Dye-sensitized solar cells fabricated with novel polymeric solid electrolyte films

The performance of dye-sensitized solar cells (DSSCs) was studied by examining properties of the polymeric solid electrolyte (PSE) such as ionic conductivity, melting point, etc. Electrochemical reactions taking place inside the DSSCs were also closely studied using electrical impedance spectroscopy. The following three findings were obtained: 1) the short-circuit current density (Jsc) of a DSSC decreases with the PVDF-HFP-based polymer content of the PSE, chiefly due to the decrease in the diffusion coefficient of I/sub 3//sup -/; 2) we confirmed that a PSE/Pt interface was established as well as the electrolyte solution/Pt interface; and 3) the polymer content should be as low as possible in order to achieve a higher Jsc. The trade-off for decreasing the polymer content is the diminishment of the PSE tensile strength at high temperatures because the melting point of the PSE drops. Taking both factors into account, the preferable polymer content was found to be between 25 and 30 mass%. In this polymer content range, the Jsc of a PSE-based DSSC is about 80% that of a solution-based DSSC.