Density Functional Theory + U Modeling of Polarons in Organohalide Lead Perovskites
Date
2016-12
Authors
Welch, Eric
Scolfaro, Luisa M.
Zakhidov, Alex
Journal Title
Journal ISSN
Volume Title
Publisher
AIP Publishing
Abstract
We investigate the possible formation of polarons in four organic perovskites (CH3NH3PbI3, CH3NH3PbBr3, CH3NH3PbCl3, and CH3NH3PbI2Cl1) using a density functional theory (DFT) calculations with local potentials and hybrid functionals. We show that DFT+U method with U = 8 eV predicts a correct band-gap and matches the forces on ions from hybrid calculations. We then use the DFT + U approach to study the effect of polarons, i.e. to search the configuration space and locate the lowest energy localized band gap state self-trapped hole (STH). STH configurations were found for three pure halides and one mixed halide system. Spin orbit coupling (SOC) was also taken into account and the results may be found in the supplementary material. This study focuses on the +U method; however, SOC corrections added to the DFT+U calculations also resulted in STH states in all four systems.
Description
Keywords
polarons, organic perovskites, density functional theory, Physics
Citation
Welch, E., Scolfaro, L. M. & Zakhidov, A. (2016). Density functional theory + U modeling of polarons in organohalide lead perovskites. AIP Advances, 6, 125037.
Rights
Rights Holder
Rights License
This work is licensed under a Creative Commons Attribution 4.0 International License.