NaGd(MoO_(4))_(2)∶Er^(3+),Yb^(3+)发光粉的合成与上转换发光性质

Synthesis and upconversion luminescence properties of NaGd(MoO_(4))_(2)∶Er^(3+),Yb^(3+) phosphors

采用水热法合成了系列NaGd(MoO_(4))_(2)∶Er^(3+),Yb^(3+)上转换发光粉。利用X射线衍射仪、扫描电子显微镜和上转换发光光谱仪等对样品的结构、形貌和发光性能进行表征。结果显示,合成的样品均具有四方晶系NaGd(MoO_(4))_(2)结构;pH对样品的形貌有影响;980nm红外光激发下,NaGd(MoO_(4))_(2)∶Er^(3+),Yb^(3+)上转换发光粉显示来自于Er^(3+)的^(2)H_(11/2)→^(4)I_(15)和^(4)S_(3/2)→^(4)I_(15/2)跃迁产生的绿光发射和4I 9/2→4I 15/2跃迁产生的红光发射。比较各样品的发光强度和绿光/红光相对积分强度比,结果显示上转换发光强度和绿光/红光相对积分强度比与晶粒尺寸、晶粒表面形貌,以及Er^(3+)和Yb^(3+)掺杂浓度有关。讨论了可能的上转换发光过程,并计算了样品的色坐标。

A series of NaGd(MoO_(4))_(2)∶Er^(3+),Yb^(3+) upconversion phosphors were synthesized by hydrothermal method.The structure,morphology and upconversion luminescence properties were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM)and upconversion luminescence spectrofluorometer.The results showed that all the synthesized samples had tetragonal NaGd(MoO_(4))_(2)structure.The pH value had an effect on the morphology of the sample.NaGd(MoO_(4))_(2)∶Er^(3+),Yb^(3+)upconversion phosphors under 980nm infrared excitation showed green emission from_(2)H_(11/2)→^(4)I_(15)and^(4)S_(3/2)→^(4)I_(15)transition and red emission from^(4)I_(9/2)→^(4)I_(15)transition of Er^(3+),respectively.The intensity and the integral intensity ratios of green to red emission of the samples were analyzed.The results indicated that the upconversion luminescence intensity and green/red light ratio were related to the grain size,grain surface morphology,Er^(3+)and Yb^(3+)doping concentrations.The possible upconversion luminescence processes were discussed,and the color coordinates of the samples were calculated.