Reduced graphene oxide embedded titanium dioxide nanocomposite as novel photoanode material in natural dye-sensitized solar cells

摘要

Dye-sensitized solar cells were fabricated using the natural dye anthocyanin extracted from Nerium oleander, Ixora coccinea and Erythrina variegata flowers with sol-gel routed TiO_2-reduced graphene oxide nanocomposite photoanode. X-ray diffraction analysis of TiO_2-reduced graphene oxide nanocomposites proved the anatase phase titania. Scanning electron microscope analysis confirmed the incorporation of reduced graphene oxide in TiO_2 matrix. Transmission electron microscopic analysis established the dispersion of reduced graphene oxide in TiO_2 network. The influence of reduced graphene oxide on the band gap and life-time of electron-hole pair in TiO_2-reduced graphene oxide nanocomposites was observed from ultra violet-visible and photoluminescence spectra respectively. Fourier transform infra-red analysis confirmed the expected interaction between TiO_2 and reduced graphene oxide. An increase in electrical conductivity was observed in TiO_2-redcued graphene oxide nanocomposites than the pristine TiO_2. The optimized TiO_2-redcued graphene oxide nanocomposite was used as an anode material in the construction of dye-sensitized solar cells and the performance was studied by photocurrent-voltage characteristics and electrochemical impedance spectroscopy. The solar cells with TiO_2-redcued graphene oxide nanocomposite photo anode exhibited enhanced efficiency of 0.47-0.57%.