Quantifying Image Charge Effects in Molecular Tunnel Junctions Based on Self-Assembled Monolayers of Substituted Oligophenylene Ethynylene Dithiols
| Autor: | Olivier Galangau, Quyen Van Nguyen, C. Daniel Frisbie, Jérôme Cornil, Zuoti Xie, Lucie Norel, Sandra Rodriguez-Gonzalez, Stéphane Rigaut, Valentin Diez Cabanes |
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| Přispěvatelé: | Guangdong University of Technology, Technion - Israel Institute of Technology [Haifa], University of Minnesota System, University of Mons [Belgium] (UMONS), Universidad de Málaga [Málaga] = University of Málaga [Málaga], Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), C.D.F. acknowledges financial support from the U.S. National Science Foundation (CHE-2003199). Parts of this work were carried out in the Characterization Facility, University of Minnesota, which receives partial support from NSF through the MRSEC program (DMR-2011401). The work of S.R.G. has been supported by the Belgian National Fund for Scientific Research (F.R.S.-FNRS). We also acknowledge the Consortium des Équipements de Calcul Intensif (CÉCI) funded by F.R.S.-FNRSfor providing the computational resources. J.C. is an FNRS research director., Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA) |
| Rok vydání: | 2021 |
| Předmět: |
Materials science
image charge photoelectron spectroscopy 02 engineering and technology 010402 general chemistry Method of image charges 01 natural sciences Molecular physics symbols.namesake tunneling [CHIM]Chemical Sciences General Materials Science single level model HOMO/LUMO Quantum tunnelling Fermi level-HOMO offset Fermi level Self-assembled monolayer 021001 nanoscience & nanotechnology Potential energy charge transport 0104 chemical sciences Specific orbital energy symbols Density functional theory 0210 nano-technology molecular junction |
| Zdroj: | ACS Applied Materials & Interfaces ACS Applied Materials & Interfaces, 2021, 13 (47), pp.56404-56412. ⟨10.1021/acsami.1c16398⟩ ACS Applied Materials & Interfaces, Washington, D.C. : American Chemical Society, 2021, 13 (47), pp.56404-56412. ⟨10.1021/acsami.1c16398⟩ |
| ISSN: | 1944-8252 1944-8244 |
| Popis: | International audience; A number of factors contribute to orbital energy alignment with respect to the Fermi level in molecular tunnel junctions. Here, we report a combined experimental and theoretical effort to quantify the effect of metal image potentials on the highest occupied molecular orbital to Fermi level offset, ε(h), for molecular junctions based on self-assembled monolayers (SAMs) of oligophenylene ethynylene dithiols (OPX) on Au. Our experimental approach involves the use of both transport and photoelectron spectroscopy to extract the offsets, ε(h)(trans) and ε(h)(UPS), respectively. We take the difference in these quantities to be the image potential energy eV(image). In the theoretical approach, we use density functional theory (DFT) to calculate directly eV(image) between positive charge on an OPX molecule and the negative image charge in the Au. Both approaches yield eV(image) ∼ -0.1 eV per metal contact, meaning that the total image potential energy is ∼-0.2 eV for an assembled junction with two Au contacts. Thus, we find that the total image potential energy is 25-30% of the total offset ε(h), which means that image charge effects are significant in OPX junctions. Our methods should be generally applicable to understanding image charge effects as a function of molecular size, for example, in a variety of SAM-based junctions. |
| Databáze: | OpenAIRE |
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