Fabrication of TiO2 Aggregates by Electrospraying and Their Application in Dye-Sensitized Solar Cells

A new process for the fabrication of microsized TiO2 aggregates by electrospraying of a colloidal dispersion of P25 TiO2 nanoparticles is investigated. This method allows for independently control of morphology, size and packing density of the TiO2 aggregates for better dye-loading and electrolyte penetration, efficient light scattering and charge transfer. The resultant aggregates comprised of primary P25 nanoparticles are polydisperse and nearly spherical in shape with 0.4-3 mu m in diameter. When used in dye-sensitized solar cells, the films comprised of TiO2 aggregates show high optical absorption as a result of light scattering, demonstrating more than 20% enhancement in the power conversion efficiency compared to the films made of original P25 nanoparticles under otherwise identical conditions.