A5050753683- Electrochemical Analysis and Applications
- Electrochemical sensors and biosensors
- Advanced biosensing and bioanalysis techniques
- Force Microscopy Techniques and Applications
- Advanced Electron Microscopy Techniques and Applications
- Gold and Silver Nanoparticles Synthesis and Applications
- Molecular Junctions and Nanostructures
- Electrocatalysts for Energy Conversion
- Conducting polymers and applications
- Electron and X-Ray Spectroscopy Techniques
- Nanofabrication and Lithography Techniques
- Luminescence and Fluorescent Materials
- Analytical Chemistry and Sensors
- Chemical Synthesis and Reactions
- Slime Mold and Myxomycetes Research
- Photochromic and Fluorescence Chemistry
- Spectroscopy and Quantum Chemical Studies
- Copper-based nanomaterials and applications
- Recycling and Waste Management Techniques
- Plant and Biological Electrophysiology Studies
- Near-Field Optical Microscopy
- Polymer Surface Interaction Studies
- Polyoxometalates: Synthesis and Applications
- Advanced Fluorescence Microscopy Techniques
- nanoparticles nucleation surface interactions
Centre National de la Recherche Scientifique
2015-2024
Université Paris-Saclay
2021-2024
École Normale Supérieure Paris-Saclay
2023
Laboratoire de Photophysique et Photochimie Supramoléculaires et Macromoléculaires
2023
Northwestern University
2018-2022
École Normale Supérieure - PSL
2021
Université Paris Cité
2015-2020
Interfaces Traitements Organisation et Dynamique des Systèmes
2015-2020
Délégation Ile-de-France Villejuif
2016-2020
Canadian Nautical Research Society
2020
Electrochemical (EC) impacts of single nanoparticles (NPs) on an ultramicroelectrode are coupled with optics to identify chemical processes at the level individual NPs. While EC signals characterize charge transfer process, optical monitoring gives a complementary picture transport and transformation This is illustrated in case electrodissolution Ag In simplest case, optically monitored dissolution NPs synchronized spikes. Optics then validates situ concept nanoimpacts for sizing counting...
The charge transport in single-molecule junctions depends critically on the chemical identity of anchor groups that are used to connect molecular wires electrodes. In this research, we report a new anchoring strategy, called electrostatic anchor, formed through efficient Coulombic interaction between gold electrodes and positively charged pyridinium terminal groups. Our results show these serve as anchors forming robust gold–molecule–gold junctions. We have also observed binary switching...
Transport-reaction processes at individual Ag nanoparticles (NPs) are studied using electrochemistry coupled with in situ 3D light scattering microscopy. Electrochemistry is used to trigger a (i) diffusiophoretic transport mode capable of accelerating and preconcentrating NPs toward an electrode (ii) subsequent diffusion-controlled oxidation NPs. Individual NP dissolution rate, analyzed optical modeling, suggests the intervention insoluble products. New insights into diverse behaviors...
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 electrodeposition single cobalt nanoparticles down to radius 65 nm. Larger sub‐micrometer particles are directly sized optically super‐localization edges and contains complementary information concerning particle redox chemistry. This opto‐electrochemical approach used derive mechanistic insights about...
The growth of chemical gardens is studied experimentally in a horizontal confined geometry when solution metallic salt injected into an alkaline at fixed flow rate. Various precipitate patterns are observed-spirals, flowers, worms or filaments-depending on the reactant concentrations. In order to determine relative importance nature reactants and physical processes pattern selection, we compare structures obtained by performing same experiment using different pairs varying concentrations...
Abstract Single nanoparticle (NP) electrochemistry detection at a micro liquid|liquid interface (LLI) is exploited using the catalyzed oxygen reduction reaction (ORR). In this way, current spikes reminiscent of nanoimpacts were recorded, which corresponded to electrocatalytic enhancement ORR by Pt NPs. The nature LLI allows exploration new phenomena in single NP electrochemistry. recorded impacts result from bipolar occurring straddling LLI. O 2 takes place aqueous phase, while ferrocene...
ConspectusInterest in nanoparticles has vigorously increased over the last 20 years as more and studies show how their use can potentially revolutionize science technology. Their applications span many different academically industrially relevant fields such catalysis, materials science, health, etc. Until past decade, however, nanoparticle mostly relied on ensemble studies, thus leaving aside chemical heterogeneity at single particle level. Over few years, powerful new tools appeared to...
By partially overcoming the diffraction limit, superlocalization techniques have extended applicability of optical down to nanometer size-range. Herein, cobalt oxide-based nanoparticles are electrochemically grown onto carbon nanoelectrodes and their individual catalytic properties evaluated through a combined electrochemical-optical approach. Using dark-field white light illumination, edges applied quantify changes in particle size during electrochemical activation with 20 nm precision. It...
The plasmon-driven chemistry of ferri-/ferrocyanide ions inside surface-enhanced Raman spectroscopy (SERS) active hot spots associated with gold nanoparticle oligomers is studied continuous wave (CW) pump–probe SERS. By comparing solution-phase normal spectra, the characteristic spectral variations observed upon 532 nm optical pumping can be attributed to an oxidation process that occurs on surface species followed by desorption oxidized from nanoparticles. Interrogating processes over a...
Although extremely sensitive, electrical measurements are essentially unable to discriminate complex chemical events involving individual nanoparticles. The coupling of electrochemistry dark field imaging and spectroscopy allows the triggering electrodissolution an ensemble Ag nanoparticles (by electrochemistry) inference both oxidation dissolution processes spectroscopy) at level a single nanoparticle. Besides inspection process from optical scattering intensity, adding reveals changes...
The polyoxomolybdate hybrid TBA3[PMo11O39{Sn(C6H4)C≡C(C6H4)N2}] KMoSn[N2+] was prepared through Sonogashira-type coupling between TBA4[PMo11O39{Sn(C6H4)I}] KMoSn[I] and an excess of 3,3-diethyl-1-(4-ethynylphenyl)triaz-1-ene bearing a protected diazonium function, followed by its deprotection the addition trifluoroacetic acid (TFA). This enlarges family organic–inorganic polyoxomolybdate-based hybrids, which has been far less investigated than their related polyoxotungstates. function allows...
Sushanta Mitra opened a general discussion of the paper by Keith Stevenson: For nanoparticle impact study, if there are surface charges present on nanoparticle, will be any screening effect? The reason for such an issue is that often they modeled as particle-collector (Happel
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 substrate tip when proper bias potential is applied, allowing for molecular-scale manipulation controlled single-bond formation. However, little work related electrochemical (EC) environments been carried out. To bridge that gap, this paper generalizes strategies...
When narrowly distributed silver nanoparticles (NPs) are functionalized by dodecanethiol, they acquire the ability to self-organize in organic solvents into 3D supercrystals (SCs). The NP surface chemistry is shown introduce a light-driven thermomigration effect, thermophoresis. Using laser beam heat NPs and generate steep thermal gradients, migration effect triggered dynamically, leading tailored structures with high density of plasmonic hot spots. This work describes how manipulate spots...
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 at low cost. By adapting the procedure, nanostructures different sizes can be obtained, allowing platform to tailored many experimental configurations. In particular, by producing unique platforms dimensions comparable laser spot, quantitative comparison electrochemical current possible....
Abstract Single nanoparticle (NP) electrochemistry detection at a micro liquid|liquid interface (LLI) is exploited using the catalyzed oxygen reduction reaction (ORR). In this way, current spikes reminiscent of nanoimpacts were recorded, which corresponded to electrocatalytic enhancement ORR by Pt NPs. The nature LLI allows exploration new phenomena in single NP electrochemistry. recorded impacts result from bipolar occurring straddling LLI. O 2 takes place aqueous phase, while ferrocene...
Most protocols developed to synthesize nanoparticles (NPs) and control their shape are inspired from nucleation growth theories. However, rationalize the mechanisms of shape-selective synthesis NPs, experimental strategies allowing probe in situ NPs needed. Herein, metal Au or Ag produced by reaction a metallic ion precursor with reversible redox reducer. The process is explored an oxidative electrosynthesis strategy using sacrificial ultramicroelectrode both trigger generation local...
Abstract By scrutinizing the trajectory of individual nanoparticles (NPs) in solution, NP tracking analysis (NTA) allows sizing NPs and providing meaningful complementary information to single electrochemistry. Herein, a model is developed extend NTA allow dynamic analyze kinetics growth solution. Interpreting trajectories as scaled Brownian motion, Monte Carlo simulations produce stochastic growing (under diffusion‐controlled growth). These are grounds for determining strategy estimate...
Surface modification by photo grafting constitutes an interesting strategy to prepare functional surfaces. Precision applications, however, demand quantitative methods able monitor and control the amount distribution of surface modifications, which is hard achieve, particularly in operando conditions. In this paper, a label-free, cost-effective, all-optical method based on wavefront sensing quantitatively track evolution grafted layers real-time, presented. By positioning simple thin...
New tetrazine derivatives able to be grafted on gold surfaces have been synthesized with either disulfide or thioctic anchoring units, and their electrochemical photophysical properties are investigated in solution. In parallel, nanoparticles electrodeposited indium tin oxide then functionalized by the compounds. The modified characterized X-ray photoelectron spectroscopy a focus influence of deposition potential immersion time. Tetrazines remain fully electroactive emissive once grafted....
High resolution and quantitative surface modification through photografting is a highly desirable strategy towards the preparation of smart surfaces, enabling chemical functions to be precisely located onto specific regions inert surfaces. Although promising, mechanisms leading direct (without use any additive) photoactivation diazonium salts using visible wavelengths are poorly understood, precluding generalization popular diazonium-based electrografting strategies into high ones. In this...
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 a central dialkoxytetrazine to confer redox properties the final material. The successful incorporation this reduced oxide was demonstrated by elemental analysis, XPS, Raman spectroscopy, AFM, SEM XRD. Cyclic voltammetry shows activity remaining tetrazine unit allows...
Abstract Die Elektrochemie einzelner Partikel auf einer Nanoelektrode wird mittels optischer Dunkelfeldmikroskopie untersucht. Betrachtung des gestreuten Lichts macht es möglich, die elektrochemische Abscheidung Cobaltnanopartikel mit Radien bis hinunter zu 65 nm in situ verfolgen. Dimensionen von größeren Submikropartikeln können durch Superlokalisierung der Partikelgrenzen bestimmt werden. Zusätzlich enthält das gestreute Licht ergänzende Informationen über komplexe Redoxchemie. Mit...
A nanometrology approach is used to quantify and control the photografting of different aryl radicals. In spite grafting kinetics spanning several orders magnitude, volume grafted patterns can be controlled with attoliter precision.