Defect chemistry and surface oxygen exchange kinetics of La-doped Sr(Ti,Fe)O3 - α in oxygen-rich atmospheres

Nicola H. Perry; Daniele Pergolesi; Sean R. Bishop; Harry L. Tuller

doi:10.1016/j.ssi.2014.09.013

Defect chemistry and surface oxygen exchange kinetics of La-doped Sr(Ti,Fe)O_{3 - α} in oxygen-rich atmospheres

Nicola H. Perry, Daniele Pergolesi, Sean R. Bishop, Harry L. Tuller

Research output: Contribution to journal › Article › peer-review

Abstract

Abstract The mixed ionic and electronic conductor Sr(Ti,Fe)O_3-α (STF) exhibits fast oxygen surface exchange kinetics, with electron concentration potentially playing a key role. The effect of La donor doping on electron concentration, Fermi level, and overall defect chemistry of STF is investigated on Sr_1-yLa_yTi_0.65Fe_0.35O_3-α (LSTF, 0 ≤ y ≤ 0.5) thin films. Defect chemical modeling, optical absorption, and electrical conductivity measurements in oxidizing conditions indicate compensation of donors by an increase in oxygen and electron concentrations, increase in Fermi level, decrease in oxygen vacancy and hole concentrations, and formation of cation vacancies (for [La] > [Fe]). The surface exchange coefficient, measured by impedance spectroscopy, decreased with increasing donor concentration, suggesting that oxygen exchange kinetics in LSTF are limited by low oxygen vacancy and/or hole concentrations, rather than electron transfer.

Original language	English (US)
Article number	13457
Pages (from-to)	18-24
Number of pages	7
Journal	Solid State Ionics
Volume	273
DOIs	https://doi.org/10.1016/j.ssi.2014.09.013
State	Published - May 1 2015
Externally published	Yes

Keywords

Defect chemistry
Electrical conductivity
Optical absorption
Oxygen surface exchange
SrTiO
Thin films

ASJC Scopus subject areas

General Chemistry
General Materials Science
Condensed Matter Physics

Online availability

10.1016/j.ssi.2014.09.013

Library availability

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Cite this

@article{eec8a671913143b4a4dac3df9b9c5d5b,

title = "Defect chemistry and surface oxygen exchange kinetics of La-doped Sr(Ti,Fe)O3 - α in oxygen-rich atmospheres",

abstract = "Abstract The mixed ionic and electronic conductor Sr(Ti,Fe)O3-α (STF) exhibits fast oxygen surface exchange kinetics, with electron concentration potentially playing a key role. The effect of La donor doping on electron concentration, Fermi level, and overall defect chemistry of STF is investigated on Sr1-yLayTi0.65Fe0.35O3-α (LSTF, 0 ≤ y ≤ 0.5) thin films. Defect chemical modeling, optical absorption, and electrical conductivity measurements in oxidizing conditions indicate compensation of donors by an increase in oxygen and electron concentrations, increase in Fermi level, decrease in oxygen vacancy and hole concentrations, and formation of cation vacancies (for [La] > [Fe]). The surface exchange coefficient, measured by impedance spectroscopy, decreased with increasing donor concentration, suggesting that oxygen exchange kinetics in LSTF are limited by low oxygen vacancy and/or hole concentrations, rather than electron transfer.",

keywords = "Defect chemistry, Electrical conductivity, Optical absorption, Oxygen surface exchange, SrTiO, Thin films",

author = "Perry, {Nicola H.} and Daniele Pergolesi and Bishop, {Sean R.} and Tuller, {Harry L.}",

year = "2015",

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doi = "10.1016/j.ssi.2014.09.013",

language = "English (US)",

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journal = "Solid State Ionics",

issn = "0167-2738",

publisher = "Elsevier B.V.",

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T1 - Defect chemistry and surface oxygen exchange kinetics of La-doped Sr(Ti,Fe)O3 - α in oxygen-rich atmospheres

AU - Perry, Nicola H.

AU - Pergolesi, Daniele

AU - Bishop, Sean R.

AU - Tuller, Harry L.

PY - 2015/5/1

Y1 - 2015/5/1

N2 - Abstract The mixed ionic and electronic conductor Sr(Ti,Fe)O3-α (STF) exhibits fast oxygen surface exchange kinetics, with electron concentration potentially playing a key role. The effect of La donor doping on electron concentration, Fermi level, and overall defect chemistry of STF is investigated on Sr1-yLayTi0.65Fe0.35O3-α (LSTF, 0 ≤ y ≤ 0.5) thin films. Defect chemical modeling, optical absorption, and electrical conductivity measurements in oxidizing conditions indicate compensation of donors by an increase in oxygen and electron concentrations, increase in Fermi level, decrease in oxygen vacancy and hole concentrations, and formation of cation vacancies (for [La] > [Fe]). The surface exchange coefficient, measured by impedance spectroscopy, decreased with increasing donor concentration, suggesting that oxygen exchange kinetics in LSTF are limited by low oxygen vacancy and/or hole concentrations, rather than electron transfer.

AB - Abstract The mixed ionic and electronic conductor Sr(Ti,Fe)O3-α (STF) exhibits fast oxygen surface exchange kinetics, with electron concentration potentially playing a key role. The effect of La donor doping on electron concentration, Fermi level, and overall defect chemistry of STF is investigated on Sr1-yLayTi0.65Fe0.35O3-α (LSTF, 0 ≤ y ≤ 0.5) thin films. Defect chemical modeling, optical absorption, and electrical conductivity measurements in oxidizing conditions indicate compensation of donors by an increase in oxygen and electron concentrations, increase in Fermi level, decrease in oxygen vacancy and hole concentrations, and formation of cation vacancies (for [La] > [Fe]). The surface exchange coefficient, measured by impedance spectroscopy, decreased with increasing donor concentration, suggesting that oxygen exchange kinetics in LSTF are limited by low oxygen vacancy and/or hole concentrations, rather than electron transfer.

KW - Defect chemistry

KW - Electrical conductivity

KW - Optical absorption

KW - Oxygen surface exchange

KW - SrTiO

KW - Thin films

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