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Schlagwörter:
Bromine compounds; Chlorine compounds; Europium compounds; Glass ceramics; Glass transition; Indium; Indium compounds; Photoluminescence spectroscopy; X ray absorption, Doped ceramics; Fluorozirconate; Hexagonal phase; Indium doping; Indium-free; Orthorhombic structures; Oxidation state; PL spectroscopy, Barium compounds
Zusammenfassung:
The influence of adding InF3 as a reducing agent on the oxidation state of Eu in fluoro-chloro- (FCZ) and fluorobromozirconate (FBZ) glass ceramics was investigated using x-ray absorption near edge (XANES) and photoluminescence (PL) spectroscopy. For both materials, it was found that InF3 decreases the Eu2+-to-Eu3+ ratio significantly. PL spectroscopy proved that an annealing step leads to the formation of Eu-doped BaCl2 and BaBr2 nanocrystals in the FCZ and FBZ glasses, respectively. In the case of FCZ glass ceramics the hexagonal phase of BaCl2 could be detected in indium-free and InF3-doped ceramics, but only for InF3 containing FCZ glass ceramics a phase transition of the nanoparticles from hexagonal to orthorhombic structure is observed. For the FBZ glass ceramics, the hexagonal phase of BaBr2 can be formed with and without indium doping, but only in the indium-free case a phase transition to orthorhombic BaBr2 could be found. © 2010 Materials Research Society.
