发光二极管用荧光粉Sr_(2-x)Ba_xSiO_4:Eu的制备、发光性能及应用

PREPARATION,LUMINESCENCE AND APPLICATION OF Sr_(2-x)Ba_xSiO_4:Eu PHOSPHOR FOR LIGHT-EMITTING DIODES

采用高温固相法制备了发光二极管(light-emitting diode,LED)用硅酸盐荧光粉Sr2–xBaxSiO4:Eu。用热重–差热分析、X射线衍射和扫描电镜对荧光粉进行了表征,讨论了碱土元素锶钡的含量对激发光谱与发射光谱的影响。结果表明:在还原气氛下,1245℃反应3h能得到发光性能较好的荧光粉;荧光粉中锶钡的含量对其发射光谱及激发光谱有较大影响,随着荧光粉中钡含量的增加,发射峰及激发峰位置逐渐蓝移,强度也逐渐增强;并用晶体场强及共价性对其进行了讨论。该荧光粉颜色可调,可用于紫外、近紫外、蓝色LED的封装。

Alkaline earth orthosilicate Sr2-xBaxSiO4：Eu phosphors for light-emitting diode （LED） were prepared by the solid-state reaction method. The synthesis conditions and the morphology of phosphors were investigated by thermogravimetry-differential thermal analysis, X-ray diffraction and scanning electronic microscopy. The influence of Sr and Ba content in Sr2-xBaxSiO4：Eu on the shape and peak positions of the excitation and emission spectra was investigated. The results show that Sr2-xBaxSiO4：Eu phosphor with excellent luminescence properties can be obtained by calcination at 1 245 ℃ for 3 h under reduction atmosphere. The Sr and Ba content in Sr2-xBaxSiO4：Eu plays an important role in the shape and peak positions of the excitation and emission spectra. The increasing of Ba content results in a blue shift of the excitation and emission peaks, and the excitation and emission intensities are increased. This can be attributed to the two competing factors of the crystal field strength and covalence. The colors of the phosphors are adjustable, and they can be employed as a color-ttmable phosphor for white LED pumping with ultraviolet, near-ultraviolet and blue light LEDs.