Graphene layer reduced back-transport reaction and increased power conversion efficiency of dye-sensitised solar cells

Abstract

Modified dye-sensitised solar cells were fabricated by inserting graphene layers between fluorine-doped tin oxide electrodes and mesoscopic titanium dioxide films. The results of current–voltage characterisation under dark condition and using electrochemical impedance spectroscopy indicate that the graphene layers can inhibit back-transport reaction of photogenerated electrons in dye-sensitised solar cells. Consequently, the photovoltaic performance of dye-sensitised solar cells markedly increased. The open-circuit voltage and fill factor show increments of 90 mV and 0·09, respectively. The power conversion efficiency improves from 4·51 to 5·42%.