Yb3+-Tm3+共掺钨钼酸盐纳米晶体的发光特性

Luminescence Properties of Tungsten and Molybdenum Acid Salt Nano-crystal Doped with Yb3+-Tm3+

以聚乙二醇为络合剂,采用水热法制备了发光性能优越的Yb3+-Tm3+共掺BaGd2(WO4)0.5(MoO4)0.5纳米晶体。改变稀土掺杂量并生产不同掺杂量的BaGd2(WO4)0.5(MoO4)0.5∶Yb3+/Tm3+。以X射线衍射仪(XRD)、扫描电子显微镜(SEM)及透射电子显微镜(TEM)对样品进行表征。结果表明,BaGd2(WO4)0.5-(MoO4)0.5∶Yb3+/Tm3+纳米晶属四方晶系,粒径在25~40nm之间,使用Hitachif-4500分光光度计分析样品,发现当Yb3+/Tm3+为4∶1、Yb3+离子浓度为6.0%时,BaGd2(WO4)0.5(MoO4)0.5∶Yb3+/Tm3+的发光效率最高。当Tm3+离子发生1G4→3H6跃迁时会产生可见光发射,对应于光谱图中475nm处的蓝光;当Tm3+离子发生1G4→3F4跃迁时产生的可见光发射,对应于光谱图中650nm处的红光。光谱图像及泵浦功率的双对数曲线表明,其中蓝光发射是三光子发射过程,红光发射是双光子发射过程。样品的量子产率接近0.9%。Yb3+-Tm3+共掺BaGd2(WO4)0.5(MoO4)0.5纳米晶体的发光性能优异,具有很高的应用价值。

The up-conversion BaGd 2(WO 4)0.5(MoO 4)0.5∶Yb 3+/Tm 3+nano-crystals were synthesized by hydrothermal method with complexing agent PEG.The structure and properties of luminescent powder were examined by X-ray diffraction(XRD),scanning electron microscope(SEM)and transmission electron microscope(TEM).The crystal structure of the sample was tetragonal system,which characterized by XRD.The results showed that the particle size was between 25-40 nm,which observed by SEM and TEM.The luminescence intensity was the strongest while the Yb 3+doping concentration was 6.0%and C Yb 3+/C Tm 3+=4∶1.The blue emission peak at 475 nm corresponded to 1G 4→3H 6 transition of Tm 3+,and red emission peak at 650 nm corresponded to 1G 4→3F 4 transition of Tm 3+.The lg-lg plots of luminescence intensity and pump power revealed that blue emission peak was the three-photon absorption,red emission peak was the two-photon absorption.The quantum yields of the sample were near 0.9%.The BaGd 2(WO 4)0.5(MoO 4)0.5∶Yb 3+/Tm 3+nano-crystals had excellent luminescent properties,which had high practical application value.