Interface‐Selective Charge Transport Enables Self‐Powered Vertical WSe ₂ /Perovskite Photodetector Arrays

ABSTRACT Self‐powered photodetectors operating at zero bias are highly attractive for low‐power integrated optoelectronic systems, yet their performance is often limited by inefficient carrier extraction and severe interfacial recombination in 2D/3D heterostructures. Here, we report a vertical Au/WSe ₂ /MAPbBrI ₂ /ZnO/ITO photodetector array enabled by interface‐selective charge transport engineering. By integrating p‐type WSe ₂ with a strongly absorbing mixed‐halide perovskite and introducing ZnO as an electron transport layer, a favorable energy cascade is formed, which is consistent with selective carrier separation under zero bias. Comparative studies reveal that the ZnO interlayer significantly suppresses dark current, enhances rectification behavior, and improves zero‐bias photocurrent by facilitating selective electron extraction and suppressing interfacial recombination. The optimized device exhibits stable switching characteristics and uniform pixel‐to‐pixel response, enabling reliable self‐powered imaging. This work clarifies the critical role of transport‐layer‐assisted interface modulation in vertical 2D/3D heterojunctions and provides a scalable strategy for constructing high‐performance, energy‐efficient photodetector arrays.