980 nm LD激发下稀土掺杂Gd_2Ti_2O_7粉末上转换发光

用高温固相法分别合成了Er~(3+)/Yb~(3+),Ho~(3+)/Yb~(3+),Tm~(3+)/Yb~(3+)离子共掺杂的Gd_2Ti_2O_7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Er~(3+)样品)、545 nm绿色和652 nm红色(掺Ho~(3+)样品)、482 nm蓝色和653 nm红色(掺Tm~(3+)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Yb~(3+)-Er~(3+),Yb~(3+)-Tm~(3+)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.

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

Er~(3+)/Yb~(3+), Ho~(3+)/Yb~(3+) , Tm~(3+)/Yb~(3+) co-doped Gd_2Ti_2O_7 powders were prepared by solid reac-tion at high temperature, and characterized by XRD and TEM. The XRD experiment revealed that RE_2Ti_2O_7 had pyrochlore structure. Under 980 nm LD excitation, the strong upconversion emissions at 553, 662 nm (Er~(3+)) , 545, 652 nm (Ho~(3+)), 482, 653 nm (Tm~(3+)) were recorded. The power dependence of the intensity of the above upconversion emission was measured. The "supersaturation" of upconversion e-mission intensity in Yb~(3+)-Er~(3+) , Yb~(3+)-Tin~(3+) co-doped samples was obtained, and it was explained by the in-crease of the practical temperature at the irradiated spot.