Formation of Porous Titanium Film and Its Application to Counter Electrode for Dye-Sensitized Solar Cell

It is important to reduce the series resistance of a dye-sensitized solar cell (DSC) to improve its conversion efficiency. Here, a porous titanium (Ti)/dense Ti/aluminum (Al)/glass composite counter electrode for a DSC was fabricated. A porous and a dense Ti layer were deposited by a DC magnetron sputtering process. The dense Ti film was used as a protective layer against corrosion of the Al layer, which reduces the sheet resistance of the counter electrode. The solution treatment furthermore roughened the surface of the porous Ti layer. The composite counter electrode increased the fill factor and short-circuit current, resulting in the improvement of the conversion efficiency of the DSC. Our results indicate that it is important to introduce a porous material to the counter electrode of the DSC to improve the performance of the DSC and that the porous Ti film with rough surfaces is a promising material. (C) 2010 The Japan Society of Applied Physics