Academic literature on the topic 'Surface plasmon resonance. Raman effect, Surface enhanced. Nanoparticles'
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Journal articles on the topic "Surface plasmon resonance. Raman effect, Surface enhanced. Nanoparticles"
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Fleger, Y., and M. Rosenbluh. "Surface Plasmons and Surface Enhanced Raman Spectra of Aggregated and Alloyed Gold-Silver Nanoparticles." Research Letters in Optics 2009 (2009): 1–5. http://dx.doi.org/10.1155/2009/475941.
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Effects of size, morphology, and composition of gold and silver nanoparticles on surface plasmon resonance (SPR) and surface enhanced Raman spectroscopy (SERS) are studied with the purpose of optimizing SERS substrates. Various gold and silver films made by evaporation and subsequent annealing give different morphologies and compositions of nanoparticles and thus different position of the SPR peak. SERS measurements of 4-mercaptobenzoic acid obtained from these films reveal that the proximity of the SPR peak to the exciting laser wavelength is not the only factor leading to the highest Raman enhancement. Silver nanoparticles evaporated on top of larger gold nanoparticles show higher SERS than gold-silver alloyed nanoparticles, in spite of the fact that the SPR peak of alloyed nanoparticles is narrower and closer to the excitation wavelength. The highest Raman enhancement was obtained for substrates with a two-peak particle size distribution for excitation wavelengths close to the SPR.
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Zhang, Jie, Yu Lin Chen, Tuo Fan, and Yong Zhu. "Large Area Au Decorated Multi-Walled CNTs Film for Surface Enhanced Raman Scattering." Key Engineering Materials 562-565 (July 2013): 826–31. http://dx.doi.org/10.4028/www.scientific.net/kem.562-565.826.
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We reported on a study upon a Surface-enhanced Raman Scattering (SERS) substrate produced from a large area multi-walled carbon nanotube (MWCNT) films decorated with Au nanoparticles. The morphology and spectrum of the MWCNTs/Au composite structure was characterized with scanning electron microscopy and spectrophotometer. The SERS signals of Rhodamine 6G (R6G) absorbed on the substrate were improved, which could contribute to the enlarged surface area for adsorption of molecules and Localized Plasmon Resonance Effect. The results indicated that it is potential to produce sensitive SERS substrates via further fine-tuning of size, shape of the nanostructure.
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Kassim, Syara, Nor Abidah Mukhtar, and Rabiatul Addawiyah Azwa Tahrin. "Synthesis and Characterization of Plasmon-Enhanced SERS Substrate Based on Au-Ag Alloy-Coated, Large-Area Photonic (Methyl Methacrylate+Styrene) Co-Polymer." Materials Science Forum 982 (March 2020): 14–19. http://dx.doi.org/10.4028/www.scientific.net/msf.982.14.
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Enhancement of surface-enhanced Raman scattering (SERS) by metal nanoparticles has attracted considerable interest on account of their widespread popularity of SERS-based measurements and devices ranging from life science until materials science. Current study focuses on noble metal SERS substrates with attempting to achieve high and enhanced effect by describe a plasmon-enhanced SERS substrate based on gold-silver, alloy-coated co-polymer (methyl methacrylate-styrene) colloidal sphere. Copolymer was synthesised via surfactant-free emulsion polymerization and was successfully produced a homogeneous colloidal spheres. The homogenous spheres of copolymer would promote periodic array upon fabrication and more, introducing the copolymer medium had improved the thermal degradation of the material compare to single polymer. Gold-silver alloy nanospheres was synthesised via one pot reduction method using citrate stabilizer. The nanoalloy obtained are well within the nanoscale domain (<100 nm) supported by the maximum surface plasmon resonance peak at 436 nm using UV-Visible spectroscopy. The perfect combination of our proposed alloy nanoparticles and copolymer present an ability to enhance Raman scattering by higher than 90 %. The region of high electron density of the substrate is expected to develop a new opportunities for SERS detections in wide analytical area.
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Liu, Runcheng, Zhipeng Zha, Muhammad Shafi, et al. "Bulk plasmon polariton in hyperbolic metamaterials excited by multilayer nanoparticles for surface-enhanced Raman scattering (SERS) sensing." Nanophotonics 10, no. 11 (2021): 2949–58. http://dx.doi.org/10.1515/nanoph-2021-0301.
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Abstract The capability to support large wave vector bulk plasmon polariton (BPP) waves enables the application of hyperbolic metamaterials (HMMs) in sensing. However, there is a challenge arising from the excitation of BPP, and the highly confined polarization waves are unable to meet the requirements of practical application. In this study, an HMM/bilayer silver nanoparticles (Ag NPs) platform is proposed that allows the excitation and utilization of BPP for use as a surface-enhanced Raman scattering (SERS) substrate. According to the research results, the bilayer Ag NPs provide stronger plasmonic property and act as a light-matter coupler, so as to generate a large wave vector of scattered light and excite the BPP within the HMM. Besides, Ag NPs provide the nano antenna structure, and decouple the BPP into localized surface plasmon (LSP) that can be used directly to excite the electric fields. In addition, HMM produces a modulating effect on the plasmon resonance peak, which makes it possible to overlap the spectrum of resonance peak with excitation wavelengths, thus leading to a strong absorption peak at the incident laser wavelength region. Experimentally, the platform was applied to achieve SERS detection for adenosine molecules with a concentration of 10−6 M. It is believed that this plasmonic platform has a potential of application in surface-enhanced spectroscopy.
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Huang, Chien Wen, Yao Wu Hao, James Nyagilo, Digant P. Dave, Li Feng Xu, and Xian Kai Sun. "Porous Hollow Gold Nanoparticles for Cancer SERS Imaging." Journal of Nano Research 10 (April 2010): 137–48. http://dx.doi.org/10.4028/www.scientific.net/jnanor.10.137.
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Surface enhanced Raman spectroscopy (SERS) is a promising molecular imaging modality capable of simultaneously detecting multiple molecular biomarkers. With the biocompatibility and functionalizability of Au, Au-nanoparticle based Raman tags possess the potential for in vivo SERS cancer biomarker detection. Here, we report the large scale synthesis of a new type of Au nanoparticles, Porous Hollow Au Nanoparticles (PHAuNPs), and demonstrate their potential application as SERS imaging tags. PHAuNPs feature a sub-20 nm porous shell and a 50 nm void core. Such unique morphology enables them to strongly absorb and scatter near infrared lights due to the surface plasmon resonant effect of Au. This makes them particularly suitable for in vivo applications, where NIR wavelengths are considered as a ‘clear window’ for deeper penetration of light. The construction and characterization of PHAuNP-based Raman nanotag, including attachment of Raman dye, pegylation and their stability, are described. Cytotoxicity of Raman nanotags are tested using the radioactive [3H]thymidine incorporation method. The results show that pegylated Raman nanotags are stable and non-toxic and can potentially be used for in vivo applications.
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Xiaodan, Wei, Zheng Dawei, Zhang Ping, Lin Taifeng, Wang Huiqin, and Zhu Yongwei. "Surface-enhanced Raman scattering investigation of bovine serum albumin by Au nanoparticles with different sizes." Journal of Applied Biomaterials & Functional Materials 16, no. 1_suppl (2018): 157–62. http://dx.doi.org/10.1177/2280800017753055.
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Background: Surface-enhanced Raman scattering (SERS) has become a useful spectroscopic tool for studying biomolecule structures. The main types of plasmonic substrates used in biological systems are Au nanoparticles (AuNPs), whose surface plasmon resonance depends on the nanoparticle size, morphology, particle interspace, and so on. Methods: In this study, AuNP colloids with different sizes were synthesized and used as the sensors to probe SERS signals of different biomarkers and biomolecules. Results: The results showed that an AuNP colloid of ~50 nm had excellent SERS effects in probing various molecules, and could be preserved for about 3 months with excellent repeatability and reproducibility (RSD <5%) in terms of the probed signal intensity (rhodamine 6G and crystal violet). Meanwhile, the fabricated AuNPs were applied to study the SERS signals and structural information of bovine serum albumin (BSA) in aqueous solution. It was found that SERS could rapidly provide the structural information and vibration characteristics of BSA. Conclusion: It was concluded that biocompatible AuNP colloid may be a promising biosensor in the rapid and label-free detection of biological systems.
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Wang, Fengyan, Daxue Du, Shan Liu, et al. "Revealing the Hemispherical Shielding Effect of SiO2@Ag Composite Nanospheres to Improve the Surface Enhanced Raman Scattering Performance." Nanomaterials 11, no. 9 (2021): 2209. http://dx.doi.org/10.3390/nano11092209.
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Many studies widely used SiO2@Ag composite nanospheres for surface enhanced Raman scattering (SERS), which mainly contributes to electromagnetic enhancement. In addition to experiments, previous simulations mostly adopted a two-dimensional model in SERS research, resulting in the three-dimensional information being folded and masked. In this paper, we adopted the three-dimensional model to simulate the electric field distribution of SiO2@Ag composite nanospheres. It is found that when the Ag nanoparticles are distributed densely on the surface of SiO2 nanospheres, light cannot pass through the upper hemisphere due to the local surface plasmon resonance (LSPR) of the Ag nanoparticles, resulting in the upper hemisphere shielding effect; and if there are no Ag nanoparticles distributed densely on the surface of SiO2 nanospheres, the strong LSPR cannot be formed, so the incident light will be guided downward through the whispering gallery mode of the spherical structure. At the same time, we designed relevant experiments to synthesize SiO2@Ag composite nanosphere as SERS substrate and used Rhodamine 6G as a probe molecule to study its SERS performance. This design achieved a significant SERS effect, and is very consistent with our simulation results.
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Kim, Seokho, Bo-Hyun Kim, Young Ki Hong, et al. "In Situ Enhanced Raman and Photoluminescence of Bio-Hybrid Ag/Polymer Nanoparticles by Localized Surface Plasmon for Highly Sensitive DNA Sensors." Polymers 12, no. 3 (2020): 631. http://dx.doi.org/10.3390/polym12030631.
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We experimentally demonstrate the simultaneous enhancement of Raman and photoluminescence (PL) of core-shell hybrid nanoparticles consisting of Ag (core) and polydiacetylene (PDA, shell) through the assistance of localized surface plasmon (LSP) effect for the effective biosensor. Core-shell nanoparticles (NPs) are fabricated in deionized water through a sequential process of reprecipitation and self-assembly. The Raman signal of PDA on core-shell NPs is enhanced more than 100 times. Also, highly enhanced photoluminescence is observed on Ag/PDA hybrid NPs after coupling of the complementary t-DNA with p-DNA which are immobilized on PDA shell. This indicates that the core Ag affects the Raman and PL of PDA through the LSP resonance, which can be caused by the energy and/or charge transfer caused by the LSP coupling and the strong electromagnetic field near Ag NP surface. Only electrons present on the surface interact with the PDA shell, not involving the electrically neutral part of the electrons inside the Ag NP. Furthermore, this work shows that as prepared Ag/PDA NPs functionalized by probe DNA can sense the target DNA with an attomolar concentration (100 attomole).
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Villegas Borrero, Nelson Fabian, José Maria Clemente da Silva Filho, Viktor A. Ermakov, and Francisco Chagas Marques. "Silver nanoparticles produced by laser ablation for a study on the effect of SERS with low laser power on N719 dye and Rhodamine-B." MRS Advances 4, no. 11-12 (2019): 723–31. http://dx.doi.org/10.1557/adv.2019.157.
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ABSTRACTThe effect of surface-enhanced Raman spectroscopy (SERS) was investigated in N719 dye thin films deposited on silicon wafer with a thin film of silver nanoparticles (Ag-NPs) fabricated by laser ablation in an aqueous solution, using a NdYAG laser (λ = 1064nm). Optical absorption spectroscopy of the Ag-NPs colloidal solution shows an absorption peak at λ = 400nm, associated with a localized surface plasmon resonance in the Ag-NPs. Scanning electron microscopy (SEM) reveals that these NPs have an approximately spherical shape, with their diameter being tunable by laser power intensity. Raman spectroscopy measurements were performed using low laser power to avoid damage to the N719 dye films. Thus, a small Raman signal is obtained. The Raman intensity was greatly increased when the N719 film was deposited on a substrate with a thin film of Ag-NPs due to the SERS effect. The process was also used in Rhodamine-B to clearly demonstrate the SERS effect obtained by the use of these NPs produced by laser ablation.
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Zhou, Huayu, Jingjing Wang, Qiong Yang, et al. "Controllable Electrochemical Synthesis of Ag Hierarchical Micro/Nanostructures with High SERS-Activity." Nano 15, no. 04 (2020): 2050043. http://dx.doi.org/10.1142/s1793292020500435.
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We report a one-step electrochemical deposition technique to prepare three-dimensional (3D) Ag hierarchical micro/nanostructured film consisting of well-crystallized Ag nanosheets grown on an indium tin oxide (ITO) conductive substrate. The Ag hierarchical micro/nanostructures were fabricated in the mixed solution of AgNO3 and sodium citrate in a constant current system at room temperature. Through reduction of Ag[Formula: see text] electrodeposited on the surface of ITO substrate, nanoparticles were grown to form nanosheets which further combined into 3D sphere-like microstructures. The 3D Ag micro/nanostructures have many sharp edges and nanoscale gaps which can give rise to good Raman-enhanced effect. Due to localized surface plasmon resonance (LSPR) effects, these special Ag micro/nanostructures exhibited good Raman-enhanced performance. Using Rhodamine 6G (R6G) molecules as probe molecule, we studied the influence of excitation wavelength on Raman enhancement. The results showed that the 532[Formula: see text]nm excitation wavelength is the best to obtain the strongest Raman signal and to reduce the influence of other impurity peaks. Using the as-synthesized Ag hierarchical micro/nanostructures, we can detect the 10[Formula: see text][Formula: see text]mol/L R6G aqueous solution, exhibiting great Raman-enhanced effect.
Dissertations / Theses on the topic "Surface plasmon resonance. Raman effect, Surface enhanced. Nanoparticles"
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Khaywah, Mohammad Yehia. "New ultrasensitive bimetallic substrates for surface enhanced Raman scattering." Thesis, Troyes, 2014. http://www.theses.fr/2014TROY0041/document.
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Afin de développer des capteurs ultrasensibles des substrats fiables pour la diffusion Raman exaltée de surface (SERS) ont été fabriqués. Les deux meilleurs candidats de matériaux constituant les nanoparticules pour des substrats SERS sont l’argent et l’or. L’argent présente un meilleur facteur d’exaltation de l'intensité Raman et l’or est stable dans les milieux biologiques. C’est pourquoi la combinaison de ces deux métaux dans des nanostructures bimétalliques semble être une approche prometteuse qui combine les propriétés de surface de l’or et d’exaltation de l’argent. Le recuit thermique des couches métalliques minces est utilisé comme une technique simple et peu coûteuse. Cette dernière permet d’élaborer des substrats homogènes et reproductibles de nanoparticules bimétalliques or-argent ayant un facteur d’exaltation importante. Ces nanoparticules gardent leurs propriétés d’exaltation même après une année de fabrication. En jouant sur la composition de nanoparticules bimétalliques il est possible d’avoir une résonance de plasmons de surface localisés (LSPR) sur tout le spectre visible. Ces substrats sont caractérisés par une exaltation SERS supérieure lorsque la résonance plasmon est plus proche de la longueur d'onde d'excitation Raman. En outre, les nanoparticules bimétalliques de différentes tailles, compositions ont été réalisés par lithographie électronique. L’étude systématique de leurs propriétés plasmoniques et de leur exaltation SERS a révélé une conservation du lien entre résonance plasmon et signal SERS<br>Driven by the interest in finding ultrasensitive sensors devices, reliable surface enhanced Raman scattering (SERS) based substrates are fabricated. Silver and gold nanoparticles are two of the best candidates for SERS substrates where Ag nanoparticles exhibit large enhancing ability in Raman intensity while Au nanostructures are stable in biological systems. Hence, combining the two metals in bimetallic nanostructures appeared to be a promising approach in order to sum the merits of Au surface properties and Ag enhancing ability. Thermal annealing of thin metallic films is used as a simple and relatively inexpensive technique to elaborate homogenous and reproducible Ag/Au bimetallic nanoparticles SERS substrates with high enhancing ability. The fabricated nanoparticles proved their enhancing stability even after one year of fabrication. Manipulating the composition of Ag/Au bimetallic NPs resulted in tuning the Localized Surface Plasmon Resonance (LSPR) over the whole visible spectrum, where the substrates are characterized with higher SERS enhancement when they exhibit LSPR closer to the Raman excitation wavelength. Additionally, bimetallic nanoparticles patterns with different size, composition and lattice constants have been conducted by electron beam lithography. The systematic study of their interesting plasmonic and SERS enhancing properties revealed maintenance in the LSPR-SERS relation by changing the nanoparticle size
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Zin, Melvin T. "Self-assembly and nanofabrication approaches towards photonics and plasmonics /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/15502.
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Danilov, Artem. "Design, characterisation and biosensing applications of nanoperiodic plasmonic metamaterials." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0110/document.
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Cette thèse considère de nouvelles architectures prometteuses des métamatériaux plasmoniques pour biosensing, comprenant: (I) des réseaux périodiques 2D de nanoparticules d'Au, qui peuvent supporter des résonances des réseaux de surface couplées de manière diffractive; (II) Reseaux 3D à base de cristaux plasmoniques du type d'assemblage de bois. Une étude systématique des conditions d'excitation plasmonique, des propriétés et de la sensibilité à l'environnement local dans ces géométries métamatérielles est présentée. On montre que de tels réseaux peuvent combiner une très haute sensibilité spectrale (400 nm / RIU et 2600 nm / RIU, ensemble respectivement) et une sensibilité de phase exceptionnellement élevée (> 105 deg./RIU) et peuvent être utilisés pour améliorer l'état actuel de la technologie de biosensing the-art. Enfin, on propose une méthode de sondage du champ électrique excité par des nanostructures plasmoniques (nanoparticules uniques, dimères). On suppose que cette méthode aidera à concevoir des structures pour SERS (La spectroscopie du type Raman à surface renforcée), qui peut être utilisée comme une chaîne d'information supplémentaire à un biocapteur de transduction optique<br>This thesis consideres novel promissing architechtures of plasmonic metamaterial for biosensing, including: (I) 2D periodic arrays of Au nanoparticles, which can support diffractively coupled surface lattice resonances; (II) 3D periodic arrays based on woodpile-assembly plasmonic crystals, which can support novel delocalized plasmonic modes over 3D structure. A systematic study of conditions of plasmon excitation, properties and sensitivity to local environment is presented. It is shown that such arrays can combine very high spectral sensitivity (400nm/RIU and 2600 nm/RIU, respectively) and exceptionally high phase sensitivity (> 105 deg./RIU) and can be used for the improvement of current state-of-the-art biosensing technology. Finally, a method for probing electric field excited by plasmonic nanostructures (single nanoparticles, dimers) is proposed. It is implied that this method will help to design structures for SERS, which will later be used as an additional informational channel for biosensing
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Dorney, Kevin Michael. "A Chemical Free Approach for Increasing the Biochemical Surface-Enhanced Raman Spectroscopy (SERS)-Based Sensing Capabilities of Colloidal Silver Nanoparticles." Wright State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=wright1401206511.
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Wu, Tsunghsueh Shannon Curtis. "Surface plasmon assisted spectroscopies and their application in trace element analysis, the study of biomolecular interactions, and chemical sensing." Auburn, Ala., 2008. http://repo.lib.auburn.edu/EtdRoot/2008/SUMMER/Chemistry_and_Biochemistry/Dissertation/Wu_Tsung%20Hsueh_20.pdf.
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Khanafer, Maher. "Nanostructures métalliques organisées par auto-assemblage de polymère pour la détection d’espèces chimiques." Thesis, Troyes, 2015. http://www.theses.fr/2015TROY0003/document.
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Les avancées récentes de la nanofabrication ont permis de faire émerger un nouveau champ de recherche, celui des nanocapteurs. En particulier, le nanocapteur plasmonique dont le principe utilise l’effet SERS (Diffusion Raman Exaltée de Surface) commence à s’imposer. En effet, ce capteur permet d’amplifier la signature d’une molécule jusqu’à un facteur de 1012 et fournit une véritable empreinte digitale de chaque molécule. La sensibilité du capteur dépend des propriétés optiques des Nanoparticules Métalliques (NPMs) qui sont liées aux propriétés physiques et structurales de ces dernières. Ainsi, la maîtrise de la fabrication de NPMs est un réel défit pour des multiples applications nanotechnologiques. Dans ce contexte, nous avons développé une approche originale de fabrication de NPMs organisées par auto-assemblage de polymère. Il s’agit d’introduire de manière contrôlée des interactions physiques qui se manifestent lors de la fabrication par une nano-séparation de phase au sein du matériau. Ceci se traduit par un nanstructuration du polymère et une auto-organisation très spécifique du précurseur métallique qui se transforme spontanément en NPMs. Les investigations expérimentales en considérant les différents facteurs physico-chimiques impliqués, nous ont permis d’identifier les paramètres clés de cette structuration et de hiérarchiser leur influence sur les dimensions structurales et la réponse optique des NPMs. Finalement, la capacité du nanocapteur à détecter de faibles traces (<10-13 M) de polluants organiques a été démontrée<br>The recent advances in nanofabrication techniques have allowed for the emergence of novel sensing approaches. Amongst these various approaches, Surface Enhanced Raman Spectroscopy (SERS) via the use of plasmonic substrates has received wide-spread attention due to its many interesting proper-ties. In fact, plasmonic substrates enhance the Ra-man signal up to 12 orders of magnitude, paving the path for single molecule detection. Nevertheless, the sensitivity of this technique is strongly affected by the physical and structural properties of the metallic nanoparticles (MNPs). Thus, the mastering of the MNPs fabrication is a major challenge for various nanotechnological applications.In this context, we have developed a novel approach for the fabrication of organized NMPs through poly-mer self-assembly. The fabrication technique con-sists on controlling the physical interactions which occur during the fabrication through a nanophase separation in the polymer solution. This results in a nanostructuring of the polymer and a strong self-organization of the metallic precursor which is rapidly reduced into the MNPs. Experimental investigations of the different physical and chemical processes in play allow for a better understanding of the various keystone parameters of the nanostructuring as well as for determining their influences on the dimensions and optical response of MNPs. Finally, the fabricated plasmonic substrate demonstrated SERS limits of detection down to 10-13 M
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Ludemann, Michael. "In situ Raman-Spektroskopie an Metallphthalocyaninen: Von ultradünnen Schichten zum organischen Feldeffekttransistor." Doctoral thesis, Universitätsbibliothek Chemnitz, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-206568.
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Im ersten Teil der Arbeit werden Signalverstärkungsmechanismen für Raman-Spektroskopie erschlossen und evaluiert. Die als geeignet bewerteten Methoden finden im zweiten Teil ihre Anwendung zur Untersuchung der vibronischen Eigenschaften von dünnen Manganphthalocyaninschichten, die anschließend mit Kalium interkaliert werden. Hierbei sind verschiedene Phasen identifizierbar, die ein ganzzahliges Verhältnis von Kaliumatomen zu Manganphthalocyaninmolekülen besitzen. Im dritten Teil werden die elektrischen Eigenschaften durch die Verwendung dieses Materialsystems als aktives Medium eines Feldeffekttransistors untersucht.
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Shu, Tzu-Ching, and 徐子晴. "The Research of Silver Nanoparticle Array for Surface-Enhanced Raman Spectroscopy : The Effect of Molecular Concentration and Surface Plasmon Resonance." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/gds5f2.
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碩士<br>國立東華大學<br>物理學系<br>106<br>The main enhancement mechanism of Surface Enhanced Raman Scattering (SERS) is chemical strengthening mechanism and electric field enhancement mechanism. When two metal nanoparticles get very close, they will couple each other. There will be an electric field enhancement between two particles, called a hot spot. In this experiment, the silver nanoparticle solution were prepared by chemical reduction method. After that, the silver nanoparticles were surface-modified with 8-mercapto-octanoic acid (MOA) molecules. Finally, the modified silver nanoparticles were arranged into a fixed-pitch array by centrifugation. Using the method of immersion and titration, the Rhodamine (R6G) molecule is adsorbed on the sample. The R6G molecule enters the gap between the nanoparticles and enhances the SERS signal. The SERS signal intensity of different density of R6G molecules on the silver nanoparticles array was measured. We found that the SERS signal intensity did not increase continuously with the increase of R6G concentration. When the R6G density is lower than 1⤫10^3 (molecule/ μm^2), the SERS signal intensity and concentration will be positive correlation. We assumed that the number of R6G molecules distributed near the hot spots increase as the concentration increase. When the concentration of R6G is higher than 1⤫10^3 (molecule/ μm^2). Instead, the SERS signal slightly decrease with the increase of R6G density. We suppose that high R6G molecule density lead to R6G molecules overlapping. As a result, the SERS signal will be decreased. In the above experiments, we use the Raman excitation light of two different wavelengths as the light source. The measured SERS signal intensity will change overall. However, it will not affect variation trend of the R6G density and the SERS signal intensity. Previous simulation have shown that Raman excitation light of different wavelengths affect the degree of electric field enhancement between silver nanoparticles. Therefore, the variation of the SERS signal with density may be explained by the degree and extent of electric field enhancement of the hot spot.
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Faid, Rita. "Détection de protéines par diffusion Raman exaltée par effet de pointe (TERS)." Thèse, 2014. http://hdl.handle.net/1866/11462.
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La concentration locale des messagers chimiques sécrétés par les cellules peut être mesurée afin de mieux comprendre les mécanismes moléculaires liés à diverses maladies, dont les métastases du cancer. De nouvelles techniques analytiques sont requises pour effectuer ces mesures locales de marqueurs biologiques à proximité des cellules. Ce mémoire présentera le développement d’une nouvelle technique basée sur la réponse plasmonique sur des leviers AFM, permettant d’étudier les réactions chimiques et biologiques à la surface des leviers grâce au phénomène de résonance des plasmons de surface (SPR), ainsi qu’à la diffusion Raman exaltée par effet de pointe (TERS). En effet, il est possible de localiser l’amplification du signal Raman à la pointe d’un levier AFM, tout comme le principe de la diffusion Raman exaltée par effet de surface (SERS) basée sur la diffusion de la lumière par des nanoparticules métalliques, et permettant une large amplification du signal Raman. La surface du levier est recouverte d’une nano-couche métallique d’or, suivi par des réactions biologiques pour l’immobilisation d’un récepteur moléculaire, créant ainsi un biocapteur sur la pointe du levier. Une détection secondaire utilisant des nanoparticules d’or conjuguées à un anticorps secondaire permet également une amplification du signal SPR et Raman lors de la détection d’antigène. Ce mémoire démontrera le développement et la validation de la détection de l’immunoglobuline G (IgG) sur la pointe du levier AFM.Dans des projets futurs, cette nouvelle technique d’instrumentation et d’imagerie sera optimisée grâce à la création d’un micro-détecteur protéique généralement adapté pour l’étude de la communication cellulaire. En intégrant le signal SPR à la microscopie AFM, il sera alors possible de développer des biocapteurs SPR couplés à une sonde à balayage, ce qui permettra d’effectuer une analyse topographique et de l’environnement chimique d’échantillons cellulaires en temps réel, pour la mesure des messagers moléculaires sécrétés dans la matrice extracellulaire, lors de la communication cellulaire.<br>Measurement of the local concentration of chemical messengers secreted by cells may give a better understanding of molecular mechanisms related to different diseases, such as cancer metastasis. Current techniques are not suited to perform such measurements and thus, new analytical techniques must be developed. This Master’s thesis reports the development of a new technique based on the plasmonic response of atomic force microscopy (AFM) tips, which will ultimately allow monitoring of chemical and biological molecules on the surface of a cantilever by use of surface plasmon resonance (SPR) and tip-enhanced Raman scattering (TERS). Indeed, it is possible to localize the enhancement of the Raman signal on the AFM tip using principles associated to surface-enhanced Raman spectroscopy (SERS), based on the absorption of light by nanometer-sized metal particles, resulting in a large enhancement of the Raman signal. The AFM tip was constructed by the deposition of a nanometer-size gold layer, followed by the assembly of a biosensor with a biomolecular receptor. Gold nanoparticles (AuNPs) conjugated with a secondary antibody served as the secondary detection step. In addition, the use of the gold nanoparticles for antigen detection allows an amplification of the SPR and Raman signals. This Master’s thesis will demonstrate the development and validation of a biosensor for immunoglobuline G (IgG) at the tip of an AFM cantilever.This thesis sets the basis for future projects, where this new imaging technique will be developed for monitoring cellular communication by exploiting the plasmonic signal at the AFM tip. Different biosensors will then be developed and coupled to an AFM probe for scanning the chemical environment and detect in real-time chemical messengers secreted in the extracellular matrix in cellular communication.
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Swanglap, Pattanawit. "Single Particle Studies on the Influence of the Environment on the Plasmonic Properties of Single and Assembled Gold Nanoparticles of Various Shapes." Thesis, 2013. http://hdl.handle.net/1911/72045.
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Plasmonic nanoparticles and their assembly have the potential to serve as a platform in practical applications such as photonics, sensing, and nano-medicine. To use plasmonic nanoparticles in these applications, it is important to understand their optical properties and find methods to control their optical response. Using polarization-sensitive dark-field spectroscopy to study self-assembled nanoparticle rings on substrates with different permittivities I show that the interaction between collective plasmon resonances and the substrate can control the spatial scattering image. Using liquid crystals as an active medium that can be controlled with an external electric field I show that the Fano resonance of an asymmetric plasmonic assembly can be actively controlled utilizing the polarization change of scattered light passing through the liquid crystal device. Furthermore, utilizing the strong electromagnetic field enhancement of coupled plasmonic “nanospikes” on the surface of gold nanoshells with a silica core, I show the use of single spiky nanoshells as surface-enhanced Raman spectroscopy substrates. Individual spiky nanoshells give surprisingly reproducible surface-enhanced Raman spectroscopy intensities with a low standard deviation compared to clusters of nanoparticles. In summary, the work presented here provides understanding of the plasmonic response for assembled nanoparticles on different substrates, illustrated a new method to actively control the optical response of plasmonic nanoparticles, and characterizes spiky nanoshells as surface-enhanced Raman scattering platform.
Book chapters on the topic "Surface plasmon resonance. Raman effect, Surface enhanced. Nanoparticles"
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El-Kouedi, Mahnaz, and Christine D. Keating. "Biofunctionalized Nanoparticles for Surface-Enhanced Raman Scattering and Surface Plasmon Resonance." In Nanobiotechnology. Wiley-VCH Verlag GmbH & Co. KGaA, 2005. http://dx.doi.org/10.1002/3527602453.ch26.
Full textConference papers on the topic "Surface plasmon resonance. Raman effect, Surface enhanced. Nanoparticles"
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Adams, Sarah M., and Regina Ragan. "Gold Nanoparticle Self Assembly on Diblock Copolymers for Application as Biomolecular Sensors." In ASME 2010 First Global Congress on NanoEngineering for Medicine and Biology. ASMEDC, 2010. http://dx.doi.org/10.1115/nemb2010-13126.
Full textAbstract:
Current efforts in medical diagnostic technology focus toward developing biological sensors with the capacity for detecting trace quantities of specified organic molecules. In this study, metallic nanoparticles were investigated for the development of field-enhanced chemical and biological detection devices with the capacity to achieve single-molecule level detection resulting from surface enhanced Raman scattering (SERS) associated with closely spaced noble metal nanostructures.[1, 2] Localized surface plasmon resonance (LSPR) sensors likewise benefit from the incorporation of ordered metal nanoparticles on surfaces, providing increased shift in minimum of reflectivity with biological binding event (figure 1).[3]