Effect of Porous Counter Electrode with Highly Conductive Layer on Dye-Sensitized Solar Cells

A Pt/porous titanium (Ti)/dense Ti/aluminum (Al)/glass composite counter electrode for a dye-sensitized solar cell (DSC) was fabricated and characterized. The introduction of a highly conductive Al film drastically reduced the sheet resistance of the counter electrode to improve the short circuit current and fill factor of the DSC. Porous and dense Ti layers were deposited by the DC magnetron sputtering process. The dense Ti layer protected the Al film from dissolution in the electrolyte solution to stabilize the composite counter electrode. The porous Ti layer with a larger electrochemical active area at the electrolyte/counter electrode interface mainly improved the short circuit current of the DSC. The results indicate the importance of the introduction of porous materials with highly conductive films into the counter electrode of a DSC and the suitability of composite materials of Al and Ti for the counter electrode.