一种新型发红光材料SrGdGa3O7:Eu 3+及其性质研究

 采用高温固相法合成了发红光的荧光粉SrGdGa₃O₇:Eu³⁺。漫反射光谱和激发光谱中Eu^₃₊的电荷迁移带、Eu³⁺离子f→f跃迁以及Gd³⁺离子^8S_7/2→⁶I_7/2的跃迁相互吻合；监测Eu³⁺离子的特征发射，激发谱中有Gd^3+离子的激发线表明存在Gd³⁺→Eu³⁺的能量传递。发射光谱中以⁵D₀→⁷F₂ 跃迁为主，表明Eu³⁺离子所占据的晶体学格位没有对称中心的Cs格位。根据低温下的发射光谱计算了⁷F₁ 和^7F₂ 能级完全解除简并后的每个分裂能级的位置。Eu³⁺的发射发生明显的温度猝灭现象，同时发射谱线的分辨率也逐渐降低。Eu³⁺离子的⁵D₀→ ⁷F₂ 跃迁在不同温度下的荧光衰减曲线相似；随着温度的升高，荧光发射强度衰减越快，但是仍然处于毫秒数量级；⁵D₀ → ⁷F₂ 跃迁是宇称和自旋禁阻的跃迁，所以荧光衰减时间比较长。

A New Phosphor SrGdGa3 O7:Eu 3+ and its Luminescent Properties

Phosphor SrGdGa₃ O₇:Eu³⁺ has been synthesized by solid state reaction at high temperature. The bands of f→f transfer of Eu³⁺ and ⁸S_7/2→⁶I_7/2 transfer of Gd³⁺ appear in the exicitation spectrum,which is consistent with diffuse reflectance spectrum. When monitored by 613 nm,there are ⁸S_7/2→ ⁶I_7/2 and ⁸S_7/2→⁶P_7/2transitions of Gd³⁺,indicating that the energy transfer from Gd³⁺ to Eu^3+ happens. Emission spectrum is dominated by the main lines at 613 nm due to the ⁵D₀→⁷F₂ transition,indicating Eu³⁺ occupies Gd site (Cs)without inversion symmetry. The splitted energy levels of ⁷F₁ and ⁷F₂ have been calculated by emission spectrum at 12 K. Emission intensity of Eu³⁺ decreases gradually with temperature increasing,and the resolution of emission peak also decreases.Decay curves of Eu³⁺ (⁵D₀→⁷F₂) at different temperature are similar and emission intensity decrease with temperature increasing. The lifetime of Eu³⁺ is in the order of millisecond,which is reasonable for the forbidden transfer (⁵D₀→⁷F₂).