Oxygen surface exchange kinetics measurement by simultaneous optical transmission relaxation and impedance spectroscopy: Sr(Ti,Fe)O3-x thin film case study
We compare approaches to measure oxygen surface exchange kinetics, by simultaneous optical transmission relaxation (OTR) and AC-impedance spectroscopy (AC-IS), on the same mixed conducting SrTi0.65Fe0.35O3-x film. Surface exchange coefficients were evaluated as a function of oxygen activity in the f...
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| Format: | Article |
| Language: | English |
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Taylor & Francis Group
2018-12-01
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| Series: | Science and Technology of Advanced Materials |
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| Online Access: | http://dx.doi.org/10.1080/14686996.2018.1430448 |
| _version_ | 1818695361405911040 |
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| author | Nicola H. Perry Jae Jin Kim Harry L. Tuller |
| author_facet | Nicola H. Perry Jae Jin Kim Harry L. Tuller |
| author_sort | Nicola H. Perry |
| collection | DOAJ |
| description | We compare approaches to measure oxygen surface exchange kinetics, by simultaneous optical transmission relaxation (OTR) and AC-impedance spectroscopy (AC-IS), on the same mixed conducting SrTi0.65Fe0.35O3-x film. Surface exchange coefficients were evaluated as a function of oxygen activity in the film, controlled by gas partial pressure and/or DC bias applied across the ionically conducting yttria-stabilized zirconia substrate. Changes in measured light transmission through the film over time (relaxations) resulted from optical absorption changes in the film corresponding to changes in its oxygen and oxidized Fe (~Fe4+) concentrations; such relaxation profiles were successfully described by the equation for surface exchange-limited kinetics appropriate for the film geometry. The kchem values obtained by OTR were significantly lower than the AC-IS derived kchem values and kq values multiplied by the thermodynamic factor (bulk or thin film), suggesting a possible enhancement in k by the metal current collectors (Pt, Au). Long-term degradation in kchem and kq values obtained by AC-IS was also attributed to deterioration of the porous Pt current collector, while no significant degradation was observed in the optically derived kchem values. The results suggest that, while the current collector might influence measurements by AC-IS, the OTR method offers a continuous, in situ, and contact-free method to measure oxygen exchange kinetics at the native surfaces of thin films. |
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| format | Article |
| id | doaj.art-e4553e497cf04a8db0d4f0256533bbca |
| institution | Directory Open Access Journal |
| issn | 1468-6996 1878-5514 |
| language | English |
| last_indexed | 2024-12-17T13:44:15Z |
| publishDate | 2018-12-01 |
| publisher | Taylor & Francis Group |
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| series | Science and Technology of Advanced Materials |
| spelling | doaj.art-e4553e497cf04a8db0d4f0256533bbca2022-12-21T21:46:12ZengTaylor & Francis GroupScience and Technology of Advanced Materials1468-69961878-55142018-12-0119113014110.1080/14686996.2018.14304481430448Oxygen surface exchange kinetics measurement by simultaneous optical transmission relaxation and impedance spectroscopy: Sr(Ti,Fe)O3-x thin film case studyNicola H. Perry0Jae Jin Kim1Harry L. Tuller2Kyushu UniversityMassachusetts Institute of TechnologyKyushu UniversityWe compare approaches to measure oxygen surface exchange kinetics, by simultaneous optical transmission relaxation (OTR) and AC-impedance spectroscopy (AC-IS), on the same mixed conducting SrTi0.65Fe0.35O3-x film. Surface exchange coefficients were evaluated as a function of oxygen activity in the film, controlled by gas partial pressure and/or DC bias applied across the ionically conducting yttria-stabilized zirconia substrate. Changes in measured light transmission through the film over time (relaxations) resulted from optical absorption changes in the film corresponding to changes in its oxygen and oxidized Fe (~Fe4+) concentrations; such relaxation profiles were successfully described by the equation for surface exchange-limited kinetics appropriate for the film geometry. The kchem values obtained by OTR were significantly lower than the AC-IS derived kchem values and kq values multiplied by the thermodynamic factor (bulk or thin film), suggesting a possible enhancement in k by the metal current collectors (Pt, Au). Long-term degradation in kchem and kq values obtained by AC-IS was also attributed to deterioration of the porous Pt current collector, while no significant degradation was observed in the optically derived kchem values. The results suggest that, while the current collector might influence measurements by AC-IS, the OTR method offers a continuous, in situ, and contact-free method to measure oxygen exchange kinetics at the native surfaces of thin films.http://dx.doi.org/10.1080/14686996.2018.1430448Thin filmsperovskitemixed ionic and electronic conductoroxygen surface exchangeoptical absorptionimpedance spectroscopy |
| spellingShingle | Nicola H. Perry Jae Jin Kim Harry L. Tuller Oxygen surface exchange kinetics measurement by simultaneous optical transmission relaxation and impedance spectroscopy: Sr(Ti,Fe)O3-x thin film case study Science and Technology of Advanced Materials Thin films perovskite mixed ionic and electronic conductor oxygen surface exchange optical absorption impedance spectroscopy |
| title | Oxygen surface exchange kinetics measurement by simultaneous optical transmission relaxation and impedance spectroscopy: Sr(Ti,Fe)O3-x thin film case study |
| title_full | Oxygen surface exchange kinetics measurement by simultaneous optical transmission relaxation and impedance spectroscopy: Sr(Ti,Fe)O3-x thin film case study |
| title_fullStr | Oxygen surface exchange kinetics measurement by simultaneous optical transmission relaxation and impedance spectroscopy: Sr(Ti,Fe)O3-x thin film case study |
| title_full_unstemmed | Oxygen surface exchange kinetics measurement by simultaneous optical transmission relaxation and impedance spectroscopy: Sr(Ti,Fe)O3-x thin film case study |
| title_short | Oxygen surface exchange kinetics measurement by simultaneous optical transmission relaxation and impedance spectroscopy: Sr(Ti,Fe)O3-x thin film case study |
| title_sort | oxygen surface exchange kinetics measurement by simultaneous optical transmission relaxation and impedance spectroscopy sr ti fe o3 x thin film case study |
| topic | Thin films perovskite mixed ionic and electronic conductor oxygen surface exchange optical absorption impedance spectroscopy |
| url | http://dx.doi.org/10.1080/14686996.2018.1430448 |
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