Synthesis of Spherical (Y, Gd)BO3:Eu3+ Phosphor Using W/O Emulsion System

Spherical (Y, Gd)BO3:Eu3+ phosphor particles with a narrow size distribution (2 ∼ 4 μm) was obtained by firing the Y-Gd-Eu-BO3 precursor prepared in a W/O style emulsion system. In the W/O emulsion system, kerosene, used as oil phase, was mixed with Span 80 and Tween 80 compounds which were employed as the emulsifier with an HLB (hydrophile-lipophile balance) value of 5.2 ∼ 5.3. Both rare earths (Y, Gd and Eu) nitrate and boric acid solution or ammonia solution were used as aqueous phase. The synthesis conditions, such as emulsion composition, emulsifying style, precipitation reaction process, reaction temperature, morphology control, and so on, were investigated, and the optimum synthesis conditions for preparing spherical (Y, Gd)BO3:Eu3+ phosphor was obtained. The phosphor was characterized by XRD. SEM, laser particle size analysis, emission and excitation spectrum under vacuum ultraviolet (VUV), and so on. The phosphor synthesized using the water-in-oil emulsion method with median diameter (D50) of 2 ∼ 4 μm shows agreeable photoluminescence (PL) property and sphericity. The main emission peak appears at about 593 nm, which corresponds to 5D0→7F1 transition (magnetic-dipole transition) of the Eu3+ ion. The cell parameters and powder diffraction data were indexed. The structure of the phosphor belongs to the hexagonal system with space group P63/m.