SiO_2包覆的银纳米颗粒及其团簇的表面增强荧光效应  

Surface enhanced fluorescence effect of SiO_2 coated silver nanoparticles and clusters

作　　者：张成云 张正龙[1] 韩庆艳 杨超 王鹏 弥小虎 郑海荣[1] ZHANG ChengYun1, ZHANG ZhengLong1, HAN QingYan2, YANG Chao1, WANG Peng1, MI XiaoHu1 , ZHENG HaiRong1(1. College of Physics and Information Technology, Shaanxi Normal University, Xi＇an 710062, China; 2. School of Electronic Engineering, Xi ＇an University of Posts and Telecommunications, Xi ＇an 710121, Chin)

机构地区：[1]陕西师范大学物理学与信息技术学院,西安710062 [2]西安邮电大学电子工程学院,西安710121

出　　处：《中国科学：物理学、力学、天文学》2018年第4期38-47,共10页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：国家自然科学基金(批准号:11574190);中央高校基本科研业务费(编号:GK201701008);博士研究生自由探索项目(编号:2017TS013)资助

摘　　要：在高温条件下以乙二醇为还原剂,制备银纳米颗粒,并用改良的St?ber方法,在银纳米颗粒及其多聚体外面包覆一层8 nm左右的二氧化硅,制备出Ag@SiO_2复合纳米颗粒.二氧化硅壳层的包覆不仅可以调控有机分子和银纳米颗粒之间的距离,避免荧光猝灭,还可以提高金属颗粒的分散性和稳定性,有效地拓展其在生物领域中的应用.利用电子束刻蚀技术在衬底表面做记号,成功标记出单个状态的Ag@SiO_2复合纳米颗粒及其多聚体.以Rh6G为探测分子,系统研究了颗粒尺寸、多聚体聚合程度以及激发光的偏振性质对表面增强荧光效应的影响.结果表明,Ag@SiO_2纳米复合衬底对吸附在其表面的Rh6G分子具有明显的荧光增强作用,且增强效果受到颗粒粒径、团聚程度、分布方式以及偏振性质变化的调控.Composite Ag@SiO_2 nanoparticles are prepared for investigating a metal-enhanced fluorescence effect. Due to the competition between enhanced electromagnetic field intensity and fluorescence emission decay, the distance between the molecules and metal surface is an important surface-enhanced fluorescence factor for enhancing or quenching. This distance can be controlled by the size of the separation-layer, and thus the surface-enhanced fluorescence enhancement can be controlled. To avoid fluorescence quenching and obtain a considerable fluorescence enhancement, SiO_2 shell is used to separate the molecules from the metal surface. The surface modification of metallic nanoparticles by SiO_2 can not only improve the dispersibility and stability of metal particles, but also expanding its application effectively in the biological field. For fluorophores located around metal nanostructures, many factors would affect a fluorescence enhancement effect. Investigation of the enhancement mechanism usually becomes difficult and complicated due to too many variables and factors involved in the enhancement process. In order to systematically study the influence of these factors on fluorescence intensity, single polymer nanoparticles are chosen to be an enhanced substrate. The particle distribution is labeled through electron beam lithography and the surface-enhanced fluorescence spectroscopy of single nanoparticle or cluster is achieved by in-situ measurement method. The influence of metal particle size, cluster property and excitation polarization on the surface enhanced fluorescence is studied by using Rh6G as the probe molecule.Obvious fluorescence enhancement effect of Rh6G molecules at the surface of Ag@SiO_2 is observed with nanocomposite, and the enhancement effect is controlled by the metal core particle size, aggregation property, and the polarization direction of the excitation light.

关 键 词：复合纳米颗粒 表面增强荧光 颗粒尺寸 团簇性质 偏振 

分 类 号：TB383.1[一般工业技术—材料科学与工程]