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arXiv · 2211.00956

Inhomogeneous Defect Distribution in Mixed-Polytype Metal Halide Perovskites

Young Won Woo·Zhenzhu Li·Young-Kwang Jung·Ji-Sang Park·Aron Walsh
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Abstract

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 CsPbI$_3$ from first-principles materials modelling. 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 trap charges and enhance current-voltage hysteresis in perovskite-based solar cells and electrical devices.

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Young Won Woo, Zhenzhu Li, Young-Kwang Jung, Ji-Sang Park, Aron Walsh. 2022-11-02. Inhomogeneous Defect Distribution in Mixed-Polytype Metal Halide Perovskites. https://arxiv.org/abs/2211.00956

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