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

• Phosphotungstic acid/WO3-incorporated TiO2 nanocomposite films were fabricated by doctor-blading method.
• DSSCs based on phosphotungstic acid WO3 nanoparticles incorporated TiO2 photoanodes were successfully constructed.
• Efficient charge transfer of phosphotungstic acid/WO3-incorporated TiO2 led to a significantly improvement in cell performances.
• Phosphotungstic acid/WO3-incorporated TiO2 provides a promising strategy to improve the efficiency oficiency of DSSCs.

Dye-sensitized solar cells (DSSCs) based on phosphotungstic acid–TiO2 composites (PT) and WO3 nanoparticle incorporated TiO2 photoanodes were successfully constructed by doctor blading TiO2 paste containing PT and various amounts of WO3. 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 Jsc and a 21.3% higher η, while that based on PT/P25 + 1/70WO3 films resulted in a 49.2% higher Jsc and a 40.3% higher η. EIS data demonstrated that charge transfer resistance was clearly reduced by introducing PT and WO3 into TiO2 films. The introduction of PT and WO3 was observed to promote electron transfer and retard recombination synergistically, leading to a significant improvement in cell performance.