Tin oxide microspheres with exposed {101} facets for dye-sensitized solar cells: enhanced photocurrent and photovoltage.

Hierarchical SnO2 microspheres with exposed {101} facets are synthesized by a one-pot solvothermal reaction and explored as a scattering layer on top of a SnO2 nanoparticle film for dye-sensitized solar cells (DSCs). The microspheres not only enhance photon harvesting by effective light scattering/reflecting but also improve the energy level of the conduction band edge of the SnO2 photoanode, which leads to a simultaneous increase of the short-circuit photocurrent by 17% and open-circuit photovoltage by 20%. An improved overall conversion efficiency of 3.46% is achieved for DSCs using the SnO2 microspheres, which is the highest value reported so far for pure-SnO2 DSCs. Moreover, the SnO2 -microsphere DSCs exhibit a better photostability than the conventional TiO2 DSCs under simulated full sunlight.