Crystallization and spectroscopic properties of Eu-doped CaF2 nanocrystals in transparent oxyfluoride glass-ceramics

Transparent oxyfluoride glass-ceramic in the system SiO2–Al2O3–CaF2–EuF2 containing Eu-doped CaF2 nanocrystals were produced by using the controlled crystallization of melt-quenched glass. X-ray diffraction and transmission electron microscopy data have revealed the formation of the CaF2 nanocrystals of about 65 nm size. Photoluminescence spectra have shown an increase of the splitting of the luminescences associated to the Eu3+ ion along with annealing time which is consistent with the Eu3+ environment evolving from a glassy to a crystalline state.