Elucidating surface and bulk emission in 3D hybrid organic – inorganic lead bromide perovskites

Three dimensional (3D) hybrid organic–inorganic lead halide perovskites (HOIP) have emerged in recent years as promising materials for a wide variety of optoelectronic applications. However, the photoluminescence energies in bromide‐based HOIP have been reported to vary in the range from 2.16 to 2.3...

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Main Authors: Chi, Xiao, Leng, Kai, Wu, Bo, Shi, Dong, Choy, Yufong, Chen, Zhongxin, Chen, Zhihui, Yu, Xiaojiang, Yang, Ping, Xu, Qing-Hua, Sum, Tze Chien, Rusydi, Andrivo, Loh, Kian Ping
Other Authors: School of Physical and Mathematical Sciences
Format: Article
Language:English
Published: 2020
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Online Access:https://hdl.handle.net/10356/139722
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-1397222020-05-21T05:12:25Z Elucidating surface and bulk emission in 3D hybrid organic – inorganic lead bromide perovskites Chi, Xiao Leng, Kai Wu, Bo Shi, Dong Choy, Yufong Chen, Zhongxin Chen, Zhihui Yu, Xiaojiang Yang, Ping Xu, Qing-Hua Sum, Tze Chien Rusydi, Andrivo Loh, Kian Ping School of Physical and Mathematical Sciences Science::Physics MAPbBr3 Photoluminescence Three dimensional (3D) hybrid organic–inorganic lead halide perovskites (HOIP) have emerged in recent years as promising materials for a wide variety of optoelectronic applications. However, the photoluminescence energies in bromide‐based HOIP have been reported to vary in the range from 2.16 to 2.35 eV. The occurrence of surface reconstructions due to uncompensated surface ionic charges may change the photo‐physical properties of the surface regions, but this has not been studied in detail. Herein, by performing angle‐dependent photoluminescence (PL) and spectroscopic ellipsometry of single‐crystal as well as polycrystalline HOIP crystals, the intrinsic excitonic emissions from the surface and bulk regions are clearly identified. It is verified that the high energy PL at 2.31 eV originates from a phase‐modified surface region. The large absorption coefficient of perovskite results in signal depletion of the lower energy PL at 2.16 eV, which originates from the bulk. High resolution synchrotron X‐ray diffraction reveals that air‐exposed HOIP crystals form a multilayer structure consisting of PbBr2, and an interfacial layer of orthorhombic phase, while the bulk crystal remains cubic phase. This study provides the unambiguous identification of a phase‐modified surface region with a larger band gap than the bulk and which dominates the excitonic emission in HOIP crystals. ASTAR (Agency for Sci., Tech. and Research, S’pore) MOE (Min. of Education, S’pore) 2020-05-21T05:12:25Z 2020-05-21T05:12:25Z 2018 Journal Article Chi, X., Leng, K., Wu, B., Shi, D., Choy, Y., Chen, Z., . . . Loh, K. P. (2018). Elucidating surface and bulk emission in 3D hybrid organic – inorganic lead bromide perovskites. Advanced Optical Materials, 6(15), 1800470-. doi:10.1002/adom.201800470 2195-1071 https://hdl.handle.net/10356/139722 10.1002/adom.201800470 2-s2.0-85047524460 15 6 en Advanced Optical Materials © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. All rights reserved.
institution Nanyang Technological University
building NTU Library
country Singapore
collection DR-NTU
language English
topic Science::Physics
MAPbBr3
Photoluminescence
spellingShingle Science::Physics
MAPbBr3
Photoluminescence
Chi, Xiao
Leng, Kai
Wu, Bo
Shi, Dong
Choy, Yufong
Chen, Zhongxin
Chen, Zhihui
Yu, Xiaojiang
Yang, Ping
Xu, Qing-Hua
Sum, Tze Chien
Rusydi, Andrivo
Loh, Kian Ping
Elucidating surface and bulk emission in 3D hybrid organic – inorganic lead bromide perovskites
description Three dimensional (3D) hybrid organic–inorganic lead halide perovskites (HOIP) have emerged in recent years as promising materials for a wide variety of optoelectronic applications. However, the photoluminescence energies in bromide‐based HOIP have been reported to vary in the range from 2.16 to 2.35 eV. The occurrence of surface reconstructions due to uncompensated surface ionic charges may change the photo‐physical properties of the surface regions, but this has not been studied in detail. Herein, by performing angle‐dependent photoluminescence (PL) and spectroscopic ellipsometry of single‐crystal as well as polycrystalline HOIP crystals, the intrinsic excitonic emissions from the surface and bulk regions are clearly identified. It is verified that the high energy PL at 2.31 eV originates from a phase‐modified surface region. The large absorption coefficient of perovskite results in signal depletion of the lower energy PL at 2.16 eV, which originates from the bulk. High resolution synchrotron X‐ray diffraction reveals that air‐exposed HOIP crystals form a multilayer structure consisting of PbBr2, and an interfacial layer of orthorhombic phase, while the bulk crystal remains cubic phase. This study provides the unambiguous identification of a phase‐modified surface region with a larger band gap than the bulk and which dominates the excitonic emission in HOIP crystals.
author2 School of Physical and Mathematical Sciences
author_facet School of Physical and Mathematical Sciences
Chi, Xiao
Leng, Kai
Wu, Bo
Shi, Dong
Choy, Yufong
Chen, Zhongxin
Chen, Zhihui
Yu, Xiaojiang
Yang, Ping
Xu, Qing-Hua
Sum, Tze Chien
Rusydi, Andrivo
Loh, Kian Ping
format Article
author Chi, Xiao
Leng, Kai
Wu, Bo
Shi, Dong
Choy, Yufong
Chen, Zhongxin
Chen, Zhihui
Yu, Xiaojiang
Yang, Ping
Xu, Qing-Hua
Sum, Tze Chien
Rusydi, Andrivo
Loh, Kian Ping
author_sort Chi, Xiao
title Elucidating surface and bulk emission in 3D hybrid organic – inorganic lead bromide perovskites
title_short Elucidating surface and bulk emission in 3D hybrid organic – inorganic lead bromide perovskites
title_full Elucidating surface and bulk emission in 3D hybrid organic – inorganic lead bromide perovskites
title_fullStr Elucidating surface and bulk emission in 3D hybrid organic – inorganic lead bromide perovskites
title_full_unstemmed Elucidating surface and bulk emission in 3D hybrid organic – inorganic lead bromide perovskites
title_sort elucidating surface and bulk emission in 3d hybrid organic – inorganic lead bromide perovskites
publishDate 2020
url https://hdl.handle.net/10356/139722
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