High‐Performance Photoconductive Unidirectional Rectification in Perovskite Single‐Crystal

ABSTRACT The essence of unidirectional rectification (UR) photoresponse lies in the directional transport of carriers, and the unique shallow surface carrier accumulation effect, coupled with the vertical geometry of large‐sized single‐crystals (SCs), provides a novel device configuration for realizing this characteristic. In this work, we constructed vertical photodetectors (PDs) based on 2.2 mm‐thick MAPbBr 3 and MAPbI 3 SCs. Under intense illumination (1524.8 mW/cm 2 ), these devices exhibited significant UR photoresponse characteristics, with a rectification ratio reaching two orders of magnitude. By fabricating a MAPbI 3 thin‐layer/MAPbBr 3 SC hybrid configuration, the heterojunction effect further enhanced the UR performance to 3–4 orders of magnitude, setting a new record. The hybrid‐configuration PD achieved a high responsivity of 752 A/W under an ultra‐low excitation power density (9 × 10 − 4 mW/cm 2 ). The theoretical specific detectivity calculated based on the shot noise limit is 4.68 × 10 1 5 Jones, and the external quantum efficiency is 230985%, representing an overall performance improvement of 1–2 orders of magnitude compared to homo‐crystal devices.