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Hoang, K., Latouche, C. & Jobic, S. (2022) Why is it so difficult to realize Dy4+ in as-synthesized BaZrO3? J. Am. Ceram. Soc.
Added by: Richard Baschera (2022-03-25 10:58:41) Last edited by: Richard Baschera (2022-03-25 10:59:47) |
| Type de référence: Article DOI: 10.1111/jace.18427 Numéro d'identification (ISBN etc.): 0002-7820 Clé BibTeX: Hoang2022 Voir tous les détails bibliographiques  |
Catégories: INTERNATIONAL, MIOPS Mots-clés: behavior, Defects, dopants, Doping, effective ionic-radii, expansion, first-principles theory, Luminescence, rare earths, site occupancy, spectra Créateurs: Hoang, Jobic, Latouche Collection: J. Am. Ceram. Soc. |
Consultations : 1/438
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| Liens URLs https://www.webofs ... OS:000765377100001 |
| Résumé |
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Rare-earth doped barium zirconate (BaZrO3) ceramics are of interest as proton-conducting and luminescent materials. Here, we report a study of dysprosium (Dy) and other relevant point defects in BaZrO3 using hybrid density-functional defect calculations. The tetravalent Dy4+ is found to be structurally and electronically stable at the Zr lattice site (i.e., as Dy-Zr(0)), but most often energetically less favorable than the trivalent Dy3+ (i.e., Dy-Zr(-)) in as-synthesized BaZrO3, due to the formation of low-energy, positively charged oxygen vacancies and the mixed-site occupancy of Dy in the host lattice. The Dy4+/Dy3+ ratio can, in principle, be increased by preparing the material under highly oxidizing and Ba-rich conditions and co-doping with acceptor-like impurities; however, a post-synthesis treatment may still be needed to realize a nonnegligible Dy4+ concentration. We also find that certain unoccupied Dy 4f states and the O 2p states in the Dy-Zr(0) configuration are strongly hybridized, a feature not often seen in rare-earth-containing materials, and that the isolated Dy-Zr defect might be the source of a broad blue emission in band-to-defect ("charge-transfer") luminescence.
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Place: Hoboken Publisher: Wiley WOS:000765377100001
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