Phosphotungstic acid and WO3 incorporated TiO2 thin films as novel photoanodes in dye-sensitized solar cells

Dye-sensitized solar cells (DSSCs) based on phosphotungstic acid–TiO 2 composites (PT) and WO 3 nanoparticle incorporated TiO 2 photoanodes were successfully constructed by doctor blading TiO 2 paste containing PT and various amounts of WO 3 . Film features were investigated by scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, transmission electron microscopy, and ultraviolet–visible spectroscopy. Photoelectrochemical properties were examined by the photocurrent–voltage ( J – V ) curves as well as monochromatic incident photon-to-photocurrent conversion efficiency and electrochemical impedance spectroscopy (EIS) measurements. Compared with the DSSC based on pure P25 films, that based on PT/P25 films yielded a 16.9% higher J sc and a 21.3% higher η , while that based on PT/P25   +   1/70WO 3 films resulted in a 49.2% higher J sc and a 40.3% higher η . EIS data demonstrated that charge transfer resistance was clearly reduced by introducing PT and WO 3 into TiO 2 films. The introduction of PT and WO 3 was observed to promote electron transfer and retard recombination synergistically, leading to a significant improvement in cell performance.