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

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    18 Citations (Scopus)

    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.

    Original languageEnglish
    Article number13457
    Pages (from-to)18-24
    Number of pages7
    JournalSolid State Ionics
    Volume273
    DOIs
    Publication statusPublished - May 1 2015

    All Science Journal Classification (ASJC) codes

    • Chemistry(all)
    • Materials Science(all)
    • Condensed Matter Physics

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