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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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 |
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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 |
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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. |
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School of Materials Science and Engineering |
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School of Materials Science and Engineering Tay, Ying Fan Hadke, Shreyash Sudhakar Zhang, Mengyuan Lim, Nathan Chiam, Sing Yang Wong, Lydia Helena |
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Article |
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Tay, Ying Fan Hadke, Shreyash Sudhakar Zhang, Mengyuan Lim, Nathan Chiam, Sing Yang Wong, Lydia Helena |
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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 |
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2020 |
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https://hdl.handle.net/10356/143982 https://doi.org/10.21979/N9/5K3QE4 |
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1773551335465025536 |