硼酸盐玻璃中某些稀土离子的浓度效应及其能量传递过程

本文系统地报道了硼酸盐玻璃中Ce3+、Sm33+、Eu3+、Ga3+、Tb3+、Dy3+浓度效应,观察到Eu3+、Gd3+、Tb3+在硼酸盐玻璃中随浓度增加其发光强度增强,而Ce3+、Sm3+、Dy3+当其浓度增加到一定数值后,发光强度反而减弱,初步探讨了不同浓度效应的原因.本文还观察到硼玻璃中某些稀土离子对Eu3+、Tb3+离子发光的敏化作用,及讨论了Gd3+和Eu3+、Tb3+之间的能量传递过程,计算其能量传递的效率和几率.估计了能量传递的规律机理.

STUDY OF CONCENTRATION EFFECTS AND ENERGY TRANSFER PROCESS OF SOME RE IONS IN BORATE GLASSES

RE borate glass is a kind of potentially valuble luminescence material. The luminescence intensities of borate glasses with various concentrations of RE ions (Ce3+, Sm3+, Eu3+, Gd3+, Tb3+, Dy3+) have been measured.In case of Ce3+, Sm3+, Dy3+. it is found that the emission intensities of glasses decrease if the RE ion concentration exceeds a specific value. It may be explained by cross relaxation for Sm3+ and Dy3+. Sometimes non-radiation losses occur due to interaction between two RE ions, when the Ce3+ concentration increases, the probability of energy transfer exceeds that of emission.The concentration quenching occurs at 1mol% of cerium due to Ce3+-Ce3+ transfer followed by transport to killer sites. However in case of Eu3+, Gd3+, Tb3+, concentration quenching was not found in this work. Maybe their critical quenching concentrations are larger than 3mol%.It was found energy transfer from. Pr3+, Gd3+, Sm3+ to Eu3+ and from Ce3+, Gd3+, Dy3+ to Tb3+. The energy transfer from Gd3+ to Tb3+ and Eu3+ was discussed in detail.Fig.3 shows the excitation spectra of Gd3+ and Tb3+ in doubly and singly doped borate glasses. The excitation spectrum of 312nm emission of Gd3+ in borate glass shows 237nm band which correspond to 8S7/2-6I transition (see Fig. 3-c). The excitation spectrum of 542nm emission of Tb3+ in doubly doped (Tb3++Gd3+) borate glass also consists of 273nm band which is heightened with increase of Gd3+ concentration. This indicates that the excitation energy may be transferred from Gd3+ to Tb3+.The efficiency and probabilities of energy transfer from Gd3+ to Tb3+ was estimate from emission intensities of Gd3++Tb3+ doped borate glass. According to the concentration dependence of energy transfer probabilities,we belive that the interaction between Gd3+ and Tb3+ is dipole-dipole interaction,