Electrospun TiO2 electrodes for dye-sensitized solar cells

Abstract

We report the new application of electrospun TiO 2 fibres as an electrode for dye-sensitized solar cells (DSSCs). TiO 2 fibre electrode was electrospun directly onto a conducting glass substrate from a mixture of titanium(IV) propoxide and poly(vinyl acetate) (PVAc) in dimethyl formamide. The TiO 2 fibres are composed of one-dimensionally aligned nanofibrils about 20 nm thick with an islands-in-a-sea morphology, which was obtained from the phase separation of TiO 2 gel and PVAc during the solidification process. The porous structure of the electrospun TiO 2 electrode was found to be efficiently penetrated by a viscous polymer gel electrolyte. In order to improve the photocurrent generation, we treated the electrospun TiO 2 electrode with TiCl 4 aqueous solution. The rutile crystal was grown on the surface of anatase TiO 2 fibres. An additional TiO 2 layer increased the volume fraction of active materials, resulting in an increase of sensitizer adsorption. The energy conversion efficiency obtained from electrospun TiO 2 electrodes with a PVDF-HFP gel electrolyte was over 90% of that from a liquid electrolyte system.