Improvement in the optoelectronic performance of halide perovskite semiconductors requires the identification and suppression of nonradiative carrier trapping processes. The iodine interstitial has been established as a deep level defect and implicated as an active recombination center. We analyze the quantum mechanics of carrier trapping. Fast and irreversible electron capture by the neutral iodine interstitial is found. The effective Huang-Rhys factor exceeds 300, indicative of the strong electron-phonon coupling that is possible in soft semiconductors. The accepting phonon mode has a frequency of 53 cm-1 and has an associated electron capture coefficient of 1 × 10-10 cm3 s-1. The inverse participation ratio is used to quantify the localization of phonon modes associated with the transition. We infer that suppression of octahedral rotations is an important factor to enhance defect tolerance.
Bibliographical noteFunding Information:
Calculations were performed on the Oswald supercomputer at Northumbria University and the Piz Daint supercomputer at the Swiss National Supercomputing Centre (CSCS) via the Partnership for Advanced Computing in Europe (PRACE) project pr51. Via our membership of the UK’s HPC Materials Chemistry Consortium, which is funded by EPSRC (EP/L000202, EP/R029431), this work also used the ARCHER Supercomputing Service ( http://www.archer.ac.uk ). This work was supported by a National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (No. 2018R1C1B6008728) and the H2020 Programme under the project STARCELL (H2020-NMBP-03-2016-720907). J.M.F. is supported by a Royal Society University Research Fellowship (URF-R1-191292).
© 2021 The Authors. Published by American Chemical Society.
All Science Journal Classification (ASJC) codes
- Colloid and Surface Chemistry