Issue 10, 2024

Efficient hydrogen evolution from water over a thin film photocathode composed of solid solutions with a composition gradient of ZnTe and CdTe

Abstract

Photoelectrodes utilising cadmium telluride (CdTe) have shown promising properties as photocathodes for solar hydrogen evolution from water, such as a large cathodic photocurrent, owing to their long optical absorption edge of about 840 nm, and a large driving force for the reaction according to a flat band potential of close to 0.9 VRHE. However, their performance is limited, especially in a relatively high potential region. For the fabrication of a practical photoelectrochemical device, photocathodes with sufficiently high onset potential and high photocurrent at around 0.6 VRHE are desired. In this study, a thin film CdTe based photocathode composed of a bilayer structure with zinc telluride (ZnTe) as the back contact was successfully fabricated by sequential deposition of ZnTe and CdTe using the close space sublimation method. The addition of a small amount of Cu is essential to obtain an efficient photocathode and, interestingly, a composition gradient is introduced through the formation of a solid solution at the ZnTe–CdTe interface. Post-deposition rapid thermal annealing further enhanced the cathodic photocurrent resulting in 4.0 mA cm−2 at 0.5 VRHE and a half-cell solar-to-hydrogen conversion efficiency of 3.6% at 0.36 VRHE with incident photon-to-current conversion efficiencies of >70% at 480–640 nm.

Graphical abstract: Efficient hydrogen evolution from water over a thin film photocathode composed of solid solutions with a composition gradient of ZnTe and CdTe

Supplementary files

Article information

Article type
Paper
Submitted
13 Jan 2024
Accepted
04 Apr 2024
First published
05 Apr 2024
This article is Open Access
Creative Commons BY license

Sustainable Energy Fuels, 2024,8, 2210-2218

Efficient hydrogen evolution from water over a thin film photocathode composed of solid solutions with a composition gradient of ZnTe and CdTe

L. S. Veiga, H. Kumagai, M. Sugiyama and T. Minegishi, Sustainable Energy Fuels, 2024, 8, 2210 DOI: 10.1039/D4SE00067F

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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