Few layers of graphene as transparent electrode from botanical derivative camphor

Here, we report synthesis of large area graphene sheets by control pyrolysis of solid botanical derivative camphor (C10H16O) and fabrication of transparent electrodes. Raman study shows highly ordered graphene sheet with minimum defects. Second order Raman spectrum shows that graphene layers are more than single layer and can be controlled with amount of camphor pyrolyzed. Transmission electron microscopic images show presence of 4 layers for thinner and 13 layers for thicker graphene sheets. Transferred graphene sheets on glass substrates show very good transparency in wide range of wavelength (0.3-2 mu m). Electrical measurements of the graphene sheets show thickness dependent sheet resistance. A sheet resistance of 203 Omega/sq is obtained at a transmittance of 63.5% of the graphene sheet. The technique to fabricate few layer of graphene as transparent electrode from camphor is both viable and scalable for potential large area optoelectronic applications. (C) 2010 Elsevier B.V. All rights reserved.