Facile fabrication of CdS/CdSe core–shell nanowire heterostructure for solar cell applications

Abstract

Hierarchical one-dimensional CdS nanowires (NWs)/CdSe core–shell heterostructure have been synthesized through a simple wet chemical approach. The formation of CdS NWs/CdSe core–shell has been confirmed by structural, morphological and optical analysis. Fascinatingly, an optimum number of CdSe nanoparticles loaded over CdS NWs boosts the device efficiency five times than a bare CdS NW structure. The effect of increasing the CdSe SILAR cycles over CdS induces red shift in the absorption wavelength along with quenching, which leads to the negative shift of the conduction band, and hence, increases the electron lifetime, as analyzed by photoluminescence, external quantum efficiency and Mott–Schottky studies. Interestingly, a discrepancy has been found in the device performance with an increase in the SILAR cycles beyond the optimum condition. The reason behind this fact has been investigated through different comprehensive photoelectrochemical characterization and discussed herein.