Ce、Cr∶YAG微晶玻璃的制备及光谱性能研究

Study on preparation and luminescence properties of Ce,Cr co-doping YAG glass ceramics

目前白光LED在红光波段发射较弱,导致其显色指数偏低,在白光LED用Ce∶YAG微晶玻璃中掺入Cr3+来增强红光波段的发射,从而提高显色指数。通过X射线衍射、荧光光度计、电光源参数测试对样品的晶相、光谱性能及荧光寿命进行了表征。研究了Cr3+对Ce∶YAG微晶玻璃发光性能的影响,并对其增红机理进行了初步的探讨。结果表明基质玻璃在1400℃热处理可析出纯的YAG晶相;Ce∶YAG和Ce、Cr∶YAG微晶玻璃在460nm激发下,在480～650nm产生有效发射,发射光谱中心波长位于530nm;由于Ce3+(2E)-Cr3+(4T)之间的非辐射能量传递,Ce、Cr∶YAG微晶玻璃在688、692和705nm处有红色发射峰,能有效地提高白光LED的显色性能。

At present, the color index of white LED is low due to the weakness of red emission. The red emis- sion and color index of the Ce ： YAG （Ce ： Y3A15O12） phosphor used for white LED have been enhanced by do- ping Cr^3＋. The crystalline phase structure, luminescence properties and lifetime were examined by X-ray dif- fraction （XRD） and photoluminescence spectroscopy, respectively. Effect of Cr^3＋ on properties of the Ce ： YAG glass-ceramics was studied. The principle of enhancement of red emission was also investigated. The XRD results showed that only YAG Crystal have been precipitated in the mother glass after heat treatment. Charac- teristic excitation peak located at 460nm was observed in the excitation spectra of the Ce：AG and Ce, Cr ： YAG glass ceramics, which indicated the glass ceramics could be effectively excited by blue light chip. Abroad emission band center located at 530nm was observed from 480 to 650 nm using blue light chip excitation. There are three red emission peaks located at 688, 692 and 705nm in Ce, Cr ： YAG glass ceramic due to a nonradiative energy transfer from the Ce^3＋ （2E） level to Cr^3＋ （4T） level, which could improve the color rendering index of LEDs.