Controlling synthesis of well-crystallized mesoporous TiO2 microspheres with ultrahigh surface area for high-performance dye-sensitized solar cells

In this study, well-crystallized mesoporous anatase TiO2 spheres were prepared by hydrothermal treatment of the titanium diglycolate precursors. These spheres are submicrometer-sized and consist of packed nanocrystallites with diameters of ∼8 nm, and possess a specific surface area of 193 m2 g−1 and main pore sizes of ∼5 nm. We demonstrated that due to the large particle diameters and ultrahigh specific surface areas, mesoporous TiO2 microspheres can enhance the light harvesting within the photoanodes for dye-sensitized solar cells (DSSCs), and meanwhile, their good crystallinity and better interparticle connections caused by partially oriented attachment of primary particles result in the effective charge transport through the film of mesoporous TiO2 spheres. A high light-to-electricity conversion of 8.20% has been achieved, indicating a 40% increase in the conversion efficiency compared to the standard Degussa P25 photoanode.