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Title: Influence of defects and dopants on the photovoltaic performance of Bi 2S 3: First-principles insights

Bi 2S 3 has attracted extensive attention recently as a light-absorber, sensitizer or electron acceptor material in various solar cells. Using first-principles calculations, we find that the photovoltaic efficiency of Bi 2S 3 solar cells is limited by its intrinsic point defects, i.e., both S vacancy and S interstitial can have high concentration and produce deep defect levels in the bandgap, leading to non-radiative recombination of electron–hole carriers and reduced minority carrier lifetime. Unexpectedly most of the intrinsic defects in Bi 2S 3, including even the S interstitial, act as donor defects, explaining the observed n-type conductivity and also causing the high p-type conductivity impossible thermodynamically. Doping in Bi 2S 3 by a series of extrinsic elements is studied, showing that most of the dopant elements such as Cu, Br and Cl make the material even more n-type and only Pb doping makes it weakly p-type. Based on this, we propose that the surface region of n-type Bi 2S 3 nanocrystals in p-PbS/n-Bi 2S 3 nano-heterojunction solar cells may be type-inverted into p-type due to Pb doping, with a buried p–n junction formed in the Bi 2S 3 nanocrystals, which provides a new explanation to the longer carrier lifetime andmore » higher efficiency. Lastly, considering the relatively low conduction band and high n-type conductivity, we predict that Cu, Br and Cl doped Bi 2S 3 may be an ideal n-type electron acceptor or counter electrode material, while the performance of Bi 2S 3 as a light-absorber or sensitizer material is intrinsically limited.« less
Authors:
ORCiD logo [1] ; ORCiD logo [2] ; ORCiD logo [1] ; ORCiD logo [1] ; ORCiD logo [3]
  1. East China Normal Univ., Shanghai (China)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  3. East China Normal Univ., Shanghai (China); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Journal of Materials Chemistry. A
Additional Journal Information:
Journal Volume: 5; Journal Issue: 13; Journal ID: ISSN 2050-7488
Publisher:
Royal Society of Chemistry
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE
OSTI Identifier:
1351779

Han, Dan, Du, Mao -Hua, Dai, Chen -Min, Sun, Deyan, and Chen, Shiyou. Influence of defects and dopants on the photovoltaic performance of Bi2S3: First-principles insights. United States: N. p., Web. doi:10.1039/C6TA10377D.
Han, Dan, Du, Mao -Hua, Dai, Chen -Min, Sun, Deyan, & Chen, Shiyou. Influence of defects and dopants on the photovoltaic performance of Bi2S3: First-principles insights. United States. doi:10.1039/C6TA10377D.
Han, Dan, Du, Mao -Hua, Dai, Chen -Min, Sun, Deyan, and Chen, Shiyou. 2017. "Influence of defects and dopants on the photovoltaic performance of Bi2S3: First-principles insights". United States. doi:10.1039/C6TA10377D. https://www.osti.gov/servlets/purl/1351779.
@article{osti_1351779,
title = {Influence of defects and dopants on the photovoltaic performance of Bi2S3: First-principles insights},
author = {Han, Dan and Du, Mao -Hua and Dai, Chen -Min and Sun, Deyan and Chen, Shiyou},
abstractNote = {Bi2S3 has attracted extensive attention recently as a light-absorber, sensitizer or electron acceptor material in various solar cells. Using first-principles calculations, we find that the photovoltaic efficiency of Bi2S3 solar cells is limited by its intrinsic point defects, i.e., both S vacancy and S interstitial can have high concentration and produce deep defect levels in the bandgap, leading to non-radiative recombination of electron–hole carriers and reduced minority carrier lifetime. Unexpectedly most of the intrinsic defects in Bi2S3, including even the S interstitial, act as donor defects, explaining the observed n-type conductivity and also causing the high p-type conductivity impossible thermodynamically. Doping in Bi2S3 by a series of extrinsic elements is studied, showing that most of the dopant elements such as Cu, Br and Cl make the material even more n-type and only Pb doping makes it weakly p-type. Based on this, we propose that the surface region of n-type Bi2S3 nanocrystals in p-PbS/n-Bi2S3 nano-heterojunction solar cells may be type-inverted into p-type due to Pb doping, with a buried p–n junction formed in the Bi2S3 nanocrystals, which provides a new explanation to the longer carrier lifetime and higher efficiency. Lastly, considering the relatively low conduction band and high n-type conductivity, we predict that Cu, Br and Cl doped Bi2S3 may be an ideal n-type electron acceptor or counter electrode material, while the performance of Bi2S3 as a light-absorber or sensitizer material is intrinsically limited.},
doi = {10.1039/C6TA10377D},
journal = {Journal of Materials Chemistry. A},
number = 13,
volume = 5,
place = {United States},
year = {2017},
month = {2}
}

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