CVD-grown copper tungstate thin films for solar water splitting

Peeters, D. ¹Reyes, O. Mendoza ²Mai, L. ¹Sadlo, A. ¹Cwik, S. ¹Rogalla, D. ³Becker, H. -W. ³Schuetz, H. M. ²Hirst, J. ⁴Mueller, S. ⁴Friedrich, D. ⁴Mitoraj, D. ²Nagli, M. ⁵Toroker, M. Caspary ⁵Eichberger, R. ⁴Beranek, R. ²Devi, A.¹

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作者信息

1. Ruhr Univ Bochum, Inorgan Mat Chem, Univ Str 150, D-44780 Bochum, Germany
2. Ulm Univ, Inst Electrochem, Albert Einstein Allee 47, D-89069 Ulm, Germany
3. Ruhr Univ Bochum, RUBION, Univ Str 150, D-44780 Bochum, Germany
4. Helmholtz Zentrum Berlin Mat & Energie GmbH, Inst Solar Fuels, Hahn Meitner Pl 1, D-14109 Berlin, Germany
5. Technion Israel Inst Technol, Dept Mat Sci & Engn, IL-3200003 Haifa, Israel
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Abstract

In this paper, a direct chemical vapor deposition (CVD) approach is applied for the first time to synthesize high quality copper oxide (CuO), copper tungstate (CuWO4) and tungsten oxide (WO3) on F:SnO2 (FTO) substrates for photocataLytic water splitting. Variation of process parameters enables us to tune the stoichiometry of the deposits to obtain stoichiometric, W-rich, and Cu-rich deposits. It is found that the presence of Cu in WO3 thin films reduces the bandgap and enhances the absorption properties of the material in the visible range. The photoelectrocatalytic performance of stoichiometric CuWO4 was found to be superior to that of WO3 oxide under frontside illumination when thin films were used. However, detailed photoelectrochemical investigations of both thin and thicker CuWO4 fiLms reveal that the incorporation of copper also decreases the mobiLity of both electrons and holes, the Latter being the performance-Limiting factor. These results are in Line with our first-principles calculations of the eLectronic structure of CuWO4. A charge carrier mobiLity and diffusion Length of similar to 6x 10(-3) cm(2) v(-1) s(-1) and 30 nm were determined by time-resolved microwave conductivity measurements, values comparable to those of undoped bismuth vanadate (BiVO4). Our findings establish new insights into the advantages and Limits of CuWO4 -based photoanodes, and suggest a possibility of using very thin CuWO4 fiLms on top of highly absorbing semiconductors with optimal eLectronic properties.

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出版年

2018

Journal of Materials Chemistry

ISSN：2050-7488

被引量15

参考文献量71

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