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The Interplay Between Lead Vacancy and Water Rationalizes the Puzzle of Charge Carrier Lifetimes in CH 3 NH 3 PbI 3 : Time‐Domain Ab Initio Analysis
Author(s) -
Qiao Lu,
Fang WeiHai,
Long Run
Publication year - 2020
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202004192
Subject(s) - vacancy defect , ab initio , excited state , chemical physics , electron , chemistry , ab initio quantum chemistry methods , recombination , molecule , perovskite (structure) , atomic physics , molecular physics , crystallography , physics , biochemistry , organic chemistry , quantum mechanics , gene
The perovskite CH 3 NH 3 PbI 3 excited‐state lifetimes exhibit conflicting experimental results under humid environments. Using ab initio nonadiabatic (NA) molecular dynamics, we demonstrate that the interplay between lead vacancy and water can rationalize the puzzle. The lead vacancy reduces NA coupling by localizing holes, slowing electron–hole recombination. By creating a deep electron trap state, the coexistence of a neutral lead vacancy and water molecules enhances NA coupling, accelerating charge recombination by a factor of over 3. By eliminating the mid‐gap state by accepting two photoexcited electrons, the negatively charged lead vacancy interacting with water molecules increases the carrier lifetime over 2 times longer than in the pristine system. The simulations rationalize the positive and negative effects of water on the solar cell performance exposure to humidity.