Fabrication of Silver Nanowires with Corrugated-Surface and Its SERS Performance

Abstract

In order to create the effective number of surface-enhanced Raman scattering (SERS) active "hot spots" on the one-dimensional nanostructure surfaces for ensuring the maximum enhancement of SERS signal, smooth silver nanowires (Ag NWs) were firstly synthesized by the conventional polyol method, and then the smooth silver nanowires were subjected to chemical etching by the Fe(NO 3 ) 3 aqueous solution at room temperature to obtain corrugated silver nanowires. This corrugated silver nanowires were systematically characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) microscopy, Ultraviolet-visible (UV-vis) extinction spectroscopy and surface enhanced Raman spectroscopy (SERS). The SEM image of smooth silver nanowires shows that had a diameter of ca. 120 nm and lengths of about tens of micrometers, while the average thickness of corrugated nanowires was only about 100 nm. The XRD patterns for both smooth and corrugated silver nanowires indicate that the fcc structure was preserved after chemical etching. From the measurement of UV-vis spectra we can see that after the smooth silver nanowires were subjected to chemical etching, only one broad surface plasmon peak was observed at ca. 386 nm while two significant peaks were observed at 353 and 392 nm for the smooth silver nanowires. The slight blue-shift of this peak from 392 to 386 nm could be contributed by the decrease in diameter of silver nanowires, whereas the broadening of the plasmon peak was probably a result of increased surface roughness. The SEM images showed that the surface roughness of silver nanowires was dependent on the amount of Fe(NO 3 ) 3 , by increasing the amount of Fe(NO 3 ) 3 added into the silver nanowires solution, the surface of silver nanowires become more and more rough. However, as the excess amount of etchant added, most silver nanowires would broke off into shorter rods, and even spherical particles. Raman analyses of crystal violet (CV) indicated that the SERS intensity changes depending on the surface roughness of etched silver nanowires, and the silver nanowires with corrugated surfaces exhibited higher enhancement of SERS signal than the smooth silver nanowires. In addition, the SERS detection of CV and 4-mercaptopyridine (4-Mpy) molecules exhibited high detection sensitivity and the detection concentration were as low as 10 -10 and 10 -9 mol/L, respectively, which means that the corrugated silver nanowires could be an efficient SERS active substrate.

Nanostructure formation via post growth of particles

“…3). The small PbSe NPs are encapsulated by six [100] facets and eight [111] facets, their polarities are different due to the difference in electronegativities between Pb and Se and their termination manner (Fig. 39 The driving force of oriented attachment is similar to Ostwald repining; the high energy surface tends to vanish by attachment instead of the elimination of whole NPs.…”

“…For instance, the proper amount of the Cd precursor and S precursor are alternately injected into a reaction mixture containing CdSe seeds to generate uniform CdS shells. 100 In short, post growth of NPs in very different growth conditions will lead to exceptional structures. The less active precursor inhibits homogeneous nucleation.…”

“…Taking the attachment of PdSe as an example, 41 the dipole moment between NPs is vital for the attachment mechanism. The small PbSe NPs are encapsulated by six [100] facets and eight [111] facets, their polarities are different due to the difference in electronegativities between Pb and Se and their termination manner (Fig. 4c, d).…”

Controlled Synthesis of GaSb Nanowires Based on CVD-grown and Their Optical Characterization

“…同时, 通过对得到的多种光谱进行系统表征, 获知 了 GaSb 纳米线的结晶品质, 进而可为优化 GaSb 纳米线 的生长条件提供技术参考 [6] . 经试验表明, 合理调整生 DOI: 10.6023/A16060298…”

Nondestructive Detection of Chlorpyrifos in Apples Based on Surface Enhanced Raman Scattering

“…表面 增强拉曼光谱(Surface Enhanced Raman Spectroscopy, SERS)方法能显著提高拉曼信号的强度, 可在分子水平 上给出丰富的结构信息, 因此采用 SERS 技术检测化学 成分成为近几年的研究热点 [9] . 拉曼光谱表面增强的效 果与表面增强剂的种类密切相关, 其中以金和银的纳米 粒子效果最好, 相比金纳米粒子, 银纳米具有较强的表 面等离子共振效应(SPR) [10] , 其表面增强效果更显著, 其增强系数为金纳米粒子的 10 至 100 倍, 甚至更高 [11] , 本文中以盐酸羟胺还原法制备的银溶胶, 其制备过程简 单, 无需加热, 可直接用于拉曼信号的增强, 且具有较 好的稳定性.…”