli, R. Bini, M. Caporali, and M. Peruzzini, Angew. Chem. Int. Ed., 52 (8), 2313 (2013). [5] M. Ceppatelli, S. Fanetti, and R. Bini, J. Phys. Chem. C, 117 (25), 13129 (2013).

Book of Abstract

Unravelling Surface Basicity and Bulk Morphology of 2D Carbon-based Catalysts with Unique Dehydrogenation Performance

G. Tuci1, A. Rossin1, L. Luconi1, C. Pham-Huu2, R. Palkovits3 and G. Giambastiani1,*

1Institute of Chemistry of OrganoMetallic Compounds, ICCOM-CNR, Florence, 50019, Italy.

2Institut de Chimie et Procédés pour l’Energie, l’Environnement et la Santé, CNRS Strasbourg, France. 3Institut für Technische und Makromolekulare Chemie, RWTH Aachen University, Germany.

e-mail: giuliano.giambastiani@iccom.cnr.it

Activity and selectivity are key features at the basis of an efficient catalytic system for promoting one of the most important industrial processes at the heart of polymer synthesis: the steam- and oxygen-free dehydrogenation (DDH) of ethylbenzene (EB) to styrene (ST). The current industrial technology for ST production is a highly energy-demanding process that uses a large amount of steam and it is typically promoted by a K-Fe2O3 catalyst (K-Fe) at temperatures between 580 and 630 °C. Despite the general process feasibility, K-Fe lists the classical disadvantages of metal-based heterogeneous catalysts: a drastic deactivation/passivation due to the rapid generation of “coke” deposits and metal leaching or structural collapse occurring under harsh operative conditions. Carbon-based catalysts have emerged as valuable metal-free catalysts for DDH, offering superior performance in terms of activity and selectivity compared to the K-Fe system.[1] However, from the viewpoint of developing effective and sustainable metal-free catalysts for the DDH process, some key issues related to the complex puzzle of physicochemical and morphological properties of carbon nanomaterials still remain to be addressed.[2] In particular, the role of the surface basicity in N-doped carbons on the DDH selectivity and catalyst stability on stream, remains a matter of debate among the scientific community. This contribution sheds light on the complex structure-reactivity

relationships of a class of highly microporous, N-rich Covalent Triazine Frameworks (nearby 2D structure) with superior activity and stability in DDH compared to benchmark metal-based and metal-free systems of the state-of-the-art, particularly under harsh operative conditions close to those used in industrial plants (Fig. 1).[3]

References

[1] J. Zhang, D. S. Su, R. Schlögl, R. Wang, et al., Angew. Chem. Int. Ed., 49, 8640, (2010). [2] H. Ba, G. Tuci, G. Giambastiani, C. Pham-Huu, ACS Catal., 6, 1408, (2016). [3] G. Tuci, Rossin, L. Luconi, C. Pham-Huu, R. Palkovits, G. Giambastiani, Adv. Funct. Mater. DOI: 10.1002/adfm.201605672, (2017).

Fig. 1. A vs. A’ DDH of EB with CTF-ph (red curves) and K-Fe (green curves) catalysts at increasing reactor temperature: cat. 300 mg; 2.8 vol.% of EB in He at 30 mL min-1; temperature range: from 550 to 600°C.

Book of Abstract

Surface-confined polymerization as emerging technology for electronic devices

M. Di Giovannantonio1, M. Tomellini2, J. Lipton-Duffin3, G. Galeotti4, M. Ebrahimi4, A. Cossaro5, A. Verdini5, N. Kharche6, V. Meunier6, G. Vasseur7, Y. Fagot-Revurat7, D. F.

Perepichka8, F. Rosei4,9, and G. Contini1,10

1Istituto di Struttura della Materia, CNR, Via Fosso del Cavaliere 100, 00133 Roma, Italy

2Department of Chemistry and 10Department of Physics, University of Rome “Tor Vergata”, Via della Ricerca Scientifica 1, 00133, Roma, Italy

3Institute for Future Environments, Queensland University of Technology (QUT), 2 George Street, Brisbane, Queensland 4001, Australia

4Centre Énergie, Matériaux et Télécommunications, Institut National de la Recherche Scientifique, 1650 Boulevard Lionel-Boulet, Varennes, Quebec J3X 1S2, Canada

5CNR-IOM, Laboratorio TASC, 34149 Trieste, Italy 6Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, 110 Eighth

Street, Troy, New York, 12180, United States 7Institut Jean Lamour, UMR 7198, Université de Lorraine/CNRS, B.P. 70239, Vandoeuvre-Les-Nancy F-

54506, France 8Department of Chemistry, McGill University, 801 Sherbrooke Street, West Montreal, Quebec H3A 0B8,

Canada 9Institute for Fundamental and Frontier Science, University of Electronic Science and Technology of China,

Chengdu 610054, PR China e-mail: giorgio.contini@cnr.it

Graphene-like two-dimensional organic materials can be grown and confined onto suitable surfaces depositing and activating selected molecules. In this respect, the surface-confined polymerization is a promising route to create one- and two-dimensional covalent π-conjugated structures. In this talk I will report on our studies on surface-confined polymerization by using Ullmann coupling reaction obtained by complementary spectroscopic measurements of electronic occupied and unoccupied states (by photoelectron spectroscopy (X-ray photoelectron spectroscopy (XPS), angle-resolved photoelectron spectroscopy (ARPES)) and near edge X-ray absorption fine structure (NEXAFS) spectroscopy, respectively), scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. These methodologies have allowed to pinpoint a signature of the polymerization reaction and have added new information on the role played by halogen atoms in the process [1]. By scanning tunneling spectroscopy (STS) the quantization of the molecular states as a function of oligomer length has been followed. ARPES reveals a quasi-1D valence band as well as a direct electronic gap [2]. We use fast-XPS in kinetic measurements and devise a kinetic model based on mean field rate equations, involving a transient state, also observed in the energy landscapes calculated by nudged elastic band (NEB) within DFT, which assumes the geometries of the organometallic and polymeric structures observed by STM. The kinetic model accounts for all the salient features observed in the experimental curves extracted from the fast-XPS measurements and enables an enhanced understanding of the polymerization process, which is found to follow a nucleation-and-growth behavior preceded by the formation of a transient state [3].

References

[1] M. Di Giovannantonio et al., ACS Nano, 7, 8190 (2013); ACS Nano, 8, 1969 (2014). [2] G. Vasseur et al., Nat. Commun., 7, Article n. 10235 (2016). [3] M. Di Giovannantonio et al., J. Am. Chem. Soc., 138, 16696 (2016).

Book of Abstract

Cellular behaviour on few layer black phosphorus for tissue engineering

M.G Raucci1, I. Fasolino1, M. Caporali2, M. Serrano Ruiz2, M. Peruzzini2, L. Ambrosio1. 1Institute of Polymers, Composites and Biomaterials – National Research Council (IPCB-CNR). Mostra

d'Oltremare Pad.20 - Viale J.F. Kennedy 54, 80125 - Naples, Italy. 2Institute of Chemistry of Organometallic Compounds (ICCOM-CNR). Via Madonna del Piano 10, 50019 -

Sesto Fiorentino, Italy. e-mail: mariagrazia.raucci@cnr.it

Black Phosphorous (BP) has recently attracted great attention due to its specific structure with corrugated planes of P atoms connected by weak van der Waals forces. By breaking down the weak interlayer interactions, bulk BP can be exfoliated into thin Phosphorene sheets (2D BP)[1]. Few pioneering studies have shown the potential of 2D BP in biomedical applications[2], however, its behaviour as a substrate for cell colonization and proliferation has not yet been demonstrated. In our study, the cytotoxicity of BP and 2D BP was evaluated and the effect of 2D BP as substrate on healthy and cancer cells was also investigated.

The biological results showed that BP and 2D BP at different concentrations (10-500 µg/ml) have not negative effects on cell viability of murine fibroblasts (L929) and human Mesenchymal Stem Cells (hMSC) at 24 and 48 hours of culture time. Moreover, biological investigations on healthy cells (human pre-osteoblasts HOB) demonstrated that 2D BP substrate improved cell attachment and proliferation, see Fig.1, with a better expression of early marker of osteogenic differentiation like Alkaline Phosphatase (ALP) than cells seeded on tissue culture plate (CTR HOB) at day14. Opposite effects were observed on cancer cells (human osteosarcoma cell line, Saos-2) with a reduction of cell proliferation and inhibition of ALP activity (Fig.1). These results demonstrated that 2D BP enhances the growth and osteogenic differentiation of pre-osteoblasts (HOB) and inhibits the proliferation of human osteosarcoma cells. This study suggests the possibility to use phosphorene as 2D substrate for tissue engineering applications.

This work was supported by an ERC Advanced Grant PHOSFUN "Phosphorene functionalization: a new platform for advanced multifunctional materials" (Grant Agreement No. 670173) and PNR-CNR Aging Program 2012-2018.

References

[1] M. Serrano-Ruiz, M. Caporali, A. Ienco, V. Piazza, S. Heun, M. Peruzzini, Adv. Mater. Interfaces, 3, 1500441 (2016). [2] L. Mei et al. Adv. Mat. 29(1), 1603276 (2017) and references therein.

Book of Abstract