Lattice compression increases the activation barrier for phase segregation in mixed-halide perovskites
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
The bandgap tunability of mixed-halide perovskites makes them promising candidates for light-emitting diodes and tandem solar cells. However, illuminating mixed-halide perovskites results in the formation of segregated phases enriched in a single halide. This segregation occurs through ion migration, which is also observed in single-halide compositions, and whose control is thus essential to enhance the lifetime and stability. Using pressure-dependent transient absorption spectroscopy, we find that the formation rates of both iodide- and bromide-rich phases in MAPb(BrxI1–x)3 reduce by 2 orders of magnitude on increasing the pressure to 0.3 GPa. We explain this reduction from a compression-induced increase of the activation energy for halide migration, which is supported by first-principle calculations. A similar mechanism occurs when the unit cell volume is reduced by incorporating a smaller cation. These findings reveal that stability with respect to halide segregation can be achieved either physically through compressive stress or chemically through compositional engineering.
Date Issued
2020-10-09
Date Acceptance
2020-09-01
Citation
ACS Energy Letters, 2020, 5 (10), pp.3152-3158
ISSN
2380-8195
Publisher
American Chemical Society (ACS)
Start Page
3152
End Page
3158
Journal / Book Title
ACS Energy Letters
Volume
5
Issue
10
Copyright Statement
© 2020 American Chemical Society. This is an open access article published under a Creative Commons Non-Commercial No
Derivative Works (CC-BY-NC-ND) Attribution License, which permits copying and
redistribution of the article, and creation of adaptations, all for non-commercial purposes.
Derivative Works (CC-BY-NC-ND) Attribution License, which permits copying and
redistribution of the article, and creation of adaptations, all for non-commercial purposes.
Identifier
https://pubs.acs.org/doi/10.1021/acsenergylett.0c01474
Publication Status
Published
Date Publish Online
2020-09-01