Electric field induced degradation in sky-blue perovskite light-emitting diodes. (October 2022)

• Record Type: Journal Article
• Authors: Sun, Shuang-Qiao; Liu, Cheng; Zhu, Min; Xu, Yan-Lin; He, Wei; Feng, Dan-Dan; Huang, Chen-Chao; Sun, Qi; Xie, Yue-Min; Li, You-Yong; Fung, Man-Keung
• Is Part Of: Materials today energy. Volume 29(2022)
• Publication Date: 2022-10
• Subjects: Phase instability -- Ion migration -- Mixed-halide perovskite -- LEDs; Energy development -- Periodicals; Energy industries -- Periodicals; Power resources -- Periodicals; Energy policy -- Periodicals; Energy development; Energy industries; Energy policy; Power resources; Electronic journals; Periodicals; 621.042
• DOI: 10.1016/j.mtener.2022.101139
• Languages: English
• ISSNs: 2468-6069

Abstract

Abstract: A common strategy to obtain blue- or sky-blue-emitting perovskite light-emitting diodes (PeLEDs) is to incorporate chlorine into the bromine-based perovskites. However, reliability is a crucial and challenging issue. The underlying degradation mechanism of these mixed-halide PeLEDs under continuous electrical bias remains incompletely understood. We unveil that electrical bias can seriously influence the spectral stability and efficiency roll-off of mixed-halide PeLEDs. Through the comprehensive microscopic and spectroscopic studies, we identify several key factors that account for the device degradation: (i) electric-field induced Joule heating; (ii) pinhole formation under electrical bias; and (iii) halogen ion migration toward the interface of electron-transport layer and cathode. We also substantiate that chloride ion migration plays a more dominant role than bromide in the device degradation of the sky-blue mixed-halide PeLEDs. The experimental results are fully supported by our theoretical calculations. These findings provide new insights for a deep understanding of the degradation mechanism of the mixed-halide PeLEDs and pave the way to obtaining stable PeLEDs based on compositional engineering strategies in the future. Graphical abstract: Image 1 Highlights: Phase instability mechanism of the mixed-halide perovskite. Chloride-dominated migration leads to sky-blue LEDs degradation. Critical role of perovskite/ETL interface on the device stability.