32 results on '"Ludovic Tortech"'
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2. In-Situ Energy Dispersive X-ray Reflectivity Applied to Polyoxometalate Films: An Approach to Morphology and Interface Stability Issues in Organic Photovoltaics
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Amanda Generosi, Marco Guaragno, Qirong Zhu, Anna Proust, Nicholas T. Barrett, Ludovic Tortech, and Barbara Paci
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time resolved EDXR ,in-situ X-ray characterization ,polyoxymetalate functional materials ,thin films structure and morphology ,organic photovoltaics ,Mathematics ,QA1-939 - Abstract
Organic solar cells, characterized by a symmetrical regular layered structure, are very promising systems for developing green, low cost, and flexible solar energy conversion devices. Despite the efficiencies being appealing (over 17%), the technological transfer is still limited by the low durability. Several processes, in bulk and at interface, are responsible. The quick downgrading of the performance is due to a combination of physical and chemical degradations. These phenomena induce instability and a drop of performance in working conditions. Close monitoring of these processes is mandatory to understand the degradation pathways upon device operation. Here, an unconventional approach based on Energy Dispersive X-ray Reflectivity (ED-XRR) performed in-situ is used to address the role of Wells–Dawson polyoxometalate (K6-P2W18O62, hereafter K6-P2W18) as hole transporting layer in organic photovoltaics. The results demonstrate that K6-P2W18 thin films, showing ideal bulk and interface properties and superior optical/morphological stability upon prolonged illumination, are attractive candidates for the interface of durable OPV devices.
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- 2020
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3. Conductivity via Thermally Induced Gap States in a Polyoxometalate Thin Layer
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Cindy L. Rountree, Amanda Generosi, Barbara Paci, Anna Proust, Qirong Zhu, Claire Mathieu, Nicholas Barrett, Guillaume Izzet, Pierre Gouzerh, Séverine Renaudineau, Ludovic Tortech, Xihui Liang, Institut Parisien de Chimie Moléculaire (IPCM), Chimie Moléculaire de Paris Centre (FR 2769), Institut de Chimie du CNRS (INC)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Consiglio Nazionale delle Ricerche [Roma] (CNR), Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), DIM NanoK, région Ile de France, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN UMR 3685), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR)
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Materials science ,Photoemission spectroscopy ,02 engineering and technology ,Conductivity ,010402 general chemistry ,7. Clean energy ,01 natural sciences ,Polyoxometalate Thin Layer ,Physical and Theoretical Chemistry ,Electrical conductor ,Deposition (law) ,business.industry ,Thermally Induced Gap- States ,[CHIM.MATE]Chemical Sciences/Material chemistry ,021001 nanoscience & nanotechnology ,Thermal conduction ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Characterization (materials science) ,General Energy ,Polyoxometalate ,Optoelectronics ,0210 nano-technology ,business ,Layer (electronics) - Abstract
International audience; We report a study of alpha-[P2W18O62]6-, Wells-Dawson polyoxometalate layers deposited on ITO coated glass substrates. A variety of techniques has been used including atomic force microscopy for surface topography characterization, current mapping and current-voltage characteristics, X-ray photoemission spectroscopy for chemical analysis, UV-visible photoemission spectroscopy for determination of band line-ups and energy dispersive X-ray reflectivity for determination of layer thicknesses and scattering length densities. The conditions of film deposition and subsequent thermal annealing strongly affect the film characteristics. In particular, we show that nanostriped films a few tens of nm thick can be obtained in a reproducible manner and that such structuring is accompanied by the appearance of gap-states and by a switch from an insulating to a conductive state. Current-voltage characteristics demonstrate that highly ordered films of K 6 [P 2 W 18 O 62 ] allow electron flow only from ITO to [P2W18O62]6-, thus showing a rectifying effect. Finally, we integrate the POM layer 2 into an organic photovoltaic device and show the conduction through it thanks to favorable band alignment between ITO, the gap states and the active photovoltaic layers.
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- 2019
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4. Electrical properties of iron corrosion layers formed in anoxic environments at the nanometer scale
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Delphine Neff, Florence Mercier-Bion, Hélène Lotz, Ludovic Tortech, Jiaying Li, Philippe Dillmann, Laboratoire Archéomatériaux et Prévision de l'Altération (LAPA - UMR 3685), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), IRAMAT - Laboratoire Métallurgies et Cultures (IRAMAT - LMC), Institut de Recherches sur les Archéomatériaux (IRAMAT), Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Montaigne-Université de Technologie de Belfort-Montbeliard (UTBM)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Montaigne-Université de Technologie de Belfort-Montbeliard (UTBM), Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN), Edifices PolyMétalliques (E-POM), Institut Parisien de Chimie Moléculaire (IPCM), Institut de Chimie du CNRS (INC)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université de Technologie de Belfort-Montbeliard (UTBM)-Université d'Orléans (UO)-Université Bordeaux Montaigne (UBM)-Centre National de la Recherche Scientifique (CNRS)-Université de Technologie de Belfort-Montbeliard (UTBM)-Université d'Orléans (UO)-Université Bordeaux Montaigne (UBM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN UMR 3685), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
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Materials science ,General Chemical Engineering ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Corrosion ,Metal ,chemistry.chemical_compound ,Iron corrosion ,General Materials Science ,FESEM ,Electrical conductor ,Magnetite ,C-AFM ,[CHIM.MATE]Chemical Sciences/Material chemistry ,General Chemistry ,Conductive atomic force microscopy ,021001 nanoscience & nanotechnology ,Anoxic waters ,0104 chemical sciences ,chemistry ,Chemical engineering ,visual_art ,Electrical properties ,visual_art.visual_art_medium ,Archaeological artefact ,Carbonate ,Nanometre ,µRaman ,0210 nano-technology - Abstract
International audience; The electrical properties of the corrosion layers on archaeological iron artefacts were determined by Conductive Atomic Force Microscopy. Different corrosion products were studied: Fe$^{II}$ carbonates, magnetite entrapped in the carbonate, and iron sulfides. The results indicate that the ferrous carbonate matrix is insulating, and that magnetite and iron sulfides have a conductive character, although these phases are not systematically connected to the metal. This suggests that electrons produced by the anodic dissolution of metal would be conducted to the external part of the corrosion product layer through a three-dimensional network of connected magnetite strips passing through the ferrous carbonate matrix.
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- 2018
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5. Towards complete band structure of microscopic MoS2 flakes
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Sergey Babenkov, Marie Froidevaux, Peng Ye, Ludovic Tortech, Yannick Dappe, Willem Boutu, Nickolas Barrett, and Hamed Merdji
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The occupied and unoccupied electronic states of MoS2 monolayer isolated flake were studied using laboratory based photoemission electron microscope (PEEM) nanoESCA equipped with He-I photon source. PEEM real-space imaging allowed selecting the high quality flake. Altogether, the data will allow accurately recovering the band structures of MoS2. The band structures will be used in future pump-probe experiments to explore the dynamics of electrons in the conduction band and photo-induced multitopological states using trefoil polarization.
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- 2022
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6. Controlling the magnetic exchange coupling in hybrid heterojunctions via spacer layers of π -conjugated molecules
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Alexander Smogunov, Pierre Bonville, Camille Blouzon, Dongzhe Li, Ludovic Tortech, Jean-Baptiste Moussy, Quentin Arnoux, Yannick J. Dappe, Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN UMR 3685), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut Parisien de Chimie Moléculaire (IPCM), Chimie Moléculaire de Paris Centre (FR 2769), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Nano-Magnétisme et Oxydes (LNO), Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Groupe Modélisation et Théorie (GMT), RTRA 'triangle de la Physique': project HeteroSpinMol, Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Institut de Chimie du CNRS (INC)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Service de physique de l'état condensé (SPEC - UMR3680), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
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Coupling ,Materials science ,Condensed matter physics ,Spintronics ,Heterojunction ,02 engineering and technology ,[CHIM.MATE]Chemical Sciences/Material chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,01 natural sciences ,Inductive coupling ,Magnetization ,Condensed Matter::Materials Science ,Ferromagnetism ,Ab initio quantum chemistry methods ,Condensed Matter::Superconductivity ,0103 physical sciences ,[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,Antiferromagnetism ,010306 general physics ,0210 nano-technology - Abstract
Mastering and understanding the magnetic couplings between magnetic electrodes separated by organic layers are crucial for developing new hybrid spintronic devices. We study the magnetic exchange interactions in organic-inorganic heterojunctions and unveil the possibility of controlling the strength of the magnetic exchange coupling between two ferromagnetic electrodes across $\ensuremath{\pi}$-conjugated molecules' ($\ensuremath{\alpha}$-sexithiophene or para-sexiphenyl) ultrathin film. In $\mathrm{F}{\mathrm{e}}_{3}{\mathrm{O}}_{4}/\ensuremath{\pi}$-conjugated molecules/Co magnetic tunnel junctions, an antiferromagnetic interlayer exchange coupling with variable strength is observed according to the nature of the aromatic rings (thiophene or phenyl groups). The underlying physical mechanism is revealed by ab initio calculations relating the strength of magnetic coupling to the spin moment penetration into a molecular layer at the molecule/Co interface. The prospect that magnetic coupling between two ferromagnetic electrodes can be mediated and tuned by organic molecules opens different perspectives in the way magnetization of organic tunnel junctions or spin valves can be driven.
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- 2019
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7. Interaction of low-energy electrons with surface polarity near ferroelastic domain boundaries
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M Pellen, D. Martinotti, Ekhard K. H. Salje, Raphael Haumont, Ludovic Tortech, Z. Zhao, Qiang Wu, Nicholas Barrett, Xi'an University of Technology (XUT), Laboratoire d'Etude des NanoStructures et Imagerie de Surface (LENSIS), Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire d'Electronique et nanoPhotonique Organique (LEPO), Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN UMR 3685), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), Université Paris-Sud - Paris 11 (UP11)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), University of Cambridge [UK] (CAM), Multi-disciplinary Materials Research Center, Frontier Institute of Science and Technology and State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, National Natural Science Foundation of China (Grant No. 51602255), Programs of Key Research and Development Plan of Shaanxi Province (Grant No. 2018ZDXM-GY-145), Scientific Research Program of Shaanxi Education Department (Grant No. 16JK1561), Doctoral Starting Fund of Xi’an University of Technology (Grant No. 101-451115016), Leverhulme Trust (Grant No. EM-2016-004), EPSRC (Grant No. EP/K009702/1), ANR-10-LABX-0035,Nano-Saclay,Paris-Saclay multidisciplinary Nano-Lab(2010), ANR-14-CE35-0019,HREELM,High resolution electron energy loss microscopy based on ionization of cold atoms: a new tool for surface nanochemistry(2014), Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Salje, Ekhard [0000-0002-8781-6154], and Apollo - University of Cambridge Repository
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Materials science ,Physics and Astronomy (miscellaneous) ,34 Chemical Sciences ,Polarity (physics) ,Flexoelectricity ,Ionic bonding ,02 engineering and technology ,Electron ,[CHIM.MATE]Chemical Sciences/Material chemistry ,021001 nanoscience & nanotechnology ,Ridge (differential geometry) ,01 natural sciences ,Molecular physics ,0103 physical sciences ,3406 Physical Chemistry ,[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,General Materials Science ,Surface charge ,010306 general physics ,0210 nano-technology ,Crystal twinning ,Electron scattering ,51 Physical Sciences - Abstract
International audience; We derive surface polarity at and near ferroelastic domain boundaries from molecular dynamics simulations based on an ionic spring model. Interatomic gradient forces lead to flexoelectricity which, in turn, generates polarity at the surface and in twin boundaries. We then derive generic properties of electron scattering spectra equivalent to those observed in low-energy electron microscopy (LEEM) and mirror electron microscopy (MEM) experiments. Negatively (positively) charged surfaces reflect (attract) incident electrons with low kinetic energy. The electron images reveal the valley and ridge surface structures near the intersection of the twin boundary and the surface. Polarity in surface layers is predicted to be visible in LEEM and MEM spectra at neutral surfaces, but much less when surfaces are charged. Inward polarity reflects electrons similar to negative surface charges, and outward polarity backscatters electrons like positive surface charges. Both the polarity in the twin boundary and the physical topography scatter electrons, consistent with experimental LEEM and MEM experiments on CaTiO3 with (001) and (111) surface terminations.
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- 2019
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8. Control of surface potential at polar domain walls in a nonpolar oxide
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Claire Mathieu, Jens Kreisel, D. Martinotti, Ludovic Tortech, Ekhard K. H. Salje, Pierre-Yves Hicher, Mael Guennou, Guillaume F. Nataf, Raphael Haumont, Nick Barrett, Oktay Aktas, Laboratoire d'Etude des NanoStructures et Imagerie de Surface (LENSIS), Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Luxembourg Institute of Science and Technology (LIST), Physics and Materials Science Research Unit, University of Luxemburg, Laboratoire de Physico-Chimie de l'Etat Solide (CHIMSOL), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Department of Earth Sciences [University of Cambridge], University of Cambridge [UK] (CAM), Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN UMR 3685), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut Parisien de Chimie Moléculaire (IPCM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Electronique et nanoPhotonique Organique (LEPO), Nataf, Guillaume [0000-0001-9215-4717], Salje, Ekhard [0000-0002-8781-6154], Apollo - University of Cambridge Repository, Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11), Department of Earth Sciences, University of Cambridge, Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut Rayonnement Matière de Saclay (IRAMIS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)
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Materials science ,Physics and Astronomy (miscellaneous) ,FOS: Physical sciences ,02 engineering and technology ,01 natural sciences ,Condensed Matter::Materials Science ,chemistry.chemical_compound ,Electric field ,0103 physical sciences ,Microelectronics ,General Materials Science ,010306 general physics ,[PHYS]Physics [physics] ,Condensed Matter - Materials Science ,Condensed matter physics ,business.industry ,Materials Science (cond-mat.mtrl-sci) ,021001 nanoscience & nanotechnology ,Polarization (waves) ,Ferroelectricity ,Piezoelectricity ,cond-mat.mtrl-sci ,Calcium titanate ,Ferromagnetism ,chemistry ,Polar ,0210 nano-technology ,business - Abstract
Ferroic domain walls could play an important role in microelectronics, given their nanometric size and often distinct functional properties. Until now, devices and device concepts were mostly based on mobile domain walls in ferromagnetic and ferroelectric materials. A less explored path is to make use of polar domain walls in nonpolar ferroelastic materials. Indeed, while the polar character of ferroelastic domain walls has been demonstrated, polarization control has been elusive. Here, we report evidence for the electrostatic signature of the domain-wall polarization in nonpolar calcium titanate (CaTiO3). Macroscopic mechanical resonances excited by an ac electric field are observed as a signature of a piezoelectric response caused by polar walls. On the microscopic scale, the polarization in domain walls modifies the local surface potential of the sample. Through imaging of surface potential variations, we show that the potential at the domain wall can be controlled by electron injection. This could enable devices based on nondestructive information readout of surface potential., Comment: 30 pages, 12 figures
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- 2017
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9. X-ray microscopic investigation of molecular orientation in a hole carrier thin film for organic solar cells
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Sufal Swaraj, Benjamin Watts, François Rochet, Quentin Arnoux, Ludovic Tortech, Laboratoire de Chimie Physique - Matière et Rayonnement (LCPMR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN UMR 3685), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut Parisien de Chimie Moléculaire (IPCM), Paul Scherrer Institute c/o Institute of Particle Physics, Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université Pierre et Marie Curie - Paris 6 (UPMC), Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Institut de Chimie du CNRS (INC)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Paul Scherrer Institute (PSI), Chimie Moléculaire de Paris Centre (FR 2769), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), and Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
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Materials science ,Organic solar cell ,Organic solar cells ,02 engineering and technology ,Substrate (electronics) ,Scanning transmission X-ray microscopy ,010402 general chemistry ,01 natural sciences ,Polymer solar cell ,Microscopy ,OLED ,General Materials Science ,Electrical and Electronic Engineering ,Thin film ,Scanning Transmission X-ray Microscopy ,business.industry ,[CHIM.MATE]Chemical Sciences/Material chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Evaporation (deposition) ,Atomic and Molecular Physics, and Optics ,Molecular orientation ,0104 chemical sciences ,Optoelectronics ,0210 nano-technology ,business ,[CHIM.OTHE]Chemical Sciences/Other - Abstract
International audience; As dipyranylidenes are excellent hole carriers, applications in organic solar cells or organic light emitting diode are envisaged. In the present study, we investigate the morphology of 2,2′,6,6′-tetraphenyl-4,4′-dipyranylidene (DIPO-Ph$_4$) deposited under vacuum on a silicon nitride (Si$_3$N$_4$) substrate, a paradigmatic system for the study of molecular crystal/inorganic substrate interfaces. Samples with various coating ratios and different thermal treatments were prepared. The films were characterized by atomic force microscopy and scanning transmission X-ray microscopy to gain insight into material growth. The results show a change in orientation at a molecular level depending upon the evaporation conditions. We are now able to tailor an organic layer with a specific molecular orientation and a specific electronic behavior.
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- 2017
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10. Structural and electronic properties of 2,2′,6,6′-tetraphenyl-dipyranylidene and its use as a hole-collecting interfacial layer in organic solar cells
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M. Alaaeddine, Marc Courté, Ludovic Tortech, Vincent Barth, Denis Fichou, School of Physical and Mathematical Sciences [Singapore], Nanyang Technological University [Singapour], Institut Parisien de Chimie Moléculaire (IPCM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN UMR 3685), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), and School of Physical and Mathematical Sciences
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Interfacial layers ,Materials science ,Organic solar cell ,Interfacial Layers ,Organic solar cells ,General Chemical Engineering ,Bulk heterojunction ,02 engineering and technology ,Substrate (electronics) ,010402 general chemistry ,Hole collection ,01 natural sciences ,7. Clean energy ,Atomic force microscopy ,PEDOT:PSS ,Thin film ,Photocurrent ,Organic Solar Cells ,business.industry ,Process Chemistry and Technology ,Heterojunction ,[CHIM.MATE]Chemical Sciences/Material chemistry ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Electrode ,Optoelectronics ,0210 nano-technology ,business ,Layer (electronics) - Abstract
The accumulation of positive charges at the anodic interface considerably limits the efficiency of photovoltaic solar cells based on polymer/fullerene bulk heterojunctions (BHJs). Interfacial layers (IFLs) such as PEDOT:PSS improve charge injection but have no effect on the unbalanced electron/hole transport across the BHJ. We report here the use of 2,2′,6,6′-tetraphenyl-dipyranylidene (DIPO-Ph4), a planar quinoïd compound, as an efficient anodic IFL in organic solar cells based on BHJs made of poly(3-hexylthiophene)/[6,6]-phenyl-C61-butyric-acid-methyl-ester (P3HT:PCBM). When deposited under vacuum onto a glass substrate, DIPO-Ph4 thin films are constituted of densely packed and vertically aligned crystalline needles. Current-sensing atomic force microscopy (CS-AFM) reveals a considerable increase of the hole-carrying pathways in DIPO-Ph4 thin films as compare to PEDOT:PSS, thus revealing their hole transporting/electron blocking properties. Inserting a 10 nm thick IFL of DIPO-Ph4 in combination with a 5 nm thick PEDOT:PSS between the ITO electrode and the P3HT:PCBM film leads to photocurrent densities up to 11.5 mA/cm2 under AM 1.5G and conversion efficiencies up to 4.6%, that is substantially higher than PEDOT:PSS-only devices. MOE (Min. of Education, S’pore)
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- 2017
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11. Enhancement of photovoltaic efficiency by insertion of a polyoxometalate layer at the anode of an organic solar cell
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Denis Fichou, Guillaume Izzet, Anna Proust, Nicholas Barrett, Julien E. Rault, Q. Zhu, M. Alaaeddine, Ludovic Tortech, Institut Parisien de Chimie Moléculaire (IPCM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN UMR 3685), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude des NanoStructures et Imagerie de Surface (LENSIS), Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut de Chimie du CNRS (INC)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut Rayonnement Matière de Saclay (IRAMIS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)
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Condensed Matter - Materials Science ,Materials science ,Organic solar cell ,Photovoltaic system ,Materials Science (cond-mat.mtrl-sci) ,FOS: Physical sciences ,Physics - Applied Physics ,Applied Physics (physics.app-ph) ,[CHIM.MATE]Chemical Sciences/Material chemistry ,7. Clean energy ,Polymer solar cell ,Anode ,Indium tin oxide ,Inorganic Chemistry ,X-ray photoelectron spectroscopy ,Chemical engineering ,Polyoxometalate ,Layer (electronics) - Abstract
In this article the Wells-Dawson polyoxometalate K6[P2W18O62] is grown as an interfacial layer between indium tin oxide and bulk heterojunction of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). The structure of the POM layers depends on the thickness and shows a highly anisotropic surface organization. The films have been characterized by atomic force microscopy and X-ray photoelectron spectroscopy (XPS) to gain insight into their macroscopic organization and better understand their electronic properties. Then, they were put at the anodic interface of a P3HT:PCBM organic solar cell and characterized on an optical bench. The photovoltaic efficiency is discussed in terms of the benefit of the polyoxometalate at the anodic interface of an organic photovoltaic cell., Comment: 7 pages, 6 figures
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- 2014
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12. Engineering the magnetic coupling and anisotropy at the molecule–magnetic surface interface in molecular spintronic devices
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Frédéric Miserque, Victoria E. Campbell, Marie-Anne Arrio, Nicolas Suaud, Ludovic Tortech, Richard Mattana, Yannick J. Dappe, Philippe Ohresser, Talal Mallah, Pierre Seneor, Fadi Choueikani, Anouk Galtayries, Irene Cimatti, Régis Guillot, Edwige Otero, Monica Tonelli, Philippe Sainctavit, Nathalie Guihéry, Jean-Baptiste Moussy, Eric Rivière, Vijay Gopal Chilkuri, Florian Koprowiak, Sophie Delprat, Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), Université Paris-Sud - Paris 11 (UP11)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Nano-Magnétisme et Oxydes (LNO), Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut Parisien de Chimie Moléculaire (IPCM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), THALES [France]-Centre National de la Recherche Scientifique (CNRS), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Systèmes étendus et magnétisme (LCPQ) (SEM), Laboratoire de Chimie et Physique Quantiques (LCPQ), 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)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-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)-Institut de Chimie du CNRS (INC), Institut de Recherche de Chimie Paris (IRCP), Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Ministère de la Culture (MC), Laboratoire d'Etude de la Corrosion Aqueuse (LECA), Service de la Corrosion et du Comportement des Matériaux dans leur Environnement (SCCME), Département de Physico-Chimie (DPC), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Département de Physico-Chimie (DPC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut de minéralogie et de physique des milieux condensés (IMPMC), Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Institut de Chimie du CNRS (INC)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-THALES [France], Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-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 Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), 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 du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Ministère de la Culture (MC), Université Pierre et Marie Curie - Paris 6 (UPMC)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), THALES-Centre National de la Recherche Scientifique (CNRS), 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), Centre National de la Recherche Scientifique (CNRS)-THALES, Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)
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Surface (mathematics) ,Materials science ,Science ,General Physics and Astronomy ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Article ,General Biochemistry, Genetics and Molecular Biology ,Condensed Matter::Materials Science ,Transition metal ,Ferrimagnetism ,Molecule ,Anisotropy ,ComputingMilieux_MISCELLANEOUS ,Multidisciplinary ,Spintronics ,Condensed matter physics ,General Chemistry ,equipment and supplies ,021001 nanoscience & nanotechnology ,Inductive coupling ,Transition metal ions ,0104 chemical sciences ,[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry ,Condensed Matter::Strongly Correlated Electrons ,0210 nano-technology ,human activities - Abstract
A challenge in molecular spintronics is to control the magnetic coupling between magnetic molecules and magnetic electrodes to build efficient devices. Here we show that the nature of the magnetic ion of anchored metal complexes highly impacts the exchange coupling of the molecules with magnetic substrates. Surface anchoring alters the magnetic anisotropy of the cobalt(II)-containing complex (Co(Pyipa)2), and results in blocking of its magnetization due to the presence of a magnetic hysteresis loop. In contrast, no hysteresis loop is observed in the isostructural nickel(II)-containing complex (Ni(Pyipa)2). Through XMCD experiments and theoretical calculations we find that Co(Pyipa)2 is strongly ferromagnetically coupled to the surface, while Ni(Pyipa)2 is either not coupled or weakly antiferromagnetically coupled to the substrate. These results highlight the importance of the synergistic effect that the electronic structure of a metal ion and the organic ligands has on the exchange interaction and anisotropy occurring at the molecule–electrode interface., Controlling the magnetic response of a molecular device is important for spintronic applications. Here the authors report the self-assembly, magnetic coupling, and anisotropy of two transition metal complexes bound to a ferrimagnetic surface, and probe the role of the nature of the transition metal ion.
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- 2016
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13. Dithiapyrannylidenes as Efficient Hole Collection Interfacial Layers in Organic Solar Cells
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Denis Fichou, Ludovic Tortech, Michelle Véber, and Stéphane Berny
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Materials science ,Fullerene ,Organic solar cell ,business.industry ,Photovoltaic system ,Oxide ,Heterojunction ,Space charge ,Anode ,chemistry.chemical_compound ,chemistry ,Electrode ,Optoelectronics ,General Materials Science ,business - Abstract
One inherent limitation to the efficiency of photovoltaic solar cells based on polymer/fullerene bulk heterojunctions (BHJs) is the accumulation of positive charges at the anodic interface. The unsymmetrical charge collection of holes and electrons dramatically decreases the short-circuit current. Interfacial layers (IFLs) such as poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) have no effect on the unbalanced electron/hole transport across the BHJ. We report here on the use of dithiapyrannylidenes (DITPY), a new class of planar quinoid compounds, as efficient hole-transporting/electron-blocking layers in organic solar cells based on poly(3-hexylthiophene)/[6,6]-phenyl-C(61)-butyric acid methyl ester (P3HT:PCBM) BHJs. Inserting a 15-nm-thick IFL of 4,4'-bis(diphenyl-2,6-thiapyrannylidene) (DITPY-Ph(4)) between the indium-tin oxide electrode and the P3HT:PCBM BHJ prevents detrimental space-charge effects and favors recombination-limited currents. Current-sensing atomic force microscopy reveals a drastic increase of the hole-carrying pathways in DITPY-Ph(4) compared to PEDOT:PSS. In ambient conditions, photovoltaic cells using DITPY-Ph(4) exhibit an 8% increase in the current density, although the conversion efficiency remains slightly lower compared to PEDOT:PSS-based devices. Finally, we present a detailed analysis of the photocurrent generation, showing that DITPY-Ph(4) IFLs induce a transition from unproductive space-charge-limited currents to recombination-limited currents.
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- 2010
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14. Tuning the Packing Density of 2D Supramolecular Self-Assemblies at the Solid−Liquid Interface Using Variable Temperature
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Ludovic Tortech, Klaus Müllen, Denis Fichou, Camille Marie, and Fabien Silly
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Phase transition ,Materials science ,General Engineering ,Supramolecular chemistry ,Analytical chemistry ,General Physics and Astronomy ,Substrate (electronics) ,Crystal engineering ,law.invention ,Sphere packing ,Chemical physics ,law ,General Materials Science ,Self-assembly ,Scanning tunneling microscope ,Phase diagram - Abstract
The two-dimensional (2D) crystal engineering of molecular architectures on surfaces requires controlling various parameters related respectively to the substrate, the chemical structure of the molecules, and the environmental conditions. We investigate here the influence of temperature on the self-assembly of hexakis(n-dodecyl)-peri-hexabenzocoronene (HBC-C(12)) adsorbed on gold using scanning tunneling microscopy (STM) at the liquid/solid interface. We show that the packing density of 2D self-assembled HBC-C(12) can be precisely tuned by adjusting the substrate temperature. Increasing the temperature progressively over the 20-50 degrees C range induces three irreversible phase transitions and a 3-fold increase of the packing density from 0.111 to 0.356 molecule/nm(2). High-resolution STM images reveal that this 2D packing density increase arises from the stepwise desorption of the n-dodecyl chains from the gold surface. Such temperature-controlled irreversible phase transitions are thus a versatile tool that can then be used to adjust the packing density of highly ordered functional materials in view of applications in organic electronic devices.
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- 2010
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15. Self-assembled monolayers of semifluorinated thiols on electrochemically modified polycrystalline nickel surfaces
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Serge Geribaldi, Frédéric Guittard, Zineb Mekhalif, Joseph Delhalle, and Ludovic Tortech
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chemistry.chemical_classification ,Chemistry ,Metals and Alloys ,Analytical chemistry ,chemistry.chemical_element ,Self-assembled monolayer ,Surfaces and Interfaces ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Contact angle ,Nickel ,X-ray photoelectron spectroscopy ,Transition metal ,Monolayer ,Polymer chemistry ,Materials Chemistry ,Thiol ,Cyclic voltammetry - Abstract
Electrochemically pretreated polycrystalline nickel substrates modified with ethanolic solutions (10 − 2 and 10 − 1 M) of four semi-fluorinated thiols with R F –R H –SH structures have been evaluated by X-ray photoelectron spectroscopy, contact angles and cyclic voltammetry measurements. Our results show that it is possible to graft highly fluorinated alkanethiols on nickel surfaces, the quality of the self assembled monolayers depending on the concentration of the dipping solutions, the dipping time as well as the length of the perfluorinated carbon chains and those of the hydrocarbon connector between the perfluorinated fragment and the thiol function.
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- 2005
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16. Synthesis and photovoltaic performances in solution-processed BHJs of oligothiophene-substituted organocobalt complexes [(η⁴-C₄(nT)₄)Co(η⁵-C₅H₅)]
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Guillaume H V, Bertrand, Ludovic, Tortech, Vincent, Gandon, Corinne, Aubert, and Denis, Fichou
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We describe an efficient synthetic route toward novel organocobalt complexes [(η(4)-C4(nT)4)Co(η(5)-C5H5)] with n = 1, 2, 3 thiophene rings. Solution-processed bulk heterojunctions solar cells based on CpCoCb(3T)4:PCBM blends achieve power conversion efficiencies of up to 2.1%.
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- 2014
17. The polar headgroup of the detergent governs the accessibility to water of tryptophan octyl ester in host micelles
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Béatrice de Foresta, Jacques Gallay, Michel Vincent, Ludovic Tortech, and Christine Jaxel
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Detergent micelle ,Surface Properties ,Phosphorylcholine ,Iodide ,Detergents ,Dodecylmaltoside ,Biophysics ,Quantum yield ,Micelle ,Biochemistry ,Fluorescence spectroscopy ,Polyethylene Glycols ,chemistry.chemical_compound ,Glucosides ,Octa(ethylene glycol) dodecyl monoether ,Collisional quencher ,Organic chemistry ,Micelles ,Fluorescent Dyes ,chemistry.chemical_classification ,Quenching (fluorescence) ,Molecular Structure ,Tryptophan octyl ester ,Tryptophan ,Membrane Proteins ,Water ,Cell Biology ,Hydrogen-Ion Concentration ,Dodecylphosphocholine ,Fluorescence ,Crystallography ,chemistry ,Acrylamide ,Anisotropy ,Ethylene glycol - Abstract
Many attempts have been made to rationalize the use of detergents for membrane protein studies [J. Biol. Chem. 264 (1989) 4907]. The barrier properties of the detergent headgroup may be one parameter critically involved in protein protection. In this paper, we analyzed these properties using a model system, by comparing the accessibility of tryptophan octyl ester (TOE) to water-soluble collisional quenchers (iodide and acrylamide) in three detergent micelles. The detergents used differed only in the chemical nature of their polar headgroups, zwitterionic for dodecylphosphocholine (DPC) and nonionic for octa(ethylene glycol) dodecyl monoether (C(12)E(8)) and dodecylmaltoside (DM). In all cases, in phosphate buffer at pH 7.5, the binding of 5 microM TOE was complete in the presence of a slight excess of detergent micelles over TOE molecules, resulting in a significant blue shift and greater intensity of TOE fluorescence emission. The resulting quantum yield of bound TOE was between 0.08 (in DPC) and 0.12 (in DM) with an emission maximum (lambda(max)) of approximately 335 nm whatever the detergent micelle. Time-resolved fluorescence intensity decays of TOE at lambda(max) were heterogeneous in all micelles (3-4 lifetime populations), with mean lifetimes of 1.7 ns in DPC, and 2 ns in both C(12)E(8) and DM. TOE fluorescence quenching by iodide, in detergent micelles, yielded linear Stern-Volmer plots characteristic of a dynamic quenching process. The accessibility of TOE to this ion was the greatest with C(12)E(8), followed by DPC and finally DM (Stern-Volmer quenching constants K(sv) of 2 to 5.5 M(-1)). In contrast, the accessibility of TOE to acrylamide was greatest with DPC, followed by C(12)E(8) and finally DM (K(sv)=2.7-7.1 M(-1)). TOE also presents less rotational mobility in DM than in the other two detergents, as shown from anisotropy decay measurements. These results, together with previous TOE quenching measurements with brominated detergents [Biophys. J. 77 (1999) 3071] provide reference data for analyzing Trp characteristics in peptide (and more indirectly protein)-detergent complexes. The main finding of this study was that TOE was less accessible (to soluble quenchers) in DM than in DPC and C(12)E(8), the cohesion of DM headgroup region being suggested to play a role in the ability of this detergent to protect function and stability of solubilized membrane proteins.
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- 2001
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18. Synthesis and photovoltaic performances in solution-processed BHJs of oligothiophene-substituted organocobalt complexes [(η4-C4(nT)4)Co(η5-C5H5)]
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Denis Fichou, Ludovic Tortech, Vincent Gandon, Corinne Aubert, Guillaume H. V. Bertrand, Institut Parisien de Chimie Moléculaire (IPCM), Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Méthodes et Application en Chimie Organique (MACO), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN UMR 3685), and Université Paris-Sud - Paris 11 (UP11)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
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Materials science ,02 engineering and technology ,010402 general chemistry ,7. Clean energy ,01 natural sciences ,Catalysis ,chemistry.chemical_compound ,Materials Chemistry ,Thiophene ,Organic chemistry ,[CHIM]Chemical Sciences ,ComputingMilieux_MISCELLANEOUS ,Photovoltaic system ,Metals and Alloys ,Heterojunction ,General Chemistry ,[CHIM.MATE]Chemical Sciences/Material chemistry ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Solution processed ,Chemical engineering ,chemistry ,Ceramics and Composites ,0210 nano-technology - Abstract
International audience; We describe an efficient synthetic route toward novel organocobalt complexes [([small eta]4-C4(nT)4)Co([small eta]5-C5H5)] with n = 1, 2, 3 thiophene rings. Solution-processed bulk heterojunctions solar cells based on CpCoCb(3T)4:PCBM blends achieve power conversion efficiencies of up to 2.1%.
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- 2014
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19. Anti-ferromagnetic coupling in hybrid magnetic tunnel junctions mediated by monomolecular layers of α-sexithiophene
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Camille Blouzon, Denis Fichou, Ludovic Tortech, F. Ott, Jean-Baptiste Moussy, Université Pierre et Marie Curie - Paris 6 - UFR de Médecine Pierre et Marie Curie (UPMC), Université Pierre et Marie Curie - Paris 6 (UPMC), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut Parisien de Chimie Moléculaire (IPCM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Nano-Magnétisme et Oxydes (LNO), Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay
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Coupling ,[PHYS]Physics [physics] ,Materials science ,Physics and Astronomy (miscellaneous) ,Spintronics ,Condensed matter physics ,Magnetometer ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Epitaxy ,01 natural sciences ,Inductive coupling ,law.invention ,Magnetization ,Nuclear magnetic resonance ,Ferromagnetism ,law ,0103 physical sciences ,Monolayer ,010306 general physics ,0210 nano-technology - Abstract
International audience; We report here on the magnetic coupling taking place between Fe3O4 and Co layers across an organic monolayer of α-sexithiophene (6T). The controlled growth of 6T ultrathin films on epitaxial Fe3O4 surfaces allows to prepare highly homogeneous insulating layers with thicknesses in the range 0.5–2.0 monolayers (ML). A combined study using vibrating sample magnetometry and polarized neutron reflectivity reveals that hybrid Fe3O4/6T/Co tunnel junctions show different magnetic couplings depending on the 6T thickness. In particular, magnetic coupling between Fe3O4 and Co layers separated by 1 ML of 6T is consistent with anti-ferromagnetic coupling, opening new perspectives for controlling magnetization in organic spintronic devices.
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- 2013
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20. X-ray photoelectron diffraction study of relaxation and rumpling of ferroelectric domains in BaTi$O_3$(001)
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Peixuan Chen, Cristian-Mihail Teodorescu, Jiale Wang, A. Pancotti, Nicholas Barrett, Emmanouil Frantzeskakis, Ludovic Tortech, Laboratoire d'Etude des NanoStructures et Imagerie de Surface (LENSIS), Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Johannes Kepler University Linz [Linz] (JKU), Service de Physique et de Chimie des Surfaces et Interfaces (SPCSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut Parisien de Chimie Moléculaire (IPCM), Institut de Chimie du CNRS (INC)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), National Institute of Materials Physics, Magurele-Ilfov, Romania, Synchrotron Soleil, DiffAbs beamline, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette Cedex, France (SYNCHROTRON SOLEIL, DIFFABS BEAMLINE, SAINT-AUBIN, BP 48, 91192 GIF-SUR-YVETTE CEDEX, FRANCE), Synchrotron Soleil, DiffAbs beamline, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette Cedex, France, The CEA-IFA MUTLIFERRODMS project, ANR-10-BLAN-1012,Surf-FER,Modifications de la structure chimique et électronique de surfaces ferroélectriques sous adsorption de H2O(2010), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Johannes Kepler Universität Linz - Johannes Kepler University Linz [Autriche] (JKU), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
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Diffraction ,[PHYS]Physics [physics] ,Materials science ,Scattering ,Relaxation (NMR) ,X-ray ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Ferroelectricity ,Electronic, Optical and Magnetic Materials ,Condensed Matter::Materials Science ,Crystallography ,Nuclear magnetic resonance ,PACS number(s): 73.22.Pr, 61.48.Gh, 79.60.−i ,X-ray photoelectron spectroscopy ,Electron diffraction ,0103 physical sciences ,010306 general physics ,0210 nano-technology ,Single crystal - Abstract
The surface of a ferroelectric BaTiO${}_{3}$(001) single crystal was studied using synchrotron radiation induced x-ray photoelectron diffraction (XPD), x-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and low-energy electron diffraction (LEED). AFM, XPS, and LEED show that the surface is BaO terminated with a (1$\ifmmode\times\else\texttimes\fi{}$1) reconstruction. The Ba $4d$, Ti $2p$, and O $1s$ XPD results were compared with multiple scattering simulations for out-of- (${\mathrm{P}}^{+},{\mathrm{P}}^{\ensuremath{-}}$) and in-plane (${\mathrm{P}}^{in}$) polarizations using a genetic algorithm to determine atomic rumpling and interlayer relaxation. Linear combinations of the XPD simulations of the surface structure of each polarization state allow determination of the domain ordering. The best agreement with experiment is found for 55$%$ ${\mathrm{P}}^{+}$, 38$%$ ${\mathrm{P}}^{\ensuremath{-}}$, and 7$%$ ${\mathrm{P}}^{in}$. The rumpling is smaller at the surface than in the bulk, suggesting that both domain ordering and surface structural changes contribute to screening of the polarization.
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- 2013
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21. An Improved Protocol for the Synthesis of [(η4-C4R4)Co(η5-C5H5)] Complexes
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Guillaume H. V. Bertrand, Denis Fichou, Corinne Aubert, Ludovic Tortech, Vincent Gandon, Max Malacria, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut Parisien de Chimie Moléculaire (IPCM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Institut de Chimie du CNRS (INC)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie des Substances Naturelles (ICSN), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN UMR 3685), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
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Dimethyl fumarate ,010405 organic chemistry ,Chemistry ,[CHIM.ORGA]Chemical Sciences/Organic chemistry ,Organic Chemistry ,Cyclohexadienes ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Inorganic Chemistry ,chemistry.chemical_compound ,Microwave irradiation ,Organic chemistry ,Reactivity (chemistry) ,Physical and Theoretical Chemistry - Abstract
International audience; The reaction of bulky alkynes C2R2 with (η5-C5H5)Co(CO)(dimethyl fumarate) under microwave irradiation provides complexes of the type [(η4-C4R4)Co(η5-C5H5)] in good to excellent yields. This protocol represents a significant improvement over those reported previously. In particular, the formation of insertion products such as cyclopentadienones or cyclohexadienes can be avoided. In addition, because of the exceptional stability of (η5-C5H5)Co(CO)(dimethyl fumarate), the reactions can be carried out in crude solvents. The easy access to [(η4-C4R4)Co(η5-C5H5)] complexes stimulated a study of their reactivity, notably under cross-coupling conditions.
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- 2012
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22. Ferroelectricity in a quasiamorphous ultrathin BaTiO3film
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Y. Y. Mi, Jiale Wang, Nicholas Barrett, A. Pancotti, Brice Gautier, Ludovic Tortech, S. Yin, P. Jégou, Gang Niu, and Bertrand Vilquin
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Diffraction ,Crystallography ,Materials science ,X-ray photoelectron spectroscopy ,Annealing (metallurgy) ,Microscopy ,Electronic structure ,Condensed Matter Physics ,Ferroelectricity ,Spectral line ,Electronic, Optical and Magnetic Materials ,Ion - Abstract
Until now, the quasiamorphous (QA) phase in ${\text{BaTiO}}_{3}$ (BTO), ${\text{SrTiO}}_{3}$ (STO), and ${\text{BaZrO}}_{3}$ was achieved by pulling a thick film through a steep temperature gradient. Here, we show that a room-temperature deposited ultrathin film, subsequently annealed in ${\text{O}}_{2}$ can also produce a QA phase. The atomic, electronic, and ferroelectric (FE) structure of a QA, ultrathin BTO grown on STO were studied by x-ray diffraction (XRD), x-ray photoelectron diffraction (XPD), x-ray photoelectron spectroscopy (XPS), and piezoforce microscopy (PFM). The absence of long-range order is confirmed by in- and out-of-plane XRD as well as Ti 2$p$ XPD. FE polarized domains with good retention have been successfully written into the QA film and exhibit a clear $P\ensuremath{-}E$ hysteresis loop. Substrate clamping frustrates volume expansion during annealing leading to a QA film. Photoelectron spectroscopy confirms a similar overall electronic structure as for thicker films but with some significant differences. Simple charge-transfer arguments are not sufficient to explain the high-resolution core-level spectra. Ba, Ti, and O all show components associated with a surface region. We suggest that the observation of such a component in the Ti 2$p$ spectrum is linked with the high dynamic charge tensor induced by the large off-center displacement of the Ti ion.
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- 2011
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23. Locking the free-rotation of a prochiral star-shaped guest molecule inside a two-dimensional nanoporous network by introduction of chlorine atoms
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Fabien Silly, Marie-Paule Teulade-Fichou, Hélène Bertrand, Ludovic Tortech, Denis Fichou, Conception, synthèse et vectorisation de biomolécules. (CSVB), Institut Curie-Centre National de la Recherche Scientifique (CNRS)-Université Paris Descartes - Paris 5 (UPD5), Service de Physique et de Chimie des Surfaces et Interfaces (SPCSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Université Pierre et Marie Curie - Paris 6 (UPMC), Université Paris Descartes - Paris 5 (UPD5)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Curie [Paris], and Université Paris Descartes - Paris 5 (UPD5)-Institut Curie [Paris]-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
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Chemistry ,Nanoporous ,[CHIM.ORGA]Chemical Sciences/Organic chemistry ,Chemical structure ,Chlorine atom ,Metals and Alloys ,Nanotechnology ,02 engineering and technology ,General Chemistry ,Star (graph theory) ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Catalysis ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Chemical physics ,Materials Chemistry ,Ceramics and Composites ,Honeycomb ,Molecule ,Symmetry breaking ,0210 nano-technology ,Free rotation - Abstract
International audience; Two star-shaped triazatrinaphthylene (TrisK) derivatives form highly-organized nanoporous honeycomb networks when adsorbed at the n-tetradecane/HOPG interface. STM reveals that replacing three H-atoms by three Cl-atoms in the chemical structure of the TrisK skeleton results in locking the free-rotation of the guest molecules inside the pore of the host network as a result of symmetry breaking.
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- 2011
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24. Location and dynamics of tryptophan in transmembrane alpha-helix peptides: a fluorescence and circular dichroism study
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Béatrice de Foresta, Jacques Gallay, Michel Vincent, and Ludovic Tortech
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Circular dichroism ,Stereochemistry ,Biophysics ,Peptide ,Micelle ,Sensitivity and Specificity ,Protein Structure, Secondary ,Glucosides ,Biomimetics ,Micelles ,chemistry.chemical_classification ,Quenching (fluorescence) ,Chemistry ,Circular Dichroism ,Methanol ,Tryptophan ,Membrane Proteins ,Water ,Membranes, Artificial ,General Medicine ,Fluorescence ,Transmembrane protein ,Spectrometry, Fluorescence ,Helix ,Anisotropy - Abstract
Amphiphilic and hydrophobic peptides play a key role in many biological processes. We have developed a reference system for evaluating the insertion of such peptides bearing Trp fluorescent reporter groups into membrane mimetic systems. This system involves a set of six 25-amino acid synthetic peptides that are models of transmembrane alpha-helices. They are Lys-flanked polyLeu sequences, each containing a single Trp residue at a different position (P i, with i=3, 5, 7, 9, 11 and 13). These peptides were inserted into micelles of a non-ionic detergent, dodecylmaltoside (DM). We analyzed this system by use of circular dichroism and steady-state and time-resolved fluorescence in combination with Trp quenching with two brominated DM analogs. We found significant variations in the Trp emission maximum according to its position in each peptide (from 327 to 313 nm). This is consistent with the radial insertion of the peptides within DM micelles. We observed characteristic patterns of fluorescence quenching of these peptides in mixed micelles of DM, with either 7,8-dibromododecylmaltoside (BrDM) or 10,11-dibromoundecanoylmaltoside (BrUM), that reflect differences in the accessibility of the Trp residue to the bromine atoms located on the detergent acyl chain. In the isotropic reference solvent, methanol, the alpha-helix content was high and identical (approximately 76%) for all peptides. In DM micelles, the alpha-helix content for P9 to P13 was similar to that in methanol, but slightly lower for P3 to P7. The fluorescence intensity decays were heterogeneous and depended upon the position of the Trp. The Trp dynamics of each peptide are described by sub-nanosecond and nanosecond rotational motions that were significantly lower than those observed in methanol. These results, which precisely describe structural, dynamic and microenvironment parameters of peptide Trp in micelles according to its depth, should be useful for describing the interactions of peptides of biological interest with micelles.
- Published
- 2001
25. Long-Range Alignments of Single Fullerenes by Site-Selective Inclusion into a Double-Cavity 2D Open Network
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Yohann Nicolas, Philippe Blanchard, Jean Roncali, Fabien Silly, Ludovic Tortech, Luc Piot, Denis Fichou, MOLTECH-Anjou, and Université d'Angers (UA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
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Range (particle radiation) ,Fullerene ,Chemistry ,Supramolecular chemistry ,Nanotechnology ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Biochemistry ,Catalysis ,0104 chemical sciences ,Trap (computing) ,Colloid and Surface Chemistry ,Chemical physics ,Site selective ,[CHIM]Chemical Sciences ,Molecule ,0210 nano-technology ,Host (network) - Abstract
International audience; We show by means of STM that C60 molecules can be trapped into specific sites of a 2D double-cavity open network, thus forming long-range alignments of single molecules. Since only one of the two cavities has the right size to host C60, the smallest cavity remains empty and is thus available to trap additional species of smaller size. This novel 2D supramolecular network opens new perspectives in the design of multicomponent guest?host architectures with electronic functionalities.
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- 2009
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26. Organic-inorganic magnetic tunnel heterojunctions based on dithiapyrannylidene ultrathin films grown on Fe3O4(111)
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Jean-Baptiste Moussy, Denis Fichou, Sylvia Matzen, Ludovic Tortech, and Stéphane Berny
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Materials science ,Physics and Astronomy (miscellaneous) ,business.industry ,Magnetometer ,Analytical chemistry ,Heterojunction ,Epitaxy ,Thermal conduction ,law.invention ,Planar ,law ,Electrode ,Optoelectronics ,business ,Quantum tunnelling ,Decoupling (electronics) - Abstract
We report on the morphology, transport, and magnetic properties of ultrathin films of 4,4′-bis(diphenyl-2,6-thiapyrannylidene) (DITPY-Ph4), a planar quinoid organic compound with potential applications in electronics. Atomic force microscopy (AFM) shows that highly homogeneous and continuous DITPY-Ph4 ultrathin films with thicknesses as low as 2 nm can be grown on epitaxial Fe3O4(111). Current-sensing AFM performed on ultrathin layers evidences an insulating behavior with a nonresonant tunneling conduction regime. Vibrating sample magnetometry achieved on Fe3O4/DITPY-Ph4/Co organic-inorganic heterojunctions reveals the decoupling between the two magnetic electrodes and demonstrates that DITPY-Ph4 can be used to build magnetic tunnel junctions.
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- 2010
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27. Growth and magnetic behavior in hybrid organic–inorganic Ferrite/Alq3/Co heterostructures
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Frédéric Ott, Marie-Joseph Guittet, Jean-Baptiste Moussy, Florentin Rengnez, Denis Fichou, Sylvia Matzen, and Ludovic Tortech
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Spintronics ,business.industry ,Chemistry ,Mineralogy ,Heterojunction ,General Chemistry ,Surface finish ,Organic inorganic ,Electrode ,Materials Chemistry ,Optoelectronics ,Ferrite (magnet) ,Nanometre ,business ,Decoupling (electronics) - Abstract
We report the growth and magnetic properties of AFe2O4/Alq3/Co heterostructures (AFe, Co) containing a continuous Alq3 thin layer with a low roughness, down to a few nanometers, and we demonstrate the magnetic decoupling between AFe2O4 and Co electrodes showing the interest of these systems for spintronics devices.
- Published
- 2009
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28. An Improved Protocol forthe Synthesis of [(η4-C4R4)Co(η5-C5H5)] Complexes.
- Author
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Guillaume Bertrand, Ludovic Tortech, Denis Fichou, Max Malacria, Corinne Aubert, and Vincent Gandon
- Subjects
- *
COMPLEX compounds synthesis , *METAL complexes , *ORGANOCOBALT compounds , *ALKYNES , *CHEMICAL reactions , *MICROWAVES , *CYCLOPENTADIENE , *REACTIVITY (Chemistry) - Abstract
The reaction of bulky alkynes C2R2with (η5-C5H5)Co(CO)(dimethylfumarate) undermicrowave irradiation provides complexes of the type [(η4-C4R4)Co(η5-C5H5)] in good to excellent yields. This protocol representsa significant improvement over those reported previously. In particular,the formation of insertion products such as cyclopentadienones orcyclohexadienes can be avoided. In addition, because of the exceptionalstability of (η5-C5H5)Co(CO)(dimethylfumarate), the reactions can be carried out in crude solvents. Theeasy access to [(η4-C4R4)Co(η5-C5H5)] complexes stimulated a studyof their reactivity, notably under cross-coupling conditions. [ABSTRACT FROM AUTHOR]
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- 2012
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29. Growth and magnetic behavior in hybrid organic–inorganic Ferrite/Alq3/Co heterostructures.
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Jean-Baptiste Moussy, Ludovic Tortech, Florentin Rengnez, Sylvia Matzen, Frédéric Ott, Marie-Joseph Guittet, and Denis Fichou
- Abstract
We report the growth and magnetic properties of AFe2O4/Alq3/Co heterostructures (AFe, Co) containing a continuous Alq3thin layer with a low roughness, down to a few nanometers, and we demonstrate the magnetic decoupling between AFe2O4and Co electrodes showing the interest of these systems for spintronics devices. [ABSTRACT FROM AUTHOR]
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- 2009
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30. A new mixed organic layer for enhanced corrosion protection of electric contacts
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Sophie Noël, Frédéric Guittard, Ludovic Tortech, Zineb Mekhalif, A. Di Meo, Joseph Delhalle, David Alamarguy, Nicole Lecaude, Laurent Tristani, Fabrice Laffineur, Serge Geribaldi, and Piero Gavezotti
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Metal ,Cable gland ,Materials science ,visual_art ,Metallurgy ,Contact resistance ,visual_art.visual_art_medium ,Molecule ,Cohesion (chemistry) ,Surface energy ,Electrical contacts ,Corrosion - Abstract
A large collaboration among different laboratories involving electrical engineering, surface chemistry and organic chemistry has been set up in a European program (5FP, project: 10622). It has allowed to develop a new type of organic layer on metallic surfaces with outstanding results in the field of protection against corrosion. Application to low level electrical contacts is very promising. Several types of highly fluorinated molecules have been specially synthesised and selected in order to build up a compact protective layer. Various techniques were used to characterise these films; their bonding to the substrate, their cohesion, their surface energies were analysed and the results were correlated to their corrosion properties. This led to the elaboration of a new type of layer with outstanding features. We report here the main results with emphasis on the results of the atmospheric corrosion test performed both on gold plated coupons and connector terminals. In this latter case the test comprises contact resistance measurements at various stages. We show how a suitable formulation allows to obtain low contact resistance values and low corrosion.
31. Physical chemistry of the TiN/Hf 0.5 Zr 0.5 O 2 interface
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Uwe Schroeder, Thomas Mikolajick, Nicholas Barrett, Ludovic Tortech, Christophe Lubin, A. Pancotti, W. Hamouda, Claudia Richter, Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude des NanoStructures et Imagerie de Surface (LENSIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN UMR 3685), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), NaMLab gGmbH, Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Institut Parisien de Chimie Moléculaire (IPCM), Chimie Moléculaire de Paris Centre (FR 2769), Institut de Chimie du CNRS (INC)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), ANR-11-EQPX-0005,ATTOLAB,Plateforme pour la dynamique attoseconde(2011), European Project: 780302,EC | H2020 | RIA,3eFERRO(2018), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), and Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
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010302 applied physics ,[PHYS]Physics [physics] ,Materials science ,Annealing (metallurgy) ,Schottky barrier ,Doping ,General Physics and Astronomy ,chemistry.chemical_element ,02 engineering and technology ,Conductive atomic force microscopy ,[CHIM.MATE]Chemical Sciences/Material chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Photoemission electron microscopy ,X-ray photoelectron spectroscopy ,chemistry ,0103 physical sciences ,Physical chemistry ,[CHIM]Chemical Sciences ,Thin film ,0210 nano-technology ,Tin ,ComputingMilieux_MISCELLANEOUS - Abstract
International audience; Ferroelectric hafnia-based thin films are promising candidates for emerging high-density embedded nonvolatile memory technologies, thanks to their compatibility with silicon technology and the possibility of 3D integration. The electrode–ferroelectric interface and the crystallization annealing temperature may play an important role in such memory cells. The top interface in a TiN/Hf0.5Zr0.5O2/TiN metal–ferroelectric–metal stack annealed at different temperatures was investigated with X-ray photoelectron spectroscopy. The uniformity and continuity of the 2 nm TiN top electrode was verified by photoemission electron microscopy and conductive atomic force microscopy. Partial oxidation of the electrode at the interface is identified. Hf is reduced near the top interface due to oxygen scavenging by the top electrode. The oxygen vacancy (VO) profile showed a maximum at the top interface (0.71%) and a sharp decrease into the film, giving rise to an internal field. Annealing at higher temperatures did not affect the VO concentration at the top interface but causes the generation of additional VO in the film, leading to a decrease of the Schottky Barrier Height for electrons. The interface chemistry and n-type film doping are believed to be at the origin of several phenomena, including wake-up, imprint, and fatigue. Our results give insights into the physical chemistry of the top interface with the accumulation of defective charges acting as electronic traps, causing a local imprint effect. This may explain the wake-up behavior as well and also can be a possible reason of the weaker endurance observed in these systems when increasing the annealing temperature
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32. Electronic and structural characterizations of a transparent conductive oxide/organic interface: Towards applications for organic electronic devices
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Arnoux, Quentin, Laboratoire de Chimie Physique - Matière et Rayonnement (LCPMR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris VI, François Rochet, Ludovic Tortech, Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université Pierre et Marie Curie - Paris 6 (UPMC), Institut Parisien de Chimie Moléculaire (IPCM), Institut de Chimie du CNRS (INC)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), and UPMC - Paris 6 Sorbonne Universités
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molecular orientation ,hole-transport layer ,photoemission spectroscopy ,Orientation moléculaire ,Transporteur de trous ,Interface métal/organique ,organic solar cells ,Charge transfer ,interfacial layer ,Organic solar cell ,Cellule solaire organique ,Transfert de charge ,Metal/organic interface ,[PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph] ,Spectroscopie de photoémission - Abstract
The energy level alignment of hole-transport organic molecular solids with indium tin oxide (ITO), a transparent conducting oxide, has been characterized. The studied molecules, based on the dipyranylidene (DIP) structure, differ by the heteroatom (O, S and Se). Synchrotron photoemission electron spectroscopy has been used to determine the alignment, and we investigated the molecular orientation via X-ray absorption spectromicroscopy. By interpreting spectroscopic data in the light of DFT calculations, we found evidence of the presence of charge transfer from the molecules to the ITO, when they are in intimate contact with the substrate, at least for the O and S-DIPs. The hole injection barrier between the ITO Fermi level and the organic HOMO was obtained. Our experimental approach emphasizes the relationship between structural and electronic properties. These results were obtained during beamtimes in France (SOLEIL), Italy (ELETTRA) and Switzerland (SLS).; Nous avons déterminé l'alignement des niveaux énergétiques d’un solide moléculaire organique, transporteurs de trous, avec un oxyde d'indium dopé à l’étain (ITO), un conducteur transparent. Les molécules étudiées, basées sur une structure dipyranylidène (DIP), diffèrent par leur hétéroatome (O, S et Se). La spectroscopie de photoémission X a été utilisée pour déterminer cet alignement, et nous avons étudié l'orientation moléculaire par spectromicroscopie d'absorption X. Des calculs DFT ont été réalisés pour interpréter les données spectroscopiques. Nous avons constaté la présence d'un transfert de charge, au moins pour les dérivés oxygénés et soufrés. Celui-ci a lieu des molécules vers l’ITO, lorsqu'ils sont en contact intime avec le substrat. Nous avons déterminé la barrière d'injection des trous entre le niveau de Fermi de l’ITO et la HOMO du solide organique. Notre approche expérimentale met l'accent sur la relation entre les propriétés structurelles et les propriétés électroniques. Ces résultats ont été obtenus pendant des runs synchroton en France (SOLEIL), en Italie (ELETTRA) et en Suisse (SLS).
- Published
- 2017
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