采用高温固相法制备了一系列(Zn1-x,Mgx)2GeO4∶Mn2+(0≤x≤0.25)绿色荧光粉, 并研究了Mg离子对(Zn1-x,Mgx)2GeO4∶Mn2+的结构、荧光以及长余辉发光性能的影响。Mg离子取代Zn进入Zn2GeO4晶格, 形成(Zn1-x,Mgx)2GeO4固溶体, 并产生了晶格畸变。光谱分析结果表明, 样品中位于533 nm的绿色荧光源于Mn2+的4T1(4G)→6A1(6S)跃迁。随着Mg离子浓度的增加, (Zn1-x,Mgx)2GeO4∶Mn2+样品的激发光谱出现了蓝移现象, 说明Mg离子进入到Zn2GeO4晶格中对其晶格结构产生了影响, 导致(Zn1-x,Mgx)2GeO4的带宽发生改变。发射光谱则表明Mg离子进入Zn2GeO4晶格引起Mn2+的4T1(4G)→6A1(6S)跃迁绿色荧光发光强度的增强。Zn2GeO4基质中的氧空位缺陷陷阱深度由于基质带宽的变化而变深, 样品具有良好的长余辉发光效果。通过热释光谱分析研究了材料中缺陷陷阱的特征, 进一步证实了(Zn1-x,Mgx)2GeO4中缺陷陷阱深度发生改变。根据光谱分析结果给出了(Zn1-x,Mgx)2GeO4∶Mn2+中荧光与余辉发光的产生机理。

(Zn1-x,Mgx)2GeO4∶Mn2+ (0≤x≤0.25) green phosphors were synthesized by the conventional solid-state reaction, and the effect of Mg incorporation on photoluminescence (PL) and long-lasting phosphorescence (LLP) characteristics of Zn2GeO4∶Mn2+ was systematically studied. The emission spectrum shows a broad emission band centered at 533 nm, which can be assigned to the 4T1(4G)→6A1(6S) transitions of Mn2+ ion. The emission intensity can be increased by the resonant transfer from a subbandgap state in the host to Mn2+, and the PLE spectra of (Zn1-x,Mgx)2GeO4∶Mn2+ exhibit a blue shift with the increasing of Mg concentration. Thermoluminescence (TL) spectra indicate that the introduction of Mg into the host deepened the Vo traps, resulting in the enhanced phosphorescence of Mn2+. The possible mechanism of the PL and LLP was discussed based on the PL and TL results.