hybrids with graphene for optical limiting applications
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Hybrids with Graphene for
Optical Limiting Applications
Pramod Gopinath
Indian Institute of Space Science and TechnologyValiamala, Thiruvananthapuram 695 547
Annual Photonics Workshop – February 28, 2014
IIST…
Annual Photonics Workshop – February 28, 2014
● Graphene – an Introduction● Methods of Graphene
Preparation● Characterization of Graphene● Optical Limiting● Graphene● Graphene-C60 Hybrid● Polyaniline-Graphene Hybrid● ZnO-Graphene Hybrid● Conclusion
Outline of the talk
2010 Nobel Prize for Physics
for ground breaking experiments regarding the two dimensional material graphene
Konstantin Novoselov and Andre Geim Centre for Mesoscience and Nanotechnology and
School of Physics and Astronomy, University of Manchester
Annual Photonics Workshop – February 28, 2014
Annual Photonics Workshop – February 28, 2014
Fullerene 0 D
Nanotube 1 D
Graphite Sheet 3 D
A. K. Geim & K. S. Novoselov. The rise of graphene. Nature Materials Vol . 6 ,183-191 (2007)
Graphene Sheet (2 D monolayer of carbon atoms)
Annual Photonics Workshop – February 28, 2014
Properties of Graphene
Electronic Properties – High electron mobility (230,000 cm2/Vs)
Thermal Properties - Thermal Conductivity ( 3000 W/mK)
Mechanical Properties – Strength (130 GPa), Young’s modulus (~1.3 TPa)
Optical Properties – 2.3% absorption of visible light
Quantum Hall Effect – minimum Hall conductivity ~ 4 e2/h
Annual Photonics Workshop – February 28, 2014
Preparation of Graphene
Top down approach from Graphite
Micromechanical exfoliation Creation of colloidal suspensions
Bottom up approach from carbon precursors
CVD Organic synthesis Epitaxial growth on insulating substrates
Annual Photonics Workshop – February 28, 2014
Preparation of Graphene
Micromechanical exfoliation
Annual Photonics Workshop – February 28, 2014
Preparation of Graphene
Graphite flakes are combined with sodium cholate in aqueous solution
Green and Hersam, Nano Letters, 9, 4031 (2009)
Annual Photonics Workshop – February 28, 2014
Preparation of Graphene
Roll based production of graphene films on copper foil
Annual Photonics Workshop – February 28, 2014
Preparation of Graphene
From Carbon nano tubes
NATURE, Vol , 458, 16 , April (2009)
Annual Photonics Workshop – February 28, 2014
Preparation of Graphene
Oxidation (Hummers’method)
H2SO4/ KMnO4
H2SO4/KClO3
Or H2SO4/HNO3
………………. H2O
Ultrasonication (exfoliation)
Graphite Oxide
Graphene Oxidemonolayer or few layers
Fuctionalization (for better dispersion)
Chemical reduction to restore graphitic structures
Making composite with polymersMaking composite with polymers
Annual Photonics Workshop – February 28, 2014
Graphene - Characterization
Optical Microscopy
Image of Single, Double and Triple layer Graphene on Si with a 300 nm SiO2 over layer
Annual Photonics Workshop – February 28, 2014
Graphene - Characterization
Atomic Force Microscopy
Images of unreduced and chemically reduced graphene oxide nanosheets deposited from aqueous dispersions
Annual Photonics Workshop – February 28, 2014
Graphene - Characterization
Flourescence Quenching Microscopy
Image showing G-O single layer deposited on a SiO2 /Si wafer applying a 30 nm thick fluorescein/PVP layer
Annual Photonics Workshop – February 28, 2014
Graphene - Characterization
Transmission Electron Microscopy
Image of a single layer Graphene membrane
Step from a monolayer to a bilayer
Annual Photonics Workshop – February 28, 2014
Graphene - Characterization
Raman Spectroscopy
D – 1350 cm-1
G – 1580 cm-1
2D – 2700 cm-1
D band – presence of disorder in atomic arrangement or edge effect
G band – in plane vibration of sp2 carbon atoms
2D band – second order Raman scattering
Annual Photonics Workshop – February 28, 2014
Nonlinear Optical Materials
Saturable Absorbers
which give increased transmittance at high optical intensities or fluences, and are useful for pulse compression, Q-switching and mode-locking
Optical Limiters
Which give decreased transmittance, and are useful for pulse shaping, mode locking and for the protection of eyes and sensor focal-plane arrays
Progress in development of Optical limiters with large NLO responses in carbon-based materials like, graphitic systems, single-walled CNTs, small π-electron systems like fullerenes, porphyrins and phthalocyanines
Challenge: Development of materials that can be processed as stable solutions or liquid dispersions that can ultimately be formed into films for practical applications
Annual Photonics Workshop – February 28, 2014
Optical Limiting
Open aperture Z-scan technique
Sheik-Bahae, M., et al. IEEE J. of Quantum Electron., 26(4): 760-769 (1990).
Annual Photonics Workshop – February 28, 2014
Optical Limiting
dtezqzq
SzT t2
0,1ln0,11, 0
0 2
02
00 1)1()0,( zzLIRzq eff where
α is the linear absorption coefficientL is the thickness of the sample
-12 -8 -4 0 4 8 12
0.6
0.8
1.0T no
rm
z(mm)1.3x1011 1012 6x1012
0.6
0.8
1.0
T nor
m
Input intensity (W/m2)
Open aperture Z-scan plot Optical limiting plot
R. L. Sutherland, Handbook of Nonlinear Optics, second ed., Marcel Dekker, New York, 2003.
z0 is the Rayleigh length.R is the Fresnel reflectance of the sample surfaceLeff is given by ]1[ Le
Annual Photonics Workshop – February 28, 2014
Annual Photonics Workshop – February 28, 2014
Annual Photonics Workshop – February 28, 2014
Annual Photonics Workshop – February 28, 2014
Annual Photonics Workshop – February 28, 2014
Graphene – C60 Hybrid
Annual Photonics Workshop – February 28, 2014
Graphene-Polyaniline Hybrid
Alen HeegerA.J.MacDiarmidH.Shirakawa
2000 Nobel Prize
Annual Photonics Workshop – February 28, 2014
Synthesis of graphite oxide (GO)Low temperature modified Hummers method
CharacterizationPeak position (cm-
1)Assigned vibrations
1729 C=O stretching
1399 Carboxy C-O stretching
1186 Epoxy C-O-C stretching
1084 Alkoxy C-O stretching
1632 Unoxidized C=C stretching
>3000 O-H stretching
35
40
45
500 1000 1500 2000 2500 3000 3500
5
10
15
Graphite
10841186
1399 1729 GO
% A
bsor
banc
e
Wavenumber (cm-1)
1632
Polyaniline-Graphite oxide hybrid – In-situ polymerization of aniline in the presence of synthesized graphite oxide
Annual Photonics Workshop – February 28, 2014
2 nm
SEM image AFM imageTEM image
2 nm
Annual Photonics Workshop – February 28, 2014
Synthesis of polyaniline-graphite oxide hybrid
In-situ polymerization of aniline in presence of GO
Various compositions : PxGy, (x =proportion of aniline, y= proportion of GO)- P4G1, P2G1, P1G1, and P1G2
Annual Photonics Workshop – February 28, 2014
TEM image
SEM images
HRTEM image
500 nm
Polyaniline
5 µm
P1G2
AFM image
3.2 nm 1 nm
Annual Photonics Workshop – February 28, 2014
Sample
name
β cm
GW-1
Isat GW
cm-2
Polyaniline 5.8 2.5
GO 5.5 3.5
P4G1 8 1.5
P2G1 11 0.7
P1G1 13 0.6
P1G2 19 0.4
Nonlinear optical properties
Annual Photonics Workshop – February 28, 2014
Polyaniline-phenylene diamine functionalized reduced graphene oxide hybrids
Synthesis of phenylene diamine modified reduced graphene oxide (GONH2)
Annual Photonics Workshop – February 28, 2014
TEM imageSEM image
5 µm
Annual Photonics Workshop – February 28, 2014
Synthesis of polyaniline-phenylene diamine modified reduced graphene oxide hybrid
GONH2 to aniline ratio 1:21:12:1
Annual Photonics Workshop – February 28, 2014
TEM images
SEM image
Annual Photonics Workshop – February 28, 2014
Remyamol T, Pramod Gopinath, Honey John. Synthesis and nonlinear optical properties of reduced graphene oxide covalently functionalised with polyaniline. Carbon 59 (2013) 308-314.
Sample nameβ
cm GW-1
Isat
GW cm-2
Polyaniline 5.8 2.5
GONH2 4.8 3.7
P2NH2G1 12 0.6
P1NH2G1 15 0.5
P1NH2G2 25 0.2
Annual Photonics Workshop – February 28, 2014
Synthesis of polyaniline-reduced graphene oxide hybrid
Covalently grafted polyaniline- reduced graphene oxide hybrid
Annual Photonics Workshop – February 28, 2014
SEM image
TEM image
Annual Photonics Workshop – February 28, 2014
Open aperture Z-scan plots Optical limiting plots
Sample name β cm
GW-1
Isat GW
cm-2
GO 5.5 3.5
Polyaniline 9.5 2
Polyanilne-g-rGO 20 0.25
Remyamol T, Pramod Gopinath, Honey John. Grafting of self assembled polyaniline nanorods on reduced graphene oxide for nonlinear optical application. Synthetic Metals 185-186 (2013) 38-44.
Annual Photonics Workshop – February 28, 2014
Reduced Graphene oxide-ZnO Hybrid
Reduced graphene oxide –ZnO hybrid is synthesized by two routes:
Hydrothermal Synthesis
Solution precipitation technique
Annual Photonics Workshop – February 28, 2014
Reduced Graphene oxide-ZnO Hybrid
Zn(Ac)2 (1 mmol)
CH3COOHPolyvinylpyrrolidone
(PVP) (0.05 %)
Zn(Ac)2- PVP complex
NaOH
Kept in autoclave at different temperature for
7 h @ 100oC(hydrothermal method)
H-rGO-ZnO-x
Different weight ratios of GO Dispersed by sonication
for 8 h Followed by stirring for 16h
ZnO/GO colloid
Stirred at room temperature for 12 h
(solution precipitation)S-rGO-ZnO-x
Annual Photonics Workshop – February 28, 2014
Annual Photonics Workshop – February 28, 2014
Decrease of oxygen functional groups in hybrid in both the samples peak at 1730 cm-1 (C=O stretching vibrations of the –COOH groups) is absent For S-rGO-ZnO, peak at 1680 cm-1 indicate C=O in conjugation with C=C ID/IG ratios 0.94 and 1.03 for H-rGO-ZnO and S-rGO-ZnO Restacking of exfoliated graphene sheets are prevented by the as-grown ZnO nanoparticles
IR and Raman spectra of H-rGO-ZnO and S-rGO-ZnO
Annual Photonics Workshop – February 28, 2014
compared to bare ZnO and GO, hybrid shows enhanced nonlinear optical properties photoinduced electron transfer and energy transfer For hydrothermally synthesized hybrid, more extended -conjugation results in enhanced NLO properties
Annual Photonics Workshop – February 28, 2014
Lot of scope for further work in Hybrids as the optical limiting properties can be enhanced by suitably modifying the functionalities
Conclusion
Annual Photonics Workshop – February 28, 2014
Collaborators:
1. Dr. Honey John, Department of Chemistry, IIST2. Dr. Reji Philip, Raman Research Institute
Research Students:
1. Ms. Remyamol T2. Ms. Kavitha M K
A word of Gratitude……
Annual Photonics Workshop – February 28, 2014
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