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Improved current collection in WO3:Mo/WO3 bilayer photoelectrodes

Published online by Cambridge University Press:  31 January 2011

Eric L. Miller*
Affiliation:
Hawaii Natural Energy Institute, University of Hawaii at Manoa, Honolulu, Hawaii 96822
Bjorn Marsen
Affiliation:
Solar Energy Research, Helmholtz-Zentrum Berlin für Materialien und Energie, Lise-Meitner-Campus, D-14109 Berlin, Germany
Lothar Weinhardt
Affiliation:
Department of Chemistry, University of Nevada, Las Vegas, Nevada 89154-4003; and Experimentelle Physik II, Universität Würzburg, D-97074 Würzburg, Germany
Marcus Bär
Affiliation:
Solar Energy Research, Helmholtz-Zentrum Berlin für Materialien und Energie, Lise-Meitner-Campus, D-14109 Berlin, Germany; and Department of Chemistry, University of Nevada, Las Vegas, Nevada 89154-4003
Clemens Heske
Affiliation:
Department of Chemistry, University of Nevada, Las Vegas, Nevada 89154-4003
Mowafak M. Al-Jassim
Affiliation:
National Renewable Energy Laboratory, Golden, Colorado 80401
*
b)This author was an editor of this focus issue during the review and decision stage. For the JMR policy on review and publication of manuscripts authored by editors, please refer to http://www.mrs.org/jmr_policy
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Abstract

We report on the incorporation of molybdenum into tungsten oxide by co-sputtering and its effect on solar-powered photoelectrochemical (PEC) water splitting. Our study shows that Mo incorporation in the bulk of the film (WO3:Mo) results in poor PEC performance when compared with pure WO3, most likely due to defects that trap photo-generated charge carriers. However, when a WO3:Mo/WO3 bilayer electrode is used, a 20% increase of the photocurrent density at 1.6 V versus saturated calomel reference electrode is observed compared with pure WO3. Morphological and microstructural analysis of the WO3:Mo/WO3 bilayer structure reveals that it is formed by coherent growth of the WO3:Mo top layer on the WO3 bottom layer. This effect allows an optimization of the electronic surface structure of the electrode while maintaining good crystallographic properties in the bulk.

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Articles
Copyright
Copyright © Materials Research Society 2010

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References

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