Degradation and self-repairing in perovskite light-emitting diodes

One of the most critical challenges in perovskite light-emitting diodes (PeLEDs) lies in poor operational stability. Although field dependent ion migration is believed to play an important role in the operation of perovskite optoelectronic devices, a complete understanding of how it affects the stability of PeLEDs is still missing. Here, we report a unique self-repairing behavior that the electroluminescence of moderately degraded PeLEDs can almost completely restore to their initial performance after resting. We find that the accumulated halides within the hole transport layer undergo back diffusion toward the surface of the perovskite layer during resting, repairing the vacancies and thus resulting in electroluminescence recovery. These findings indicate that one of the dominant degradation pathways in PeLEDs is the generation of halide vacancies at perovskite/hole transport layer interface during operation. We thus further passivate this key interface, which results in a high external quantum efficiency of 22.8% and obviously improved operational stability.

Automated summary

One of the critical challenges in perovskite light-emitting diodes (PeLEDs) is poor operational stability, but a unique self-repairing behavior has been discovered where the electroluminescence of moderately degraded PeLEDs can almost completely restore after resting. By understanding the back diffusion of accumulated halides, which repair vacancies in the perovskite layer, the operational stability of PeLEDs can be significantly improved by passivating the key interface.