Dissertationen zum Thema „Metallic nanoparticules“
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Brandstetter-Kunc, Adam. „Decay of plasmonic excitations in one dimensional assemblies of metallic nanoparticules“. Thesis, Strasbourg, 2016. http://www.theses.fr/2016STRAE042/document.
Der volle Inhalt der QuelleWe studied the electron dynamics in metallic nanoparticle arrays. We first considered the simplestarray i.e. a nanoparticle dimer. We found the eigenfrequencies of the heterogeneous dimer andthen we applied the open quantum system approach to describe the decay processes present inthe system. We investigated two decay processes which depend on the size of the nanoparticlesbuilding up the dimer : the Landau damping, inversly proportional to the system-size, and radiationdamping, proportional to the volume of the system. Using the results of the dimer study weextended our open quantum system approach to study one-dimensional nanoparticle chains. Wederived a master equation and used it to investigate the propagation of plasmons along the chain.We found that the propagation of the plasmon is limited by the non-radiative sources of damping.Finally we derived an analytical expression for the propagation length of a plasmon in ananoparticle chain
Helgadottir, Inga. „Synthèse Contrôlée de Nanoparticules de Métaux Oxophiles en Milieu Liquide lonique pour Applications en Microélectronique“. Thesis, Lyon 1, 2013. http://www.theses.fr/2013LYO10286.
Der volle Inhalt der QuelleSmall size (below 10 nm) metallic nanoparticles and metallic nanoalloys have attracted much interest in a range of applications, which require precise control of size, composition, and morphology, in chemically significant quantities. Hence, the variety of compositions and structures (size, morphology, atomic arrangement) bring a vast range of possibilities. This PhD was aimed at expanding the knowledge already obtained in this laboratory on monometallic nanoparticles. Indeed, it has been demonstrated that the decomposition of organometallic precursors in selected ionic liquids can lead to the formation of stable suspensions of metallic nanoparticles below 5 nm. In this context, a first achievement in this work has been to push this route towards more oxophilic, less approachable metals, such as tantalum. Besides, this route has been shown to generate bimetallic nanoparticles upon decomposition of mixtures of precursors, with size, structure and composition controlled, such as Ru@Cu. This PhD work has dentified the mechanism of formation of these nanoalloys, developing a versatile route that could be used to design nanoalloys to fulfill specific applications, e.g., RuNi, RuTa, CuNi, etc
Weick, Guillaume. „Quantum dissipation and decoherence of collective excitations in metallic nanoparticles“. [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=981745679.
Der volle Inhalt der QuelleAyvali, Tugçe. „Rhenium based mono- and bi-metallic nanoparticles : synthesis, characterization and application in catalysis“. Thesis, Toulouse 3, 2015. http://www.theses.fr/2015TOU30269/document.
Der volle Inhalt der QuelleIn this PhD thesis, the synthesis, characterization and preliminary catalytic application of rhenium based mono- and bi-metallic nanoparticles are reported. Rhenium has been chosen as a primary metal given the knowledge of its positive contribution in terms of catalytic activity and selectivity in the hydrogenation of difficult functional groups. Mono-metallic rhenium nanoparticles were prepared by decomposition of [Re2(C3H5)4]. Rhenium-based bimetallic nanoparticles were synthesized by co-decompositions or two-step decomposition of two different rhenium complexes, namely [Re2(CO)10] and [Re2(C3H5)4], with other organometallic complexes such as [Ru(COD)(COT)], [Ru(Me-Allyl)2(COD)], [Pt(CH3)2(COD)] and [Pt(C7H10)3]. By tuning the nature of organometallic complexes and the reaction conditions, rhenium-based bimetallic nanoparticles displaying different morphologies could be quantitatively prepared. The synthesis was carried out in solution under mild pressure of dihydrogen (3 bar) and in the presence of either a polymer (polyvinylpyrolidone) or a weakly coordinating ligand (hexadecylamine) as stabilizing agents. The precise characterization of the so-obtained nanoparticles was performed by using a combination of state-of-the art techniques (WAXS, EXAFS, TEM, HRTEM, STEM-EDX, STEM-HAADF, EA). Surface reactivity studies (norbornene hydrogenation, oxidation and CO adsorption reactions) were also carried out and followed by spectroscopic techniques (NMR, FT-IR) to determine their surface state and apprehend better their interest in catalysis. By this way, useful information could be obtained on their surface chemistry, as following: 1) Hydrides are present on the metallic surface and are very strongly coordinated to rhenium in agreement with rhenium molecular chemistry; 2) CO can substitute hydrides and is also strongly coordinated to the surface of Re but can react further to be substituted, oxidized or dissociated, where the latter is easier on alloy type Re-based bimetallic nanoparticles. 3) Oxidation of pure rhenium and alloy bimetallic ruthenium-rhenium nanoparticles display a zero state core and an oxide shell while core-shell type bimetallic nanoparticles result in amorphous structure. The originality of this work lies on the development of a systematic approach for the preparation of rhenium-based nanoparticles for the first time in the team and in the literature, by applying the organometallic approach largely experienced in the group for other metal systems. This method is well-known as an efficient way to obtain well-controlled nanostructures with clean surfaces, important mainly in catalysis
Pfeifer, Viktor. „Tritium and Deuterium Labelling of Bioactive Molecules Catalyzed by Metallic Nanoparticles“. Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS275/document.
Der volle Inhalt der QuelleThis PhD thesis deals with the development of new efficient methods for the incorporation of hydrogen isotopes into organic molecules, which represents a serious issue especially for drug discovery and drug development processes. After giving an introduction about hydrogen isotopes and their applications in organic molecules, the course will proceed to an overview of different chemical transformations for establishing deuterium or tritium labels on molecular frameworks. The possibilities to label N-heterocycles by hydrogen isotopes through hydrogen isotope exchange (HIE) are still very restricted and even impossible for some representatives despite the strong recurrence of these substructures in numerous biologically active molecules. For this reason, the emphasis of the practical part will lie on the development of new methods for the incorporation of deuterium and tritium on N-heterocycles through metal nanoparticle catalysis. In the first chapter, HIE through ruthenium nanocatalysts will be optimized and the application range will be demonstrated. In this context, DFT-based calculations allowed to explain experimental regioselectivities and to identify new keyintermediates. In terms of application, it was shown that the ruthenium-catalyzed method is useful for the synthesis of deuterium labelled internal standards for LC-MS quantifications and for the tritiation of complex molecules displaying satisfying specific activities. In the next chapter, the synthesis of new nickel nanoparticles and their potential to catalyze selective HIE on N-heterocyclic derivatives will be discussed
Asila, Victoire. „Syntheses of N-Heterocyclic carbenes-stabilized metallic nanoclusters and nanoparticles“. Electronic Thesis or Diss., Sorbonne université, 2022. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2022SORUS087.pdf.
Der volle Inhalt der QuelleIn this work we developed a new synthesis of phosphine and N-heterocyclic carbenes (NHCs)-stabilized gold nanoclusters (AuNCs) through the reduction of AuClPPh3 by NaBH4 in the presence of imidazolium salts as NHC precursors. The samples were characterized by various techniques, especially electrospray ionization mass spectrometry (ESI-MS). Most of the nanoclusters which were obtained are stabilized by PPh3. However, a very stable Au11(PPh3)7(NHC)Br2+ nanocluster was synthesized. The follow-up of the aging of the samples by ESI-MS showed the evolution of the composition of the suspensions over time. Less stable nanocluster structures did not remain in suspension with aging. Then, a second synthesis was performed by reduction of HAuCl4.3H2O by NaBH4 in the presence of imidazolium salts as NHC precursors and NaH as base. Gold nanoclusters stabilized by NHCs were obtained with different gold nuclearities. A strong effect of the NHC ligand on the nature of the obtained nanoclusters was revealed. Synthesis with the imidazolium salt 1,3-didodecylimidazoliumbromide (C12-Br) allowed the formation of very stable [Au13(C12)9Br3]2+ nanocluster. Finally, the synthesis of Ag2S nanoparticles stabilized by water-soluble NHCs has been reported. A silver-NHC complex was synthesized and then placed in the presence of an S2- source. The synthesis by microwave heating gave promising results since Ag2S nanoparticles emitting in the second infrared window was demonstrated. Indeed, this is the window of transparency of biological tissues which is of interest for biological applications
Manai, Ghada. „Auto-assemblage des nanoparticules métalliques orienté par des polymères peptidiques“. Thesis, Toulouse, INSA, 2020. http://www.theses.fr/2020ISAT0007.
Der volle Inhalt der QuelleHybrid organic-inorganic nanomaterials (nanocomposites) are of growing interest due to the development of new synthesis. In order to modulate their properties, it is important to control the nature of the constituents and their interactions. Within the framework of this PhD thesis, we developed a new approach to prepare nanocomposites from metallic nanoparticles (Pt, Ir, Au, etc.) using peptidic polymers (polypeptides). Polypeptides are made up of amino acids and adopt biomimetic structures (α-helix or β-sheets) as do proteins. As macromolecular ligands, they have been understudied in nanocomposite design.This research work first describes how we have prepared a library of polypeptides incorporating tailored side chain moieties modulating the binding with metallic nanoparticles. Indeed, we have fully developed an efficient 2 steps grafting process to introduce onto poly(γ-benzyl-L-glutamate) (PBLG) backbones amines promoting specific coordination binding with transition metals.The second part of the PhD manuscript describes how these polypeptides can be used to promote the in-situ synthesis of metallic nanoparticles. A comprehensive study of this approach have shown that polypeptides give access to hyperbranched nanoparticles, resulting from the coalescence of ultra-small nanocrystals, whose morphology can be controlled by modulating the properties of the polymer (polymerization degree, side chain stoechiometry).Finaly, a third part of the PhD presents how peptidic polymers can direct the self-assembly of preformed metallic nanoparticles. Using specific formulations, we obtained two-dimensional lamellar structures, whose stability is ensured by specific coordination bonding between the functional groups of the polymer and the surface of the nanoparticles. By varying the molar mass of the polymers, it was possible to control the space between the lamellae, a key structural feature that allows the electrical properties of the nanocomposites to be changed
Ibrahim, Mahmoud. „Rhodium based mono-and bi-metallic nanoparticles : synthesis, characterization and application in catalysis“. Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30063/document.
Der volle Inhalt der QuelleIn this thesis, synthesis, characterization and catalytic applications of mono- and bi-metallic rhodium-based nanoparticles are reported. Rhodium has been chosen as a primary metal given its high interest in catalysis, mainly in hydrogenation and hydroformylation reactions. The synthesis of mono-metallic rhodium nanoparticles (NPs) is the core of this work. It was performed by decomposition of the organometallic complex [Rh(C3H5)3] in solution under dihydrogen pressure and in the presence of different stabilizers including ligands and polymers to control the growth of the particles. Selected nanoparticles were deposited on the surface of amino-functionalized magnetic silica as a support for recovery and recycling concerns in catalysis. Diverse bi-metallic nanoparticles have been also prepared in one-pot conditions by co-decomposition of the [Rh(C3H5)3] with other organometallic precursors including [Ni(cod)2], [Ru(cod)(cot)], [Pt(nor)3] and [Pd(dba)2]2. Tuning of the metal ratios between [Rh] and the second metal [M], or of the nature and the amount of the stabilizer used for the synthesis allowed to obtain nanoparticles of different sizes and chemical compositions. The characterization of the obtained nanoparticles was performed by using a combination of state-of-art techniques (TEM, HRTEM, STEM-EDX, ICP, WAXS, EXAFS, Xanes, XPS, NMR...). Surface studies were carried out in some cases, by adsorbing CO on the surface of the particles which was followed by spectroscopic techniques (FT-IR, NMR) to probe their surface state. Some of these nanoparticles were investigated in catalytic reactions, mainly hydrogenation with Rh NPs and hydrogenolysis for RhNiOx NPs. Both colloidal and supported catalytic studies were carried out in the case of hydrogenation catalysis. The originality of this work lies in the development of simple synthesis tools inspired from organometallic chemistry to get well-controlled rhodium-based nanoparticles in terms of size, size distribution, composition and surface state, all these parameters being important whatever the target application. The interest of the obtained nanoparticles in catalysis has been also evidenced in different reactions. This PhD work may open new opportunities of research both in nanochemistry and catalysis
Wang, Huan. „Modeling of the plasmon resonance of metallic nanopaticles embedded in liquid crystal“. Thesis, Troyes, 2014. http://www.theses.fr/2014TROY0004/document.
Der volle Inhalt der QuelleMetal nanoparticles have unique optical properties, the control and optimization have a growing interest in fundamental research as same as applied research. A spectacular property of these nanoparticles is the localized surface plasmon resonance ( LSPR ), which is a consequence of the oscillations of free electrons at the interface between metal and dielectric.The spectral position of the plasmon resonance is largely dependent on the geometry of the nanoparticles, but also on the dielectric properties of the surrounding medium. It implies that the variation of the index of the medium surrounding the metallic nanostructures can control the LSPR resonance. Nematic liquid crystals are a great way to modify and control the plasmon resonance. Indeed, rotation of the liquid crystal molecules can induce a change in refractive index which results in a change in the optical response of the nanostructures. The aim of the thesis is to simulate arrays of gold nanoparticles in a nematic liquid crystal in order to predict the influence of the orientation of the LC molcules on the optical properties of these nanostructures. Numerical method we used is based on the finite difference time domain ( FDTD ) method. We have considered anchoring effects of molecules at the interfaces between the cell containing the liquid crystal and the substrates. And the results are compared with the case of uniform orientation of the LC molecules in the cell. The possibility of having double resonances was studied as well as the Surface Enhanced Raman Scattering (SERS ) gain associated with these specific structures
Lahouari, Adam. „Use of reactive force fields for the simulation of metallic nanoparticles“. Electronic Thesis or Diss., Sorbonne université, 2024. http://www.theses.fr/2024SORUS223.
Der volle Inhalt der QuelleNanoparticles (NPs) have become a cornerstone of nanotechnology due to their distinctive physical, chemical, and biological properties. Often composed of transition metals, they range from groups of two to thousands of atoms. This thesis explores the simulation of these nanoparticles, focusing on gold, silver, and copper, which have applications such as antibacterial silver and anticancer gold. Silver ions interact with bacterial DNA and mitochondria, but high concentrations can be harmful. Thiol can stabilize this interaction by forming a dense self-assembled monolayer on the surface.Different structures have been found depending on the metal studied. For gold, there are two structures: a simple adsorption (sqrt(3x3)) and a restructured one where gold atoms place themselves between sulfur atoms. For silver, thiols can create the sqrt(7x7) structure or form a core@shell Ag2S effect. This study aims to determine if current methods can predict these restructuring and stability phenomena of the monolayers. Molecular dynamics is used to study large systems with the reactive force field ReaxFF, allowing bond breaking and formation during simulations. A software called SAM Maker was created to generate various structures, integrated into the NATOMOS package. Silver (sqrt(7x7)) and gold (sqrt(3x3)) structures were simulated with methane and butanethiolate. The AgSCH potential was used to study stability by heating from 0 to 300K, with simulations of 0.3, 1, and 3 ns. ReaxFF showed it could produce a stable butanethiolate monolayer on Ag(111), but with differences for gold and silver.Simulations revealed dense SAM assemblies on Ag(111) without alkanothiolate decomposition. No spontaneous restructuring was observed except for NPs smaller than 4 nm. Future studies should explore pre-restructured silver surfaces with thiolates and compare their binding energies.FeNNol, a Python program, was used to create more precise potentials. Collecting 300 gold structures (3 to 25 atoms) was followed by molecular dynamics to generate unique structures. In total, 15 956 structures have been created. DFT calculations with the PBE functional and Stuttgart basis provided energy and force references for the potential. A pre-training with ReaxFF stabilized gold surfaces. Nanoparticles of 2 nm and 4 nm provided 20,000 reference structures. Adjustments refined the model with DFT references, ensuring accurate cluster descriptions.The final model was tested on the Au20 cluster, showing good agreement with DFT for dissociation energies. Cluster distances and energies were verified, confirming the model's accuracy. Another more precise model was created for systems with less than 220 gold atoms, predicting cluster energy and distances. In conclusion, this thesis demonstrated the effectiveness of ReaxFF-based simulations in predicting the stability of self-assembled monolayers on silver. Using learning algorithms created more accurate potentials for gold, leading to more reliable and detailed simulations. These advances contribute to a better understanding of nanoscale interactions and offer promising prospects for future nanoparticle applications
Vitoux, Pauline. „Élaboration de nanocomposites "nanoparticules métalliques / polymère" en milieux fluides supercritiques“. Phd thesis, Université Sciences et Technologies - Bordeaux I, 2008. http://tel.archives-ouvertes.fr/tel-00627637.
Der volle Inhalt der QuellePoupart, Romain. „Nanoparticules métalliques@polymères poreux : matériaux hybrides innovants pour la catalyse supportée“. Thesis, Paris Est, 2017. http://www.theses.fr/2017PESC1174/document.
Der volle Inhalt der QuellePorous materials based on polymers have been the subject of intense and various researches since their discovery until now. Their unique and remarkable properties, like their easy functionalization or their large porosity range reachable for instance, coupled with their low production cost makes them attractive for numerous applications. Among them, supported catalysis is booming, especially since the rising of nanoparticles. During this Ph.D. contribution, we have developed different polymeric materials, which could be used as support, focusing mainly onto three types: bulky materials, porous polymeric matrixes into capillaries and porous polystyrene arising from the selective degradation of diblocks copolymers.Firstly, different strategies have been employed for the immobilization and the generation of nanoparticles onto bulk materials. On the one hand, the synthesis of a monomer, bearing a disulphide bridge which can, after a reduction step, free a thiol moiety allowing us to anchor gold nanoparticles. On the other hand, a new route to reduce nanoparticle has been employed using gaseous hydrogen. In another part, the syntheses of different polymeric matrixes into capillaries have been made. First, we used an already known matrix, based on N-acryloxysuccinimide -after modification step via thiol-ene reaction and nucleophilic substitution by amines- to anchor copper or gold nanoparticles, respectively. Also, a new matrix based on cyclic carbonates has been used, after modification, to immobilized platinum nanoparticles. Finally, starting from diblocks copolymers possessing different junctions between both blocks (disulphide bridge or acetal), porous polystyrenes have been obtained. The copolymers bearing an acetal have been implemented to immobilized gold nanoparticles, catalysing several reactions like nitro reduction, boronic homocoupling as well as the cascade reaction of both
Triboulet, Sarah. „Etude des effets de deux types de nanoparticules métalliques sur des macrophages murins par une approche protéomique“. Thesis, Grenoble, 2013. http://www.theses.fr/2013GRENV021/document.
Der volle Inhalt der QuelleMetallic nanoparticles (NPs) are more and more widely used, from industrial processes to biomedical research.However, data on their potential toxicity towards organisms are still lacking, especially regarding molecularmechanisms. It has been proven that some inorganic particles can lead to diseases when tissues are chronicallyexposed. In the case of pulmonary silicosis and asbestosis, induced by silica particles and asbestos fibers, chronicinflammation through alveolar macrophages is responsible for the disease. Indeed, macrophages are the firstdefense against exogenous attacks, like pathogens or inorganic compounds, which are eliminated throughphagocytosis and inflammatory processes that are part of the innate immune response. Thus, this study aimedat analyzing the molecular effects of both copper- and zinc-based NPs (Cu/CuO and ZnO) on murinemacrophages cell lines. To this end, a reproducible proteomic-based approach using 2D electrophoresis andmass spectrometry was used. The proteomic data were validated using targeted approaches on both cell linesand primary macrophages. Our results show that both NPs exert similar high cytotoxicity, but the molecularresponses are markedly different. Copper-based NPs strongly induce oxidative stress as well as alterations inmitochondrial metabolism, phagocytosis, and inflammatory mediators’ production. These effects seem to bemostly related to the redox properties of copper, and are specific to the NP form. Conversely, zinc inducedlimited effects on the same processes, thus leading to no significant alterations in macrophages’ immunefunctions. These effects are not NP-specific, since Zn2+ ions seem to exert most of them, probably due to theirability to interact with numbers of proteins, slightly altering their normal functions, and eventually leading onlyto cell death without prior functional alterations. This study allowed us to highlight some molecular mechanismsof both NP’s toxicity
Martinez, Marrades Ariadna. „3D microscopy by holographic localization of Brownian metallic nanoparticles“. Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066018/document.
Der volle Inhalt der QuelleIn this thesis work, we present a novel stochastic microscopy technique based on Digital Holography for the 3D mapping of optical intensity distributions. We show that this far-field, wide-field, 3D microscopy can be turned into both a superresolution and a near-field imaging technique. To do so, we use metallic nanoparticles undergoing Brownian motion as stochastic local field probes that we localize in three-dimensions in order to overcome the diffraction limit. The random motion of the particles allows for a complete exploration of the sample. Beyond simple localization, the gold markers can actually be envisaged as extremely local electromagnetic field probes, able to scatter light into the far-field. The technique we propose here is therefore a combination of the concepts of superlocalization and NSOM microscopies. The possibilities of the technique are illustrated through the 3D optical mapping of an evanescent and a propagative wave. Fast computation methods allow us to localize hundreds of particles per minute with accuracies as good as 3×3×10 nm3 for immobilized particles. In addition to optical intensity mapping, we show a particular application in electrochemistry, by coupling our high resolution images with electrochemical oxidation measurements on silver nanoparticles in solution at the vicinity of an electrode. Our results pave the way for a new subwavelength imaging technique, well adapted to optical characterization in water-based systems (such as in emerging microfluidics studies), which are mostly inaccessible to electron microscopy or local probe microscopies
Ngema, Xolani Terrance. „Nanoparticules métalliques enrobées de polymère : une plateforme multifonctionnelle pour application aux biocapteurs électrochimiques“. Thesis, Cergy-Pontoise, 2018. http://www.theses.fr/2018CERG0983/document.
Der volle Inhalt der QuelleTuberculosis (TB) is an airborne disease caused by Mycobacterium tuberculosis (MTB) that usually affects the lungs leading to severe coughing, fever and chest pains. In 2015 it was estimated that over 9.6 million people worldwide developed TB and 1.5 million died from the infectious disease of which 12 % were co-infected with human immunodeficiency virus (HIV). In 2016 the statistics increased to a total of 1.7 million people died from TB with an estimated 10.4 million new cases of TB diagnosed worldwide. The development of the fast and reliable point-of-care systems that are ultra-sensitive, cheap and readily available is essential in order to address and control the spread of the tuberculosis (TB) disease and multidrug-resistant tuberculosis. This work is the feasibly study on one part on the development of electrochemical immunosensor using a specific Mycobacterium tuberculosis Ag85B antigen to detect tuberculosis and on another part on the development of biosensors using cytochrome P450-2E1 (CYP2E1) enzyme to detect anti-TB drugs in aqueous systems. The immunosensor was developed by adopting the indirect ELISA method which was used for the detection of the IgG antibodies using the tuberculosis IgG ELISA. The development of immunosensor was achieved using glassy carbon electrode (GCE) modified with polyamic acid (PAA) in which Mycobacterium tuberculosis recombinant antigen Ag85B (Ag) was immobilized. PAA was electrodeposited on glassy carbon electrode (GCE) using cyclic voltammetry. The modified electrodes were characterized by cyclic and square wave voltammetry. The response profile of the immunosensor at Mycobacterium tuberculosis antibodies was studied by square wave voltammetry and the linear response was in a range of 0.3 to 1.6 mg/mL with a detection limit (LOD) of 0.08 mg/mL. On the other hand, two platforms for the development of biosensors for the detection of ethambutol and rifampicin (anti-TB drugs) were also prepared. Two platforms were prepared whereby polyamic acid-silver nanoparticles composite (PAA/AgNPs) was drop-coated on GCE to form GCE/PAA/AgNPs platform. While the other platform (GCE/PPy/AgNPs) was formed by electrodeposition of polypyrrole-silver nanoparticles composite (PPy/AgNPs) on GCE using chronopotentiometry. The GCE/PAA/AgNPs and GCE/PPy/AgNPs platforms were then characterized using cyclic voltammetry while their morphologies were obtained by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The immobilization of cytochrome P450-2E1 enzyme (CYP2E1) on both platforms was achieved by means of drop coating. The efficiency of the GCE/PAA/AgNPs/CYP2E1 and GCE/PPy/AgNPs/CYP2E1 biosensors for the detection of ethambutol (ETH) and rifampicin (RIF) was studied by differential pulse voltammetry (DPV). The GCE/PPy/AgNPs/CYP2E1 biosensor was able to detect anti-TB drugs at their peak serum levels (2 – 6 µg/mL). Whereas the GCE/PAA/AgNPs/CYP2E1 biosensor was able to detect ethambutol at concentrations lower than the serum level (2.5 ng/mL to 12.5 ng/mL). Therefore, GCE/PAA/AgNPs/CYP2E1 biosensor has an ability to detect ethambutol even at trace levels in aqueous systems. Thus, the GCE/PAA/AgNPs/CYP2E1 biosensor have lower limit of detecting ETH (0.75 ng/mL) than GCE/PPy/AgNPs/CYP2E1 biosensor (1.3 µg/mL). The sensitivity of GCE/PAA/AgNPs/CYP2E1 biosensor for ETH was 5 μA/ng.mL-1while the sensitivity of GCE/PPy/AgNPs/CYP2E1 biosensor was 2.6 μA/μg.mL-1. The GCE/PPy/AgNPs/CYP2E1 biosensor was the only biosensor that was able to detect RIF with a limit of detection of 7.5 µg/mL. The GCE/PPy/AgNPs/CYP2E1 biosensor is suitable for the detection of ETH and RIF at serum levels and aqueous systems. While the GCE/PAA/AgNPs/CYP2E1 is suitable for only detecting anti-TB drugs at trace levels in water
Liakakos, Nikolaos. „Organometallic approach to the growth of metallic magnetic nanoparticles in solution and on substrates“. Thesis, Toulouse, INSA, 2013. http://www.theses.fr/2013ISAT0026/document.
Der volle Inhalt der QuelleThis thesis concerns a new wet chemical seeded growth method that can produce arrays of metal nanostructures epitaxially grown on crystalline macroscopic surfaces which act as seeds. This approach produces wafer-scale organized 2D hexagonal arrays of perpendicularly oriented, monodisperse and monocrystalline metallic Co nanowires with diameters below 10 nm which exhibit perpendicular magnetic anisotropy and are interesting for applications in ultra high density magnetic recording. Extension of this approach to iron gives rise to nanostructured iron films. The orientation of the nanostructures on the solid substrate depends on the substrate crystallographic orientation, whereas their morphology is dictated by the solution composition. This objective was attained through parallel studies on the growth mechanism of cobalt nano-crystals in solution which revealed an unexpected influence of the stock solution preparation procedure on the nanocrystal morphology. In addition, the use of nanoscopicseeds for the overgrowth of cobalt and iron gave rise to long Co nanowires and Co-Fe dumbbells and contributed to the definition and the improvement of the experimental conditions for the seeded growth of Co and Fe on the solid substrates
Liu, Zeming. „Self-organization of metallic nanoparticles in waveguides by laser : mechanisms modelling and new approaches“. Thesis, Lyon, 2016. http://www.theses.fr/2016LYSES073/document.
Der volle Inhalt der QuelleThis doctoral thesis focuses on the study of laser-induced self-organization of Ag nanoparticles (NPs) in TiO2 thin layers. This laser technique was recently developed to provide original printing solutions for applications like active color displays, security, or polarization imaging. Here, we investigate experimentally and theoretically the different mechanisms involved in the NPs formation for a better control of their morphology and organization. In the case of continuous-wave (cw) laser, our experimental results prove that the speed at which the laser scans the sample surface is a crucial parameter to control the NP size and the laser-induced temperature rise. Ag NPs shrink at low scan speed, whereas growth governed by a thermal effect only occurs above a speed threshold. Above this threshold, the size of grown Ag NPs changes in a non-monotonous way with scan speed, whereas laser-induced temperature rise increases with speed. In order to explain these counter-intuitive behaviors, several numerical models have been developed to simulate changes in the size distribution of Ag NPs induced by visible light. Simulation results are in good agreement with experimental observations and reveal the origin of the observed phenomena by collective interactions of various physico-chemical processes involved in the variation of NPs size. Finally, this thesis demonstrates that self-organization of NPs at sub-wavelength scale on large areas can also be performed with femtosecond (fs) laser pulses. Oriented anisotropic growth of NPs has also been observed using a proper selection of laser irradiation parameters. Compared with the cw laser induced structures, fs pulses offer better control of the thermal effect and NP size, which opens the way to transfer these technologies on plastic or paper substrates
Erbi', Matteo. „Impact of Mechanical Loading on the Deformation and the Electronic Properties of Metallic Nanoparticles“. Electronic Thesis or Diss., Sorbonne université, 2023. http://www.theses.fr/2023SORUS620.
Der volle Inhalt der QuelleMetallic nanoparticles (NPs) are fascinating objects, possessing unique properties that differ significantly from their bulk counterparts due to their high surface area-to-volume ratio. As a result, many nanoparticle-based technological approaches are being foreseen across fields such as catalysis, medicine, and optic applications. However, regardless of their application domain, NPs can be subjected to mechanical constraints, potentially leading to structural modifications or even irreversible changes that drastically impact their intended use. In this thesis, we explore the influence of some tunable characteristics of NPs (shape, size, and composition) on their mechanical properties and investigate how plastic and elastic deformations affect their absorption properties. Our goal is to highlight a viable path to develop a new class of nano-objects. By combining molecular dynamics with finite element calculations, we present an extensive study on the elastic and plastic deformations of metallic (Au, Cu, and Pt) nanoparticles of different shapes and sizes. We impose mechanical loading through nano-indentation on (001) and (111) facets. In the elastic regime, there is no size effect for nanoparticles larger than 5 nm. Conversely, the elastic properties of NPs are highly driven by the shape of the particle: a clear shape effect emerges from our results. For a given imposed deformation, the distribution of the stress field in the NP is heterogeneous and depends strongly on the shape of the NP, having a major impact on elastic properties such as the NP's effective Young’s modulus. The focus then shifts to the plastic transition, by examining by analyzing the critical stress required for dislocation nucleation and understand how the shape and size of nanoparticles affect this key parameter. Our study shows that both the size and shape of the NPs influence the critical stress. By adjusting NP morphology, we can tune the onset of plasticity. A universal effect of size and shape on dislocation nucleation is identified for FCC metals, complementing existing literature results for specific NP shapes. Furthermore, our analysis highlights that NP corners are stress hotspot regions where dislocation nucleation primarily occurs. We develop a simple model based on FE calculations, indicating that dislocation nucleates when a specific Von Mises stress value is reached near NP corners. The research further looks into different mixing patterns of copper-gold nano-alloy. Ordered and disordered systems are tested, showing that the elastic and plastic behavior is sensitive to the mixing pattern. Ordered structures can exhibit strengthening compared to pure Gold or Copper NPs, while solid solutions show a softening, unlike bulk material. Our findings indicate that local order influences the elastic and plastic behaviors of alloy NPs. Knowledge gained in the field of mechanical deformation of nanoparticles is exploited to study changes in their electronic properties. For this purpose, a costume tool is developed based on the tight-binding formalism to compute the effects of both elastic and plastic deformation on the electronic properties of indented Pt NPs. Our results emphasize that, unlike elastic deformation, plastic deformation introduces new, low coordinated surface sites that can enhance NP surface reactivity. The enhanced surface reactivity of these new sites is confirmed by DFT calculations examining Hydrogen absorption on plastically deformed Pt NPs
Veron, Olivier. „Etude des mécanismes de coloration de verres obtenue par échange ionique Ag+/Na+ et précipitation de nano agrégats métalliques“. Phd thesis, Université d'Orléans, 2010. http://tel.archives-ouvertes.fr/tel-00617160.
Der volle Inhalt der QuelleHallot, Gauthier. „Synthèse, caractérisations et vectorisation des nanoparticules de bismuth métallique pour des applications théranostiques“. Thesis, Sorbonne université, 2019. https://accesdistant.sorbonne-universite.fr/login?url=http://theses-intra.upmc.fr/modules/resources/download/theses/2019SORUS272.pdf.
Der volle Inhalt der QuelleMetallic bismuth nanoparticles are poorly described in the literature and yet they have a high medical potential. Their utility is particularly described in therapeutic and/or diagnostic applications. In addition, bismuth is an abundant, inexpensive and biocompatible element. In this project, a robust and reproducible synthesis of metallic bismuth nanoparticles in water in a non-continuous process was developed by applying the principles of green nanochemistry. This synthesis was then transferred to a continuous process to increase the productivity of obtaining nanoparticles. The characterization of their surface, chemical and colloidal stability as well as their cytotoxicity were studied in order to consider their use in biological environments. Three types of hydrophilic, hydrophobic and fluorophilic nanoparticles have been obtained. Hydrophilic nanoparticles with polyethylene glycol on their surface are stable for 24 hours in saline solution. Hydrophobic nanoparticles have been incorporated into oil-in-water emulsions. On the other hand, polyfluorinated nanoparticles containing insufficient fluorine on the coating agent could not be incorporated into a fluorinated oil. Finally, a preliminary study did not show a radiosensitization effect of bismuth nanoparticles. In vitro and in vivo studies of these nanoparticles are planned to definitively conclude on their radiosensitizing effect
Palussière, Ségolène. „De la synthèse de nanoparticules de CuO par voie organométallique à l'assemblage de matériaux énergétiques Al/CuO“. Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30269.
Der volle Inhalt der QuelleAmong the energetic materials, nanothermites are known for their high reactivity and their use in pyrotechnic applications. In this context, the Al/CuO composite is a promising material for integration into micro-devices, due to its high enthalpy of oxidation-reduction reaction. The increase of the contact surface between the two reactants of the thermite improves the properties. Control of the size, morphology and distribution of nanoparticles within the nanocomposite is therefore of fundamental importance. In the majority of cases, the nanothermites are obtained by physical mixing of non-dispersible commercial nanopowders. In this thesis we proposed to explore an organometallic way to synthesize CuO nanoparticles to assembly with Al commercial nanoparticles. For this purpose, CuO nanoparticles are synthesized by hydrolysis or controlled oxidation of an organometallic precursor (copper amidinate) in the presence of organic ligands (octylamine). Sizes, shapes and distributions vary depending on the experimental conditions of the syntheses. The surface states of the CuO nanoparticles were then analyzed by NMR and infrared spectroscopy characterization methods. The information acquired allowed us to identify the interactions between the ligands and the surface of the nanoparticles. In a second step, the CuO nanoparticles are mixed by ultrasons with nanopowders dispersed in an organic solvent. The thermal characterizations of these nanocomposites show the presence of non-characteristic exothermic and endothermic reactions of the usual Al + CuO thermite reaction. Thermal and structural analyzes of CuO nanoparticles revealed that the ligands oxidize at low temperature (~ 200 °C) and reduce the CuO to Cu2O then to metallic Cu, before the thermite reaction takes place. An optimized experimental protocol was finally implemented to preserve the structure of CuO while eliminating the ligands present in the stabilizing layer of the nanoparticles. These new assemblies generate a reaction energy equivalent to Al/CuO nanothermites obtained by mixing commercial powders. But these nanocomposites have lower initiation temperatures, which is interesting for some applications. The accumulated knowledge of surface states and the stabilization of nanoparticles in solution open the way to the integration of nanocomposites on microelectronic chips by “inkjet” technology
Lee, Suyeon. „Synthesis and properties of mono and bi- metallic nanoparticles of noble metals; towards fabrication of novel functional nanoparticles assemblies“. Electronic Thesis or Diss., Sorbonne université, 2021. http://www.theses.fr/2021SORUS580.
Der volle Inhalt der QuelleNoble metal nanoparticles (NPs) have attracted a great interest last years in various domains due to their distinct physical and chemical properties such as optical, catalytic or magnetic properties. In this thesis, we investigated the various approaches to integrate two metals in the same system, such as bimetallic nanoparticles, or binary superlattices to obtain new properties. We have developed seed-mediated growth method to rationally synthesis core-shell NPs Au(or Ag)@M (M=Ag, Pd, Pt). The impact of synthesis parameters such as concentration of metallic precursors, nature of ligands or temperature on key NPs parameters (core size, shell thickness, dispersity) was studied. The optical, vibrational and catalytic properties of different bimetallic NPs were characterized according to their structure, chemical composition, number of shell atomic layer and core crystallinities. In addition, binary NP superlattices, which are co-assembled from of two different complementary components were also reported. Several assembly conditions (effective size ratio, concentration ratio, deposition temperature, deposition method) were explored. The physical mechanism responsible for the observed structural variation was thus identified. A variety of crystalline structures for the binary superlattices such as AlB2, NaZn13, NaCl were produced. Finally, the magnetic properties of Fe2O3/Au NP binary superlattices were studied. They are determined by the interparticle distance of Fe2O3 NPs modulated by the insertion of Au NPs
Nadar, Latifa. „Surfaces fonctionnalisées à base de nanoparticules métalliques pour l'optique et la photonique“. Phd thesis, Université Jean Monnet - Saint-Etienne, 2011. http://tel.archives-ouvertes.fr/tel-00700483.
Der volle Inhalt der QuelleMehedi, Hasan-Al. „Diamond nanostructure fabrication by etching and growth with metallic nanoparticles“. Thesis, Grenoble, 2012. http://www.theses.fr/2012GRENT107/document.
Der volle Inhalt der QuelleOne-dimensional structures with nanometre diameters, such as nanotubes and nanowires, have attracted extensive interest in recent years and form new family of materials that have characteristic of low weight with sometimes exceptional mechanical, electrical and thermal properties. Without any change in chemical composition, fundamental properties of bulk materials can be enhanced at the nanometre scale leading to extraordinary nanodevices.Since a few years, nanowires of different semiconducting materials have been grown. To mention few of these, Si, GaN, SnO, SiC and ZnO nanowires were all successfully demonstrated. However, the growth of diamond nanowires has not yet been demonstrated, despite the strong interest for this material. Bulk diamond combines various exceptional properties for a wide range of applications: Chemical inertness, radiation hardness, biocompatibility, high hole/electron mobility (2000/1000 cm2/V/s), high thermal conductivity (22 W/cm/K), wide bandgap (5.5 eV), and wide electric potential window (3.25 eV H-O evolutions).Since about 30 years, the growth of diamond thin film is well controlled either as insulator or as semiconductor with p- and n- type dopants. Fabrication of 25x25 mm2 monocrystalline diamond wafer has already been reported, and two inches wafers are expected in a couple of years demonstrating the growing interest for this material. Among present or short-term applications one can mention alpha-particle detectors, solar-blind UV sensors, high voltage electronic devices, bio-sensors and single photon source. The realization of nanowires should improve the performance of some of these devices and also open a range of new high performance applications.The stability of 0D (nanocrystals) and 1D (nanowires) diamond nanostructures has been extensively studied using ab initio modelling and indicates that for specific crystallographic orientations clusters of nanometric size are thermodynamically stable. One experimental indication for diamond nanowire growth has been published by Sun et al. in 2005, based on nanocrystal nucleation and growth on carbon nanotubes followed by 1D growth. This particular nucleation process on carbon nanotube has furthermore been explained theoretically in 2009.Based on these experimental and theoretical results, the first objective of this thesis was to explore the growth of diamond nanowire and find suitable conditions to obtain nanowires in a reproducible way. A wide range of process conditions were explored, first without any catalyst, then with metallic catalyst in order to promote Vapour-Liquid-Solid (VLS) growth. Although a comprehensive knowledge regarding carbon nanotube stability in hydrogen atmosphere and diamond-catalyst interaction has been obtained and some carbon nanostuctures were grown, no diamond nanowires were obtained in a reproducible way.However, the careful study of the diamond-catalyst interaction revealed a very interesting etching process that could be very useful for the fabrication of diamond nanostructures. A second objective was then defined: development of the etching process for diamond using transition metal as catalyst and optimization of the process parameters for specific applications such as the fabrication of porous diamond membranes for bio-sensors
Astudillo, Neira Catalina Andrea. „Nanoparticules d'oxyde de nickel et de cobalt incorporées dans des films de polypyrrole en tant que matériau électrocatalytique efficace pour l'oxydation de l'eau“. Thesis, Université Grenoble Alpes, 2020. https://thares.univ-grenoble-alpes.fr/2020GRALV016.pdf.
Der volle Inhalt der QuelleThis thesis deals with the development of highly active and stable anodes for electrocatalytic water oxidation under near-neutral pH conditions, based on nickel or cobalt or nickel/iron oxide nanoparticules embedded into a poly(pyrrole-alkylammonium) matrix. Prepared by an all-electrochemical procedure, these nanocomposite materials are highly nanostructured with sizes of metal oxide particle between 20 and 30 nm, which are well dispersed into the polypyrrole film, conferring a great electroactive surface area and thus a high electrocatalytic activity towards water oxidation at near neutral pH of 9.2. These performances place these nanocomposite based electrodes among the most active anodes described in the literature employing either nickel or cobalt or nickel/iron oxide at pH 9.2. In addition, when the nanocomposite material is electrodeposited on porous ITO, the physisorption of the nanocomposite film is considerably enhanced and consequently its catalytic activity is very stable beyond 24 h of electrolysis. This work demonstrates the beneficial role of positively charged polypyrrole matrix in the preparation of small particles of metal oxide and in the achievement of highly stable and active anodes for water oxidation
Mika, Arkadiusz. „Interactions of slow multiply charged ions with large, free radiosensitizing metallic nanoparticles“. Thesis, Normandie, 2017. http://www.theses.fr/2017NORMC263/document.
Der volle Inhalt der QuelleThis thesis presents a study of the interaction of multiply charged ions with metallic nano-sized particles both in the context of fundamental processes and possible applications as radiosensitizers in nanoparticle-enhanced hadrontherapy. For this purpose a new experimental set-up has been constructed based on a magnetron-discharge cluster source, a deposition chamber for analyzing the size of neutral nanoparticles with AFM and TEM techniques and a time-of-flight mass spectrometer able to detect positively charged particles with masses up to 50 000 amu. Collision studies were performed with Bi clusters of 2nm in diameter, containing 200 atoms, as well as Ag nanoparticles (6 nm, 5000 atoms). In both cases multi-electron capture leads to the formation of multiply charged systems. In the Bi case a large fraction fragments by asymmetric fission emitting small singly charged fragments. In the case of large Ag nanoparticles multiply charged systems are stable. However, small size fragments are formed due to sputtering of the nano-surface in penetrating collisions. Future experiments will be performed with functionalized metal nanoparticles, aiming to count the number of electrons emitted after ion collisions
Palazzolo, Alberto. „Development of new methods for the hydrogen isotope exchange catalyzed by metallic nanoparticles“. Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS276.
Der volle Inhalt der QuelleHydrogen isotopes labelled compounds possess a broad range of application in the early pre-clinical phases of drug development process. For instance, deuterated compounds are applied as internal standard in quantitative LC-MS techniques while tritiated molecules are often the preferred radioactive tracers for the study of molecular absorption, distribution, metabolism and excretion (ADME). After a brief introduction, a first chapter will discuss the development of a mild and selective method to perform late stage labelling of variously functionalized nucleobases and drug analogues catalyzed by ruthenium nanoparticles. By changing the ligand which stabilizes the nanocatalyst, we achieved challenging isotopic exchanges such as tritiations of pharmaceuticals using subatmospheric pressure of tritium gas and deuteration of sensible oligonucleotides. The next chapter will describe the modification of commercially available ruthenium nanocatalysts via the coordination of N-Heterocyclic carbenes (NHCs). The modification granted enhanced regio and chemoselectivity for the deuteration of aliphatic alcohols. Some of the modified ruthenium catalysts allowed the hydrogen/deuterium exchange on easily reducible compounds which were not obtainable using the unmodified commercial catalyst. The final chapter will discuss the synthesis and the evaluation of the catalytic activity of iridium nanoparticles. The latter, showed an interesting reactivity for the labelling of challenging substrates. In some of the investigated compounds, IrNps were able to introduce deuterium with unusual regioselectivities compared to already described hydrogen isotope exchange reactions
Mansour, Yehia. „Études théorique et expérimentale de la formation des nanoparticules métalliques par ablation laser en milieu liquide. Modélisations des propriétés optiques et thermiques de l'interaction Laser-Nanoparticules“. Electronic Thesis or Diss., Université de Lorraine, 2020. http://www.theses.fr/2020LORR0283.
Der volle Inhalt der QuelleNoble metal nanoparticles (NPs) are the site of a surface plasmon resonance phenomenon resulting from the collective oscillation of their conduction electrons under the effect of an electromagnetic wave. In the case of gold and silver NPs, the resonant frequency is in the visible range, which gives these plasmonic NPs unique optical properties. In particular, the position and intensity of the plasmon resonance depend on their size, shape (aspect ratio) and the index of the host medium. The possible applications require pure samples and mono-dispersed distribution. The chemical synthesis of NPs allows the shape and size of NPs to be controlled. However, it requires the use of stabilizing agents, which lead to surface contamination by synthetic residues. To limit this disadvantage, the physical technique of laser ablation in a liquid medium is a promising alternative, which, however, suffers from a lack of control over the shape and size of the NPs produced. The shape and size of NPs produced by liquid laser ablation (ALML) are closely related to the three essential steps of the process: Target / laser interaction; Mass transport; Laser / NPs interaction suspended in the liquid. In order to understand the mechanisms governing each of these stages, it is necessary to study them separately. In this work, we focused on the mechanisms of interaction between the laser beam and the NPs suspended in the liquid. Depending on the energy density absorbed by the suspended NPs, they undergo fragmentation or remodeling. We then studied the mechanisms behind the phenomenon of fragmentation. The evolution of the shape distribution of NPs during NP fragmentation was studied by developing an original and quantitative technique of in-situ optical spectroscopy. And, the evolution of the volume fraction of NPs during their preparation by ALML by in-situ optical spectroscopy is obtained and analyzed. In parallel with the experimental work, we have developed theoretical models for understanding the mechanisms of formation of metallic nanoparticles by laser ablation in a liquid medium. A modest study on the modeling of optical and thermal properties of the Laser-Nanoparticle interaction is discussed in this thesis. A modified Takami thermal model named MTM was also presented. Its important utility has been demonstrated for mechanisms for the interpretation of the mechanisms of laser-NPs interaction
Vernier, Charles. „Étude de nanocristaux métalliques anisotropes par spectroscopies optique et vibrationnelle“. Electronic Thesis or Diss., Sorbonne université, 2024. https://theses.hal.science/tel-04829448.
Der volle Inhalt der QuelleWe use both electronic microscopy and spectroscopic methods (optical and vibrationnal) to caracterize metallic nanoparticles. Nanoparticules with a narrow size dispersion were synthesized according to state of the art protocols. These nanoaprticles (silver nanocubes, gold nanorods, gold-core silver-shell nanoarods) were first caracterized by TEM and HRTEM. The optical properties of these nanoparticles were studied by UV-visible-NIR absorption spectroscopy and the parameters influencing their localized surface plasmon resonance (size, shape, composition) were studied and compared with numerical calculations by discrete dipole approximation. The broadening of the longitudinal localized surface plasmon of gold nanorods due to the aspect ratio distribution is shown. Nanoparticules also confine acoustic waves. This effect is studdied by low frequency Raman scattering. Confined acoustic waves depend on the size, the shape and most importantly on the cristallinity of the nanoparticules. Low frequency Raman spectra of nanoparticles of similar size and shape but of varying cristallinity (monocristalline gold nanorods and polycristalline gold nanorods) are completely different : the quadrupolar mode of the polycristals is split into two modes for the monocrystals. Finally, this work brings experimental data to groups who try to model low frequency Raman spectra of anisotropic nanoparticles and take into account acousto-plasmonic coupling
Mazzucco, Stefano. „Mapping localized surface plasmons at the nanometer scale in complex-shaped sub-wavelength metallic nanoparticles“. Paris 11, 2009. http://www.theses.fr/2009PA112367.
Der volle Inhalt der QuelleThis thesis presents the outcome of the study of Localised Surface Plasmons (LSPs) on silver and gold nanoparticles with Electron Energy-Loss Spectroscpy (EELS) and of the development of a cathodoluminescence (CL) detector integrated with a scanning transmission electron microscope (STEM). STEM-EELS can extend the knowledge of LSPs by overcoming the limitations of optical techniques. We showed how the shape, material and size of a nanoparticle affect dramatically the behaviour of LSPs by determining the energy and number of LSP resonances as well as whether they interact with one another or not. We also demonstrated that a STEM-CL detector can be sucessfully used to combine high spatial resolution with high energy resolution for the study of nanoparticles
Doumandji, Zahra. „Identification de marqueurs d’exposition et d’effets de nanoparticules métalliques sur modèle in vitro“. Thesis, Université de Lorraine, 2019. http://www.theses.fr/2019LORR0067.
Der volle Inhalt der QuelleAs a consequence of the extension of the use of nanoparticles in different industrial sectors, the number of potentially exposed workers continues to grow, without fully knowing the toxicological properties of these materials. Since nanoparticles can be aerosolized in the occupational atmosphere, inhalation is the major occupational exposure route. For this reason, risk assessment of exposure to nanomaterials requires toxicology studies to be conducted on cellular models of the airways. In this manuscript, the cellular and molecular responses of rat alveolar macrophages (NR8383) exposed to metallic oxide nanoparticles: ZnO, ZnFe2O4, NiZnFe2O4, Fe2O3, TiO2-NM105 and TiO2-NRCWE001, were studied, combining conventional toxicological analyzes (characterization of nanoparticles by transmission electron microscopy and dynamic light scattering, evaluation of cytotoxicity by WST-1 assays and LDH release); and high throughput molecular screening (transcriptomic and proteomic analyzes). NR8383 cells were exposed to the ZnO, ZnFe2O4, NiZnFe2O4, Fe2O3, TiO2-NM105 and TiO2-NRCWE001 nanoparticles for 24 h which allowed for the determination of a sub-toxic dose for each nanoparticle to which the macrophages were exposed for molecular analysis. Four hours after exposure NR8383 to nanoparticles, many genes and proteins were differentially expressed. Oxidative stress was the adverse biological response following exposure of cells to nanoparticles composed of zinc. In contrast, inflammation was the main activated pathway in cells exposed to the anatase and rutile form of TiO2 nanoparticles. In conclusion, this study exposes the "biological fingerprints" of the two groups of nanoparticles of interest. Finally, our study, combined with previous literature studies, could also be beneficial in validating biomarkers of exposure and effects of nanomaterials suggested in order to predict adverse biological effects
Vandenhecke, Ellick. „Nanostructuration de surfaces diélectriques par pulvérisation ionique pour guider la croissance de nanoparticules métalliques“. Thesis, Poitiers, 2014. http://www.theses.fr/2014POIT2272/document.
Der volle Inhalt der QuelleOn the one hand, the aim of this work is to understand and control the formation of periodic nanometric ripples produced by ion sputtering of dielectric thin films. On the other hand, these nanostructured surfaces are used to guide the growth and organization of silver nanoparticles. These anisotropic systems are characterized by a surface plasmon resonance whose spectral postion is dependent on the polarization of the incident light. We first study the influence of different ion beam sputtering parameters (the ions incidence angle and energy, temperature, energy, flux, fluence) on the ripple morphology (period, amplitude, order, ...) by AFM and GISAXS. The relevant parameters for the control of the ripple morphology are identified as well as some of the physical mechanisms involved. Then, we study the influence of the growth conditions on the structural properties of the nanoparticles (metal deposition angle, ripples pattern quality) by HAADF-STEM. We show that the preferential growth along the ripples is promoted by shadowing effects, thus leading to the formation of linear chains with period similar to the underlying ripples and with more or less elongated and aligned nanoparticles. This results in a far-field tunable optical anisotropy arising from polydisperse interparticle gaps (less than a few nanometers) as well as from more or less strong near-field coupling phenomena. These structures could offer potential for surface enhanced Raman spectroscopy (SERS) applications
Soulmi, Nadia. „Mise au point de nouveaux procédés d'élaboration en milieu liquide ionique de nanomatériaux à base d'étain en vue de leur utilisation comme électrode négative de batterie Li-ion“. Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066520/document.
Der volle Inhalt der QuelleTin is a promising alternative to replace graphite carbon as a negative electrode material in Li-ion batteries due to its high specific theoretical mass capacity of 993 mAh.g-1. However, change in volume during lithiation leads to its mechanical degradation during the cycling, and consequently very short life of the material. To overcome this issue, the use of the intergranular space via the nanostructuration of the material combined by the addition of a carbon matrix or other inactive element vs. lithium (intermetallic alloys), which buffers drastically the volume expansion during the lithium alloying process, is employed. The aim of this work is to develop new processes for the synthesis of tin nanoparticles and tin-copper alloys in ionic liquid medium. Sn nanoparticles varying in size from 7 to 45 nm were synthesized, according to the cation-anion combination of the ionic liquid and from different metallic salts, as well as a nano-alloy compound, Cu6Sn5. The size of the nanoparticles is directly related to the nature of the anion although the cation has a privileged interaction with the metal surface of the nanoparticles. Once isolated from the ionic liquid, Sn and Cu6Sn5 nanoparticles have a core-shell architecture with a metallic or intermetallic crystalline core and an amorphous shell of tin oxides. A reversible conversion mechanism of the SnOx from the shell is highlighted for Sn@SnOx nanoparticles, with a high specific capacity of approximately 950 mAh.g-1. Sn-Cu@SnOx nano-alloys have a capacity close to the theoretical for an alloy mechanism at more than 530 mAh.g-1
Fu, Xingjie. „Synergy between photoswitchable fluorescent proteins and metallic nanoparticles : a combination of theoretical and experimental studies at ensemble and single particle level“. Electronic Thesis or Diss., Université de Lille (2022-....), 2023. https://pepite-depot.univ-lille.fr/ToutIDP/EDSMRE/2023/2023ULILR070.pdf.
Der volle Inhalt der QuelleReversibly switchable fluorescent proteins (RSFP), characterized by a photo-switching from a non-fluorescent (Off) to a fluorescent (On) state, are valuable tools to a variety of applications in biological imaging especially in super-resolved fluorescence microscopies. The photochromic and photophysical properties of RSFPs such as molar extinction coefficients, fluorescence quantum yield, thermal back recovery and photo-switching quantum yield are essential as they impose the switching contrast and theoretical maximum resolution, and they are also linked to the brightness, contrast of images and imaging acquisition speed in these microscopies. In this thesis we focus on rsEGFP2 which is a peculiar RSFP used in the reversible saturable optical fluorescence transition (RESOLFT) method, a super-resolved microscopy technique that allows significant reduction in the illumination intensities and in photobleaching. While targeted or random mutation is the general technique to modulate properties of RSFPs, this thesis is demonstrating that using plasmonic effect and enhancement of electromagnetic field of specific metal nanoparticles, it is possible to change and optimize the photophysical properties of rsEGFP2. In literature, there is a large discrepancy about fluorescence and switching quantum yield values of rsEGFP2. In addition, these values are usually given at room temperature, which are different from the temperature setting for in-vivo studies. Therefore, we firstly determined the temperature-dependence of fluorescence and switching quantum yield temperature-dependence for rsEGFP2. For the switching quantum yield we developed a new budget-friendly experiment to follow the evolution of absorbance at different temperature under continuous irradiation. Taking into account for the first time the full set of influencing parameters, i.e., dependence of switching yield on irradiation wavelengths, influence of the thermal back recovery rate constants, the extinction coefficient of all absorbing species, and with an evaluation of robustness and error propagation, we determined On-to-Off and Off-to-On switching quantum yield values under specific temperatures. We found that at 37° the thermal recovery has a strong impact on the determination of the quantum yield values. Moreover, the photo-switching quantum yields in both On-to-Off and Off-to-On directions is dependent on irradiation wavelength and on temperature dependent with varied degrees, while the fluorescence quantum yield decrease about 30% in comparison to room temperature. Therefore, we propose a new photodynamics scheme with two different On-state ground state species, i.e., a non-emissive one that controls the On-to-Off switching and an emissive one the brightness. Then, we calculated the size and shape dependence of the plasmonic properties of gold and silver nanoparticles to find the good candidate for modulating fluorescence and switching quantum yield. The key factor behind the different outcomes by plasmonic nanoparticles lies in their different scattering and absorption properties. Based on the simulation, we synthesized 100 nm diameter silver nanoparticle and gold nanorods. The silver nanoparticle has a SPR band at 450 nm while it is at 540 nm for the gold ones. Preliminary studies of these nanoparticle alone or embedded within a polymer (PVA) containing rsEGFP2 were performed. Using a FLIM microscope, we measured the intensity time traces and lifetime of rsEGFP2 near and away from metallic nanoparticles to examine the plasmonic effect. We found that both switching contrast and the brightness of rsEGFP2 could be improved by silver nanoparticles, while no significant modification of rsEGP2 properties was observed in the case of gold nanorods which can be explained with the calculation of ratio between the scattering and absorption cross sections. Altogether our results open a new way to control RSFPs photophysical properties for super-resolution imaging
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.
Der volle Inhalt der QuelleThe 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
Dedeh, Amina. „Impact d'un sédiment dopé aux nanoparticules d'or ou de sulfure de cadmium sur un invertébré et un poisson d'eau douce“. Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0068/document.
Der volle Inhalt der QuelleThe aim of this thesis was to determine the impact of two types of metal nanoparticles (cadmium sulphide - CdS - and gold - Au) on two aquatic models (tubifex worms and zebrafish Danio rerio). The approach has been to dope the Garonne sediment with the two types of nanoparticles and characterize the effect of this contamination on the two animals using multiple markers at different levels of biological organization (biochemical responses, neurotransmission activity, genotoxicity, gene expression and bioturbation activity). The effects were evaluated after exposure to contaminated sediment in experimental microcosms systems for twenty days. In a number of cases this work revealed an effect of the nanoparticles that was not due to metal but to the nanoparticulate properties. Indeed, in the case of CdS nanoparticles, we observed alterations in the genome as well as the modification of the bioturbation activity of worms tubifex in response to the contamination of nanoparticles but not to that of the ionic form. In this work we observed the release of gold nanoparticles from the sediment into the water column, and its potential bioavailability to fish. These nanoparticles were causing DNA damage in both organisms, modifying the expression of certain genes and increased acetylcholinesterase activity in zebrafish. Bioturbation results showed no effects of gold nanoparticles on the movement of worms
Juvé, Vincent. „Spectroscopie linéaire et ultra-rapide de nanoparticules métalliques : de l’ensemble au nano-objet individuel“. Thesis, Lyon 1, 2011. http://www.theses.fr/2011LYO10163/document.
Der volle Inhalt der QuelleThe size reduction of metals, from bulk to nanoparticles, induces significant modifications of their properties. For instance, the optical properties evolve and a new resonance, the localized surface plasmon resonance, appears in the optical spectrum and is responsible for the change of colors of metallic nanoparticles. This work is focused on studies of metals’ properties at the nanometric scale. In the first part, the vibrational and thermal properties are studied with a femtosecond spectroscopy technique. It is shown that it is possible to excite and detect optically vibrational frequencies in the terahertz domain by studying platinum nanoparticles formed by less than 100 atoms. The study of the thermal properties of the metallic nanoparticles (gold and silver) has shown that the boundary effect increases. This thermal boundary resistance, known as the Kapitza resistance, plays a dominant role in the heat transfer at the nanometric scale. A correlation between the experimental values of the thermal boundary resistance and the acoustic impedances of the boundary’s materials has been found. We have also shown that the Kapitza resistance is a decreasing function of the temperature in the 70-300K range. In the second part, the effect of the size reduction on the optical properties of non-spherical nanoparticles is observed. The Spatial Modulation Spectroscopy technique is used in order to locate and study individual gold nanorods. It is shown that the two geometrical parameters (the length and the diameter) of the nanorods influence the spectral linewidth of the localized surface plasmon resonance. This effect is not predicted by existing classical or quantum models
Gu, Yingying. „Membranes polymères fonctionnalisées par des poly(liquide ionique)s et des nanoparticules de palladium : applications au captage de CO2 et aux membranes catalytiques“. Thesis, Toulouse 3, 2015. http://www.theses.fr/2015TOU30157/document.
Der volle Inhalt der QuellePolymeric support membranes were modified via photo-grafting by poly(ionic liquid)s (polyILs), featuring in the capability to separate CO2 from other gases and to stabilize metallic nanoparticles (MNPs). For CO2 capture, a thin polyIL-IL gel layer was homogenously coated on support hollow fibers. The composite fibers show high CO2 permeance and reasonable CO2/N2 selectivity. For the catalytic membrane, palladium NPs were generated inside a grafted polyLI layer. Compared to colloidal palladium system in a batch reactor, the catalytic membrane, as a contactor membrane reactor, is more efficient in terms of reaction time (ca. 2000 times faster), selectivity and MNP retainability. Theoretical study on reactor modeling, concentration & temperature profiles, and production capacity was done for an overall understanding of the catalytic membrane
Bakhti, Saïd. „Étude théorique des résonances plasmon de nanostructures métalliques et leur inscription lithographique par Microscopie à Force Atomique“. Thesis, Saint-Etienne, 2014. http://www.theses.fr/2014STET4022/document.
Der volle Inhalt der QuelleThe thesis presented in this manuscript concerns firstly the theoretical study of plasmon resonances of metal nanoparticles, and also an experimental study metallic nanostructures inscription based on the use of an Atomic Force Microscope. The theoretical part presents a new phenomenological approach for analyzing the resonant modes of unique particles and their coupling in simple structures. Numerical algorithms have been developed to extract the phenomenological parameters from the rigorous calculation of the field scattered by the particles. This methodology has been applied to various cases from the single particle to two dimensional particle arrays. The experimental section develops a metallic nanostructures inscription method based on electrolytic reduction of metal ions in meso-porous silica thin film, by applying a voltage between a conductive AFM tip and the conductive substrate supporting the film. Structures are formed on both sides of the silica layer, with the possibility to switch their position by a simple reversal of the applied potential. Moreover, it appears that this switching is accompanied by changes in the local conductivity of the silica layer. A consequence of the inscription process is the formation of metal filaments at the ends of AFM tips. In particular, gold filaments are obtained with sizes ranging from tens to hundreds of nanometers long with a few nanometers thick
Sirotkin, Sergey. „Low frequency modes from small nanoparticles (metal nanocrystals) to large nanospheres (viruses) : an inelastic light scattering study“. Phd thesis, Université Claude Bernard - Lyon I, 2010. http://tel.archives-ouvertes.fr/tel-00847063.
Der volle Inhalt der QuelleMansour, Sergui. „Methodological development in proteomics and lipidomics applied to the analysis of cultural heritage samples : photochemical synthesis of metallic nanoparticles in flow“. Thesis, Lille 1, 2018. http://www.theses.fr/2018LIL1R069.
Der volle Inhalt der QuelleMass spectrometry is a powerful analytical technique which allows to analyze different types of samples from different fields. In this work, we propose new developments in lipidomics and proteomics for the analysis of cultural heritage samples. The first part of this work describes a methodological development in proteomics applied to the analysis of archaeological samples. This work consists in optimizing the "bottom-up" strategy for the analysis of proteins residues trapped in archaeological ceramics preserved in unfavorable conditions for their conservation (for example: first century amphora preserved in a submarine environment). During this work, we studied non-sequenced organisms by adapting a de novo sequencing methodology and we succeeded to demonstrate by analytical evidence, and for the first time, the use of Dressel 14 amphorae for the transportation of fish belonging to Thunnus genus. In the second part, we present a new approach in lipidomics for the analysis and the identification of crosslinked polymer network present in linseed oil based paints. In this part, we developed a new method for soft depolymerization and derivatization of reticulated lipids, which are than analyzed with high resolution mass spectrometry (FT-ICR MS) to access into the 3D network formed by lipids in oil paint. The developed method was applied to an oil paint that dates back to the 19th century, and we also studied the interaction between lipids and pigments. The third part describes the development of a photochemical synthesis in flow of ultra-stable metallic nanoparticles (silver, gold and palladium) in organic medium
Cocq, Aurélien. „OléoSodioSuccinyl-Cyclodextrines : synthèse et applications en catalyse aqueuse de cyclodextrines amphiphiles obtenues par estérification à l'aide de dérivés oléiques maléinisés“. Thesis, Artois, 2017. http://www.theses.fr/2017ARTO0404/document.
Der volle Inhalt der QuelleThis thesis work consisted of the synthesis and valorisation of a new family of amphiphilic cyclodextrins in aqueous catalysis: OleoSodioSuccinyl-Cyclodextrins (OSS-CDs). These OSS-CDs were obtained in three main steps. The first step consisted of the thermal or rhodiocatalysed maleinisation of oleic acid or its methyl ester. The carbon-carbon double bond of the obtained substituted succinic anhydrides can then possibly be hydrogenated by rhodium on carbon catalysis. By reacting with native or modified cyclodextrins, these anhydrides led to cyclodextrin esters having carboxylic groups. The OSS-CDs, obtained by neutralisation with sodium hydroxide of these functions, have high aqueous solubilities ( 50-500 g.L-1 at 20° C), are surfactant (aggregation concentration: 4-360 g.L-1 at 20°C) and form aggregates in water. The fatty chains of these OSS-CDs have a strong tendency to include in the cavity of the cyclodextrin on which they are grafted. The OSS-CDs showed a very good mass transfer capacity in aqueous biphasic rhodiocatalysed hydroformylation of alpha-olefins, with higher reaction rates when using the OSS-CDs obtained from methyl oleate. Some OSS-CDs coming from oleic acid have been found to be very good stabilizers for ruthenium nanoparticles. The colloidal suspensions obtained with them were very stable, active in the hydrogenation of many substrates and can be recycled without loss of activity
Zhang, Luqiong. „Magnetic Molecular-based Materials Assembled on Metallic Substrates : Experimental X-ray Absorption Spectroscopy and Ligand Field Multiplet Calculations“. Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS587.
Der volle Inhalt der QuelleThis thesis is focused on the investigation of the magnetic properties of magnetic nanoparticles and spin crossover complexes assembled as monolayers on different metallic substrates by X-ray Absorption Spectroscopy (XAS) at the L₂,₃ edges of the metal atoms. We use X-ray Magnetic Circular Dichroism (XMCD) and X-ray Natural Linear Dichroism (XNLD) to do so. The simulation of the experimental data is carried out by Ligand Field Multiplet (LFM) calculations. This thesis is divided into two parts.The first part aims at studying the magnetic anisotropy of Prussian blue analog magnetic coordination nanoparticles that were assembled as a single layer on Highly Oriented Pyrolytic Graphite. XAS, XNLD and XMCD measurements disclose the presence of electronic and magnetic anisotropy by the opening of a magnetic hysteresis loop at low temperature. Combining experimental data with LFM calculations, we propose a structural model of the surface of the particles that allows accounting for electronic and magnetic anisotropy and that is proposed to be due to the single layer/vacuum interface.In the second part, thermal and light-induced spin crossover behavior of Fe(II) containing molecules have been assembled as a sub-monolayer on metallic substrates. Complementary LFM calculations and experimental XAS data allow unravelling the nature and the magnitude of the spin crossover as a function of the external stimuli (temperature, X-rays, blue and red light). An anomalous blue light effect allowing a crossover at low temperature from the high to low spin states is discovered and analyzed as being due to the interface between the molecules and the metallic substrates
Dedeh, Amina. „Impact d'un sédiment dopé aux nanoparticules d'or ou de sulfure de cadmium sur un invertébré et un poisson d'eau douce“. Electronic Thesis or Diss., Bordeaux, 2014. http://www.theses.fr/2014BORD0068.
Der volle Inhalt der QuelleThe aim of this thesis was to determine the impact of two types of metal nanoparticles (cadmium sulphide - CdS - and gold - Au) on two aquatic models (tubifex worms and zebrafish Danio rerio). The approach has been to dope the Garonne sediment with the two types of nanoparticles and characterize the effect of this contamination on the two animals using multiple markers at different levels of biological organization (biochemical responses, neurotransmission activity, genotoxicity, gene expression and bioturbation activity). The effects were evaluated after exposure to contaminated sediment in experimental microcosms systems for twenty days. In a number of cases this work revealed an effect of the nanoparticles that was not due to metal but to the nanoparticulate properties. Indeed, in the case of CdS nanoparticles, we observed alterations in the genome as well as the modification of the bioturbation activity of worms tubifex in response to the contamination of nanoparticles but not to that of the ionic form. In this work we observed the release of gold nanoparticles from the sediment into the water column, and its potential bioavailability to fish. These nanoparticles were causing DNA damage in both organisms, modifying the expression of certain genes and increased acetylcholinesterase activity in zebrafish. Bioturbation results showed no effects of gold nanoparticles on the movement of worms
Campbell, Paul. „Utilising the solvation properties of ionic liquids in the size-controlled synthesis and stabilization of metal nanoparticles for catalysis in situ“. Thesis, Lyon 1, 2010. http://www.theses.fr/2010LYO10212/document.
Der volle Inhalt der QuelleImidazolium based ionic liquids (ILs) consist of a continuous 3-D network of ionic channels, coexisting with non polar domains created by the grouping of lipophilic alkyl chains, forming dispersed or continuous microphases. The aim of this work is to use the specific solvation properties of ILs, related to this 3-D organisation, to generate and stabilise in situ metal nanoparticles (NPs) of a controlled and predictable size. This approach has found application in fields such as catalysis and microelectronics. The phenomenon of crystal growth of NPs (ruthenium, nickel, tantalum) generated in situ in ILs from the decomposition of organometallic complexes under molecular hydrogen, is found not only to be controlled by i) the size of non-polar domains, in which the complexes dissolve, but also by ii) the experimental conditions (temperature, stirring) and iii) the nature of the metal and its precursor complex. The previously unexplained stabilisation mechanism of NPs in ILs is found to depend on the mechanism of formation of NPs, which may lead to the presence of either hydrides or N-heterocyclic carbenes (NHC) at their surface. These have both been evidenced through isotopic labelling experiments analysed by NMR and mass spectrometry. Another advantage of ILs is that they provide an interesting medium for catalytic reactions. Studies on the influence of the IL on the catalytic performance in homogeneous catalysis have highlighted the crucial importance of the physical-chemical parameters of ILs, in particular the viscosity, for which a term must be included in the kinetic rate law. Using these findings, a thorough investigation of the effect of the NP size on catalytic activity and selectivity in hydrogenation in ILs was undertaken, confirming the importance of controlling NP size for catalytic applications
Nguyen, Tuyet Trang. „Utilisation de nanotubes de carbone pour la préparation de catalyseurs confinés“. Thesis, Toulouse, INPT, 2013. http://www.theses.fr/2013INPT0062/document.
Der volle Inhalt der QuelleThis thesis is refer of carbon nanotubes (CNTs) as a support to confine metal nanoparticles or as a template for the confinement of the active phase. Chapter I give a comprehensive review of the state of knowledge on the effects of confinement in CNTs. Chapter II describes the preparation and characterization of the metals (ruthenium, palladium and cobalt) confined inside CNTs catalysts. In this context, the study of the influence of various parameters such as operating conditions, nature of the metal or precursor or nanosupport pretreatment, on the selectivity of confinement is presented. Chapter III consists of two parts: one is devoted to the using of CNTs as a template for the synthesis of silica nanotubes (SNTs in the presence or absence of ruthenium particles confined in their channel). The other part is the immobilization of the catalyst (rhodium metallic complex) in an ionic liquid phase as active catalytic phase before filling in CNTs. Chapter IV concernes the application all catalyst-filled CNTs systems in the hydrogenation of cinnamaldehyde and 1-hexene reaction. The confinement effect on the catalytic performance is presented
Benghorieb, Soulef. „Modélisation des modifications des propriétés optiques de nouveaux matériaux nanostructurés par des particules métalliques“. Thesis, Saint-Etienne, 2011. http://www.theses.fr/2011STET4002.
Der volle Inhalt der QuelleThis thesis is devoted to modeling of the optical properties of nanostructured dielectrics by metal particles. We interested in two aspects of the problem: the determination of effective index and field distribution of plasmon nanoparticles dispersed in such media. We have developed two numerical approaches. The first is devoted to the simulation of real and imaginary parts of the effective index of heterogeneous medium. In order to compare experience and theory, we have proposed an experimental approach to measure the effective refractive index of colloidal solutions containing metal or semiconductor nanospheres. The second aspect deals with the method of extraction of the field plasmon on the surface of metal nanosphere when it is excited by electromagnetic plane wave. The calculated effective index and field plasmon are done in function of characteristic parameters of nanoparticles and host matrix
Sharma, Nipun. „Self-organization of silver nanoparticles with femtosecond laser in TiO2 matrix : Applications to plasmonic colours, multiple hidden images and Colour Image-Multiplexing“. Thesis, Lyon, 2020. http://www.theses.fr/2020LYSES032.
Der volle Inhalt der QuelleSelf-organization of metallic nanoparticles in a medium is an efficient and a low-cost way to produce plasmonic systems that can be used for applications to active colour display, image encoding, and security. Such nanocomposite systems must be synthesized in form of stable films which could be coated on any kind of surface for laser processing. This doctoral thesis focuses on laser‐induced self‐organization of nanocomposite thin films of silver and mesoporous titania.In this work, we first investigate synthesizing mesoporous TiO2 thin films using hydrolytic process, which is easy to implement, to provide crystallized films starting at 100°C. First activation energies in mesoporous TiO2 films using Raman spectroscopy in combination with the phonon quantum confinement model are reported in this work. Further, growth mechanisms of nanocrystals in mesoporous TiO2 films are investigated in form of ellipsometric measurements highlighting its effect on film porosity and crystallinity with annealing temperature.The second study demonstrates fabrication of different nanocomposite structures using femtosecond laser scanning technique, triggering growth and self-organization of silver nanoparticles inside porous amorphous titania matrix giving rise to plasmonic dichroic colours. Further investigation on the parametric study of such nanocomposites gives rise to different nanostructures at two different scan speed regimes, which are formed at the surface and are embedded below due to excitation of surface and the guided modes. The flexibility of this laser-based marking technology also allows to fabricate hybrid nanostructures composed of different adjacent nanostructure types, interlaced to cover large areas. An extension of this study is concluded on plastic/flexible substrates to encode diffractive printed images. Here surface nanostructures (LIPSS) are formed by using the control of laser polarization and thus grating orientation, which is used to encode grey-level images that can be observed in diffraction modes.Further, this study is concluded by producing three image multiplexing which can be observed in three selected modes of observation under white light in reflection with non-polarized light and transmission between polarizers for two different polarization angles. This is due to the fact that the film birefringence and dichroism can be controlled to produce unprecedented colour gamuts for multiplexing. Such smart laser processing on nanocomposite thin films gives rise to artistic and security applications by encoding different images up to three under same area
Tambosi, Reem. „Stress and toxicity of metal in photosynthetic bacteria : multi-scale study of the effects and the targets of metal ions and nanoparticles Silver and Copper Acute Effects on Membrane Proteins and Impact on Photosynthetic and Respiratory Complexes in Bacteria Silver Effect on Bacterial Cell Membrane Structure Investigated by Atomic Force and Scanning Electron Microscopes Cadmium and Copper Cross-tolerance. Cu+ alleviates Cd2+ toxicity, and both cations target heme and chlorophyll biosynthesis pathway in Rubrivivax gelatinosus Additive effects of metal excess and superoxide, a highly toxic mixture in bacteria“. Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASL070.
Der volle Inhalt der QuelleThe extensive use of metal ions in industry and agriculture represents a serious threat to the environment and to all living being because of the acute toxicity of these ions. However, it can also be a promising tool, silver ions and nanoparticles are some of the most widely used metals in various industrial and health applications. The antimicrobial effect of these nanoparticles is in part related to the released Ag⁺ ions and their ability to interact with bacterial membranes. The goal of this project is to study the interaction between biological subject (the bacteria) and physical objects (metals), and more specifically to understand the impact of metals in different forms (ions, nanoparticles and nanostructures) on the growth of the bacterial cells using different approaches : physiology, biochemistry, genetics and cell biology. We used as biological models, principally the purple photosynthetic bacterium Rubrivivax (R.) gelatinosus, but also Escherichia coli; and for physical objects, we used silver as main metal but also other metals (copper, cadmium and nickel) for comparison. The main objectives are: 1- to study the impact and the mechanisms of toxicity of these metallic ions/NPs on the bacterial respiratory and photosynthesis metabolisms. 2- To identify the bacterial genes involved in response to excess silver. 3- To study the internalization and interaction of metals ions and NPs within biological membranes. The results showed that we were able to identify, both in vitro and in vivo, specific targets of Ag⁺ and Cu²⁺ ions within the membrane of bacteria. This include complexes involved in photosynthesis, but also complexes involved in respiration. Ag⁺ and Cu²⁺ were shown to specificaly target a solvent exposed bacteriochlorophyll in the light harvesting antennae of the photosystem. This also presents, in our knowledge, the first direct evidence of silver ions damages to membrane proteins involved in these metabolisms. We also carried out a microscopy (AFM/ SEM) comparative study of the effect of Ag⁺ ions or Ag-NPs synthesized in our laboratory, on the bacterial cell morphology
Marepally, Bhanu Chandra. „Production of Solar Fuels using CO2“. Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE1062.
Der volle Inhalt der QuelleIn view of the recent alarming rate of depletion of fossil fuel reserves and the drastic rise in the CO2 levels in the atmosphere leading to global warming and severe climate changes, tapping into all kinds of renewable energy sources has been among the top priorities in the research fields across the globe. One of the many such pathways is CO2 reduction to fuels using renewable energies, more commonly referred as photo-electro-catalytic (PEC) cells. Experimental tests were carried out on various types of catalysts in both the gas and liquid phase cells (lab-designed) to understand the different selectivity, productivity and the reaction products obtained. For the studies on the EC reduction of CO2 in gas phase cell, a series of electrodes (based on Cu, Fe, Pt and Cu/Fe metal nanoparticles – NPs - deposited on carbon nanotubes – CNTs - or carbon black and then placed at the interface between a Nafion membrane and a gas-diffusion-layer) were prepared. Under gas phase, the formation of ≥C1 products (such as ethanol, acetone and isopropanol) were observed, the highest being for Fe and closely followed by Pt, evidencing that also non-noble metals can be used as efficient catalysts under these conditions. To enhance the net fuels, a different set of electrodes were also prepared based on substituted Zeolitic Imidazolate (SIM-1) type MOF coatings (MOF-based Fe-CNTs, Pt-CNTs and Cu/Fe-CNTs) and Pt-MOF showed improved fuels. Moving to the studies on the EC reduction of CO2 in liquid phase cell, a similar set of electrodes were prepared (metal NPs of Cu, Fe, Pt, Ru and Co deposited on CNTs or carbon black). For liquid phase conditions, in terms of net C-products, catalytic electrodes based on Pt topped the class, closely followed by Ru and Cu, while Fe got the lowest position. The probable underlying reaction mechanism was also provided. In order to improve further the performances, varied sized metal NPs (Ru, Fe, Pt and Cu) have been synthesized using different techniques: (i) impregnation (ImR) route to achieve NPs in the size range of 10-50 nm; (ii) organometallic (OM) approach to synthesize uniform and ultrafine NPs in the size range of 1-5 nm (i.e., Fe NPs were synthesized through a novel synthesis route to attain 1-3 nm NPs); (iii) Nanowire (NW) top-down approach to obtain ultrafine copper metal NPs in the size range of 2-3.8 nm. The enhancements in the fuel productivity were found to be 5-30 times higher for the smaller metal NPs over the larger metal NPs and moreover, with reduced metal loading from 10 to 1-2 wt %. A different set of electrodes based on nano-foams (Cu NF and Fe NF on Cu foil, Fe foil, Al foil, Inconel foil and Al grid/mesh) prepared via electro-deposition were also investigated, to further improve CO2 to fuels conversion. After, optimization of deposition and voltage using cyclic voltammetry, the fuels improved by 2-10 times over the highest net fuels achieved using metal NPs doped CNT electrodes