title: Vacancy-Induced Electronic Structure Variation of Acceptors and Correlation with Proton Conduction in Perovskite Oxides.
abstract: In most proton-conducing perovskite oxides, the electrostatic attraction between negatively charged acceptor dopants and protonic defects having a positive charge is known to be a major cause of retardation of proton conduction, a phenomenon that is generally referred to as proton trapping. We experimentally show that proton trapping can be suppressed by clustering of positively charged oxygen vacancies to acceptors in BaZrO3-δand BaCeO3-δ. In particular, to ensure the vacancy-acceptor association is effective against proton trapping, the valence electron density of acceptors should not significantly vary when the oxygen vacancies cluster, based on the weak hybridization between the valence d or p orbitals of acceptors and the 2p orbitals of oxygen.
authors.affiliation: Graduate School of EEWS, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Korea.
authors.forename: Hye-Sung
authors.initials: HS
authors.lastname: Kim
authors.affiliation: Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Korea.
authors.forename: Ahreum
authors.initials: A
authors.lastname: Jang
authors.affiliation: Korea Institute of Materials Science, Changwon, 51508, Korea.
authors.forename: Si-Young
authors.initials: SY
authors.lastname: Choi
authors.affiliation: Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Korea.
authors.forename: WooChul
authors.initials: W
authors.lastname: Jung
authors.affiliation: Graduate School of EEWS, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Korea. sychung@kaist.ac.kr, nalphates@gmail.com.
authors.forename: Sung-Yoon
authors.initials: SY
authors.lastname: Chung
keywords: defects; electronic structure; perovskite phases; proton conduction; vacancies