Journal article
Polarized twin walls in a halide perovskite
- Abstract:
- Halide perovskites have emerged as promising materials for next-generation photovoltaics, laser sources, and X-ray detectors. There is intense debate as to whether some photoactive halide perovskites exhibit ferroelectric behavior and whether it might be possible to utilize the bulk photovoltaic effect to enhance the performance of halide perovskite solar cells. Here, using low-dose scanning transmission electron microscopy, we identify ferroelastic twin walls in vapor-deposited CsPbI3 thin films, parallel to {110} and {112}. Remarkably, despite CsPbI3 being centrosymmetric and nonpolar, we observe directly that Pb atoms shift at {110} twin walls driving a local ferroelectric-like polarization. These polar twin walls form an intrinsic array of nanoscale interfaces, spaced ~30 to 50 nm apart, embedded within the nonpolar perovskite lattice. In contrast, {112} twin walls do not show a polar displacement of Pb but strongly suppress octahedral tilt and off-center Cs atom displacements, revealing a different untapped structural degree of freedom. These findings reveal previously hidden nanoscale polarization in halide perovskite semiconductors, opening opportunities for enhanced conductivity and photovoltaic behavior through domain wall engineering.
- Publication status:
- Published
- Peer review status:
- Peer reviewed
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- Files:
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(Preview, Accepted manuscript, pdf, 2.4MB, Terms of use)
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(Preview, Supplementary materials, pdf, 3.8MB, Terms of use)
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- Publisher copy:
- 10.1073/pnas.2610011123
Authors
+ Australian Research Council
More from this funder
- Funder identifier:
- https://ror.org/05mmh0f86
- Grant:
- LE170100118
- Grant:
- FL220100202
- Grant:
- LE0454166
+ Engineering and Physical Sciences Research Council
More from this funder
- Funder identifier:
- https://ror.org/0439y7842
- Grant:
- EP/M022900/1
- Grant:
- EP/X038777/1
- Grant:
- UKRI1487
- Grant:
- 2929117
- Grant:
- 2676528
- Publisher:
- National Academy of Sciences
- Journal:
- Proceedings of the National Academy of Sciences More from this journal
- Volume:
- 123
- Issue:
- 45
- Article number:
- e2610011123
- Publication date:
- 2026-11-05
- Acceptance date:
- 2026-09-21
- DOI:
- EISSN:
-
1091-6490
- ISSN:
-
0027-8424
- Language:
-
English
- Keywords:
- Pubs id:
-
2494082
- Local pid:
-
pubs:2494082
- Deposit date:
-
2026-11-06
- ARK identifier:
Terms of use
- Copyright holder:
- Li et al.
- Copyright date:
- 2026
- Rights statement:
- © 2026 the Author(s). Published by PNAS.
- Notes:
- The author accepted manuscript (AAM) of this paper has been made available under the University of Oxford's Open Access Publications Policy, and a CC BY public copyright licence has been applied.
- Licence:
- CC Attribution (CC BY)
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