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Chun Kwan Tsang Shiwei Shu Fengxia Liang Jie Zhang Lingxia Zheng Yang Yang Li 《Journal of Raman spectroscopy : JRS》2013,44(1):29-34
Nanovolcano arrays were fabricated by electrodepositing Ni/Cu alloys into a monolayer of self‐assembled nanospheres and then electrochemically etching the deposited alloy film. The fabricated nanovolcano arrays feature highly ordered hexagonally arranged concave nanobowls decorated with triangular nanopores at their interstices. After coated with Ag, the nanovolcano arrays serve as high‐performance substrates for surface enhancement Raman spectroscopy (SERS) measurements. The experimental study shows that the structural features of the nanovolcano arrays, including concave nanobowls, nanopores, and their long‐range orders, all contribute to the observed strong SERS enhancement in a synergetic manner, which is further confirmed by the simulation results obtained using the finite‐difference time‐domain method. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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We present a method of incorporation of gold nanoparticles in SDS (sodium dodecyl sulfate) bubbles with a low polydispersity index (monodispersed nanoparticles). Both the bubbles and nanoparticles maintained their structural and morphologic properties after functionalization. The bubbles present a radio of 0.38 mm with a standard deviation of±0.018 mm. The gold nanoparticles were obtained with sucrose as the catalytic agent and ascorbic acid as the reducing agent. The nanoparticles display several geometric morphologies as well as sizes inferior to 50 nm, as observed in the images obtained with Transmission Electron Microscopy (TEM). The optical properties were studied by optical absorption spectroscopy. The absorption band linked to the surface plasmon resonance (SPR) is located at 550 nm before and after the functionalization of the bubbles. Moreover, microscopic bubbles with a diameter smaller than 1 µm with the ability to stabilize nanoparticles in their surface were found in isolated regions of the sample. Additionally, the Surface Enhancement Raman Spectroscopy (SERS) properties of the colloid were analyzed with common drugs. 相似文献
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在后摩尔时代,突破原有技术极限,进行原子尺度的精准构筑,是当前的重大科学问题.DNA作为具有原子级精准度的生物大分子,能够进行程序性的分子识别,构筑原子数量与位置均严格确定的自组装结构,因此是进行原子制造的理想平台.本文提出基于DNA自组装折纸结构的精准定位能力,构筑铁原子阵列图案,并应用于对信息的加密.实验结果表明,采用类似“信息预置”的方法,铁原子成功实现在DNA折纸不同位置的高效定位,此方法还极大降低了实验工作量,非常有利于多种不同阵列图案的平行制备.利用所构建的铁原子阵列,本文发展了原子阵列DNA折纸加密技术,将密文编码为二进制并用类似盲文斑点的形式在DNA折纸上以特定图案表示,通过单分子成像手段对密文信息进行了读取,而密钥长度可高达700位以上.作为示例,成功地对普通文本及唐诗《登鹳雀楼》进行了加密,证明了此策略的通用性和实用性. 相似文献
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Zenidaka Akira Tanaka Yuto Miyanishi Tomoya Terakawa Mitsuhiro Obara Minoru 《Applied Physics A: Materials Science & Processing》2011,103(1):225-231
We describe the optical power enhancement on the surface of the 2D (two-dimensional) periodic arrays of convex and concave
gold nanostructures for comparing the characteristics of the nanostructures for surface-enhanced Raman spectroscopy (SERS)
templates. The optical power enhancement is due to the surface plasmon polaritons, which is calculated by the Finite-Difference
Time-Domain (FDTD) method at commercially-available 532 nm pump light. A periodic array of closely-packed gold particles is
defined as convex nanostructure, while a periodic array of hemispherical holes, or voids, on gold substrate is defined as
concave nanostructure. The peak power enhancement factor, the average power enhancement factor and the activity rate of each
structure were compared. The convex nanostructures show a strong enhancement factor in localized hotspots, while the concave
nanostructures show not only the peak power enhancement factor comparable to that of convex nanostructures, but also higher
spatially-averaged power enhancement factors and activity rates than those observed on the convex nanostructures, meaning
that the highly enhanced near-field zone distributes densely on the substrate. We also revealed the dependence of the void
diameter on the inter-void distance for the power enhancement in the concave nanostructures system, providing a guideline
for the fabrication of the efficient SERS template, which shows a strong power enhancement factor with a high area density. 相似文献
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Jiyuan Yang Yu Lin Yongming Meng Yibing Lin 《Applied Physics A: Materials Science & Processing》2014,114(4):1195-1199
Dye-sensitized solar cells (DSSCs) based on a novel composite photoanode of TiO2 nanoparticles coating on electrodeposited ZnO nanotube arrays are fabricated and characterized. An efficiency of 3.94 % is achieved for the composite cell, increasing 86.7 % than 2.11 % of the ZnO nanotubes cell. The short-circuit current (J sc) and open-circuit voltage (V oc) are also enhancing 52.9 % and 25.3 %, respectively. The improvements are because of the high surface area of TiO2 nanoparticles, as well as fast electron transport and light scattering effect of ZnO nanotubes. 相似文献
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A.-S. Grimault A. Vial M. Lamy de la Chapelle 《Applied physics. B, Lasers and optics》2006,84(1-2):111-115
We study the localized surface plasmon resonance (LSPR) and the surface-enhanced Raman scattering (SERS) of arrays of gold
cylindrical and ellipsoidal nanoparticles with different diameters or major axes. The LSPR and SERS gains are calculated with
the three dimensional Finite-Difference Time-Domain method using the Drude–Lorentz dispersion model. We find that the maximum
of the extinction spectrum and the average SERS gain of each investigated nanostructures are shifted whatever their size and
their shape.
PACS 42.25.Fx; 71.45.Gm; 78.30.-j 相似文献
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A. Renier T. Mangeat H. Benalia C. Elie-Caille C. Pieralli B. Wacogne 《Laser Physics》2010,20(3):591-595
The work described here concerns the fabrication of cost-effective biosensors that permit to amplify a fluorescence signal
without a complex nano-structuration of the surface. The idea is to put to profit the natural pseudo nano-structuring that
is observed when depositing metallic layers by various micro-fabrication techniques. This new architecture consists of a glass
substrate. A gold film is deposited on the top of it and a silica layer onto the gold. A dye (Cy5) is then absorbed onto the
surface and the fluorescence intensity is measured. This intensity depends on the distance between the dye and the metal.
It also depends on the properties of the metallic film. The goal of the work is to determine which gold deposition method
leads to the highest fluorescence amplification and which silica thickness is required to achieve this amplification. 相似文献
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We demonstrate that ordered arrays of metal clusters of a few nanometers in size can be fabricated by self-assembly on a range of oxide nanotemplates. Two systems were chosen, FeO/Pt(1 1 1) and Fe3O4, having in common a reconstructed close-packed oxygen surface layer. Deposition of various metal films results in the formation of nanosized clusters arranged according to the surface long-range order. Employing ab-initio calculations we discuss the observed mechanism of site-selective nucleation of the metal nanoclusters. Finally, we discuss the existence of a wide family oxide templates that can be used for self-assembled growth of nanoclusters governed by the same rules. 相似文献
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Ganesh K. Kannarpady Rajesh Sharma Steve Trigwell Alexandru S. Biris 《Applied Surface Science》2010,256(6):1679-9943
A novel technique to modify a metallic surface for anti-icing applications is presented. An oblique angle deposition (OAD) technique has been used to fabricate metallic nanorods of Aluminum and Tungsten on a glass substrate. A conformal coating of a silane has been applied using a molecular vapor deposition technique. The resulting surface has shown a static contact angle of 134° with the water droplet. SEM, AFM and XPS have been used to study the surface modification. This is a highly promising approach for anti-icing applications due to its scalability at a very low cost. 相似文献
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Wei Song Xiaoxia Han Lei Chen Youming Yang Bin Tang Wei Ji Weidong Ruan Weiqing Xu Bing Zhao Yukihiro Ozaki 《Journal of Raman spectroscopy : JRS》2010,41(9):907-913
A controllable heterostructure consisting of ZnO nanorod arrays with attached Ag nanoparticles at only one end has been synthesized via a facile and convenient galvanic reduction method. Scanning electron microscopic images of these nanostructures showed good selectivity of Ag deposition on the tip of ZnO nanorod arrays. The formation of these regular Ag ZnO heterogeneous nanorod arrays can be explained by a localization of the electrons at the ends of the ZnO nanorods after the electron transfer step. By tuning the reaction time and the concentration of silver nitrate, the density of Ag nanoparticles on the tip of ZnO nanorods can be well controlled. Owing to the introduction of Ag nanoparticles with different densities, the resulting Ag ZnO heterogeneous nanorod arrays have been proved to be a versatile substrate for surface‐enhanced Raman scattering not only for common organic molecules but also for label‐free protein detection. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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A. Bello M. Fabiane D. Dodoo-Arhin K.I. Ozoemena N. Manyala 《Journal of Physics and Chemistry of Solids》2014
Silver metal nanoparticles were decorated by electron beam evaporation on graphene foam (GF) grown by chemical vapour deposition. X-ray diffraction, Raman spectroscopy, scanning and transmission electron microscopy, and atomic force microscopy were used to investigate the structure and morphology of the graphene foam/silver nanoparticles (GF/Ag). Both samples were tested as electrodes for supercapacitors. The GF/Ag exhibited a significantly higher capacitive performance, including a specific capacitance value of (~110 Fg−1) and excellent cyclability in a three-electrode electrochemical cell. These results demonstrate that graphene foam could be an excellent platform for metal particles for investigating improved electrochemical performance. 相似文献
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由于微流控芯片具有优异的集成性和灵活的可操作性,基于芯片上的检测方法被大量开发,发展十分迅速。其中,表面增强拉曼光谱(SERS)凭借其超高的灵敏度、独一无二的指纹谱和窄峰宽等特点成为一种广泛采用的检测手段。SERS微流控芯片集SERS检测技术与微流控芯片的优势于一体,一方面为SERS检测方法的重复性和可靠性提供了一个高效平台,另一方面推动了微流控芯片的功能拓展,在生物分子探测、细胞捕获乃至组织模拟等领域具有广阔的应用前景。本文在简要介绍SERS的原理及其生物传感应用的基础上,重点概述了SERS微流控芯片的构建及其在生物传感及检测中的应用,最后探讨了该研究方向存在的问题及发展方向。 相似文献
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Zachary A. Sechrist Ronald J. Tonucci Lee R. Cambrea 《Applied physics. B, Lasers and optics》2013,112(1):133-142
A finite element solver is used to design a metamaterial structure with large and stable Raman scattering enhancement. The metamaterial consists of an array of tapered nanowells etched into a metal/dielectric multilayer stack. The plasmonic activity as a function of the number of layers and sidewall angle of the nanowell is investigated. As the nanowell side wall angle is increased, the tops of the nanowells are drawn closer together, greatly increasing the local electric field intensity. The taper is designed such that the patterned layers at the bottom of the nanowell would have a negative refractive index if isolated from the stack, and patterned layers at the top of the stack would have a positive refractive index if isolated from the stack. Simulations predict that coupled layers at the bottom of the tapered nanowell, exhibiting a negative refractive index, experience a blue shift in local resonant frequency as the well diameter is increased or the period is decreased. The upper layers, with positive refractive index, exhibit a red shift as the well diameter is increased or the period is decreased. These opposing responses stabilize the resonant frequency with respect to variations in diameter and periodicity commonly encountered with nanofabrication techniques. 相似文献
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A series of porous silicon samples prepared at different etching parameters, namely etchant composition, etching time and current density, was investigated as substrates for surface-enhanced Raman scattering (SERS). Silver nanostructures were deposited on porous silicon by immersion plating method and Rhodamine 6G was used as analyte. The relation between the etching parameters, morphology of porous silicon surface and its SERS efficiency after silver deposition is examined. We show that a high HF content in the etchant allows the formation of a film with close-packed silver nanocrystals, which possess strong surface enhancement properties. 相似文献