Luminescent properties of SrSi sub(2)O sub(2)N sub(2):Eu super(2+) by the two-step synthesis

SrSi sub(2)O sub(2)N sub(2):Eu super(2+) phosphors were synthesized by a high temperature solid-state reaction method using Sr sub(2)SiO sub(4) as the precursor. The effect of different Eu valence and partial substitution of Sr super(2+) by Ba super(2+) in Sr sub(2)SiO sub(4) on the luminescence properties of SrSi sub(2)O sub(2)N sub(2):Eu super(2+) was studied. Phase characteristics and luminescence properties of the samples were investigated in detail by mean of X-ray diffraction and fluorescence spectrophotometer analysis. The results revealed that there exist charge defects originated from the replacement of Sr super(2+) by Eu super(3+) in Sr sub(2)SiO sub(4):Eu super(3+) and anion vacancies which likely occur in Sr sub(1.95)Ba sub(0.05)SiO sub(4):Eu super(2+) due to partial substitutions of Sr super(2+) by Ba super(2+). The defects in the Sr sub(2)SiO sub(4) play a role in luminescence properties of SrSi2C>2N2:Eu super(2+). The emission intensity of the samples that use Sr sub(2)SiO sub(4):Eu super(3+) and Sr sub(1.95)Ba sub(0.05)SiO sub(4):Eu super(2+) as precursor was increased by 17% and 11% respectively when compared with that of using Sr sub(2)SiO sub(4):Eu super(2+) as precursor(0.5 mol% Eu super(2+) concentration). And with the increasing Eu super(2+) concentration, the increasing degree of luminescence intensity of the samples declines rapidly. In additional, at 200 [degrees]C, 75-78% emission intensity of the phosphors measured at room temperature were maintained. Furthermore, partial replacement of Sr super(2+) by Ba super(2+) in samples can reduce thermal quenching.