Shell-Thickness-Modulated Charge Carrier Transfer in Au Nanocube@CdS Core–Shell Nanostructures for Plasmon-Driven Photocatalysis

The development of highly efficient photocatalysts for the utilization of solar energy has been extensively explored in the past few decades. Due to the strong light-matter interaction in plasmonic nanostructures, the combination of plasmonic nanomaterials with other poor light-absorbing catalytic materials presents a promising strategy for expanding the scope of light-driven heterogeneous catalysis. Although the photocatalytic performance of these hybridized structures has been greatly improved, how to regulate the charge carrier transfer efficiency in these heterostructures is still ambiguous. In this work, we prepared a metal-semiconductor core-shell heterostructure through precisely coating a thin layer of CdS onto the gold nanocube (AuNC) surface. A noticeable increase in photoelectrical response from the core-shell structure relative to either AuNCs or pure CdS nanoparticles can be observed in photocurrent generation efficiency, electron lifetime, and charge separation efficiency. More importantly, the photoelectrical responses can be well regulated by changing the semiconductor shell thickness on the nanocube surface. An optimum shell thickness for the light-driven photocatalytic reaction is around 8.3 nm, which exhibits the highest charge carrier transfer efficiency and hot-electron generation rate.