Improved performance of dye-sensitized solar cells by trace amount Cr-doped TiO_2 photoelectrodes

摘要

Trace amount chromium-doped (Cr-doped) TiO_2 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 TiO_2 . Rutile phase increases when Cr is incorporated into TiO_2 while the property of electron transport in photoelectrodes is improved by doping Cr which results in a reduced resistance (R~(ct)) of the electron transport within mesoporous layer and an improved electron lifetime. The regularity of R_(ct) 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 (J_(sc) of DSSCs is remarkably enhanced and reaches maximum. Consequently, the overall energy conversion efficiency enhances to 6.35% with Cr-doped TiO_2 of 50 ppm, which is 14.62% higher than that with undoped TiO_2. In general, compared with undoped TiO_2, Cr-doped TiO_2 is a better photoanode material and a more promising alternative for high efficient DSSCs.