Sm^(3+)掺杂(Y,Tb)AG:Ce^(3+)荧光粉的制备及光谱性能

Preparation and Photoluminescent Properties of Sm^(3+)-doped(Y,Tb)AG:Ce Phosphors

采用柠檬酸溶胶凝胶燃烧合成法制备了一系列组成的(Y,Tb)3Al5O12:Ce3+,Sm3+荧光粉。通过X射线衍射、荧光光谱研究了不同Sm3+离子共掺杂浓度下(Y,Tb)AG:Ce3+荧光粉的晶体结构及光致发光性能。Rietveld全图拟合(Rietveld method of wholepattern fitting)结果表明:掺杂后样品仍为纯立方石榴石相,随着Sm3+离子共掺杂浓度的增加,样品的晶胞参数增大。在467 nm激发下,激发能由Ce3+离子向Sm3+离子单向传递,从而在617nm处出现红光发射。Tb3+离子取代不利于Ce3+离子与Sm3+离子的能量传递,同时Ce3+离子受更强的晶体场作用及与O2-离子间增强的共价性使发射主峰红移,Sm3+掺杂的TAG:Ce体系中,激发能由敏化剂Ce3+离子向激活剂Sm3+离子的传递路径包括5d→4f2F5/2,7/2(Ce3+)和7F6→5D4(Tb3+)到4G5/2→6H7/2(Sm3+)两部分。

A series of（Y,Tb）3Al5O12：Ce3＋,Sm3＋ phosphors were prepared by a sol-gel combustion method.The crystal structure and photoluminescent property under different Sm3＋ concentrations were investigated.The results by Rietveld method of whole pattern fitting indicate that the structure of all the samples is a cubic garnet.With increasing in Sm3＋ concentration,the lattice constants increase monotonously.The red light emitting centered at 617 nm is the result of the one-way energy transition from Ce3＋ ions to Sm3＋ ions.Tb3＋ ions substitution would go against the energy transition from Ce3＋ to Sm3＋.The yellow light emitting from Ce3＋ ions shifts to a longer wavelength followed the complex effects of the stronger crystal field around Ce3＋ ions and its stronger covalence of chemical bond with O2-ions.Within Sm3＋ codoped TAG：Ce system,the path for the activation energy transfer from the sensitizer Ce3＋ ions to the activator Sm3＋ ions involves transferring from the 5d→4f 2F5/2,7/2（Ce3＋） and 7F6→5D4（Tb3＋） to 4G5/2→6H7/2（Sm3＋）.