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

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 TiO₂-reduced graphene oxide nanocomposite photoanode. X-ray diffraction analysis of TiO₂-reduced graphene oxide nanocomposites proved the anatase phase titania. Scanning electron microscope analysis confirmed the incorporation of reduced graphene oxide in TiO₂ matrix. Transmission electron microscopic analysis established the dispersion of reduced graphene oxide in TiO₂ network. The influence of reduced graphene oxide on the band gap and life-time of electron–hole pair in TiO₂-reduced graphene oxide nanocomposites was observed from ultra violet–visible and photoluminescence spectra respectively. Fourier transform infra-red analysis confirmed the expected interaction between TiO₂ and reduced graphene oxide. An increase in electrical conductivity was observed in TiO₂-redcued graphene oxide nanocomposites than the pristine TiO₂. The optimized TiO₂-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 TiO₂-redcued graphene oxide nanocomposite photo anode exhibited enhanced efficiency of 0.47–0.57%.