Electrical and Photoelectrochemical Characterization of Single Crystal Bismuth Vanadate
EMSL Project ID
47655
Abstract
Bismuth vanadate (BiVO4) is a promising electrode material in photoelectrochemical (PEC) cells. Recently, it has been shown that doping with Mo and W dramatically improves its performance, but the reasons behind these improvements are unclear. It is likely that these impurities are affecting the electronic properties of this material, but these have not been characterized. In fact, electrical characterization of BiVO4 has only been performed above 673K, where conduction is predominately ionic. The operating temperature range for PEC cells is 300-400K.We have synthesized small (1-5 mm3) single crystal samples of undoped and doped BiVO4 using the floating zone technique. As BiVO4 is semiconducting, the samples are highly resistive and can only be measured on customized apparatus, such as the modified Physical Property Measurement System at PNNL. To the best of our knowledge, no other facility capable of this exists in the country. Further, accurate sample composition is essential, and will be characterized using the Rutherford backscattering spectroscopy (RBS) and proton-induced x-ray emission (PIXE) capabilities at PNNL.
This study will, for the first time, report electronic transport mechanisms and the Hall effect in BiVO4. The effects of Mo and W on carrier concentrations and mobilities will also be elucidated. A better understanding of these underlying mechanisms, only measurable using the unique capabilities at PNNL, will allow us to design better BiVO4-based photoanodes for renewable hydrogen production.
Project Details
Project type
Exploratory Research
Start Date
2012-10-18
End Date
2013-10-18
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Rettie AJ, HC Lee, LG Marshall, JF Lin, C Capen, J Lindemuth, JS McCloy, J Zhou, AJ Bard, and CB Mullins. 2013. "Combined Charge Carrier Transport and Photoelectrochemical Characterization of BiVO4 Single Crystals: Intrinsic Behavior of a Complex Metal Oxide." Journal of the American Chemical Society 135:11389-11396.