Improved thermal resistance of spherical BaMgAl₁₀O ₁₇:Eu blue phosphor prepared by spray pyrolysis

The thermal degradation characteristics of BaMgAl₁₀O ₁₇:Eu (BAM) blue phosphor with spherical shape were investigated. In this work, we developed a strategy that is very simple, but very effective to minimize the thermal degradation of BAM blue phosphor. In order to improve the thermal degradation properties of BAM particles prepared by spray pyrolysis, the as-prepared particles were treated by a two-step post thermal treatment. That is, the particles were treated under a vacuum atmosphere at 400 °C and successively in situ reduced at 1400°C. It was found that the two-step treatment effectively reduces the color shift of the BAM particles, which is known as a big problem generally observed in the fabrication processes of plasma display panels (PDPs). According to FT-IR analysis, the vacuum treatment produced a stable hydrophobic surface which was maintained even after the baking process. For further improving the photoluminescence intensity under VUV irradiation, in this work, the surface of BAM particles treated by the above two-step treatment was modified with alkyl and organosilane groups. As a result, the photoluminescence intensity was enhanced. Therefore, it was concluded that removing the water (OH groups) existing on the surface or in the matrix as well as making a hydrophobic surface are promised to minimize the thermal degradation of BAM particles.