Optical and morphological properties of thin films of bis-pyrenyl pi-conjugated molecules
| Autor: | Tobias Lünskens, Alain Ranguis, Frédéric Fages, Aras Kartouzian, Tony Lelaidier, Anthony D'Aléo, Alexander von Weber, Thomas Leoni, Ulrich Heiz, Conrad Becker |
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| Přispěvatelé: | Centre Interdisciplinaire de Nanoscience de Marseille (CINaM), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU), Technische Universität Munchen - Université Technique de Munich [Munich, Allemagne] (TUM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS) |
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Molecular diffusion
Absorption spectroscopy Chemistry Analytical chemistry General Physics and Astronomy 02 engineering and technology Substrate (electronics) [CHIM.MATE]Chemical Sciences/Material chemistry 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences ddc 0104 chemical sciences Amorphous solid [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry Crystallography Monolayer Microscopy Physical and Theoretical Chemistry Thin film 0210 nano-technology Spectroscopy |
| Zdroj: | Physical Chemistry Chemical Physics Physical Chemistry Chemical Physics, Royal Society of Chemistry, 2016, 18 (7), pp.5299-5305. ⟨10.1039/c5cp06011g⟩ Physical Chemistry Chemical Physics, 2016, 18 (7), pp.5299-5305. ⟨10.1039/c5cp06011g⟩ |
| ISSN: | 1463-9076 1463-9084 |
| DOI: | 10.1039/c5cp06011g⟩ |
| Popis: | International audience; 1,4-Di-n-octyloxy-2,5-bis(pyren-1-ylethenyl)benzene (bis-pyrene) has been studied by the means of surface cavity ring-down (s-CRD) spectroscopy on an amorphous BK7 glass substrate and scanning tunnelling microscopy (STM) on Au(111). Absorption spectra show a modification of the optical properties as a function of coverage, i.e. appearance of a shoulder around 505 nm followed by a saturation of the intensity of this signal observed at higher coverages. We attribute this shoulder to the change of the molecular orientation between the first and the second monolayer and thus to an interfacial effect. These results are confirmed by scanning tunnelling microscopy (STM) measurements where the bis-pyrene molecules have been deposited on Au(111) at room temperature (RT) and onto a cold substrate. Independently of the temperature in the range from 210 K to RT, the first monolayer is always highly organized. At low temperature bis-pyrene molecules constituting the second monolayer are randomly distributed, suggesting that self-organisation is kinetically hindered. Deposited at room temperature, the molecular diffusion is enhanced and the formation of an organized second layer takes place after storing the sample for 150 minutes at room temperature. A HOMO-LUMO gap of 2.85 eV has been determined by scanning tunnelling spectroscopy, which is in very good agreement with the observed optical transition at 434 nm (2.86 eV) in s-CRD spectroscopy. |
| Databáze: | OpenAIRE |
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