4 results on '"Jean-Luc Rouvière"'
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2. Synthesis of relaxed Ge0.9Sn0.1/Ge by nanosecond pulsed laser melting
- Author
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Enrico Di Russo, Francesco Sgarbossa, Pierpaolo Ranieri, Gianluigi Maggioni, Samba Ndiaye, Sébastien Duguay, François Vurpillot, Lorenzo Rigutti, Jean-Luc Rouvière, Vittorio Morandi, Davide De Salvador, Enrico Napolitani, Dipartimento di Fisica e Astronomia [Bologna], Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO), Groupe de physique des matériaux (GPM), Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Matériaux Avancés (IRMA), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Magnetic Resonance (RM ), Modélisation et Exploration des Matériaux (MEM), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), and Consiglio Nazionale delle Ricerche [Bologna] (CNR)
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General Physics and Astronomy ,Surfaces and Interfaces ,General Chemistry ,Condensed Matter Physics ,[SPI.MAT]Engineering Sciences [physics]/Materials ,Surfaces, Coatings and Films ,germanium ,GeSn ,strain ,pulsed laser melting ,tin ,germanium, tin, GeSn, pulsed laser melting, strain, defects ,[SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics ,defects - Abstract
International audience
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- 2023
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3. Influence of milling on structural and microstructural properties of cerium oxide: Consequence of the surface activation on the dissolution kinetics in nitric acid
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Hanako Okuno, Thibaud Delahaye, Pascal Roussel, Gilles Leturcq, Julia Hidalgo, and Jean-Luc Rouvière
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Cerium oxide ,Metals and Alloys ,Oxide ,chemistry.chemical_element ,02 engineering and technology ,Activation energy ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Industrial and Manufacturing Engineering ,0104 chemical sciences ,chemistry.chemical_compound ,Cerium ,chemistry ,Chemical engineering ,Leaching (chemistry) ,Specific surface area ,Materials Chemistry ,Crystallite ,0210 nano-technology ,Dissolution - Abstract
Ceria (CeO2) is known as a refractory oxide for dissolution in nitric acid, since the leaching reaction is thermodynamically unfavorable, except when it is complexed by nitrates but with very slow kinetics. To enhance dissolution, surface activation was achieved using high-energy milling. With the mechanically-activated cerium oxide, leaching in nitric acid reached 36%. The mechanical activation of the solid caused structural and microstructural changes (particle size, specific surface area, crystallite size, lattice strain, defects…). After one hour, the cleavage induced by energetic milling generated two populations: nanoparticles and grains containing defects like dislocations. Beside crystallite size and micro-strain evaluation using X-ray diffraction, cerium oxidation state was measured by Electron Energy-Loss Spectroscopy (EELS) analyses while linear defects were pictured by Transmission Electron Microscopy (TEM) observations. On one hand, it was found that the nanoparticles formed during milling process greatly enhance the dissolution reaction by the creation of Ce3+ thin layers of a few nanometer depth on their surfaces. On the other hand, it is shown that dislocations represent another way to increase the kinetics by activation energy. In conclusion, dissolution rate's growth can be due to different parameters like the leaching of the smallest particles, the presence of reduced oxidation state on nanoparticles and some highly reactive sites concentrating structural defects such as dislocation nodes. Finally, as ceria is also well known to be a safe analogue of PuO2, especially for dissolution studies, a solution for improving the dissolution of ceria would probably also be useful for dissolving the oxides rich in Pu.
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- 2022
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4. Practice of electron microscopy on nanoparticles sensitive to radiation damage: CsPbBr3 nanocrystals as a case study
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Tuan M. Duong, Kshipra Sharma, Fabio Agnese, Jean-Luc Rouviere, Hanako Okuno, Stéphanie Pouget, Peter Reiss, and Wai Li Ling
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lead halide perovskite ,low-dose electron microscopy ,electron diffraction ,cryo- TEM ,STEM ,graphene support film ,Chemistry ,QD1-999 - Abstract
In-depth and reliable characterization of advanced nanoparticles is crucial for revealing the origin of their unique features and for designing novel functional materials with tailored properties. Due to their small size, characterization beyond nanometric resolution, notably, by transmission electron microscopy (TEM) and associated techniques, is essential to provide meaningful information. Nevertheless, nanoparticles, especially those containing volatile elements or organic components, are sensitive to radiation damage. Here, using CsPbBr3 perovskite nanocrystals as an example, strategies to preserve the native structure of radiation-sensitive nanocrystals in high-resolution electron microscopy studies are presented. Atomic-resolution images obtained using graphene support films allow for a clear comparison with simulation results, showing that most CsPbBr3 nanocrystals are orthorhombic. Low-dose TEM reveals faceted nanocrystals with no in situ formed Pb crystallites, a feature observed in previous TEM studies that has been attributed to radiation damage. Cryo-electron microscopy further delays observable effects of radiation damage. Powder electron diffraction with a hybrid pixel direct electron detector confirms the domination of orthorhombic crystals. These results emphasize the importance of optimizing TEM grid preparation and of exploiting data collection strategies that impart minimum electron dose for revealing the true structure of radiation-sensitive nanocrystals.
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- 2022
- Full Text
- View/download PDF
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