LaBO_3中Ce^(3+),Dy^(3+)的发光和能量传递

LUMINESCENCE AND ENERGY TRANSFER OF Ce^(3+),Dy^(3+) IN LaBO_3

研究了在紫外线、阴极射线和X射线激发下,Ce^(3+),Dy^(3+)单掺杂或共掺杂的LaBO_3的发射光谱、激发光谱和其发光强度随组成变化的规律。在紫外线激发下,Ce^(3+)可很好地敏化Dy^(3+)的发光,而在后两种激发下,Ce^(3+)则明显地猝灭Dy^(3+)的发光。研究了在352nm激发下,Dy^(3+)发光强度与浓度的关系,证明Dy^(3+)自身浓度猝灭的机理是电偶极-偶极相互作用。Ce^(3+)→Dy^(3+)能最传递的机理是电多极相互作用为主的共振传递。

In this paper, we present a detailed study of the concentration dependence on luminescent properties of Ce^(3+), Dy^(3+) excited by UV, CR and X-ray in the systems of LaBO_3:Ce, LaBO_3:Dy and LaBO_2:Ce,Dy. The energy transfer from Ce^(3+) to Dy^(3+) and the concentration quenching of Dy^(3+) ~4F_(9/2)→~6H_1(J=15/2, 13/2, 11/2) emissions from UV-excited LaBO_3 host have also been studied.Under the excitation of UV light, the Dy^(3+) emission in LaBO_3:Ce,Dy is well sensitized by Ce^(3+) ion, and comes up to a maximum at about X_(Ce)(molar fraction)=0.08, X_(Dy) (molar fraction)=0.003. Under the excitation of CR or X-ray, the emission spectra of LaBO_3:Dy are similar to that of LaBO_3:Ce,Dy excited by UV light, and get the optimum at X_(Dy)=0.01～0.02, but the Dy^(3+) emission will be quenched by Ce^(3+) ion.In the excitation spectrum of 576 nm emission of Dy^(3+) in LaBO_3:Ce,Dy, we observe the intense characteristic excitation bands of Ce^(3+). It shows that there exists an energy transfer from Ce^(3+) to Dy^(3+). From our experimental data and a discussion using Dexter's theory,, we may conclude that the electrical multipolar interaction is the predominant mechanism for energy transfer from Ce^(3+) to Dy^(3+). Dipole-dipole interaction is the possible mechanism for the quenching of Dy^(3+) emission from the ~4F_(9/2) level which occurs by the cross-relaxation processes ~4F_(9/2)→~6F_(3/2) and ~6H_(15/2)→~6H_(9/2) (or ~6F_(11/2))。