Enhanced Near‐Infrared Perovskite Light‐Emitting Devices by Introducing Choline Chloride Layer

Abstract The existing interface defect states between perovskite and the transport layer is one of the dominant reasons to limit the performance of near‐infrared (NIR) perovskite light‐emitting devices (PeLEDs). Herein, a quaternary ammonium halide choline chloride layer is introduced to improve the wettability of the hole transport layer (HTL) and passivate defect states. As a consequence, the performance of the NIR PeLEDs is obviously enhanced. A maximum output power density of 4.7 mW cm −2 has been achieved by optimizing the concentration of choline chloride. Furthermore, the alternating current (AC) driving mode is introduced to reduce thermal degradation and charge accumulation in the interface region. It is demonstrated that the emission intensity as well as the stability of PeLEDs can be further improved.