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Asynchronous Photoexcited Electronic and Structural Relaxation in Lead-Free Perovskites

Liu, Cunming ; Wang, Yingqi ; Geng, Huifang ; Zhu, Taishan ; Ertekin, Elif ; Gosztola, David ; Yang, Sizhuo ; Huang, Jier ; Yang, Bin and Han, Keli , et al. (2019) In Journal of the American Chemical Society 141(33). p.13074-13080
Abstract

Vacancy-ordered lead-free perovskites with more-stable crystalline structures have been intensively explored as the alternatives for resolving the toxic and long-term stability issues of lead halide perovskites (LHPs). The dispersive energy bands produced by the closely packed halide octahedral sublattice in these perovskites are meanwhile anticipated to facility the mobility of charge carriers. However, these perovskites suffer from unexpectedly poor charge carrier transport. To tackle this issue, we have employed the ultrafast, elemental-specific X-ray transient absorption (XTA) spectroscopy to directly probe the photoexcited electronic and structural dynamics of a prototypical vacancy-ordered lead-free perovskite... (More)

Vacancy-ordered lead-free perovskites with more-stable crystalline structures have been intensively explored as the alternatives for resolving the toxic and long-term stability issues of lead halide perovskites (LHPs). The dispersive energy bands produced by the closely packed halide octahedral sublattice in these perovskites are meanwhile anticipated to facility the mobility of charge carriers. However, these perovskites suffer from unexpectedly poor charge carrier transport. To tackle this issue, we have employed the ultrafast, elemental-specific X-ray transient absorption (XTA) spectroscopy to directly probe the photoexcited electronic and structural dynamics of a prototypical vacancy-ordered lead-free perovskite (Cs3Bi2Br9). We have discovered that the photogenerated holes quickly self-trapped at Br centers, simultaneously distorting the local lattice structure, likely forming small polarons in the configuration of Vk center (Br2 - dimer). More significantly, we have found a surprisingly long-lived, structural distorted state with a lifetime of ∼59 μs, which is ∼3 orders of magnitude slower than that of the charge carrier recombination. Such long-lived structural distortion may produce a transient "background" under continuous light illumination, influencing the charge carrier transport along the lattice framework. ©

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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of the American Chemical Society
volume
141
issue
33
pages
13074 - 13080
publisher
The American Chemical Society (ACS)
external identifiers
  • scopus:85071026163
  • pmid:31361482
ISSN
0002-7863
DOI
10.1021/jacs.9b04557
language
English
LU publication?
yes
id
da5956fa-4abe-4b91-8181-7b1ec0776564
date added to LUP
2019-09-12 13:05:04
date last changed
2024-05-15 20:39:34
@article{da5956fa-4abe-4b91-8181-7b1ec0776564,
  abstract     = {{<p>Vacancy-ordered lead-free perovskites with more-stable crystalline structures have been intensively explored as the alternatives for resolving the toxic and long-term stability issues of lead halide perovskites (LHPs). The dispersive energy bands produced by the closely packed halide octahedral sublattice in these perovskites are meanwhile anticipated to facility the mobility of charge carriers. However, these perovskites suffer from unexpectedly poor charge carrier transport. To tackle this issue, we have employed the ultrafast, elemental-specific X-ray transient absorption (XTA) spectroscopy to directly probe the photoexcited electronic and structural dynamics of a prototypical vacancy-ordered lead-free perovskite (Cs<sub>3</sub>Bi<sub>2</sub>Br<sub>9</sub>). We have discovered that the photogenerated holes quickly self-trapped at Br centers, simultaneously distorting the local lattice structure, likely forming small polarons in the configuration of V<sub>k</sub> center (Br<sub>2</sub> <sup>-</sup> dimer). More significantly, we have found a surprisingly long-lived, structural distorted state with a lifetime of ∼59 μs, which is ∼3 orders of magnitude slower than that of the charge carrier recombination. Such long-lived structural distortion may produce a transient "background" under continuous light illumination, influencing the charge carrier transport along the lattice framework. ©</p>}},
  author       = {{Liu, Cunming and Wang, Yingqi and Geng, Huifang and Zhu, Taishan and Ertekin, Elif and Gosztola, David and Yang, Sizhuo and Huang, Jier and Yang, Bin and Han, Keli and Canton, Sophie E. and Kong, Qingyu and Zheng, Kaibo and Zhang, Xiaoyi}},
  issn         = {{0002-7863}},
  language     = {{eng}},
  number       = {{33}},
  pages        = {{13074--13080}},
  publisher    = {{The American Chemical Society (ACS)}},
  series       = {{Journal of the American Chemical Society}},
  title        = {{Asynchronous Photoexcited Electronic and Structural Relaxation in Lead-Free Perovskites}},
  url          = {{http://dx.doi.org/10.1021/jacs.9b04557}},
  doi          = {{10.1021/jacs.9b04557}},
  volume       = {{141}},
  year         = {{2019}},
}