New application of electrospun TiO2 electrode to solid-state dye-sensitized solar cells

A new application of electrospun TiO2 nanofibers was reported for an electrode for dye-sensitized solar cells (DSSCs). TiO2 nanofiber electrode was electrospun directly onto a FTO substrate from a mixture of titanium propoxide and poly(vinyl acetate) (PVAc) in dimethyl formamide. The TiO2 nanofibers are composed of one-dimensionally aligned fibrils ca. 20-nm thick with an islands-in-a-sea morphology, which was obtained from the phase separation of TiO2 gel and PVAc during solidification process. The pretreatment of the electrospun web by exposing it to solvent vapor prior to calcination at 450 °C in air was found to result in a stable electrode that could be used in a DSSC. The electrospun TiO2 electrode could be efficiently penetrated by a viscous polymer gel electrolyte because of its porous structure. The DSSC with electrospun TiO2 electrode with gel electrolyte based on PVDF-HFP reveals the conversion efficiency of 3.8 % with the global AM 1.5 illumination of 100 mW/cm2. The overall conversion efficiency of gel electrolyte system was found to be over 90 % of liquid electrolyte.