稀土离子RE(RE=Pr,Nd,Eu)在Sr_2CeO_4基质中的发光性质

Lminescence of Rare Earth Irons(Pr,Nd,Eu)in Sr_2CeO_4 Host

通过燃烧法合成了Sr2CeO4∶RE材料,研究了Sr2CeO4材料的结晶过程和发光性质及Pr3+,Nd3+和Eu3+稀土离子在Sr2CeO4基质中的发光性能。实验通过燃烧法制得的前驱体在1200℃焙烧2h可得均一的Sr2CeO4相,较传统方法的合成时间大为降低。稀土离子Pr3+,Nd3+和Eu3+的在基质中的少量掺杂(0.02%)均可使Sr2CeO4在475nm左右的特征发射谱峰明显变宽增强,且Eu3+离子的掺杂可使材料在510nm,540nm,610nm左右产生多个明显的稀土离子的特征发射峰。实验合成的发光材料具有良好的发光性能,证明Sr2CeO4材料可作为一种优良的发光材料的基质使用,为寻找新型的发光材料提供了一条新的途径。

Uhrafine lanthanon-doped Sr2CeO4 phosphors have been prepared by nitrate-citrate sol-gel combustion process using 1.1 ratio of nitrate/citrate. Phase evolution of the synthesized powder is determined by XRD. Single-phase Sr2CeO4 crystalline powder is obtained by calcinating the precusor at 1 200℃ for 2 hours and no intermediate phase is observed. Scanning electron microscope （SEM）images of as-synthesized powders showed a foamy, porous agglomeration and a continuous three-dimensional network. The agglomerates ranged in size between 5μm and 10μm, The large agglomerates easily fractured down to small 1μm-2μm in diameter agglomerates. The luminescence characteristics of the phosphor particles depend on the morphology of the particles and other properties including size, erystallinity and defects. The emission spectra of the material were measured and investigated. Under 280 nm UV excitating, the synthesized phosphor particles emission spectra were observed a broad band with maximum at about 475 nm. With the rear ／earth element Pr, Nd and Eu doped in the Sr2CeO4 crystalline, the intensity of maximum emission spectra at about 475 nm had been improved greatly and the width of the peak had been widened. The luminescence properties of Sr2CeO4 can be improved by doped rare earth iron. The emission spectra of sample doped with Eu^3＋ iron was not only can observed a broad band with maximum at about 475 nm but also can observed characteristic emission spectra of Eu^3＋ iron at 610 nm.The host can transfer its exciting energy effectively to rare earth iron Eu^3＋. The fluorescence from the higher excited states can be observed because the muhipolar relaxation probability between Eu^3＋ irons is low. In the end, the researches and application of Sr2CeO4 as the host of luminescence materials were prospected.