Size-controlled nanoporous TiO2 spheres with high dye-loading: Facile synthesis and application as scattering layers in dye-sensitized solar cells

Anatase nanoporous TiQ(2) spheres were synthesized via a modified sol-gel method. By controlling the concentration of the precursor, size-controlled nanoporous TiO2 spheres with high dye-loading were achieved. The synthesized spheres with different sizes (100 nm, 175 nm, 225 nm, 475 nm) were used as scattering layers on a TiO2 nanoparticle film by electrophoresis deposition method to form hi-layered dye-sensitized solar cells (DSSCs). Scattering effect of the layers with different sized spheres was studied. It was proved that the 475nm-sized spheres showed optium light scattering effect. Due to the scattering effect, an overall photoelectric conversion efficiency of 6.3% has been achieved, a 30% increase compared with the nanoparticle-based photoanode.