Al_2O_3/蒙脱土:Eu^(2+)架状结构发光材料的制备及发光性能研究

Preparation and Luminescence Properties of Eu^(2+) Doped Alumina /Montmorillonite Materials with Frame Structures

采用高温固相法,在还原气氛下制备出Al2O3/蒙脱土:Eu2+光致发光材料。研究了原料配比、烧结温度、保温时间以及激活剂Eu2+的含量对发光性能的影响。实验结果表明:加入蒙脱土后,所制备的样品仍保持Al2O3的架状结构,晶格常数发生变化,晶体产生畸变,使得Eu2+更容易进入到晶格中。荧光光谱分析显示,发射光谱是两个宽峰组成,对应于Eu2+的4f65d→4f7(8S7/2)宽带允许跃迁。发光机制分析认为,宽峰结构由Eu0.92[Al1.76Si2.24O8]新相产生,生成的新相增加了Eu2+的取代格位,形成新的发光中心。因此Eu2+不仅取代了Al2O3八面体中Al的格位,而且取代了蒙脱土层间所吸附的阳离子格位,使样品发光强度提高了220%。

A photoluminescent material of Al2O3/ montmorillonite： Eu^2＋was prepared via the solid-state reaction under the reducing atmosphere at high temperatures. The influences of the ratio of raw materials,sintering temperatures,duration and the content of activator on the luminescence properties were studied. The results showed that the frame structure of Al2O3maintained nearly unchanged but the crystal lattice parameters were different by adding montmorillonite. It made the Eu^2＋more easily into the lattice due to this crystal distortion. The fluorescence spectra analysis revealed that the emission spectroscopy consisted of two broad peaks,corresponding to 4f^65d→4f^7 broadband allowed transition of Eu^2＋. The luminescence mechanism analysis indicated that the broad peak structure was generated by the new phase of Eu0. 92[Al1. 76Si2. 24O8],which would increase the substitution site Eu^2＋,forming a new luminescence centers,therefore Eu^2＋would not only replace the Al sites in the Al2O3octahedral structure,but also replace the cations sites between the montmorillonite layers,and resulted in the luminescence intensity of specimens in increasing to 220%.