助熔剂在硅酸盐荧光粉中的应用及分析

Application and Analysis of Fluxes in Silicate Phosphors

以硅酸盐为基质的白光LED用荧光粉,具有原料丰富、成本低廉、合成工艺简单、组成多样、发光可调等优点,是当前研究的热点。助熔剂在硅酸盐荧光粉制备过程中起到了至关重要的作用。本文介绍了硅酸盐荧光粉体系中助熔剂的使用情况,助熔剂类别和用量对荧光粉的晶相、发光强度和形貌都有一定的影响。添加不同的助熔剂以及同类不同量的助熔剂会使硅酸盐荧光粉形成不同的晶相种类;助熔剂阳离子围绕在激活剂离子周围,引起发光中心的数量变化,从而改变发射光谱形状并能很大程度提高发光强度,但是过量的助熔剂则会降低荧光粉的发光强度;助熔剂用量对荧光粉表面形貌影响明显,适量的助熔剂能细化晶粒,使晶粒尺寸均匀,晶粒球化,但是助熔剂过量则会使样品结块。加强荧光粉制备过程中助熔剂的机理研究,选择合适的助熔剂及其用量,是合成高性能荧光粉的关键。

Silicate based phosphors for white LED have many advantages,such as abundant raw materials,low cost,simple synthesis process,composition diversity,adjustable luminescence,and so on.And it is extensively investigated in recent years.Fluxes play an important role in the preparation of silicate phosphor.This paper introduces the use of fluxes in silicate phosphor system.The type and amount of fluxes have some influence on the crystal phase,luminous intensity and morphology of phosphor.The results show that adding different fluxes and the different amount of fluxes can make silicate phosphors form different types of crystal phase.The fluxes cation around the activator ions causes the number of luminescence centers to change,which can change the shape of the emission spectrum and greatly improve the luminous intensity,but excessive fluxes will reduce the luminous intensity of the phosphors.The effect of flux on the surface morphology of phosphor is obvious.Appropriate flux can refine the grain,make the grain size uniform and spheroidize,but excessive flux will make the sample agglomerate.The key on the synthesis of high performance phosphors is to strengthen the study on the mechanism of flux in the preparation of phosphors,and to select the appropriate flux and its dosage.