Modification of a TiO2 photoanode by using Cr-doped TiO2 with an influence on the photovoltaic efficiency of a dye-sensitized solar cell

Abstract

This work reports on the preparation of Cr-doped TiO2 (Cr-TiO2) and its utilization in the photoanode of a dye-sensitized solar cell (DSSC). Pure TiO2 and 10% Cr-TiO2 sols were individually obtained via hydrolysis followed by a hydrothermal process at 250 °C for 12 h. The TiO2 sol was first coated on a fluorine-doped tin oxide (FTO) substrate using a polymer binder and sintered at 500 °C for 30 min. The Cr-TiO2 sol was then deposited on the TiO2 layer through the same procedure, thus forming two different layers on the substrate. We found that the photovoltaic efficiency was improved by ca. 18.3% when the double layer was adopted as the photoanode of a DSSC instead of only the TiO2 layer. We assume that this improvement was caused by the repression of electron recombination occurring in the double layer. Further characterizations were carried out to clarify the function of the double layer. © 2008 The Royal Society of Chemistry.