2019/01/03 by Andrew R. Warwick, Jorge Íñiguez, Peter D. Haynes +1 · 1 citation
Physics and Astronomy · #cond-mat.mtrl-sci
paper · pdf · doi:10.1021/acs.jpclett.9b00202
arxiv created 2019/01/03 · arxiv updated 2019/03/14
We present an ab initio simulation of 90∘ ferroelastic twins that were recently observed in methyl ammonium lead iodide. There are two inequivalent types of 90∘ walls that we calculate to act as either electron or hole sinks which suggests a possible route to enhancing charge carrier separation in photovoltaic devices. Despite separating non-polar domains, we show these walls to have a substantial in-plane polarisation of ∼ 6 \phantom| μC\phantom|cm-2, due in part to flexoelectricity. We suggest this in turn could allow for the photoferroic effect and create efficient pathways for photocurrents within the wall.