Study of structural and optical properties of low temperature photo-activated ZnO-rGO composite thin film

Zinc oxide-reduced graphene oxide (ZnO-rGO) nanocomposite thin films were fabricated by dip-coating various substrates with a homogeneous dispersion of graphene oxide powder in a sol-gel derived ethanolic solution of zinc acetate and subsequent photo-annealing with deep-ultraviolet radiation. For comparison, ZnO thin films and ZnO-rGO thin films thermally annealed at 500 °C were also prepared. The low temperature deep-ultraviolet irradiation resulted in crystallization of ZnO and reduction of graphene oxide which was confirmed by x-ray diffraction and Raman spectroscopy. Moreover, the Raman spectra also revealed that the reduction degree of graphene oxide was highest for deep-ultraviolet irradiated ZnO-rGO thin film. These results show that photo-chemical activation by deep-ultraviolet irradiation provides a low temperature, environment friendly technique to make ZnO-rGO thin films and can be used to fabricate semiconductor-graphene composite thin films on flexible substrates.