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35 results on '"Brasiliense, Vitor"'

6. Functionalization and Crosslinking of Reduced Graphene Oxide Sheets by Multiple Tetrazine Units to Improve the Energy Storage in Supercapacitors.

Author

Bosmi, Margarita, Adeniji, Ademola, Michel, Elise, Brosseau, Arnaud, Brasiliense, Vitor, Audebert, Pierre, Pongilat, Remith, Gauthier, Magali, and Miomandre, Fabien

Subjects
GRAPHENE oxide, ENERGY storage, TETRAZINE, SUPERCAPACITORS, X-ray diffraction, RING formation (Chemistry), DIELS-Alder reaction
Abstract

A multi‐tetrazine compound tailored for grafting on graphene sheets has been designed and investigated. It is composed of hydrogen substituted tetrazines involved in inverse Diels‐Alder demand cycloaddition reactions for grafting and a central dialkoxytetrazine to confer redox properties to the final material. The successful incorporation of this compound in reduced graphene oxide was demonstrated by elemental analysis, XPS, Raman spectroscopy, AFM, SEM and XRD. Cyclic voltammetry shows the redox activity of the remaining central tetrazine unit in graphene and allows to assess the specific capacity of the material. A significant increase in the specific capacity was found compared to pristine graphene and another tetrazine model compound bearing only one grafting unit. This result was assigned to an increase in the specific area in relation to bridges created between graphene sheets, as evidenced by AFM and XRD. The performance in energy storage were assessed in symmetrical Swagelok cells confirming the high impact of the functionalization on capacitance values. [ABSTRACT FROM AUTHOR]

Published
2024
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7. Photophysical and Electrochemical Study of New Luminescent and Redox-Active Tetrazine Derivatives Grafted on Gold Nanoparticles

Author

Oliveira de Miranda, Livio, primary, Maillot, Baptiste, additional, Bosmi, Margarita, additional, Galmiche, Laurent, additional, Audibert, Jean-Frédéric, additional, Decorse, Philippe, additional, Brasiliense, Vitor, additional, Berthelier, Léa, additional, Bonnamour, Isabelle, additional, Darbost, Ulrich, additional, and Miomandre, Fabien, additional

Published
2023
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10. Single-Molecule Charge Transport through Positively Charged Electrostatic Anchors

Author

Chen, Hongliang, primary, Brasiliense, Vitor, additional, Mo, Jingshan, additional, Zhang, Long, additional, Jiao, Yang, additional, Chen, Zhu, additional, Jones, Leighton O., additional, He, Gen, additional, Guo, Qing-Hui, additional, Chen, Xiao-Yang, additional, Song, Bo, additional, Schatz, George C., additional, and Stoddart, J. Fraser, additional

Published
2021
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14. Local Surface Chemistry Dynamically Monitored by Quantitative Phase Microscopy.

Author

Brasiliense, Vitor, Audibert, Jean‐Frédéric, Wu, Tengfei, Tessier, Gilles, Berto, Pascal, and Miomandre, Fabien

Subjects
*STEREOLOGY, *SURFACE chemistry, *REFRACTIVE index, *QUANTITATIVE research, *DIAZONIUM compounds, *WAVEFRONT sensors
Abstract

Surface modification by photo grafting constitutes an interesting strategy to prepare functional surfaces. Precision applications, however, demand quantitative methods able to monitor and control the amount and distribution of surface modifications, which is hard to achieve, particularly in operando conditions. In this paper, a label‐free, cost‐effective, all‐optical method based on wavefront sensing which is able to quantitatively track the evolution of grafted layers in real‐time, is presented. By positioning a simple thin diffuser in the close vicinity of a camera, the thickness of grafted patterns is directly evaluated with sub‐nanometric sensitivity and diffraction‐limited lateral resolution. By performing an in‐depth kinetic analysis of the local modification of an inert substrate (glass cover slips) through photografting of arydiazonium salts, different growth regimes are characterized and several parameters are estimated, such as the grafting efficiency, density and the apparent refractive index distribution of the resulting grafted layers. Both focused and widefield‐grafting can be quantitatively monitored in real time, providing valuable guidelines to maximize functionalization efficiency. The association of a well‐characterized versatile photografting reaction with the proposed flexible and sensitive monitoring strategy enables functional surfaces to be prepared, and puts surface micro‐ to submicro‐structuration within the reach of most laboratories. [ABSTRACT FROM AUTHOR]

Published
2022
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15. Nanopipette‐based electrochemical SERS platforms: Using electrodeposition to produce versatile and adaptable plasmonic substrates.

Author

Brasiliense, Vitor, Park, Ji Eun, Chen, Zhu, Van Duyne, Richard P., and Schatz, George C.

Subjects
*ELECTROPLATING, *FRACTALS, *SURFACE potential, *SURFACE enhanced Raman effect, *SERS spectroscopy, *ALLOY plating
Abstract

A method for fabricating localized EC‐SERS probes based on nanopipettes and electrodeposition is described. Gold particles of fractal geometry with excellent SERS performance are produced, reliably and at low cost. By adapting the electrodeposition procedure, nanostructures of different sizes can be obtained, allowing the SERS platform to be tailored to many experimental configurations. In particular, by producing unique SERS platforms of dimensions comparable to the laser spot, quantitative comparison with electrochemical current is possible. By analyzing hundreds of samples, we thoroughly characterize the resulting geometry of the structures and their ability to enhance Raman signal, providing guidelines for the fabrication of optimized platforms. Control over the probes' surface potential also allows convenient modulation of surface‐analyte affinity and enable chemically unstable materials, such as Cu, to be reliably used. These are demonstrated by showing that Cu particles exposed to air can be easily re‐reduced, with no detriment in SERS performance. [ABSTRACT FROM AUTHOR]

Published
2021
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16. Opto-Electrochemical Methods for Imaging the Reactivity of Individual Nanoparticles

Author

Brasiliense, Vitor, STAR, ABES, Interfaces, Traitements, Organisation et Dynamique des Systèmes (ITODYS (UMR_7086)), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Université Sorbonne Paris Cité, Frédéric Kanoufi, Gilles Tessier, and Université Paris Diderot - Paris 7 (UPD7)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Holographie, Opto-Electrochemical Methods, [CHIM.OTHE] Chemical Sciences/Other, Holography, Nanoparticules, Nanoparticles, Nanoelectrochemistry, Nanoélectrochimie, Catalyse, [CHIM.OTHE]Chemical Sciences/Other, Méthodes Opto-électrochimiques, Catalysis
Abstract

A number of coupled optical and electrochemical single particle techniques are employed for investigating a variety of chemical systems at the level of individual objects.On the optical side, holography and visible spectroscopy are imbued with superlocalization principles pushing the applicability of these techniques down to sub-diffraction levels. Nanoelectrochemical techniques such as stochastic impacts and nanoelectrodes are used to complement this information, providing a much more complete characterization of the phenomena.It is shown that this dual optical and electrochemical single particle characterizationis actually crucial to understand complex nano chemical systems in loco. Starting frommodel reactions, such as Ag oxidation, the complexity of the studied phenomena and systems is progressively increased, as light is shed on transport phenomena, aggregation,as well as redox transformations and catalysis on complicated materials such as ill-defined transition metal (cobalt) oxides, Dans ce travail, plusieurs méthodes opto-électrochimiques ont été développées et appliquées à l’étude de systèmes chimiques à l’échelle de l’objet individuel. Du coté optique,l’holographie et la spectroscopie visible ont été associées à la super localisation pour pousser l’applicabilité de ces techniques au-delà de la limité imposée par la diffraction.Des techniques nanoélectrochimiques, comme les impacts stochastiques et l’utilisation de nanoelectrodes, complètent cette étude en renseignant sur la réactivité et sur les étapes de transfert d’électrons. Ces études couplées caractérisent ainsi les phénomènes chimiques de façon bien plus complète. Il est montré que cette caractérisation à la fois chimique et optique est en fait essentielle pour pouvoir comprendre le fonctionnement des systèmes nano chimiques in loco.En démarrant par des réactions modèle, comme l’oxydation de l’argent, la complexité des systèmes étudiés est progressivement augmentée, éclairant des phénomènes de transport,d’agrégation, ainsi que des transformation redox et de catalyse sur des matériaux complexes et mal définis tel que les oxydes de métaux de transition (cobalt)

Published
2017

30. Electrochemistry of single nanoparticles: general discussion

Author

Albrecht, Tim, primary, MacPherson, Julie, additional, Magnussen, Olaf, additional, Fermin, David, additional, Crooks, Richard, additional, Gooding, Justin, additional, Hersbach, Thom, additional, Kanoufi, Frederic, additional, Schuhmann, Wolfgang, additional, Bentley, Cameron, additional, Tao, Nongjian, additional, Mitra, Sushanta, additional, Krischer, Katharina, additional, Tschulik, Kristina, additional, Faez, Sanli, additional, Nogala, Wojciech, additional, Unwin, Patrick, additional, Long, Yitao, additional, Koper, Marc, additional, Tian, Zhongqun, additional, Alpuche-Aviles, Mario A., additional, White, Henry, additional, Brasiliense, Vitor, additional, Kranz, Christine, additional, Schmickler, Wolfgang, additional, Stevenson, Keith, additional, Jing, Chao, additional, and Edwards, Martin, additional

Published
2016
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31. Genericity of confined chemical garden patterns with regard to changes in the reactants

Author

Haudin, Florence, Brasiliense, Vitor, Cartwright, Julyan J.H.E., Brau, Fabian, De Wit, Anne, Haudin, Florence, Brasiliense, Vitor, Cartwright, Julyan J.H.E., Brau, Fabian, and De Wit, Anne

Abstract

The growth of chemical gardens is studied experimentally in a horizontal confined geometry when a solution of metallic salt is injected into an alkaline solution at a fixed flow rate. Various precipitate patterns are observed—spirals, flowers, worms or filaments—depending on the reactant concentrations. In order to determine the relative importance of the chemical nature of the reactants and physical processes in the pattern selection, we compare the structures obtained by performing the same experiment using different pairs of reactants of varying concentrations with cations of calcium, cobalt, copper, and nickel, and anions of silicate and carbonate. We show that although the transition zones between different patterns are not sharply defined, the morphological phase diagrams are similar in the various cases. We deduce that the nature of the chemical reactants is not a key factor for the pattern selection in the confined chemical gardens studied here and that the observed morphologies are generic patterns for precipitates possessing a given level of cohesiveness when grown under certain flow conditions., info:eu-repo/semantics/published

Published
2015

33. OperandoObservation of Molecular-Scale Manipulation Using Electrochemical Tip-Enhanced Raman Spectroscopy

Author

Chen, Xu, Brasiliense, Vitor, and Van Duyne, Richard P.

Abstract

Tip functionalization in scanning tunneling microscopy (STM) has become a routine strategy to improve the imaging resolution. Under ultrahigh vacuum and low-temperature conditions, individual molecule(s) can be transferred between the substrate and the tip when proper bias potential is applied, allowing for molecular-scale manipulation and controlled single-bond formation. However, little work related to tip functionalization in electrochemical (EC) environments has been carried out. To bridge that gap, this paper generalizes tip functionalization strategies from UHV conditions to the solid–liquid interfaces. Specifically, we demonstrate the bias-induced functionalization of an Ag tip with cobalt phthalocyanine molecules in EC-STM. Tip-enhanced Raman spectroscopy is employed for the operandodetection of the molecule(s) on the tip. We also show that the tip functionalization process may be reversed in some cases, regaining a pristine tip. The control over molecular transfer between the substrate and the tip not only provides guidance to avoid undesired tip modification in EC-STM experiments, but also offers the capability of molecular manipulation at the solid–liquid interface.

Published
2018
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34. Heptazine derivative bearing tetrazine capped arms: A new fluorescent and redox platform for reduced graphene oxide functionalization.

Author

Marin, Clarisse, Dalloz, Enzo, Bosmi, Margarita, Brasiliense, Vitor, Galmiche, Laurent, Allain, Clémence, Miomandre, Fabien, and Audebert, Pierre

Subjects
*GRAPHENE oxide, *TETRAZINE, *OXIDATION-reduction reaction, *ENERGY transfer, *MANUFACTURING processes
Abstract

We have synthesized the first example of a heptazine molecule bearing three arms, each of them functionalized by a tetrazine at the end. This new original molecule is redox active and fluorescent, benefiting from the energy transfer between the strongly absorbing heptazine core and the emitting tetrazine units. This molecule has been used to functionalize reduced graphene oxide by an easy process resulting in a material able to store charges by a dual faradaic and capacitive mechanism. [Display omitted] [ABSTRACT FROM AUTHOR]

Published
2024
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35. Opto-electrochemical In Situ Monitoring of the Cathodic Formation of Single Cobalt Nanoparticles.

Author

Brasiliense V, Clausmeyer J, Dauphin AL, Noël JM, Berto P, Tessier G, Schuhmann W, and Kanoufi F

Abstract

Single-particle electrochemistry at a nanoelectrode is explored by dark-field optical microscopy. The analysis of the scattered light allows in situ dynamic monitoring of the electrodeposition of single cobalt nanoparticles down to a radius of 65 nm. Larger sub-micrometer particles are directly sized optically by super-localization of the edges and the scattered light contains complementary information concerning the particle redox chemistry. This opto-electrochemical approach is used to derive mechanistic insights about electrocatalysis that are not accessible from single-particle electrochemistry., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Published
2017
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