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Wagner T, Györök M, Wolfmayr S, Gründlinger P, Monkowius U, Zeppenfeld P. Aurophilic Molecules on Surfaces. Part II. (NapNC)AuCl on Au(111). ACS OMEGA 2023; 8:38083-38091. [PMID: 37867682 PMCID: PMC10586446 DOI: 10.1021/acsomega.3c04152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 09/18/2023] [Indexed: 10/24/2023]
Abstract
Although aurophilicity is a well-known phenomenon in structural gold chemistry and is found in many crystals of Au(I) complexes, its potential for self-assembly in thin films is not yet explored. This paper is Part II of a study, in which we investigated the ultrathin film formation of chlorido(2-naphthyl isonitrile) gold(I) on gold surfaces. Here, we present the data for the growth of (NapNC)AuCl on isotropic Au(111) surfaces. Already during physical vapor deposition, the condensation of ultrathin films is monitored by photoelectron emission microscopy (PEEM) and incremental and spectrally resolved changes in the optical reflectance (DDRS). Additional structural data obtained by scanning tunneling microscopy (STM) and low-energy electron diffraction (LEED) reveal that the "crossed swords" packing motif known from the bulk is also present in thin films.
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Affiliation(s)
- Thorsten Wagner
- Institute
of Experimental Physics, Surface Science Division, Johannes Kepler University, Altenberger Straße 69, 4040 Linz, Austria
| | - Michael Györök
- Institute
of Experimental Physics, Surface Science Division, Johannes Kepler University, Altenberger Straße 69, 4040 Linz, Austria
| | - Sebastian Wolfmayr
- Institute
of Experimental Physics, Surface Science Division, Johannes Kepler University, Altenberger Straße 69, 4040 Linz, Austria
| | - Petra Gründlinger
- Institute
of Experimental Physics, Surface Science Division, Johannes Kepler University, Altenberger Straße 69, 4040 Linz, Austria
| | - Uwe Monkowius
- School
of Education, Chemistry, Johannes Kepler
University, Altenberger
Straße 69, 4040 Linz, Austria
| | - Peter Zeppenfeld
- Institute
of Experimental Physics, Surface Science Division, Johannes Kepler University, Altenberger Straße 69, 4040 Linz, Austria
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Tomei I, Bonanni B, Sgarlata A, Fanfoni M, Martini R, Di Filippo I, Magna G, Stefanelli M, Monti D, Paolesse R, Goletti C. Chiral Porphyrin Assemblies Investigated by a Modified Reflectance Anisotropy Spectroscopy Spectrometer. Molecules 2023; 28:molecules28083471. [PMID: 37110705 PMCID: PMC10142836 DOI: 10.3390/molecules28083471] [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: 03/08/2023] [Revised: 04/06/2023] [Accepted: 04/07/2023] [Indexed: 04/29/2023] Open
Abstract
Reflectance anisotropy spectroscopy (RAS) has been largely used to investigate organic compounds: Langmuir-Blodgett and Langmuir-Schaeffer layers, the organic molecular beam epitaxy growth in situ and in real time, thin and ultrathin organic films exposed to volatiles, in ultra-high vacuum (UHV), in controlled atmosphere and even in liquid. In all these cases, porphyrins and porphyrin-related compounds have often been used, taking advantage of the peculiar characteristics of RAS with respect to other techniques. The technical modification of a RAS spectrometer (CD-RAS: circular dichroism RAS) allows us to investigate the circular dichroism of samples instead of the normally studied linear dichroism: CD-RAS measures (in transmission mode) the anisotropy of the optical properties of a sample under right and left circularly polarized light. Although commercial spectrometers exist to measure the circular dichroism of substances, the "open structure" of this new spectrometer and its higher flexibility in design makes it possible to couple it with UHV systems or other experimental configurations. The importance of chirality in the development of organic materials (from solutions to the solid state, as thin layers deposited-in liquid or in vacuum-on transparent substrates) could open interesting possibilities to a development in the investigation of the chirality of organic and biological layers. In this manuscript, after the detailed explanation of the CD-RAS technique, some calibration tests with chiral porphyrin assemblies in solution or deposited in solid film are reported to demonstrate the quality of the results, comparing curves obtained with CD-RAS and a commercial spectrometer.
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Affiliation(s)
- Ilaria Tomei
- Department of Physics, Università di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Roma, Italy
| | - Beatrice Bonanni
- Department of Physics, Università di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Roma, Italy
| | - Anna Sgarlata
- Department of Physics, Università di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Roma, Italy
| | - Massimo Fanfoni
- Department of Physics, Università di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Roma, Italy
| | - Roberto Martini
- Department of Chemical Science and Technologies, Università di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy
| | - Ilaria Di Filippo
- Department of Chemical Science and Technologies, Università di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy
| | - Gabriele Magna
- Department of Chemical Science and Technologies, Università di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy
| | - Manuela Stefanelli
- Department of Chemical Science and Technologies, Università di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy
| | - Donato Monti
- Department of Chemistry, Sapienza Università di Roma, Piazzale Aldo Moro 5, 00185 Rome, Italy
| | - Roberto Paolesse
- Department of Chemical Science and Technologies, Università di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy
| | - Claudio Goletti
- Department of Physics, Università di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Roma, Italy
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Wagner T, Antczak G, Ghanbari E, Navarro-Quezada A, Györök M, Volokitina A, Marschner F, Zeppenfeld P. Standard deviation of microscopy images used as indicator for growth stages. Ultramicroscopy 2022; 233:113427. [PMID: 34990906 DOI: 10.1016/j.ultramic.2021.113427] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 10/18/2021] [Accepted: 11/12/2021] [Indexed: 11/29/2022]
Abstract
Photoelectron emission microscopy (PEEM) and low energy electron microscopy (LEEM) can easily distinguish between organic molecules adsorbed in crystallites or in the wetting layers as well as the bare metal substrate due to their different electronic properties. Already before (and during) the condensation of such solid phases (2D islands or 3D crystallites), there is a dilute 2D gas phase. Such a 2D gas phase consists of molecules, which are highly mobile and diffuse across the surface. The individual molecules are too small to be resolved in PEEM/LEEM images. Here, we discuss, how image features below and above the resolution limit of a PEEM/LEEM affect the mean electron yield and its (normalized) standard deviation. We support our findings with two experimental examples: the deposition of cobalt phthalocyanine (CoPc) on Ag(100) and of perfluoro-pentacene on Ag(110). Our results demonstrate, how a spatial and temporal analysis of image series can be used to obtain information about molecular phases, which cannot be directly resolved in microscopy images.
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Affiliation(s)
- Thorsten Wagner
- Johannes Kepler University, Institute of Experimental Physics, Surface Science Division, Altenberger Str. 69, 4040 Linz, Austria.
| | - Grażyna Antczak
- University of Wrocław, Institute of Experimental Physics, Pl. M. Borna 9, 50-204 Wrocław, Poland.
| | - Ebrahim Ghanbari
- Johannes Kepler University, Institute of Experimental Physics, Surface Science Division, Altenberger Str. 69, 4040 Linz, Austria
| | - Andrea Navarro-Quezada
- Johannes Kepler University, Institute of Experimental Physics, Surface Science Division, Altenberger Str. 69, 4040 Linz, Austria; Johannes Kepler University, Institute of Semiconductor and Solid State Physics, Quantum Materials Group, Altenberger Str. 69, 4040 Linz, Austria.
| | - Michael Györök
- Johannes Kepler University, Institute of Experimental Physics, Surface Science Division, Altenberger Str. 69, 4040 Linz, Austria.
| | - Anna Volokitina
- Johannes Kepler University, Institute of Experimental Physics, Surface Science Division, Altenberger Str. 69, 4040 Linz, Austria
| | - Felix Marschner
- Johannes Kepler University, Institute of Experimental Physics, Surface Science Division, Altenberger Str. 69, 4040 Linz, Austria
| | - Peter Zeppenfeld
- Johannes Kepler University, Institute of Experimental Physics, Surface Science Division, Altenberger Str. 69, 4040 Linz, Austria.
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Calcinelli F, Jeindl A, Hörmann L, Ghan S, Oberhofer H, Hofmann OT. Interfacial Charge Transfer Influences Thin-Film Polymorphism. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2022; 126:2868-2876. [PMID: 35178141 PMCID: PMC8842301 DOI: 10.1021/acs.jpcc.1c09986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 01/12/2022] [Indexed: 05/05/2023]
Abstract
The structure and chemical composition are the key parameters influencing the properties of organic thin films deposited on inorganic substrates. Such films often display structures that substantially differ from the bulk, and the substrate has a relevant influence on their polymorphism. In this work, we illuminate the role of the substrate by studying its influence on para-benzoquinone on two different substrates, Ag(111) and graphene. We employ a combination of first-principles calculations and machine learning to identify the energetically most favorable structures on both substrates and study their electronic properties. Our results indicate that for the first layer, similar structures are favorable for both substrates. For the second layer, we find two significantly different structures. Interestingly, graphene favors the one with less, while Ag favors the one with more electronic coupling. We explain this switch in stability as an effect of the different charge transfer on the two substrates.
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Affiliation(s)
- Fabio Calcinelli
- Institute
of Solid State Physics, Graz University
of Technology, 8010 Graz, Austria
| | - Andreas Jeindl
- Institute
of Solid State Physics, Graz University
of Technology, 8010 Graz, Austria
| | - Lukas Hörmann
- Institute
of Solid State Physics, Graz University
of Technology, 8010 Graz, Austria
| | - Simiam Ghan
- Chair
for Theoretical Chemistry and Catalysis Research Center, Technical University Munich, 85748 Garching, Germany
| | - Harald Oberhofer
- Chair
for Theoretical Chemistry and Catalysis Research Center, Technical University Munich, 85748 Garching, Germany
- Chair
for Theoretical Physics VII and Bavarian Center for Battery Technology
(BayBatt), University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
| | - Oliver T. Hofmann
- Institute
of Solid State Physics, Graz University
of Technology, 8010 Graz, Austria
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Franco-Cañellas A, Duhm S, Gerlach A, Schreiber F. Binding and electronic level alignment of π-conjugated systems on metals. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2020; 83:066501. [PMID: 32101802 DOI: 10.1088/1361-6633/ab7a42] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
We review the binding and energy level alignment of π-conjugated systems on metals, a field which during the last two decades has seen tremendous progress both in terms of experimental characterization as well as in the depth of theoretical understanding. Precise measurements of vertical adsorption distances and the electronic structure together with ab initio calculations have shown that most of the molecular systems have to be considered as intermediate cases between weak physisorption and strong chemisorption. In this regime, the subtle interplay of different effects such as covalent bonding, charge transfer, electrostatic and van der Waals interactions yields a complex situation with different adsorption mechanisms. In order to establish a better understanding of the binding and the electronic level alignment of π-conjugated molecules on metals, we provide an up-to-date overview of the literature, explain the fundamental concepts as well as the experimental techniques and discuss typical case studies. Thereby, we relate the geometric with the electronic structure in a consistent picture and cover the entire range from weak to strong coupling.
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Affiliation(s)
- Antoni Franco-Cañellas
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
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