UV-reduction of graphene oxide and its application as an interfacial layer to reduce the back-transport reactions in dye-sensitized solar cells

A mixture of graphene oxide (GO) and TiO2 nanocomposites was reduced photocatalytically by UV-irradiation and applied as interfacial layer between a fluorine doped tin oxide (FTO) layer and a nanocrystalline TiO2 film. Impedance spectra implied a decreased back-transport reaction of electrons. The graphene–TiO2 interfacial layer effectively reduced the contact between I 3 - ions in the electrolyte and FTO layer, which inhibited back-transport reaction. The introduction of graphene–TiO2 increased Voc by 54 mV and the photoconversion efficiency was improved from 4.89% to 5.26%.