Chloride Treatments Improve Zinc Telluride Absorbers for Photoelectrochemical Carbon Dioxide Reduction
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1.
National Renewable Energy Laboratory
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2.
California Institute of Technology
Abstract
Utilizing sunlight for photoelectrochemical carbon dioxide reduction reaction (PEC CO2 RR) is a carbon-neutral path to valuable liquid fuels. Higher quality photoabsorbers are needed to improve the efficiency of the PEC CO2 RR process. We show how the optoelectronic properties of sputtered ZnTe absorbers can be improved for this purpose via chloride treatments. MnCl2 and MgCl2 heat treatments recrystallize ZnTe absorbers to enlarge grains and improve photoluminescence. These material improvements result in the highest PEC CO2 RR photocurrent density reported for planar ZnTe and >50% Faradaic efficiency to CO formation with diaryliodonium additive in the solution. These results pave the way to integration of polycrystalline thin-film photoabsorbers in PEC CO2 RR systems.
Copyright and License
© 2025 The Authors. Published by American Chemical Society.
This publication is licensed under CC-BY 4.0.
Acknowledgement
This work was authored in part by the National Renewable Energy Laboratory, operated by Alliance for Sustainable Energy, LLC, for the U.S. Department of Energy (DOE) under contract No. DE-AC36-08GO28308. Funding provided by the Liquid Sunlight Alliance, which is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Fuels from Sunlight Hub, under award number DE-SC0021266. The authors gratefully acknowledge Sage Bauers, Deborah McGott, Shaham Quadir, Joel Duenow, Eric Colegrove, Matt Reese, Robert Morrissey, Steve Glynn, Steven Hayden, Patrick Walker, and Kevin Kan for help with experiments. We also acknowledge Nicholas B. Watkins for the preparation of additives used in this work. The views expressed in the article do not necessarily represent the views of the DOE or the U.S. Government.
Supplemental Material
Additional materials including XRF data for all samples, XRF data for different H2O levels, PL data for new and old chloride sources, XRD data on a logarithmic scale for all samples, UV/visible spectroscopy data for all samples, TRPL data for all samples, quantitative PL and TRPL data for all samples, PEC current density voltage data for all samples, photograph of all samples post-PEC run, CV scans for the bare substrates, ICP–MS data for all samples, PL uniformity data for all samples, Faradaic efficiency and current density data for all samples, and summary of ZnTe PEC CO2 RR literature results (PDF).
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Additional details
- United States Department of Energy
- DE-AC36-08GO28308
- United States Department of Energy
- DE-SC0021266
- Accepted
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2025-01-02Accepted
- Available
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2025-01-07Published
- Caltech groups
- Liquid Sunlight Alliance
- Publication Status
- Published