Frédéric Chérioux

University of Franche-Comté, Becoinson, Franche-Comté, France

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Publications (70)198.64 Total impact

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    ABSTRACT: The self-assembly of two-dimensional (2D) molecular structures on a solid surface relies on the subtle balance between noncovalent intermolecular and molecule–surface forces. The energetics of 2D molecular lattices forming different patterns on a passivated semiconductor surface are here investigated by a combination of atomistic simulation methods. Density-functional theory provides structure and charges of the molecules, while metadynamics with empirical forces provides a best guess for the lowest-energy adsorption sites of single molecules and dimers. Subsequently, molecular dynamics simulations of extended molecular assemblies with empirical forces yield the most favorable lattice structures at finite temperature and pressure. The theoretical results are in good agreement with scanning tunneling microscopy observations of self-assembled molecular monolayers on a B-doped Si(111) surface, thus allowing to rationalize the competition of long-range dispersion forces between the molecules and the surface. Such a result demonstrates the interest of this predictive approach for further progress in supramolecular chemistry on semiconductor surfaces.
    The Journal of Physical Chemistry C. 06/2014; 118(24):12817–12825.
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    ABSTRACT: Hydrogen and halogen bonds have been associated for the growth of 2D compact supramolecular networks on a silicon surface. These interactions have been elucidated in a complete monolayer of a 4,4''-dibromo-p-terphenyl (DBT) molecule on a Si(111)-B surface by combining scanning tunneling microscopy (STM) and density functional theory (DFT) calculations.
    Chemical Communications 04/2014; · 6.38 Impact Factor
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    ABSTRACT: The formation of large assemblies on the Si(111)-B surface is discussed with the help of STM simulations and DFT calculations. Although highly regular assemblies of DTB10B along the Si row direction are observed, the existence of two herringbone isomers introduces a lower periodicity within the 2D molecular network. The formation of herringbone units is explained by weak intermolecular interactions while the 1D assembling depends mainly on the interactions of the C10 side chains with the Si(111)-B surface.
    Chemical Communications 04/2014; · 6.38 Impact Factor
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    ABSTRACT: Thermally activated rotation of single molecules adsorbed on a silicon-based surface between 77 and 150 K has been successfully achieved. This remarkable phenomenon relies on a nanoporous supramolecular network, which acts as a template to seed periodic molecule rotors on the surface. Thermal activation of rotation has been demonstrated by STM experiments and confirmed by theoretical calculations.
    ChemPhysChem 02/2014; 15(2):271-5. · 3.35 Impact Factor
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    ABSTRACT: The design of working nanovehicles is a key challenge for the development of new devices. In this context, 1D controlled sliding of molecules on a silicon-based surface is successfully achieved by using an optimized molecule-substrate pair. Even though the molecule and surface are compatible, the molecule-substrate interaction provides a 1D template effect to guide molecular sliding along a preferential surface orientation. Molecular motion is monitored by STM experiments under ultra-high vacuum at room temperature. Molecule-surface interactions are elucidated by semi-empirical calculations.
    Nanoscale 06/2013; · 6.73 Impact Factor
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    ABSTRACT: The supramolecular self-assembly of brominated molecules was investigated and compared on Cu(110) and Cu(110)O(2×1) surfaces under ultrahigh vacuum. By using scanning tunnelling microscopy, we show that brominated molecules form a disordered structure on Cu(110), whereas a well-ordered supramolecular network is observed on the Cu(110)O(2×1) surface. The different adsorption behaviors of these two surfaces are described in terms of weakened molecule-substrate interactions on Cu(110)O(2×1) as opposed to bare Cu(110). The effect of oxygen-passivation is to suppress debromination and it can be a convenient approach for investigating other self-assembly processes on copper-based substrates.
    Chemistry - An Asian Journal 06/2013; · 4.57 Impact Factor
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    ABSTRACT: An open-and-shut case: By using tailored molecules, the formation of open or close-packed supramolecular network can be achieved on a silicon-based surface. The role of molecule-molecule interactions and molecule-substrate interactions to control the geometry of organic network on semi-conductor surface is investigated.
    ChemPhysChem 02/2013; · 3.35 Impact Factor
  • Matthieu Koepf, Frédéric Chérioux, Jennifer A. Wytko, Jean Weiss
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    ABSTRACT: In view of the many potential applications for functional hybrid interfaces, the controlled assembly of sophisticated structures on surfaces is a current challenge for chemists. Applications can be foreseen in fields such as molecular electronics, spintronics, sensors, catalysis and even synthesis. Independent of their functional nature, the characterization of nano-objects usually involves their deposition on surfaces. Whereas the formation of 2D networks on a surface corresponds to the association of scaffolds of the same dimensionality, 1D and 3D self-organized materials clearly differ from the 2D nature of the support. Unless necessary, organized 2D networks will not be examined in detail, as this subject has been periodically reviewed elsewhere. In this review, concepts originating from the 2D organization, but leading to the surface-assisted production of organized 1D and 3D self-assemblies will be examined and illustrated by selected recent examples from the literature.Three roles can be played by the surface. First, the surface can simply serve as an inert foundation for the organization of the functional layer, which is controlled by molecule–molecule interactions only. Second, the surface can be considered as a template by adding specific constraints to the assembly of the building blocks, restricting their conformational freedom and thus confining the growth in a surface plane or directing the growth of the nanostructures along specific symmetry axes (epitaxy) or surface defects and heterogeneities (step edges). This case seems the most conceptually advanced and has already led to integration of self-assembled materials into devices by using preferred orientations of the surface to align molecules in given directions, for example between interdigitated electrodes. Third, the surface itself can be a source of constituents, or adatoms, of the assembly and can alter the electronic structure of the building blocks, thus directly participating in the assembly process and final function of the structures. The latter case is more scarcely spread over different explorative works in which the major road maps are the successive growth of layers into three dimensions from a preorganized two dimensional (molecular) adlayer, as well as surface-induced reactions within an organized layer.
    Coordination Chemistry Reviews 12/2012; 256(s 23–24):2872–2892. · 11.02 Impact Factor
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    ABSTRACT: Two-dimensional supramolecular multicomponent networks on surfaces are of major interest for the building of highly ordered functional materials with nanometer-sized features especially designed for applications in nanoelectronics, energy storage, sensors, etc. If such molecular edifices have been previously built on noble metals or HOPG surfaces, we have successfully realized a 2D open supramolecular framework on a silicon adatom-based surface under ultrahigh vacuum with thermal stability up to 400 K by combining molecule-molecule and molecule-silicon substrate interactions. One of these robust open networks was further used to control both the growth and the periodicity of the first bicomponent arrays without forming any covalent bond with a silicon surface. Our strategy allows the formation of a well-controlled long-range periodic array of single fullerenes by site-specificity inclusion into a bicomponent supramolecular network.
    ACS Nano 06/2012; 6(8):6905-11. · 12.03 Impact Factor
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    ABSTRACT: The adsorption of zwitterionic molecules on Si(111)-7×7 substrates has been probed by scanning tunneling microscopy and spectroscopy and studied via density-functional-theory calculations. Experimental results obtained at room and low temperatures revealed the reconstruction of Si(111)-7×7 half-cells with molecular constructs accommodating three zwitterions. A structural model for the inscription of the Si(111)-7×7 half-cell with zwitterionic edifices is proposed and the nature of the interactions between the molecular assemblies and the surface is established thanks to joint experimental data and simulations.
    Physical review. B, Condensed matter 01/2012; 85(3). · 3.77 Impact Factor
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    ABSTRACT: We investigated the adsorption of 4-methoxy-4'-(3-sulfonatopropyl)stilbazolium (MSPS) on different ionic (001) crystal surfaces by means of noncontact atomic force microscopy. MSPS is a zwitterionic molecule with a strong electric dipole moment. When deposited onto the substrates at room temperature, MSPS diffuses to step edges and defect sites and forms disordered assemblies of molecules. Subsequent annealing induces two different processes: First, at high coverage, the molecules assemble into a well-organized quadratic lattice, which is perfectly aligned with the <110> directions of the substrate surface (i.e., rows of equal charges) and which produces a Moiré pattern due to coincidences with the substrate lattice constant. Second, at low coverage, we observe step edges decorated with MSPS molecules that run along the <110> direction. These polar steps most probably minimize the surface energy as they counterbalance the molecular dipole by presenting oppositely charged ions on the rearranged step edge.
    Beilstein Journal of Nanotechnology 01/2012; 3:285-93. · 2.37 Impact Factor
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    Angewandte Chemie International Edition 04/2011; 50(18):4094-8. · 11.34 Impact Factor
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    ABSTRACT: The formation of a large scale pattern on Si(111)-7 × 7 reconstruction is still a challenge. We report herein a new solution to achieve this type of nanostructuration by using of zwitterionic molecules. The formation of a large-scale pattern is successfully obtained due to the perfect match between the molecular geometry and the surface topology and to electrostatic interactions between molecules and surface. The adsorption is described by high-resolution scanning tunneling microscopy (STM) images and supported by density functional theory and STM calculations.
    ACS Nano 01/2011; 5(1):424-8. · 12.03 Impact Factor
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    ABSTRACT: A single 4-pyridylazobenzene molecule is observed at room temperature on a Si(111)-B surface by using scanning tunnel microscopy. The reversible conformational switching of this molecule is induced by tunneling electrons and observed at room temperature. This process is based on an intramolecular rotation of a single phenyl group without isomerization of the N=N double bond.
    ChemPhysChem 08/2010; 11(12):2568-72. · 3.35 Impact Factor
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    ABSTRACT: We report on the molecular assembly and local electronic properties of organic zwitterions deposited on the Si(111)-7x7 surface. We analyze these molecular systems by scanning tunneling microscopy and spectroscopy down to low temperatures. The molecules adsorb at specific sites on the Si(111)-7x7 surface, forming star-shaped configurations composed of three zwitterions filling up a half unit cell [1]. The regioselectivity of the process is determined by electrostatic interactions between the substrate and the ionic species, resulting in mirrored configurations in neighboring half unit cells. Thus, we probe chiral assemblies of achiral molecules on Si(111)-7x7 by spatially-resolved tunneling spectroscopy. For all investigated systems, ab initio simulations of the relaxed structures and local density of states are compared to experimental data. [1] Y. Makoudi et al., Surf. Sci. 602, 2719 (2008).
    03/2010;
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    ABSTRACT: Organic nanostructures on semiconductors are currently investigated due to their promising electronic properties. Deposition of trimesic acid molecules was achieved at room temperature on the Si(111)-7 × 7 surface. The adsorbed molecules adopt mainly two different arrangements observed by STM, which have been explained by two cumulative effects: (i) the match of the geometry of the molecule and the surface and (ii) the formation of three covalent bonds by the molecule with silicon adatoms of the surface. The adsorption conformation is presented and discussed by density functional theory calculations and by comparison with experimental STM results.
    Journal of Physical Chemistry C - J PHYS CHEM C. 02/2010; 114(10).
  • Mohamed El Garah, Frank Palmino, Frederic Cherioux
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    ABSTRACT: The formation of compact and large-scale self-assembled monolayers (SAMs) adsorbed on a mica surface has been achieved by insertion of alkyl chains on azobenzene derivatives, leading to strong intermolecular van der Waals interactions and hydrogen bonding. The reversible photoswitching of monolayers was investigated by monitoring the variation of the thickness of the SAMs during the cis-trans isomerization of the azobenzene cores with an atomic force microscope (AFM). The absence of covalent bonds between molecules and substrate induces a molecular diffusion which leads to the complete isomerization of the molecules constituting the SAMs.
    Langmuir 01/2010; 26(2):943-9. · 4.38 Impact Factor
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    ABSTRACT: A molecular machine can be basically defined as a single molecule which has been designed to perform mechanical-like movements responding to a specific stimulus. Molecular switches are one of the most investigated molecular machines. STM was successfully used to activate and/or investigate various dynamical processes of single molecules. Therefore, molecular switches adsorbed on surfaces are investigated by STM at the single molecular level, in the case of isolated molecules integrated in self- assembled alkane monolayers, or in the case of 2D supramolecular self-assemblies. However, all these remarkable results are mostly investigated on metal surfaces and at low temperature (<100 K). The reversible switching of a single molecule has been demonstrated on a silicon based surface at room temperature. The manipulation is induced by STM tip pulse voltage, leading to the switching between two enantiomers. The switching is controlled, reversible, and stable at room temperature. This is probably a new opportunity to store or to seed information at a molecular level on a surface by controlling (with a STM tip) the chirality of an adsorbate at room temperature.
    ChemPhysChem 01/2010; · 3.35 Impact Factor
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    ABSTRACT: Achievement of a large scale organic nano-structured pattern on semiconductors at room temperature is a major goal to realize molecular electronic nano-devices. To overcome the problem of the high reactivity of the Si surface versus electron-rich molecules, two main approaches were developed. All experiments were carried out by STM under high vacuum at variable temperature and by numerical simulations. The first approach consist in adsorption of original zwitterionic molecules on a Si(111)-7x7 reconstruction. The formation of a large scale pattern is successfully obtained thanks to the match of the molecular geometry with the surface topology and to electrostatic interactions between molecules and surface. The role of the temperature has been investigated by variable temperature STM experiments. The second strategy is based on a passivated silicon surface by inserting Boron atoms as doping element. The engineering of a complete organic adlayer by supramolecular self-assembly on a Si(111)-B √3x√3R30° surface at room temperature. This breakthrough has been achieved by using strong hydrogen bonds between pairs of dipolar molécules or halogen interactions between polyaromatic molecules.
    Elecmol'10. 01/2010;
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    ABSTRACT: The adsorption of zwitterionic (E) 4-methoxy-4′-(3-n-sulfonatopropyl)stilbazolium (MSPS) molecules on the stepped vicinal Au(23 23 21) surface was studied by scanning tunneling microscopy (STM) at low temperature as a function of the molecular coverage. At the sub-half monolayer, a supramolecular network based on MSPS is preferentially adsorbed onto face-centered cubic stacking regions. At the monolayer, a complete periodic supramolecular film is obtained.
    Surface Science 01/2010; · 1.84 Impact Factor

Publication Stats

117 Citations
198.64 Total Impact Points

Institutions

  • 2005–2014
    • University of Franche-Comté
      • Institut FEMTO-ST
      Becoinson, Franche-Comté, France
  • 2013
    • Centre d'Élaboration de Matériaux et d'Etudes Structurales (CERMES - CNRS)
      Tolosa de Llenguadoc, Midi-Pyrénées, France
  • 2004–2011
    • French National Centre for Scientific Research
      Lutetia Parisorum, Île-de-France, France
  • 2007
    • University of Nice-Sophia Antipolis
      Nice, Provence-Alpes-Côte d'Azur, France
  • 2001–2007
    • Université de Neuchâtel
      • • Institut de chimie (ICH)
      • • Laboratoire de chimie macromoléculaire
      Neuchâtel, NE, Switzerland