Gd_2O_3:Eu荧光粉体的制备及其发光特性

PREPARATION AND PHOTOLUMINESCENCE OF Gd_2O_3:Eu PHOSPHOR POWDER

分别采用溶胶-凝胶/燃烧合成结合法和共沉淀法合成了Gd2O3:Eu粉体,借助X射线衍射、扫描电镜、透射电镜、分光光度计等分析手段,对比研究了两种工艺制备Gd2O3:Eu荧光粉体的物相组成、形貌及荧光特性。结果表明:共沉淀法合成的Gd2O3:Eu为立方相;溶胶-凝胶/燃烧合成法制备的Gd2O3:Eu为单斜相。溶胶-凝胶/燃烧合成法制备的Gd2O3:Eu粉体蓬松、多孔,但存在一定程度的团聚。共沉淀法制备的立方相Gd2O3:Eu粉体在610nm处呈现Eu3+的特征荧光;溶胶-凝胶/燃烧合成法制备的单斜相Gd2O3:Eu的发射波长产生红移,其中最强的2个发射峰起源于Eu3+的5D0→7F2跃迁,分别位于612nm和621nm。两种工艺制备Gd2O3:Eu粉体荧光特性的差异是由Eu3+在这两种粉体中所处晶格结构的对称性差异引起的。

Gd2O3：Eu phosphor powders were prepared by the sol-gel combustion process or the co-precipitation route, respectively. The phase composition, morphology and photoluminescence of the Gd2O3：Eu phosphors were investigated by X-ray diffraction, scanning electron microscope, transmission electron microscope, and spectrophotometry, respectively. The results show that the Gd2O3：Eu powder prepared by the co-precipitation route is a cubic phase, while the Gd2O3：Eu powder directly obtained by the sol-gel combustion process without further calcination is a monocline phase. The as-prepared powders by the sol-gel combustion process are agglomerated and have a fluffy and porous morphology. Co-precipitated Gd2O3：Eu phosphor powders give a characteristic emission at 610 nm. For the Gd2O3：Eu phosphor powders prepared by the sol-gel combustion process, there is a red shift in emission wavelength, and for the others, two emission peaks at 612nm and 621 nm result from the ^5Do→^7F2 transition of Eu^3＋ ions. The discrepancy in emission is attributed to the variation in the Eu^3＋ site symmetry of the lattice structure in powders.