Correlated Anharmonicity and Dynamic Disorder Control Carrier Transport in Halide Perovskites

TL;DR

This paper explores how vibrational anharmonicity and dynamic disorder influence carrier transport in halide perovskites, revealing microscopic links that explain temperature-dependent mobility differences and guiding material optimization.

Contribution

It introduces a multi-scale model connecting lattice anharmonicity and dynamic disorder to electronic transport, providing new insights into structure-property relationships in halide perovskites.

Findings

Non-Gaussian lattice motion relates to dynamic disorder in electronic states.

Temperature-dependent mobilities differ across phase transitions in MAPbI3 and MAPbBr3.

Vibrational anharmonicity and dynamic disorder can predict electronic conductivity.

Abstract

Halide pervoskites are an important class of semiconducting materials which hold great promise for optoelectronic applications. In this work we investigate the relationship between vibrational anharmonicity and dynamic disorder in this class of solids. Via a multi-scale model parameterized from first-principles calculations, we demonstrate that the non-Gaussian lattice motion in halide perovskites is microscopically connected to the dynamic disorder of overlap fluctuations among electronic states. This connection allows us to rationalize the emergent differences in temperature-dependent mobilities of prototypical MAPbI$_3$ and MAPbBr$_3$ compounds across structural phase-transitions, in agreement with experimental findings. Our analysis suggests that the details of vibrational anharmonicity and dynamic disorder can complement known predictors of electronic conductivity and can provide structure-property guidelines for the tuning of carrier transport characteristics in anharmonic semiconductors.