Grain Size Influences Activation Energy and Migration Pathways in MAPbBr3 Perovskite Solar Cells

Lucie McGovern, Isabel Koschany, Gianluca Grimaldi, Loreta A. Muscarella, Bruno Ehrler

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Ion migration in perovskite layers can significantly reduce the long-term stability of the devices. While perovskite composition engineering has proven an interesting tool to mitigate ion migration, many optoelectronic devices require a specific bandgap and thus require a specific perovskite composition. Here, we look at the effect of grain size to mitigate ion migration. We find that in MAPbBr3 solar cells prepared with grain sizes varying from 2 to 11 μm the activation energy for bromide ion migration increases from 0.17 to 0.28 eV. Moreover, we observe the appearance of a second bromide ion migration pathway for the devices with largest grain size, which we attribute to ion migration mediated by the bulk of the perovskite, as opposed to ion migration mediated by the grain boundaries. Together, these results suggest the beneficial nature of grain engineering for reduction of ion migration in perovskite solar cells.
Original languageEnglish
Pages (from-to)2423-2428
JournalThe journal of physical chemistry letters
Volume12
Issue number9
DOIs
Publication statusPublished - 11 Mar 2021
Externally publishedYes

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