蓝光激发白光LED用深红色荧光粉Ca_(1-x-y)WO_4∶xPr^(3+),yLi^+的制备与表征

Preparation and Characterization of Ca_(1-x-y)WO_4∶xPr^(3+),yLi^+ Deep Red Phosphors for White LEDs Excited by Blue Light

用高温固相法合成了用于白光LED的Ca1-x-yWO4∶xPr3+,yLi+红色荧光粉。用XRD、SEM和荧光分光光度计,对试样的晶体结构、表面形貌和发光性能进行表征。所合成的样品为四方晶系。经预先球磨的样品颗粒比较均匀,粒径较小。荧光粉的激发峰位于440～500 nm的宽带内,主要发射峰位于602,620,651 nm,对应于Pr3+的1D2→3H4、3P0→3H6和3P0→3F2特征跃迁发射,651 nm处的强度最大。同时还研究了Pr3+、Li+的掺杂浓度以及助熔剂的加入对样品性能的影响。实验结果表明,所合成的Ca1-x-yWO4∶xPr3+,yLi+是可用于蓝光芯片激发的白光LED用红色荧光粉。

A series of Ca1-x-yWO4∶xPr3＋,yLi＋ deep red phosphors have been synthesized for white LEDs by high temperature solid state reaction.The crystal structure,surface morphology and spectral characteristics of the samples were investigated by the use of X-ray diffraction（XRD）,SEM and fluorescence spectrophotometer.It is found that the synthesized crystalline powders are tetragonal system CaWO4.The particle size of pre-milling sample is more uniform and smaller than the manual grinded sample.The excitation-peaks are between 440 and 500 nm,and the main emission-peaks are located at 602,620,651 nm（Pr3＋ion of 1D2→3H4,3P0→3H6,3P0→3F2 transition）.The peak at 651 nm has the strongest relative luminous intensity.The effects of doping density of Pr3＋,Li＋,calcining temperature and the addition of flux on the characteristics of luminescence have also been investigated.It shows that the Ca1-x-yWO4∶xPr3＋,yLi＋ can be used as red phosphors for blue light chips based white LEDs.