纳米Y2O3:Eu3+的内量子效率和表面钝化效应

采用化学自燃烧方法制备了Eu3 掺杂的Y2O3纳米晶粉末材料,并在制备过程中引入了少量的Ag 离子.计算了Eu3 的5D0能级的发光的内量子效率,发现Ag 离子的加入可以使发光的量子效率最大增加12%.通过发射光谱的测量发现荧光最大可增强约50%,通过X射线衍射(XRD)、透射电子显微镜(TEM)、荧光激发和发射光谱研究证实Ag 离子的引入产生两个方面的作用:(1)是能够部分地消除表面的无辐射中心,使量子效率提高,发光增强;(2)是使激发光能够更有效地到达发光中心,提高激发效率,从而使荧光产额提高.     

Flux and concentration effect on Eu^3＋ doped Gd2（MoO4）3 phosphor

A novel red emitting phosphor Gd2（MoO4）3：Eu^3＋ was prepared by solid reaction, using Gd2O3, Eu2O3 and WO3 as starting matedals and NH4F as flux. The effects of flux content and Eu^3＋ concentration on the crystal structure, morphology and luminescent properties were investigated using XRD, SEM and fluorescent spectrum measurement. The XRD patterns showed that the resultants had the monoclinic structure. With the increase in flux amount, their crystallization significantly improved. The SEM images indicated that the mean size of the phosphor particles was around 2 μm, and agglomeration of the phosphor particles appeared while introducing higher flux amount. The excitation spectra exhibited more intense f-f transitions originating from ground state 7^F0 to upper states 5^L6 and 5^D2 than the charge transfer band. The concentration quenching of Eu^3＋ emission indicated that energy transfer from Eu^3＋ to molybdate host existed even at lower Eu^3＋ concentration.     

Lu2O3:Er3+荧光粉的Judd-Ofelt参数计算

三价稀土离子掺杂透明发光材料的f-f跃迁性质可以根据Judd-Ofelt理论进行研究。对于不透明的粉末材料, 由于不能测量其吸收光谱, 难以采用传统的Judd-Ofelt理论进行计算。针对非透明材料, 本研究提出了一种利用漫反射光谱计算稀土掺杂粉末材料Judd-Ofelt参数的方法：首先, 利用Kubelka-Munk方程将漫反射谱转换为强度为相对值的吸收光谱, 然后计算得到相对Judd-Ofelt参数, 再利用荧光衰减测量对相对Judd-Ofelt参数进行修正, 得到真实的Judd-Ofelt参数。将该方法用于计算固相反应合成的Lu₂O₃：Er³⁺样品的Judd-Ofelt参数, 并把利用吸收截面计算得到的Er³⁺的⁴I_13/2能级的辐射跃迁速率与利用Judd-Ofelt参数计算得到的结果进行了比较, 证明研究提出的计算Judd-Ofelt参数的方法是可行的。