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Confinement dans les nanotubes
(34) Production(s) de l'année 2017
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Solvation and Dynamics of Lithium Ions in Carbonate-Based Electrolytes during Cycling Followed by Operando Infrared Spectroscopy: The Example of NiSb 2 , a Typical Negative Conversion-Type Electrode Material for Lithium Batteries
Auteur(s): Marino Cyril, Boulaoued Athmane, Fullenwarth Julien, Maurin D., Louvain Nicolas, Bantignies J.-L., Stievano Lorenzo, Monconduit Laure
(Article) Publié:
The Journal Of Physical Chemistry C, vol. 121 p.26598 - 26606 (2017)
Ref HAL: hal-01661243_v1
DOI: 10.1021/acs.jpcc.7b06685
WoS: 000417671500003
Exporter : BibTex | endNote
14 Citations
Résumé: Conversion-type electrode materials show extremely interesting performance in terms of capacity, which is however usually associated with bad Coulombic efficiency. The latter is mainly the consequence of the relentless evolution of solid electrolyte interphase (SEI) formed and/or dissolved during conversion/back-conversion reactions on the continuously reshaping active material surface. The thorough comprehension of the dynamic processes occurring during cycling in a working electrochemical cell, such as solvation/desolvation of ionic species and formation/dissolution of the SEI at the electrode/electrolyte interface, is thus of utmost relevance in the study of electrochemical mechanism and performance of conversion-type electrode materials. Operando Fourier transform infrared (FTIR) spectroscopy, one of the methods of choice for the study of such phenomena, was applied to study the dynamic interfacial properties of NiSb2, a representative intermetallic conversion-type electrode material for Li batteries, during cycling in the presence of a commercial electrolyte based on LiPF6 dissolved in a mixture of ethylene carbonate (EC) and dimethyl carbonate (DMC). Using a specifically developed in situ ATR-IR electrochemical cell, it was possible to correlate the electrochemical processes to the ratio between solvent molecules associated with Li+ ions and free solvent molecules and thus to follow the dynamic evolution of the concentration of lithium in the electrolyte during cycling.
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Photoluminescence from an individual double-walled carbon nanotube
Auteur(s): Levshov D., Parret R., Tran H.-N., Michel T., Cao Thi Thanh, Nguyen van Chuc, Arenal Raul, Popov Valentin N., Rochal Sergei B., Sauvajol J.-L., Zahab A. A., Paillet M.
(Article) Publié:
Physical Review B, vol. 96 p.195410 (2017)
Texte intégral en Openaccess :
Ref HAL: hal-01653173_v1
DOI: 10.1103/PhysRevB.96.195410
WoS: WOS:000414527500008
Exporter : BibTex | endNote
9 Citations
Résumé: We report direct and unambiguous evidence of the existence of inner semiconducting tube (ISCT) photoluminescence (PL) from measurements performed on four individual freestanding index-identified double-walled carbon nanotubes (DWNTs). Based on thorough Rayleigh scattering, Raman scattering, and PL experiments, we are able to demonstrate that the ISCT PL is observed with a quantum yield estimated to be a few 10−6 independent of the semiconducting or metallic nature of the outer tube. This result is mainly attributed to ultrafast exciton transfer from the inner to outer tube. Furthermore, by carrying out PL excitation experiments on the (14,1)@(15,12) DWNT, we show that the ISCT PL can be detected through the optical excitation of the outer tube, indicating that the exciton transfer can also occur in the opposite way.
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Carbon nanotubes functionalized with copper hexacyanoferrate nanoparticles
for a selective extraction of cesium from nuclear waste
Auteur(s): Alvarez L.
Conférence invité: 2nd International Symposium on Physics of Data Storage (ISPDS-2) (Meknes, MA, 2017-10-31)
Résumé: 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.
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Confinement de molécules pi-conjuguées dans les nanotubes de carbone monofeuillets: étude des transferts de charge
Auteur(s): Alvarez L.
Conference: Deuxième Congrès National Science et Technologie des Systèmes pi-Conjugués: SPIC 2017 (Limoges, FR, 2017-10-17)
Ref HAL: hal-01633073_v1
Exporter : BibTex | endNote
Résumé: 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.
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Voltage-activated transport of ions through single-walled carbon nanotubes
Auteur(s): Yazda K., Tahir S., Michel T., Loubet Bastien, Manghi Manoel, Bentin Jeremy, Picaud Fabien, Palmeri J., Henn F., Jourdain V.
(Article) Publié:
Nanoscale, vol. 9 p.11976-11986 (2017)
Ref HAL: hal-01586169_v1
DOI: 10.1039/c7nr02976d
WoS: WOS:000408435400019
Exporter : BibTex | endNote
13 Citations
Résumé: Ionic transport through single-walled carbon nanotubes (SWCNTs) is promising for many applications but remains both experimentally challenging and highly debated. Here we report ionic current measurements through microfluidic devices containing one or several SWCNTs of diameter of 1.2 to 2 nm unexpectedly showing a linear or a voltage-activated I-V dependence. Transition from an activated to a linear behavior, and stochastic fluctuations between different current levels were notably observed. For linear devices, the high conductance confirmed with different chloride salts indicates that the nanotube/water interface exhibits both a high surface charge density and flow slippage, in agreement with previous reports. In addition, the sublinear dependence of the conductance on the salt concentration points toward a charge-regulation mechanism. Theoretical modelling and computer simulations show that the voltage-activated behavior can be accounted for by the presence of local energy barriers along or at the ends of the nanotube. Raman spectroscopy reveals strain fluctuations along the tubes induced by the polymer matrix but displays insufficient doping or variations of doping to account for the apparent surface charge density and energy barriers revealed by ion transport measurements. Finally, experimental evidence points toward environment-sensitive chemical moieties at the nanotube mouths as being responsible for the energy barriers causing the activated transport of ions through SWCNTs within this diameter range.
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Copper hexacyanoferrate functionalized singlewalled carbon nanotubes for selective cesium extraction
Auteur(s): Draouil H., Alvarez L., Causse J., Flaud V., Zaibi M. A., Bantignies J.-L., Oueslati M., Cambedouzou J.
(Article) Publié:
New Journal Of Chemistry, vol. 41 p.7705-7713 (2017)
Texte intégral en Openaccess :
Ref HAL: hal-01576846_v1
DOI: 10.1039/c7nj00879a
WoS: WOS:000406192800091
Exporter : BibTex | endNote
9 Citations
Résumé: 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.
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High temperature annealing and CVD growth of few-layer graphene on bulk AlN and AlN templates
Auteur(s): Dagher R., Matta S., Parret R., Paillet M., Jouault B., Nguyen L., Portail M., Zielinski M., Chassagne T., Tanaka S., Brault J., Cordier Y., Michon A.
(Article) Publié:
Physica Status Solidi A, vol. 214 p.1600436 (2017)
Ref HAL: hal-01563258_v1
DOI: 10.1002/pssa.201600436
WoS: WOS:000402158300006
Exporter : BibTex | endNote
6 Citations
Résumé: Graphene and AlN are promising materials, interesting to combine together. In this study, we will present first results for direct growth of graphene on bulk AlN and on AlN templates using chemical vapor deposition, including the annealing of these substrates at high temperatures. Atomic force microscopy (AFM) enabled us to study the evolution of the AlN surface morphology after annealing and growth. Few-layer graphene deposition is demonstrated on the basis of X-ray photoemission and Raman spectroscopy
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