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Title: Employing overlayers to improve the performance of Cu 2BaSnS 4 thin film based photoelectrochemical water reduction devices

Abstract

Earth-abundant copper-barium-thiostannate Cu 2BaSnS 4 (CBTS)-based thin films have recently been reported to exhibit the optoelectronic and defect properties suitable as absorbers for photoelectrochemical (PEC) water splitting and the top cell of tandem photovoltaic solar cells. However, the photocurrents of CBTS-based PEC devices are still much lower than the theoretical value, partially due to ineffective charge collection at CBTS/water interface and instability of CBTS in electrolytes. Here, we report on overcoming these issues by employing overlayer engineering. We find that CdS/ZnO/TiO 2 overlayers can significant-ly improve the PEC performance, achieving saturated cathodic photocurrents up to 7.8 mA cm -2 at the potential of -0.10 V versus reversible hydrogen electrode (RHE) in a neutral electrolyte solution, which is much higher than the best bare CBTS film attaining a photocurrent of 4.8 mA cm -2 at the potential of -0.2 V versus RHE. Finally, our results suggest a viable approach for improving the performance of CBTS-based PEC cells.

Authors:
ORCiD logo [1];  [1];  [1];  [1];  [2];  [2];  [2];  [2];  [1];  [1]; ORCiD logo [1]
  1. The Univ. of Toledo, Toledo, OH (United States)
  2. National Renewable Energy Lab. (NREL), Golden, CO (United States)
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Workforce Development for Teachers and Scientists (WDTS) (SC-27); National Science Foundation (NSF)
OSTI Identifier:
1346536
Report Number(s):
NREL/JA-5900-67785
Journal ID: ISSN 0897-4756
Grant/Contract Number:
AC36-08GO28308; AC02-05CH11231; CHE-1230246; DMR-1534686
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Chemistry of Materials
Additional Journal Information:
Journal Volume: 29; Journal Issue: 3; Journal ID: ISSN 0897-4756
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
08 HYDROGEN; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; optoelectronics; absorbers; photoelectrochemical water splitting; overlayer engineering

Citation Formats

Ge, Jie, Roland, Paul J., Koirala, Prakash, Meng, Weiwei, Young, James L., Petersen, Reese, Deutsch, Todd G., Teeter, Glenn, Ellingson, Randy J., Collins, Robert W., and Yan, Yanfa. Employing overlayers to improve the performance of Cu2BaSnS4 thin film based photoelectrochemical water reduction devices. United States: N. p., 2017. Web. doi:10.1021/acs.chemmater.6b03347.
Ge, Jie, Roland, Paul J., Koirala, Prakash, Meng, Weiwei, Young, James L., Petersen, Reese, Deutsch, Todd G., Teeter, Glenn, Ellingson, Randy J., Collins, Robert W., & Yan, Yanfa. Employing overlayers to improve the performance of Cu2BaSnS4 thin film based photoelectrochemical water reduction devices. United States. doi:10.1021/acs.chemmater.6b03347.
Ge, Jie, Roland, Paul J., Koirala, Prakash, Meng, Weiwei, Young, James L., Petersen, Reese, Deutsch, Todd G., Teeter, Glenn, Ellingson, Randy J., Collins, Robert W., and Yan, Yanfa. Thu . "Employing overlayers to improve the performance of Cu2BaSnS4 thin film based photoelectrochemical water reduction devices". United States. doi:10.1021/acs.chemmater.6b03347. https://www.osti.gov/servlets/purl/1346536.
@article{osti_1346536,
title = {Employing overlayers to improve the performance of Cu2BaSnS4 thin film based photoelectrochemical water reduction devices},
author = {Ge, Jie and Roland, Paul J. and Koirala, Prakash and Meng, Weiwei and Young, James L. and Petersen, Reese and Deutsch, Todd G. and Teeter, Glenn and Ellingson, Randy J. and Collins, Robert W. and Yan, Yanfa},
abstractNote = {Earth-abundant copper-barium-thiostannate Cu2BaSnS4 (CBTS)-based thin films have recently been reported to exhibit the optoelectronic and defect properties suitable as absorbers for photoelectrochemical (PEC) water splitting and the top cell of tandem photovoltaic solar cells. However, the photocurrents of CBTS-based PEC devices are still much lower than the theoretical value, partially due to ineffective charge collection at CBTS/water interface and instability of CBTS in electrolytes. Here, we report on overcoming these issues by employing overlayer engineering. We find that CdS/ZnO/TiO2 overlayers can significant-ly improve the PEC performance, achieving saturated cathodic photocurrents up to 7.8 mA cm-2 at the potential of -0.10 V versus reversible hydrogen electrode (RHE) in a neutral electrolyte solution, which is much higher than the best bare CBTS film attaining a photocurrent of 4.8 mA cm-2 at the potential of -0.2 V versus RHE. Finally, our results suggest a viable approach for improving the performance of CBTS-based PEC cells.},
doi = {10.1021/acs.chemmater.6b03347},
journal = {Chemistry of Materials},
number = 3,
volume = 29,
place = {United States},
year = {Thu Jan 19 00:00:00 EST 2017},
month = {Thu Jan 19 00:00:00 EST 2017}
}

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Cited by: 6works
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  • We investigate point defects in the buffer layers CdS and ZnS that may arise from intermixing with Cu(In,Ga)(S,Se){sub 2} (CIGS) or Cu{sub 2}ZnSn(S,Se){sub 4} (CZTS) absorber layers in thin-film photovoltaics. Using hybrid functional calculations, we characterize the electrical and optical behavior of Cu, In, Ga, Se, Sn, Zn, Na, and K impurities in the buffer. We find that In and Ga substituted on the cation site act as shallow donors in CdS and tend to enhance the prevailing n-type conductivity at the interface facilitated by Cd incorporation in CIGS, whereas they are deep donors in ZnS and will be lessmore » effective dopants. Substitutional In and Ga can favorably form complexes with cation vacancies (A-centers) which may contribute to the “red kink” effect observed in some CIGS-based devices. For CZTS absorbers, we find that Zn and Sn defects substituting on the buffer cation site are electrically inactive in n-type buffers and will not supplement the donor doping at the interface as in CIGS/CdS or ZnS devices. Sn may also preferentially incorporate on the S site as a deep acceptor in n-type ZnS, which suggests possible concerns with absorber-related interfacial compensation in CZTS devices with ZnS-derived buffers. Cu, Na, and K impurities are found to all have the same qualitative behavior, most favorably acting as compensating acceptors when substituting on the cation site. Our results suggest one beneficial role of K and Na incorporation in CIGS or CZTS devices is the partial passivation of vacancy-related centers in CdS and ZnS buffers, rendering them less effective interfacial hole traps and recombination centers.« less
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