Enhanced performance of dye-sensitized solar cells with fluorine doped nanocrystalline TiO₂ as photoanode

In order to enhance the performance of dye-sensitized solar cells (DSSCs), the fluorine doped TiO₂ nanoparticles were employed as photonode. Using TiF₄ as starting material, fluorine atom is introduced into nanocrystalline TiO₂ by a simple method. The TiO₂ nanoparticles with uniform F doping were prepared by hydrothermal method, and were further exploited as the application in DSSCs via doctor-blading technique successfully. In addition, the highest conversion efficiency of 6.30% was achieved under one sun illumination (AM 1.5G, 100 mW/cm²), which is about 13% higher than that of the devices using commercial P25 TiO₂ nanoparticles, the probably reason could mainly ascribed to the improvement in fill factor and open-circuit voltage. Moreover, the mechanism study demonstrated that the improved cell performance could attributed to the higher amount of dye adsorption on TiO₂, the enhanced interfacial charge transfer rate between interconnected TiO₂, higher injection rate from dye to TiO₂ nanoparticles which was induced by the formation of Ti³⁺ and F⁻ ions in the semiconductor, and the reduced recombination at the interfacial face between TiO₂ and electrolyte.