Au@SiO_2@LaF_3:Eu纳米核壳结构的制备及其发光性能

Synthesis and Photoluminescence of Au@SiO_2@LaF_3:Eu Nanocomposite

本文利用化学法合成了Au纳米颗粒、Au@SiO2、以及Au@SiO2@LaF3:Eu的纳米核壳结构,并利用透射电镜、紫外可见吸收谱以及荧光光谱对它们的形貌、吸收和发光性能进行了表征。研究表明:通过控制柠檬酸和氯金酸以及正硅酸乙酯和氨水比例可以对Au纳米颗粒的尺寸以及SiO2层的厚度分别进行调控。当Au纳米颗粒的尺寸和SiO2层厚度增加时,Au表面等离子体共振吸收峰发生红移。在Au@SiO2@LaF3:Eu纳米核壳结构中,Au表面等离子体共振对LaF3:Eu纳米颗粒的发光产生减弱作用。另外,Eu掺杂浓度对Au@SiO2@LaF3:Eu纳米核壳结构的5D0→7F2和5D0→7F1跃迁强度比有很大的影响。

The Au nanoparticles, Au @ SiO2 core-shell nanocomposites, and A @ SiO2 @ LaF3： Eu core-shell nanocomposites were subsequently prepared by the chemical solution route. The morphology, surface plasmon absorption and photoluminescence properties were characterized by transmission electron microscope （TEM）, ultraviolet-visible （UV-vis） absorption and photoluminescenee （PL） spectroscopy. It was indicated that the size of Au nanoparticles and the thickness of the SiO2 layer were tuned by the ratio of citric acid/aurichlorohydric acid, and tetraethyl silicate/ammonia, respectively. With the increase of the size of Au nanoparticles and the thickness of SiO2 layer, the surface plasmon absorption of Au nanoparticles was red-shifted. Moreover, the PL intensity of LaF3： Eu in the Au @ SiO2 @ LaF3： Eu core-sheil nanocomposites was suppressed by the surface plasmon resonance of Au. Meanwhile, the Eu doping concentration greatly influenced on the emission intensity ratio of the 5D0→7 F2 and 5D0→7 F1 of the Au@SiO2 @LaF3 ：Eu core-shell nanocomposites. Besides, the PL of LaF3 ：Eu is different from that of LaF3 ：Eu after coated on the Au@SiO2 core shell nanostructure, which also changed with different doses of Eu in LaF3.