Anatase TiO2 spheres with high surface area and mesoporous structure via a hydrothermal process for dye-sensitized solar cells

Spherical pure anatase TiO2 spheres with a mesoporous structure and high surface area of up to 116.5 m2 g−1 were prepared by a simple urea-assisted hydrothermal process and investigated as dye-sensitized solar-cell electrodes. Although the particle diameters of the prepared TiO2 spheres ranged from 0.4 to 1.3 μm, due to the high specific surface area, mesoporous TiO2 sphere electrode was obtained with enhanced light harvesting and a larger amount of dye loading. An overall light conversion efficiency of 7.54% under illumination of simulated AM 1.5G solar light (100 mW cm−2) was achieved using the mesoporous TiO2 spheres electrode, which was significantly higher than a commercial Degussa P25 TiO2 nanocrystals electrode (5.69%).