甘氨酸燃烧法合成Sr2CeO4及其发光性质研究

为制备具有优良性能的蓝色荧光粉,首次采用甘氨酸-硝酸盐燃烧法合成了Sr2CeO4,利用热重-差热分析仪、X射线粉末衍射仪、扫描电镜等技术对其形成过程、物相结构、形貌粒度、发光性质进行了研究.结果表明:燃烧后的前驱物经800℃焙烧已有目标产物Sr2CeO4生成,1100℃时可得到较纯正交晶系的Sr2CeO4相.颗粒的形貌为不规则球形,平均粒径在80 nm左右.发光性质研究表明:Sr2CeO4荧光粉的激发光谱是宽带双峰结构,此宽带属于Ce4+的电荷迁移带,两个峰分别位于305 nm和348 nm,后者为主峰.用348 nm紫外光激发样品,发出明亮的蓝光,其发射光谱也是一个宽带,最大峰位于470 nm,此峰属于Ce4+的f→t1g跃迁.发光强度在800~1100℃随温度升高而增强.

Synthesis of Sr2CeO4 by glycine combustion method and its luminescent properties

In order to prepare blue-emitting phosphor with excellent properties,Sr2CeO4 was synthesized successfully by a glycinenitrate combustion process.The reaction process,the phases and structure,the size and morphology,and the luminescent properties of as-synthesized samples were investigated respectively by XRD,SEM and spectrophotometer.The results show that the target occurs when the precursor is calcined at 800 ℃,and the perfect orthorhombic Sr2CeO4can be gained when the precursor is calcined at 1100 ℃.The particles of Sr2CeO4 obtained at 1100 ℃ are nearly spherical in shape,and the mean particle size is about 80 nm.The excitation spectrum of Sr2CeO4 phosphor displays a broad band with two peaks around 305 nm and 348 nm respectively;the latter peak is much stronger than the former one.The broad band is due to the charge transfer(CT) band of the Ce4+ ion.Excited with a radiation of 348 nm,the as-synthesized phosphor emits strong blue-white fluorescence,and the emission spectrum shows a broad band with a peak around 470 nm,which can be assigned to the f→t1g transition of Ce4+.It is found that the emission intensity increases with the calcination temperature from 800 ℃ to 1100 ℃.