A series of CaMoO4 phosphors doped with trivalent dysprosium ions （Dy3＋） and lithium （Li＋） were prepared by solid state method at 750 °C for 3 h. X-ray diffraction （XRD） confirmed the crystal structure and quality of phosphors. Scanning electron microscopy （SEM） in- dicated that the phosphors presented good crystalline state, and the crystalline grain sizes were about 0.5–3.0 μm. The emission spectra showed that the phosphors had intense emission at 480 （4F9/2→6H15/2）, 576 （4F9/2→6H13/2） and 660 nm （4F9/2→6H11/2）. Meanwhile, the excited spectra indicated it had intense excitation at 352 （6H15/2→6P7/2）, 390 （6H15/2→4M21/2） and 450 nm （6H15/2→4I15/2）. As a charge compensator, Li＋ ions were incorporated into CaMoO4：Dy3＋ phosphors, which enhanced the PL intensities depending on the doping concentration of Li＋. The optimal molar fraction of Dy3＋ ions in Ca1-xMoO4：xDy3＋, 0.05Li＋ was 0.05.
A novel orange phosphor Eu3+ doped barium zirconate(BaZrO3) was synthesized by conventional solid state reaction method and its crystal structure and luminescent properties were investigated in this paper.The X-ray diffraction patterns(XRD) showed that simple BaZrO3 phase was obtained.Monitoring at 596 nm,the excitation spectrum consisted of a broad band and a series of narrow bands and the stronger excitation peaks located at 275 and 393 nm,respectively.The emission spectrum excited by 393 nm UV light was composed of four narrow bands.The strongest emission was located at 596 nm.The appropriate concentration of Eu3+ was 0.025(molar fraction) for the highest emission intensity at 596 nm.The H3BO3 and ammonium were added as flux and the results showed that 2 wt.% NH4F ions was the optimal flux for BaZrO3:Eu3+.
A series of red phosphors M3BO6:Eu3+(M=La,Y) were synthesized at 1150 oC by conventional solid state reaction method and their luminescent properties were investigated.Structural characterization of the luminescent materials was carried out with X-ray powder diffraction(XRD) analysis.Photoluminescence measurements indicated that the La3BO6:Eu3+ phosphor exhibited bright red emission centered at about 612 nm 626 nm under UV excited.La3BO6:Eu3+ phosphor had better luminescent intensity than Y3BO6:Eu3+ phosphors under the same excitation and measuring conditions.It was shown that the 0.08 mol.% Eu3+ ions in La3BO6:Eu3+ phosphors was optimal.The color parameter indicated that La3BO6:Eu3+ phosphor was a preferable red phosphor for white LED.
A red-emitting CaZrO_(3):Eu^(3+)phosphor has been prepared by solid state reaction and its luminescent properties are studied.The crystal structure is investigated by the x-ray diffraction.Through energy transitions of^(5)Do→^(7)Fj(J=0,1,2,3)in Eu^(3+)ions,the emission spectrum of the phosphor shows a series of narrow bands under near-ultraviolet light and the strongest peak locates at 613nm.The emission intensity of Cai-xZrO_(3):xEu^(3+)phosphor will reach the maximum as the molar concentration of Eu^(3+)is 5mol%.
LI XuGUAN LiAN Jia-YiJIN Li-TaoYANG Zhi-PingYANG Yan-MinLI Pan-LaiFU Guang-Sheng
