Effect of NH4F flux on the characteristics of barium strontium silicate phosphor particles

Abstract

[ <TEX>$Ba_{1.5}Sr_{0.5}SiO_4:Eu$</TEX> ] phosphor particles with high photoluminescence intensity under long wavelength ultraviolet were prepared by spray pyrolysis. We investigated the effect of <TEX>$NH_4F$</TEX> flux added into starting solution on the morphology and photoluminescence intensity of <TEX>$Ba_{1.5}Sr_{0.5}SiO_4:Eu$</TEX> phosphor prepared by spray pyrolysis. <TEX>$Ba_{1.5}Sr_{0.5}SiO_4:Eu$</TEX> phosphor particles prepared from starting solution containing <TEX>$NH_4F$</TEX> flux had the maximum photoluminescence intensity at the post-treatment temperature of <TEX>$1200^{\circ}C$</TEX> and the maximum photoluminescence intensity of <TEX>$Ba_{1.5}Sr_{0.5}SiO_4:Eu$</TEX> phosphor particles prepared from the starting solution containing <TEX>$NH_4F$</TEX> flux was <TEX>$137\%$</TEX> of that of the phosphor particles prepared from the starting solution without flux material. <TEX>$Ba_{1.5}Sr_{0.5}SiO_4:Eu$</TEX> phosphor particles prepared from starting solution containing <TEX>$NH_4F$</TEX> flux had larger size and more aggregated morphology than those prepared from starting solution without flux material. The photoluminescence intensity of <TEX>$Ba_{1.5}Sr_{0.5}SiO_4:Eu$</TEX> phosphor particles prepared from starting solution containing <TEX>$NH_4F$</TEX> flux above <TEX>$3wt.\%$</TEX> had high photoluminescence intensities. The addition amount of <TEX>$NH_4F$</TEX> flux showing the maximum photoluminescence intensity was <TEX>$12wt.\%$</TEX>. The optimum amount of <TEX>$NH_4F$</TEX> flux was <TEX>$5wt.\%$</TEX> when we considered the morphological and photoluminescence characteristics of <TEX>$Ba_{1.5}Sr_{0.5}SiO_4:Eu$</TEX> ohosphor particles prepared by spray pyrolysis.