Relation between material structure and photoluminescence properties in yttrium–aluminum borates phosphors
Résumé
Glassy yttrium and aluminum borate powders (g-YAB) were synthesized by the polymeric precursor method (modified Pechini). We report here a detailed study of the structural, spectroscopic, and optical characterizations of the g-YAB powders, involving several complementary techniques: thermal analysis, X-ray powder diffraction, and electron microscopy combined with IR, nuclear magnetic resonance, and electron paramagnetic resonance spectroscopies. All these results, directly correlated with the photoluminescence (PL) properties of the g-YAB phosphors, allow us to argue that the PL emissions come from large polyaromatic molecules auto-generated from organic precursors and trapped in the glassy network of the g-YAB during thermal treatments. These extended aromatic molecules (seven rings and more corresponding to polycyclic aromatic hydrocarbons) must have been produced during the pyrolysis treatment of the powders, in which a large fraction of the protons was replaced during the calcination process by hydroxyl groups, or other oxygen-containing groups.
Domaines
Chimie| Origine | Fichiers produits par l'(les) auteur(s) |
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