Y2O2S:Yb,Ho上转换发光材料的制备及性能

利用硫熔法制备了不同浓度的Yb和Ho掺杂的Y2O2S:Yb,Ho上转换发光材料。采用X线衍射仪、扫描电镜和荧光光谱仪对粉体的相组成、形貌和上转换发光性能进行表征。结果表明:不同浓度的Yb和Ho掺杂后没有改变Y2O2S的晶体结构;颗粒形貌较为规则,多呈现多面体状,分散性较好,颗粒表面很光滑;在980nm激光激发下,Y2O2S:Yb,Ho呈现出以绿光发射为主的上转换荧光,Yb的最佳掺杂量为8%(摩尔分数),Ho的最佳掺杂量为2%(摩尔分数),Ho3+和Yb3+掺杂浓度可显著影响不同颜色发射峰的强度;对激活离子Ho3+来说,同类离子之间发生能量传递和交叉弛豫行为,导致上转换荧光强度发生猝灭;对敏化离子Yb3+来说,Yb3+吸收能量,以热的形式释放出来,产生杂质猝灭。

Preparation and Properties of Upconversion Luminescent Materials of Y2O2S:Yb,Ho

The upconversion luminescent materials of Y2O2S:Yb,Ho doped with different concentrations of Yb and Ho were prepared by a flux method.The phase composition,morphology and upconversion luminescent properties of the powders were characterized by X-ray diffraction,scanning electron microscopy and fluorescence spectroscopy,respectively.The results show that the crystal struc-ture of Y2O2S is not changed with the doping concentration of Yb and Ho.The particle shape is regular with the most of polyhedron,and the particle surface appears smooth.The particle size distribution is narrower.Y2O2S:Yb,Ho exhibits a green upconversion fluo-rescence under the excitation of 980 nm.The optimum doping concentration of Yb and Ho is 8%(in mole) and 2%(in mole),respec-tively.The intensity of different emission is affected by the doping concentration of Yb and Ho.The energy transfer and cross relaxa-tion behaviors occur between the activate ions of Ho3+,causing the concentration quenching.For sensitization ion of Yb3+,the excess Yb3+ ions absorb energy,which is released as heat,resulting in the impurity quenching.