Has the perovskite LED stability problem been solved?†

Significant progress in the stability of metal halide perovskite light emitting diodes (LEDs) has been made in recent years, with impressive increases in record lifetimes. However, a large number of published papers still report half lifetimes, T₅₀, which are significantly shorter compared to reported records. In this perspective, we discuss the stability achievements for different emission ranges and the remaining challenges. Blue LEDs generally exhibit much faster performance degradation compared to other colours, while for near-infrared and green LEDs record half-lifetimes exceeding 30 000 h have been reported. To identify promising approaches towards higher stability devices, we focus on green LEDs and discuss mechanisms of degradation and factors affecting the device stability, focusing on the electrochemical processes and ion migration, and how these processes are affected by the perovskite composition and device architecture.