Suppression of charge recombination rate in nanocrystalline SnO2 by thin coatings of divalent oxides in dye-sensitized solar cells

Abstract

The core-shell SnO2@AO (A = Ni, Cu, Zn and Mg) films were prepared and the effects of coatings on photovoltaic properties were investigated. Studies on X-ray photoelectron spectroscopy, energy dispersive X-ray analysis and transmission electron microscopy showed the formation of divalent oxides on the surface of SnO2 nanoparticles. It was commonly observed that all the dye-sensitized core-shell films exhibited higher photovoltage than the bare SnO2 film. Transient photovoltage measurements confirmed that the improved photovoltages were related to the decreased time constants for electron recombination.