Oxonitridosilicate phosphors with compositions of Y 1-x Ce x SiO 2 N (x=0-0.1) were synthesized by a new synthetic route based on a solid state reaction among YSi, CeSi, SiO 2 and Y 2 O 3 compounds at high temperature and high pressure. The photoluminescence properties dependent on Ce concentration and temperature were investigated. Concentration quenching occurred when the doped Ce 3+ concentration was more than 3 mol.%. The emission spectra showed red shifts from 430 to 447 nm with the increased Ce concentration from 0.5 mol.% to 10 mol.%. The quenching temperature was estimated as ～380 K. The chromaticity coordinates of the excitation and emission spectra were stable against the temperature. This study showed these YSiO 2 N:Ce 3+ phosphors the potential applications in the three-RGB phosphor-converted white LEDs.
A series of novel Sm3+-doped LiY(MoO4)2 red phosphors under the UV excitation were synthesized by solid state reaction at 800 oC for 7 h. The data measured by X-ray diffraction(XRD) indicated that the samples were all pure phases of LiY(MoO4)2. Their excitation spectra had a broad band ranging from 250 to 350 nm and several sharp peaks. The centers of the peaks were located at about 365 nm(6H5/2→4D3/2), 378 nm(6H5/2→6P7/2), 406 nm(6H5/2→4F7/2), 420 nm(6H5/2→6P5/2), 442 nm(6H5/2→4G9/2), 471 nm(6H5/2→4I13/2) and 482 nm(6H5/2→4I9/2), respectively. The strongest emission was excited by 406 nm, and the main emissions were located at 568 nm(4G5/2→6H5/2), 610 nm(4G5/2→6H7/2), 649 nm(4G5/2→6H9/2) and 710 nm(4G5/2→6H11/2). Photoluminescence properties were determined for various concentrations of Sm3+-doped LiY(MoO4)2 host, and the luminescence intensity had the best value when x=0.02 in LiY1–x(MoO4)2:xSm3+.
