Preparation of anatase TiO2 microspheres with high exposure (001) facets as the light-scattering layer for improving performance of dye-sensitized solar cells

Mesoporous anatase TiO2 microspheres with high exposure reactive (001) facets have been synthesized through one-step hydrothermal method. The transmission electron microsocopy images and X-ray diffraction patterns revealed that the TiO2 are high crystalline, uniform shaped and exposed (001) facets. Double layered photoelectrode films with anatase TiO2 microspheres overlayers and TiO2 nanoparticles (P25) underlayers were fabricated. The photoelectric conversion efficiencies of dye-sensitized solar cells (DSSCs) with double layered TiO2 film, TiO2 microspheres film, and commercial P25 film were investigated. It is found that the corresponding double layer photoelectrode-based DSSC yield efficiency of up to 6.49%, higher than those of TiO2 microspheres film-based one (1.81%) and P25 film-based one (4.23%). The improvement of DSSC performance can be attributed to the high specific surface area and excellent light scattering capability by the beneficial unique structure of anatase TiO2 microspheres with high exposure (001) facets as overlayers. Furthermore, the double layered structure can result in the prolonged exciton lifetime, great charge collection efficiency and less charge recombination. This work shows a new photoelectrode design for enhanced energy conversion of DSSCs.