Air-Stable and Self-Driven Perovskite Photodiodes with High On/Off Ratio and Swift Photoresponse

Recent years have witnessed rapid developments in organic-inorganic hybrid perovskites, among which 2D Ruddlesden-Popper (RP) perovskites stand out due to their outstanding ambient stability. In photodetector applications, 2D RP perovskites are mostly limited to lateral device configuration because of their preferred in-plane charge transportation within quantum well structures. In this work, the low-temperature solution construction of 2D RP perovskite-based photodiodes in vertical device architecture is demonstrated. The paradigm phenylethylamine (PEA) spacer cation-based 2D perovskites are fabricated and optimized by exploiting a combination of a NH4Cl additive and dimethyl sulfoxide solvent (DMSO) solvent. They show increased crystallinity, extended photoluminescence lifetimes, and importantly a generation of 3D phases embedded within 2D perovskites, which efficiently promotes charge transfer. As a result, the photodetectors exhibit a high on/off ratio up to 2 x 10(4), a large photocurrent of 0.34 mA cm(-2), and rapid rise (5.8 ms) and decay time (4.6 ms). Of critical importance is the outstanding film/device stabilities demonstrated by storage in air (at 25 degrees C with 60% relative humidity) for 15 days as well as under UV illumination for 1.5 h and after 1500 bending cycles on flexible substrate.