共查询到18条相似文献,搜索用时 218 毫秒
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在金,银纳米粒子表面修饰对巯基苯胺(PATP)分子,对其进行紫外及拉曼光谱性质表征。紫外吸收光谱显示修饰了单分子层的纳米粒子表面等离子体共振发生较大的红移,银粒子位移程度大于金粒子的。其拉曼散射增强效应研究表明,对巯基苯胺b2振动模式的极大增强是由电磁增强和化学增强效应共同决定的。金、银粒子上对巯基苯胺单分子层拉曼散射增强效应的差异主要来自金属与对巯基苯胺之间电荷转移能力的不同。 相似文献
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分别用硼氢化钠和氢气还原法制备了两种不同的银溶胶(I和II),并采用自组装技术将银纳米粒子组装到对巯基苯胺(PATP)修饰的光滑银基底表面,形成银纳米粒子亚单层二维阵列。比较两种阵列中PATP的表面增强拉曼光谱发现,溶胶II所得阵列中的PATP的b2振动得到了较大的增强,即存在较大程度的电荷转移,说明银纳米粒子的性质直接影响了耦联分子的光谱特征。对溶胶Ⅰ进行离心处理,组装,得到的拉曼特征与阵列II类似。就溶胶II的银纳米粒子而言,组装结构中可能形成Ag-N化学键,从而导致更强的氨基与银粒子的相互作用。 相似文献
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利用化学自组装方法,首先在色谱玻璃小瓶的内壁吸附上一层PDDA阳离子聚电解质,然后通过静电吸附作用将带有负电荷的银纳米粒子组装到内壁;比较了不同色谱瓶作为吸附银纳米粒子的载体的优缺点;用紫外-可见吸收光谱监测吸附到玻璃瓶内壁的银纳米粒子的表面等离子体共振峰,跟踪银纳米粒子的组装情况;利用对-巯基苯胺作为探针分子研究了基底的表面增强拉曼散射(SERS)活性。结果表明:所制备的SERS小瓶基底具有良好的SERS活性,并且使用简单,保存时间长,适合SERS现场快速检测的需要。 相似文献
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通过溶胶-凝胶法以四甲氧基硅烷(TMOS)和甲基三甲氧基硅烷(MTMS)作为混合的前体,聚乙二醇(PEG)为致孔剂,制备了具有贯通孔道结构的双孔硅胶整体柱,采用3-巯基丙基三甲氧基硅烷(MTPMS)对硅胶整体柱表面进行巯基化修饰后,分别将金、银纳米粒子组装在整体柱材料表面。利用透射电子显微镜(TEM)、紫外-可见吸收光谱(UV-Vis)、扫描电子显微镜(SEM)对金、银纳米粒子形貌、吸收光谱及组装金、银纳米粒子前后整体柱的形貌进行了表征。以对巯基苯胺(PATP)为探针分子,分别采用波长为633和532nm的激发光作为激发光源,研究金和银纳米粒子修饰的硅胶整体柱的在柱表面增强拉曼光谱(SERS)性能。结果表明,该基底呈现出很强的SERS活性,结合整体柱的分离富集优势将在食品/环境领域现场痕量检测方面具有广泛的应用前景。 相似文献
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We have produced silver particles by the gas-evaporation technique and investigated their SERS activity. The enhancement factor is determined quantitatively by measuring the Raman intensity of copper phthalocyanine molecules deposited onto the particle layer. It is shown that the particle layer is a good SERS enhancer, which yields an enhancement of ~ 4 × 103. It is also shown that a five-fold increase in the enhancement factor is obtained, when the particle layer is coated with a 30 nm silver film. The enhancement presently observed seems to arise from the electromagnetic effects, namely, the excitation of localized surface plasmons for the bare particle layer and that of extended surface plasmons for the silver-coated particle layer. 相似文献
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(FD)~2TD计算金属表面场增强 总被引:1,自引:1,他引:0
本文首次利用依赖于频率的时域有限差分法(FD)2TD来计算隐失波激励下金属粒子表面的场增强。首先,利用(FD)2TD计算了三维球形银粒子的表面场增强,与国外文献[11]中用不同方法对此问题的计算结果进行了对比,结果较为相符,说明我们自己编写的(FD)2TD程序是可信的。然后,利用此程序计算了在全内反射条件下,处于介质板上纳米尺度边长的正三角形银粒子表面的场增强,给出了该正三角形银粒子三角端点存在场增强的所谓"热点"并给出了该处的场增强值随样品距离的变化曲线。 相似文献
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Xiaoqi Fu Fengli Bei Xin Wang Xujie Yang Lude Lu 《Journal of Raman spectroscopy : JRS》2010,41(4):370-373
Graphite oxide (GO) was successfully silylated by 3‐mercaptopropyltrimethoxysilane. The surface‐enhanced Raman scattering spectrum of the silylated GO sheets sandwiched between colloidal silver nanoparticles and silver piece is presented. The Raman signal shows a 104 enhancement compared to that of bulk GO. The large Raman enhancement is most likely a result of electromagnetic (EM) coupling between the colloidal silver nanoparticles (localized surface plasmon) and the silver piece (surface plasmon polariton), creating large localized EM fields at their interface, where the silylated GO sheets reside in this sandwich architecture. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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C.A. Murray 《Journal of Electron Spectroscopy and Related Phenomena》1983,29(1):371-382
We have studied the surface enhanced Raman scattering from molecules adsorbed on thin gold overlayers on silver island films. The Raman scattering of gold cyanide species adsorbed on gold overlayers decreases in intensity with gold overlayer thickness between 0.5 – 10 Å . This intensity decrease is consistent with a simple model which takes into account the damping of the electromagnetic resonances of the silver islands by the absorbing gold overlayer. Implications of these findings for the enhancement of Raman scattering from adsorbates on other metals deposited as overlayers on silver will be discussed. 相似文献
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Electromagnetic interaction of fluorophores with designed two-dimensional silver nanoparticle arrays 总被引:1,自引:0,他引:1
H. Ditlbacher N. Felidj J.R. Krenn B. Lamprecht A. Leitner F.R. Aussenegg 《Applied physics. B, Lasers and optics》2001,73(4):373-377
We study the fluorescence enhancement of dye molecules adsorbed on regular two-dimensional arrays of designed silver nanoparticles.
The silver particles show two orthogonal optical resonances at different wavelengths because of their elongated shape. The
short-wavelength resonance was designed to fit to the absorption maximum of the fluorophore. When the excitation light drives
the short-wavelength resonance, the measured fluorescence intensity is strongly enhanced compared to that for the orthogonal
particle orientation. This shows directly a strong electromagnetic coupling between the nanoparticles and the fluorophore.
Additionally enhanced photochemical bleaching is observed due to the interaction of fluorophores with the particles. Using
a rate model describing the fluorescence enhancement and the bleaching enhancement, an average value for the particle-induced
increase in the radiative fluorescence rate is obtained, together with a lower limit for the averaged particle-induced field
intensity enhancement factor.
Received: 3 July 2001 / Revised version: 3 September 2001 / Published online: 15 October 2001 相似文献
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The surface enhanced Raman scattering (SERS) spectra of piperidine in silver colloid solution, on roughened silver electrode
and on roughened silver electrode modified with silver nanoparticles were studied, and the high-quality SERS spectra of piperidine
on roughened silver electrode modified with silver nanoparticles were obtained for the first time. Surface selection rules
derived from the EM enhancement model were employed to deduce piperidine orientations on the different surfaces. On the basis
of this, two models of piperidine adsorbed on the surface of the silver nanoparticles were built, and DFT-B3PW91/LanL2dz was
applied to calculate the Raman frequencies. It proves that, at higher potential values, the piperidine is perpendicularly
standing on the roughened silver electrode surface though its lone-electron pair, but in silver colloid solution and on the
silver nanoparticles modified silver electrode the piperidine molecular lies flat on the silver surface. In the meantime,
the potential dependent SERS of piperidine on the modified electrode were studied. 相似文献
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A STUDY ON SURFACE-ENHANCED HYPER-RAMAN SCATTERING OF BASIC FUCHSIN ADSORBED ON THE SILVER COLLOID 总被引:1,自引:0,他引:1 下载免费PDF全文
This paper presents the surface-enhanced hyper-Raman scattering (SEHRS) effect of basic fuchsin (BF) adsorbed on the silver colloid. On the basis of the absorption spectra, a new absorption band at 1000nm has been observed in the case of BF adsorption on the silver colloid, The result indicates that surface electromagnetic enhancement also appears at the incident photon frequency in the near-IR region, which plays an important role in the SEHRS signals. The electromagnetic enhancement factor (2.0×l04) is estimated by using electromagnetic model. Additionally, surface-enhanced second-harmonic generation (SHG) effect in the cases of pure silver colloid, silver colloid plus adsorbed molecule and KCl solution has been detected. 相似文献