NaGdF_4:Er^(3+),Yb^(3+)发光粉的水热合成与上转换发光性质

Hydrothermal Synthesis and Upconversion Luminescence Properties of NaGdF_4: Er^(3+),Yb^(3+) Phosphors

采用水热法经不同反应条件合成NaGdF_4:Er^(3+),Yb^(3+)上转换发光粉.通过X射线衍射(XRD)、电子扫描电镜(SEM)和上转换发射光谱对样品进行表征.XRD研究结果表明:稀土离子与Na F的摩尔比例和反应时间对六方结构的Na Gd F_4晶相的形成有影响.SEM研究结果说明:稀土离子与Na F的摩尔比例改变,样品的形貌也随着改变.上转换发射光谱结果表明:上转换绿光与红光分别来自Er^(3+)的~2H_(11/2),~4S_(3/2)与~4F_(9/2)到~4I_(15/2)的能级跃迁产生的,且样品的绿光上转换发射强度强于红光.随着稀土离子与Na F的摩尔比例增大,绿光与红光的上转换发射强度也随着增强,说明不同形貌的样品影响着样品的发光性能.

Upconversion luminescence NaGdF4：Er3＋,Yb3＋phosphors were prepared under different re-action conditions by a hydrothermal method. X-ray diffraction（XRD）,field emission scanning electron microscope（ SEM） and upconversion（ UC） emission spectra were used to characterize the samples. The re-sults of XRD indicate that the formation of hexagonal phase NaGdF4 depends on the molar ratio of rare earth ions to NaF and hydrothermal reaction time. The results of SEM show that morphology of the sample changes with changing molar ratio of rare earth ions to NaF. The results of the upconversion emission spectra show that green emission is from 2 H11/2→4 I15/2 and 4 S3/2→4 I15/2 transitions of Er3＋ions and red emission comes from 4 F9/2→4 I15/2 transitions of Er3＋ions. Green emission intensity is significantly stronger than the red emission intensity for two samples. The ratio of the intensity of green emission to that of red emission increases with increasing the molar ratio of rare earth ions to NaF. All these indicate the upcon-version properties are affected by different morphology.