Luminescent properties of SrSi_2N_2O_2:Ce~(3+),Tb~(3+)—a potential phosphor for white light emitting diodes

Abstract: Ce 3+ and Tb 3+ co-doped SrSi 2 N 2 O 2 phosphors were prepared by solid-state reaction. The X-ray diffraction pattern exhibited that the phosphor consisted mainly of oxygen-rich SrSi 2 N 2 O 2 . The optical properties of SrSi 2 N 2 O 2 :Ce 3+ , SrSi 2 N 2 O 2 :Tb 3+ and SrSi 2 N 2 O 2 :Ce 3+ ,Tb 3+ were studied, respectively. The emission intensity of Tb 3+ at 541 nm was remarkably enhanced by Ce 3+ in SrSi 2 N 2 O 2 :Ce 3+ ,Tb 3+ phosphor, which was attributed to the energy transfer from Ce 3+ to Tb 3+ . The chromaticity coordinates of phosphors were investigated as a function of Tb 3+ concentration. When the Ce 3+ and Tb 3+ concentrations were 0.02 and 0.18 mol per formula unit, respectively, the chromaticity coordinate was (0.257, 0.337) in the CIE 1931 chromaticity diagram. SrSi 2 N 2 O 2 Ce 3+ ,Tb 3+ phosphors could be used for white light emitting diodes. Keywords: luminescence; phosphors; white LED; oxynitride; rare earths Oxynitride phosphors have been widely used for white light emitting diodes (WLED) owing to their promising lu-minescent properties and superior thermal stabilities