掺杂Pb^(2+)对YAG∶Ce^(3+),Pr^(3+)黄色荧光粉中红光发射的影响

Influence of Pb^(2+) Doping on Red Emission of YAG∶ Ce^(3+),Pr^(3+) Yellow Phosphors

在一氧化碳还原气氛下,通过高温固相法合成了YAG∶Ce3+,Pr3+,Pb2+黄色荧光粉。通过X射线衍射和激发、发射光谱对样品进行表征。结果表明:在YAG∶Ce3+,Pr3+荧光粉中掺杂一定量的Pb O,可以使Ce3+的534 nm宽带发生红移,同时Pr3+在610 nm处的红光发射强度增强,这是由于Pb2+的加入影响了晶体场环境,从而导致Ce3+5d能级的重心下移,使Ce3+发射光谱与Pr3+激发光谱的交叠增加,提高了Ce3+-Pr3+能量传递的效率。当掺杂Pb O的浓度为x=0.04时,红移最强,红黄比值最大,有利于提高基于蓝光芯片和YAG∶Ce黄光荧光粉制备的白光LED的显色指数。

Under carbon monoxide reducing atmosphere,YAG∶ Ce3 ＋,Pr3 ＋,Pb2 ＋yellow phosphors were synthesized by high-temperature solid state reaction method. The crystal structures and luminescence properties were studied. The results show that the emission band of Ce3 ＋in YAG∶ Ce3 ＋,Pr3 ＋phosphors shift to long wavelength region with the Pb2 ＋doping. The red emission from Pr3 ＋is enhanced. It may be attributed to the fact that the Pb2 ＋doping can affect the crystal field environment and make the center of gravity of 5d energy level of Ce3 ＋lower,so that the spectra overlap between the emission spectra of Ce3 ＋and the excitation spectrum of Pr3 ＋,which can improve the energy transfer efficiency from Ce3 ＋to Pr3 ＋.When the concentration of Pb O（ x） is 0. 04,the shift of emission spectra of Ce3 ＋and red / yellow ratio reach to the maximal value. Therefore,it is hopeful to improve the color rendering index of white LEDs based on blue chip and YAG∶ Ce yellow phosphor.