Preparation and Properties of Spherical BaMgAl10O17:Eu Phosphor by Multi-step Precipitation Method

Abstract

A spherical <TEX>$BaMgAl_{10}$</TEX> <TEX>$O_{17}$</TEX> :Eu phosphor has been synthesized by a multi-step precipitation route. In order to successfully synthesize the phosphor with spherical shape, the hydrated-alumina particles should be controlled for spherical shape. In this process, the hydroxypropyl cellulose (HPC) was used as a dispersing reagent. This reagent plays an important role in that the particles were controlled to have the uniform size of sub-micron. The final product prepared by the multi-step precipitation method maintained spherical shape with uniform size of 0.4<TEX>$\mu\textrm{m}$</TEX>. It can be seen in X-ray diffraction patterns, formation of the single phase of <TEX>$BaMgAl_{10}$</TEX> <TEX>$O_{17}$</TEX> :Eu phosphor prepared by the multi-step precipitation method at <TEX>$1350^{\circ}C$</TEX>. Also, the emission spectra of spherical <TEX>$BaMgAl_{O}$</TEX> <TEX>$10_{17}$</TEX> :Eu phosphor in the present case was compared with those of commercially-available blue phosphor under VUV (Vacuum Ultra Violet) excitation. The luminescence process of the <TEX>$BaMgAl_{10}$</TEX> <TEX>$O_{17}$</TEX> :Eu phosphor is characterized by the <TEX>$4f^{6}$</TEX><TEX>$5d^1$</TEX>longrightarrow4f<TEX>$^{7}$</TEX> transition (blue) of the <TEX>$Eu^{2+}$</TEX> ion acting as an activating center and the maximum luminescence intensity was obtained by reduction treatment at 145<TEX>$0^{\circ}C$</TEX>.