Enhancement of Photocurrent and Photovoltage of Dye-Sensitized Solar Cells with TiO2 Film Deposited on Indium Zinc Oxide Substrate

Abstract

The effects of using indium zinc oxide (IZO) as a conducting substrate in dye-sensitized TiO2 solar cells (DSC) on their photocurrent−voltage characteristics are studied. We have found that both short-circuit photocurrent (Jsc) and open-circuit voltage (Voc) of IZO-based cells are substantially improved by about 40% and 10%, respectively, when compared with those of cells based on fluoride-doped tin oxide (FTO). The Jsc increase is correlated to the improved contact between IZO and TiO2 and enriched conduction band electrons in the TiO2-on-IZO electrode, due to the blocking of surface states by the evaporated metallic components of the substrate. The combined effects of the negative shift of flat band potential and the reduction in recombination explain the Voc increase. Our experimental finding suggests that IZO-coated substrate makes more efficient DSC than a FTO-coated one.