Type-II CsPbBr₃/ZnS Heterostructured Nanocrystals for High-Performance Self-Powered Photodetector

Metal halide perovskites have emerged as promising functional materials for high-performance photodetectors owing to their exceptional properties, including high-absorption coefficient, low-exciton binding energy, and near-unity photoluminescence quantum yields. However, their practical applications in photodetection remain constrained by intrinsic carrier recombination losses. Herein, we report the rational design of type-II CsPbBr3/ZnS heterostructured nanocrystals (NCs) through interfacial band engineering to address this challenge. Advanced characterization combining transmission electron microscopy, ultraviolet photoelectron spectroscopy, and density functional theory calculations confirms the formation of a staggered band alignment at the heterointerface. This unique electronic structure facilitates fast charge separation and inhibits carrier recombination compared to pristine CsPbBr3 NCs. Benefiting from the advantages of CsPbBr3/ZnS heterostructured NCs, we demonstrate a self-powered photodetector with excellent detection capability under 365 nm illumination: photosensitivity of 1.38 × 104, responsivity of 37.5 mA/W, and specific detectivity of 1.21 × 1012 Jones at zero bias. The interfacial engineering strategy presented in this work establishes a universal approach for developing high-efficiency perovskite optoelectronics with tailored charge transport dynamics.