Reduced graphene oxide modified titania photoanodes for fabrication of the efficient dye-sensitized solar cell

In the present investigation, a novel photoanode material TiO2-reduced graphene oxide (rGO) nanocomposite has been prepared and coated by doctor blade technique for the fabrication of dye-sensitized solar cells. The reduction of graphene oxide to reduced graphene oxide and the crystallization of the material has been achieved by one step thermal annealing of photoanodes at 400 °C. The UV–Visible absorption and photoluminescence studies were confirming the following attributes that, the reduction in band gap energy and the existence of longer lifetime of charge carriers in TiO2-rGO nanocomposite photoanodes respectively. Fourier transform infra-red characterization was confirming the bonding between TiO2 and rGO. The X-ray diffraction pattern fortified the formation of anatase titania with reduced crystallite size due to the presence of graphene. The scanning electron microscopy images of TiO2-rGO nanocomposite photoanodes revealed the presence of spherical nanoparticles and agglomeration of graphene sheets in TiO2 matrix. In addition, Raman and transmission electron microscopy analysis ensured the interaction between TiO2 and graphene. The solar cell with TiO2-rGO nanocomposite photoanode has 6.61% efficiency which was 30% higher than that of the pristine TiO2 nanoparticles based device. The electrochemical impedance spectroscopy analysis proposed the reduction in charge transfer resistance which was achieved in the newly developed photoanode employed devices.