Preparation and Luminescence Properties of Ce, Pr Doped YAG Glass Ceramics

Using Y2O3-Al2O3-SiO2-Li2O-K2O-Na2O as Ce-doping or Ce, Pr co-doping glass matrix, Ce:YAG and Ce, Pr:YAG glass ceramic for White-LED (WLED) was prepared by heat treatment of the glass matrix. The formation of YAG crystal phase, morphology, luminescence properties and lifetime were examined by X-ray diffraction (XRD), Field-emission scanning electron microscopy. (FE-SEM) and photoluminescence spectroscopy. XRD analysis indicates that pure YAG phase is formed by heat treating at 1 400 degrees C. Characteristic excitation peak located at 466 nm is observed in the excitation spectra of the Ce:YAG or Ce, Pr:YAG glass ceramic. A broad emission band from 480 similar to 700 nm, centered at 531 nm is produced with blue light excitation. A narrow emission peak is located at 609 nm in Ce, Pr:YAG glass ceramic, which may improve the color rendering index (CRI)of WLED. Different Pr-codoping experiments show that the maximum is achieved with samples doped with the 5:6 (n(Ce):n(Pr)) ratio. Decay curves for the fluorescence of Ce:YAG glass-ceramic test show that the lifetime of the Ce:YAG glass ceramic is longer than that of the Ce, Pr:YAG glass ceramic.