溶胶-凝胶法合成白色Sr2Al2SiO7：Ce^3＋，Tb^3＋磷光体的研究

Sol-gel processed Ce^3＋,Tb^3＋ co-doped white emitting phosphors in Sr2Al2SiO7

研究溶胶-凝胶法合成Sr2Al2SiO7：Ce^3＋，Tb^3＋白色长余辉发光材料。用X射线粉末衍射鉴定Sr2Al2SiO7晶型结构的形成。通过扫描电镜照片可以观察到合成粉体的微观结构，是由0．5-11μm烧结良好的规则颗粒组成。荧光分光光度测定了光谱特性。Ce^3＋，Tb^3＋共激活的Sr2Al2SiO7白色长余辉材料有4个发射光谱，其中包括：在414nm Ce^3＋的特征光谱和在482，543和588nm Tb^3＋的特征光谱。通过改变激活离子的组成可以观察到Tb^3＋和Ce^3＋之间的能量转移。溶胶-凝胶法合成的磷光体形成晶相更加完全，颗粒直径小、粉体松散，具有更强的发光起始强度和更优异的余辉性能。

Sr2Al2SiO7： Ce^3＋,Tb^3＋ white emitting phosphors were fabricated by the sol-gel method. X-ray powder diffraction （XRD） analysis confirmed the formation of Sr2Al2SiO7： Ce^3＋,Tb^3＋. Scanning electron microscopy （SEM） observation indicated that the microstructure of the phosphor consisted of regular fine grains with an average size of about 0.5-1μm. Luminescence properties were analyzed by measuring the photoluminescence spectra. The resultant （Ce^3＋, Tb^3＋）-codoped Sr2Al2SiO7 phosphors show four main emission peaks： one at 414 nm for Ce^3＋ and three at 482, 543 and 588 nm for Tb^3＋. The emission spectra of the samples with different doping concentrations show that the Tb^3＋ emission is dominantly due to the persistent energy transfer from Ce^3＋. The decay characteristic is better than that prepared by solid-state process in the comparable condition. The codoped phosphor showed long persistence white phosphorescence.