The photovoltaic performance of dye-sensitized solar cells enhanced by using Dawson-type heteropolyacid and heteropoly blue-TiO2 composite films as photoanode

Dawson-type heteropolyacid {P2Mo18VI} and its two-electron heteropoly blue {P2Mo2VMo16VI}-doped TiO2 composites have been successfully prepared by a simple sol–gel method and introduced into the photoanode of dye-sensitized solar cells (DSSCs), which results in a significant performance enhancement of DSSCs. The electrochemical impedance spectroscopy (EIS) and open-circuit voltage decay (OCVD) curve were employed to investigate the electron transport and carrier recombination behavior in DSSCs. The results show that doping with {P2Mo18VI} and {P2Mo2VMo16VI} could both suppress the dark current and increase the electron lifetime in DSSCs. The performance of DSSCs with both {P2Mo18VI}-doped and {P2Mo2VMo16VI}-doped photoanodes is better than that with pure P25 photoanodes and the overall conversion efficiency was improved by 24.48% and 17.19%, respectively.