TY - JOUR
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.
N1 - Funding Information:
NHP gratefully acknowledges support from JSPS KAKENHI grant number 25820334 . NHP and SRB recognize partial support from I2CNER , supported by the World Premier International Research Center Initiative (WPI) , MEXT, Japan . HLT thanks the Basic Energy Sciences, U.S. Department of Energy under award DE-SC0002633 for research support. The authors would like to thank Mr. Takeshi Daio for TEM-EDS measurements of thin film composition.
Publisher Copyright:
© 2014 Elsevier B.V. All rights reserved.
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.
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U2 - 10.1016/j.ssi.2014.09.013
DO - 10.1016/j.ssi.2014.09.013
M3 - Article
AN - SCOPUS:84939954494
SN - 0167-2738
VL - 273
SP - 18
EP - 24
JO - Solid State Ionics
JF - Solid State Ionics
M1 - 13457
ER -