Séminaire Riccardo Ferrando « Structural transformations of metallic NP and nanoalloys… »

Séminaire :
«Structural transformations of metallic nanoparticles and nanoalloys. How simulations can shed light on experiments ? » 
le mardi 4 février à 11h en salle Olivier Kahn à l’ICMMO (Bât. 410, Université Paris-Saclay)
Riccardo Ferrando
Dipartimento di Fisica, Università di Genova, Via Dodecaneso 33, Genova, Italy

The experimentally observed nanoparticle structures are often the result of a competition between kinetic effects and equilibration. Here we consider different types of out-of-equilibrium processes, ranging from temperature-dependent solid-solid transformations [1-3], to growth processes in the gas phase [4-7], to coalescence of preformed clusters [8]. The systems considered here are pure Au nanoparticles [1,4,8], and several nanoalloys (AgPt [2], AuCo, AgCu, AgNi [3], AgAu [5], PtPd [6], AuFe [7]). Kinetic effects are studied by classical molecular dynamics, whereas equilibrium properties are determined by global optimization searches, harmonic thermodynamics calculations and DFT calculations [9,10]. We show how simulation results can help in interpreting complex processes in different experiments [1,2,4-7].

[1] D.M. Foster, R. Ferrando, R.E. Palmer , Nature Communications 9, 1323 (2018)
[2] J. Pirart, A. Front, D. Rapetti, P. Andreazza, C. Andreazza, C. Mottet, R. Ferrando, Nature Communications, 10, 1982 (2019).
[3] D. Nelli, R. Ferrando, Nanoscale 11, 13040 (2019)
[4] D.M. Wells, G. Rossi. R. Ferrando, R.E. Palmer, Nanoscale, 7, 6498 (2015)
[5] T.-W. Liao, A. Yadav, K.-J. Hu, J. van der Tol, S. Cosentino, F. D’Acapito, R.E. Palmer, C. Lenardi, R. Ferrando, D. Grandjean, P. Lievens, Nanoscale 10, 6684 (2018)
[6] D. Nelli, R. Ferrando, C. Minnai, in preparation (2020)
[7] J. Vernieres, S. Steinhauer, J. Zhao, P. Grammatikopoulos, R. Ferrando, K. Nordlund, F. Djurabekova, M. Sowwan, Advanced Science 1900447 (2019)
[8] D. Nelli, Z. Wang, R.E. Palmer, R. Ferrando, submitted (2020)
[9] J.-P. Palomares-Baez, E. Panizon, R. Ferrando, Nano Letters,  17, 5394 (2017)
[10] D. Rapetti, R. Ferrando, J. Alloys Compd. 779, 582 (2019).

25e Journées du Groupe Français de Spectroscopie Vibrationelle 2019

Cher(e)s collègues,

Nous avons le plaisir de vous informer que les 25ièmes journées du Groupe Français de Spectroscopie Vibrationnelle (GFSV) se dérouleront du 13 mai au 15 mai 2019 au centre de congrès Valpré, situé à Ecully, dans la métropole de Lyon. Ces journées ont pour but de rassembler la communauté scientifique travaillant dans le domaine de la spectroscopie vibrationnelle photonique, et d’échanger sur le plan fondamental et appliqué autour de thématiques.

Vous pourrez également profiter de Lyon à travers une visite culturelle et un repas convivial à la brasserie Georges !

Dès à présent, nous vous invitons à soumettre un résumé afin de présenter vos travaux de recherche. Le site est ouvert aux soumissions de résumés et aux inscriptions.

Nous attirons votre attention sur notre souhait d’assurer suffisamment de présentations orales pour les doctorants, qui bénéficient également d’un tarif très avantageux.

Nous vous attendons nombreux à ces journées !

L’équipe d’organisation (contact : Guilhem SIMON)

Séminaire présenté par C. Klinke

Two-dimensional nanostructures: Synthesis and optoelectronic transport

In my talk I will briefly review the fields of my research and then, I will show that two-dimensional colloidal nanosheets represent very attractive optoelectronic materials. They combine good lateral conductivity with solution-processability and geometry-tunable electronic properties. The formation of ordered and densely packed surface layers of amphiphilic ligand molecules on certain crystal facets can drive the normally isotropic into a two-dimensional crystal growth, resulting in semiconducting nanosheets. The electronic confinement in height allows tuning the effective bandgap of the materials.
I will present the syntheses of the materials and the analyses of the electrical transport through these materials in field-effect transistors, solar cells, and spintronic devices. It turns out that the electronic confinement allows for an optimization of their performances.

Pr. Christian KLINKE
Institute of Physical Chemistry, University of Hamburg, Germany
& Chemistry Department, Swansea University, United Kingdom

Conférences dans le cadre de laboratoires associés « TrEnemalFC » avec le soutien d’OPUS

Dans le cadre du Laboratoire International Associé CNRS « TrEnemalFC » entre le Palace Museum (Beijing, Chine) avec le soutien d’OPUS
et MONARIS UMR8233 SU, CRCAO, UMR8155 Collège de France – EPHE – Université Paris 7 Diderot, ICT EA 337, Université Paris 7 Diderot, CAK, UMR8560 – EHESS – CNRS – MNHN, CEMES UPR8011 et différents musées français (Beaux-arts de Limoges, Compagnies des Indes de Lorient, Château de Versailles, Cité de la Céramique Sèvres & Limoges, des Arts décoratifs Paris, des Arts asiatiques – Guimet).

2 conférences se tiendront sur le 25 juin 2018 sur le Campus P. et M. Curie (salle 101, Tour 32, 1er étage, couloir 32-42 (UFR CHIMIE).

M. Yang Yong « Le Motif du poisson Makara ou la nouvelle datation des émaux cloisonnés des Ming 1368-1644 ».
Mme Han Qian « La disposition des fleurs aux Palais des Qing 1644-1911 »

Venez nombreux

 

Séminaire présenté par Pr. Maurice Brogly

Vendredi 22 Juin 2018 à 15h45 – 16h45

Séminaire présenté par Pr. Maurice BROGLY
LPIM, Université de Haute Alsace, Mulhouse
Adsorption, structuration and crystallisation of adhesion promoters and polymer thin films on metal substrates: analysis by PM-IRRAS and AFM

This presentation will give an overview of the laboratory LPIM’s research activities related to thin polymer films at interfaces. The presented works will focus on the understanding on how polymers (either homopolymers or copolymers) organize in thin films and how this organization can be directed adhesion promoters used to control the surface chemistry of the metal substrate. Various polymers and copolymers were adsorbed by spin-coating on metal substrates. The surface chemistry of the substrates was controlled by chemical grafting of adhesion promoters (coupling agents). The influence of the hydrophilic or hydrophobic nature of the substrate on the organization and structuration of polymers and copolymers of different compositions was then studied.
Characterization of thin films of copolymers requires the use of specific characterization techniques. Polarization-Modulation Infrared Reflection Absorption Spectroscopy (PM- IRRAS) spectroscopy is and innovative and original vibrational spectroscopy that was used for « in situ » reflectivity experiments to characterize thin films of polymers and copolymers deposited on reflective substrates. Due to the polarization modulation of the incident IR wave, its reflection at the interface according to surface selection rules increases the sensitivity of the spectral response, allowing determination of molecular orientation and structuring effects. Atomic Force Microscopy (AFM) analyses were also performed on the same thin films, in order to access the surface morphology and to distinguish the amorphous and crystalline phases.
Chains orientations and conformations as well as surface morphologies were thus characterized in order to understand the competition between polymer/polymer and polymer/substrate interactions, which will have a direct effect on the crystallization. This was explained by changes in the balance of polymer/polymer vs polymer/substrate interactions. Substrate surface chemistry alters the balance between these interactions significantly. As an example, in the case of amphiphilic block copolymers, an hydrophilic substrate favors the crystallization of the polar block whereas an hydrophobic substrate will favor the non-polar block crystallization. The modification of the crystalline phase content, morphology and molecular orientation of the crystalline structures of the adsorbed films reflects the strong competition between interfacial forces and intra and intermolecular forces.