Mg_3(AlEu)层状氢氧化物的结构与发光性能的研究

Study on Structure and Photoluminescent Property of Mg_3(AlEu) Layered Double Hydroxides

本文采用共沉淀法合成了一系列不同Eu3+含量的Mg-Al-Eu三元层状复合金属氢氧化物(LDH)。采用X-射线衍射(XRD)、红外光谱(IR)、光致发光光谱(PL)以及热重(TG-DTG)对产物进行表征,发现LDH中Eu3+/Al3+物质的量百分比小于25%时,三元LDH中Eu3+含量的增加对其结晶性没有明显的影响;当Eu3+/Al3+物质的量百分比达到25%时,其结晶质量明显变差。PL分析结果表明,所有样品中出现典型的Eu3+5D0-7FJ(J=1,2,3,4)跃迁所致的红光发射。随Eu3+含量的增加,Eu3+的发射强度明显呈增强趋势;当Eu3+/Al3+物质的量百分比达到25%时,其发射强度明显减弱。由此可知,Mg-Al-Eu LDH结构中,Eu3+/Al3+最佳物质的量百分比为20%。

A serial of Mg-Al-Eu ternary layered hydroxides with different Eu3＋ contents were synthesized by coprecipitation. The products were characterized by X-ray diffraction （XRD）, Fourier transform infrared （Fr-IR） spectra, thermogravimetric and differential thermogravimetric （TG-DTG） analyses, and photoluminescence （PL）. Results indicate that the crystallinity of the products is no obvious changes as the Eu^3＋/Al^3＋ molar percentage is in the range of 5% - 20% ; Up to 25%, the crystallinity of the products get poor. PL spectra show that the intensity of Eu^3＋ emission due to SDo-7FJ（J = 1, 2, 3, 4） transition increases as the Eu^3＋/Al^3＋ molar percentage increases from 5% to 20%, beyond 20% the luminescence intensity markedly decreases. The optimal value of the Eu^3＋/Al^3＋ molar percentage is 20%.