Synthesis of Au-SiO2 asymmetric clusters and their application in ZnO nanosheet-based dye-sensitized solar cells.

A facile and novel process modified from the Stöber method has been developed to prepare Au-SiO2 asymmetric clusters with a number of Au nanoparticles off-center. The Au-SiO2 asymmetric clusters exhibit the wanted surface plasmons along with increases in the plasmonic near field and optical extinction efficiency. They are incorporated into dye-sensitized solar cells (DSSCs) consisting of ZnO nanosheets as the photoanode, where the surface plasmonic effect on DSSCs performance arising from the Au-SiO2 asymmetric clusters is investigated. An enhancement in both the photocurrent and overall energy conversion efficiency is observed, arising from the improvement in light harvesting.