Broadband emission in all-inorganic metal halide perovskites with intrinsic vacancies

Efficient broadband emission related to self-trapped excitons (STEs) in low-dimensional perovskites and double perovskite crystals has attracted great attention due to its potential applications in optoelectronics. However, the formation of STEs in three-dimensional (3D) all-inorganic perovskites (C...

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Bibliographic Details
Published in:Journal of materials chemistry. C, Materials for optical and electronic devices Materials for optical and electronic devices, 2020-10, Vol.8 (4), p.13976-13981
Main Authors: Jiang, Feng, Jiang, Xingxing, Zheng, Weihao, Ouyang, Yu, Zhang, Yushuang, Li, Lihui, Fan, Peng, Zhao, Hepeng, Li, Yang, Jiang, Ying, Zhu, Xiaoli, Zhuang, Xiujuan, Feng, Yexin, Pan, Anlian
Format: Article
Language:English
Subjects:
Broadband
Conduction bands
Crystal defects
Emission
Energy gap
Erbium
Excitons
Metal halides
Optoelectronics
Perovskites
Vacancies
Ytterbium
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Summary:Efficient broadband emission related to self-trapped excitons (STEs) in low-dimensional perovskites and double perovskite crystals has attracted great attention due to its potential applications in optoelectronics. However, the formation of STEs in three-dimensional (3D) all-inorganic perovskites (CsPbX 3 ) is difficult. Here, through the doping of ytterbium (Yb 3+ ) or erbium (Er 3+ ) ions into CsPbX 3 crystals, we observed broadband luminescence from STEs with a linewidth exceeding 200 nm and a Stokes shift of ∼1 eV. Theoretical concepts and experimental studies demonstrated that Pb 2+ in perovskites could be replaced by impure ions. Also, the Pb 2+ substitution defects and adjacent halide vacancies introduced defect states lying just below the conduction band minimum of perovskites. Strong electron-phonon coupling between trapped carriers and deformation of the [PbX 6 ] cage reduced the energy gap of perovskites. Our study sheds new light on the permanent defects induced in extrinsic STEs in 3D inorganic perovskites. It also provides a clear microscopic picture of the underlying mechanism of formation of STEs. Introducing some lanthanide ions with suitable ionic radius into octahedral [PbX 6 ] units to cause permanent lattice distortion and create potential fluctuations in the crystal lattice might facilitate the formation of STEs in CsPbX 3 .
ISSN:2050-7526
2050-7534
DOI:10.1039/d0tc04123h