Determining the Atomic Arrangement near the Oxygen Vacancy in Yttrium-Doped Barium Zirconate by Photoluminescence Spectroscopy

Yttrium-doped barium zirconate is a solid electrolyte with several properties that are advantageous for fuel cells. We measure photoluminescence and photoluminescence excitation spectra of anhydrous yttrium-doped barium zirconate to characterize the atomic arrangement near the oxygen vacancy because the local structure is known to strongly influence the protonic conduction. The photoluminescence spectra of our anhydrous sintered pellets are composed of three components: recombination at the grain boundary region, recombination at a vacancy defect with an unpaired electron, and the transition of the electronic state of the oxygen vacancy. From the peak position of the latter photoluminescence component and the corresponding photoluminescence excitation spectrum, we can obtain information on the atomic arrangement that Zr is adjacent to the oxygen vacancies. This information is important for the design of materials with high protonic conductivity.