共查询到19条相似文献,搜索用时 217 毫秒
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微波法制备银胶体及其在表面增强拉曼散射中的应用 总被引:3,自引:2,他引:3
本文提出了一种利用微波加热的原理,合成一种新型的银胶体溶液。该银胶具有高效的表面增强拉曼活性。以这种新型银胶体粒子作为活性衬底,测得的强荧光物质R6G的表面增强拉曼光谱,体现出荧光背景低,信噪比高的特点。通过两种不同方法制备的银胶体粒子的表面增强拉曼散射效果的比较,发现这种新型银胶纳米粒子通过聚集,形成更多的具有很强的提高样品表面增强拉曼散射强度作用的“热点”,从实验的角度验证了表面增强拉曼中的“热点”理论。 相似文献
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以新型银胶为衬底的超低浓度R6G的拉曼光谱检测 总被引:5,自引:3,他引:2
利用柠檬酸钠还原硝酸银的原理,提出了一种微波加热制备银胶体粒子的新方法,得到了颗粒大小较均匀的灰色银胶体。以提纯后的银胶为表面增强拉曼散射衬底,研究了超低浓度染料大分子罗丹明6G分子的表面增强拉曼散射,得到浓度分别为10-12mol/L、10-13mol/L和10-14mol/L的罗丹明6G的表面增强拉曼散射光谱,初步实现了罗丹明6G的单分子检测,证明该新型银胶衬底有非常强的表面增强拉曼活性。同时根据表面增强拉曼散射“热点”的增强机理,分析了获得超低浓度R6G的表面增强拉曼光谱的原因。 相似文献
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银纳米粒子阵列的自组装及其表面增强拉曼光谱应用 总被引:5,自引:0,他引:5
在以聚赖氨酸为表面耦联层分子的玻片基底制备了银纳米粒子阵列。SEM表征结果表明,银粒子以亚单层的形式排列在基底表面。比较银溶胶和纳米粒子阵列的紫外可见光谱可见聚赖氨酸耦联层对银纳米粒子的粒径具有一定的选择性,甲基紫精在银纳米粒子阵列上的表面增强FT拉曼光谱表明在近红外区拉曼散射的表面增强主要来自于化学增强效应。 相似文献
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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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在室温下,以硝酸银为银源,抗坏血酸为还原剂,通过调节表面活性剂聚乙烯吡络烷酮的浓度,实现对花状银纳米颗粒的可控制备。利用扫描电子显微镜、原子力显微镜、X射线衍射和X射线能谱等手段检测并分析了材料的形貌结构和成分组成。实验结果表明,当聚乙烯吡络烷酮的浓度为0.1 mol/L时,所制备花状银纳米颗粒的表面结构达到最精细的状态且颗粒的尺寸达到微米量级,适合对单颗粒进行定位与光学性质研究。以结构最优化的花状银纳米颗粒为表面增强拉曼散射基底材料,以羟基苯甲酸为探针,对单个和少数颗粒的表面增强拉曼散射效应进行了研究,并借助暗场散射光谱分析了基底的表面增强拉曼散射机理。结果显示,该花状银纳米颗粒因其独特的表面结构为拉曼信号增强提供了大量“热点”。良好的拉曼性能以及较低的制备成本表明,该新型表面增强拉曼散射基底具有很大的应用前景。 相似文献
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《光子学报》2018,(11)
理论设计了介质光栅/金属薄膜与银纳米立方体复合结构,通过有限元方法数值模拟计算了该结构中的超高电场增强因子.使用442nm波长的激光作为表面等离子体的激发光源,研究不同尺寸银纳米立方体的消光谱以及不同光栅周期和厚度的反射光谱,得到的该复合结构的最优参数为:光栅周期312nm,厚度90nm,银纳米立方体70nm.在最优参数条件下,数值模拟了复合结构中的电场增强分布,介质光栅/金属薄膜与银纳米立方体复合结构由于存在局域表面等离子体和传播表面等离子体的共振耦合,使得光栅脊与银纳米立方体下顶点接触处热点的电场增强因子高达1.53×106.该复合结构产生的超高电场增强因子,有望应用于表面增强拉曼散射的研究. 相似文献
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茶叶表面增强拉曼光谱的初步研究 总被引:2,自引:0,他引:2
以铁观音为例,测试其表面增强拉曼(SERS)光谱,并从增强能力、背景噪声、光谱重复性和信噪比等方面,研究探讨铁观音茶叶SERS光谱测试时活性基底选择;不同吸附时间对光谱测试的影响。结果表明:以柠檬酸三钠还原硝酸银制得的银溶胶为活性基底的增强效果更好,吸附时间对于铁观音茶叶SERS光谱的测试没有直观的影响。SERS光谱的茶叶研究方法有可能为茶叶的判别和质量鉴定提供一种新的方法。 相似文献
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提出一种新型的荧光及表面增强拉曼散射(SERS)双模式光学纳米探针。首先,通过再沉淀-包覆法合成二氧化硅包覆香豆素6的纳米颗粒,再在二氧化硅表面静电吸附多聚赖氨酸分子形成包覆层,随后通过原位还原的方法在多聚赖氨酸壳层复合银纳米颗粒,最后在银纳米颗粒表面吸附拉曼分子即形成双模式纳米探针。该探针通过二氧化硅包覆的荧光分子产生荧光信号,以多聚赖氨酸表面的银纳米颗粒作为SERS增强基底,利用拉曼分子获得SERS信号,实现了荧光及SERS双模式成像。荧光与表面增强拉曼散射相结合的双模式分析技术可同时发挥二者的优点,提高成像的分辨率和灵敏度,在生物医学领域具有重要的应用价值。 相似文献
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Renming Liu Xingfa Zi Yipu Kang Minzhen Si Yanchun Wu 《Journal of Raman spectroscopy : JRS》2011,42(2):137-144
Polyvinyl alcohol (PVA)‐protected silver nanoarchitecture (PVA Ag nanofilm) on the surface of the glass substrate was prepared by using electrostatic self‐assembly at a proper voltage. The two‐dimensional morphology of the PVA Ag nanofilm has been examined by scanning electron microscopy (SEM). The surface‐enhanced Raman scattering (SERS) spectra of human serum (HS) on PVA Ag nanofilms were recorded. The results show that the Raman scattering of HS can be enhanced efficiently based on these PVA Ag nanofilms. However, it also can be seen that the effect of sodium citrate (SC) acting as anticoagulant on the SERS spectrum of HS is unnegligible, which has not been discussed adequately in the previous reports. To discuss the effect of SC on the SERS spectrum of HS, we have studied the normal Raman spectra of solid SC and the SERS spectra of 1.0 × 10−3 mol/l aqueous solution of SC adsorbed on the PVA–Ag nanofilms. Meanwhile, Raman wavenumbers of the SC molecule were calculated by using the method of DFT‐B3LYP/6‐31G*, and the dominant assignations of the calculated wavenumbers were performed. It was found that the density functional theory (DFT) calculation of SC Raman spectrum matches well with the experimental results. With the perfect reproducibility and high SERS activity, this method will be useful in the development of HS detection methods. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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S. N. Terekhov L. L. Gladkov O. L. Gladkova M. V. Parkhats I. A. Khodasevich A. Yu. Panarin P. Y. Turpin 《Optics and Spectroscopy》2009,106(6):813-820
The resonance and surface enhanced Raman scattering (SERS) spectra of chlorin e 6 trisodium salt in aqueous solutions, solid films, and adsorbed on the silver-coated surface of porous silicon are presented. Using the quantum-mechanical density functional method, the geometric structure and vibrational frequencies of the chlorin e 6 molecule are calculated and the Raman spectrum of this molecule is interpreted for the first time. The geometry of sorption of chlorin e 6 on the surface of a nanostructured silver film is considered based on a comparative analysis of the resonance Raman and SERS Raman spectra in the approximation of a short-range mechanism of Raman scattering enhancement. 相似文献
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Surface‐enhanced Raman scattering and density functional theory studies of bis(4‐aminophenyl)sulfone
Guillermo Diaz‐Fleming Freddy Clis Carlos Fredes Marcelo Campos‐Vallette Alvaro E. Aliaga Rainer Koch 《Journal of Raman spectroscopy : JRS》2010,41(2):160-166
Raman and surface‐enhanced Raman scattering (SERS) spectra of dapsone by using colloidal silver nanoparticles have been recorded. Density functional theory was used for the optimization of ground state geometries and simulation of the vibrational spectrum of this molecule. The SERS spectrum with a large silver cluster as a model metallic surface was simulated for the first time. Taking into account the experimental and calculated Raman as well as the SERS normal modes and the corresponding assignments, along with the modeling of the free dapsone and the one in the presence of the colloidal silver nanoparticles, the importance of the sulfone group on the SERS effect in dapsone was inferred. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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AAO模板法制备CdS纳米微粒的SERS光谱研究 总被引:2,自引:1,他引:2
在自制的孔径约15nm多孔氧化铝模板上沉积银纳米粒子,然后用电化学方法在此衬底上沉积CdS纳米微粒。研究了CdS纳米阵列在457.5nm波长激光激发下的表面增强拉曼散射(SERS)性质。实验结果显示CdS的SERS信号有三个振动模式,分别对应1LO、2LO和3LO纵光学声子模,它们的强度随着作为SERS衬底的银纳米粒子高度的增加而增强,当银纳米粒子的长/径比(长度与直径的比值)达到4时,这种增强趋近饱和。最后对CdS纳米微粒光学声子模的增强机理进行了分析和讨论。 相似文献
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Raman, surface-enhanced Raman scattering, and shell isolated nanoparticles-enhanced Raman scattering techniques were used to study the indigo–nanoparticle interaction nature. Silver nanoparticles were employed with and without a silicon dioxide spacer inert layer. The SERS spectral profile, obtained using silver nanoparticles, is different from the Raman one, which led to the proposition that the indigo–silver interaction is in the range of intermolecular interactions. SERS spectral reproducibility suggests identical organization and orientation of the analyte on the metal surface. The shell isolated nanoparticles enhanced Raman scattering spectrum of indigo, obtained by using silicon dioxide coated silver nanoparticles resulted similar to its Raman spectrum. This result indicates that the indigo structure is chemically unmodified by the silicon dioxide-coated silver surface. From the shell-isolated nanoparticles-enhanced Raman scattering experiments, the electromagnetic mechanism is proposed as the reason for the spectral enhancement. Theoretical calculations allow one to infer both the indigo–silver surface interaction nature and the orientation of indigo on the surface. 相似文献
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核酸中通过多重氢键发生的互补碱基之间的分子识别是自发产生的并具有高度的选择性,是遗传信息存储和复制的高效机制之一。近年来由含核酸碱基的类脂形成的表面单层体系,模拟DNA复制过程中的互补碱基通过多重氢键而发生的分子识别过程已引起广泛注意[1-20],已... 相似文献
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Compacted powders of commercially available nano‐ and microparticles of silver were used to successfully induce the surface‐enhanced Raman scattering (SERS) effect in spruce milled‐wood lignin (MWL). For the two silver particle sizes used in this investigation, the spectra were mostly similar. Some general characteristics of the lignin SERS spectrum are described. The SERS technique was found to be sensitive for detecting lignin. Significant spectral changes were present between the SERS and normal Raman spectra of MWL. The SERS spectrum was assigned on the basis of literature‐reported vibrational assignments of lignin and its models. Based on significant changes in Raman features, we propose that the lignin is strongly adsorbed on silver. To determine whether SERS of lignin can be obtained directly from wood without its isolation, Wiley‐milled spruce wood (WMW) adsorbed on silver was studied. The results indicated that not only the surface‐enhancement effect was successfully induced in the WMW, but that its spectrum was similar to MWL SERS. Moreover, for WMW, no signals from the carbohydrate components were observed, and therefore, lignin was detected selectively. This nano‐ and microparticle‐based molecularly specific method is expected to make a significant contribution in identifying and investigating lignin in various lignin‐containing materials. Published in 2009 by John Wiley & Sons, Ltd. 相似文献