稀土离子共掺杂的钼酸钙发光材料的合成与光谱性质

Synthesis and Fluorescence Properties of Rare Earth Ions Co-Doped CaMoO_4

采用了化学共沉淀法合成了一系列的镨、铽共掺杂的钼酸钙发光材料,研究了单掺Pr^(3+)和Tb^(3+)以及CaMoO4∶0.03Pr^(3+),yTb^(3+)共掺杂的浓度、温度对材料发光性能的影响。采用X射线衍射仪(XRD)和荧光光谱对样品进行了晶格结构、荧光性质表征。XRD分析表明:样品的主衍射峰与标准卡片(JCPDS 29-0351的衍射峰数据一致,说明少量Pr^(3+)掺杂没有改变基质晶格结构。荧光光谱分析表明,样品在275nm紫外光激发下,发射光谱主要包括多个发射峰,波长为488,560,621和652nm,分别对应于镨离子的~3P_0-~3H_4,~3P_0-~3H_5,~1D_2-~3H_4和~3P_0-~3F_2的跃迁,在掺杂量为3%时,样品特征发射峰最强,CaMoO4∶0.03Pr^(3+)和CaMoO4∶0.05Tb^(3+)的最佳煅烧温度分别为800和600℃。随着Pr^(3+)和Tb^(3+)掺入量的增加,CaMoO4∶Pr^(3+)发光材料的特征发射光谱和激发光谱的特征峰强度逐渐减小,而CaMoO4∶Tb^(3+)材料发光先减小后增大,存在着浓度猝灭效应。此外,在CaMoO4∶0.03Pr^(3+),yTb^(3+)发光体系中,Tb^(3+)的共掺杂可显著增强镨离子的特征发射峰,这是由于存在Tb^(3+)→Pr^(3+)的有效的能量传递。

In this paper,a series of CaMoO4 phosphor co-doped rare earth ions were prepared with chemistry co-precipitation method.The concentration of Pr3＋/Tb3＋and temperature had obvious influence on the luminescent properties.The crystal structures and spectrum characteristics of the samples were identified with X-ray powder diffraction（XRD）and fluorescence spectrophotometer（PL）.According to XRD analysis,the main diffraction peaks of samples are consistent with the standard card（JCPDS 29-0351）of the diffraction peak data.This showed doped rare earth ions did not change matrix lattice structure.The emission spectrum excited by 275 nm exhibit sharp lines peaking at 488,560,621 and 560nm assigned to the 3P0—3H4,3P0—3H5,1D2—3H4 and 3P0—3F2 transitions of the Pr3＋ions.The intensity of fluorescence reached the strongest when the concentration of the doping amount was 3%.The optimum calcination temperatures of CaMoO4∶0.03Pr3＋and CaMoO4∶0.05Tb3＋were 800 and 600 ℃.Furthermore,the intensity of excitation spectra and emission spectra are dependent on the concentration of the doping amount.The emission spectra intensities of CaMoO4∶Pr3＋phosphors decrease and CaMoO4∶Tb3＋phosphors firstly increase and then decrease because of concentration quenching effect with increasing Pr3＋and Tb3＋concentration.In addition,the luminescence properties of Pr3＋ion in CaMoO4∶0.03Pr3＋,yTb3＋system could be evidently improved with co-doping of Tb3＋ions which was due to the efficient energy transfer process from Tb3＋to Pr3＋ions.