Green-emitting yttrium silicate phosphor particles prepared by large scale ultrasonic spray pyrolysis

Tb doped Y₂SiO₅ phosphor particles with spherical morphology, fine size, high crystallinity and good photoluminescence intensity were prepared by spray pyrolysis. The colloidal solution obtained by adding the fumed silica particles was introduced to control the characteristics of Y₂SiO₅: Tb phosphor particles. The particles prepared from the colloidal solution had a spherical and filled morphology even after post-treatment. The particles post-treated below 1,200 ‡C had X1 type crystal structure but the crystal structure changed from X1 to X2 after post-treatment above 1,300 ‡C. When crystal structure was changed from X1 to X2, the PL intensity greatly increased. The maximum PL intensity of particles, which were prepared from the solution with 120% excess of stoichiometric fumed silica, was about 4 times higher than that of the particles prepared from the stoichiometric solution. The particles prepared from the stoichiometric solution of yttrium nitrate and fumed silica had mixed phases of X1 and X2 type and had impurity as Y₂O₃. On the other hand, the particles prepared from the solution with 120% excess of stoichiometric fumed silica had high crystallinity of X2 type.