Les nanotubes de carbone monofeuilltes (SWCNT) sont fonctionnalisés avec des nanoparticules d'hexacyanoferrate de cuivre (CuHCF) pour préparer des substrats solides pour la sorption des ions de césium (Cs +) des écoulements de liquide. La haute résistance mécanique et la grande conductivité électrique des SWCNT sont associées à la capacité des nanoparticules de CuHCF à complexer sélectivement les ions Cs + afin de réaliser des buckypapers de type membrane présentant une capacité de charge élevée du césium. Les matériaux sont soigneusement caractérisés en utilisant la microscopie électronique, la diffusion Raman, la spectroscopie de photoélectrons X et les analyses thermogravimétriques. Les isothermes de sorption de Cs sont portées après avoir mesuré la concentration en Cs + par chromatographie ionique en phase liquide dans la solution avant et après l'exposition aux matériaux. On trouve que la capacité totale de sorption du matériau atteint 230 mg.g-1, et qu'environ un tiers du Cs sorbé (80 mg.g-1) est sélectivement complexé dans les nanoparticules de CuHCF greffées sur SWCNTs. Les valeurs ouvrent des perspectives intéressantes dans l'intégration de tels matériaux dans des dispositifs de sorption et de désorption contrôlée de ces ions.

Single-walled carbon nanotubes (SWCNTs) are functionalized with copper hexacyanoferrate (CuHCF) nanoparticles to prepare solid substrates for the sorption of cesium ions (Cs+) from liquid outflows. The high mechanical resistance and large electrical conductivity of SWCNTs are associated to the ability of CuHCF nanoparticles to selectively complex Cs+ ions in order to achieve membrane-like buckypapers presenting high loading capacity of cesium. The materials are thoroughly characterized using electron microscopy, Raman scattering, X-ray photoelectron spectroscopy and thermogravimetric analyses. Cs sorption isotherms are plotted after having measured the Cs+ concentration by liquid phase ionic chromatography in the solution before and after exposure to the materials. It is found that the total sorption capacity of the material reaches 230 mg.g-1, and that about one third of the sorbed Cs (80 mg.g-1) is selectively complexed in the CuHCF nanoparticles grafted on SWCNTs.1 These high values open interesting outlooks in the integration of such materials in devices for the controlled sorption and desorption of these ions.

Opto-electronic properties of single-walled carbon nanotubes can be significantly modified by chromophore confinement into their hollow core. This presentation deals with quaterthiophene derivatives encapsulated into nanotubes displaying different diameter distributions. We show that the supramolecular organizations of the confined chromophores depend on the nanocontainer size. The Raman radial breathing mode frequency is monitored by both the number of confined molecules into a nanotube section and the competition between dye/dye and dye/tube wall interactions. The confinement properties lead also to an exaltation of the infrared absorption response1 in single-walled carbon nanotubes from dye molecule interactions due to a symmetry breaking, allowing us, thanks to the complementarity of DFT calculations and experimental IR investigations to study interactions between both subsystems. Significant electron transfer from the confined molecules to the nanotubes is also reported from Raman investigations. This charge transfer leads to an important enhancement of the photoluminescence intensity by a factor of nearly five depending on the tube diameter. In addition, close to the molecule resonance, the magnitude of the Raman G-band shifts is modified and the intensity loss is amplified, indicating a photo-induced electron transfer. Results are discussed in the frame of electron-phonon coupling. Thus, confinement species into nanotubes allow moving the Fermi level and consequently to monitor their opto-electronic properties.

The rise of efficient extraction techniques triggered a renewal of interest in semiconducting carbon nanotubes (s-SWNT) research. It represents a great interest for optoelectronics, with outstanding properties in field-effect transistor, and s-SWNT ability to efficiently emit light in the near-IR range. In particular, polyfluorene (PFO) wrapped s‑SWNT (s-SWNT@PFO) display strong photoluminescence, and could be coupled with photonic devices such as microring resonators [1,2] to control photoluminescence linewidth and enhance photoluminescence intensity.The main challenge for using s-SWNT@PFO in optoelectronics lies in the difficulty to establish good electrical contact with a PFO embedded carbon nanotube. We propose to investigate these issues by tuning the amount of PFO wrapping around s-SWNT. A low pressure annealing process is used to selectively remove PFO around s‑SWNT without burning nanotubes themselves (Figure). The resulting s-SWNT@PFO networks are then probed by AFM, Raman spectroscopy, absorption, photoluminescence and electrical experiments.

Single-walled carbon nanotubes (SWCNTs) are functionalized with copper hexacyanoferrate (CuHCF) nanoparticles to prepare solid substrates for sorption of cesium ions (Cs+) from liquid outflows. The high mechanical resistance and large electrical conductivity of SWCNTs are associated with the ability of CuHCF nanoparticles to selectively complex Cs+ ions in order to achieve membrane-like buckypapers presenting high loading capacity of cesium. The materials are thoroughly characterized using electron microscopy, Raman scattering, X-ray photoelectron spectroscopy and thermogravimetric analyses. Cs sorption isotherms are plotted after having measured the Cs+ concentration by liquid phase ionic chromatography in the solution before and after exposure to the materials. It is found that the total sorption capacity of the material reaches 230 mg g1, and that about one third of the sorbed Cs (80 mg g1) is selectively complexed in the CuHCF nanoparticles grafted on SWCNTs. The quantification of Cs+ ions on different sorption sites is made for the first time, and the high sorption rates open interesting outlooks in the integration of such materials in devices for the controlled sorption and desorption of these ions.

L’encapsulation de molécules pi-conjuguées dans la cavité de nanotubes de carbone monofeuillets permet l’élaboration de nano-systèmes hybrides aux propriétés optoélectroniques modulables. Cette étude concerne le confinement de quaterthiophene dans des nanotubes de différents diamètres. Les interactions physiques entre les chromophores confinées et les nanotubes hôtes sont étudiées par spectroscopies de photoluminescence (PL) et de diffusion Raman. Les mesures de PL montrent une amélioration importante de l'intensité de photoluminescence (facteur 5) pour les nanotubes de faibles diamètres (0.9 nm). Les modes Raman haute fréquence (bande G autour de 1600 cm-1) des systèmes hybrides présentent une baisse d'intensité associée à des modifications de profil et de position. Ces différents comportements sont compatibles avec un transfert d'électrons de la molécule vers le nanotube. De plus, proche de l’énergie d’absorption de la molécule confinée, les effets sur la bande G sont amplifiés, suggérant fortement un transfert d'électrons photo-induit. Enfin, le profil Breit-Wigner-Fano (caractéristique du couplage électron-phonon dans les nanotubes métalliques) de la bande G est fortement affecté pour les nanotubes métalliques fonctionnalisés en surface, ce qui traduit un affaiblissement du couplage électron-phonon. Après encapsulation du quaterthiophene, ce profil particulier est retrouvé, ce qui suggère fortement un renforcement du couplage. Ainsi, le confinement de molécules pi-conjuguées dans les nanotubes de carbone permet de déplacer le niveau de Fermi du nanotube et, par conséquent, de moduler les propriétés opto-électroniques.

Single-walled carbon nanotubes (SWCNTs) are functionalized with copper hexacyanoferrate (CuHCF) nanoparticles and therefore constitutes promising solid substrates for the sorption of Cs+ ions from liquid effluents. The high mechanical resistance and large electrical conductivity of SWCNTs are associated to the ability of CuHCF nanoparticles to selectively complex Cs+ ions in order to achieve membrane-like buckypapers presenting high loading capacity of cesium. The materials are thoroughly characterized using electron microscopy, Raman scattering, X-ray photoelectron spectroscopy and thermogravimetric analyses. Cs sorption isotherms are plotted after liquid phase ionic chromatography of the Cs solutions before and after exposure to the materials. It is found that the total sorption capacity of the material reaches 230 mg.g-1, and that one third of the sorbed Cs (80 mg.g-1) is selectively complexed in the CuHCF nanoparticles grafted on SWCNTs. These high values open interesting perspectives in the integration of such materials in electrically driven devices for the controlled sorption and desorption of these ions.