Macro-mesoporous TiO2 Microspheres for Highly Efficient Dye-Sensitized Solar Cells

In this work, the novel macro-mesoporous TiO2, microspheres (MMTMs) have been synthesized via a spray drying route with fumed silica (FS) as template, followed by calcination and etching. The as-synthesized MMTMs have unique bimodal porous structures of macropores Origin from VS template and mesopores accumulated by TiO2 nanoparticles. The macro-mesoporous structure endows the TiO2 microspheres with better surface area and wonderful light scattering property. When MMTMs are employed as the photoelectrodes of dye-sensitized solar cells, short-circuit current and open-circuit voltage are both improved and the high power conversion efficiency of 8.68% is obtained eventually, which is much higher than P25 photoelectrode. The excellent performance can be attributed to the excellent light-scattering property, better diffusion of electrolyte as well as superior electron transport owing to the unique bimodal pore structure and the dense packed of the internal nanoparticles of MMTMs.