Fabrication and electrochemical characterization of planar Pt–CGO microstructures
Dense, nanocrystalline gadolinia doped ceria (CGO) thin films were prepared by sputtering on a variety of substrates. The CGO films were electrochemically characterized with the aid of interdigitated Pt electrodes by impedance spectroscopy as a function of operating temperature (175–340 °C), CGO fil...
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Veröffentlicht in: | Acta materialia 2008, Vol.56 (2), p.177-187 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | Dense, nanocrystalline gadolinia doped ceria (CGO) thin films were prepared by sputtering on a variety of substrates. The CGO films were electrochemically characterized with the aid of interdigitated Pt electrodes by impedance spectroscopy as a function of operating temperature (175–340
°C), CGO film thickness (157, 233, 315
nm), deposition temperature (room temperature, 300, 500
°C), and Pt electrode pattern geometry (line pattern spacing 10, 15, 25, 50, 100
μm). The different parameter variations enabled the identification of five contributions to the impedance spectra attributed, respectively, to wiring and contacts, grain, grain boundary, current constriction at the triple phase boundary, and electrode effects. The ionic conductivity of the CGO films were characterized by the expression
σ
=
(
A/
T)exp(−
E
A/
kT), with
A
=
10
8.66±0.72
S
cm
−1
K and
E
A
=
0.97
±
0.07
eV with magnitude higher than values reported for both bulk and thin film CGO previously reported in the literature. The electrochemical impedance of the Pt electrodes was found to decrease markedly for CGO films grown at reduced temperatures. Explanations for these observations are presented. |
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ISSN: | 1359-6454 1873-2453 |
DOI: | 10.1016/j.actamat.2007.09.006 |