Enhancement of the photocurrent generation in dye-sensitized solar cell based on electrospun TiO2 electrode by surface treatment

We investigated the dye-sensitized solar cell (DSSC) using TiO2 electrode electrospun directly onto the substrate from a mixture of titanium propoxide and poly(vinyl acetate) in dimethyl formamide (DMF). The electrospun electrode could be penetrated efficiently by a viscous polymer gel electrolyte because of porous structure. The energy conversion efficiency obtained from the DSSC with poly(vinylidenefluoride-co-hexafluoropropylene) (PVDF-HFP) gel electrolyte was over 90% of that obtained from liquid electrolyte. In order to improve the short-circuit photocurrent, we treated the electrospun TiO2 electrode with TiCl4 aqueous solution. The rutile crystal was grown epitaxially on anatase TiO2 fibers. An additional TiO2 layer increased the volume fraction of active materials resulting in an increase of sensitizer adsorption. The incident photon-to-current conversion efficiency (IPCE) of TiCl4-treated electrode was higher than the untreated. In particular, the contribution from TiO2 increases after the surface treatment due to an increase in packing density. The photocurrent of the DSSC with electrospun TiO2 electrode was enhanced more than 30% after TiCl4 treatment.