Epitaxial strain-tuned oxygen vacancy formation, reduction behavior, and electronic structure of perovskite SrIr O3

Matthew E. Sweers, Qing Ma, Patrick M. Donahue, Dennis Nordlund, Sossina M. Haile, Linsey C. Seitz

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

The formation and study of oxygen vacancies are critical for the development of enhanced functional oxides; in the oxygen evolution reaction (OER), oxygen vacancies are proposed to influence the activity and degradation of electrocatalysts. We use thin films of state-of-the-art OER catalyst SrIrO3 deposited on crystal substrates with varied lattice parameters to demonstrate the effect of epitaxial strain on oxygen vacancy formation. Through in situ x-ray diffraction under elevated temperatures and reducing conditions of 3% H2/balance N2, we show that tensile epitaxial strain makes oxygen vacancy formation more favorable, whereas compressive epitaxial strain has no significant effect compared with an unstrained film. We further use in situ and ex situ x-ray absorption spectroscopy to reveal the effect of strain on the favorability of full reduction of Ir species within SrIrO3 films from Ir4+ to Ir0 and on the energy levels of unoccupied electronic states in the out-of-plane direction, respectively. This study adds experimental evidence for the link between strain and oxygen vacancy formation in 5d thin film perovskites, for which the discussion has been dominated by theory-based approaches.

Original languageEnglish (US)
Article number055801
JournalPhysical Review Materials
Volume8
Issue number5
DOIs
StatePublished - May 2024
Externally publishedYes

ASJC Scopus subject areas

  • General Materials Science
  • Physics and Astronomy (miscellaneous)

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