Efficient Dark Current Suppression by Engineering PIET‐Active Discrete Donor–Acceptor Architecture for High‐Sensitivity Semiconductor Photodetectors

Abstract

Abstract High‐sensitivity photodetectors are of paramount importance for astronomy, night vision, and bioimaging. Current methods for enhancing sensitivity still face the challenges of complex preparation processes and the dependence on low‐temperature environments. This work demonstrates that constructing a discrete, donor (D)–acceptor (A) structure and employing the photoinduced electron transfer (PIET) technique may simultaneously reduce dark current and increase photocurrent efficiently, thereby significantly enhancing the detection sensitivity. With this synergetic strategy, a viologen‐based photochromic semiconductor with a discrete bismuth halide structure may reduce its dark current by ≈94% —a reduction far exceeding those reported using external field‐induced modification methods—while simultaneously enhancing the photocurrent by ≈83% after PIET and coloration. This value corresponds to a two‐fold increase of the detection sensitivity ( S ). This finding opens a new effective strategy to explore ultra‐highsensitivity photodetectors and smart semiconductors.