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Title: Role of Lead Vacancies for Optoelectronic Properties of Lead-Halide Perovskites

Abstract

Methylammonium lead iodide perovskite materials have been shown to be efficient in photovoltaic devices. The current fabrication process has not been perfected, leaving defects such as site vacancies, which can trap charge and have a detrimental effect on photogenerated charge carriers. Here focus is placed on the effect a Pb site vacancy has on the charge-carrier dynamics following photoexcitation. The electronic structure of materials with vacancies is often found in open-shell configurations with unpaired electrons in the conduction/valence bands To accurately describe unpaired electrons, spin-polarized and noncollinear spin calculations are performed on both neutral and charged vacancy systems. This work presents spin-polarized and noncollinear spin ground-state electronic structures and nonradiative rates of charge-carrier relaxation and introduces an extension to a novel procedure to compute photoluminescence spectra for open-shell models. This study describes nonadiabatic dynamics of MAPbI3 models within a Redfield formalism focusing on the role of a Pb vacancy defect on electronic relaxation processes. Results show the vacancy of the Pb ion introducing a new energy state within the unblemished material band gap region. Finally, this additional unoccupied state is expected to increase the nonradiative relaxation lifetime of the excited electron, allowing for a longer lifetime of the charge carriermore » and increased opportunity for secondary relaxation mechanisms or collection to take place.« less

Authors:
 [1];  [2];  [3]
  1. Univ. of South Dakota, Vermillion, SD (United States). Dept. of Chemistry
  2. L.N. Gumilyov Eurasian National Univ., Astana (Kazakhstan); National Univ. of Science and Technology, Moscow (Russia)
  3. Univ. of South Dakota, Vermillion, SD (United States). Dept. of Chemistry; North Dakota State Univ., Fargo, ND (United States). Dept. of Chemistry and Biochemistry
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
OSTI Identifier:
1480500
Grant/Contract Number:  
AC02-05CH11231
Resource Type:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. C
Additional Journal Information:
Journal Volume: 122; Journal Issue: 10; Journal ID: ISSN 1932-7447
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Vogel, Dayton J., Inerbaev, Talgat M., and Kilin, Dmitri S. Role of Lead Vacancies for Optoelectronic Properties of Lead-Halide Perovskites. United States: N. p., 2017. Web. doi:10.1021/acs.jpcc.7b05375.
Vogel, Dayton J., Inerbaev, Talgat M., & Kilin, Dmitri S. Role of Lead Vacancies for Optoelectronic Properties of Lead-Halide Perovskites. United States. doi:10.1021/acs.jpcc.7b05375.
Vogel, Dayton J., Inerbaev, Talgat M., and Kilin, Dmitri S. Mon . "Role of Lead Vacancies for Optoelectronic Properties of Lead-Halide Perovskites". United States. doi:10.1021/acs.jpcc.7b05375. https://www.osti.gov/servlets/purl/1480500.
@article{osti_1480500,
title = {Role of Lead Vacancies for Optoelectronic Properties of Lead-Halide Perovskites},
author = {Vogel, Dayton J. and Inerbaev, Talgat M. and Kilin, Dmitri S.},
abstractNote = {Methylammonium lead iodide perovskite materials have been shown to be efficient in photovoltaic devices. The current fabrication process has not been perfected, leaving defects such as site vacancies, which can trap charge and have a detrimental effect on photogenerated charge carriers. Here focus is placed on the effect a Pb site vacancy has on the charge-carrier dynamics following photoexcitation. The electronic structure of materials with vacancies is often found in open-shell configurations with unpaired electrons in the conduction/valence bands To accurately describe unpaired electrons, spin-polarized and noncollinear spin calculations are performed on both neutral and charged vacancy systems. This work presents spin-polarized and noncollinear spin ground-state electronic structures and nonradiative rates of charge-carrier relaxation and introduces an extension to a novel procedure to compute photoluminescence spectra for open-shell models. This study describes nonadiabatic dynamics of MAPbI3 models within a Redfield formalism focusing on the role of a Pb vacancy defect on electronic relaxation processes. Results show the vacancy of the Pb ion introducing a new energy state within the unblemished material band gap region. Finally, this additional unoccupied state is expected to increase the nonradiative relaxation lifetime of the excited electron, allowing for a longer lifetime of the charge carrier and increased opportunity for secondary relaxation mechanisms or collection to take place.},
doi = {10.1021/acs.jpcc.7b05375},
journal = {Journal of Physical Chemistry. C},
number = 10,
volume = 122,
place = {United States},
year = {2017},
month = {12}
}

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Cited by: 10 works
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Figures / Tables:

Figure 1 Figure 1: Model of 3x3x3 cubic MAPbI3 perovskite with central Pb-vacancy (Vac). Anionic configuration facilitates formation of quasistable I2 molecules at the place of Pb vacancy. Formation of the I2 molecule can be quantitatively monitored via decrease of I-I bond length and increment of the Pb-I bondlength (dashes). The modelmore » under study shows the location of the Pb vacancy as a 2D slice (A), 3D model (B), and an example of band structure (C) which shows negligible dispersion of defect state, see Fig. S3 for details.« less

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Figures/Tables have been extracted from DOE-funded journal article accepted manuscripts.