Optical spectroscopy investigation on distribution of Eu3+ in nanostructured glass ceramics

The time-resolved luminescence spectra of the Eu3+ doped SiO2-Al2O3-NaF-YF3-EuF3 precursor glass reveal that Eu3+ ions locate in both the oxygen-coordination environment and the fluorine-coordination one. After crystallization induced by heat treatment, the orthorhombic YF3 nanocrystals with mean size of 22 nm embedded homogeneously in the glassy matrix. The Stark splitting emission, the low electric dipole 5D0→7F2 transition, the disappearance of the O2--Eu3+ charge transfer band and the reduction in Ω2 value indicate the partition of Eu3+ into the YF3 lattice. Moreover, the nearly single-exponential luminescence decay curves of the Eu3+:5D0 and 5D1 levels for the 0.1%Eu3+ doped glass ceramic evidence that Eu3+ ions mainly occupy the Y3+ sites.