Facile Synthesis of Mesoporous Tin Oxide Spheres and Their Applications in Dye-Sensitized Solar Cells

Mesoporous tin oxide spheres (MS-SnO 2 ) with a main size ranging from 100 to 800 nm are synthesized via a simple solution route. These spheres consist of packed nanocrystals and possess a specific surface area of 29.4 m 2 ·g –1 and a main pore size of about 4 nm. Due to large particle size, high specific surface area, and good intercrystalline connections, a dye-sensitized solar cell (DSSC) based on the MS-SnO 2 film photoanode shows an energy conversion efficiency of 4.97%, which is higher than that of a DSSC based on current SnO 2 nanoparticle film photoanodes. On the other hand, the photovoltaic performance of the DSSC can be improved by modifying the photoanode with a TiO 2 blocking layer and TiCl 4 post-treatment.