Ordered Mesoporous SnO2-Based Photoanodes for High-Performance Dye-Sensitized Solar Cells

Ordered mesoporous SnO2 with three-dimensional bicontinuous cubic mesostructure, high surface area, and crystalline frameworks was synthesized by the solvent-free infiltration of tin precursor in KIT-6 silica template and employed as a photoanode in dye-sensitized solar cells (DSSCs). It is shown that coating an ultrathin TiO2 or Al2O3 layer on mesoporous SnO2 photoanode greatly improves the open-circuit voltage, short-circuit current, and fill factor, leading to more than a 3-fold improvement in the energy conversion efficiency. The superior photovoltaic performance of surface modified mesoporous SnO2 photoanode is mainly the result of inhibited electron recombination caused by passivation of reactive surface states and increased dye loading. Control cells fabricated with conventional nanoparticle SnO2/TiO2 photoanode exhibit a similar trend but with about 30% lower energy conversion efficiency, which is mainly because of limitations due to low dye loading and poor light scattering.