abstract
Gallium fluoride phosphate glasses feature low refractive index, high energy radiation resistance, wide transmission range, and favorable emission characteristics of rare-earth dopants. For the development of optimized glass compositions, a fundamental understanding of these properties in terms of glass structure is sought. We report nuclear magnetic resonance (NMR) structural studies of glasses in the system xGa(PO3)(3)-(40 - x)GaF3-20BaF(2)-20ZnF(2)-20SrF(2) (x = 5, 10, 15, 20, and 25 mol%). P-31 NMR results with Ga-71 recoupling show that the network structure is dominated by P-O-Ga linkages, and no P-O-P linkages exist. Ga-71 NMR results show that Ga is mainly six-coordinated featuring a mixed fluoride/phosphate coordination. Quantitative estimates of this ligand distribution around gallium were obtained by Ga-71{P-31} spin echo double resonance (REDOR) measurements. Photophysical properties suggest changes in the Eu(III) ligand distribution toward a fluoride-dominated environment at low P/F ratio while the glass network is largely sustained by bridging oxygen atoms via P-O-Ga linkages.
keywords
RARE-EARTH IONS; FLUOROPHOSPHATE GLASSES; LOCAL-STRUCTURE; FLUOROALUMINATE GLASS; LASING PROPERTIES; LUMINESCENCE; FIBER; PHOTOLUMINESCENCE; SYSTEMS; EU3+
subject category
Materials Science
authors
Gaddam, A; Galleani, G; Reis, VD; de Camargo, ASS; Eckert, H
our authors
Anuraag Gaddam
Assistant Researcheracknowledgements
Fundacao de Amparo a Pesquisa do Estado de Sao Paulo, Grant/Award Numbers: 2013/07793-6, 2021/06370-0