Ion Migration Heals Trapping Centers in CH3NH3PbBr3 Perovskite

Supriya Ghosh, Suman Kalyan Pal*, Khadga J. Karki, Tönu Pullerits

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

We investigate the local changes in photophysics at different microregions of a methylammonium lead bromide (MAPbBr3) perovskite crystal under illumination. Our results show that the emission from the structurally homogeneous region is blue-shifted compared to the emission from the inhomogeneous regions. The yield and spectrum of the emission from the structurally homogeneous region do not vary with the illumination time, whereas distinct light-induced changes are seen in the spectra from the inhomogeneous region. The changes in the spectra at long illumination time suggest that ion-migration inhibits the emission from the inhomogeneous regions. The measurements of the emission lifetime suggest that the emission from the inhomogeneous regions is dominated by the defect-related emission at short illumination times and the band-to-band emission at the longer illumination times. Our work provides direct evidence for the light-induced healing of the defect centers, which is important in the design of photoactive devices of MAPbBr3.

Original languageEnglish
Pages (from-to)2133-2139
Number of pages7
JournalACS Energy Letters
Volume2
Issue number9
DOIs
StatePublished - 8 Sep 2017
Externally publishedYes

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