CaGd_2(MoO_4)_4∶Eu^(3+),Bi^(3+)红色荧光粉的制备及发光性能

Synthesis and Luminescence Properties of CaGd_2( MoO_4)_4∶ Eu^(3+),Bi^(3+) Red Phosphors

采用水热法制备了CaGd_(2-x-y)(MoO_4)_4∶xEu^(3+),yBi^(3+)(x=0.01~2,y=0~0.04)系列红色荧光粉。分别用XRD、SEM和荧光分光光度计对样品的晶体结构、微观形貌和发光性能进行了研究。结果表明,样品荧光粉具有体心四方白钨矿结构,属于I4_1/a(88)空间群,15%Eu^(3+)和1%Bi^(3+)(摩尔分数)的相继掺杂对样品基质晶体结构影响不大。样品粉末颗粒呈类八面体状,粒度比较均一,分散性良好,粒径在3~5μm之间。样品的激发光谱由位于200~350 nm的激发宽带和位于350~550 nm的系列激发峰构成,最强激发峰位于396 nm。发射主峰位于617 nm,对应于Eu^(3+)的~5D_0→~7F_2特征跃迁发射。研究未发现Eu^(3+)的浓度猝灭现象。Bi^(3+)的掺杂能对Eu^(3+)起敏化作用,显著提高样品的红光发射和色纯度,其作用类型为交换交互型,最佳掺杂量y=0.01。

A series of CaGd（2-x-y）（ MoO4）4∶ xEu3＋,yBi3＋（ x =0. 01-2,y =0-0. 04） red phosphors were synthesized by a hydrothermal method. The crystal structure,microstructure and luminescent properties of the samples were studied by the use of XRD,SEM and FL spectrophotometer,respectively. The results reveal that the powders with the doping mole frsction of 15% Eu3＋and 1% Bi3＋hold the structure of body-centered quartet scheelite which belongs to the space groups of I41/a（ 88）. The particles of the sample are relatively uniform and the grain size is 3 to 5 μm. The excitation spectra of the samples are made up of a wide excitation band between 200-350 nm and excitation peaks between 350-500 nm. The strongest excitation peak locates at 396 nm,which indicates the sample can be effectively excited by near-UV light. The strongest emission peak locates at 617 nm corresponding to the5 D0→7 F2 transition of Eu3＋. The concentration quenching phenomenon of Eu3＋is not found in the present study. The dope of Bi3＋can sensitize Eu3＋to significantly improve the red emissionintensity and the color purity of the sample. The best doping mole fraction of Bi3＋is 1%.