Tailor-made ZnO@SnO2 networks for high efficiency photovoltaic devices

ZnO@SnO2 multilayered network was deposited on fluorine doped tin oxide (FTO) glass and applied as photoanode in dye sensitized solar cells whose functional performances are compared with single oxide-based photoanodes made of SnO2 nanoparticles and ZnO microparticles. Multi-oxide photoanodes provide for enhanced photoconversion efficiency (3.31%) as compared with bare SnO2 nanoparticles (1.06%) and ZnO microparticles (1.04%). Improved functional performances of the ZnO@SnO2 layered network are ascribable to partial inhibition of back electron transfer from SnO2 to the redox electrolyte, guaranteed by the ZnO, which acts as a capping layer for the underlying SnO2.