Search

Your search keyword '"NAYRAL"' showing total 324 results
Start Over Author "NAYRAL"

Refine your results

324 results on '"NAYRAL"'

2. Low-temperature optical constants of amorphous silicate dust analogues

Author

Demyk, K., Gromov, V., Meny, C., Ysard, N., Paradis, D., Jones, A. P., Petitprez, D., Hubert, P., Leroux, H., Nayral, C., and Delpech, F.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

Cosmic dust models are key ingredients in advancing our understanding of astronomical environments as diverse as interstellar clouds in galaxies, circumstellar envelopes around evolved and young stars, and protoplanetary disks. Such models consist of several dust populations, each with different compositions and size distributions. They may also consider different grain shapes, although most models assume spherical grains. All include a component of silicate dust. The absorption and emission properties of these dust components are calculated from the optical constants of each dust material which have various experimental, phenomenological, and theoretical origins depending on the model. We aim to provide the community with new sets of optical constants for amorphous silicate dust analogues at low temperatures. The analogues consist of four Mg-rich silicate samples of stoichiometry ranging from enstatite to olivine, and of eight samples of Mg and Fe rich silicates with a pyroxene stoichiometry and differing magnesium and iron content. We calculated the optical constants from transmission measurements using the Kramers-Kronig relations, assuming that the grains are small compared to the wavelength and prolate in shape with axis ratios of 1.5 and 2 for the Mg and Fe rich samples, respectively. New optical constants for silicate dust analogues were calculated over the wavelength range from 5 to 800-1000 microns, depending on the sample, and at temperatures of 10, 30, 100, 200, and 300 K.We determined the uncertainties on the derived optical constants based on the assumptions used to calculate them. To facilitate the use of these data in cosmic dust models, we provide optical constants extrapolated outside the measured spectral range into the UV-NIR and mm-cm wavelength ranges, as well as formulae that can be used to interpolate them at any temperature in the range 10 - 300 K.

Published
2022
Full Text
View/download PDF

8. Low-temperature MIR to submillimeter mass absorption coefficient of interstellar dust analogues II: Mg and Fe-rich amorphous silicates

Author

Demyk, K., Meny, C., Leroux, H., Depecker, C, Brubach, J. -B., Roy, P., Nayral, C., and Ojo, W. -S.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

To model the cold dust emission observed in the diffuse interstellar medium, in dense molecular clouds or in cold clumps that could eventually form new stars, it is mandatory to know the physical and spectroscopic properties of this dust and to understand its emission. This work is a continuation of previous studies aiming at providing astronomers with spectroscopic data of realistic cosmic dust analogues for the interpretation of observations. Ferromagnesium amorphous silicate dust analogues were produced with a mean composition close to $\mathrm{Mg_{1-x}Fe_{x}SiO_3}$ with x = 0.1, 0.2, 0.3, 0.4. Part of each sample was annealed at 500$^{\circ}$C for two hours in a reducing atmosphere to modify the oxidation state of iron. We have measured the mass absorption coefficient (MAC) of these ferromagnesium amorphous silicate dust analogues in the spectral domain 30 - 1000 $\mu$m for grain temperature in the range 10 - 300 K and at room temperature in the 5 - 40 $\mu$m range. The MAC of ferromagnesium samples behaves in the same way as the MAC of pure Mg-rich amorphous silicate samples. In the 30 - 300 K range, the MAC increases with increasing grain temperature whereas in the range 10 - 30 K, we do not see any change of the MAC. The MAC cannot be described by a single power law in ${\lambda}^{-\beta}$. The MAC of all the samples is much higher than the MAC calculated by dust models. The complex behavior of the MAC of amorphous silicates with wavelength and temperature is observed whatever the exact silicate composition (Mg vs. Fe amount). It is a universal characteristic of amorphous materials, and therefore of amorphous cosmic silicates, that should be taken into account in astronomical modeling. The enhanced MAC of the measured samples compared to the MAC calculated for cosmic dust model implies that dust masses are overestimated by the models.

Published
2017
Full Text
View/download PDF

9. Low temperature MIR to submillimeter mass absorption coefficient of interstellar dust analogues I: Mg-rich glassy silicates

Author

Demyk, K., Meny, C., Lu, X. -H., Papatheodorou, G., Toplis, M. J., Leroux, H., Depecker, C., Brubach, J. -B., Roy, P., Nayral, C., Ojo, W. -S., Delpech, F., Paradis, D., and Gromov, V.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

A wealth of data from the Herschel and Planck satellites and now from ALMA, revealing cold dust thermal emission, is available for astronomical environments ranging from interstellar clouds, cold clumps, circumstellar envelops, and protoplanetary disks. The interpretation of these observations relies on the understanding and modeling of cold dust emission and on the knowledge of the dust optical properties. The aim of this work is to provide astronomers with a set of spectroscopic data of realistic interstellar dust analogues that can be used to interpret the observations. Glassy silicates of mean composition (1-x)MgO - xSiO2 with x = 0.35, 0.40 and 0.50 were synthesized. The mass absorption coefficient (MAC) of the samples was measured in the spectral domain 30 - 1000 $\mu$m for grain temperature in the range 300 K - 10 K and at room temperature in the 5 - 40 $\mu$m domain. We find that the MAC of all samples varies with the grains temperature. In the FIR/submm, and above 30K, the MAC value at a given wavelength increases with the temperature as thermally activated absorption processes appear. The studied materials exhibit different and complex behaviors at long wavelengths (lambda $\geq$ 200 to 700 $\mu$m depending on the samples) and the MAC cannot be approximated by a single power law in ${\lambda}^{-\beta}$. These behaviors are attributed to the amorphous nature of dust and to the amount and nature of the defects within this amorphous structure. Above 20 $\mu$m, the measured MAC are much higher than the MAC calculated from interstellar silicate dust models indicating that the analogues measured in this study are more emissive than the silicates in cosmic dust models. This has important astrophysical implications because masses are overestimated by the models. Moreover, constraints on elemental abundance of heavy elements in cosmic dust models are relaxed

Published
2017
Full Text
View/download PDF

14. Cd3P2/Zn3P2 Core-Shell Nanocrystals: Synthesis and Optical Properties

Author

Benjamin F. P. McVey, Robert A. Swain, Delphine Lagarde, Wilfried-Solo Ojo, Kaltoum Bakkouche, Cécile Marcelot, Bénédicte Warot, Yann Tison, Hervé Martinez, Bruno Chaudret, Céline Nayral, and Fabien Delpech

Subjects
nanomaterials, quantum dots, nanocrystal, core-shell nanostructure, cadmium phosphide, zinc phosphide, Chemistry, QD1-999
Abstract

II–V semiconductor nanocrystals such as Cd3P2 and Zn3P2 have enormous potential as materials in next-generation optoelectronic devices requiring active optical properties across the visible and infrared range. To date, this potential has been unfulfilled due to their inherent instability with respect to air and moisture. Core-shell system Cd3P2/Zn3P2 is synthesized and studied from structural (morphology, crystallinity, shell diameter), chemical (composition of core, shell, and ligand sphere), and optical perspectives (absorbance, emission-steady state and time resolved, quantum yield, and air stability). The improvements achieved by coating with Zn3P2 are likely due to its identical crystal structure to Cd3P2 (tetragonal), highlighting the key role crystallographic concerns play in creating cutting edge core-shell NCs.

Published
2022
Full Text
View/download PDF

17. Influence of a transverse static magnetic field on the magnetic hyperthermia properties and high-frequency hysteresis loops of ferromagnetic FeCo nanoparticles

Author

Mehdaoui, B., Carrey, J., Stadler, M., Cornejo, A., Nayral, C., Delpech, F., Chaudret, B., and Respaud, M.

Subjects
Condensed Matter - Materials Science
Abstract

The influence of a transverse static magnetic field on the magnetic hyperthermia properties is studied on a system of large-losses ferromagnetic FeCo nanoparticles. The simultaneous measurement of the high-frequency hysteresis loops and of the temperature rise provides an interesting insight into the losses and heating mechanisms. A static magnetic field of only 40 mT is enough to cancel the heating properties of the nanoparticles, a result reproduced using numerical simulations of hysteresis loops. These results cast doubt on the possibility to perform someday magnetic hyperthermia inside a magnetic resonance imaging setup., Comment: 6 pages, 3 figures

Published
2012
Full Text
View/download PDF

18. Low temperature FIR and submm mass absorption coefficient of interstellar silicate dust analogues

Author

Coupeaud, A., Demyk, K., Meny, C., Nayral, C., Delpech, F., Leroux, H., Depecker, C., Creff, G., Brubach, J. B., and Roy, P.

Subjects
Astrophysics - Astrophysics of Galaxies, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

Cold dust grains emission in the FIR/submm is usually expressed as a modified black body law in which the dust mass absorption coefficient (MAC), is described with a temperature- and wavelength-independent emissivity spectral index, beta. However, numerous data from space and balloon-born missions and recently from Herschel and Planck show that dust emission is not well understood, as revealed by the observed anti-correlation of beta with the grain temperature. In order to give astronomers the necessary data to interpret FIR/submm observations, we synthesised analogues of interstellar amorphous and crystalline silicate grains, rich in Mg and Ca, and having stiochiometry of olivine and pyroxene and measured their MAC, in the 100-1000/1500 \mum range for grain temperatures varying from 300 to 10 K. We find that the grain MAC decreases when the grain temperature decreases and that the local spectral index, beta, defined as the slope of the MAC curve, is anti-correlated with the grain temperature. These variations, which are not observed in the crystallised samples, are related to the amorphous nature of the samples. In addition, the spectral shape of the MAC is complex: at short wavelengths (lambda < 500/700 \mum), beta is in the range 1.6 - 2.1 for all grain temperature and grain composition whereas at longer wavelengths (lambda > 500/700 \mum), beta < 2 for samples with a pyroxene stoichiometry and beta > 2 for samples with an olivine stoichiometry. Hence, the simplifying asymptotic expression based on a single temperature- and wavelength-independent spectral index used by astronomers is not appropriate to describe the dust MAC and thus the dust emission, and may induce significant errors on the derived parameters such as the dust mass and the dust physical and chemical properties. Instead, dust emission models should use the dust MAC as a function of wavelength and temperature.

Published
2011
Full Text
View/download PDF

19. Far-infrared to millimeter astrophysical dust emission I: A model based on physical properties of amorphous solids

Author

Meny, C., Gromov, V., Boudet, N., Bernard, J. -Ph., Paradis, D., and Nayral, C.

Subjects
Astrophysics
Abstract

We propose a new description of astronomical dust emission in the spectral region from the Far-Infrared to millimeter wavelengths. Unlike previous classical models, this description explicitly incorporates the effect of the disordered internal structure of amorphous dust grains. The model is based on results from solid state physics, used to interpret laboratory data. The model takes into account the effect of absorption by Disordered Charge Distribution, as well as the effect of absorption by localized Two Level Systems. We review constraints on the various free parameters of the model from theory and laboratory experimental data. We show that, for realistic values of the free parameters, the shape of the emission spectrum will exhibit very broad structures which shape will change with the temperature of dust grains in a non trivial way. The spectral shape also depends upon the parameters describing the internal structure of the grains. This opens new perspectives as to identifying the nature of astronomical dust from the observed shape of the FIR/mm emission spectrum. A companion paper will provide an explicit comparison of the model with astronomical data., Comment: accepted in A&A, 21 pages, 9 figures

Published
2007
Full Text
View/download PDF

21. Conserver la biodiversité avec les ONG en Nouvelle-Calédonie: décolonisation ou délégation de gestion ?

Author

Mélissa Nayral and Marie Toussaint

Subjects
governance, protected areas, biodiversity, NGO, conservation, New Caledonia, Environmental sciences, GE1-350
Abstract

This text questions the important role played by two major environmental NGOs, CI and WWF, in the process of defining and governing two protected areas located in the northern province of New Caledonia. With its unique legal status, this atypical Pacific territory of French overseas territories, now recognized as a hotspot for biodiversity (Myers et al., 2000), is indeed in the middle of a unique process of negotiated decolonization. This includes skills transfers from France to this "non-decolonized former colony" (Demmer and Salomon, 2013) that have already allowed the emergence of the preservation of biodiversity as a major political issue. With the concomitant inclusion of environmental concerns in international agendas, and very much like in other territories (Aubertin 2005, Léna 2002), several non-governmental conservation organizations (NGOs) have gradually contributed to the definition of environmental issues and local environmental public policies. Based on two case studies, this text shows the mechanisms by which these NGOs initially took part in the process of reviewing the former parks and natural reserves of the territory before becoming privileged partners of the local institutions.

Published
2020
Full Text
View/download PDF

27. Low-temperature optical constants of amorphous silicate dust analogues

Author

Demyk, Karine, Gromov, Vladimir, Meny, Claude, Ysard, N., Paradis, Deborah, Jones, Anthony P., Petitprez, Denis, Hubert, Patrick, Leroux, Hugues, Nayral, Céline, Delpech, Fabien, Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Physicochimie des Processus de Combustion et de l’Atmosphère - UMR 8522 (PC2A), Université de Lille-Centre National de la Recherche Scientifique (CNRS), Laboratoire d’Optique Atmosphérique - UMR 8518 (LOA), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Unité Matériaux et Transformations - UMR 8207 (UMET), Centrale Lille-Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), and ANR-11-BS56-0029,CIMMES,La poussière interstellaire froide : études expérimentales et modélisation(2011)

Subjects
solid state -Techniques, FOS: Physical sciences, Astronomy and Astrophysics, )dust, Astrophysics - Astrophysics of Galaxies, Astrochemistry -Methods, ISM -Infrared, Space and Planetary Science, extinction-submillimetre, Astrophysics of Galaxies (astro-ph.GA), [SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], laboratory, spectroscopic -(ISM, ISM
Abstract

Context. Cosmic dust models are key ingredients in advancing our understanding of astronomical environments as diverse as interstellar clouds in galaxies, circumstellar envelopes around evolved and young stars, and protoplanetary disks. Such models consist of several dust populations, each with different compositions and size distributions. They may also consider different grain shapes, although most models assume spherical grains. All include a component of silicate dust. The absorption and emission properties of these dust components are calculated from the optical constants of each dust material which have various experimental, phenomenological, and theoretical origins depending on the model. Aims. We aim to provide the community with new sets of optical constants for amorphous silicate dust analogues at low temperatures. The analogues consist of four Mg-rich silicate samples of stoichiometry ranging from enstatite to olivine, and of eight samples of Mg- and Fe-rich silicates with a pyroxene stoichiometry and differing magnesium and iron content. Methods. We calculated the optical constants from transmission measurements using the Kramers-Kronig relations, assuming that the grains are small compared to the wavelength and prolate in shape with axis ratios of 1.5 and 2 for the Mg- and Fe-rich samples, respectively. Results. New optical constants for silicate dust analogues of various compositions were calculated over the wavelength range from 5 to 800 µm or 1000 µm, depending on the sample, and at temperatures of 10, 30, 100, 200, and 300 K. We determined the uncertainties on the derived optical constants based on the assumptions used to calculate them. To facilitate the use of these data in cosmic dust models, we provide optical constants extrapolated outside the measured spectral range into the ultraviolet(UV)/visual(VIS)/near-infrared(NIR) and millimetre and centimetre wavelength ranges, as well as formulae that can be used to interpolate the optical constants at any temperature in the range 10–300 K.

Published
2022
Full Text
View/download PDF

29. Cd3P2/Zn3P2 Core-Shell Nanocrystals: Synthesis and Optical Properties

Author

McVey, Benjamin F. P., primary, Swain, Robert A., additional, Lagarde, Delphine, additional, Ojo, Wilfried-Solo, additional, Bakkouche, Kaltoum, additional, Marcelot, Cécile, additional, Warot, Bénédicte, additional, Tison, Yann, additional, Martinez, Hervé, additional, Chaudret, Bruno, additional, Nayral, Céline, additional, and Delpech, Fabien, additional

Published
2022
Full Text
View/download PDF

30. Cd

Author

Benjamin F P, McVey, Robert A, Swain, Delphine, Lagarde, Wilfried-Solo, Ojo, Kaltoum, Bakkouche, Cécile, Marcelot, Bénédicte, Warot, Yann, Tison, Hervé, Martinez, Bruno, Chaudret, Céline, Nayral, and Fabien, Delpech

Abstract

II-V semiconductor nanocrystals such as Cd

Published
2022

31. Full-Spectrum InP-Based Quantum Dots with Near-Unity Photoluminescence Quantum Efficiency

Author

Hannes Van Avermaet, Pieter Schiettecatte, Sandra Hinz, Luca Giordano, Fabio Ferrari, Céline Nayral, Fabien Delpech, Janina Maultzsch, Holger Lange, Zeger Hens, Universiteit Gent = Ghent University (UGENT), Universität Hamburg (UHH), Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
optical materials, color conversion, nanocrystals, restriction of hazardous substances, General Engineering, monochromatic, General Physics and Astronomy, [CHIM]Chemical Sciences, General Materials Science, core/shell
Abstract

Photoluminescent color conversion by quantum dots (QDs) makes possible the formation of spectrum-on-demand light sources by combining blue LEDs with the light generated by a specific blend of QDs. Such applications, however, require a near-unity photoluminescence quantum efficiency since self-absorption magnifies disproportionally the impact of photon losses on the overall conversion efficiency. Here, we present a synthesis protocol for forming InP-based QDs with +90% quantum efficiency across the full visible spectrum from blue/cyan to red. The central features of our approach are as follows: (1) the formation of InP core QDs through one-batch-one-size reactions based on aminophosphine as the phosphorus precursor, (2) the introduction of a core/shell/shell InP/Zn(Se,S)/ZnS structure, and (3) the use of specific interfacial treatments, most notably the saturation of the ZnSe surface with zinc acetate prior to ZnS shell growth. Moreover, we adapted the composition of the Zn(Se,S) inner shell to attain the intended emission color while minimizing line broadening induced by the InP/ZnS lattice mismatch. The protocol is established by analysis of the QD composition and structure using multiple techniques, including solid-state nuclear magnetic resonance spectroscopy and Raman spectroscopy, and verified for reproducibility by having different researchers execute the same protocol. The realization of full-spectrum, +90% quantum efficiency will strongly facilitate research into light-matter interaction in general and luminescent color conversion in particular through InP-based QDs.

Published
2022
Full Text
View/download PDF

32. Micropatterning of Adhesive Epoxy with Embedded Colloidal Quantum Dots for Authentication and Tracing

Author

Simon Raffy, Fabien Delpech, Louis Vaure, Céline Nayral, Romain Platel, François Guerin, Laurence Ressier, and Etienne Palleau

Subjects
Authentication, Materials science, Photoluminescence, Nanotechnology, Epoxy, Tracing, Tracking (particle physics), Quantum dot, visual_art, visual_art.visual_art_medium, ComputingMilieux_COMPUTERSANDSOCIETY, General Materials Science, Adhesive, Micropatterning
Abstract

Permanently renewing security and tracking technologies is mandatory to fight the worldwide growing problem of conterfeiting, doped by the development of e-commerce and the consequences of social/s...

Published
2021
Full Text
View/download PDF

35. « Du rémouleur au freelancer » Enquête ethnographique sur les nouveaux métiers dans le territoire du Parc des Causses du Quercy

Author

Nayral, Mélissa, Laboratoire Interdisciplinaire Solidarités, Sociétés, Territoires (LISST), École des hautes études en sciences sociales (EHESS)-Université Toulouse - Jean Jaurès (UT2J)-Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure de Formation de l'Enseignement Agricole de Toulouse-Auzeville (ENSFEA), and Parc Naturel Régional des Causses du Quercy

Subjects
[SHS.ANTHRO-SE]Humanities and Social Sciences/Social Anthropology and ethnology
Published
2021

36. Unraveling the role of zinc complexes on indium phosphide nanocrystal chemistry.

Author

McVey, B. F. P., Swain, R. A., Lagarde, D., Tison, Y., Martinez, H., Chaudret, B., Nayral, C., and Delpech, F.

Subjects
INDIUM phosphide, ZINC, SURFACE passivation, CHEMISTRY, OPTICAL properties
Abstract

The addition of zinc complexes to the syntheses of indium phosphide nanocrystals (InP NCs) has become commonplace, due to their ability to alter and significantly improve observed optical properties. In this paper, the role of zinc complexes on the synthesis and observed properties of InP is carefully examined. Produced InP and InP:Zn2+ NCs are thoroughly characterized from both structural (core and surface) and optical perspectives over a wide range of Zn2+ compositions (0%–43% atomic content). We find no differences in the physical (NC size and polydispersity) and structural properties (crystallographic phase) of InP and InP:Zn2+ NCs. Optically, significant changes are observed when zinc is added to InP syntheses, including blueshifted absorption edges and maxima, increased quantum yields, and the near elimination of surface state emission. These improved optical properties result from surface passivation by zinc carboxylate moieties. Changes to the optical properties begin at zinc concentrations as low as 5%, demonstrating the high sensitivity of InP optical properties to exogenous species. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
View/download PDF

38. Interdire pour protéger quoi/qui et pour quoi/qui ?La co-gestion des « réserves coutumières » de pêche à Ouvéa (Nlle-Calédonie)

Author

Nayral, Mélissa, Laboratoire Interdisciplinaire Solidarités, Sociétés, Territoires (LISST), École des hautes études en sciences sociales (EHESS)-Université Toulouse - Jean Jaurès (UT2J)-École Nationale Supérieure de Formation de l'Enseignement Agricole de Toulouse-Auzeville (ENSFEA)-Centre National de la Recherche Scientifique (CNRS), École des hautes études en sciences sociales (EHESS)-Université Toulouse - Jean Jaurès (UT2J)-Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure de Formation de l'Enseignement Agricole de Toulouse-Auzeville (ENSFEA), and Nayral, Mélissa

Subjects
[SHS.ANTHRO-SE] Humanities and Social Sciences/Social Anthropology and ethnology, [SHS.ANTHRO-SE]Humanities and Social Sciences/Social Anthropology and ethnology, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2019

39. Effect of nanoparticles on spontaneous Ouzo emulsification

Author

Déborah Iglicki, Fabienne Gauffre, Myrtil L. Kahn, Robert A Swain, Ludivine Rault, Céline Nayral, Clément Goubault, Soizic Chevance, Benjamin F. P. McVey, Bertrand Lefeuvre, Fabien Delpech, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Synthèse Caractérisation Analyse de la Matière (ScanMAT), Université de Rennes (UR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de chimie de coordination (LCC), Institut de Chimie de Toulouse (ICT), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), We wish to thank the region Bretagne (ARED- 107/ NAPOLI), the LCC and the ANR (grant: 2020-CES06-OuzoFan) for Financial support. FD thanks ERC Advanced Grant (MONACAT 2015-694159) and EUR grant NanoX no. ANR-17-EURE-0009., ANR-20-CE06-0031,OuzoFAN,Assemblages de nanoparticules en coques submicroniques par effet Ouzo : vers des résonnateurs optiques(2020), ANR-17-EURE-0009,NanoX,Science et Ingénierie à l'Echelle Nano(2017), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC), Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut de Chimie du CNRS (INC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), and Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Nanoparticle tracking analysis, Nanoparticle, 02 engineering and technology, Material science, Pickering emulsions, 010402 general chemistry, 01 natural sciences, Biomaterials, chemistry.chemical_compound, Colloid and Surface Chemistry, Dynamic light scattering, Limited coalescence, [CHIM]Chemical Sciences, Microemulsion, Tetrahydrofuran, Coalescence (physics), 021001 nanoscience & nanotechnology, Pickering emulsion, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Condensed Matter::Soft Condensed Matter, chemistry, Chemical engineering, Ouzo emulsions, Emulsion, 0210 nano-technology
Abstract

International audience; Particles stabilize fluid interfaces. In particular, oil/water Pickering emulsions undergo limited coalescence, yielding droplets of smaller size as the amount of particles is increased. Herein, we studied the effect of hydrophobic nanoparticles (

Published
2021
Full Text
View/download PDF

40. Création d’outils d’aide au repérage et à l’orientation d’enfants atteints de Troubles liés au Spectre de l’Alcoolisation Fœtale

Author

Huberdeau, Victoire, Nayral, Ariane, Université de Bordeaux (UB), and Philippe Castera

Subjects
Soins de premiers recours, Dépistage, Neurodevelopmental syndrome due to prenatal alcohol exposure, Orientation, Diagnosis, Exposition prénatale à l’alcool, Troubles du Spectre lié à l’alcoolisation Foetale, Primary care, [SDV.MHEP]Life Sciences [q-bio]/Human health and pathology, Fetal alcohol spectrum disorders
Abstract

FASD, the leading cause of non-genetic mental retardation, results from prenatal exposure to alcohol. There is insufficient identification of children with FASD due to professionnals’ lack of knowledge on the subject by professionals. However, with early and personalized care by a specialized multidisciplinary team, these children have the potential to adapt and improve their disabilities. Our goal was to create a tool to help identify and guide children with FASD in order to facilitate this screening for all professionals working with children. We carried out a qualitative study: first, we created version 0 based on current scientific data, which we submitted to an expert group. Then, we adapted to their reviews in order to attest to the scientific validity, creating version 1. Second, we presented version 1 to discussion groups representative of our target population. We synthesized their critiques, creating the final version, attesting to its practical applicability. We obtained two flyers (for children under 3 and over 3 years old) containing relevant information relating to FASD, applicable to first aid, and offering simplified access due to their format. Thus, we have created two flyers in order to optimize identification and potential referral of children with FASD according to the territorial resources.; Contexte : les Troubles du Spectre liés à l’Alcoolisation Foetale (TSAF), première cause de retard mental d’origine non génétique, résultent de l’exposition prénatale à l’alcool. On observe une insuffisance de repérage de ces enfants atteints de TSAF en raison d’une méconnaissance du sujet par les professionnels. Or, pris en charge de façon précoce et personnalisée, par une équipe pluridisciplinaire spécialisée, ces enfants possèdent un potentiel d’adaptation et une amélioration de leurs handicaps. Objectif : créer un outil d’aide au repérage et à l’orientation des enfants atteints de TSAF afin de faciliter ce dépistage à tous les professionnels travaillant avec les enfants. Méthode : étude qualitative : création d’une version 0, basée sur les données actuelles de la science, exposée à un groupe expert, puis secondairement adaptée à leurs critiques afin d’attester de la validité scientifique, créant ainsi la version 1. Présentation de la version 1 à des groupes de discussions représentant notre population cible. Adaptation de la version 1 selon la synthèse de leurs critiques, créant ainsi la version finale, attestant de son applicabilité pratique. Résultat : obtention de deux flyers (un pour les moins de 3 ans, un pour les plus de 3 ans) contenant les informations pertinentes relatives au TSAF, applicables en soins premiers, et offrant un accès simplifié de par son format, permettant le repérage et l’orientation des enfants TSAF. Conclusion : création de deux flyers permettant d‘optimiser le repérage et les orientations des enfants TSAF selon les ressources territoriales.

Published
2021

41. Update of French society for rheumatology recommendations for managing rheumatoid arthritis

Author

Cécile Gaujoux-Viala, Madeleine Dubremetz, Maxime Dougados, Bruno Fautrel, C. Hua, Nathalie Nayral, Alain Saraux, Christophe Richez, Bernard Combe, Alain Cantagrel, Daniel Wendling, Xavier Mariette, Claire Daien, Gérard Thibaud, Laure Gossec, Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier), Institut de Génétique Moléculaire de Montpellier (IGMM), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM), Service de Rhumatologie [CHRU Nîmes], Centre Hospitalier Universitaire de Nîmes (CHU Nîmes), Aide à la Décision pour une Médecine Personnalisé - Laboratoire de Biostatistique, Epidémiologie et Recherche Clinique - EA 2415 (AIDMP), Université Montpellier 1 (UM1)-Université de Montpellier (UM), Department of Rheumatology, Purpan Toulouse, Association Française des Polyarthritiques (AFPric), Service de rhumatologie [CHU Cochin], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Hôpital Cochin [AP-HP], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP), Service de rhumatologie [CHU Pitié Salpêtrière] (GRC-08 EEMOIS), Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU), Service de rhumatologie, Université Paris-Sud - Paris 11 (UP11)-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Hôpital Bicêtre, Département de Rhumatologie[Montpellier], Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier)-Hôpital Lapeyronie, CHU Bordeaux [Bordeaux], Lymphocyte B et Auto-immunité (LBAI), Université de Brest (UBO)-Institut Brestois Santé Agro Matière (IBSAM), Université de Brest (UBO)-Institut National de la Santé et de la Recherche Médicale (INSERM), CHRU Brest - Service de Rhumatologie (CHU - BREST - Rhumato), Centre Hospitalier Régional Universitaire de Brest (CHRU Brest), ANDAR patient organisation, Paris, Service de Rhumatologie, Centre Hospitalier Régional Universitaire de Besançon (CHRU Besançon), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Centre Hospitalier Universitaire de Toulouse (CHU Toulouse), Centre de Physiopathologie Toulouse Purpan (CPTP), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Service de Rhumatologie [CHU Pitié Salpêtrière], CHU Pitié-Salpêtrière [AP-HP], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU)-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU), Lymphocytes B, Autoimmunité et Immunothérapies (LBAI), Université de Brest (UBO)-Institut National de la Santé et de la Recherche Médicale (INSERM)-LabEX IGO Immunothérapie Grand Ouest, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Institut Brestois Santé Agro Matière (IBSAM), Université de Brest (UBO), Association Nationale de Défense contre l'Arthrite Rhumatoide (ANDAR), CCSD, Accord Elsevier, Hôpital Bicêtre-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Université Paris-Sud - Paris 11 (UP11), and Université de Brest (UBO)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut Brestois Santé Agro Matière (IBSAM)

Subjects
Male, medicine.medical_specialty, [SDV.IMM] Life Sciences [q-bio]/Immunology, [SDV]Life Sciences [q-bio], medicine.medical_treatment, Recommendations, Targeted therapy, Arthritis, Rheumatoid, 03 medical and health sciences, 0302 clinical medicine, Rheumatology, Targeted treatment, Internal medicine, Diagnosis, medicine, Humans, 030212 general & internal medicine, Practice Patterns, Physicians', Rheumatoid arthritis, Intensive care medicine, Societies, Medical, 030203 arthritis & rheumatology, business.industry, Task force, Disease Management, Diagnostic strategy, medicine.disease, 3. Good health, Patient management, [SDV] Life Sciences [q-bio], Treatment, DMARD, Systematic review, Antirheumatic Agents, Practice Guidelines as Topic, [SDV.IMM]Life Sciences [q-bio]/Immunology, Female, Methotrexate, France, Rheumatologists, business, Forecasting, medicine.drug
Abstract

International audience; The 2014 French Society for Rheumatology (Société Française de Rheumatologie, SFR) recommendations about the management of rheumatoid arthritis (RA) have been updated by a task force composed of 12 expert rheumatologists, 2 patient self-help group representatives, and an occupational therapist. The material used by the task force included recent EULAR recommendations, a systematic literature review, and expert opinion. Four general principles and 15 recommendations were developed. The general principles emphasize the need for shared decision-making between the rheumatologist and the patient and for a global management program including both pharmacological and non-pharmacological treatments. The recommendations deal with the diagnostic strategy for RA, treatment targets, management organization, drug selection based on the treatment line and prognostic factors, management of remissions, and global patient management. Disease-modifying anti-rheumatic drug (DMARD) therapy should be started as early as possible. Validated composite scores should be determined at regular intervals to assess disease activity - according to the tight disease control concept - to achieve the treatment target, i.e., a remission. Methotrexate is the recommended first-line DMARD. The treatment should be optimized when methotrexate is poorly tolerated or inadequately effective. While waiting for conventional synthetic DMARDs to take effect, glucocorticoid therapy can be used, for a brief period to keep the cumulative dose low. When a sustained remission without structural progression is achieved in a patient who is not taking glucocorticoid therapy, targeted therapy de-escalation according to tight disease control principles should be considered. Patients should be periodically screened for comorbidities and their risk factors, which should be evaluated and treated.

Published
2019
Full Text
View/download PDF

42. Cd 3 P 2 /Zn 3 P 2 Core-Shell Nanocrystals: Synthesis and Optical Properties.

Author

McVey, Benjamin F. P., Swain, Robert A., Lagarde, Delphine, Ojo, Wilfried-Solo, Bakkouche, Kaltoum, Marcelot, Cécile, Warot, Bénédicte, Tison, Yann, Martinez, Hervé, Chaudret, Bruno, Nayral, Céline, and Delpech, Fabien

Subjects
OPTICAL properties, SEMICONDUCTOR nanocrystals, NANOCRYSTALS, CRYSTAL structure, OPTOELECTRONIC devices, QUANTUM dots, CRYSTALLINITY
Abstract

II–V semiconductor nanocrystals such as Cd3P2 and Zn3P2 have enormous potential as materials in next-generation optoelectronic devices requiring active optical properties across the visible and infrared range. To date, this potential has been unfulfilled due to their inherent instability with respect to air and moisture. Core-shell system Cd3P2/Zn3P2 is synthesized and studied from structural (morphology, crystallinity, shell diameter), chemical (composition of core, shell, and ligand sphere), and optical perspectives (absorbance, emission-steady state and time resolved, quantum yield, and air stability). The improvements achieved by coating with Zn3P2 are likely due to its identical crystal structure to Cd3P2 (tetragonal), highlighting the key role crystallographic concerns play in creating cutting edge core-shell NCs. [ABSTRACT FROM AUTHOR]

Published
2022
Full Text
View/download PDF

45. The category of 'probable class' to go beyond a Kanak/non- Kanak dichotomy

Author

Nayral, Mélissa, Laboratoire Interdisciplinaire Solidarités, Sociétés, Territoires (LISST), École des hautes études en sciences sociales (EHESS)-Université Toulouse - Jean Jaurès (UT2J)-École Nationale Supérieure de Formation de l'Enseignement Agricole de Toulouse-Auzeville (ENSFEA)-Centre National de la Recherche Scientifique (CNRS), École des hautes études en sciences sociales (EHESS)-Université Toulouse - Jean Jaurès (UT2J)-Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure de Formation de l'Enseignement Agricole de Toulouse-Auzeville (ENSFEA), and Nayral, Mélissa

Subjects
[SHS.ANTHRO-SE] Humanities and Social Sciences/Social Anthropology and ethnology, [SHS.ANTHRO-SE]Humanities and Social Sciences/Social Anthropology and ethnology, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2018

46. Conserver la biodiversité avec les ONG en Nouvelle-Calédonie: décolonisation ou délégation de gestion ?

Author

Marie Toussaint, Mélissa Nayral, Laboratoire Interdisciplinaire Solidarités, Sociétés, Territoires (LISST), and École des hautes études en sciences sociales (EHESS)-Université Toulouse - Jean Jaurès (UT2J)-Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure de Formation de l'Enseignement Agricole de Toulouse-Auzeville (ENSFEA)

Subjects
Nouvelle caledonie, Social Sciences and Humanities, aires protégées, Nouvelle-Calédonie, biodiversité, New Caledonia, Political science, GE1-350, ComputingMilieux_MISCELLANEOUS, lcsh:Environmental sciences, General Environmental Science, biodiversity, lcsh:GE1-350, gouvernance, conservation, NGO, [SHS.ANTHRO-SE]Humanities and Social Sciences/Social Anthropology and ethnology, décolonisation, Environmental sciences, governance, General Earth and Planetary Sciences, Sciences Humaines et Sociales, decolonization, protected areas, ONG, Humanities, Decolonization
Abstract

Ce texte interroge le rôle important que deux ONG environnementalistes, CI et WWF, ont été amenées à jouer dans le processus de définition et de gouvernance de deux aires protégées situées dans la province nord de la Nouvelle-Calédonie. Ce territoire océanien atypique de l’Outre-mer français au statut juridique unique, reconnue comme un hotspot de biodiversité (Myers et al., 2000) est en effet marqué par un contexte politique particulier de décolonisation négociée. Celui-ci, qui inclue des transferts de compétences depuis la France vers cette « ancienne colonie non-décolonisée » (Demmer et Salomon, 2013) a déjà permis l’émergence de la préservation de la biodiversité comme enjeu politique de premier plan. De manière concomitante à l’inscription des préoccupations environnementales dans les agendas internationaux, et comme dans d’autres territoires (Aubertin, 2005; Léna, 2002), plusieurs Organisations Non-Gouvernementales (ONG) de conservation ont par ailleurs graduellement contribué à la définition des politiques publiques environnementales locales. À partir de deux études de cas, ce texte montre les mécanismes par lesquels ces ONG ont d’abord pris part au processus de révision des anciens parcs et réserves naturels du territoire avant de devenir des interlocuteurs incontournables et partenaires privilégiés des institutions., This text questions the important role played by two major environmental NGOs, CI and WWF, in the process of defining and governing two protected areas located in the northern province of New Caledonia. With its unique legal status, this atypical Pacific territory of French overseas territories, now recognized as a hotspot for biodiversity (Myers et al., 2000), is indeed in the middle of a unique process of negotiated decolonization. This includes skills transfers from France to this "non-decolonized former colony" (Demmer and Salomon, 2013) that have already allowed the emergence of the preservation of biodiversity as a major political issue. With the concomitant inclusion of environmental concerns in international agendas, and very much like in other territories (Aubertin 2005, Léna 2002), several non-governmental conservation organizations (NGOs) have gradually contributed to the definition of environmental issues and local environmental public policies. Based on two case studies, this text shows the mechanisms by which these NGOs initially took part in the process of reviewing the former parks and natural reserves of the territory before becoming privileged partners of the local institutions.

Published
2020
Full Text
View/download PDF

47. Sustainable quantum dot chemistry: effects of precursor, solvent, and surface chemistry on the synthesis of Zn

Author

Robert A, Swain, Benjamin F P, McVey, Héloïse, Virieux, Fabio, Ferrari, Yann, Tison, Hervé, Martinez, Bruno, Chaudret, Céline, Nayral, and Fabien, Delpech

Abstract

The quest of exploring alternative materials for the replacement of toxic cadmium- and lead-based quantum dots (QDs) is necessary for envisaging a sustainable future but remains highly challenging. Tackling this issue, we present the synthesis of Zn3P2 nanocrystals (NCs) of unprecedented quality. New, reactive zinc precursors yield highly crystalline, colloidally stable particles, exhibiting oxide-free surfaces, size tunability and outstanding optical properties relative to previous reports of zinc phosphide QDs.

Published
2020

48. Sustainable quantum dot chemistry: effects of precursor, solvent, and surface chemistry on the synthesis of Zn 3 P 2 nanocrystals

Author

Fabio Ferrari, Héloïse Virieux, Benjamin F. P. McVey, Hervé Martinez, Fabien Delpech, Yann Tison, Robert A Swain, Céline Nayral, Bruno Chaudret, Laboratoire de physique et chimie des nano-objets (LPCNO), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC), Equipe MAD - Laboratoire GREYC - UMR6072, Groupe de Recherche en Informatique, Image et Instrumentation de Caen (GREYC), Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Normandie Université (NU)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU), Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux (IPREM), Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de chimie de coordination (LCC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Hétérochimie Fondamentale et Appliquée (LHFA), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Chimie de Toulouse (ICT-FR 2599), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie de Toulouse (ICT), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), and ANR-17-EURE-0009,NanoX,Science et Ingénierie à l'Echelle Nano(2017)

Subjects
chemistry.chemical_element, Nanotechnology, 02 engineering and technology, Zinc, 010402 general chemistry, 01 natural sciences, Catalysis, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, Materials Chemistry, Cadmium, Metals and Alloys, General Chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, equipment and supplies, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Solvent, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, [CHIM.POLY]Chemical Sciences/Polymers, chemistry, Nanocrystal, Quantum dot, Yield (chemistry), Ceramics and Composites, 0210 nano-technology
Abstract

International audience; The quest of exploring alternative materials for the replacement of toxic cadmium- and lead-based quantum dots (QDs) is necessary for envisaging a sustainable future but remains highly challenging. Tackling this issue, we present the synthesis of Zn3P2 nanocrystals (NCs) of unprecedented quality. New, reactive zinc precursors yield highly crystalline, colloidally stable particles, exhibiting oxide-free surfaces, size tunability and outstanding optical properties relative to previous reports of zinc phosphide QDs.

Published
2020
Full Text
View/download PDF

49. Medium effect on Cd3P2 quantum dots photoluminescence and addition of Pt nanoparticles: Inner filter effect and screening phenomena

Author

Céline Nayral, Xavier Marie, Fabien Delpech, Simon Tricard, Benjamin Chekroun, Gaëlle Muraille, Edwin A. Baquero, Bruno Chaudret, Delphine Lagarde, Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Universidad Nacional de Colombia [Bogotà] (UNAL), Optoélectronique Quantique (LPCNO), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC), and Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC)

Subjects
Materials science, Photoluminescence, Nanostructure, Biophysics, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, 7. Clean energy, Biochemistry, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, [CHIM.COOR]Chemical Sciences/Coordination chemistry, Quenching (fluorescence), General Chemistry, [CHIM.CATA]Chemical Sciences/Catalysis, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Atomic and Molecular Physics, and Optics, 0104 chemical sciences, Dilution, Full width at half maximum, Wavelength, [CHIM.POLY]Chemical Sciences/Polymers, Quantum dot, Chemical physics, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Filter effect, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], 0210 nano-technology
Abstract

International audience; The formation of complex nanostructures combining quantum dots (QDs) and metallic nanoparticles (NPs) opens new perspectives to study and control energy transfer between them, provided that all the phenomena (reabsorption, screening and quenching effect) potentially affecting the photoluminescence (PL) of QDs could be identified and differentiated. First, dilution effect is studied on Cd3P2 QDs and Cd3P2@ZnS core-shell QDs solutions. The full width at half maximum, the intensity and the emission wavelength are concentration-dependent, while the decay time of PL remains constant in the conditions of measurement. These effects are shown to be fully consistent with the so-called Inner Filter Effect. The addition of Pt NPs to the QD solution causes a clear decrease of the PL intensity which could be attributed to a screening of the emission of QDs by Pt NPs instead of a possible quenching due to an interaction between the two kinds of particles. Potential bias and experimental pitfalls are highlighted to avoid misleading PL interpretations.

Published
2020
Full Text
View/download PDF

50. Interfacial Oxidation and Photoluminescence of InP-Based Core/Shell Quantum Dots

Author

Edwin A. Baquero, Dorian Dupont, Valeriia Grigel, Sara Bals, Céline Nayral, Fabien Delpech, Mickael D. Tessier, Zeger Hens, Eva Bladt, Yannick Coppel, Universiteit Gent = Ghent University (UGENT), SIM vzw, Universidad Nacional de Colombia [Bogotà] (UNAL), Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Electron Microscopy for Materials Science - EMAT (Antwerp, Belgium), Universiteit Antwerpen = University of Antwerpen [Antwerpen], Laboratoire de chimie de coordination (LCC), Institut de Chimie de Toulouse (ICT), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Universiteit Gent = Ghent University [Belgium] (UGENT), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC), Universiteit Antwerpen [Antwerpen], Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), and Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Photoluminescence, General Chemical Engineering, Shell (structure), Oxide, 02 engineering and technology, 010402 general chemistry, 7. Clean energy, 01 natural sciences, chemistry.chemical_compound, Materials Chemistry, [CHIM.COOR]Chemical Sciences/Coordination chemistry, business.industry, Physics, Heterojunction, General Chemistry, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Core (optical fiber), Chemistry, chemistry, Quantum dot, Indium phosphide, Optoelectronics, 0210 nano-technology, Luminescence, business
Abstract

International audience; Indium phosphide colloidal quantum dots (QDs) are emerging as an efficient cadmium-free alternative for optoelectronic applications. Recently, syntheses based on easy-to-implement aminophosphine precursors have been developed. We show by solid-state nuclear magnetic resonance spectroscopy that this new approach allows oxide-free indium phosphide core or core/shell quantum dots to be made. Importantly, the oxide-free core/shell interface does not help in achieving higher luminescence efficiencies. We demonstrate that in the case of InP/ZnS and InP/ZnSe QDs, a more pronounced oxidation concurs with a higher photoluminescence efficiency. This study suggests that a II–VI shell on a III–V core generates an interface prone to defects. The most efficient InP/ZnS or InP/ZnSe QDs are therefore made with an oxide buffer layer between the core and the shell: it passivates these interface defects but also results in a somewhat broader emission line width.

Published
2018
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results