locked59 Intranet

 

 

Nanocarbon Design

C. Ewels, J.-L. Duvail, M. Bayle, B. Humbert

The design of new families of nanocarbon materials, from bottom-up approaches (notably for carbon nanorings, CPPs, azafullerenes, and hybrid systems), to chemical and structural modification of existing nanocarbons, such as selective filling of collapsed carbon nanotubes cavities. We are also interested in carbon nanostructure formation processes (such as fullerenes in space), and ways that different nanostructures can be modified (e.g. dislocation cores).

As well as the nanocarbons themselves, we are innovating in ways that nanocarbons can be used as templates, creating previously unknown material phases due to nanoconfinement (for example inside carbon nanotubes).

We rely strongly on computational modelling tools, and local, national and international collaborations.

 nanocarbon 
Other people involved : 
A. Impellizzeri (), Y. Tanuma ().
Keywords : 
Nanocarbon, Fullerene, CPP, Nanotube, Nanoconfinement.

  Projects :

Using density functional theory with van der Waals (vdW) corrections, we study the collapse of free-standing single-walled carbon nanotubes (also called “dogbone” nanotubes). Their thermodynamic stability is strongly influenced by the initial stacking sequence, with lateral shear allowing registry change with turbostratic stacking predominant. The electronic structure of collapsed zigzag and armchair carbon nanotubes is investigated, demonstrating sensitivity to the lattice registry. The opening of small (meV) band gaps is shown for both armchair and zigzag collapsed nanotubes, arising from quantum confinement and charge transfer between the bilayer graphenelike central region and nanotubelike edges. Different scaling rules for the band gaps of collapsed carbon nanotubes are obtained as a function of their widths taking stacking and chirality into account. We reconcile a complete understanding of electronic properties in these deformed tubes with literature theoretical and experimental results, suggesting collapsed nanotubes can be promising candidates as conductive nanoribbons in electronic and spintronic device applications.

 

Intense Raman D Band without Disorder in Flattened Carbon Nanotubes.
E. Picheau, A. Impellizzeri, D. Rybkovskiy, M. Bayle, J.-Y. Mevellec, F. Hof, H. Saadaoui, L. Noé, A. Cefas Torres Dias, J.-L. Duvail, M. Monthioux, B. Humbert, P. Puech, C. P. Ewels, and A. Pénicaud, ACS Nano 15 (1), 596-603 (2021)

Stacking- and chirality-dependent collapse of single-walled carbon nanotubes: A large-scale density-functional study
A. Impellizzeri, P. Briddon, C. P. Ewels, Phys. Rev. B 100 (11) 115410 (2019)

Polyiodide structures in thin single-walled carbon nanotubes: A large-scale density-functional study
D. V. Rybkovskiy, A. Impellizzeri, E. Obractsova, C. P. Ewels, Carbon, 142, 123-130 (2018)

Même si les nanotubes de carbone possèdent un énorme potentiel pour révolutionner plusieurs champs scientifiques au cours du 21e siècle, leurs applications dans le domaine nanoélectronique sont bloquées depuis deux décennies. Il est en effet impossible à ce jour de produire des tubes de diamètre et de structure électronique bien contrôlés. Dans le PSR NEWTUBE nous proposons une approche en rupture pour résoudre ce problème. Elle vise à utiliser une stratégie innovante «bottom-up» qui permettra de produire une nouvelle famille de matériaux de type nanotube. Par analogie aux polymères conjugués, nous proposons de relier ensemble de petits anneaux de nanocarbone (naonocerceaux ou cycloparaphénylènes) par un procédé de polymérisation contrôlé (templated polymerization). Cette approche permettra ainsi de créer nouvelle famille de nanotubes composée de chaînes de nano-anneaux connectés. Ce projet de modélisation s'appuie sur des expertises complémentaires en nanomatériaux des composés carbonés (IMN) et en modélisation moléculaire organique (CEISAM), pour concevoir in-silico ces nouveaux nanomatériaux. Ils représentent une toute nouvelle classe de matériaux dont le comportement pourra être contrôlé à l'aide d'outils développés pour la chimie de synthèse. Grâce aux outils de la simulation, nous prédirons leurs propriétés électroniques et optiques et pourrons ainsi guider nos collègues expérimentateurs vers les systèmes les plus prometteurs

  • PHC Proteus 2021 (CPP-Fulleradicals) (2021-2022)

A major handicap towards the exploitation of radicals is their inherent instability. In the paramagnetic azafullerenyl radical C59N., the unpaired electron is strongly localized next to the nitrogen atom, which induces dimerization to diamagnetic bis(azafullerene), (C59N)2. We have developed an innovative radical shielding approach based on supramolecular complexation, exploiting the protection offered by a [10]cycloparaphenylene ([10]CPP) nanobelt encircling the C59N. radical. Photoinduced radical generation is increased by a factor of 300. The EPR signal showing characteristic 14N hyperfine splitting of C59N.⊂ [10]CPP was traced even after several weeks, which corresponds to a lifetime increase of >108. The proposed approach can be generalized by tuning the diameter of the employed nanobelts, opening new avenues for the design and exploitation of radical fullerenes.
We will use [10]CPP with different azafullerene species to achieve desired assembly and radical stabilisation, targeting qubits, organic magnets and superconductors. We intend to open up new physics emerging from the possibility to tailor localised vs delocalised radical states. Our approach allows for tailor-made organic magnets and superconductors, and opens new physics beyond the conventional fullerene physics emerging from the intertwining of localised and extended states. The purpose of this collaborative project is to study such localised and extended states in various assemblies from the theoretical (DFT computations performed at IMN) as well as experimental (magnetic resonance techniques at IJS) point of view.

 

Long-lived azafullerenyl radical stabilized by supramolecular shielding with a [10]cycloparaphenylene
A. Stergiou, J. Rio, J. H. Griwatz, D. Arcon, H. A. Wegner, C. P. Ewels, N. Tagmatarchis
 Angewandte Chimie International Edition, 58 (49), 17745-17750 (2019)
ChemistryViews magazine article and YouTube video on this work.

Electronic communication between two [10]cycloparaphenylenes and bisazafullerene (C59N)2 induced by cooperative complexation
J. Rio, S. Beeck, G. Rotas, S. Ahles, D. Jacquemin, N. Tagmatarchis, C. Ewels, H. A. Wegner
Angewandte Chimie International Edition, 57 (23), 6930-6934 (2018)
and in German, Angewandte Chemie 130 (23), 7046-7050 (2018)

  •  CNRS Momentum (F.Hof CRPP, 2018-2020)

The project is in collaboration with CRPP Bordeaux, developing a totally new way to use graphite intercalation processes to produce charged graphene layers in solution.  These layers will be stabilized in organic media under exclusion of oxygen/water (C. Valles, et al., J. Am. Chem. Soc. 2008), and can serve as a chemical platform to graft metal nanoparticle onto the carbon framework, (F.  Hof et al., Chem Eur. J., 2018).  Related composite materials have been found to be excellent electrocatalysts (F. Hof et al., Chem Eur. J. 2017).

 Collaborations:

Giessen, Germany – Hermann Wegner
Athens, Greece – Nikos Tagmatarchis
Ljubljana, Slovenie – Denis Arcon
CEMES Toulouse – Marc Monthious
CRPP Bordeaux – Alain Penicaud, Ferdinand Hof
CEISAM Nantes – Denis Jacquemin
Loughborough, UK - Kenny Jolley
Newcastle, UK – Patrick Briddon
Moscow – Dmitry Rybovskiiy
Toyo University, Kawagoe - Toru Maekawa
(and others)

Downloadhttp://bigtheme.net/joomla Joomla Templates