2D Ruddlesden‐Popper Perovskite Photodetector with 0.1 pA Dark Current Enabled by Asymmetric Schottky Contacts

Abstract 2D Ruddlesden‐Popper (RP) phase perovskite single crystals feature significant optoelectronic properties owing to their unique structural characteristics. Introducing an asymmetric electrode configuration on 2D layered perovskites is expected to exhibit interesting interfacial contact phenomena and greatly enhance their optoelectronic performance. Herein, 2D RP‐phase perovskite (PEA) ₂ PbBr ₄ (PPB) single‐crystalline microplates, with thickness ranging from ≈60 to ≈350 nm, are prepared by the liquid–air interfacial method. Asymmetric contact barriers are constructed with two different metal electrodes on the perovskite microplates to improve the photodetection performance and obtain a preferable self‐powered photodetection capability. The optimized asymmetric barrier and excellent band alignment facilitate efficient photogenerated charge dissociation and extraction, boosting the biased photocurrent by 5.59 × 10 ⁴ times compared to symmetric electrode devices. Crucially, by constructing contact barriers with two different metal electrodes, a preferable self‐powered (PEA) ₂ PbBr ₄ photodetector is achieved. The asymmetric photodetector exhibits a high on/off ratio of 7.69 × 10 ³ and maintains an ultralow dark current (3.28 × 10 ⁻¹³ A) with high photocurrent (2.41 × 10 ⁻⁹ A) in self‐powered mode. This study highlights a simple and effective strategy using asymmetric electrodes to improve the performance of a 2D RP‐phase perovskite photodetector, advancing the understanding of carrier transport dynamics and material‐electrode contact behavior of 2D perovskites.