Optimization of tandem-structured dye-sensitized solar cell

We optimized tandem-structured dye-sensitized solar cells (T-DSSCs) that consist of a N719-sensitized UV–visible-responsive top cell and a black dye-sensitized near-infrared-responsive bottom cell. The relationship between the thickness (dT) of TiO2 film in the top cell and the performance of T-DSSC was examined both for parallel and series T-DSSCs. The optimized parallel T-DSSC gave the photovoltaic conversion efficiency (η) of 10.6% (aperture area; 0.188 cm2, and total area; 0.25 cm2) under solar-simulating light conditions (AM 1.5, 100 mW cm−2); this η value was certified as the highest value of the conversion efficiency for T-DSSCs.