Core-shell nanorods film of p-CuZnS/n-TiO2 with boosting interfacial charge separation for sensitive photoelectrochemical photodetector

Copper zinc sulphide (CZS) due to high conductivity, fast photoresponse and good stability has attracted rising attention in optoelectronic field. Constructing heterojunctions with rational energy bands alignment can accelerate carrier separation to improve the performance of CZS-based photoelectric device. Herein, p-CZS/n-TiO 2 core-shell nanorods heterojunction film was successfully fabricated for the first time. CZS nanoparticles (NPs) were directly loaded on the surface of TiO 2 nanorods (NRs) through a simple chemical bath deposition. Photoelectrochemical (PEC) photodetector based on CZS/TiO 2 composite film was designed and interfacial charge kinetics has also been investigated. The CZS/TiO 2 PEC device exhibits fast response speed of 95/56 ms, high responsivity of 7.1 mA W -1 and detectivity of 5.6 × 10 12 Jones at a bias voltage of 1 V. The light on/off ratio of self-powered CZS/TiO 2 PEC device achieves 5.6 × 10 3 , nearly 30.4 times higher than bare CZS PEC device. Furthermore, the photodetection performance of the CZS/TiO 2 PEC device can be effectively regulated by light power density and environment conditions, promoting its adaptability in multifarious practical applications. The findings suggest that CZS/TiO 2 heterostructure film devices have great potential for high-performance and energy-efficient PEC photodetectors.