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Solution phase treatments of Sb$_2$Se$_3$ heterojunction photocathodes for improved water splitting performance


Adams, Pardis; Creazzo, Fabrizio; Moehl, Thomas; Crockett, Rowena; Zeng, Peng; Novotny, Zbynek; Luber, Sandra; Yang, Wooseok; Tilley, S David (2023). Solution phase treatments of Sb$_2$Se$_3$ heterojunction photocathodes for improved water splitting performance. Journal of Materials Chemistry A, 11(15):8277-8284.

Abstract

Antimony selenide (Sb$_2$Se$_3$) is an auspicious material for solar energy conversion that has seen rapid improvement over the past ten years, but the photovoltage deficit remains a challenge. Here, simple and low-temperature treatments of the p–n heterojunction interface of Sb$_2$Se$_3$/TiO$_2$-based photocathodes for photoelectrochemical water splitting were explored to address this challenge. The FTO/Ti/Au/Sb$_2$Se$_3$ (substrate configuration) stack was treated with (NH$_4$)$_2$S as an etching solution, followed by CuCl$_2$ treatment prior to deposition of the TiO$_2$ by atomic layer deposition. The different treatments show different mechanisms of action compared to similar reported treatments of the back Au/Sb$_2$Se$_3$ interface in superstrate configuration solar cells. These treatments collectively increased the onset potential from 0.14 V to 0.28 V vs. reversible hydrogen electrode (RHE) and the photocurrent from 13 mA cm$^{−2}$ to 18 mA cm$^{−2}$ at 0 V vs. RHE as compared to the untreated Sb$_2$Se$_3$ films. From SEM and XPS studies, it is clear that the etching treatment induces a morphological change and removes the surface Sb$_2$Se$_3$ layer, which eliminates the Fermi-level pinning that the oxide layer generates. CuCl$_2$ further enhances the performance due to the passivation of the surface defects, as supported by density functional theory molecular dynamics (DFT-MD) calculations, improving charge separation at the interface. The simple and low-cost semiconductor synthesis method combined with these facile, low-temperature treatments further increases the practical potential of Sb$_2$Se$_3$ for large-scale water splitting.

Abstract

Antimony selenide (Sb$_2$Se$_3$) is an auspicious material for solar energy conversion that has seen rapid improvement over the past ten years, but the photovoltage deficit remains a challenge. Here, simple and low-temperature treatments of the p–n heterojunction interface of Sb$_2$Se$_3$/TiO$_2$-based photocathodes for photoelectrochemical water splitting were explored to address this challenge. The FTO/Ti/Au/Sb$_2$Se$_3$ (substrate configuration) stack was treated with (NH$_4$)$_2$S as an etching solution, followed by CuCl$_2$ treatment prior to deposition of the TiO$_2$ by atomic layer deposition. The different treatments show different mechanisms of action compared to similar reported treatments of the back Au/Sb$_2$Se$_3$ interface in superstrate configuration solar cells. These treatments collectively increased the onset potential from 0.14 V to 0.28 V vs. reversible hydrogen electrode (RHE) and the photocurrent from 13 mA cm$^{−2}$ to 18 mA cm$^{−2}$ at 0 V vs. RHE as compared to the untreated Sb$_2$Se$_3$ films. From SEM and XPS studies, it is clear that the etching treatment induces a morphological change and removes the surface Sb$_2$Se$_3$ layer, which eliminates the Fermi-level pinning that the oxide layer generates. CuCl$_2$ further enhances the performance due to the passivation of the surface defects, as supported by density functional theory molecular dynamics (DFT-MD) calculations, improving charge separation at the interface. The simple and low-cost semiconductor synthesis method combined with these facile, low-temperature treatments further increases the practical potential of Sb$_2$Se$_3$ for large-scale water splitting.

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Other titles:Solution phase treatments of Sb2Se3 heterojunction photocathodes for improved water splitting performance
Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Department of Chemistry
07 Faculty of Science > Physics Institute
08 Research Priority Programs > Solar Light to Chemical Energy Conversion
Dewey Decimal Classification:540 Chemistry
Scopus Subject Areas:Physical Sciences > General Chemistry
Physical Sciences > Renewable Energy, Sustainability and the Environment
Physical Sciences > General Materials Science
Uncontrolled Keywords:General Materials Science, Renewable Energy, Sustainability and the Environment, General Chemistry
Language:English
Date:21 March 2023
Deposited On:20 Feb 2024 08:39
Last Modified:31 Mar 2024 01:36
Publisher:Royal Society of Chemistry
ISSN:2050-7488
OA Status:Hybrid
Publisher DOI:https://doi.org/10.1039/d3ta00554b
PubMed ID:37066134
Project Information:
  • : FunderSNSF
  • : Grant ID184737
  • : Project TitlePhotoelectrochemical Synthesis of Hydrogen and Value-Added Chemicals for a Sustainable Chemical Industry
  • Content: Published Version
  • Language: English
  • Licence: Creative Commons: Attribution 4.0 International (CC BY 4.0)