Xing Jun et al., Nat. Commun.: Molecular Engineering of High-Efficiency White Perovskite LEDs
Release Date:
2021-08-16 15:36
Source:
Low-dimensional hybrid perovskites exhibit outstanding performance as white-light emitters. Broadband white-light emission originates from self-trapped excitons (STEs). However, the formation mechanism of STEs in perovskites remains poorly understood, and the synthesis of new low-dimensional white perovskites has thus relied primarily on screening large libraries of organic intercalants rather than on rational molecular design.
Xing Jun of Qingdao University of Science and Technology, Weigao Xu of Nanjing University, Lijun Zhang of Jilin University, and others This report describes an atomic substitution strategy to induce the formation of STEs in layered perovskites. Halogen-substituted phenyl molecules are used to synthesize perovskite crystals. The halogen substituents withdraw electrons from the phenyl molecule’s alkyl chain (-R-NH3+), leading to a buildup of positive charge on the -R-NH3+ moiety. This enhances the Coulombic attraction between (-R-NH3+) and (PbBr42-), thereby promoting exciton self-trapping.
The designed white perovskite exhibits a photoluminescence quantum yield of 32%, a color rendering index close to 90, and chromaticity coordinates that closely match those of standard white light. Combined experimental and theoretical studies have provided insights into the formation of STEs in perovskites and will facilitate the rational design of high-performance white perovskites.
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