Luminescence concentration quenching and site-occupancy of Eu2+ ions in Na2Ca2Si3O9 phosphors derived from 45S5 glass-ceramics

• The phosphors of Na2Ca2Si3O9:Eu3+ were first synthesized by sol-gel method.
• Two kinds of Eu2+ sites occupy two kinds of Ca2+ sites in Na2Ca2Si3O9 lattices.
• The structural refinement was confirmed by the general structure analysis system.

The phosphors of Na2Ca2-2xEu2xSi3O9 (x = 0, 0.03, 0.05, 0.07, 0.09) were first synthesized by sol-gel method. The crystal phase formations of the phosphors were detected by X-ray powder diffraction (XRD) measurements and the structure refinement. The photoluminescence spectra, the concentration quenching, the luminescence decay curves and the luminescence color chromaticity were measured, respectively. The excitation spectra indicate that the phosphors can be effectively excited by near UV-LED chips. Two kinds of Eu2+ sites centered at 545 nm and 505 nm were discussed by analyzing the spectra, concentration-dependent luminescence intensity and lifetimes. This is a potential tool for monitoring the bioactivity of 45S5 glass-ceramics in situ.