547 research outputs found
The construction of Karen Karnak: The multi-author-function
No full textThis thesis is situated within the comparatively recent developments of Web 2.0 and the emergence of interactive WikiMedia, and explores the mode of authorship within a Read/Write culture compared to that of a Read/Only tradition. The hypothesis of this study is that the role of the audience has become merged with the author, and as such, represents new functions and attributes, distinct from a more conventional concept of authorship, in which the roles of audience and author are more separate. Read/Write and participatory culture, as defined by this study, is focused on collaboration, and includes the influences of D.I.Y. culture, Open-Source practices and the production of text by multiple authors. Multi-authorship presents a re-thinking of several concepts which support the notion of the individual author, since the focus of multi-authorship is not on attribution and ownership of a finished text, but on the continued malleability of a text. Modes of multi-authorship, demonstrated in the use of the pseudonyms Alan Smithee and Karen Eliot, represent declarative authors whose names signify multiple origins, whilst concurrently indicating a distinct body of work. The function of these names form an important context to this study, since primary research involves the construction of an experimental mode of multi-authorship utilising WikiMedia technology and the interaction of thirty nine participants, who are invited to create a body of work under the collective pseudonym Karen Karnak. The data generated by this experiment is analysed using aspects of Michel Foucault's author-function to identify and determine power structures inherent in the WikiMedia context. The interplay of power structures, including concepts such as identity, ownership and the body of work, affect the resulting mode of authorship and contribute to the construction of Karen Karnak, suggesting further areas of research into the emerging multi-author
The Magazine Women Believed in: "Marriage Advice" 1950-1955
No full textIn the United States society, the 1950s is seen as a time of great conservatism where both men and women were placed into specific gender roles that dictated much of how they lived their lives. One institution that verified these gender roles and stereotypes to be true was women's magazines. These magazines contained sections such as fashion segments, helpful cooking guidelines, advertisements, and advice columns that seemed to target middle class, white, suburban married housewives. One advice column that seemed to particularly focus on the idea of a happy housewife and married life was the column Making Marriage Work, which appeared in the magazine Ladies Home Journal during this 1950s time period. The author of this column, Clifford R. Adams, idealized the 1950s perfect housewife existence and through his advice he encouraged women to strive for this lifestyle, while there were other sources demonstrating that this perceived notion of the perfect housewife did not exist during the 1950s time period
Alexa Discussion Board Skill
No full textabstract: A common challenge faced by students is that they often have questions about course material that they cannot ask during lecture time. There are many ways for students to have these questions answered, such as office hours and online discussion boards. However, office hours may be at inconvenient times or locations, and online discussion boards are difficult to navigate and may be inactive. The purpose of this project was to create an Alexa skill that allows users to ask their Alexa-equipped device a question concerning their course material and to receive an answer retrieved from discussion board data. User questions are mapped to discussion board posts by use of the cosine similarity algorithm. In this algorithm, posts from the discussion board and the user’s question are converted into mathematical vectors, with each term in the vector corresponding to a word. The values of these terms are computed based on the word’s frequency within the vector’s corresponding document, the frequency of that word within all the documents, and the length of the document. After the question and candidate posts are converted into vectors, the algorithm determines the post most similar to the user’s question by computing the angle between the vectors. With the most similar discussion board post determined, the user receives the replies to the post, if any, as their answer. Users are able to indicate to their Alexa device whether they were satisfied by the answer, and if they were unsatisfied then they are given the opportunity to either rephrase their question or to have the question sent to a database of unanswered questions. The professor can view and answer the questions in this database on a website hosted by use of Amazon’s Simple Storage Service. The Alexa skill does well at answering questions that have already been asked in the discussion board. However, the skill depends heavily on the user’s word choice. Two questions that are semantically identical but different in phrasing are often given different answers. This is because the cosine algorithm measures similarity on the basis of word overlap, not semantic meaning, and thus the application never truly “understands” what type of answer the user desires. Improving the performance of this Alexa skill will require a more advanced question answering algorithm, but the limitations of Amazon Web Services as a development platform make implementing such an algorithm difficult. Nevertheless, this project has created the basis of a question answering Alexa skill by demonstrating a feasible way that the resources offered by Amazon can be utilized in order to build such an application
Author Correction: Hippocampal oxytocin receptors are necessary for discrimination of social stimuli
No full textThe original version of this Article contained an error in the spelling of the author Alexa H. Veenema, which was incorrectly given as Alexa Veenema. This has now been corrected in both the PDF and HTML versions of the Article.</jats:p
Interchromophoric Interactions Between TMR, Alexa, and BODIPY Fluorophores
No full textabstract: The fundamental photophysics of fluorescent probes must be understood when the probes are used in biological applications. The photophysics of BODIPY dyes inside polymeric micelles and rhodamine dyes covalently linked to proteins were studied. Hydrophobic boron-dipyrromethene (BODIPY) dyes were noncovalently encapsulated inside polymeric micelles. Absorbance and fluorescence measurements were employed to study the photophysics of these BODIPY dyes in the micellar environments. Amphiphilic polymers with a hydrophobic character and low Critical Micelle Concentration (CMC) protected BODIPYS from the aqueous environment. Moderate dye loading conditions did not result in ground-state dimerization, and only fluorescence lifetimes and brightnesses were affected. However, amphiphilic polymers with a hydrophilic character and high CMC did not protect the BODIPYS from the aqueous environment with concomitant ground-state dimerization and quenching of the fluorescence intensity, lifetime, and brightnesses even at low dye loading conditions. At the doubly-labeled interfaces of Escherichia coli (E. coli) DNA processivity β clamps, the interchromophric interactions of four rhodamine dyes were studied: tetramethylrhodamine (TMR), TMR C6, Alexa Fluor 488, and Alexa Fluor 546. Absorbance and fluorescence measurements were performed on doubly-labeled β clamps with singly-labeled β clamps and free dyes as controls. The absorbance measurements revealed that both TMR and TMR C6 readily formed H-dimers (static quenching) at the doubly-labeled interfaces of the β clamps. However, the TMR with a longer linker (TMR C6) also displayed a degree of dynamic quenching. For Alexa Fluor 546 and Alexa Fluor 488, there were no clear signs of dimerization in the absorbance scans. However, the fluorescence properties (fluorescence intensity, lifetime, and anisotropy) of the Alexa Fluor dyes significantly changed when three methodologies were employed to disrupt the doubly-labeled interfaces: 1) the addition of sodium dodecyl sulfate (SDS) detergent to denature the proteins, 2) the addition of clamp loader (γ complex) to open one of the two interfaces, and 3) the use of subunit exchange to decrease the number of dyes per interface. These fluorescence measurements indicated that for the Alexa Fluor dyes, other interchromophoric interactions were present such as dynamic quenching and homo-Förster Resonance Energy Transfer (homo-FRET).Dissertation/ThesisDoctoral Dissertation Chemistry 201
University of Chicago East Asia by the Book! Author Talk: Shakespeare and East Asia, Tuesday May 25, 2021 at 5 pm CDT / 6 pm EDT
No full textRegister at https://uchicagogroup.zoom.us/webinar/register/WN_jyEzkIZYQZ6bKzjjr3faZg :::: The University of Chicago East Asia by the Book! Author Talks is proud to present a book launch of Alexa Alice Joubin's Shakespeare and East Asia (Oxford University Press). Chair: Haun Saussy (University of Chicago). Discussant: Michael Saenger (Southwestern University). The event is co-sponsored by the Seminary Co-Op Bookstore. ::::: How did Kurosawa influence George Lucas' Star Wars? Why do critics repeatedly use the adjective Shakespearean to describe Gong Joon-ho's film Parasite (2019)? How do East Asian cinema and theater portray vocal disability and transgender figures
Rational design and characterization of Cu and Cu@ZnO nanocatalysts for CO2 hydrogenation to methanol
No full textDepuis plusieurs décennies, le domaine des nanomatériaux connaît un véritable essor auprès de la communauté scientifique. Leur dimension nanométrique ouvre à de nouvelles propriétés physico-chimiques qui diffèrent de leurs homologues massifs ou encore offre l’amélioration de propriétés déjà existantes. De ce fait, les nanomatériaux se sont très rapidement imposés dans un grand nombre de domaines dont la catalyse. Les nanocatalyseurs (NCs) à base de cuivre sont particulièrement attrayants dans ce domaine. Contrairement aux matériaux historiquement utilisés en catalyse (platine, palladium, or, argent), le cuivre à une importante abondance naturelle ce qui fait de lui un matériau peu coûteux aux propriétés catalytiques intéressantes et il est au cœur de procédés catalytiques d’intérêt économique et environnemental. Par exemple, ces dernières décennies, la réaction d'hydrogénation du CO2 suscite un véritable intérêt pour réduire les émissions de CO2 via son recyclage en matières premières chimiques à plus hautes valeurs ajoutées telles que le méthanol. L’implémentation de cette réaction à l’échelle industrielle nécessite l’utilisation d’un catalyseur composé de cuivre tel que : Cu/ZnO/Al2O3. L'évolution structurelle des nanocatalyseurs dans les conditions de réaction nuit à leurs performances, complique la compréhension des mécanismes réactionnels et l’identification des différents sites actifs présents à la surface du catalyseur. Les catalyseurs modèles de types ZnO/Cu(111) ont été largement étudiés dans la littérature pour simplifier la compréhension des mécanismes réactionnels, mais ont souvent échoués à prendre en compte l’effet sur la réaction que peuvent avoir certains paramètres structurels tels que : la taille des particules, leur cristallinité ainsi que leur morphologie et la nature des interfaces,. Dans ce contexte, nous avons élaboré des NCs Cu-ZnO de structures contrôlées afin d'atténuer les divergences entre les catalyseurs modèles généralement étudiés dans la littérature et les catalyseurs réels. Ainsi, nous rapportons dans ce manuscrit de thèse, la synthèse rationnelle de nanoparticules (NPs) de Cu par voie chimique. L’influence de différents paramètres expérimentaux – tels que la température de réaction, la vitesse de montée en température ou encore la nature et la concentration des précurseurs et des ligands utilisés – sur le contrôle de taille, de cristallinité et de morphologie, est discutée. Nous présentons dans un second temps, la synthèse de NPs cœur-coquille de Cu@ZnO par une méthode de croissance par germination à partir de germes de Cu de morphologies cubiques et sphériques, avec des taux de couvertures en ZnO variables. Par la suite, nous avons étudié l’effet de l’exposition des gaz réactionnels et de la température sur l’évolution structurelle des interfaces Cu-ZnO avec des catalyseurs modèles d’épaisseurs variables. Le suivi par XPS de l’hydrogénation du CO2 sur ces catalyseurs, nous a permis de sonder les différents intermédiaires réactionnels présents à la surface des catalyseurs en fonction de l’épaisseur des films et de définir un modèle de mécanisme réactionnel prenant en compte l’influence de la morphologie et son évolution à différentes températures. Enfin, nous avons étudié les propriétés catalytiques des NCs Cu@ZnO dans les conditions réelles de la réaction d’hydrogénation de CO2 et l’effet de leur propriétés structurelles, telles que leur cristallinité et leur morphologie, sur la réactivité et la sélectivité.For the past several decades, the field of nanomaterials has experienced remarkable growth in the scientific community. Their nanometric dimension paves the way to new physico-chemical properties that differ from their bulk counterparts or leads to the improvement of already existing properties. As a result, nanomaterials have rapidly gained importance in a large number of fields, including catalysis. Copper and copper-based nanocatalysts (NCs) are particularly attractive in this field. Unlike the materials historically used in catalysis (platinum, palladium, gold, silver), copper has a high natural abundance which makes it a less expensive material with interesting catalytic properties and is currently at the center of catalytic processes of great economic and environmental interest. For example, in the last decades, the CO2 hydrogenation reaction has gained a lot of interest to reduce CO2 emissions by converting it into higher value-added feedstock chemicals such as methanol. The implementation of this reaction on an industrial scale requires the use of a copper catalyst such as Cu/ZnO/Al2O3.The structural evolution of the NCs under the reaction conditions hinders their performance and complicates the understanding of the reaction mechanisms and the identification of the different active sites present on the catalyst surface. Model catalysts such as ZnO/Cu(111) have been widely studied in the literature to try and simplify the understanding of the reaction mechanisms, but have often failed to take into account the effect on the reaction of structural parameters such as particle size, crystallinity, and morphology as well as the interface. In this context, we have developed Cu-ZnO NCs with controlled structures in order to mitigate the discrepancies between the model catalysts generally studied in the literature and the real catalysts. Thus, we report in this thesis manuscript, the rational synthesis of Cu nanoparticles (NPs) by chemical route. The influence of different experimental parameters - such as the reaction temperature, the heating rate or the nature and concentration of precursors and ligands - on the size, crystallinity and morphology control is discussed. Furthermore, we present the synthesis of Cu@ZnO core-shell NPs by a seed mediated growth method from cubic and spherical Cu NP seeds with variable ZnO coverages. Subsequently, we investigated the effect of reaction gas exposure and temperature on the structural evolution of Cu-ZnO interfaces with model catalysts of varying thicknesses. XPS monitoring of CO2 hydrogenation on these catalysts allowed us to probe the different reaction intermediates present on the surface of the catalysts as a function of the film thickness and to define a model of the reaction mechanisms which takes into account the influence of the catalysts’ morphology and its evolution under different temperatures. Finally, we studied the catalytic properties of Cu@ZnO NCs under the real industrial conditions for CO2 hydrogenation reaction and the effect of their structural properties, such as their crystallinity and morphology, on their reactivity and selectivity
Optical, spectroscopic and electrochemical property three-dimensional self-organized
No full textCette thèse se concentre sur la caractérisation d'assemblages organisés de nanoparticules plasmoniques appelés supracristaux. Les nanoparticules utilisées mesurent entre 5 et 11 nm de diamètre et possèdent une distribution en taille étroite permettant leur organisation à trois dimensions. Une fois les supracristaux obtenus, nous avons mesuré les spectres d'absorbance de supracristaux individuels constitués de différentes nanoparticules : cuivre, argent et or. Un modèle théorique simple a été utilisé pour calculer les spectres d'absorbance à partir de données disponibles dans la littérature. Nous avons ensuite montré que les supracristaux de nanoparticules d'argent ou d'or constituent de nouveaux substrats présentant un grand intérêt pour des applications en Spectroscopie Raman Exaltée de Surface (SERS). Les tailles des nanoparticules utilisées sont en effet beaucoup plus petites que celles reportées dans la littérature, d'où un nombre plus important de points chauds et donc une grande sensibilité. En vue d'applications couplées électrochimie/Raman, nous avons également mesuré les spectres de réflectance sous potentiel. De plus, des mesures par AFM conducteur et par microscopie électrochimique montrent que la conductivité des assemblages est faible mais autorise néanmoins des transferts d'électrons entre les supracristaux les plus fins et une sonde redox en solution. Enfin, des expériences de microscopie holographique ont permis de suivre la formation de ces édifices en solution.This thesis focuses on the characterization of organized assemblies of plasmonic nanoparticles called supracrystals. The nanoparticles have a diameter ranging from 5 to 11 nm diameter and a narrow size distribution allowing their organization at three dimensions. Once the supracrystals were obtained, we measured the absorbance spectrum of individual supracrystals made of various nanoparticles: copper, silver or gold. A simple theoretical model was used to calculate the absorbance spectrum from available data in the literature. We then demonstrated that the supracrystals made of silver or gold nanoparticles are suitable substrates for Surface Enhanced Raman Spectroscopy applications. The sizes of the nanoparticles we use are indeed much smaller than in the literature, so that the number of hot spots and thus the sensitivity are increased. In view of coupling electrochemistry and Raman spectroscopy for future applications, we also measured the reflectance spectrum under potential control. Moreover, conductive AFM and Scanning ElectroChemical Microscopy measurements demonstrate that even if the conductivity of the supracrystals is weak, electron transfers between thin supracrystals and a redox probe in solution are nevertheless possible. Finally, holographic microscopy experiments allowed to follow the formation of these structures inside the solution
Synthèse rationnelle de nanocristaux bimétalliques plasmoniques/catalytiques pour la catalyse
No full textParmi les différents nanocatalyseurs, ceux constitués de nanoparticules de métaux nobles méritent une attention particulière en raison de leurs propriétés électroniques, chimiques et même optiques (dans le cas de transformations renforcées par les plasmons). Le platine ou le palladium sont bien connus pour leurs remarquables propriétés catalytiques, mais ils sont chers et leurs ressources sont limitées. En outre, les nanocatalyseurs monométallique ne peuvent conduire qu'à une gamme limitée de réactions chimiques. Ainsi, notre stratégie a été de développer des nanocatalyseurs bimétalliques composés de deux éléments métalliques qui peuvent présenter des effets synergiques entre leurs propriétés physicochimiques et une activité catalytique accrue. Nous avons ainsi conçu des nanocatalyseurs bimétalliques de type cœur-coquille composés d'un cœur en argent et d'une coquille en platine. L'intérêt est de combiner les activités catalytiques élevées et efficaces de la coquille de platine avec le cœur d'argent hautement énergétique, capable de renforcer les activités de la coquille grâce à ses propriétés plasmoniques. En outre, ces nanoparticules bimétalliques présentent souvent une activité catalytique supérieure en raison de la modification de la distance inter-atomique Pt-Pt (c'est-à-dire l'effet de contrainte). Dans ce travail de thèse, les nanoparticules Ag@Pt ont été synthétisées via un processus en deux étapes utilisant d'une part des nanoparticules d'Ag synthétisées chimiquement comme germes et d'autre part des complexes platine-oleylamine qui sont ensuite réduits à la surface des germes à une température contrôlée. Différentes tailles de germes d'Ag de 8 à 14 nm avec une très faible distribution de taille (<10%) ont été obtenues en ajustant le temps de réaction, la rampe de température, la concentration en précurseur d'Ag et la température finale pendant la synthèse. Différentes épaisseurs de coquille (de 1 à 6 couches atomiques) ont été obtenues en ajustant le rapport entre les concentrations de précurseur de platine et de germe d'argent. L'activité catalytique des nanoparticules Ag@Pt a été testée en considérant une réaction modèle de réduction du 4-nitrophénol en 4-aminophénol par NaBH4 en phase aqueuse. Nous avons observé que l'épaisseur de la coquille de Pt et la taille du noyau d'Ag influençaient les propriétés catalytiques et conduisaient à une activité catalytique accrue par rapport à l'argent ou au platine pur. Ceci a été attribué à des effets synergiques. De plus, nous avons observé une augmentation de l'activité catalytique des nanoparticules Ag et Ag@Pt sous irradiation lumineuse. Ce phénomène a été corrélé à la génération d'électrons chauds dans les noyaux d'Ag. Afin de développer une plateforme de nanocatalyse supportée, nous avons fabriqué des auto-assemblages 3D appelés aussi supercristaux composés de nanoparticules d'Ag@Pt obtenus spontanément après dépôt sur un substrat solide en raison de leur distribution de taille étroite et de leur forme homogène. L'activité catalytique de ces supercristaux pour la réaction d'évolution de l’hydrogène (HER) a été étudiée en suivant in situ par microscopie optique la production de nanobulles de gaz H2. Trois comportements distincts dans l'activité photo-catalytique (activité, activité intermittente et non-activité) ont été observés sur les supercristaux dans la même région d'intérêt. En outre, 50 % des assemblages ont été déterminés comme étant actifs pour l'HER qui a été démontrée comme étant accompagnée par une corrosion oxydative de l’argent.Among several nanocatalysts, those based on noble metal NPs deserve particular attention because of their electronic, chemical and even optical properties (in the case of plasmonic-enhanced transformations). Platinum or palladium are well known for their remarkable catalytic properties, but they are expensive and their resources are limited. In addition, single component nanocatalysts can only lead to a limited range of chemical reactions. Thus, our strategy was to develop bimetallic nanocatalysts composed of two metal elements that can exhibit synergistic effects between their physicochemical properties and enhanced catalytic activity. We have thus designed bimetallic nanocatalysts of the core-shell type composed of a silver core and a platinum shell. The interest is to combine the high and efficient catalytic activities of the platinum shell surface with the highly energetic silver core capable of enhancing the activities of the shell through its plasmonic properties. In addition, these bimetallic NPs often exhibit superior catalytic activity due to the modification of the Pt-Pt atomic bonding distance (i.e. the strain effect). In this thesis work, Ag@Pt NPs have been synthesized via a two-step process using chemically synthesized spherical Ag NPs as seeds on the one hand and platinum complexes with oleylamine on the other hand which are then reduced on the surface of the seeds at a controlled temperature. Different Ag seed sizes from 8 to 14 nm with a very low size distribution (<10%) have been obtained by adjusting the reaction time, temperature ramp, Ag precursor concentration and final temperature during the synthesis. The control of the shell thicknesses (from 1 to 6 atomic layers) has been possible by adjusting the ratio of platinum precursor to silver seed concentrations. The catalytic activity of the core-shell Ag@Pt NPs was tested by a model reaction of reduction of 4-nitrophenol to 4-aminophenol by NaBH4 in aqueous phase. We have observed that the thickness of the Pt shell and the size of the Ag core influence the catalytic properties and led increased catalytic activity compared to pure silver or platinum. This was attributed to synergistic effects. Furthermore, we have observed an enhancement of the catalytic activity of Ag and Ag@Pt NPs under light irradiation. This is correlated to the generation of hot electrons in the Ag core. Finally, in order to develop a supported nanocatalysis platform, 3D self-assemblies also called supercrystals composed of Ag@Pt nanoparticles have been spontaneously obtained after deposition on a solid substrate due to their narrow size distribution and homogeneous shape. The catalytic activity of these supercrystals for the hydrogen evolution reaction (HER) has been studied by following in situ by optical microscopy the production of H2 gas nanobubbles. Three distinct behaviors in photo-catalytic activity (activity, intermittent activity and non-activity) have been observed on the supercrystals in the same region of interest. In addition, 50% of the assemblies were determined to be active for HER which was shown to be accompanied by oxidative corrosion of silver
Noble metals nanoparticles organization : application to surface enhanced Raman spectroscopy and electrochemistry
No full textLes nanoparticules (NPs) métalliques ont fait l’objet d’un intérêt important ses dernières années dans des domaines variées tels que la santé, l’environnement ou l’électronique. Dans cette thèse, nous nous sommes particulièrement intéressés à l'application de NPs de métaux nobles mono ou bimétalliques dans le domaine de la plasmonique. Pour cela, nous avons synthétisé par voie organométallique des nanoparticules monométalliques d'or, d'argent et de cuivre d'une taille comprise entre 5 et 11 nm et caractérisées par une distribution en taille étroite. Après dépôt sur un substrat solide, elles s’organisent ainsi spontanément à 3D formant des supercristaux individuels. Nous avons étudié les propriétés optiques de ces supercristaux, en mesurant leurs spectres d'absorbances en fonction de leur épaisseur et de la nature des nanoparticules. Nous avons ensuite montré que ces supercristaux pouvaient être utilisés comme substrats SERS. La taille moyenne des nanoparticules étant beaucoup plus petites que celles reportées dans la littérature, ces substrats présentent un plus grand nombre de points chauds. On observe de plus un signal uniforme et reproductible d’un supercristal à l’autre. Les spectres Raman des ligands (alcanethiols ou alkylamines) ont été enregistrés et des facteurs d’exaltations entre 103 et 104 ont été calculés. Après vérification par electroreflectance de la stabilité des NPs sur une large gamme de potentiels, nous avons couplé le SERS à l'électrochimie en utilisant comme électrode une monocouche ordonnée de NPs d'or. Les taux de couvertures pour deux molécules différentes adsorbées sur les NPs ont été ainsi calculés. De plus nous avons pu suivre et confirmer la formation des espèces au cours des réactions d'oxydoréduction des molécules adsorbées en surface par SERS. Finalement nous avons synthétisé des NPs cœur-coquille Au@Ag, Ag@Au et d'alliage Cu-Au en utilisant comme germes les nanoparticules d’or, d’argent et de cuivre. Les structures et compositions chimiques de ces particules ont été étudiées. Leurs spectres optiques ont été mesurés par spectroscopie UV-Visible et simulés par calcul DDA (Discrete Dipole Approximation). Ils confirment la formation soient de structures cœur-coquille soient d’alliage. Par spectroscopie Raman basse fréquence, pour les NPs Au@Ag, nous montrons un couplage entre le cœur et la coquille en accord avec un modèle core shell développé dans la littérature. Pour les nanoparticules Cu-Au, le signal Raman basse fréquence est en accord avec la formation d’un alliage.Metallic nanoparticles (NPs) have been subjected to a growing interest these last years in various domains such as healthcare, environment or electronics. In this thesis, we were particularly interested in the application of NPs mono or bimetallic made of noble metals in plasmonic domain. In this way, we synthesized by organometallic route, monometallic NPs of gold, silver and copper with a diameter ranging from 5 to 11 nm and characterized by a narrow polydispersity. After deposition on a solid substrate, they organized themselves spontaneously in 3D forming individual supercrystals. We studied the optical properties of these supercrystals, by measuring their absorbance spectra in function of their thicknesses and the nature of the NPs. Then, we showed that these supercrystals can be used as SERS substrates. The mean diameter of the NPs is way smaller than the ones reported in the literature. These substrates display a uniform and reproductible signal from a supercrystal to another. The Raman spectra of coating agent (alkanethiols or alkylamines) have been collected and enhancement factor ranging from 103 to 104 have been calculated. After verification by electroreflectance of NPs stability over a wide potential range, we coupled SERS with electrochemistry by using a monolayer of organized gold NPs as an electrode. Coverage rates for two different molecules adsorbed on the NPs have been calculated. Moreover, we could follow and confirm the species formation during the oxydoreduction reactions of the adsorbed molecules by SERS. Finally, we synthesized core-shell NPs Au@Ag, Ag@Au and alloy NPs Cu-Au by using gold, silver and copper NPs as seeds. Their structures and chemical compositions have been studied. Their optical spectra have been measured by UV-Visible spectroscopy and simulated by DDA (Discrete Dipole Approximation). They confirmed the core-shell and alloy structures. By low frequency Raman spectroscopy, for the Au@Ag NPs, we showed a coupling between the core and the shell in accordance with the core-shell model developed in the literature. For the Cu-Au NPs, low-frequency Raman signal is in agreement with the formation of an alloy
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