Preparation and luminescence properties of glass-ceramics containing Sm~(3+)-doped hexagonal NaGdF_4 crystals

摘要

Rare earth-doped hexagonal NaGdF_4 nanocrystals were precipitated from a glass. The glass with the mol% composition 70.1SiO_2·4. 3Al_2O_3·1.8AlF_3·2.3Na _2O·18.5NaF·3.0Gd_2O_3 doped with 8 × 10~(19) Sm~(3+) ions per cm3 was already phase separated after casting. The formed droplets enriched in rare earths and fluoride had sizes in the range mainly from 50 to 90 nm. During annealing at temperatures ≥600 C, multi core particles of hexagonal NaGdF_4 were formed inside the amorphous droplet phase. The fluorescence spectra show that Sm~(3+) is incorporated into the NaGdF_4 lattice. This is confirmed by electron dispersive X-ray analyzes performed in a transmission electron microscope.