SUPRAMOLECULAR ORGANIZATION OF pi-CONJUGATED MOLECULES MONITORED BY SINGLE-WALLED CARBON NANOTUBES
Résumé
New 1D hybrid nano-systems are elaborated with photo-active -conjugated molecules (PAM) either encapsulated into the hollow core of single-wall carbon nanotubes or non-covalently functionalized at their outer surface. The physical properties can be tuned by modifying the structural properties, providing practical routes to fit different requirements for potential applications. In this study, we report results obtained by functionalizing single wall carbon nanotubes with quathertiophene (4T) and phathlocyanine (MPc) molecules. The structural properties are investigated mainly by x-ray diffraction and/or Transmission Electron Microscopy and Raman spectroscopy. We evidence that the supramolecular organizations of confined oligothiophenes (from 1 to 3 chains into a nanotube section) depend on the nanocontainer size whereas phthalocyanine encapsulation leads the formation of a 1D-phase for which the angle between the molecule ring and the nanotubes axis is close to 32°. Confined MPc molecules display Raman spectra hardly altered with respect to the bulk phase, suggesting a rather weak interaction with the tubes. In contrast, the vibrational properties of the molecules functionalized at the outer surface of tubes display important modifications. We assume a significant curvature of the phthalocyanine induced by the interaction with the tube walls and a change of the central atom position within the molecular ring, in good agreement with our DFT calculations.