Suppressing Halide Segregation in Wide-Band-Gap Mixed-Halide Perovskite Layers through Post-Hot Pressing

Kwang Choi, Min Ju Jeong, Seungmin Lee, Ghaida Alosaimi, Jan Seidel, Jae Sung Yun, Jun Hong Noh

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


Mixed-halide perovskites (MHPs) have attracted attention as suitable wide-band-gap candidate materials for tandem applications owing to their facile band-gap tuning. However, when smaller bromide ions are incorporated into iodides to tune the band gap, photoinduced halide segregation occurs, which leads to voltage deficit and photoinstability. Here, we propose an original post-hot pressing (PHP) treatment that suppresses halide segregation in MHPs with a band gap of 2.0 eV. The PHP treatment reconstructs open-structured grain boundaries (GBs) as compact GBs through constrained grain growth in the in-plane direction, resulting in the inhibition of defect-mediated ion migration in GBs. The PHP-treated wide-band-gap (2.0 eV) MHP solar cells showed a high efficiency of over 11%, achieving an open-circuit voltage (Voc) of 1.35 V and improving the maintenance of the initial efficiency under the working condition at AM 1.5G. The results reveal that the management of GBs is necessary to secure the stability of wide-band-gap MHP devices in terms of halide segregation.

Original languageEnglish
Pages (from-to)24341-24350
Number of pages10
JournalACS Applied Materials and Interfaces
Issue number21
Publication statusPublished - 2022 Jun 1

Bibliographical note

Funding Information:
This work was supported by a National Research Foundation of Korea (NRF) grant funded by the Korean Ministry of Science, ICT and Future Planning (NRF-2020R1A2C3009115, NRF-2017M1A2A2087351, and NRF-2017R1A4A1015022). J.S acknowledges support from the Australian Research Council (ARC) through Discovery Grants and the ARC Center of Excellence in Future Low Energy Electronics Technologies. J.S.Y. acknowledges support from the Australian Center for Advanced Photovoltaics.

Publisher Copyright:
© 2022 American Chemical Society. All rights reserved.


  • hot pressing
  • mixed-halide perovskite
  • photoinduced halide segregation
  • solar cells
  • wide-band-gap perovskite

ASJC Scopus subject areas

  • General Materials Science


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