Influence of Bi2O3 flux in the structural and photoluminescence properties of SrAl2O4:Eu2+ phosphors

Abstract SrAl 2 O 4 :Eu 2+ phosphors with various content of Bi 2 O 3 flux were synthesized and analyzed. It was observed that the crystallinity and the particle size of the phosphors were increased with the addition of Bi 2 O 3 flux. These phenomena are considered to be caused via the melting of the Bi 2 O 3 flux particles during the synthesis of the phosphors. The melted Bi 2 O 3 flux increased the mobility and homogeneity of solid reactants, thereby enhancing the photoluminescence intensity of the phosphors. SrAl 2 O 4 :Eu 2+ phosphors with Bi 2 O 3 as the flux exhibited a broad green emission with a peak at 520 nm. The highest photoluminescence emission intensity was observed when 5 mol% Bi 2 O 3 flux was added into the phosphors. The emission is due to 4f 6 5d→4f 7 ( 8 S 7/2 ) transitions of the Eu 2+ ions. Moreover, Bi 2 O 3 flux extended the application of the ultraviolet excited phosphors toward the blue-light excited phosphors. Nevertheless, the influence of Bi 2 O 3 on the afterglow and the emission color of SrAl 2 O 4 :Eu 2+ phosphors were not significant. This research indicated that Bi 2 O 3 flux is effective flux for synthesizing SrAl 2 O 4 :Eu 2+ phosphors.