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Nanostructures & Spectroscopie
(68) Production(s) de l'année 2017
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An ab initio investigation of photoswitches adsorbed onto metal oxide surfaces: the case of donor–acceptor Stenhouse adduct photochromes on TiO 2 anatase
Auteur(s): Belhboub A., Boucher Florent, Jacquemin Denis
(Article) Publié:
Journal Of Materials Chemistry C, vol. 5 p.1624 - 1631 (2017)
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Experimental and first-principles calculation study of the pressure-induced transitions to a metastable phase in GaPO4 and in the solid solution AlPO4-GaPO4
Auteur(s): Angot E., Huang B., Levelut C., Le Parc R., Hermet P., Pereira A. S., Aquilanti G., Frapper G., Cambon Olivier, Haines J.
(Article) Publié:
Physical Review B, vol. 1 p.033607 (2017)
Texte intégral en Openaccess :
Ref HAL: hal-01677334_v1
DOI: 10.1103/PhysRevMaterials.1.033607
WoS: WOS:000416565300001
Exporter : BibTex | endNote
2 Citations
Résumé: alpha-Quartz-type gallium phosphate and representative compositions in the AlPO4-GaPO4 solid solution were studied by x-ray powder diffraction and absorption spectroscopy, Raman scattering, and by first-principles calculations up to pressures of close to 30 GPa. A phase transition to a metastable orthorhombic high-pressure phase along with some of the stable orthorhombic Cmcm CrVO4-type material is found to occur beginning at 9 GPa at 320 degrees C in GaPO4. In the case of the AlPO4-GaPO4 solid solution at room temperature, only the metastable orthorhombic phase was obtained above 10 GPa. The possible crystal structures of the high-pressure forms of GaPO4 were predicted from first-principles calculations and the evolutionary algorithm USPEX. A predicted orthorhombic structure with a Pmn2(1) space group with the gallium in sixfold and phosphorus in fourfold coordination was found to be in the best agreement with the combined experimental data from x-ray diffraction and absorption and Raman spectroscopy. This method is found to very powerful to better understand competition between different phase transition pathways at high pressure.
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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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Adsorption-Induced Structural Phase Transformation in Nanopores
Auteur(s): Kuchta Bogdan, Dundar Ege, Formalik F., Llewellyn Philip L., Firlej L.
(Article) Publié:
Angewandte Chemie / Angew Chem Int Ed, vol. p. (2017)
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CVD Growth of Graphene on SiC (0001): Influence of Substrate Offcut
Auteur(s): Dagher Roy, Jouault B., Paillet M., Bayle M., Nguyen Luan, Portail Marc, Zielinski Marcin, Chassagne Thierry, Cordier Yvon, Michon Adrien
(Article) Publié:
Materials Science Forum, vol. 897 p.731 - 734 (2017)
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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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