Improving the interfacial properties of CZTS photocathodes by Ag substitution

Cu2ZnSnS4 (CZTS) is a promising photocathode in a water splitting system due to its appropriate conduction band position with the water reduction potential, suitable band gap and high absorption coefficient. However, CZTS has yet to demonstrate unbiased solar to hydrogen efficiency above 1% in a pho...

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Main Authors: Tay, Ying Fan, Hadke, Shreyash Sudhakar, Zhang, Mengyuan, Lim, Nathan, Chiam, Sing Yang, Wong, Lydia Helena
Other Authors: School of Materials Science and Engineering
Format: Article
Language:English
Published: 2020
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Online Access:https://hdl.handle.net/10356/143982
https://doi.org/10.21979/N9/5K3QE4
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spelling sg-ntu-dr.10356-1439822023-07-14T15:58:58Z Improving the interfacial properties of CZTS photocathodes by Ag substitution Tay, Ying Fan Hadke, Shreyash Sudhakar Zhang, Mengyuan Lim, Nathan Chiam, Sing Yang Wong, Lydia Helena School of Materials Science and Engineering Graduate Studies Office Institute of Materials Research and Engineering (IMRE) Energy Research Institute @ NTU (ERI@N) Engineering::Materials CZTS Photocathode Cu2ZnSnS4 (CZTS) is a promising photocathode in a water splitting system due to its appropriate conduction band position with the water reduction potential, suitable band gap and high absorption coefficient. However, CZTS has yet to demonstrate unbiased solar to hydrogen efficiency above 1% in a photocathode-photoanode tandem setup unlike its CuInGaSe2 chalcogenide counterpart due to its low onset potential and photocurrent. This low onset potential and photocurrent is believed to be limited by the large density of defects in CZTS and at the CZTS/CdS interface which limits the open-circuit voltage in CZTS solar cells. In this work (AgxCu1-x)2ZnSnS4 (ACZTS) with Ag+ partially replacing Cu+ is fabricated by solution process and investigated as a photocathode. Our ACZTS/CdS/Pt photocathode yields a maximum photocurrent of 17.7 mA cm-2 at 0 VRHE at 4% Ag (x = 0.04) and a maximum onset potential of 0.85 VRHE at 8% Ag (x = 0.08), which is a substantial improvement from our CZTS/CdS/Pt photocathode that has a photocurrent of 13 mA cm-2 and onset potential of 0.65 VRHE. A combination of incident photon to current efficiency (IPCE) measurements done in a photoelectrochemical (PEC) and photovoltaic (PV) setup attributes the improvement to the interface properties. Other PV measurements such as capacitance-voltage profiling (CV) and Mott-Schottky measurements reveal a lower apparent carrier concentration and higher built-in voltage of ACZTS. Ministry of Education (MOE) National Research Foundation (NRF) Accepted version This research is partially supported by grants from the National Research Foundation, Prime Minister’s Office, Singapore under its Campus of Research Excellence and Technological Enterprise (CREATE) programme and Ministry of Education (MOE) Tier 2 Project (MOE2016-T2-1-030) 2020-10-06T03:38:09Z 2020-10-06T03:38:09Z 2020 Journal Article Tay, Y. F., Hadke, S. S., Zhang, M., Lim, N., Chiam, S. Y., & Wong, L. H. (2020). Improving the interfacial properties of CZTS photocathodes by Ag substitution. Journal of Materials Chemistry A, 8(18), 8862-8867. doi:10.1039/D0TA02042G 2050-7496 https://hdl.handle.net/10356/143982 10.1039/D0TA02042G 18 8 8862 8867 en MOE2016-T2-1-030 Journal of Materials Chemistry A https://doi.org/10.21979/N9/5K3QE4 © 2020 Royal Society of Chemistry. All rights reserved. This paper was published in Journal of Materials Chemistry A and is made available with permission of Royal Society of Chemistry. application/pdf application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic Engineering::Materials
CZTS
Photocathode
spellingShingle Engineering::Materials
CZTS
Photocathode
Tay, Ying Fan
Hadke, Shreyash Sudhakar
Zhang, Mengyuan
Lim, Nathan
Chiam, Sing Yang
Wong, Lydia Helena
Improving the interfacial properties of CZTS photocathodes by Ag substitution
description Cu2ZnSnS4 (CZTS) is a promising photocathode in a water splitting system due to its appropriate conduction band position with the water reduction potential, suitable band gap and high absorption coefficient. However, CZTS has yet to demonstrate unbiased solar to hydrogen efficiency above 1% in a photocathode-photoanode tandem setup unlike its CuInGaSe2 chalcogenide counterpart due to its low onset potential and photocurrent. This low onset potential and photocurrent is believed to be limited by the large density of defects in CZTS and at the CZTS/CdS interface which limits the open-circuit voltage in CZTS solar cells. In this work (AgxCu1-x)2ZnSnS4 (ACZTS) with Ag+ partially replacing Cu+ is fabricated by solution process and investigated as a photocathode. Our ACZTS/CdS/Pt photocathode yields a maximum photocurrent of 17.7 mA cm-2 at 0 VRHE at 4% Ag (x = 0.04) and a maximum onset potential of 0.85 VRHE at 8% Ag (x = 0.08), which is a substantial improvement from our CZTS/CdS/Pt photocathode that has a photocurrent of 13 mA cm-2 and onset potential of 0.65 VRHE. A combination of incident photon to current efficiency (IPCE) measurements done in a photoelectrochemical (PEC) and photovoltaic (PV) setup attributes the improvement to the interface properties. Other PV measurements such as capacitance-voltage profiling (CV) and Mott-Schottky measurements reveal a lower apparent carrier concentration and higher built-in voltage of ACZTS.
author2 School of Materials Science and Engineering
author_facet School of Materials Science and Engineering
Tay, Ying Fan
Hadke, Shreyash Sudhakar
Zhang, Mengyuan
Lim, Nathan
Chiam, Sing Yang
Wong, Lydia Helena
format Article
author Tay, Ying Fan
Hadke, Shreyash Sudhakar
Zhang, Mengyuan
Lim, Nathan
Chiam, Sing Yang
Wong, Lydia Helena
author_sort Tay, Ying Fan
title Improving the interfacial properties of CZTS photocathodes by Ag substitution
title_short Improving the interfacial properties of CZTS photocathodes by Ag substitution
title_full Improving the interfacial properties of CZTS photocathodes by Ag substitution
title_fullStr Improving the interfacial properties of CZTS photocathodes by Ag substitution
title_full_unstemmed Improving the interfacial properties of CZTS photocathodes by Ag substitution
title_sort improving the interfacial properties of czts photocathodes by ag substitution
publishDate 2020
url https://hdl.handle.net/10356/143982
https://doi.org/10.21979/N9/5K3QE4
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