Frequency-regulated pulsed electrodeposition of CuInS₂ on ZnO nanorod arrays as visible light photoanodes

Vertically aligned ZnO nanorod arrays on a fluorine doped tin oxide (FTO) substrate were uniformly coated with visible light active CuInS₂ nanoparticles using electrodeposition regulated by using an optimized frequency. As the diffusion of the fresh metallic precursor to the bottom of the one-dimensional nanostructure is the major challenge during electrodeposition, frequency tuning has demonstrated its effectiveness in balancing the diffusion and deposition of the secondary component (CuInS₂) on the one-dimensional substrate (ZnO). The high quality of the heterojunction between CuInS₂ and ZnO together with their intimate interaction facilitated efficient charge shuttling from CuInS₂ to ZnO to yield a four-fold visible light response compared with traditionally synthesized CuInS₂-ZnO nanostructures.