纳米Ag@SiO_2核壳结构的表面等离子体共振效应对铕配合物的荧光增强作用(英文)

Surface Plasmon Resonance Enhanced Luminescence of Europium Complexes with Ag@SiO_2 Core-Shell Structure

分别制备了二氧化硅壳层厚度为10、25和80 nm的三种Ag@S O2纳米粒子,合成了铕与不同比例苯甲酸根(BA)的配合物、铕与1,10-邻菲罗啉(phen)及2,2′-联吡啶(bpy)的配合物,并对其进行表征.表征结果推测配合物的组成为Eu(BA)nCl3-n·2H2O(n=1,2,3)、Eu(phen)Cl3·2H2O和Eu(bpy)Cl3·2H2O.配合物的荧光光谱显示,在加入Ag@Si O2纳米粒子后,复合物的荧光强度有不同程度的增加,这可能是由于表面等离子体共振造成的.不同硅壳厚度的Ag@Si O2纳米粒子的荧光增强顺序是25 nm>80 nm>10 nm,这表明二氧化硅核壳厚度约25 nm时有较强的表面等离子体共振效应.此外,在这些复合物中,Eu(phen)Cl3·2H2O复合物的增强效果是最强的,而Eu(BA)nCl3-n·2H2O的增强效果是最弱的.在三个苯甲酸铕配合物中,Eu(BA)3·2H2O的增强效果最弱,其他两个苯甲酸铕复合物增强效果相对较好.原因可能是含氮配合物(Eu(phen)Cl3·2H2O和Eu(bpy)Cl3·2H2O)可以和Ag@SiO2更好地成键,而苯甲酸铕配合物和Ag@Si O2纳米粒子的作用相对较弱.Ag@SiO2纳米粒子有望应用于增强稀土材料的发光.

Three types of Ag@SiO2 nanoparticles with silica shel thicknesses of around 10, 25, and 80 nm were prepared. Europium complexes with benzoate （BA） in different proportions, 1,10-phenanthroline （phen） and 2,2＇-bipyridine （bpy）, were synthesized and characterized. The results suggest that the complexes have the formulas Eu（BA）nCl3-n·2H2O （n=1, 2, 3）, Eu（phen）Cl3·2H2O, and Eu（bpy）Cl3·2H2O. The luminescence spectra of the complexes showed that adding Ag@SiO2 nanoparticles increased the fluorescence intensity. The fluorescence enhancement sequence of the different silica shel thickness Ag@SiO2 nanoparticles was 25 nm＆gt;80 nm＆gt;10 nm, which showed that the local surface plasmon resonance was strongest at the silica shel thickness of about 25 nm. Furthermore, the enhancement effect for the Eu（phen）Cl3·2H2O complex was the strongest and that for the benzoic complex Eu（BA）nCl3-n·2H2O was the weakest in these complexes. For the three benzoic complexes, the enhancement effect of Eu（BA）3·2H2O was the lowest. The nitrogenous complexes （Eu（phen）Cl3 and Eu（bpy）Cl3） could combine with Ag@SiO2 nanoparticles very wel , while the interaction of Eu（BA）3·2H2O with Ag@SiO2 nanoparticles was weaker. Ag@SiO2 nanoparticles are expected to enhance luminescence of rare earth materials.