绿色荧光体CaSc_2O_4:Ce^(3+)的共沉淀合成与表征

Synthesis and Characterization of Green-Emitting Phosphor CaSc_2O_4:Ce^(3+) by Co-Precipitation Method

以草酸为沉淀剂,用共沉淀法合成前驱体粉末,然后将前驱体粉末在5%H2+95%N2的还原气氛下煅烧,得到发光性能良好的CaSc2O4:Ce3+荧光粉。应用X射线粉末衍射(XRD)、荧光光谱(FS)、综合热分析(TG-DSC)和扫描电镜(SEM)等测试手段对前驱物及煅烧后的粉体进行表征。结果表明:烧结温度于800℃以上时,都可以得到正交结构的纯相CaSc2O4:Ce3+荧光体;其最大激发和发射波长分别在450和510nm,与高温固相法所得产品的发射波长相同。荧光粉优化的合成条件为:Ce3+的最佳掺杂浓度为1%(摩尔分数),最佳煅烧条件为1100℃煅烧6h。最佳煅烧温度较传统的高温固相法(1600℃)低了约500℃,所得产品的发光强度接近高温固相法的产品。

Ce^3＋ activated CaSc2O4 with strong luminescence intensity and stable properties, caught more and more attention as green phosphor for white-light LEDs. The CaSc2O4：Ce^3＋ precursors were first synthesized by co-precipitation. They were precipitated with oxalic acid, and then heated in a 5% H2 ＋ 95% N2 atmosphere. The phosphor was characterized with X-ray diffraction （XRD）, fluorescence spectroscopy, TG-DSC and SEM. It was found that pure CaSc2O4 phase with an orthorhombic structure could be ob-tained by firing at 800℃. The excitation and emission wavelength peaked at 450 and 510 nm, and the emission wavelength conformed to that from high-temperature solid reaction. The synthesis conditions were optimized according to the luminescence intensity. It was found that the optimized concentration for Ce^3 ＋ was 1%. The samples fired at 1100 ℃ for 6 h gave the strongest emission. Although the firing temperature was much lower than that of solid state reaction, the luminescence intensity of our product was similar to it.