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.