The characterization of Ce/Pr-doped YAG phosphor ceramic for the white LEDs

Ce/Pr -doped YAG (Ce:Pr:YAG) transparent ceramics are fabricated by the vacuum sintering. The crystal structure and morphology, the energy transfer between Ce3+ and Pr3+, and luminescence properties are measured and discussed. The effect of the micrographs of the starting powders and the doping contents of Ce3+ and Pr3+ ions on the microstructure of YAG ceramic is also exhibited. In the photoluminescence spectra, the characteristic emission peaks of Pr3+ ions at 608 nm and 638 nm are observed, and therefore white light-emitting diodes (WLEDs) with improved color-rendering properties obtained by using modified Ce:Pr:YAG phosphors. The composite phase structure of ceramic phosphor is designed for improving the extraction efficacy and increasing the luminous efficacy by breaking the total internal reflection (TIR) at the interface between air and ceramic.