980nm LD激发下稀土掺杂Gd_2Ti_2O_7粉末上转换发光

Upconversion Emission in Rare Earth-Doped Gd_2Ti_2O_7 Excited by 980 nm Laser Diode

用高温固相法分别合成了Er3+/Yb3+,Ho3+/Yb3+,Tm3+/Yb3+离子共掺杂的Gd2Ti2O7粉末,X射线衍射结果表明所制备的粉体为立方相烧绿石结构,TEM电镜照片显示其颗粒平均粒径为3μm。该粉末在980 nm LD激发下,分别发射出中心波长为553 nm绿色和662 nm红色(掺Er3+样品)、545 nm绿色和652 nm红色(掺Ho3+样品)、482 nm蓝色和653 nm红色(掺Tm3+样品)的上转换荧光。上转换发光强度和激发功率的关系研究表明,能量传递和激发态吸收是上转换发光的主要机制。同时对Yb3+-Er3+,Yb3+-Tm3+共掺体系的上转换发光强度"过饱和"现象进行了分析,认为是样品的被激发点的温度升高导致了荧光猝灭现象。

Er3＋/Yb3＋,Ho3＋/Yb3＋,Tm3＋/Yb3＋ co-doped Gd2Ti2O7 powders were prepared by solid reaction at high temperature,and characterized by XRD and TEM.The XRD experiment revealed that RE2Ti2O7 had pyrochlore structure.Under 980 nm LD excitation,the strong upconversion emissions at 553,662 nm（Er3＋）,545,652 nm（Ho3＋）,482,653 nm（Tm3＋） were recorded.The power dependence of the intensity of the above upconversion emission was measured.The ＂supersaturation＂ of upconversion emission intensity in Yb3＋-Er3＋,Yb3＋-Tm3＋ co-doped samples was obtained,and it was explained by the increase of the practical temperature at the irradiated spot.