Improved-Performance Dye-Sensitized Solar Cells Using Nb-Doped TiO_2 Electrodes: Efficient Electron Injection and Transfer

摘要

Well-crystallized Nb-doped anatase TiO_2 nanoparticles are prepared by a novel synthetic route and successfully used as the photoanode of dye-sensitized solar cells (DSSCs). The homogenous distribution of Nb in the TiO_2 lattice is confirmed by scanning transmission electron microscopy (STEM) elemental mapping and line-scanning analyses. After Nb doping, the conductivity of the TiO_2 powder increases, and its flat-band potential (V_(fb)) has a positive shift. The energy-conversion efficiency of a cell based on 5.0 mol% Nb-doped TiO_2 is significantly better, by about 18.2%, compared to that of a cell based on undoped TiO_2. The as-prepared Nb-doped TiO_2 material is proven in detail to be a better photoanode material than pure TiO_2, and this new synthetic approach using a water-soluble precursor provides a simple and versatile way to prepare excellent photoanode materials.