Enhanced Energy Conversion Efficiency of Me2+-Modified Mesoporous TiO2 Nanoparticles Electrodes for Dye-Sensitized Solar Cells

Mesoporous TiO2 (m-TiO2).nanoparticles were used to prepare the porous electrodes for dye-sensitized solar cells (DSSCs). Experimental results indicate that the MgO covered on TiO2 electrode can act as barrier layer for the interfacial charge recombination processes, whereas some MgO immingled among TiO2 networks due to the part reconstruction of the electrode during the second annealing process can retard the electron transport within electrode. The optimal conversion efficiency is obtained from solar cell fabricated with TiO2 electrode modified with 0.2 M Mg2+ solution, with a 39% improvement in the efficiency as compared to the unmodified one. The suppression of interfacial charge recombination and the enhanced dye adsorption capacity contribute to the improved photovoltaic performance for the Mg2+-modified electrode, and the retardation of electron transport and injection by excessive Mg2+ modification is responsible for the efficiency losses of the corresponding TiO2-based solar cell. This indicates that controlling the extrinsic parameters such as the electron transport and recombination is very important to improve the photovoltaic performance of TiO2-based solar cell.