TiO2 nanofibers resembling 'yellow bristle grass' in morphology by a soft chemical transformation

We synthesized a uniquely shaped one-dimensional (1-D) TiO2 nanostructure having the morphology of yellow bristle grass with high surface area by the titanate route under mild reaction conditions. The electrospun TiO2-SiO2 composite nanofibers upon treatment with concentrated NaOH at 80 degrees C under ambient pressure for 24 h resulted in sodium titanate (Na2Ti3O2) nanostructures. The Na2Ti3O7 nanostructures have an overall 1-D fibrous morphology but the highly porous fiber surfaces were decorated with layered thorn-like features (a morphology resembling that of yellow bristle grass) resulting in high surface area (113 m(2) g(-1)) and porosity. The Na2Ti3O7 nanostructures were converted into TiO2 nanostructures of the same morphology by acidification (0.1 N HCl) followed by low temperature sintering (110 degrees C) processes. Dye-sensitized solar cells (DSCs) constructed out of the material (cells of area 0.20 cm(2) and thickness 12 mu m) showed a power conversion efficiency (eta) of 8.02% in comparison with commercial P-25 TiO2 (eta = 6.1%).