In situ decoration of CuSCN nanorod arrays with carbon quantum dots for highly efficient photoelectrochemical performance

In this work, the in situ decoration of CuSCN nanorod thin films with carbon quantum dots (CQDs) was achieved through a one-pot electrochemical deposition process. The hybridization of CQDs would not change the nanorod structure and p-type characteristic of CuSCN thin film. Compared with the pristine CuSCN thin film, the CQDs/CuSCN composite thin film exhibited significantly improved photoelectrochemical (PEC) activities. The photocurrent intensity of the composite thin film electrode was approximately 6.5 times that of the CuSCN thin film electrode. The improved PEC activities could be ascribed to the highly efficient generation, separation and migration of excited charge carriers derived from the decoration of CQDs on the surface of CuSCN nanorods, as verified by the electrochemical impedance spectra (EIS), photoluminescence, charge extraction, intensity-modulated photocurrent spectroscopy (IMPS) and intensity-modulated photovoltage spectroscopy (IMVS) measurements. The superior PEC properties of the CQDs/CuSCN composite thin film make it a promising hole transporting material or photocathode material for practical PEC applications including solar cells and PEC water splitting.