白光LED用Ca_(8–x)Mg(SiO_4)_4Cl_2:xEu^(2+)荧光粉的制备及应用

Synthesis and Application of Ca_(8–x)Mg(SiO_4)_4Cl_2:xEu^(2+) Phosphors for White LED

采用高温固相法在强还原气氛下合成了Ca_(8–x)Mg(SiO_4)_4Cl_2:xEu^(2+)氯硅酸镁钙荧光粉。通过X射线衍射、荧光光谱和扫描电子显微镜对样品的晶体结构和发光特性进行了表征,探讨了Eu^(2+)掺杂量和助熔剂对发光性能的影响。结果表明:该荧光粉属于面心立方结构、Fd3空间群。样品的激发光谱和发射光谱均为宽带谱,位于451~463 nm范围的激发峰强度最大;在波长为458 nm蓝光激发下样品发射蓝绿光,发射峰在508~511 nm范围。当Eu^(2+)掺杂量为0.13时样品的发光强度最佳;分别加入摩尔分数为0.2%的Ca F_2、Ba F_2、Ba Cl_2助熔剂,能提高荧光粉的激发和发射光谱强度,且加入Ba Cl_2制备的荧光粉的发射光谱强度提高12%。考察了该材料在白光LED中的封装应用性能,结果显示蓝绿色荧光粉能够有效提升白光LED的显色性,显色指数达到95以上。

Eu-doped calcium magnesium chlorosilicate phosphors （i.e., Ca8-xMg（SiO4）4Cl2：xEu^2＋） were prepared by a high-temperature solid state reaction method in a reducing atmosphere. The crystal structure and luminescent properties of the samples were characterized by X-ray diff action, photoluminescence spectroscopy and scanning electron microscopy, respectively. Effects of Eu^3＋-doped amount and flux type on the luminescence performance of the samples were investigated. The results show that the Ca8-xMg（SiO4）4Cl2：xEu^2＋ synthesized belongs to a face-centered cubic structure with space group of Fd3. The excitation and emission spectra of the samples are a broadband spectrum. The excitation peak strength in the range of 451-463 nm is most intense. The phosphor samples emit a blue-green light under the wavelength of 458 nm excitation, and the emission peak appears in the range of 508-511 nm. The maximum luminous intensity is obtained at Eu^3＋-doped amount of 0.13 in mol. The luminous intensity of phosphors is significantly increased after CaF2, BaF2 or BaCI2 of 0.2% mole fraction added as a flux, respectively. The luminescence intensity of the sample with BaCl2 is increased by 12%. The application performance of the materials in white LED is also analyzed. The blue-green phosphors can improve the color rendering properties of the white LED, and the color rendering index can reach 〉 95.