EDTA含量对超声辅助合成LaPO_4:(Ce,Tb)体系性能的影响

Ultrasonic-assisted Synthesis LaPO_4:(Ce, Tb) with different EDTA and Their Photoluminescence Properties

本文通过控制EDTA的量超声辅助合成LaPO_4:(Ce, Tb)荧光粉,采用XRD、FT-IR、SEM及PL方法对样品进行了表征。结果显示:在VEDTA=38.33mL,[PO_4^(3-)]/[EDTA]的值为0.6时发光强度最大,属于含磷酸镧和结晶水磷酸镧的复合物,六方晶系球状结构,SEM显示其粒径约为直径约为500 nm,并优先选择102晶面生长。EDTA螯合生成的样品,呈现Tb^(3+)的特征发射5D4–7F_J(J={6,5,4,3}),当V_(EDTA)=38.33mL,发光强度最大,原因可能是EDTA螯合La^(3+)离子,优先的生成LaPO_4,且稳定在比率为1或更高的比率[EDTA]/[PO_4^(3-)]中,当[PO_4^(3-)]/[EDTA]的值为0.6时,[EDTA]/[PO_4^(3-)]远高于1,LaPO_4在紫外区有较强的吸收,故其发光强度最大。该研究有助于进一步开发高效发光的荧光材料。

LaPO4:(Ce, Tb) phosphors were synthesized with different amount of EDTA and characterised by XRD, SEM/EDS, FT-IR, PL to analyze their formation mechanism, and the further study of relationship morphology, structure and performance. It was showed that the globular structure stabilized at [PO43-]/[EDTA] ratios of 0.6 when the volume of EDTA is 38.33 mL with the most photoluminescence intensity of LaPO4:(Ce, Tb) can be formed. The samples are complex with hexagonal of 500 nm containing lanthanum phosphate and crystalline water lanthanum phosphate.The [102] of crystals has priority to grow. All of the samples with different EDTA show Tb3+ characteristic emission, i.e 5D4–7FJ(J={6,5,4,3}), revealing the most intense emission of the sample with VEDTA=38.33 mL among the tested samples. A possible formation mechanism for the fluorescent efficiency enhancement has been proposed. The priority of generated LaPO4, in the [EDTA]/[PO43-] ratio of 1 or higher 1, owing to the LaPO4 with strong absorption in the ultraviolet band, so the luminous intensity is the largest. The results are helpful developing effective phosphor.