Effects of annealing temperature on YAG:Ce synthesized by spray-drying method

In this report, YAG:Ce phosphors were synthesized by spray-drying method. The effects of annealing temperature on crystal structure, morphology and photoluminescence property (PL) of as-prepared samples were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and spectrofluorometer, respectively. The XRD patterns showed all the samples are in consistence with a single garnet phase, and the location of strongest peak shifts to smaller angle with increasing the annealing temperature. The SEM micrographs revealed the sample annealed at 1200 degrees C appears to be a spherical polycrystalline aggregate; as the samples were annealed at 1300-1400 degrees C, spherical grains obviously grow up; but the sample annealed at over 1400 degrees C forms an irregular bulk. The emission spectra of samples indicated the PL of samples annealed at 1200-1400 degrees C improve with increasing the annealing temperature because of the diffusion of SO ions; whereas the PL of sample annealed at the temperature over 1400 degrees C decreases likely resulting from inflection effects of multiangular shape of grains. Therefore, the samples annealed at 1400 degrees C are suitable for gaining phosphor with high brightness and good morphology. (C) 2012 Elsevier GmbH. All rights reserved.