掺铈、钆、铽的三磷酸镧的合成及其光谱

THE SYNTHESIS AND SPECTRA OF LaP_3O_9:Ce,Gd,Tb

本文首次采用溶液沉淀法合成了一系列LaP_3O_9:Ce、Gd、Tb磷光体.经X射线结构分析表明、它们是较纯的LaP_3O_9相,系环状结构,属于正交晶系,其晶胞参数为a=11.19(?),b=8.54(?),c=7.28(?).测定了这些化合物的激发和发射光谱、相对亮度及Ce^(3+)的荧光寿命,观察到在此基质中Ce^(3+)与Gd^(3+)光谱重叠,它们之间存在着一定的相互作用,Ce^(3+)能有效地敏化Tb^(3+),从而大大地增强Tb^(3+)的发射,LaP_3O_9:Ce、Tb可能成为一种新的高效绿色发光材料.在Ce-Tb共掺的体系中加入少量Gd却使发光亮度稍有下降,这可能是由于Gd^(3+)的竞争吸收和独立发射所致.从Ce^(3+)的荧光寿命变化可知,Ce^(3+)对Gd^(3+)的能量传递较弱,而Ce^(3+)对Tb^(3+)则很有效.

A series of LaP3O2: Ce,Gd,Tb phosphors have been prepared by a solution-precipitation method. X-ray structural analysis showed that they are fairly pure LaP3O9 phase, with a cyclic-(PO3)3-structure, belonging to orthorhombic syngong;with cell parameters a= 11. 19,6=8.54,c=7.28A, Their excitation and emission spectra,relative brightness and the luminescence lifetime of Ce3+ have been measured. It was observed that the spectra of Ce3+ overlaps with that of Gd,showing that there is some interaction in energy between these two ion;and Ce3+ can effectively sensitize Tb3+, so as to enhance the emission of Tb3+ significantly. LaP3O9:Ce,Tb might be a new high efficient green emitting phosphor. Adding a small amount of Gd to Ce,Tb codoped LaP3O9 led to the lowering of the emission brightness to a certain extent. This might be due to the competition absoption by Gd3+. From the luminescence lifetime of Ce3+ it can be inferred that the energy transfer from Ce3+ to Gd3+ is weak,whereas that from Ce3+ to Tb3+ is very efficient.