Structure and interstitial iodide migration in hybrid perovskite methylammonium lead iodide.

ABSTRACT: Hybrid perovskites form an emerging family of exceptional light harvesting compounds. However, the mechanism underpinning their photovoltaic effect is still far from understood, which is impeded by a lack of clarity on their structures. Here we show that iodide ions in the methylammonium lead iodide migrate via interstitial sites at temperatures above 280 K. This coincides with temperature dependent static distortions resulting in pseudocubic local symmetry. Based on bond distance analysis, the migrating and distorted iodines are at lengths consistent with the formation of I₂ molecules, suggesting a 2I^-→I₂+2e^- redox couple. The actual formula of this compound is thus (CH₃NH₃)PbI_3-2x(I₂)_x wher

SUBMITTER: Minns JL 

PROVIDER: S-EPMC5437276 | biostudies-literature | 2017 May

REPOSITORIES: biostudies-literature