Tesi sul tema "Spectroscopie Raman Exaltée par effet de Surface (SERS)"
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Reymond-Laruinaz, Sébastien. "Biomolécules et systèmes nanostructurés : caractérisation par spectrométrie Raman exaltée de surface (SERS)". Thesis, Dijon, 2014. http://www.theses.fr/2014DIJOS023/document.
Testo completoThis work addressed the study of several kinds of nanostructured systems, biomolecules and inorganic thin films, mainly by Surface Enhanced Raman Spectroscopy (SERS). The aim was to investigate the structure and the chemical bonds. Transmission electron microscopy (TEM) was also used to complete the structural characterization of the different samples.Firstly, the study was conducted on molecules of biological interest. The aim was to study the interaction between silver nanoparticles and proteins. With this aim, silver nanoparticles bioconjugated with different proteins (hemoglobin, cytochrome C, BSA and lysozim) were synthesized. SERS results allowed concluding that proteins are chemisorbed on the silver nanoparticules surface. SERS was also used in the low frequency range to characterize the structure of thin deposits of caffeine, a molecule of pharmaceutical interest.Raman spectroscopy and SERS were also used to study nanostructured TiO2:Au thin films. The first stages of the growth of gold nanoparticles in Au doped TiO2 thin films under annealing treatments were studied by low frequency Raman spectroscopy and TEM. Finally, it was shown that SERS effect can be used for the characterization of ultra-thin TiO2 films. With this aim, ultra-thin TiO2 films were deposited by Atomic Layer Deposition on Si substrates functionalized with gold nanoparticles and studied by SERS
Siskova, Karolina. "Elaboration de nouvelles nanostructures d'Argent, obtenues par abblation laser, pour caractériser des macro- et biomolécules par spectroscopie Raman exaltée par effet de surface". Paris 6, 2006. http://www.theses.fr/2006PA066509.
Testo completoTouzalin, Thomas. "Tip-enhanced Raman spectroscopy on electrochemical systems". Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS364.
Testo completoThe in situ investigation of electrochemical interfaces structures at the nanoscale is a key element in the understanding of charge and electron transfer mechanisms e.g. in the fields of energy storage or electrocatalysis. This thesis introduces the implementation of tip-enhanced Raman spectroscopy (TERS) in liquid and in electrochemical conditions enabling the nanoscale analysis of electrified solid/liquid interfaces through the strong and local electric field enhancement at gold or silver scanning tunneling microscopy (STM) probes. The ability of TERS to image inhomogeneities in the coverage density of a self-assembled monolayer (SAM) through a layer of organic solvent on gold was demonstrated. A TERS-inspired analytical tool was also developed, based on a TERS tip used simultaneously as a single-hot spot surface-enhanced Raman spectroscopy (SERS) platform and as a microelectrode (EC tip SERS). The reduction of an electroactive SAM could then be monitored by electrochemical and in situ SERS measurements. In situ electrochemical STM-TERS was also evidenced through the imaging of local variations of the electric field enhancement on peculiar sites of a gold electrode with a lateral resolution lower than 8 nm. Finally TERS also demonstrated to be efficient in investigating the structure of organic layers grafted either by electrochemical reduction or spontaneously. This work is therefore a major advance for the analysis of functionalized surfaces
Hachin, Axelle. "Développement d'une plateforme de détection SERS à partir de monocouches auto-assemblées". Electronic Thesis or Diss., Bordeaux, 2023. http://www.theses.fr/2023BORD0481.
Testo completoBiosensors are real-time detection systems for biological species widely used in diagnostics. Surface Enhanced Raman Spectroscopy (SERS), with its specific and sensitive identification capability, is a good way of detecting biomolecules (aptamers, peptides, etc.) using suitable surfaces (such as metal nanostructures, nanoparticles, etc.). With a view to developing a SERS biosensor, a detection platform based on self-assembled monolayers (SAMs) functionalized with spherical or cylindrical gold nanoparticles was designed. The thesis work consisted in producing SAMs based on organosilane bearing an azide or amine terminal function. The SAMs were then modified by reaction with linkers, either by peptide coupling or click chemistry, to provide thiol or cyclooctyne end functions. These modifications are characterized by various techniques such as PM-IRRAS, AFM, XPS or ToF-SIMS. Gold nanoparticles have been successfully immobilized by two different routes: on azide-terminated SAMs by click chemistry and on thiol-terminated SAMs by ligand exchange. Promising initial results have been obtained demonstrating SERS detection of the bioreceptor immobilized on the nanoparticles
Aybeke, Ece Neslihan. "Study of the dynamics of biomolecules by high speed atomic force microscopy and surface enhanced Raman spectroscopy". Thesis, Dijon, 2015. http://www.theses.fr/2015DIJOS023/document.
Testo completoThis thesis focuses on the coupling of High–Speed Atomic Force Microscopy (HS-AFM) and Surface Enhanced Raman Spectroscopy (SERS) for biomolecule analysis. We have designed a fabrication protocol to manufacture “SERS-active” substrates. The efficacy of gold, silver and gold-silver bimetallic crystalline nanoparticle substrates were evaluated. We have investigated the impact of optical and morphological features of the substrates on Raman signal intensity by analyzing well-known samples such as bipyridine ethylene and methylene blue molecules. We took an interest in three distinct biological problematics with HS-AFM and SERS analyses. First, we have detected the chemical signature of cytochrome b5 protein. This study was followed by the investigation of conformational changes of small heat shock leuconostoc oenos Lo 18 protein in function of pH level and concentrations. The last application consists to the analyse a membrane and a virus interaction. In order to realize simultaneous Raman/AFM analysis, we have adapted our fabrication protocol to cover the surface of commercial AFM probes by crystalline gold nanoparticles. Tip – Enhanced Raman Spectroscopy (TERS) studies were performed on molybdenum disulfide to evaluate the quality of TERS probes. In the last part of this work, we have designed a new setup to combine Ando’s HS-AFM setup with Raman spectroscopy. We present the modifications that have been carried out and the challenges that we have encountered
Andrei, Cassiana. "Détection directe et sélective de bactéries par imagerie Raman exaltée de surface". Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLX065.
Testo completoRapid detection of bacterial pathogens is an important challenge nowadays in multiple fields like in food industry, health and military biodefense. Biosensors are promising candidates for replacing time consuming and expensive classical tools. In this work, we developed biosensors based on hydrogenated amorphous silicon layer for the covalent grafting of probes (antibodies or sugars) interacting specifically with bacteria, and noble metal nanoparticles for spectroscopic identification of trapped bacteria by surface enhanced Raman spectroscopy (SERS). In a first approach, the production of stable and cost-effective SERS-active substrates based on metallic thin films was proposed for the study of various bacteria. Different SERS fingerprints of three different strains of the same bacteria were obtained allowing their discrimination, result confirmed by principal component analysis (PCA). In a second approach, SERS study of bacteria was performed using nanoparticles colloids, positively charged gold nanorods showing the best reproducibility. In parallel, the optimization of probes grafting on the amorphous silicon surface and of the blocking step for minimization of non-specific adhesion of bacteria were performed. Finally, tests with the entire architecture of the biosensor were performed and by using a fluidic cell the attachment of bacteria was monitored in situ. After contact with gold nanorods the specific identification of bacteria by SERS was possible. Using this strategy limits of detection up to 10 cfu/mL were achieved in a total time of detection of 3 h
Chapus, Lionel. "Organisation de nanoparticules de métaux nobles : application à la spectroscopie Raman exaltée de surface et à l'électrochimie". Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066258/document.
Testo completoMetallic nanoparticles (NPs) have been subjected to a growing interest these last years in various domains such as healthcare, environment or electronics. In this thesis, we were particularly interested in the application of NPs mono or bimetallic made of noble metals in plasmonic domain. In this way, we synthesized by organometallic route, monometallic NPs of gold, silver and copper with a diameter ranging from 5 to 11 nm and characterized by a narrow polydispersity. After deposition on a solid substrate, they organized themselves spontaneously in 3D forming individual supercrystals. We studied the optical properties of these supercrystals, by measuring their absorbance spectra in function of their thicknesses and the nature of the NPs. Then, we showed that these supercrystals can be used as SERS substrates. The mean diameter of the NPs is way smaller than the ones reported in the literature. These substrates display a uniform and reproductible signal from a supercrystal to another. The Raman spectra of coating agent (alkanethiols or alkylamines) have been collected and enhancement factor ranging from 103 to 104 have been calculated. After verification by electroreflectance of NPs stability over a wide potential range, we coupled SERS with electrochemistry by using a monolayer of organized gold NPs as an electrode. Coverage rates for two different molecules adsorbed on the NPs have been calculated. Moreover, we could follow and confirm the species formation during the oxydoreduction reactions of the adsorbed molecules by SERS. Finally, we synthesized core-shell NPs Au@Ag, Ag@Au and alloy NPs Cu-Au by using gold, silver and copper NPs as seeds. Their structures and chemical compositions have been studied. Their optical spectra have been measured by UV-Visible spectroscopy and simulated by DDA (Discrete Dipole Approximation). They confirmed the core-shell and alloy structures. By low frequency Raman spectroscopy, for the Au@Ag NPs, we showed a coupling between the core and the shell in accordance with the core-shell model developed in the literature. For the Cu-Au NPs, low-frequency Raman signal is in agreement with the formation of an alloy
Le, Nader Victor. "Approche expérimentale et théorique de la diffusion Raman exaltée : résonance des plasmons de surface et effet de pointe". Phd thesis, Université de Nantes, 2010. http://tel.archives-ouvertes.fr/tel-00559365.
Testo completoKaya, Zeynep. "Controlled and localized synthesis of molecularly imprinted polymers for chemical sensors". Thesis, Compiègne, 2015. http://www.theses.fr/2015COMP2220.
Testo completoMolecularly imprinted polymers (MIPs), also referred to as plastic antibodies, are synthetic biomimetic receptors that are able to bind target molecules with similar affinity and specificity as natural receptors such as enzymes or antibodies. Indeed, MIPs are used as synthetic recognition elements in biosensors and biochips for the detection of small analytes and proteins. The molecular imprinting technique is based on the formation of specific recognition cavities in polymer matrices by a templating process at the molecular level. For sensor and biochip development, fast binding kinetics of the MIP for a rapid sensor response, the integration of the polymers with transducers, and a high sensitivity of detection are among the main challenges. In this thesis, the above issues are addressed by developing MIP/gold nanocomposites by grafting MIPs on surfaces, using dedicated techniques like atom transfer radical polymerization (ATRP) which is a versatile controlled radical polymerization (CRP) technique. Theses ophisticated CRP techniques, are able to greatly improve the polymeric materials. The use of ATRP in the MIP field has been limited so far due to its inherent incompatibility with acidic monomers like methacrylic acid (MAA), which is by far the most widely used functional monomer. Herein, a new method is described for the MIP synthesis through photo-initiated ATRP using fac-[Ir(ppy)3] as ATRP catalyst. The synthesis is possible at room temperature and is compatible with acidic monomers. This study considerably widens the range of functional monomers and thus molecular templates that can be used when MIPs are synthesized by ATRP. The proposed method was used for fabrication of hierarchically organised nanocomposites based on MIPs and nanostructured metal surfaces containing nanoholes or nanoislands, exhibiting plasmonic effects for signal amplification. The fabrication of nanometer scale MIP coatings localized on gold surface was demonstrated. Optical transduction methods, namely Localized Surface Plasmon Resonance (LSPR) and Surface Enhanced Raman Spectroscopy (SERS) were exploited and shown that they hold great promise for enhancing the limit of detection in sensing of biologically relevant analytes including proteins and the drug propranolol
Tchinda, Sonhapi Arielle. "Analyse Conformationnelle des Protéines en Réponse à l'Environnement (pH et Température) par Spectroscopie Raman Exaltée en Surface (SERS)". Electronic Thesis or Diss., Bourgogne Franche-Comté, 2023. http://www.theses.fr/2023UBFCK080.
Testo completoThe thesis presented offers an in-depth exploration of protein structures and behaviors, with a particular focus on their interactions with colloidal gold nanoparticles. To analyze protein modifications in response to variations in pH and temperature, Arielle utilizes Surface-Enhanced Raman Spectroscopy (SERS) techniques as well as microfluidics.The analysis of protein secondary structure, using bovine serum albumin (BSA) as a model, reveals close links with the overall protein conformation. Changes in pH and temperature result in significant conformational alterations, visible in the analysis of amides I, II, and III. Furthermore, the study is not limited to well-structured proteins but also encompasses intrinsically disordered proteins (IDPs), which adopt flexible conformations in response to their environment, thus expanding our understanding of the structural complexity of proteins.Exploring protein-nanoparticle interactions serves as a basis for understanding how this structural diversity translates into a variety of biological functions. Arielle employs an innovative approach based on Markov chains to analyze protein disorder, providing a comprehensive view of protein flexibility and plasticity, with successful applications to BSA and alpha-synuclein.Finally, the thesis underscores the importance of understanding conformational dynamics at the single-protein level in biological processes, with potential implications for medical and biotechnological advancements
Delhaye, Caroline. "Spectroscopie Raman et microfluidique : application à la diffusion Raman exaltée de surface". Thesis, Bordeaux 1, 2009. http://www.theses.fr/2009BOR13927/document.
Testo completoThis thesis focuses on the development of a microfluidic platform coupled with confocal Raman microscopy, used in excitation conditions of Raman scattering (Surface enhanced Raman scattering, SERS) in order to gain in the detection sensitivity of molecular species flowing in channels of micrometer dimensions. This work aims to demonstrate the feasibility of coupling Raman microscopy / microfluidics for the in situ and local characterization of species and reactions taking place in the fluid flowing in microchannels. We used a T-shaped microchannel, made by soft lithography, in which gold or silver nanoparticles injected at constant speed, in one of the two branches of the channel and a solution of pyridine or pefloxacin in the other one. The laminar flow and the stationarity of the process allowed us to map the mixing zone and highlight the enhancement of the Raman signal of pyridine and pefloxacin, due to the metallic nanoparticles, in the interdiffusion zone. The recording of the both absorption band of the silver nanoparticles (plasmon band) and the Raman signal of pefloxacin, flowing in microchannel, allowed us to establish a link between the shape of the metallic nanostructure, and more precisely the silver nanoparticle aggregation state, and the enhancement of the Raman signal of pefloxacin observed. We then changed the channel geometry to introduce an electrolyte solution (NaCl and NaNO3) and locally modify the surface charge of the colloids. We have put in evidence that the change of the silver nanoparticle aggregation state, induced by the controlled addition of electrolyte solutions, could amplify the SERS signal of pefloxacin and thus optimizing the detection in microfluidics. At last, we established second a approach that consists in the metallic structuring of microchannel walls. This has shown that the surface chemical functionalization through organosilanes (APTES) allowed the pasting of the channel with silver nanoparticles, thus amplifying the Raman signal of the species flowing within the same microchannel
Grand, Johan. "Plasmons de surface de nanoparticules : spectroscopie d'extinction en champs proche et lointain, diffusion Raman exaltée". Troyes, 2004. http://www.theses.fr/2004TROY0014.
Testo completoThe intrinsic weakness of the Raman process makes its application in a near field optical experiment rather difficult. Thus, as a first step towards near field Raman spectroscopy, we studied Surface-Enhanced Raman Scattering (SERS), a technique that enables the detection of very low concentration of molecules adsorbed on rough metallic surfaces. For the purpose of the near field experiments, these SERS-active samples have to be reproducible and yield good enhancement factors. By designing metallic nanoparticle grating through electron beam lithography, we manage to vary the shape, size and arrangement of the particles, hence enabling a fine tuning of the Localized Surface Plasmon Resonance (LSPR) over the whole visible spectrum. We then investigate the relationship between the spectral position of the LSPR and the SERS intensity. The enhancement factor turned out to depend not only on the spectral position of the LSPR, but also on the shape of the metallic nanoparticles on which the surface plasmon is localized. In the same time, we build up an Apertureless Scanning Near Field Optical Microscope (ASNPM) set-up. The microscope is based on an atomic force microscope and a confocal detection coupled to a spectrometer. The near field/far field discrimination is achieved through the use of a lock-in detection of a photon counting device. Using this set-up along with a white light continuum, generated by coupling a Photonic Crystal Fiber to a Ti:Sa laser, made it possible to investigate the near field optical response of metallic nanoparticle gratings at different excitation wavelengths. A photon counting scheme was then used to directly record near field “extinction” spectra
Yazidi, Senda. "Structure et propriétés optiques de nanoparticules couplées : application à la spectroscopie Raman exaltée de surface". Thesis, Poitiers, 2018. http://www.theses.fr/2018POIT2279/document.
Testo completoThe aim of this work is to use nanostructured alumina surfaces to guide the growth and to optimize the organization of metallic particles (Ag, Au and AgxAu1-x), and to test those systems as reusable SERS-active substrates. We used spectrophotometry to characterize the resulting optical properties, spectroscopic ellipsometry for the determination of the optical index and transmission electron microscopy for the structural characterizations. Surfaced-enhanced Raman spectroscopy (SERS) was used for the detection of adsorbed bipyridine molecules on the sample surface, in collaboration with the Institut des Matériaux Jean Rouxel at Nantes. We first study systems consisting of monometallic and bimetallic nanoparticles in order to understand the growth modes of such particle assemblies. A particular attention is paid to the influence of the sequential deposition of Au and Ag on the structural and optical properties. We show that different arrangements of bimetallic nanoparticles are obtained according to the deposition sequence used and that an alloy is obtained after ex situ annealing under vacuum. The near-field and far-field optical properties of AgxAu1-x nanoparticle alloys embedded in an alumina matrix are compared numerically by the finite difference time domain method, with those of pure metal nanoparticles. Our results indicate that pure metal nanoparticles exhibit a greater field enhancement than alloy nanoparticles. Finally, SERS experiments conducted with a dichroic system made of coupled Ag nanoparticles show that an intense SERS signal can be obtained with coated nanoparticles
Beffara, Flavien. "SERS biosensors based on special optical fibers for clinical diagnosis". Thesis, Limoges, 2021. http://www.theses.fr/2021LIMO0009.
Testo completoDespite important breakthroughs in biosensing, we are still in need of new sensors that would facilitate the early detection of severe diseases such as cancer. Classical tissue biopsy remains the gold standard in many cases. Although this approach has shown its potential, it remains invasive for the patients and the detection techniques are either tedious or lack the sensitivity to detect the disease at an early stage. Raman spectroscopy has demonstrated its interests for biosensing. Its ability to characterize the chemical nature, structure and the orientation of an analyte makes it an ideal candidate. The sharp Raman peaks of a molecule can be seen as a true fingerprint. Regrettably, Raman scattered signal is extremely weak. This limitation was overcome by surface enhanced Raman spectroscopy (SERS), since it drastically increases the Raman scattered signal while maintaining the sharp peak of the fingerprint spectrum of a molecule. Unfortunately, most of the current SERS substrates are 2D nano-roughened metal surfaces or colloidal nanoparticles, which lack the sensitivity and reliability in measurement with poor repeatability and reproducibility in the data. In the recent years, special optical fibers have been used as SERS platforms. They feature holes that run along their entire length. These holes allow for the analyte to be incorporated inside the fiber. Thus, such platform represents a promising alternative to planar substrates since the analyte and the excitation light can interact for longer length inside the fibers. In addition, optical fibers are very flexible, compact and allow for low-loss light guiding. Therefore, such fiber sensors exhibit the outstanding detection abilities of SERS, the advantages of optical fibers and improved sensitivity and reliability. In this manuscript, we aim to create a biosensing platform that could be routinely used in a clinical setting. For that, we propose to optimize the features of an already reported fiber topology. This allows us to increase its sensitivity while simultaneously improving its reliability and practicability. With this improved sensor, for the first time, we could detect the biomarker for ovarian cancer in clinical cyst fluids, which allowed us to differentiate the stage of the cancer. Subsequently, we propose a novel fiber topology, specifically designed to further increase the sensitivity of SERS-based fiber probes. This is achieved by increasing the surface of interaction compared to standard fiber sensors. For that, the core diameter is significantly increased and the amount of light that interacts with the analyte is precisely controlled. We envision that such functionalized fiber sensors could be incorporated inside a biopsy needle to create a two-in-one sensor for body fluid collection and readout that can eventually overcome the limitations associated with existing biopsy needle platforms, which demands for two-step sample collection and readout
Guillot, Nicolas. "Propriétés optiques de nanoparticules métalliques et application aux nanocapteurs par exaltation de surface". Phd thesis, Université Paris-Nord - Paris XIII, 2012. http://tel.archives-ouvertes.fr/tel-00844312.
Testo completoGuillot, Nicolas. "Propriétés optiques de nanoparticules métalliques et application aux nanocapteurs par exaltation de surface". Phd thesis, Paris 13, 2012. http://www.theses.fr/2012PA132048.
Testo completoThe work presented in this manuscript focuses on the different possibilities leading to the optimization of the signal of localized surface plasmon resonance (LSPR) basednanosensors and fabricated by some techniques enabling a precise control of the geometry of metallic nanostructures. Nanosensors based on LSPR and surface enhanced Raman scattering (SERS) have been especially studied. The first part of this manuscript reminds the key parameters leading to the optimization of the signal of such nanosensors, i. E. , the nanostructures material, the size and the shape of the nanostructures, the surrounding medium, the incident electric field polarization, the gap between the nanoparticles and the higher order LSPR. The second part is focused on SERS nanosensors by exposing the optimization principle and possibilities of the signal in the case of arrays of gold nanoparticles. Finally, the last part is devoted to the observation of the shape of the local electromagnetic field around the nanoparticles (amplitude and decay length) by the study of the near-field coupling between gold nanoparticles of different shapes
Hübner, Jakob. "Structure investigations of energetic and pharmaceutical nanoscale composites via AFM-TERS and SERS". Thesis, Strasbourg, 2020. http://www.theses.fr/2020STRAE009.
Testo completoTip Enhanced Raman Spectroscopy based on Atomic Force Microscopy (AFM-TERS) is applied to study the structure of diverse nanoscale energetic and pharmaceutical composites. AFM-TERS investigations of nanoscale CL-20/HMX co-crystals demonstrate that CL-20/HMX surfaces consist of a molecular layer of HMX. Experimental results are supported by an approximation of vibrational normal coordinates allowing to exclude the appearance of relatively strong HMX Raman intensities because of a specific arrangement between CL-20/HMX nano co crystals and the Raman scattering systems. Diverse nanoscale RDX and TNT mixtures differing in their weight percentage ratio are analyzed with AFM-TERS. The combination of far-field Raman spectroscopy and surface sensitive TERS enabled the identification of anisotropic RDX/TNT core/shell nanoparticles. Submicron Furosemide-PVP particles are investigated by confocal far-field Raman microscopy and Surface Enhanced Raman microscopy. Furosemide-PVP particles are directly sputtered with thin layers of silver. The comparison of far- and near-field Raman spectra reveals that shells of PVP encapsulate Furosemide cores
Rahmani, Meryem. "Analyses Raman multispectrales exaltées pour la détection de molécules sous forme de trace". Electronic Thesis or Diss., Le Mans, 2024. http://www.theses.fr/2024LEMA1004.
Testo completoIn recent decades, the use of phytosanitary products commonly called pesticides has increased. These substances have become increasingly present in our environment, accumulating in soil, air and water. Even at very low concentration these products represent a danger to human, plant and animal health. For all these reasons it is important to regulate the use of phytosanitary products by prohibiting the use of certain of these substances and by strengthening regulations to set Maximum Residue Limits (MRLs) as low as possible. It is also necessary to develop new methods for detecting and identifying trace pollutants because conventional techniques require large laboratory capabilities which are not compatible with on-site analyses.In my PhD. work, we have used Surface Enhanced Raman Scattering (SERS) to detect and identify trace molecules. We studied and analyzed the performance of three commercial DRES substrates (Hamamatsu, SERSitive and Ocean Insight) for the detection and identification of a model molecule at concentrations of the order of 10-6 M and 10-8 M. We compared the Raman responses from the Raman maps recorded on their surfaces at two incident wavelengths. We have also developed and optimized efficient nanorough metallic substrates to detect and identify molecules with a detection limit of 10-9 M. We will present the experimental protocol used to fabricate our nanorough gold substrates. The topographical properties of the surfaces were studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM) to better understand the reason of SERS properties of the substrates. The optical responses of our nanorough substrates were studied in the near field by electron photoemission (PEEM) and in the far field by Raman spectrometry after putting them in contact with solutions containing molecules at very low concentrations. We compared the spectral response, intensity distributions, and stability under laser beam, of gold nanorough substrates and the most efficient substrate among the three commercial DRES substrates by analyzing the Raman spectra at a concentration of 10-8 M.The stability of the Raman response of the commercial SERS substrates and our optimized nanorough substrates was studied over time, for a period of several months. The effectiveness of the substrates decreases over time and it is no longer possible to detect the presence of the molecules after several months. In my PhD work we have tested a method that makes it possible to improve the Raman performance of these aged substrates. The performance of these improved substrates was studied by analyzing Raman intensity distributions from imaging containing several hundred spectra. Finally, we used the gold nanorough substrates to detect molecules present in a binary mixture of model molecules at a concentration of 10-8 M. We analyzed the Raman maps using chemometric tools, namely Component Analysis. Principal (ACP), and Multivariate Curve Resolution (MCR)
Eschimese, Damien. "Design, fabrication, and characterization of TIP-enhanced Raman spectroscopy probes based on metallic nano-antennas". Thesis, Lille 1, 2019. http://www.theses.fr/2019LIL1I020/document.
Testo completoSince the start of the 2000s the evolution of tip-enhanced Raman spectroscopy (TERS) has enabled the simultaneous measurement of localized structural, molecular, and physicochemical properties. TERS technology combines scanning probe microscopy -- atomic force microscopy (AFM) -- with near field optical microscopy. The combined technique is referred to as AFM-TERS. The technique harnesses and exploits the generation of surface plasmons on metal surfaces. These plasmons lead to the generation of confined electromagnetic waves in a sub-wavelength volume at the very tip of the AFM-TERS probe. The main technological challenge today is the design and optimization of an AFM-TERS probe having nanometer-sized dimensions -- and the controlled, reproducible batch fabrication of such structures. The objective of the work presented in this PhD thesis was to design, fabricate, and characterize a new type of AFM probe capable of bettering the current state-of-the-art performances. The PhD was carried out in collaboration with HORIBA and funded partly by a French ‘CIFRE’ grant. In order to meet these objects, comprehensive numerical modelling led to the design of an optimized metal nanostructuring having maximum electromagnetic exaltation -- placed at the extremity of a silicon-based AFM cantilever. A new combined micro and nano fabrication process was developed to achieve this -- to be performed using the existing equipment found in the IEMN cleanroom. The process encompasses techniques such as masking using electron beam (ebeam) lithography and UV photolithography, thermal evaporation of metals and ‘lift-off’ techniques, and highly-controlled dry etching of small silicon mesas structures and deep etching for MEMS cantilever releasing. The process enables the batch-fabrication manufacture of AFM-TERS probes containing matter on the millimeter scale (the silicon probe support), the micrometer scale (the silicon cantilever), and the nanometer scale (the combined metallic disk and cone having sub-wavelength dimensions). This method allows nanostructuring on the optical/plasmonic behavior of TERS probes, the key factor which will lead to higher performance in TERS. Finally, a further study concerning the inclined evaporation of metallic nanostructures via an ebeam-derived lithographic shadow mask was performed in order to control the size and shape of the nanostructuring. The study proved this approach to be feasible. Furthermore, numerical modelling of such structures suggests that they are potential original candidates for both TERS and SERS (surface-enhanced Raman spectroscopy)
Rastogi, Rishabh. "Engineered Electromagnetic Hot-spots for Highly Sensitive (Bio)molecular Detection by Plasmonic Specytroscopies". Thesis, Troyes, 2020. http://www.theses.fr/2020TROY0018.
Testo completoNanoplasmonic sensing relies on enhanced electromagnetic fields at the vicinity of nanostructured metal surface to detect molecules at ultra-low concentrations. The EM enhancements are strongly pronounced at junctions between adjacent nanostructures resulting in gap hot-spots. EM enhancements at these hot-spots increase non-linearly as a function of gap distances down to sub-10 regime. Analyte present at these gaps can leverage these EM enhancements, resulting in ultra-high sensitivity in detection. However, such confining gaps affect the ability of large analytes such as biomolecules to enter and thereby leverage EM fields within the gaps. This presents spatial needs to enhance EM fields at odds with those for accommodating biomolecular interactions. This thesis demonstrates the rational design of array configurations that allows the EM hotspots to be better leveraged by the reporter of biomolecular binding event. The thesis uses molecular self-assembly based approach to fabricate reproducible plasmonic nanoarrays on full wafers. Multiple parameters are considered including the dimension, shape, and density of hotspots, surface functionalization, and the choice of substrates, to demonstrate quantitative detection of molecules down to picomolar concentrations
Lussier, Félix. "Optophysiologie SERS : analyse in vitro d’environnement cellulaire en Raman exalté par les surfaces". Thèse, 2019. http://hdl.handle.net/1866/22631.
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