Comprehensive Evaluation for Protective Coatings: Optical, Electrical, Photoelectrochemical, and Spectroscopic Characterizations
Abstract
Numerous efficient semiconductors suffer from instability in aqueous electrolytes. Strategies utilizing protective coatings have thus been developed to protect these photoabsorbers against corrosion while synergistically improving charge separation and reaction kinetics. Recently, various photoelectrochemical (PEC) protective coatings have been reported with suitable electronic properties to ensure low charge transport loss and reveal the fundamental photoabsorber efficiency. However, protocols for studying the critical figures of merit for protective coatings have yet to be established. For this reason, we propose four criteria for evaluating the performance of a protective coating for PEC water-splitting: stability, conductivity, optical transparency, and energetic matching. We then propose a flow chart that summarizes the recommended testing protocols for quantifying these four performance metrics. In particular, we lay out the stepwise testing protocols to evaluate the energetics matching at a semiconductor/coating/(catalyst)/liquid interface. Finally, we provide an outlook for the future benchmarking needs for coatings.
Additional Information
© 2022 Shen, Yanagi, Solanki, Su, Li, Xiang and Hu. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. Received: 22 October 2021; Accepted: 17 December 2021; Published: 12 January 2022. SH gratefully acknowledges the financial support of the National Science Foundation Award No. CBET-2055416. C-XX gratefully acknowledges the support from the Fuel Cell Technologies Office, of the United States Department of Energy, Energy Efficiency and Renewable Energy (EERE) under contract number DE-EE0008092. RY acknowledges fellowship support from Japan Student Services Organization. Author Contributions. C-XX and SH conceived the idea and designed this review. XS collected and reviewed the related literatures. XS and RY designed and made the schematics and figures with help from DS and HS. XS and DS wrote the manuscript. XS revised the manuscript with help from SH, CX and DS. SH revised the manuscript and oversaw the project. All authors contributed to the manuscript and provided feedback. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.Attached Files
Published - fenrg-09-799776.pdf
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Additional details
- Eprint ID
- 113830
- Resolver ID
- CaltechAUTHORS:20220309-676764000
- CBET-2055416
- NSF
- DE-EE0008092
- Department of Energy (DOE)
- Japan Student Services Organization (JASSO)
- Created
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2022-03-10Created from EPrint's datestamp field
- Updated
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2022-05-10Created from EPrint's last_modified field