Predicting the thermodynamic stability of doubleperovskite halides from density functional theory
Recently, a series of doubleperovskite halide compounds such as Cs _{2}AgBiCl _{6} and Cs _{2}AgBiBr _{6} have attracted intensive interest as promising alternatives to the solar absorber material CH _{3}NH _{3}PbI _{3} because they are Pbfree and may exhibit enhanced stability. The thermodynamic stability of a number of doubleperovskite halides has been predicted based on density functional theory (DFT) calculations of compound formation energies. In this paper, we found that the stability prediction can be dependent on the approximations used for the exchangecorrelation functionals, e.g., the DFT calculations using the widely used Perdew, Burke, Ernzerhof (PBE) functional predict that Cs _{2}AgBiBr _{6} is thermodynamically unstable against phaseseparation into the competing phases such as AgBr, Cs _{2}AgBr _{3}, Cs _{3}Bi _{2}Br _{9}, etc., obviously inconsistent with the good stability observed experimentally. The incorrect prediction by the PBE calculation results from its failure to predict the correct groundstate structures of AgBr, AgCl, and CsCl. By contrast, the DFT calculations based on local density approximation, optB86bvdW, and optB88vdW functionals predict the groundstate structures of these binary halides correctly. Furthermore, the optB88vdW functional is found to give the most accurate description of the lattice constants of the doubleperovskite halides and their competing phases. Givenmore »
 Authors:

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 East China Normal Univ., Shanghai (China)
 Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
 East China Normal Univ., Shanghai (China); Shanxi Univ., Shanxi (China)
 Publication Date:
 Grant/Contract Number:
 AC0500OR22725
 Type:
 Accepted Manuscript
 Journal Name:
 APL Materials
 Additional Journal Information:
 Journal Volume: 6; Journal Issue: 8; Journal ID: ISSN 2166532X
 Publisher:
 American Institute of Physics (AIP)
 Research Org:
 Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
 Sponsoring Org:
 USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC22)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 36 MATERIALS SCIENCE
 OSTI Identifier:
 1440832
Han, Dan, Zhang, Tao, Huang, Menglin, Sun, Deyan, Du, Mao Hua, and Chen, Shiyou. Predicting the thermodynamic stability of doubleperovskite halides from density functional theory. United States: N. p.,
Web. doi:10.1063/1.5027414.
Han, Dan, Zhang, Tao, Huang, Menglin, Sun, Deyan, Du, Mao Hua, & Chen, Shiyou. Predicting the thermodynamic stability of doubleperovskite halides from density functional theory. United States. doi:10.1063/1.5027414.
Han, Dan, Zhang, Tao, Huang, Menglin, Sun, Deyan, Du, Mao Hua, and Chen, Shiyou. 2018.
"Predicting the thermodynamic stability of doubleperovskite halides from density functional theory". United States.
doi:10.1063/1.5027414. https://www.osti.gov/servlets/purl/1440832.
@article{osti_1440832,
title = {Predicting the thermodynamic stability of doubleperovskite halides from density functional theory},
author = {Han, Dan and Zhang, Tao and Huang, Menglin and Sun, Deyan and Du, Mao Hua and Chen, Shiyou},
abstractNote = {Recently, a series of doubleperovskite halide compounds such as Cs2AgBiCl6 and Cs2AgBiBr6 have attracted intensive interest as promising alternatives to the solar absorber material CH3NH3PbI3 because they are Pbfree and may exhibit enhanced stability. The thermodynamic stability of a number of doubleperovskite halides has been predicted based on density functional theory (DFT) calculations of compound formation energies. In this paper, we found that the stability prediction can be dependent on the approximations used for the exchangecorrelation functionals, e.g., the DFT calculations using the widely used Perdew, Burke, Ernzerhof (PBE) functional predict that Cs2AgBiBr6 is thermodynamically unstable against phaseseparation into the competing phases such as AgBr, Cs2AgBr3, Cs3Bi2Br9, etc., obviously inconsistent with the good stability observed experimentally. The incorrect prediction by the PBE calculation results from its failure to predict the correct groundstate structures of AgBr, AgCl, and CsCl. By contrast, the DFT calculations based on local density approximation, optB86bvdW, and optB88vdW functionals predict the groundstate structures of these binary halides correctly. Furthermore, the optB88vdW functional is found to give the most accurate description of the lattice constants of the doubleperovskite halides and their competing phases. Given these two aspects, we suggest that the optB88vdW functional should be used for predicting thermodynamic stability in the future highthroughput computational material design or the construction of the Materials Genome database for new doubleperovskite halides. As a result, using different exchangecorrelation functionals has little influence on the dispersion of the conduction and the valence bands near the electronic bandgap; however, the calculated bandgap can be affected indirectly by the optimized lattice constant, which varies for different functionals.},
doi = {10.1063/1.5027414},
journal = {APL Materials},
number = 8,
volume = 6,
place = {United States},
year = {2018},
month = {5}
}
Works referenced in this record:
AirStable Molecular Semiconducting Iodosalts for Solar Cell Applications: Cs_{2}SnI_{6} as a Hole Conductor
journal, October 2014
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 Journal of the American Chemical Society, Vol. 136, Issue 43, p. 1537915385