Crystallization Mechanism and Photoluminescence Properties of CaF2–Al2O3–SiO2: Eu Glass-Ceramics Based on Nano-Scale Phase Separation Phenomenon

Abstract

In this paper, CaF2–Al2O3–SiO2 glass containing nano-sized CaF2 crystals were fabricated using phase separation phenomenon and the effects of rare earth ion (Eu) addition on the optical properties were investigated. The formation conditions for nano-sized CaF2 crystal phase were confirmed using non-isothermal analysis and X-ray diffraction (XRD) measurement, while inhibiting anorthite or wollastonite crystal formation. The phase separation phenomenon in the mother glass and the nano-sized crystals generated by heat treatment were observed through the microstructure analysis using scanning electron microscopy (SEM). In addition, photoluminescence (PL) spectra and decay time analysis were performed to confirm the emission characteristics of Eu-doped glass-ceramics. The Eu-doped glass-ceramics produced in this study showed strong red light. The overall luminescence properties according to the heat treatment temperatures were found to shift from red to blue as indicated in the Commission International de l’Eclairage (CIE) color coordinate system.