Improving the Operational Stability of Near‐Infrared Quasi‐2D Perovskite Light‐Emitting Diodes by Cation Engineering

Abstract Although organic metal halide perovskite light‐emitting diodes (PeLEDs) have been developed rapidly in recent years, their commercialization and further applications are still hindered by ion migration‐induced inferior operational stability. Although the formation of a quasi‐2D structure is a well‐known solution that can efficiently suppress ion migration, the operation lifetime improvement is still limited. In this study, long‐chain phenylbutanammonium is used to replace the commonly used phenethylammonium as the L‐site cations. With large steric hindrance, ion migration inside the PeLEDs is effectively suppressed. Consequently, the PeLED with near‐infrared emission at 763 nm exhibited an operational lifetime ( T 90 ) of up to 5.3 h, which is 53‐fold higher than that of the control device. This study demonstrates the feasibility of significant stability improvement using a simple cation engineering strategy for PeLEDs.