Transference Numbers for In-Plane Carrier Conduction in Thin Film Nanostructured Gadolinia-Doped Ceria Under Varying Oxygen Partial Pressure
We demonstrate a modified Hebb–Wagner approach to quantitatively estimate transference numbers for carrier conduction in thin film oxide conductors using blocking electrodes in an in-plane geometry. We report ionic transference numbers, ti, for gadolinia-doped ceria (GDC) thin films, a model mixed ion–electron conductor, at 973K and oxygen partial pressure ranging from 0.21 atm down to approximately 10−22 atm. Our results indicate that GDC reaches the electrolytic regime (ti=0.5) at an oxygen partial pressure of 5 × 10−19 atm at 973K. This approach may be useful for understanding carrier transport mechanisms in low-dimensional oxide heterostructures with specific relevance to nanostructured energy materials.
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Document Type: Research Article
Affiliations: Harvard School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138
Publication date: October 1, 2009