Defect-Related Broadband Emission in Two-Dimensional Lead Bromide Perovskite Microsheets

Low-dimensional hybrid lead halide perovskites (LHPs) with broadband emission (BE) have been developed as promising candidates for single-source white-light-emitting diodes. However, the underlying origin of such BE is poorly understood. Herein, dual-emissive [NH3(CH2)8NH3]­PbBr4 perovskite microshe...

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Bibliographic Details
Published in:The journal of physical chemistry letters 2020-10, Vol.11 (19), p.8157-8163
Main Authors: Li, Xianli, Lian, Xin, Pang, Junhong, Luo, Binbin, Xiao, Yonghong, Li, Ming-De, Huang, Xiao-Chun, Zhang, Jin Zhong
Format: Article
Language:English
Subjects:
Physical Insights into Light Interacting with Matter
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Summary:Low-dimensional hybrid lead halide perovskites (LHPs) with broadband emission (BE) have been developed as promising candidates for single-source white-light-emitting diodes. However, the underlying origin of such BE is poorly understood. Herein, dual-emissive [NH3(CH2)8NH3]­PbBr4 perovskite microsheets (PMSs) with good dispersibility are successfully prepared. Besides the general narrowband emission (NE) originating from free excitons, BE (∼522 nm) is generated under a Br-poor condition, which is not observed in the single-crystal sample. Unlike self-trapped exciton emission, the BE observed in PMSs is experimentally determined to be related to bromide vacancies (VBr), thereby exhibiting quasisaturation under high excitation intensity. Femtosecond transient absorption spectroscopy first shows that the trapping time of the photogenerated electrons by acceptor-like VBr– is ∼15 ps, slower than that by surface defects (
ISSN:1948-7185
1948-7185
DOI:10.1021/acs.jpclett.0c02355