纳米Gd_2O_3:Eu^(3+)中Judd-Ofelt参数的实验确定  

Judd-Ofelt parameters determined experimentally for nanoparticles Gd_2O_3: Eu^(3+)

作　　者：刘春旭[1] 张家骅[1] 吕少哲[1] 刘俊业[1] 

机构地区：[1]中国科学院长春光学精密机械与物理研究所激发态物理国家重点实验室,长春130033

出　　处：《物理学报》2004年第11期3945-3949,共5页Acta Physica Sinica

基　　金：国家自然科学基金 (批准号 :5 0 172 0 47;10 1740 78;10 2 740 83和 60 3 0 80 0 8)资助的课题~~

摘　　要：报道用Judd Ofelt理论研究立方相纳米晶Gd2 O3:Eu3+ 材料在 77K下的光谱性质 .以几乎不受周围晶场环境影响的5D0 →7F1 跃迁为参考 ,利用5D0 →7F2 和5D0 →7F4 跃迁 ,从实验上确定强度参数Ωλ(λ =2 ,4 ) .发现纳米Gd2 O3:Eu3+ 材料晶场强度参数Ωλ 随纳米晶粒径的变化而改变 ,与体材料相比有显著的不同 .随微晶粒径减小 ,发射能级5D0 的寿命变短、量子效率降低 .这是因为微晶粒径越小 ,量子限域效应越强 ,表体比越大 ,在无序体调制的表面上表面缺陷作用增强而引起的 .对电荷 (Eu3+ O2 - )The spectral properties of nanoparticles Gd 2O 3:Eu 3+ have been investigated by using Judd-Ofelt theory at 77K. Intensity parameters Ω λ(λ=2,4) were calculated using the experimental data of 5D 0→ 7F 2 and 5D 0→ 7F 4 transitions by taking the magnetic dipole transition 5D 0→ 7F 1 as reference. The intensity of the transition is almost completely unaffected by the local environment. It is indicated that intensity parameter Ω λ changes with the variation of diameter of nanoparticles Gd 2O 3:Eu 3+,dramatically different from that of the bulk material.With decreasing diameter of the nanoparticles Gd 2O 3: Eu 3+ from 135 to 15nm,the quantum efficiency of the emitting level 5D 0 reduces from 23.6% to 4.6%. The smaller the diameter of nanoparticles Gd 2O 3:Eu 3+, the bigger the ratio of surface to volume and the more the surface defect.It is the enhancing of the non-radiation channels that results in the decrease of the quantum efficiency. The other two non-radiation channels, charge (Eu 3+-O 2-) transfer state and multiphonon nonradiative re-excitaton, were also studied.

关 键 词：EU^3+ 晶场 跃迁 微晶 实验确定 能级 声子 GD2O3 粒径 增强 

分 类 号：O641[理学—物理化学]