Na_3GdSi_2O_7:Tb^(3+)荧光粉发光特性及Gd^(3+)→Tb^(3+)之间的能量传递

Luminescent Properties of Phosphor Na_3GdSi_2O_7:Tb^(3+) and Gd^(3+)→Tb^(3+) Energy Transfer

采用高温固相法合成了Na3Gd1-xTbxSi2O7(x=0.01,0.02,0.04,0.06,0.08,0.1)系列荧光粉。研究了荧光粉的真空紫外-可见发光光谱和荧光寿命,讨论了Tb3+在扭曲八面体结构(标示为Gd(1)3+)和正三棱柱构型(标示为Gd(2)3+)两种格位中的最低5d轨道能级。同时研究了Gd3+→Tb3+之间无辐射能量传递速率K和无辐射能量传递效率η。研究结果表明:Tb3+在Gd(1)3+格位中的最低允许跃迁和禁戒跃迁的5d轨道能级分别位于235 nm和280 nm,在Gd(2)3+格位中的最低允许跃迁和禁戒跃迁的5d轨道能级分别位于224nm和256 nm。随着Tb3+浓度的增加,能量传递效率及速率显著增大,说明在Na3Gd1-xTbxSi2O7中存在有效的Gd3+-Tb3+能量传递。

Tb3+ doped sodium gadolinium pyrosilicate phosphors Na3Gd1-x TbxSi2O7 were prepared using a high-temperature solid-state reaction technique.The spectroscopic properties of Na3Gd1-x Tb x Si2O7 in VUV-UV-Vis range and fluorescent lifetimes were investigated.The lowest 5d orbitals of Tb3+ in two sites both 6-fold distorted octahedron coordination(trigonal antiprism tap)(Gd3+(1)) and 6-fold regular trigonal prism coordination(tp)(Gd 3 +(2)) were discussed.The lowest 5d orbitals of Tb 3+ in Gd3+(1) is 235 nm for allowed transition,and 280 nm for forbidden transition.The lowest 5d orbitals of Tb3+ in Gd 3+(2) is 224 nm for allowed transition,and 256 nm for forbidden transition.The nonradiative energy-transfer rate K and energy-transfer efficiency η were also investigated.The results show that there is efficient Gd3+-Tb3+ energy-transfer in Na 3Gd1-xTbxSi2O7,for K and η increasing with the increasing of Tb3+ concentration.