Transcript Chemical synthesis of graphene for dye solar cells electrodes
CHEMICAL SYNTHESIS OF GRAPHENE FOR DYE SOLAR CELLS ELECTRODES Presenter: F. T. Thema
Name of presentation
Organisation name
• Introduction
Overview
• Aim and Objectives • Production of graphene • Graphene oxide film preparation • Morphological properties of GO • Spectroscopy of GO • Conclusion • Future work • Acknowledgements • References
Introduction
Graphene Superlatives
Thinnest imaginable material largest surface area (2.700 m 2 per gram) Strongest material ever measured (theoretical limit) Stiffness known material (stiffer than diamond) Most stretchable crystal (up to 20 % elasticity) Record thermal conductivity (outperforming diamond) Highest current density at room T (10 6 copper) times of Completely impermeable (even He atoms cannot squeeze through)
Aim and Objectives Aim:
• To use the unusual and unique properties of graphene as transparent and conductive electrode to be used as TCO equivalent.
Objectives:
• Use modified Hummer’s method to synthesize/engineer large graphene thin films with different properties (3-5 nm) • Use reduced graphene oxide in solar cells
Production of graphene
Methods of producing graphene
• K.S. Novoselov et al Nature 2012,
490, 192–200
K.S. Novoselov et al Nature
2012, 490, 192–200
Graphene Oxide Film Preparation
Graphite Flakes GO suspension in water
Morphological Properties of GO
e -
Conductive
Optical Microscopy Scanning Electron Microscopy
Raman characterization of GO and rGO
GO r-GO (Anealing) r-GO (Our Method) 500 Material GO r-GO (Annealing) r-GO (Our Method) 1000 1500 2000 Raman Shift cm -1 2500 I D /I G 1.2
0.95
0.96
3000
Conclusion
• Graphene oxide solution was produced • Vacuum filtration was used to produce large area graphene oxide films • The graphene oxide was reduced to produce graphene with suitable properties for use as a TCO
Future work
• Use different methods to reduce graphene oxide to graphene • Use the large area graphene films as transparent conductors in solar photovoltaic devices
Acknowledgements
• iThemba LABS • Unisa • Philip - iThemba LABS Radiobiology • Stephen Nzioki & B , Dr F. Cumings & B. Sone – UWC • Chris B – iThemba LABS • Takalani Madima - Unisa • G Bepete & N.J. Coville – WITS University
•
Related
publications
F.T. Thema et.al Synthesis and characterization of graphene thin films by chemical reduction exfoliated and intercalated graphite oxide. J. Chem. (2013) DOI: 10.1155/2013/150536.
• F.T. Thema et al Synthesis and characterization of graphene thin films via Hummers Method. Technical Proceedings of the Nano Science and Technology
Institute, (2012) 1, 13-16. ISBN 678-1-4665-6274-5.
• Ezekiel D. Dikio, Force T. Thema et. al One-step reduction, characterization and magnetic behaviour of exfoliated graphene oxide. J. Mater. Sci. Pol. (2012) DOI: 10.2478/s13536-012-0068-2.
• Abdullahi M. Farah, Force T. Thema et.al Electrochemical detection of hydrogen peroxide based on graphene oxide/Prussian blue modified glassy carbon electrode. Int. J. Electrochem. Sci. 7(6) (2012) 5069 – 5083.
• E.D. Dikio, F.T. Thema, et. al Synthesis of carbon nanotubes by catalytic decomposition of ethane using Co-Zn-Al catalyst. Inter. J. Nanotech Appl, vol 4, 2
(2010) 117-124.