Nanofibrous TiO₂ improving performance of mesoporous TiO₂ electrode in dye-sensitized solar cell

A method of direct coating of conducting glass by electrospinning was developed. Electrospun fibrous TiO₂ consisting of closely packed anatase nanocrystals of 40–50 nm in size was incorporated into mesoporous TiO₂ thin film stabilized by phosphorus. The mesoporous framework formed by walls with 5–6 nm TiO₂ nanocrystals surrounding 20 nm mesopores exhibits extreme porosity and consequently limited number of necking points. TiO₂ with fibrous morphology was found to solidify mesoporous titania and to be beneficial for the performance of corresponding photoanode in dye-sensitized solar cell (DSC). Obviously, its wire-like structure suitably interconnects mesoporous network and thus increases the electron collection efficiency from the TiO₂ layer to the F-doped SnO₂ electrode. The solar conversion efficiency of a DSC employing optimized photoanode consisting of nanocrystalline fibrous bottom layer, four mesoporous layers, and one nanocrystalline anatase scattering top layer sensitized with the N945 dye reached 5.35 %. This represents an improvement of about 9 % compared to the solar conversion efficiency of a DSC employing purely mesoporous TiO₂ layer prepared by means of phosphorus doping (5.05 %).