Tracer diffusion and chemical diffusion of oxygen in acceptor doped SrTiO 3

Claus, J.; Leonhardt, M.; Maier, Joachim

doi:10.1016/s0022-3697(99)00421-7

Cited by 69 publications

(119 citation statements)

References 39 publications

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“…; thus, they represent to some degree hypothetical quantities, e.g., pure water uptake for a material which according to its high [ 20,25 ] SrTiO 3 , [ 50,51 ] or SOFC cathode materials. [52][53][54] As realistic example, we chose D VO for p O2 changes in Figure 5 .…”

Section: Discussionmentioning

confidence: 99%

Stoichiometry Variation in Materials with Three Mobile Carriers—Thermodynamics and Transport Kinetics Exemplified for Protons, Oxygen Vacancies, and Holes

Poetzsch

Merkle

Maier

2015

Adv Funct Materials

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Materials with three independent mobile charge carriers, in the sense of not being in local defect‐chemical equilibrium though naturally coupled through electroneutrality, are encountered in various cases of scientific and technological relevance. Examples are proton conducting perovskites under conditions at which hole and also oxygen vacancy conductivity may become significant, and mixed conducting cathode materials suited for fuel cells using proton conducting oxide electrolytes. Already the thermodynamics of the equilibrium situation is complex as a increase can lead to proton incorporation by water uptake (pure acid–base reaction) or by hydrogenation (redox reaction). As far as the even more complex transport kinetics are concerned, diffusion equations are derived which are exact for the interaction‐free (ideally dilute) situation. Kinetic implications are discussed and checked by exemplary numerical simulations. The treatment includes simple sub‐cases such as onefold relaxation on change, as well as complex patterns characterized by the appearance of more than one characteristic time scales (“twofold relaxation”) or apparent “moving boundary” kinetics. Implications for stability and functionality of ceramic materials are discussed.

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Section: Discussionmentioning

confidence: 99%

Stoichiometry Variation in Materials with Three Mobile Carriers—Thermodynamics and Transport Kinetics Exemplified for Protons, Oxygen Vacancies, and Holes

Poetzsch

Merkle

Maier

2015

Adv Funct Materials

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“…12 Iron is commonly used because it is cheap, readily available, and makes the Fe-doped ceramic STO (Fe:STO) insulating through compensation.…”

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confidence: 99%

“…3,12,[18][19][20][21] These models then adjust the ionization of the Fe dopant until predictions fit a measured physical property. Nevertheless, a number of EPR studies have detected the presence of a first nearest neighbor iron oxygen vacancy complex, which suggests this interaction is non-negligible.…”

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confidence: 99%

Defect mechanisms of coloration in Fe-doped SrTiO3 from first principles

Baker

Bowes

Long

et al. 2017

Applied Physics Letters

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To understand the underlying defect mechanisms governing the coloration of Fe-doped SrTiO3 (Fe:STO), density functional theory calculations were used to determine defect formation energies and to interpret optical absorption spectra. A grand canonical defect equilibrium model was developed using the calculated formation energies, which enabled connection to annealing experiments. It was found that FeTi0 is stable in oxidizing conditions and leads to the optical absorption signatures in oxidized Fe:STO, consistent with experiment. Fe:STO was found to transition from brown to transparent as PO2 was reduced during annealing. The defect equilibrium model reproduces a consistent PO2 of this coloration transition. Most critical to reproducing the PO2 of the coloration transition was inclusion of a FeTi-VO first nearest neighbor complex, which was found to be strongly interacting. The coloration transition PO2 was found to be insensitive to the presence of minority background impurities, slightly sensitive to Fe content, and more sensitive to annealing temperature.

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“…x Fe x O 3-δ ) as the model system for our studies, given its well studied electronic structure, 6 optical properties, 7,8 defect chemistry, 9,10,11,12 electronic and ionic transport properties, 13,14,15,16 surface and grain boundary properties. 17,18,19,20 Our group has extensive experience with SrTiO 3 as a photoelectrode, 21 with its high temperature electrical properties, its defect structure and transport characteristics and its optical properties.…”

Section: B Model Electrode Materialsmentioning

confidence: 99%

Photo-Activated Low Temperature, Micro Fuel Cell Power Source

Tuller¹

2007

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-A Key objective of this program is to identify electrodes that will make it possible to significantly reduce the operating temperature of micro-SOFC and thin film-based SOFCs. Towards this end, efforts are directed towards a) identifying the key rate limiting steps which limit presently utilized electrodes from performing at reduced temperatures, as well as, b) investigating the use of optical, as opposed to thermal energy, as a means for photocatalyzing electrode reactions and enabling reduced operating temperatures. During Phase I, the following objectives were achieved: a) assembly and testing of our unique Microprobe Thin Film Characterization System; b) fabrication of the model cathode materials system in thin film form by both PLD and ink jet printing; and c) the successful configuration and testing of the model materials as cathodes in electrochemical cells. A further key objective d) to test the potential of illumination in enhancing electrode performance was also achieved.

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Tracer diffusion and chemical diffusion of oxygen in acceptor doped SrTiO 3

Cited by 69 publications

References 39 publications

Stoichiometry Variation in Materials with Three Mobile Carriers—Thermodynamics and Transport Kinetics Exemplified for Protons, Oxygen Vacancies, and Holes

Stoichiometry Variation in Materials with Three Mobile Carriers—Thermodynamics and Transport Kinetics Exemplified for Protons, Oxygen Vacancies, and Holes

Defect mechanisms of coloration in Fe-doped SrTiO3 from first principles

Photo-Activated Low Temperature, Micro Fuel Cell Power Source

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