Tri-System Interlocking Top-Encased Structures Enabled Highly Stable Tin-Lead Perovskite Photodetection Arrays

Tin-lead binary perovskites show a very broad spectral bandwidth from ultraviolet (UV) to near-infrared (NIR) and outstanding optoelectronic properties for photodetection applications. However, the oxidation tendency of the divalent tin easily causes severe vacancies and defects, deteriorating the efficiency and stability of the device. In this work, without involving any costly synthesis of additives, a natural reducing agent of chlorogenic acid is proposed to establish a unique top-encased tri-system interlocking structure in tin-lead perovskites. Benefiting from the synergetic closed-loop interactions among functional groups of the additive with perovskites, tin-lead perovskite photodetectors (PDs) are demonstrated with improvements in energy-level alignment, antioxidation, and defect suppression and passivation. Finally, the self-powered perovskite NIR PDs present a high external quantum efficiency of ≈76%, an outstanding specific detectivity of 2 × 10¹³ Jones at 940 nm, and a large linear dynamic range of 222 dB, along with good stability maintaining 96% of initial photocurrent after 127 days for the unencapsulated PDs storing under N₂ atmosphere. By integrating with a 64 × 64 thin-film transistor array, the tin-lead perovskite image sensor exhibits clear and accurate imaging properties, paving the way for a wide range of high-detectivity and high-resolution imaging applications.