Electrospun TiO2 electrodes for dye-sensitized solar cells

Abstract

We report the new application of electrospunTiO2 fibres as an electrode for dye-sensitized solar cells (DSSCs).TiO2 fibre electrode was electrospun directly onto a conducting glass substrate from a mixture oftitanium(IV) propoxide and poly(vinyl acetate) (PVAc) in dimethyl formamide. TheTiO2 fibres are composed of one-dimensionally aligned nanofibrils about 20 nm thick with anislands-in-a-sea morphology, which was obtained from the phase separation ofTiO2 gel and PVAc during the solidification process. The porous structure of the electrospunTiO2 electrode was found to be efficiently penetrated by a viscous polymer gel electrolyte. Inorder to improve the photocurrent generation, we treated the electrospunTiO2 electrodewith TiCl4 aqueous solution. The rutile crystal was grown on the surface of anataseTiO2 fibres. Anadditional TiO2 layer increased the volume fraction of active materials, resulting in an increase ofsensitizer adsorption. The energy conversion efficiency obtained from electrospunTiO2 electrodes with a PVDF-HFP gel electrolyte was over 90% of that from a liquid electrolytesystem.