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采用金属醇盐法制备MgAl2O4前驱体,通过高温煅烧2～4 h得到纯相MgAl2O4粉体,再将其与YAG∶Ce荧光粉均匀混合,利用热压烧结并结合热等静压处理得到MgAl2O4/Ce∶YAG透明陶瓷。利用X射线衍射、紫外-可见分光光度计等测试手段对样品进行表征。样品由MgAl2O4和YAG两相组成,在340 nm和475 nm有两个激发峰。发射光谱在533 nm有一宽峰,属于Ce3+的5d→4f特征跃迁发射。该透明陶瓷封装蓝光芯片所得白光LED器件在35 mA驱动下的发光效率为133.47 lm.W-1,其寿命及色温稳定性优于采用传统方式封装的白光LED。实验结果表明MgAl2O4/Ce∶YAG透明陶瓷是一种可用于白光LED的新型荧光材料。
The MgAl2O4 precursor was prepared by metal alkoxide method and calcined at high temperature for 2 ~ 4 h to obtain pure MgAl2O4 powder. The pure MgAl2O4 powder was then uniformly mixed with YAG: Ce phosphor by hot isostatic pressing and hot isostatic pressing to obtain MgAl2O4 / Ce: YAG transparent ceramic. The samples were characterized by X-ray diffraction and UV-visible spectrophotometer. The sample consists of two phases, MgAl2O4 and YAG, with two excitation peaks at 340 nm and 475 nm. The emission spectrum has a broad peak at 533 nm and belongs to the 5d → 4f transition of characteristic emission of Ce3 +. The white LED device obtained from the transparent ceramic package blue chip has the luminous efficiency of 133.47 lm.W-1 driven by 35 mA, and has better lifetime and color temperature stability than the traditional white LED package. The experimental results show that MgAl2O4 / Ce: YAG transparent ceramic is a new type of fluorescent material that can be used for white LED.