CHEMICAL SYNTHESIS OF GRAPHENE FOR DYE SOLAR CELLS ELECTRODES Presenter: F. T. Thema Name of presentation Organisation name Overview • Introduction • 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 m2 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 (106 times of copper) 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 Intensity a.u. GO r-GO (Anealing) r-GO (Our Method) 500 1000 1500 2000 Raman Shift cm Material ID/IG GO 1.2 r-GO (Annealing) 0.95 r-GO (Our Method) 0.96 2500 -1 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. I thank you !!!