Degradation and self-repairing in metal halide perovskite light-emitting diodes
Weidong Xu a
a Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping, Sweden, Linköping University SE-581 83, Linköping, Sweden
Proceedings of nanoGe Fall Meeting 2021 (NFM21)
#PerFun21. Perovskites I: Solar Cells, Lighting, and Related Optoelectronics
Online, Spain, 2021 October 18th - 22nd
Organizers: Eva Unger and Feng Gao
Poster, Weidong Xu, 268
Publication date: 23rd September 2021

Despite the rapid improvement in efficiencies, achieving long-term reliable perovskite light-emitting diodes (PeLEDs) remains challenging, which impedes their practical applications. Further improvements in stability require a more fundamental understanding of the dominant degradation pathways in state-of-the-art PeLEDs. we report a unique self-repairing behaviour that the electroluminescence of moderately degraded PeLEDs can almost completely restore to their initial performance after resting. This phenomenon arises from the electrostatic potential driven back diffusion of halides within the hole transport layer toward the interface of perovskite, a process that repairs the halide vacancies at the interface and results in the self-annihilation of trap states. In this regard, we demonstrate that one of the dominant degradation pathways in state-of-the-art perovskite light-emitting diodes is the generation of halide vacancies at the perovskite/hole transport layer interface caused by field-dependent ion-drifting during operation. We use interfacial engineering and achieve a record EQE of 22.8% with obvious improved operational stability. Our findings not only reveal an encouraging phenomenon for long term reliability of PeLEDs, but also provide a guideline for more targeted material and device optimization.



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