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Introduction to vibrational spectroscopies
Auteur(s): Bantignies J.-L.
Conférence invité: French-Brazilian spring school on ‘‘Raman spectroscopy of carbon nanomaterials’’ (Montpellier, FR, 2018-04-17)
Résumé: Introduction to vibrational spectroscopies
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Enhancing the Infrared Response of Carbon Nanotubes From Dye Interactions, Chemontubes
Auteur(s): Bantignies J.-L., Alvarez L., Belhboub A., Hermet P., Le Parc R.
Conference: CHEMONTUBES (Biarritz, FR, 2018-04-23)
Ref HAL: hal-01949731_v1
Exporter : BibTex | endNote
Résumé: Middle infrared response on a carbon nanotube is very weak because this homonuclear allotrope of carbon does not bear permanent dipoles. Nevertheless, a significant number of infrared phonons are predicted by the group theory. Encapsulating molecules inside nanotubes (called hybrid nanotubes in the following) is a common strategy to add new functionalities. The one-dimensional nature of single-walled carbon nanotubes (SWCNT) internal channels has been exploited here to induce a molecular order and specific interactions which are dependent of the size of the nano container (figure).Here we report the discovery of a strong dependence on the infrared response of the hybrid nanotube due to confinement effect when dimethylquaterthiophenes are encapsulated inside SWCNTs1. Results are compared to experiments performed on nanotubes where dyes are π-stacked at the outer surface. Surprisingly, the confinement properties lead to an exaltation of the infrared absorption response in the carbon nanotubes from dye molecule interactions. Thanks to the comparison between the experimental investigations and DFT calculations, we elucidate the origin of the large enhancement of this infrared absorption and demonstrate that interactions between conjugated oligomers and nanotubes can be probed.
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Introduction à la spectroscopie EXAFS
Auteur(s): Bantignies J.-L.
Conférence invité: Ecole d'initiation à la spectroscopie d'absorption des rayons X (Montpellier, FR, 2018-06-11)
Résumé: Introduction à la spectroscopie EXAFS
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« Introduction aux spectroscopies vibrationnelles infrarouge et Raman »
Auteur(s): Bantignies J.-L.
Conférence invité: Rencontre PAC chimie Balard (Montpellier, FR, 2018-09-13)
Résumé: « Introduction aux spectroscopies vibrationnelles infrarouge et Raman »
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Infrared spectrscopy : theory and applications
Auteur(s): Bantignies J.-L.
Conférence invité: Workshop Franco-Maghrébin sur les Spectroscopies Vibrationnelles IR et Raman (Hammamet, TN, 2018-11-19)
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Endohedral confinement of dies inside carbon nanotubes : key factor for charge transfer modulation
Auteur(s): Bantignies J.-L.
Conférence invité: ILL and ESS European Users Meeting (Grenoble, FR, 2018-10-10)
Ref HAL: hal-01945783_v1
Exporter : BibTex | endNote
Résumé: Encapsulating molecules inside nanotubes (called hybrid nanotubes in the following) is a common strategy to add new functionalities to the nanocontainer. The one-dimensional nature of single-walled carbon nanotubes (SWCNT) internal channels is exploited here to induce a molecular order and specific interactions which are dependent of the size of the nano container (figure 1). I present here the study of the relation between structural, vibrational and electronic properties of hybrid nanotubes encapsulating dyes. Dimethyl-quarterthiophene (4TCH3) encapsulated inside single-walled carbon nanotubes is studied by inelastic neutron scattering. The results reveal specific dynamics of the 4TCH3 modes characterized in particular by a large sensitivity in the low frequency domain of the methyl libration to the confinement. DFT based calculations consistently describe the observed phenomena and give insights on the structure of the hybrid nanotubes at low temperature where molecules preferentially interact with the nanotube wall. We evidence also by means of Raman spectroscopy and transmission electron microscopy that the supramolecular organizations of the confined oligothiophenes depend on the nanocontainer size. Charge transfer between the dyes and the nanocontainer is shown. A strong dependence on the infrared response of the hybrid nanotube due to confinement effect is finally investigated. The results are compared to experiments performed on nanotubes where dyes are π-stacked at the outer surface. Surprisingly, the confinement properties lead to an exaltation of the infrared absorption response in the carbon nanotubes from dye molecule interactions. Thanks to the comparison between the experimental investigations and DFT calculations, we elucidate the origin of the large enhancement of this infrared absorption.
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