Aron Walsh1
Imperial College London1
The deeper you stare at metal halide perovskites, the more imperfections you become aware of. Dilute point defects, such as charged vacancies and interstitials, exist in a diverse landscape of extended defects including dislocations, stacking faults, and grain boundaries. To make matters worse, there are often chemical gradients in the A, B or X crystallographic positions, e.g. in mixed formamidinium/methylammonium, tin/lead, or iodide/bromide systems. I will discuss our growing understanding of these phenomena at the atomic scale drawing from our work from materials modelling [1,2] and linked to multi-modal characterisation [3,4]. The use of defect tolerance as a metric to develop and screen (post) perovskite materials will be critically addressed. This research is part of a Leverhulme Trust funded collaboration with the group of Sam Stranks and used the UK National Supercomputer ARCHER2 which is supported by UKRI.<br/><br/>1. Evolutionary exploration of polytypism in lead halide perovskites, Chemical Science 12, 12165 (2021)<br/>2. Giant Huang−Rhys factor for electron capture by the iodine interstitial in perovskite solar cells, Journal of the American Chemical Society 143, 9123 (2021)<br/>3. Performance-limiting nanoscale trap clusters at grain junctions in halide perovskites, Nature 580, 360 (2020)<br/>4. Stabilized tilted-octahedra halide perovskites inhibit local formation of performance-limiting phases, Science 374, 1598 (2021)