Eu^(2+)在xMF_2-yYF_3体系中光谱性质及其变化规律

SPECTRAL CHARACTERISTICS AND VARIATION LAW OF Eu(Ⅱ) IN xMF_2 -yYF_3

合成了Eu^(2+)激活的碱土稀土复合氟化物体系xMF_2-yYF_3(x=1,2,3;y=0,1,2,3,4,5;M=Ca,Sr,Ba),系统地研究了Eu^(2+)在该体系中的光谱性质及其变化规律,讨论了影响Eu^(2+)光谱的因素。

The complex fluorides xMF2-yYF3(M = Ba, Sr, Ca;x = 1,2,3; y = 0,1,2, 3,4,5) were synthesized with successive firing of 15-20hr in a stream of high purity argon (0.5 1/min) in the temperature range of 800-900℃.Systematic study was made on the spectral characteristics and variation law of Eu(Ⅱ) in the xMF2-yYF3 system, which can be simultaneously doped with divalent and trivalent rare earth ions and is an important class of materials for laser, phosphor, and upconversion applications. Factors influencing spectrum of Eu(Ⅱ) by the positive ions substituted by Eu(Ⅱ) and the positive ions nearest to Eu(Ⅱ) are discussed. The result shows that the emission wavelength of Eu(Ⅱ) from Ba to Ca is moved to longer one, and that when the content of YF3 is increased the emission wavelength of Eu(Ⅱ) is moved to shorter one. For xBaF2-3>YF3 when x is equal to 1 and y is equal to 2, the f-f transition emission of Eu(Ⅱ) was observed. However, even if y is equal to 5 (x is equal to 1) the f-f transition emission of Eu(Ⅱ) Was not found for xSrF2-yYF3. It is concluded from the discussion that the f-f transition of Eu(Ⅱ)can be brought about by increasing the positive ion nearest to Eu(Ⅱ) which has Smaller ionic radius and higher electric charge for Ba system, The f-f transition of Eu (Ⅱ) can't be observed by this method for Sr System. The f-f transition emission of Eu(Ⅱ)is quenched when x is increased in the system of Ba1-xCaxY2F8 :Eu(Ⅱ), which shows that the f-f transition of Eu(Ⅱ) is influenced by the change of host composition.