Efficient solid-state route for the preparation of spherical YAG: Ce phosphor particles

The formation of Y3Al5O12:Ce3+ (YAG:Ce) powders from the corresponding submicrometer-sized oxides and 5 wt% BaF2 flux is studied at different heating temperatures. The reaction powders are characterized using XRD, SEM, and TEM-EDS. X-ray analysis reveals the sequential formation of the Y4Al2O9 (YAM), YAlO3 (YAP), and Y3Al5O12 (YAG) phases in the temperature range of 1000-1300 degrees C. It is shown that the nucleation process occurs via the dissolution-precipitation mechanism, whereas the grain growth process is controlled via the liquid-phase diffusion route. YAG:Ce phosphor particles prepared using a proposed technique exhibit a spherical shape, high crystallinity, and an emission intensity that is approximately 10-15% greater than that of commercial phosphor powder. (C) 2010 Elsevier B.V. All rights reserved.