Improved performance of dye-sensitized solar cells by trace amount Cr-doped TiO2 photoelectrodes

Abstract

Trace amount chromium-doped (Cr-doped) TiO2 is prepared by hydrothermal method for dye-sensitized solar cells (DSSCs). The effect on photovoltaic performance of the cells is investigated via control of the concentrations of Cr doped in TiO2. Rutile phase increases when Cr is incorporated into TiO2 while the property of electron transport in photoelectrodes is improved by doping Cr which results in a reduced resistance (Rct) of the electron transport within mesoporous layer and an improved electron lifetime. The regularity of Rct and electron lifetime is reversed when the level of doped Cr exceeds 50 ppm. On the other hand, owing to the doping effect of Cr, the short-circuit photocurrent density (Jsc) of DSSCs is remarkably enhanced and reaches maximum. Consequently, the overall energy conversion efficiency enhances to 6.35% with Cr-doped TiO2 of 50 ppm, which is 14.62% higher than that with undoped TiO2. In general, compared with undoped TiO2, Cr-doped TiO2 is a better photoanode material and a more promising alternative for high efficient DSSCs.