(Zn1-x,Mgx)2GeO4∶Mn2+的荧光以及长余辉发光性能

摘要

采用高温固相法制备了一系列(Zn1-x,Mgx)2GeO4∶Mn2+(0≤x≤0.25)绿色荧光粉,并研究了Mg离子对(Zn1-x,Mgx)2GeO4∶Mn2+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Mn2+的4T1(4G)→6A1(6S)跃迁.随着Mg离子浓度的增加,(Zn1-x,Mgx)2GeO4∶Mn2+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Mn2+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∶Mn2+中荧光与余辉发光的产生机理.%(Zn1-x,Mgx)2GeO4∶Mn2+ (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∶Mn2+ 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 Mn2+ ion.The emission intensity can be increased by the resonant transfer from a subbandgap state in the host to Mn2+, and the PLE spectra of (Zn1-x,Mgx)2GeO4∶Mn2+ 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 Mn2+.The possible mechanism of the PL and LLP was discussed based on the PL and TL results.