Effect of Aluminum Polycation Solution on the Morphology and VUV Characteristics of BaMgAl₁₀O₁₇ Blue Phosphor Prepared by Spray Pyrolysis

Spherical BaMgAl₁₀O₁₇:Eu (BAM) phosphor particles with good photoluminescence characteristics under the excitation of vacuum ultraviolet light were synthesized by spray pyrolysis. Two different spray solutions were prepared to see the changes in the morphology and luminance properties of BAM particles. One was an aqueous solution; the other was a polycation solution which was obtained by chemically modifying the aqueous solution with NH₄OH. The BAM particles prepared with the aqueous solution had a porous structure and utterly lost their spherical morphology after post heat-treatment. On the contrary, completely dense and spherical particles were obtained from the polycation solution and their spherical morphology was maintained even after heat-treatment. The dense and spherical BAM particles showed remarkable improvement in photoluminescence intensity compared to that of the hollow particles as well as the commercial one. According to X-ray diffraction analysis, there was no difference in the crystal structures of the two samples. So, the improved photoluminescence comes not from the difference of chemical composition or crystal structure, but from the morphological difference.