Illumination-induced phase segregation and suppressed solubility limit in Br-rich mixed-halide inorganic perovskites

Yutao Wang, Xinwei Guan, Weijian Chen, Jack Yang*, Long Hu, Jiong Yang, Sean Li, Kourosh Kalantar-Zadeh, Xiaoming Wen, Tom Wu*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)


Mixing halides in perovskites has emerged as an effective strategy for tuning the band gap for optoelectronic applications and tackling the stability bottleneck. However, notable photoluminescence evolution has been observed in mixed-halide perovskites under external stimuli such as light illumination, which is attributed to phase segregation with halide inhomogeneity. In this work, we investigate the light illumination effect on the optical properties of all-inorganic mixed-halide perovskite CsPb(Br1-xIx)3 in the Br-rich regime. It is found that the critical iodine concentration, defined as the solubility limit against phase segregation, is significantly suppressed by light illumination to an extremely low level (x < 0.025), although the formation energy calculation suggests a wide range of halide mixing. Furthermore, at high I concentrations (x ≥ 0.2), the phase segregation can be rectified via dark storage within 1 h, but much slower and incomplete reversibility is observed at lower I concentrations. In the all-inorganic mixed-halide perovskite films, the light-induced phase segregation above the solubility limit is also accompanied by a monotonous increase in fluorescence lifetime. Last, we propose that light-induced phase segregation enables the potential application of encrypting erasable information in perovskite films with the aid of tailored light exposure and photoluminescence mapping.

Original languageEnglish
Pages (from-to)38376-38385
Number of pages10
JournalACS Applied Materials and Interfaces
Issue number34
Publication statusPublished - 26 Aug 2020
Externally publishedYes

Bibliographical note

Funding Information:
This work was supported by the UNSW SHARP Project (RG163043) and Australian Research Council (DP190103316).

Publisher Copyright:
Copyright © 2020 American Chemical Society.

Copyright 2020 Elsevier B.V., All rights reserved.


  • information encryption
  • inorganic halide perovskite
  • mixed-halide perovskite
  • phase segregation
  • solubility limit
  • thin film


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