Synthesis and luminescent properties of Eu3+/Eu2+ co-doped calcium aluminosilicate glass-ceramics

Eu3+ and Eu2+ co-doped calcium aluminosilicate glass-ceramics have been prepared by devitrification of calcium aluminosilicate glass using heat-treatment. Control of crystallization in the glass-ceramics was studied by X-ray diffraction (XRD) and Raman spectroscopy. The results showed that crystalline phases in glass-ceramic belong to the family of melilite Ca2Mg0.25Al1.5Si1.25O7 as the major phase and anorthite CaAl2Si2O8 as the minor phase. Luminescent properties were investigated by emission; lifetime and the color points were calculated. Emission spectra showed that Eu2+ entered into the crystalline phase in a two steps mechanism: first as Eu3+ which is then reduced to Eu2+. This incorporation in the crystal enhanced Eu2+ emission with increasing time of heat-treatment and therefore crystallization.