银纳米线/MoO_(3-X)复合基底的合成及其SERS性能研究

表面增强拉曼散射(SERS)具备单分子检测能力和较高的分辨率,因此受到了广泛的关注和研究.本文首先利用氧化钼(MoO_(3-X))的还原特性,在不使用任何表面活性剂的条件下,以AgNO_3溶液作为合成银纳米线(Ag NW)的银源,通过紫外光催化,在MoO_(3-X)薄膜表面还原获得具有交错重叠结构的Ag NW.为评价合成的Ag NW/MoO_(3-X)复合基底的SERS特性,以罗丹明B作为拉曼标记物进行拉曼信号测量.结果显示,制备的Ag NW/MoO_(3-X)复合结构在电磁增强和化学增强的双重作用下,具有较好的SERS特性,表现出较宽的检测范围和灵敏度.     

Characteristics and mechanism analysis of Fano resonances in Π-shaped gold nano-trimer

Fano interference of metallic nanostructure is an effective way to reduce the irradiation loss and improve the spectral resolution. A Π-shaped gold nano-trimer, which is composed of a gold nanorod and two gold nanorices, is presented to investigate the properties of Fano resonances in the visible spectrum by using the finite element method(FEM). The theoretical analysis demonstrates that the Fano resonance of the Π-shaped gold nano-trimer is attributed to the near-field interaction between the bright mode of the nanorice pair and the dark quadrupole mode of the nanorod. Furthermore, by breaking the geometric symmetry of the nanostructure the line-shape spectrum with double Fano resonances of Π-shaped gold nano-trimer is obtained and exhibits structure-dependent and medium-dependent characteristics. It is a helpful strategy to design a plasmonic nanostructure for implementing multiple Fano resonances in practical applications.