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Wagner MS, Peisert H, Chassé T, Bettinger HF. Detection of diheptacendiyl diradical intermediate in the cycloreversion of diheptacene to heptacene. Chem Commun (Camb) 2024; 60:8451-8453. [PMID: 39041191 DOI: 10.1039/d4cc03354j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/24/2024]
Abstract
Cycloreversion of diheptacenes, the covalently bound dimers of heptacene, in the solid state produces heptacene. In addition, diheptacendiyl diradical can be detected by ESR spectroscopy. The diradical has a small singlet-triplet energy gap of -0.02 kJ mol-1 (-4.8 × 10-3 kcal mol-1) in favor of the singlet state and is persistent in solid heptacene.
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Affiliation(s)
- Marie S Wagner
- Institute of Organic Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany.
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Heiko Peisert
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Thomas Chassé
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Holger F Bettinger
- Institute of Organic Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany.
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2
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Lerena L, Zuzak R, Godlewski S, Echavarren AM. The Journey for the Synthesis of Large Acenes. Chemistry 2024:e202402122. [PMID: 39077888 DOI: 10.1002/chem.202402122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Revised: 07/18/2024] [Accepted: 07/19/2024] [Indexed: 07/31/2024]
Abstract
Acenes, the group of polycyclic aromatic hydrocarbons (PAHs) with linearly fused benzene rings, possess distinctive electronic properties with potential applicability in material science. Hexacene was the largest acene obtained and characterized in the last century, followed by heptacene in 2006. Since then, a race for obtaining the largest acene resulted in the development of several members of this family as well as diverse innovative synthetic strategies, from solid-state chemistry to the promising on-surface chemistry. This last technique allows the obtention of large acenes, up to tridecacene, the largest acene so far. This review presents the different methodologies employed for the synthesis of acenes, highlighting the newest studies, to provide a much more thorough understanding of the essence of the electronic structure of this captivating group of organic compounds.
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Affiliation(s)
- Laura Lerena
- Institute of Chemical Research of Catalonia (ICIQ), CERCA, Barcelona Institute of Science and Technology, Av. Països Catalans 16, 43007, Tarragona, Spain
- Departament de Química Analítica i Química Orgànica, Universitat Rovira i Virgili, C/ Marcel⋅lí Domingo s/n, 43007, Tarragona, Spain
| | - Rafal Zuzak
- Centre for Nanometer-Scale Science and Advanced Materials, NANOSAM, Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, Lojasiewicza 11, PL 30-348, Krakow, Poland
| | - Szymon Godlewski
- Centre for Nanometer-Scale Science and Advanced Materials, NANOSAM, Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, Lojasiewicza 11, PL 30-348, Krakow, Poland
| | - Antonio M Echavarren
- Institute of Chemical Research of Catalonia (ICIQ), CERCA, Barcelona Institute of Science and Technology, Av. Països Catalans 16, 43007, Tarragona, Spain
- Departament de Química Analítica i Química Orgànica, Universitat Rovira i Virgili, C/ Marcel⋅lí Domingo s/n, 43007, Tarragona, Spain
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3
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Wagner MS, Peisert H, Chassé T, Hemberger P, Bettinger HF. Gas Phase Ionization Energy of Heptacene. J Phys Chem Lett 2024; 15:2332-2336. [PMID: 38386914 DOI: 10.1021/acs.jpclett.3c03580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2024]
Abstract
The ionization energy is a fundamental property that is relevant to charge transport in organic semiconductors. We report adiabatic ionization energies (AIEs) of heptacene at 6.21 and 7.20 eV for the X̃+B2g and Ã+Au states, respectively, as the next larger member of the acene series using mass- and isomer-selective double imaging photoelectron photoion coincidence spectroscopy. The X̃+ state energy decreases monotonically with an increase in size within the homologous series of acenes and approaches an asymptotic limit [AIE(polyacene) = 5.94 ± 0.06 eV] based on a fit with an exponential decay function. As byproducts of heptacene formation from cycloreversion of diheptacenes, 5,18-, 7,16-, and 6,17-dihydroheptacene can be detected, and their AIE is similar to that of their largest acene subunit (anthracene and tetracene, respectively), in very good agreement with computational treatments.
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Affiliation(s)
- Marie S Wagner
- Institut für Organische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
- Institut für Physikalische und Theoretische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Heiko Peisert
- Institut für Physikalische und Theoretische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Thomas Chassé
- Institut für Physikalische und Theoretische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Patrick Hemberger
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, CH-5232 Villigen-PSI, Switzerland
| | - Holger F Bettinger
- Institut für Organische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
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Boné T, Windischbacher A, Scheucher L, Presel F, Schnabl P, Wagner MS, Bettinger HF, Peisert H, Chassé T, Puschnig P, Ramsey MG, Sterrer M, Koller G. Orientation, electronic decoupling and band dispersion of heptacene on modified and nanopatterned copper surfaces. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 35:475003. [PMID: 37586386 DOI: 10.1088/1361-648x/acf105] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 08/16/2023] [Indexed: 08/18/2023]
Abstract
The adsorption of heptacene (7 A) on Cu(110) and Cu(110)-(2 × 1)-O was studied with scanning tunneling microscopy, photoemission orbital tomography and density functional calculations to reveal the influence of surface passivation on the molecular geometry and electronic states. We found that the charge transfer into the 7 A molecules on Cu(110) is completely suppressed for the oxygen-modified Cu surface. The molecules are aligned along the Cu-O rows and uncharged. They are tilted due to the geometry enforced by the substrate and the ability to maximize intermolecular π-π overlap, which leads to strong π-band dispersion. The HOMO-LUMO gap of these decoupled molecules is significantly larger than that reported on weakly interacting metal surfaces. Finally, the Cu-O stripe phase was used as a template for nanostructured molecular growth and to assess possible confinement effects.
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Affiliation(s)
- Thomas Boné
- Institute of Physics, University of Graz, NAWI Graz, Universitätsplatz 5, 8010 Graz, Austria
| | - Andreas Windischbacher
- Institute of Physics, University of Graz, NAWI Graz, Universitätsplatz 5, 8010 Graz, Austria
| | - Lukas Scheucher
- Institute of Physics, University of Graz, NAWI Graz, Universitätsplatz 5, 8010 Graz, Austria
| | - Francesco Presel
- Institute of Physics, University of Graz, NAWI Graz, Universitätsplatz 5, 8010 Graz, Austria
| | - Paul Schnabl
- Institute of Physics, University of Graz, NAWI Graz, Universitätsplatz 5, 8010 Graz, Austria
| | - Marie S Wagner
- Institute of Physical and Theoretical Chemistry, University of Tübingen, 72076 Tübingen, Germany
- Institute of Organic Chemistry, University of Tübingen, 72076 Tübingen, Germany
| | - Holger F Bettinger
- Institute of Organic Chemistry, University of Tübingen, 72076 Tübingen, Germany
| | - Heiko Peisert
- Institute of Physical and Theoretical Chemistry, University of Tübingen, 72076 Tübingen, Germany
| | - Thomas Chassé
- Institute of Physical and Theoretical Chemistry, University of Tübingen, 72076 Tübingen, Germany
| | - Peter Puschnig
- Institute of Physics, University of Graz, NAWI Graz, Universitätsplatz 5, 8010 Graz, Austria
| | - Michael G Ramsey
- Institute of Physics, University of Graz, NAWI Graz, Universitätsplatz 5, 8010 Graz, Austria
| | - Martin Sterrer
- Institute of Physics, University of Graz, NAWI Graz, Universitätsplatz 5, 8010 Graz, Austria
| | - Georg Koller
- Institute of Physics, University of Graz, NAWI Graz, Universitätsplatz 5, 8010 Graz, Austria
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Sättele MS, Windischbacher A, Greulich K, Egger L, Haags A, Kirschner H, Ovsyannikov R, Giangrisostomi E, Gottwald A, Richter M, Soubatch S, Tautz FS, Ramsey MG, Puschnig P, Koller G, Bettinger HF, Chassé T, Peisert H. Hexacene on Cu(110) and Ag(110): Influence of the Substrate on Molecular Orientation and Interfacial Charge Transfer. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2022; 126:5036-5045. [PMID: 35330758 PMCID: PMC8935373 DOI: 10.1021/acs.jpcc.2c00081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 02/15/2022] [Indexed: 06/14/2023]
Abstract
Hexacene, composed of six linearly fused benzene rings, is an organic semiconductor material with superior electronic properties. The fundamental understanding of the electronic and chemical properties is prerequisite to any possible application in devices. We investigate the orientation and interface properties of highly ordered hexacene monolayers on Ag(110) and Cu(110) with X-ray photoemission spectroscopy (XPS), photoemission orbital tomography (POT), X-ray absorption spectroscopy (XAS), low-energy electron diffraction (LEED), scanning tunneling microscopy (STM), and density functional theory (DFT). We find pronounced differences in the structural arrangement of the molecules and the electronic properties at the metal/organic interfaces for the two substrates. While on Cu(110) the molecules adsorb with their long molecular axis parallel to the high symmetry substrate direction, on Ag(110), hexacene adsorbs in an azimuthally slightly rotated geometry with respect to the metal rows of the substrate. In both cases, molecular planes are oriented parallel to the substrate. A pronounced charge transfer from both substrates to different molecular states affects the effective charge of different C atoms of the molecule. Through analysis of experimental and theoretical data, we found out that on Ag(110) the LUMO of the molecule is occupied through charge transfer from the metal, whereas on Cu(110) even the LUMO+1 receives a charge. Interface dipoles are determined to a large extent by the push-back effect, which are also found to differ significantly between 6A/Ag(110) and 6A/Cu(110).
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Affiliation(s)
- Marie S Sättele
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
- Institute of Organic Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Andreas Windischbacher
- Institute of Physics, University of Graz, NAWI Graz, Universitätsplatz 5, 8010 Graz, Austria
| | - Katharina Greulich
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Larissa Egger
- Institute of Physics, University of Graz, NAWI Graz, Universitätsplatz 5, 8010 Graz, Austria
| | - Anja Haags
- Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, 52425 Jülich, Germany
- Jülich Aachen Research Alliance (JARA), Fundamentals of Future Information Technology, 52425 Jülich, Germany
- Experimental Physics IV A, RWTH Aachen University, 52074 Aachen, Germany
| | - Hans Kirschner
- Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, 10587 Berlin, Germany
| | - Ruslan Ovsyannikov
- Institute for Methods and Instrumentation in Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Straße 15, 12489 Berlin, Germany
| | - Erika Giangrisostomi
- Institute for Methods and Instrumentation in Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Straße 15, 12489 Berlin, Germany
| | - Alexander Gottwald
- Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, 10587 Berlin, Germany
| | - Mathias Richter
- Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, 10587 Berlin, Germany
| | - Serguei Soubatch
- Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, 52425 Jülich, Germany
- Jülich Aachen Research Alliance (JARA), Fundamentals of Future Information Technology, 52425 Jülich, Germany
| | - F Stefan Tautz
- Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, 52425 Jülich, Germany
- Jülich Aachen Research Alliance (JARA), Fundamentals of Future Information Technology, 52425 Jülich, Germany
- Experimental Physics IV A, RWTH Aachen University, 52074 Aachen, Germany
| | - Michael G Ramsey
- Institute of Physics, University of Graz, NAWI Graz, Universitätsplatz 5, 8010 Graz, Austria
| | - Peter Puschnig
- Institute of Physics, University of Graz, NAWI Graz, Universitätsplatz 5, 8010 Graz, Austria
| | - Georg Koller
- Institute of Physics, University of Graz, NAWI Graz, Universitätsplatz 5, 8010 Graz, Austria
| | - Holger F Bettinger
- Institute of Organic Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Thomas Chassé
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
- Center for Light-Matter Interaction, Sensors & Analytics (LISA+), University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Heiko Peisert
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
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Belser A, Greulich K, Sättele MS, Fingerle M, Ovsyannikov R, Giangrisostomi E, Chassé T, Peisert H. Interface Properties of CoPc on Nanographene-Covered Au(111) and the Influence of Annealing. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:10750-10761. [PMID: 34464137 DOI: 10.1021/acs.langmuir.1c01438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Organic bilayer systems and heterostructures are of enormous importance for optoelectronic devices. We study interface properties and the structural ordering of cobalt phthalocyanine (CoPc) on a highly ordered monolayer hexa-peri-hexabenzocoronene (HBC), grown on Au(111), using photoemission, X-ray absorption, scanning tunneling microscopy, and low-energy electron diffraction. A charge transfer between CoPc and the gold substrate is almost completely prevented by the HBC intermediate layer. We show that HBC acts as a template for the initial growth of CoPc molecules. After annealing to 630 K, a molecular exchange takes place, resulting in a coexistence of domains of both CoPc and HBC molecules on the surface.
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Affiliation(s)
- Axel Belser
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, Tübingen 72076, Germany
| | - Katharina Greulich
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, Tübingen 72076, Germany
| | - Marie S Sättele
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, Tübingen 72076, Germany
- Institute of Organic Chemistry, University of Tübingen, Auf der Morgenstelle 18, Tübingen 72076, Germany
| | - Michael Fingerle
- Institute of Organic Chemistry, University of Tübingen, Auf der Morgenstelle 18, Tübingen 72076, Germany
| | - Ruslan Ovsyannikov
- Institute for Methods and Instrumentation in Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Straße 15, Berlin 12489, Germany
| | - Erika Giangrisostomi
- Institute for Methods and Instrumentation in Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Straße 15, Berlin 12489, Germany
| | - Thomas Chassé
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, Tübingen 72076, Germany
- Center for Light-Matter Interaction, Sensors & Analytics (LISA+) at the University of Tübingen, Auf der Morgenstelle 18, Tübingen 72076, Germany
| | - Heiko Peisert
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, Tübingen 72076, Germany
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Boné T, Windischbacher A, Sättele MS, Greulich K, Egger L, Jauk T, Lackner F, Bettinger HF, Peisert H, Chassé T, Ramsey MG, Sterrer M, Koller G, Puschnig P. Demonstrating the Impact of the Adsorbate Orientation on the Charge Transfer at Organic-Metal Interfaces. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2021; 125:9129-9137. [PMID: 34055126 PMCID: PMC8154845 DOI: 10.1021/acs.jpcc.1c01306] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 04/15/2021] [Indexed: 06/12/2023]
Abstract
Charge-transfer processes at molecule-metal interfaces play a key role in tuning the charge injection properties in organic-based devices and thus, ultimately, the device performance. Here, the metal's work function and the adsorbate's electron affinity are the key factors that govern the electron transfer at the organic/metal interface. In our combined experimental and theoretical work, we demonstrate that the adsorbate's orientation may also be decisive for the charge transfer. By thermal cycloreversion of diheptacene isomers, we manage to produce highly oriented monolayers of the rodlike, electron-acceptor molecule heptacene on a Cu(110) surface with molecules oriented either along or perpendicular to the close-packed metal rows. This is confirmed by scanning tunneling microscopy (STM) images as well as by angle-resolved ultraviolet photoemission spectroscopy (ARUPS). By utilizing photoemission tomography momentum maps, we show that the lowest unoccupied molecular orbital (LUMO) is fully occupied and also, the LUMO + 1 gets significantly filled when heptacene is oriented along the Cu rows. Conversely, for perpendicularly aligned heptacene, the molecular energy levels are shifted significantly toward the Fermi energy, preventing charge transfer to the LUMO + 1. These findings are fully confirmed by our density functional calculations and demonstrate the possibility to tune the charge transfer and level alignment at organic-metal interfaces through the adjustable molecular alignment.
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Affiliation(s)
| | | | - Marie S. Sättele
- Institute
of Physical and Theoretical Chemistry, University of Tübingen, 72076 Tübingen, Germany
- Institute
of Organic Chemistry, University of Tübingen, 72076 Tübingen, Germany
| | - Katharina Greulich
- Institute
of Physical and Theoretical Chemistry, University of Tübingen, 72076 Tübingen, Germany
| | - Larissa Egger
- Institute
of Physics, University of Graz, 8010 Graz, Austria
| | - Thomas Jauk
- Institute
of Experimental Physics, Graz University of Technology, 8010 Graz, Austria
| | - Florian Lackner
- Institute
of Experimental Physics, Graz University of Technology, 8010 Graz, Austria
| | - Holger F. Bettinger
- Institute
of Organic Chemistry, University of Tübingen, 72076 Tübingen, Germany
| | - Heiko Peisert
- Institute
of Physical and Theoretical Chemistry, University of Tübingen, 72076 Tübingen, Germany
| | - Thomas Chassé
- Institute
of Physical and Theoretical Chemistry, University of Tübingen, 72076 Tübingen, Germany
| | | | - Martin Sterrer
- Institute
of Physics, University of Graz, 8010 Graz, Austria
| | - Georg Koller
- Institute
of Physics, University of Graz, 8010 Graz, Austria
| | - Peter Puschnig
- Institute
of Physics, University of Graz, 8010 Graz, Austria
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