High‐Sensitivity and Fast‐Response Photomultiplication Type Photodetectors Based on Quasi‐2D Perovskite Films for Weak‐Light Detection

Abstract Photovoltaic photodiodes often face challenges in effectively harvesting electrical signals, especially when detecting faint light. In contrast, photomultiplication type photodetectors (PM‐PDs) are renowned for their exceptional sensitivity to weak signals. Here, an advanced PM‐PD is introduced based on quasi 2D Ruddlesden‐Popper (Q‐2D RP) perovskites, optimized for weak light detection at minimal operating voltages. The abundant traps at the Q‐2D RP surface capture charge carriers, inducing a trap‐assisted tunneling mechanism that leads to the photomultiplication (PM) effect. Deep‐lying trap states within the Q‐2D RP bulk accelerate charge carrier recombination, resulting in an outstanding rise/fall time of 1.14/1.72 µs for the PM‐PDs. The PM‐PD achieves a remarkable response level of up to 45.89 A W⁻¹ and an extraordinary external quantum efficiency of 14400% at −1 V under an illumination of 1 µW cm⁻². The intrinsic high resistance of the Q‐2D perovskite results in a low dark current, enabling an impressive detectivity of 4.23 × 10¹² Jones based on noise current at −1 V. Furthermore, the practical application of PM‐PDs has been demonstrated in weak‐light, high‐rate communication systems. These findings confirm the significant potential of PM‐PDs based on Q‐2D perovskites for weak light detection and suggest new directions for developing low‐power, high‐performance PM‐PDs for future applications.