中文摘要：

采用溶胶-凝胶（Sol—gel）法制备出2％Tm^3＋、0％～98％Yb^3＋（摩尔分数，下同）共掺杂NaYF4蓝色上转换发光粉。Yb^3＋共掺杂促进了Tm^3＋掺杂NaYF4由β相到α相的转变。在976nm半导体激光器（LD）激发下，在430-500nm和620-750nm范围内获得了蓝色和红色上转换发光。随着Yb^3＋共掺杂浓度的增大，蓝色上转换发光强度先增大后减小，当Yb抖共掺杂为20％时获得了最强的蓝色上转换发光。随着LD电压的增大，蓝色上转换发光也逐渐增强。探讨了相应的发光机理。

英文摘要：

The 2mol% Tm^3＋ , 0mol%-98mol% Yb^3＋ codoped NaYF4 blue upconversion luminescence pow- ders were prepared by a simple sol-gel method. Yb^3＋ codoping promoted phase transformation of Tm^3＋ doped NaYF4 from β to α phase. The blue and red upconversion emissions of Tm^3＋-Yb^3＋ codoped NaYF4 were detected by a 980nm semiconductor laser diode （LD） excitation in the wavelengths of 430-500nm and 620-750nm, respectively. The intensity of blue upconversion emission increased and then decreased with increasing Yb^3＋ concentration. The strongest blue emission was obtained for 20mol% Yb%3＋ codoping. The intersity of blue upconversion emissions increased with increasing the pump voltage of LD. The corresponding upconversion mechanism was discussed.