Photovoltaic Performance Improvement of Dye-Sensitized Solar Cells Based on Mg-Doped TiO2 Thin Films

Mg salts [Mg(NO3)2·6H2O]-doped TiO2 electrodes prepared well-optimized by the hydrothermal method. To prepare the working electrode, the TiO2 or Mg-doped TiO2 slurry was coated onto the fluorine-doped tin oxide glass substrate by the doctor blade method and was then sintered at 450 °C. X-ray photoelectron spectroscopy (XPS) data indicated that the doped Mg ions exist in form of Mg2+, which can play a role as e− or h+ traps and reduce e−/h+ pair recombination rate, The Mott-Schottky plot indicates that the Mg-doped TiO2 photoanode shifts the flat band potential positively. The positive shift of the flat band potential improves the driving force of injected electrons from the LUMO of the dye to the conduction band of TiO2. This study show a photovoltaic efficiency of 7.12%, which is higher than that of the undoped TiO2 thin film (5.62%) and increase short-current by 26.7% from 14.9 mA to 19.1 mA.