SrGa_2O_4:Eu的合成及其发光性能

Preparation and Luminescent Properties of SrGa_2O_4:Eu^(3+)

采用固相反应法合成了掺杂Eu3+离子的SrGa2O4,用X射线粉末衍射对其结构进行了表征。XRD数据经计算机处理表明:SrGa2O4属单斜晶系,晶胞参数a=0.943nm,b=0.900nm,c=0.839nm,β=89.06°,属P21/c(No.14)空间群。测定了激发光谱和发射光谱,光谱数据表明:SrGa2O4:Eu3+荧光粉的发射主峰在610nm,证明Eu3+离子占据了非反演对称中心的位置。在掺杂Eu3+离子摩尔分数大于1%时,由于晶体场的影响,位于590,610nm附近的2个发射峰均出现劈裂现象,即有2个5D0→7F1(586,597nm)和2个5D0→7F2(609,615nm)发射峰,7F2劈裂出两个分支的强度比例随Eu3+浓度的变化而变化。

The development of fiat panel display devices such as field emission displays（FEDs） and vacuum fluorescent displays（VFDs） requires highly efficient cathodolumi.nescent materials. While many efficient sul- fide-based phosphors have been explored as possible low-voltage phosphors, the volatility of sulfur has prohibi- ted their use in FEDs or VFDs. Sulfide-base phosphors often degrade under high energy electron bombardment due to dissociation of the cation-sulfur bonds. Oxide phosphors offer potential advantage because of their supe- rior stability under electron bombardment and excellent luminescent properties. SrGa2 04 is an attractive oxide phosphor for low-voltage cathodoluminscence applications in VFDs and FEDs. Like other wide bandgap semi- conductors, SrGa204 exhibits a purple emission. Activation with Eu^3＋ ions, the emission shifts to red. The Eu^3＋ doped SrGa204 phosphor was prepared with the conventional solid-state reaction method. The phase com- position was characterized by powder X-ray diffraction. The result shows that the producing powder belongs to monoclinic crystal system with its lattice constants： a = O. 943 nm, b = O. 900 nm, c = O. 839 nm,/β = 89.06°, and with space group P21/c （No. 14）. The excitation and emission spectra were measured. The main peak at 610 nm can be ascribed to the electric dipole transition^5D0-^7F2, which indicates that Eu^3＋ occupies a site lacking inversion symmetry. The peaks at 590,610 nm transition emission split to two peaks ：^5D0-^7F1 （586, 597 nm） and^5Do-^7F2 （609, 615 nm） , respectively, due to the crystal-field in the conditions of mole fraction of Eu^3＋ with more than 1%. The strength ratio of two parts for the splitting peakTF2 can be changed according to the concentration of Eu^3＋ .