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Oxygen vacancies and pseudo Jahn‐Teller destabilization in cesium‐doped hexagonal tungsten bronzes
Author(s) -
Okada Mika,
Ono Katsushi,
Yoshio Satoshi,
Fukuyama Hideaki,
Adachi Kenji
Publication year - 2019
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.16414
Subject(s) - tungsten , raman spectroscopy , x ray photoelectron spectroscopy , alkali metal , oxygen , jahn–teller effect , materials science , octahedron , doping , crystallography , inorganic chemistry , ion , crystal structure , chemistry , analytical chemistry (journal) , nuclear magnetic resonance , physics , optoelectronics , organic chemistry , optics , metallurgy , chromatography
Abstract Structural and compositional changes of Cs‐doped hexagonal tungsten bronzes ( HTB ) with respect to variations in oxygen deficiency and alkali content have been investigated in detail through x‐ray diffraction Rietveld analysis, x‐ray photoelectron spectroscopy, and Raman spectroscopy. Cs‐ HTB crystallized in a reductive atmosphere is evidenced to generally contain plenty of oxygen defects, and a general formula, Cs x WO 3− y (0.20 ≤ x ≤ 0.32, 0 < y ≤ 0.46), is proposed. Lattice parameters of Cs‐ HTB are observed to vary according to the relation, c (Å) = −3.436 a (Å) + 33.062. The coordinated modification of W–O octahedral dimensions suggests the origin of the structural change with increasing x and y to be a destabilization of the pseudo Jahn‐Teller distortion due to donated electrons. The dimensional change of lattice due to electrons emitted from oxygen defects is appraised only 1/18 as that due to electrons from doped alkali ions, suggesting that most electrons from oxygen defects should be localized in Cs‐ HTB .