LiBa0.95-yBO3∶0.05Tb3+,yBi3+荧光粉的制备及荧光性质

以硼酸和碳酸盐为原料,用高温固相法制备了可被(近)紫外光(369、254 nm)有效激发的Tb³⁺单掺杂Li Ba1-xBO3∶xTb³⁺(物质的量分数x=0.02、0.03、0.04、0.05、0.06、0.07)及Bi³⁺和Tb³⁺共掺杂LiBa_0.95-yBO₃∶0.05Tb³⁺,y Bi³⁺(物质的量分数y=0.02、0.03、0.04、0.05、0.06、0.07)的2个系列荧光粉,产物的结构和形貌分别用粉末X射线衍射(PXRD)和扫描电子显微镜进行表征。PXRD测定结果表明2个系列的产物均为纯相LiBaBO3。通过对第一系列产物荧光光谱的测定,筛选出发光强度最好的产物,据此确定铽离子的最佳掺杂量;在此基础上制备出铋离子掺杂量不同的第二系列荧光粉。荧光光谱测定的实验结果表明,Tb³⁺/Bi³⁺共掺杂的荧光粉的发光强度好于Tb³⁺单掺杂的荧光粉,这说明Bi³⁺对Tb³⁺有敏化作用;而且随着Bi³⁺掺杂量的增加,产物的荧光强度表现出先增加后减小的趋势,当Bi³⁺的掺杂量y=0.03时,产物的荧光强度达到最大。Bi³⁺和Tb³⁺之间存在偶极-四极相互作用而进行能量传递。系列荧光粉的CIE坐标显示其发光颜色在一定程度上呈现出由绿色光到白光的渐变趋势。

Preparation and Fluorescent Properties of LiBa0.95-yBO3: 0.05Tb3+,yBi3+

Two series of phosphors of Tb³⁺ single doped LiBa_1-xBO₃:xTb³⁺ (molar fraction x=0.02, 0.03, 0.04, 0.05, 0.06, 0.07) and Bi³⁺/Tb³⁺ co-doped LiBa_0.95-yBO₃:0.05Tb³⁺,yBi³⁺ (molar fraction y=0.02, 0.03, 0.04, 0.05, 0.06, 0.07) of which can be effectively excited by (near) ultraviolet at 369, 254 nm light were prepared by high temperature solid state reaction from boric acid and carbonates. The structures and morphology of the samples were characterized by powder X-ray diffraction (PXRD) and scanning electron microscopy. PXRD measurement shows that the products of the two series are pure phase LiBaBO₃. By measuring the fluorescent spectra of the first series of products, the product with the best luminescent intensity was screened out, and the optimal doping amount of Tb³⁺ was determined accordingly; on this basis, the second series of phosphors with different doping amounts of Bi³⁺ were prepared. The experimental results of fluorescent spectra show that the luminescent intensity of Tb³⁺/Bi³⁺ co doped phosphors was better than that of Tb³⁺ single-doped phosphors, indicating that Bi³⁺ sensitizes to Tb³⁺; the fluorescent intensity of the products increased first and then decreased with the increase of Bi³⁺ content, and the luminescence intensity of the products reached the maximum when the doped molar fraction y of Bi³⁺ was 0.03. The energy transfer from Bi³⁺ to Tb³⁺ ions is attributed to the dipole quadrupole interaction. The CIE chromaticity coordinates of the phosphors show that the luminescent color exhibited a gradual trend from green to white in some degree.