Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published October 2014 | Published + Supplemental Material
Journal Article Open

Stabilization of n-cadmium telluride photoanodes for water oxidation to O_2(g) in aqueous alkaline electrolytes using amorphous TiO_2 films formed by atomic-layer deposition

Abstract

Although II–VI semiconductors such as CdS, CdTe, CdSe, ZnTe, and alloys thereof can have nearly ideal band gaps and band-edge positions for the production of solar fuels, II–VI photoanodes are well-known to be unstable towards photocorrosion or photopassivation when in contact with aqueous electrolytes. Atomic-layer deposition (ALD) of amorphous, "leaky" TiO_2 films coated with thin films or islands of Ni oxide has been shown to robustly protect Si, GaAs, and other III–V materials from photocorrosion and therefore to facilitate the robust, solar-driven photoelectrochemical oxidation of H_2O to O_2(g). We demonstrate herein that ALD-deposited 140 nm thick amorphous TiO_2 films also effectively protect single crystalline n-CdTe photoanodes from corrosion or passivation. An n-CdTe/TiO_2 electrode with a thin overlayer of a Ni-oxide based oxygen-evolution electrocatalyst produced 435 ± 15 mV of photovoltage with a light-limited current density of 21 ± 1 mA cm^−2 under 100 mW cm^−2 of simulated Air Mass 1.5 illumination. The ALD-deposited TiO_2 films are highly optically transparent and electrically conductive. We show that an n-CdTe/TiO_2/Ni oxide electrode enables the stable solar-driven oxidation of H_2O to O_2(g) in strongly alkaline aqueous solutions, where passive, intrinsically safe, efficient systems for solar-driven water splitting can be operated.

Additional Information

© 2014 Royal Society of Chemistry. Received 20th June 2014; accepted 21st August 2014. First published online 22 Aug 2014. This material is based upon work performed by the Joint Center for Artificial Photosynthesis, a DOE Energy Innovation Hub, supported through the Office of Science of the U. S. Department of Energy under Award Number DE-SC0004993. The authors gratefully acknowledge Dr Ke Sun for insightful discussions and Dr Slobodan Mitrovic for assistance collecting XPS data. AIC is grateful to the National Science Foundation for support from an NSF Graduate Research Fellowship. BSB and HBG acknowledge the Beckman Institute Materials and Laser Resource Centers and NSF CHE-1305124 for support.

Attached Files

Published - c4ee01914h.pdf

Supplemental Material - c4ee01914h1.pdf

Files

c4ee01914h.pdf
Files (1.0 MB)
Name Size Download all
md5:65c214fe408c8e755c8df1602e0f8632
403.7 kB Preview Download
md5:fe97723cafa8918665d79fdaa4d3174b
632.2 kB Preview Download

Additional details

Created:
August 20, 2023
Modified:
October 17, 2023