Sterically Suppressed Phase Segregation in 3D Hollow Mixed-Halide Wide Band Gap Perovskites

Luke Grater, Mingcong Wang, Sam Teale, Suhas Mahesh, Aidan Maxwell, Yanjiang Liu, So Min Park, Bin Chen, Frédéric Laquai, Mercouri G. Kanatzidis, E. Sargent

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Band gap tuning in mixed-halide perovskites enables efficient multijunction solar cells and LEDs. However, these wide band gap perovskites, which contain a mixture of iodide and bromide ions, are known to phase segregate under illumination, introducing voltage losses that limit stability. Previous studies have employed inorganic perovskites, halide alloys, and grain/interface passivation to minimize halide segregation, yet photostability can be further advanced. By focusing on the role of halide vacancies in anion migration, one expects to be able to erect local barriers to ion migration. To achieve this, we employ a 3D "hollow" perovskite structure, wherein a molecule that is otherwise too large for the perovskite lattice is incorporated. The amount of hollowing agent, ethane-1,2-diammonium dihydroiodide (EDA), varies the density of the hollow sites. Photoluminescence measurements reveal that 1% EDA in the perovskite bulk can stabilize a 40% bromine mixed-halide perovskite at 1 sun illumination intensity. These, along with capacitance-frequency measurements, suggest that hollow sites limit the mobility of the halide vacancies.
Original languageEnglish (US)
Pages (from-to)6157-6162
Number of pages6
JournalThe Journal of Physical Chemistry Letters
DOIs
StatePublished - Jun 27 2023

ASJC Scopus subject areas

  • General Materials Science

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