Inhomogeneous Defect Distribution in Mixed-Polytype Metal Halide Perovskites

Young Won Woo, Zhenzhu Li, Young Kwang Jung, Ji Sang Park, Aron Walsh

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


The competition between corner-, edge-, and face-sharing octahedral networks is a cause of phase inhomogeneity in metal halide perovskite thin-films. Here we probe the charged iodine vacancy distribution and transport at the junction between cubic and hexagonal polytypes of CsPbI3 from first-principles materials modeling. We predict a lower defect formation energy in the face-sharing regions, which correlates with a longer Pb-I bond length and causes a million-fold increase in local defect concentration. These defects are predicted to be more mobile in the face-sharing regions with a reduced activation energy for vacancy-mediated diffusion. We conclude that hexagonal phase inclusions or interfaces will act as defect sinks that could influence carrier dynamics in perovskite-based solar cells and electrical devices.

Original languageEnglish
Pages (from-to)356-360
Number of pages5
JournalACS Energy Letters
Issue number1
StatePublished - 13 Jan 2023


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