Y2SiO5 : Ce phosphor particles 0.5-1.4 mu m in size with spherical morphology

Abstract

Ce-doped Y2SiO5 phosphor particles with spherical morphology, small size, high crystallinity, and good photoluminescence (PL) intensity were prepared by spray pyrolysis. The characteristics of prepared particles were compared with those of commercial ones. The particles annealed above 1000 degrees C had a clear crystallinity of Y2SiO5, and the crystal structure changed from X-1 to X-2 type after annealing above 1200 degrees C. The mean size of the particles increased from 0.5 to 1.4 mu m when the overall solution concentrations were varied from 0.045 to 0.9 mol/liter. The photoluminescence intensity and crystallinity of particles increased as the particle size and preparation temperature were increased. The annealed particles larger than 0.8 mu m maintained a spherical morphology. Emission of blue light was observed after annealing above 1000 degrees C on excitation with an UV light. The PL spectra particles annealed below 1100 degrees C had maximum values at 450 nm, and shifted to the smaller wavelengths after annealing above 1200 degrees C. The brightness of particles increased with increasing annealing temperatures due to favorable crystallization and had a maximum at 1400 degrees C. The particles annealed above 1400 degrees C exhibited intensities higher than those of particles produced commercially. (C) 1999 Academic Press.