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Experimental analyses for electronic structure of barium zirconate‐strontium zirconate proton‐conducting solid solution
Author(s) -
Matsuo Hiroki,
Murakami Tatsuya,
Otomo Junichiro
Publication year - 2021
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.17935
Subject(s) - band gap , analytical chemistry (journal) , materials science , zirconate , valence (chemistry) , ionization energy , electronic structure , proton , semimetal , electronic band structure , ionization , solid solution , chemistry , condensed matter physics , optoelectronics , ion , ceramic , computational chemistry , physics , organic chemistry , chromatography , quantum mechanics , metallurgy , composite material , titanate
In proton‐conducting oxides, analyses for their electronic structure contribute to the understanding of interactions between defects in them. In this study, electronic band alignment of (1− x )BaZr 0.8 Y 0.2 O 3−δ (BZY)– x SrZr 0.95 Y 0.05 O 3−δ (SZY) proton‐conducting solid‐solution system (BSZY) which has high defect concentration and the deep valence band is experimentally investigated. By using thin‐film specimens for optical absorption measurements, absorption edges derived from electron transition from the valence band to the conduction band which was insensitive to the proton incorporation were clearly observed in spite of the high defect concentration. The obtained optical band gap energy increased from 5.61 to 5.89 eV with increasing x , which was consistent with a composition dependence of Zr(Y)O 6 octahedral tilting. Ultraviolet photon‐yield spectroscopy (UV‐PYS) measurements under vacuum condition revealed that BZY and SZY had ionization energy of 6.98 and 7.31 eV, respectively, and thus the absolute energy levels of the valence band maximum and the conduction band minimum of BSZY were experimentally clarified. We propose that the combination of the optical absorption measurements using thin‐film specimens and the UV‐PYS measurements under vacuum condition is effective in evaluating fundamental electronic structures of proton‐conducting oxides.