共查询到20条相似文献，搜索用时 15 毫秒
1.
Wei Xiong Qidong Zhao Xinyong Li Lianzhou Wang 《Particle & Particle Systems Characterization》2016,33(9):602-609
A new type of multifunctional plasmonic nanoparticles, cobalt‐doped Fe2O3@polydopamine‐Au (Co‐Fe2O3@PDA‐Au), is fabricated via coating PDA through self‐polymerization onto Co‐Fe2O3 and further loading gold nanoparticles by in situ reduction onto the surface of PDA shell. Benefiting from the universal adhesive ability of PDA and negative zeta potetntial of the composite, the Co‐Fe2O3@PDA‐Au shows strong adsorptivity for cationic dyes. The presence of gold nanoparticle with the diameter of 15 nm in the Co‐Fe2O3@PDA‐Au system promotes surface‐enhanced Raman scattering (SERS) activity with an impressive detection limit of 1 × 10?6 m . Thanks to the synergistic effect of the light harvesting of PDA, the surface plasmon resonance of Au, and the electron conductibility of PDA and Au, the Co‐Fe2O3@PDA‐Au exhibits an enhanced photocatalytic activity comparing with unmodified Co‐Fe2O3. All the above‐mentioned functions enable Co‐Fe2O3@PDA‐Au to be a multifunctional material system for various applications toward environmental pollutants. 相似文献
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《Journal of Raman spectroscopy : JRS》2018,49(8):1395-1401
The coupling reaction of 4‐nitrothiophenol to 4,4′‐dimercaptoazobenzene was investigated by surface enhancement Raman scattering method. The reaction was found to be controlled by the compatibility of organic alkalis and silver nanoparticles. The effect of hot electron–hole pairs on the reaction was evaluated. Furthermore, the mechanism of organic alkalis affecting hot electron–hole pairs to achieve regulation of the coupling reaction of 4‐nitrothiophenol to 4,4′‐dimercaptoazobenzene was studied. A comprehensive analysis of the different surface enhancement Raman scattering signals collected was conducted. The forward‐looking view of capturing holes through the hydrolysis of organic alkalis to ensure the integrity of the substrate was also presented. 相似文献
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Chia-Yu Chang Yun-Ching Hsieh Yung-Yi Huang Yun-Jie Wang Yu-Mei Chen Yu-Bin Huang Wei-Hsiu Hung Ying-Huang Lai 《Journal of Raman spectroscopy : JRS》2019,50(6):818-825
We fabricate crystalline dendritic gold (Au-D) via a simple electrochemical method and characterize it using several techniques. Chemical modification by self-assembled thiol molecules on the Au-D is used to adjust the chemical environment of the substrate surface and to improve surface-enhanced Raman scattering (SERS) performance. First, the Au-D modified with different length chains of n-alkyl thiols cause an enhancement of SERS, which follows a relationship of normalized intensity, , versus (1 + ) with a slope of −10 according to the electromagnetic mechanism. Subsequently, phenyl thiols with various end-functional groups are attached to study the effect of chemical modification on SERS enhancement. The results indicate that the 4-methylthiophenol- and thiophenol-modified substrates do not exhibit significant SERS enhancement, resulting in intensity being dependent on distance. It is worth noting that the 4-mercaptophenol- and 4-aminothiophenol-modified surfaces have an effective electric field effect and strong interaction with polarity probe molecules, and they produce a more intense signal than do bare Au-D particles. 相似文献
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AbstractSurface-enhanced Raman scattering (SERS) has attracted great interest due to its remarkable enhancement, excellent sensitivity, and the “fingerprinting” ability to produce distinct spectra for detecting various molecules. Noble metal nanomaterials have usually been employed as SERS-active substrates because of their strong SERS enhancement originated from their unique surface plasmon resonance (SPR) properties. Because the SPR property depends on metal material's size, shape, morphology, arrangement, and dielectric environment around metal nanostructures, the key to wider applications of SERS technique is to develop plasmon-resonant structures with novel geometries to enhance Raman signals and to control the periodic ordering of these structures over a large area to obtain reproducible Raman enhancement. This review presents a general view on the theory background of SERS effect and several basic concepts and focuses on recent progress in engineering metallic nanostructures with various morphologies using versatile methods for improving SERS properties. Their potential applications in the field of chemical detection and biological sensing are overviewed. 相似文献
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Plasmonic nanostructures can achieve subdiffraction‐limit light confinement with enhanced electric fields. By taking advantage of the light‐confinement effect, various plasmonic photodetectors that combine low‐dimensional (LD) semiconductor structures and plasmonic materials have recently demonstrated excellent plasmon‐enhanced device performance and attracted significant research interest. In this review, the state‐of‐the‐art progress in the development of various LD photodetectors with different plasmonic structures is briefly surveyed, in order to provide a clear picture of related fabrication methods, leading to maximized plasmonic enhancement. The fundamentals of localized surface‐plasmon resonance and plasmonic hot electrons are first introduced, followed by a summary of several prototypical LD photodetectors enhanced by metal nanoparticles (NPs), including noble‐metal NPs, poor‐metal NPs, and some plasmonic doped‐semiconductor NPs. The recent achievement of the newly developed LD photodetectors propelled by plasmonic hot carriers is also highlighted. Finally, some challenges and issues that need to be resolved in this field are proposed. 相似文献
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Yi‐Chieh Chen Robert J. Young Julie V. Macpherson Neil R. Wilson 《Journal of Raman spectroscopy : JRS》2011,42(6):1255-1262
We report on investigations upon a surface‐enhanced Raman scattering (SERS) substrate produced from a two‐dimensional single‐walled carbon nanotube (SWNT) network decorated with Ag nanoparticles. Using the strong and unique Raman spectrum of SWNTs as a reference, the SWNT/Ag nanostructure can be considered to provide two regions: one with an ultrasensitive SERS response for single‐molecule SERS (SMSERS) study; and another with uniform SERS enhancement over an area of several square millimeters for general SERS measurements. We report the appearance of an anomalous Raman feature at around 2180 cm−1 in the high‐sensitivity region which exhibits the characteristics of SMSERS. The SERS performance of the uniform area was characterized using pyridine vapor adsorbed onto the substrate. The presence of the SWNT/Ag nanostructure enhanced the Raman intensity by over seven orders of magnitude, a factor comparable to or exceeding that obtained on SERS substrates reported by other groups. The results indicate great potential to produce highly sensitive, uniform SERS substrates via further fine‐tuning of the nanostructure. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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《中国物理 B》2021,30(7):77301-077301
Localized surface plasmon has been extensively studied and used for the photocatalysis of various chemical reactions.However, the different contributions between plasmon resonance and interband transition in photocatalysis has not been well understood. Here, we study the photothermal and hot electrons effects for crystal transformation by combining controlled experiments with numerical simulations. By photo-excitation of Na YF4:Eu~(3+)@Au composite structure, it is found that the plasmonic catalysis is much superior to that of interband transition in the experiments, owing to the hot electrons generated by plasmon decay more energetic to facilitate the reaction. We emphasize that the energy level of hot electrons plays an essential role for improving the photocatalytic activity. The results provide guidelines for improving the efficiency of plasmonic catalysis in future experimental design. 相似文献
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《Advanced Optical Materials》2018,6(13)
Owing to its narrow indirect bandgap, bulk bismuth telluride (Bi2Te3) exhibits exceptionally low room‐temperature photoluminescence (PL). Consequently, it remains challenging to achieve promising optical and optoelectronic performance from Bi2Te3. Moreover, due to the lack of plasmonic materials and available modulation methods, it is challenging to effectively control the surface plasmon resonance intensities in the visible region. Herein, thickness‐dependent photoluminescence studies unveil ultrahigh (282‐fold) room‐temperature photoluminescence (visible) from 20 quintuple layer Bi2Te3 nanosheets (NSs) compared to 200 quintuple layer NSs, attributable to a significant bandgap opening. Intriguingly, considerable photoluminescence quenching is observed beyond the thickness of 20 quintuple layer Bi2Te3. The PL emission is further optimized with reference to the number of quintuple layers, and the mechanism possibly responsible for such PL behavior is elucidated. Moreover, the thickness modulation is put forward as an effective strategy to control visible surface plasmon resonance energy modes and their intensities. Bi2Te3 nanosheets with large area and high crystallinity are fabricated on various silicon substrates by a facile hot‐pressing strategy, which facilitates investigation of intrinsic properties of 2D Bi2Te3. It is believed that these findings hold paramount importance in understanding the optical response of Bi2Te3 toward nanoscale variations and help build next‐generation transparent and flexible optoelectronic/plasmonic devices. 相似文献
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We derive analytical expressions for the surface- and orientation-averaged surface enhanced Raman scattering factor (SERS EF) for small plasmonic spheroids. These expressions are derived taking into account the Stokes shift and are shown to result in very different EFs to those in the |E|4-approximation for experimentally relevant parameters. The optical properties of spheroids are treated in terms of the common and improved electrostatic approximations (EA and IEA). The latter is newly introduced here and includes radiative damping, depolarization effects, and interactions with higher order multipoles, thus giving perfect agreement with exact T-matrix calculations of far-field cross sections and near-field SERS EFs over a much wider range of sizes. These accurate analytical expressions will be particularly relevant to SERS experiments in colloidal solutions where surface averaging (because of random molecular adsorption) and particle orientation averaging must both be taken into account. Comparison with recent experimental data and simulations for cigar-like particles show that the spheroid model tends to overestimate the SERS EF because of the higher curvature at the tips. Possible ways to generalize the analytic solution to other axially symmetrical particles are discussed. 相似文献
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Trong Duc Tran Thi Hue Nguyen The Binh Nguyen 《Journal of Raman spectroscopy : JRS》2022,53(6):1039-1047
We propose and develop a simple and cost-effective method to fabricate surface enhanced Raman scattering (SERS) substrates for the trace detection of antibiotics. A nanostructured silicon (Si) surface is prepared by the pulsed laser ablation (PLA) of a Si wafer in distilled water. Silver nanoparticles (AgNPs) synthesized via PLA in distilled water are deposited on the ablated Si surface to form a SERS substrate (AgNP/aSi). Malachite green (MG) is used as a probe analyte to examine the SERS activity of the AgNP/aSi substrate. The AgNP/aSi substrate can yield an SERS spectrum of MG with high resolution at a minimum concentration of 0.01 ppm. Using the AgNP/aSi substrate, we investigate its capacity for detecting tetracycline (TC) residue in shrimp. The Raman peak intensities at 1320 cm−1 for TC concentrations from 10 to 0.1 ppm show a linear relationship with the corresponding logarithmic concentrations. Our simple and efficient method can be used for the trace detection of MG, TC, and other antibiotics in various applications via SERS. 相似文献
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以经过硅烷化后玻璃片为基底,之后吸附金纳米种子,采用柠檬酸钠为还原剂,在荧光灯照射条件下还原硝酸银,制备出基底表面具有银纳米粒子聚集结构的材料。采用透射电镜、扫描电镜和紫外可见分光光度计对产物的形貌和性质进行了表征,并考察银纳米粒子的形貌对其薄膜基底SERS活性的影响。结果表明：随着光照时间增加至16 h,金种子长大为平均粒径110 nm的不规则状多晶银纳米粒子,且出现双层粒子堆积。基底上纳米粒子的吸收光谱上出现了由银粒子的表面等离子体激元偶极子耦合引发的强烈吸收峰：随着光照时间的变化,耦合峰在600～813 nm波段内移动。光照时间为12 h后得到的SERS活性基底具有最强的SERS信号。 相似文献
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以经过硅烷化后玻璃片为基底,之后吸附金纳米种子,采用柠檬酸钠为还原剂,在荧光灯照射条件下还原硝酸银,制备出基底表面具有银纳米粒子聚集结构的材料。采用透射电镜、扫描电镜和紫外可见分光光度计对产物的形貌和性质进行了表征,并考察银纳米粒子的形貌对其薄膜基底SERS活性的影响。结果表明：随着光照时间增加至16 h,金种子长大为平均粒径110 nm的不规则状多晶银纳米粒子,且出现双层粒子堆积。基底上纳米粒子的吸收光谱上出现了由银粒子的表面等离子体激元偶极子耦合引发的强烈吸收峰：随着光照时间的变化,耦合峰在600～813 nm波段内移动。光照时间为12 h后得到的SERS活性基底具有最强的SERS信号。 相似文献
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Terahertz radiation from interaction between an electron beam and a planar surface plasmon structure 
下载免费PDF全文
下载免费PDF全文 The possibility of an electron beam exciting surface plasmons in
conducting metal is discussed in this paper. A planar
perfect-structure with subwavelength holes is proposed. The
phenomenon that mimicking
surface plasmon waves can be excited and amplified by an electron
beam is proved theoretically and numerically. The mechanism of transmission through a subwavelength hole
array is exploited to enhance the interaction between the electron beam
and the mimicking surface plasmons. 相似文献
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Emilia Giorgetti Paolo Marsili Francesco Giammanco Silvana Trigari Cristina Gellini Maurizio Muniz‐Miranda 《Journal of Raman spectroscopy : JRS》2015,46(5):462-469
We studied the surface properties and reactivity of silver nanoparticles obtained by picosecond or nanosecond pulsed laser ablation in water and with 1064‐nm wavelength. Ultraviolet–visible spectroscopy results and subsequent modelling by Mie theory indicated the presence of an oxide layer on the nanoparticle surface, which favours the colloidal stability, but reduces the interaction with the environment. The oxide layer is also responsible for the reduced surface enhanced Raman spectroscopy (SERS) activity of these colloids with respect to those obtained by chemical reduction. However, SERS activation can be efficiently obtained by addition of chloride ions to the colloids, leading to SERS enhancement factors that are comparable with those of the chemically prepared counterparts. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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Based on the finite difference time domain method,we investigated theoretically the optical properties and the plasmonic interactions between a gold film perforated with periodic sub-wavelength holes and a thin gold film.We showed that the plasmon resonant energies and intensities depend strongly on the thicknesses of the two films and the lattice constant.Based on the distributions of normal electric field component E z,tangential electric field component E y and total energy,we showed that the optical transmission is due to the collaboration of the localized waveguide resonance,the surface plasmon resonance and the coupling of the flat-surface plasmon of the two layers. 相似文献
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Etienne Pertreux Anna Lombardi Ileana Florea Miguel Spuch‐Calvar Sergio Gmez‐Graa Dris Ihiawakrim Charles Hirlimann Ovidiu Ersen Jrme Majimel Mona Trguer‐Delapierre Mike Hettich Paolo Maioli Aurlien Crut Fabrice Valle Natalia Del Fatti 《Advanced Optical Materials》2016,4(4):567-577
Modification of the plasmonic response of a metal nano‐object due to interaction with a substrate is experimentally investigated measuring the quantitative optical extinction spectra of individual nano‐objects with various elongated shapes (bipyramids and rods) deposited on a dielectric (silica) or absorbing (carbon) membrane. Apart from the expected dependence of the nanoparticle surface plasmon resonance (SPR) frequency on the nature of the substrate, large substrate and particle shape dependent modifications of its SPR width are demonstrated. These dependencies are ascribed to strong localization of the electromagnetic field associated with the longitudinal SPR of an elongated nano‐object around its tips, leading to different interaction with the substrate depending on the particle shape and 3D orientation relative to the substrate. Both parameters have been precisely determined by electron tomography, permitting excellent reproduction of the experimental data. Experiments performed on silver‐encapsulated bipyramids, whose shape evolves from a pyramidal one towards a cylindrical one, further confirm this effect. 相似文献