Chemical synthesis of graphene for dye solar cells electrodes

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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.

I thank you !!!