1
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Nowik-Boltyk EM, Junghoefer T, Giangrisostomi E, Ovsyannikov R, Shu C, Rajca A, Droghetti A, Casu MB. Radical-Induced Changes in Transition Metal Interfacial Magnetic Properties: A Blatter Derivative on Polycrystalline Cobalt. Angew Chem Int Ed Engl 2024:e202403495. [PMID: 38843268 DOI: 10.1002/anie.202403495] [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: 02/19/2024] [Indexed: 07/23/2024]
Abstract
In this work, we study the interface obtained by depositing a monolayer of a Blatter radical derivative on polycrystalline cobalt. By examining the occupied and unoccupied states at the interface, using soft X-ray techniques, combined with electronic structure calculations, we could simultaneously determine the electronic structure of both the molecular and ferromagnetic sides of the interface, thus obtaining a full understanding of the interfacial magnetic properties. We found that the molecule is strongly hybridized with the surface. Changes in the core level spectra reflect the modification of the molecule and the cobalt electronic structures inducing a decrease in the magnetic moment of the cobalt atoms bonded to the molecules which, in turn, lose their radical character. Our method allowed us to screen, beforehand, organic/ferromagnetic interfaces given their potential applications in spintronics.
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Affiliation(s)
| | - Tobias Junghoefer
- Institute of Physical and Theoretical Chemistry, University of Tübingen, 72076, Tübingen, Germany
| | - Erika Giangrisostomi
- Institute Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin, 12489, Berlin, Germany
| | - Ruslan Ovsyannikov
- Institute Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin, 12489, Berlin, Germany
| | - Chan Shu
- Department of Chemistry, University of Nebraska, Lincoln, NE 68588, United States
| | - Andrzej Rajca
- Department of Chemistry, University of Nebraska, Lincoln, NE 68588, United States
| | - Andrea Droghetti
- School of Physics and CRANN, Trinity College, the University of Dublin, Dublin, D02, Ireland
| | - M Benedetta Casu
- Institute of Physical and Theoretical Chemistry, University of Tübingen, 72076, Tübingen, Germany
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2
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Klein BP, Stoodley MA, Morgan DB, Rochford LA, Williams LBS, Ryan PTP, Sattler L, Weber SM, Hilt G, Liddy TJ, Lee TL, Maurer RJ, Duncan DA. Probing the role of surface termination in the adsorption of azupyrene on copper. NANOSCALE 2024. [PMID: 38426652 DOI: 10.1039/d3nr04690g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
The role of the inorganic substrate termination, within the organic-inorganic interface, has been well studied for systems that contain strong localised bonding. However, how varying the substrate termination affects coordination to delocalised electronic states, like that found in aromatic molecules, is an open question. Azupyrene, a non-alternant polycyclic aromatic hydrocarbon, is known to bind strongly to metal surfaces through its delocalised π orbitals, thus yielding an ideal probe into delocalised surface-adsorbate interactions. Normal incidence X-ray standing wave (NIXSW) measurements and density functional theory calculations are reported for the adsorption of azupyrene on the (111), (110) and (100) surface facets of copper to investigate the dependence of the adsorption structure on the substrate termination. Structural models based on hybrid density functional theory calculations with non-local many-body dispersion yield excellent agreement with the experimental NIXSW results. No statistically significant difference in the azupyrene adsorption height was observed between the (111) and (100) surfaces. On the Cu(110) surface, the molecule was found to adsorb 0.06 ± 0.04 Å closer to the substrate than on the other surface facets. The most energetically favoured adsorption site on each surface, as determined by DFT, is subtly different, but in each case involved a configuration where the aromatic rings were centred above a hollow site, consistent with previous reports for the adsorption of small aromatic molecules on metal surfaces.
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Affiliation(s)
- Benedikt P Klein
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK.
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK.
| | - Matthew A Stoodley
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK.
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK.
| | - Dylan B Morgan
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK.
| | - Luke A Rochford
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK.
| | - Leon B S Williams
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK.
- School of Chemistry, University of Glasgow, University Avenue, Glasgow, G12 8QQ, UK
- School of Physics and Astronomy, University of Glasgow, University Avenue, Glasgow, G12 8QQ, UK
| | - Paul T P Ryan
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK.
- Department of Materials, Imperial College London, Prince Consort Rd, SW7 2AZ, UK
| | - Lars Sattler
- Institut für Chemie, Carl von Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26111 Oldenburg, Germany
| | - Sebastian M Weber
- Institut für Chemie, Carl von Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26111 Oldenburg, Germany
| | - Gerhard Hilt
- Institut für Chemie, Carl von Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26111 Oldenburg, Germany
| | - Thomas J Liddy
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK.
- School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Tien-Lin Lee
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK.
| | - Reinhard J Maurer
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK.
- Department of Physics, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK
| | - David A Duncan
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK.
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3
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Brill L, Brandhoff J, Gruenewald M, Calcinelli F, Hofmann OT, Forker R, Fritz T. Partial restoration of aromaticity of pentacene-5,7,12,14-tetrone on Cu(111). NANOSCALE 2024; 16:2654-2661. [PMID: 38230573 PMCID: PMC10832359 DOI: 10.1039/d3nr04848a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 01/04/2024] [Indexed: 01/18/2024]
Abstract
The π-conjugation of organic molecules can be strongly influenced when functional groups are added to a molecule, for example when pentacene is converted into pentacene-5,7,12,14-tetrone (P4O) by substitution of four H-atoms with four O-atoms, leading to four CO double bonds. In fact, although free P4O resembles the parent hydrocarbon pentacene structurally at a first glance, its electronic properties differ drastically and can be more accurately described by three benzene units connected via four carbonyl groups. If P4O is deposited onto Cu(111), the electronic interaction across the interface has previously been reported to fully restore the π-conjugation through a weakening of the CO double bonds and a redistribution of electrons, both of which have been explained with the model of surface-induced aromatic stabilization. Here, we observe for the case of P4O on Cu(111) that the molecule does not exhibit full π-conjugation upon interaction with the surface, likely because of the special electronic nature of the hybridized P4O on Cu(111). Our results are derived from CO-functionalized noncontact atomic force microscopy measurements in combination with dispersion-corrected density functional theory calculations yielding bond lengths and molecular geometries. To characterize the aromaticity, we apply the harmonic oscillator model of aromaticity.
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Affiliation(s)
- Lorenz Brill
- Friedrich Schiller University Jena, Institute of Solid State Physics, Helmholtzweg 5, 07743 Jena, Germany.
| | - Jonas Brandhoff
- Friedrich Schiller University Jena, Institute of Solid State Physics, Helmholtzweg 5, 07743 Jena, Germany.
| | - Marco Gruenewald
- Friedrich Schiller University Jena, Institute of Solid State Physics, Helmholtzweg 5, 07743 Jena, Germany.
| | - Fabio Calcinelli
- Graz University of Technology, Institute of Solid State Physics, NAWI Graz, Petersgasse 16/II, 8010 Graz, Austria.
| | - Oliver T Hofmann
- Graz University of Technology, Institute of Solid State Physics, NAWI Graz, Petersgasse 16/II, 8010 Graz, Austria.
| | - Roman Forker
- Friedrich Schiller University Jena, Institute of Solid State Physics, Helmholtzweg 5, 07743 Jena, Germany.
| | - Torsten Fritz
- Friedrich Schiller University Jena, Institute of Solid State Physics, Helmholtzweg 5, 07743 Jena, Germany.
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4
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Zhou G, Li P, Xiao Y, Chen S, Weng S, Dong R, Lin D, Wu DY, Yang L. Observing π-Au Interaction between Aromatic Molecules and Single Au Nanodimers with a Subnanometer Gap by SERS. Anal Chem 2024; 96:197-203. [PMID: 38016046 DOI: 10.1021/acs.analchem.3c03600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2023]
Abstract
Interface interaction between aromatic molecules and noble metals plays a prominent role in fundamental science and technological applications. However, probing π-metal interactions under ambient conditions remains challenging, as it requires characterization techniques to have high sensitivity and molecular specificity without any restrictions on the sample. Herein, the interactions between polycyclic aromatic hydrocarbon (PAH) molecules and Au nanodimers with a subnanometer gap are investigated by surface-enhanced Raman spectroscopy (SERS). A cleaner and stronger plasmonic field of subnanometer gap Au nanodimer structures was constructed through solvent extraction. High sensitivity and strong π-Au interaction between PAHs and Au nanodimers are observed. Additionally, the density functional theory calculation confirmed the interactions of PAHs physically absorbed on the Au surface; the binding energy and differential charge further theoretically indicated the correlation between the sensitivity and the number of PAH rings, which is consistent with SERS experimental results. This work provides a new method to understand the interactions between aromatic molecules and noble metal surfaces in an ambient environment, also paving the way for designing the interfaces in the fields of catalysis, sensors, and molecular electronics.
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Affiliation(s)
- Guoliang Zhou
- Institute of Health and Medical Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
- University of Science & Technology of China, Hefei 230026, Anhui China
| | - Pan Li
- Institute of Health and Medical Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
- Department of Pharmacy, Hefei Cancer Hospital, Chinese Academy of Sciences, Hefei 230031, Anhui China
| | - Yuanhui Xiao
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Siyu Chen
- Institute of Health and Medical Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
- University of Science & Technology of China, Hefei 230026, Anhui China
| | - Shirui Weng
- Institute of Health and Medical Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
| | - Ronglu Dong
- Institute of Health and Medical Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
| | - Dongyue Lin
- Institute of Health and Medical Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
- Department of Pharmacy, Hefei Cancer Hospital, Chinese Academy of Sciences, Hefei 230031, Anhui China
| | - De-Yin Wu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Liangbao Yang
- Institute of Health and Medical Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
- University of Science & Technology of China, Hefei 230026, Anhui China
- Department of Pharmacy, Hefei Cancer Hospital, Chinese Academy of Sciences, Hefei 230031, Anhui China
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5
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Niederreiter M, Cartus J, Werkovits A, Hofmann OT, Risse T, Sterrer M. Interplay of Adsorption Geometry and Work Function Evolution at the TCNE/Cu(111) Interface. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2023; 127:24266-24273. [PMID: 38148848 PMCID: PMC10749461 DOI: 10.1021/acs.jpcc.3c06422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 11/21/2023] [Accepted: 11/22/2023] [Indexed: 12/28/2023]
Abstract
The adsorption of organic electron acceptors on metal surfaces is a powerful way to change the effective work function of the substrate through the formation of charge-transfer-induced dipoles. The work function of the interfaces is hence controlled by the redistribution of charges upon adsorption of the organic layer, which depends not only on the electron affinity of the organic material but also on the adsorption geometry. As shown in this work, the latter dependence controls the work function also in the case of adsorbate layers exhibiting a mixture of various adsorption geometries. Based on a combined experimental (core-level and infrared spectroscopy) and theoretical (density functional theory) study for tetracyanoethylene (TCNE) on Cu(111), we find that TCNE adsorbs in at least three different orientations, depending on TCNE coverage. At low coverage, flat lying TCNE dominates, as it possesses the highest adsorption energy. At a higher coverage, additionally, two different standing orientations are found. This is accompanied by a large increase in the work function of almost 3 eV at full monolayer coverage. Our results suggest that the large increase in work function is mainly due to the surface dipole of the free CN groups of the standing molecules and less dependent on the charge-transfer dipole of the differently oriented and charged molecules. This, in turn, opens new opportunities to control the work function of interfaces, e.g., by synthetic modification of the adsorbates, which may allow one to alter the adsorption geometries of the molecules as well as their contributions to the interface dipoles and, hence, the work function.
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Affiliation(s)
- Max Niederreiter
- Institute
of Physics, University of Graz, NAWI Graz, Universitätsplatz
5, 8010 Graz, Austria
| | - Johannes Cartus
- Institute
of Solid State Physics, Graz University
of Technology, NAWI Graz, Petersgasse, 16/II, 8010 Graz, Austria
| | - Anna Werkovits
- Institute
of Solid State Physics, Graz University
of Technology, NAWI Graz, Petersgasse, 16/II, 8010 Graz, Austria
| | - Oliver T. Hofmann
- Institute
of Solid State Physics, Graz University
of Technology, NAWI Graz, Petersgasse, 16/II, 8010 Graz, Austria
| | - Thomas Risse
- Institute
of Chemistry and Biochemistry, Freie Universität
Berlin, Arminallee 22, 14195 Berlin, Germany
| | - Martin Sterrer
- Institute
of Physics, University of Graz, NAWI Graz, Universitätsplatz
5, 8010 Graz, Austria
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6
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Xi J, Xue R, Li X, Lin Y, Peng G, Wang J, You S, Xu C, Zhang H, Chi L. Highly Selective On-Surface [2 + 2] Cycloaddition Induced by Hierarchical Metal-Organic Hybrids. J Phys Chem Lett 2023; 14:1585-1591. [PMID: 36748856 DOI: 10.1021/acs.jpclett.2c03913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
On-surface synthesis of phenylenes is a promising strategy to form extended π-conjugated frameworks but normally lacks selectivity in achieving uniform products. Herein we demonstrate that the debromination reaction of 2,3-dibromophenazine (DBPZ) on Au(111) and Ag(111) surfaces can vary significantly considering the involvement of metal-organic hybrids (MOHs). On Au(111), [2 + 2] and [2 + 2 + 2] cycloadditions facilitate instantaneously upon the debromination occurring, while on Ag(111), several MOHs have been observed under sequential thermal annealing, leading to finally the uniform [2 + 2] cycloaddition product exclusively. By means of scanning tunneling microscopy (STM) and bond-resolved atomic force microscopy (BR-AFM), we have unambiguously depicted the chemical structure of related reaction intermediates and unraveled the undocumented role of hierarchical evolution of MOHs in steering the chemical selectivity.
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Affiliation(s)
- Jiahao Xi
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou 215123, Jiangsu, P. R. China
| | - Renjie Xue
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou 215123, Jiangsu, P. R. China
| | - Xuechao Li
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou 215123, Jiangsu, P. R. China
| | - Yu Lin
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou 215123, Jiangsu, P. R. China
| | - Guyue Peng
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou 215123, Jiangsu, P. R. China
| | - Junbo Wang
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou 215123, Jiangsu, P. R. China
| | - Sifan You
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou 215123, Jiangsu, P. R. China
| | - Chaojie Xu
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou 215123, Jiangsu, P. R. China
| | - Haiming Zhang
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou 215123, Jiangsu, P. R. China
| | - Lifeng Chi
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou 215123, Jiangsu, P. R. China
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7
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Chen Y, Jones LO, Lee TL, Das A, Mosquera MA, Keane DT, Schatz GC, Bedzyk MJ. Atomic-Site-Specific Surface Valence-Band Structure from X-Ray Standing-Wave Excited Photoemission. PHYSICAL REVIEW LETTERS 2022; 128:206801. [PMID: 35657902 DOI: 10.1103/physrevlett.128.206801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 04/06/2022] [Indexed: 06/15/2023]
Abstract
X-ray standing-wave (XSW) excited photoelectron emission was used to measure the site-specific valence band (VB) for ½ monolayer (ML) Pt grown on a SrTiO_{3} (001) surface. The XSW induced modulations in the core level (CL), and VB photoemission from the surface and substrate atoms were monitored for three hkl substrate Bragg reflections. The XSW CL analysis shows the Pt to have a face-centered-cubic-like cube-on-cube epitaxy with the substrate. The XSW VB information compares well to a density functional theory calculated projected density of states from the surface and substrate atoms. Overall, this Letter represents a novel method for determining the contribution to the density of states by valence electrons from specific atomic surface sites.
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Affiliation(s)
- Yanna Chen
- Department of Materials Science and Engineering, Northwestern University, Illinois 60208, USA
| | - Leighton O Jones
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA
| | - Tien Lin Lee
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
| | - Anusheela Das
- Department of Materials Science and Engineering, Northwestern University, Illinois 60208, USA
| | - Martín A Mosquera
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, USA
| | - Denis T Keane
- Department of Materials Science and Engineering, Northwestern University, Illinois 60208, USA
| | - George C Schatz
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA
| | - Michael J Bedzyk
- Department of Materials Science and Engineering, Northwestern University, Illinois 60208, USA
- Department of Physics and Astronomy, Northwestern University, Illinois 60208, USA
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8
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Berger R, Jeindl A, Hörmann L, Hofmann OT. Role of Adatoms for the Adsorption of F4TCNQ on Au(111). THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2022; 126:7718-7727. [PMID: 35558824 PMCID: PMC9082607 DOI: 10.1021/acs.jpcc.2c00994] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 03/25/2022] [Indexed: 06/15/2023]
Abstract
Organic adlayers on inorganic substrates often contain adatoms, which can be incorporated within the adsorbed molecular species, forming two-dimensional metal-organic frameworks at the substrate surface. The interplay between native adatoms and adsorbed molecules significantly changes various adlayer properties such as the adsorption geometry, the bond strength between the substrate and the adsorbed species, or the work function at the interface. Here, we use dispersion-corrected density functional theory to gain insight into the energetics that drive the incorporation of native adatoms within molecular adlayers based on the prototypical, experimentally well-characterized system of F4TCNQ on Au(111). We explain the adatom-induced modifications in the adsorption geometry and the adsorption energy based on the electronic structure and charge transfer at the interface.
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9
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Tetrathiafulvalenes as anchors for building highly conductive and mechanically tunable molecular junctions. Nat Commun 2022; 13:1803. [PMID: 35379823 PMCID: PMC8980061 DOI: 10.1038/s41467-022-29483-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 03/02/2022] [Indexed: 11/08/2022] Open
Abstract
AbstractThe interface between molecules and electrodes has great impact on charge transport of molecular devices. Precisely manipulating the structure and electronic coupling of electrode-molecule interface at a molecular level is very challenging. Here, we develop new molecular junctions based on tetrathiafulvalene (TTF)-fused naphthalene diimide (NDI) molecules which are anchored to gold electrodes through direct TTF-Au contacts formed via Au-S bonding. These contacts enable highly efficient orbital hybridization of gold electrodes and the conducting π-channels, yielding strong electrode-molecule coupling and remarkably high conductivity in the junctions. By further introducing additional thiohexyl (SHe) anchors to the TTF units, we develop molecular wires with multiple binding sites and demonstrate reversibly switchable electrode-molecule contacts and junction conductance through mechanical control. These findings show a superb electrode-molecule interface and provide a new strategy for precisely tunning the conductance of molecular devices towards new functions.
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10
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Borchert JW, Weitz RT, Ludwigs S, Klauk H. A Critical Outlook for the Pursuit of Lower Contact Resistance in Organic Transistors. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2104075. [PMID: 34623710 DOI: 10.1002/adma.202104075] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 08/20/2021] [Indexed: 06/13/2023]
Abstract
To take full advantage of recent and anticipated improvements in the performance of organic semiconductors employed in organic transistors, the high contact resistance arising at the interfaces between the organic semiconductor and the source and drain contacts must be reduced significantly. To date, only a small portion of the accumulated research on organic thin-film transistors (TFTs) has reported channel-width-normalized contact resistances below 100 Ωcm, well above what is regularly demonstrated in transistors based on inorganic semiconductors. A closer look at these cases and the relevant literature strongly suggests that the most significant factor leading to the lowest contact resistances in organic TFTs so far has been the control of the thin-film morphology of the organic semiconductor. By contrast, approaches aimed at increasing the charge-carrier density and/or reducing the intrinsic Schottky barrier height have so far played a relatively minor role in achieving the lowest contact resistances. Herein, the possible explanations for these observations are explored, including the prevalence of Fermi-level pinning and the difficulties in forming optimized interfaces with organic semiconductors. An overview of the research on these topics is provided, and potential device-engineering solutions are discussed based on recent advancements in the theoretical and experimental work on both organic and inorganic semiconductors.
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Affiliation(s)
- James W Borchert
- 1st Institute of Physics, Georg August University of Göttingen, Friedrich-Hund-Platz 1, 37077, Göttingen, Germany
| | - R Thomas Weitz
- 1st Institute of Physics, Georg August University of Göttingen, Friedrich-Hund-Platz 1, 37077, Göttingen, Germany
| | - Sabine Ludwigs
- IPOC - Functional Polymers, Institute of Polymer Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Hagen Klauk
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569, Stuttgart, Germany
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11
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Duncan DA, Blowey PJ, Lee TL, Allegretti F, Nielsen CB, Rochford LA. Quantitative Insights into the Adsorption Structure of Diindeno[1,2- a;1',2'- c]fluorene-5,10,15-trione (Truxenone) on a Cu(111) Surface Using X-ray Standing Waves. ACS OMEGA 2021; 6:34525-34531. [PMID: 34963937 PMCID: PMC8697368 DOI: 10.1021/acsomega.1c04799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 11/25/2021] [Indexed: 06/14/2023]
Abstract
The adsorption structure of truxenone on Cu(111) was determined quantitatively using normal-incidence X-ray standing waves. The truxenone molecule was found to chemisorb on the surface, with all adsorption heights of the dominant species on the surface less than ∼2.5 Å. The phenyl backbone of the molecule adsorbs mostly parallel to the underlying surface, with an adsorption height of 2.32 ± 0.08 Å. The C atoms bound to the carbonyl groups are located closer to the surface at 2.15 ± 0.10 Å, a similar adsorption height to that of the chemisorbed O species; however, these O species were found to adsorb at two different adsorption heights, 1.96 ± 0.08 and 2.15 ± 0.06 Å, at a ratio of 1:2, suggesting that on average, one O atom per adsorbed truxenone molecule interacts more strongly with the surface. The adsorption geometry determined herein is an important benchmark for future theoretical calculations concerning both the interaction with solid surfaces and the electronic properties of a molecule with electron-accepting properties for applications in organic electronic devices.
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Affiliation(s)
- David A. Duncan
- Diamond
Light Source, Harwell Science and Innovation
Campus, Didcot OX11 0DE, U.K.
| | - Philip J. Blowey
- Diamond
Light Source, Harwell Science and Innovation
Campus, Didcot OX11 0DE, U.K.
- Physics
Department, University of Warwick, Coventry CV4 7AL, U.K.
| | - Tien-Lin Lee
- Diamond
Light Source, Harwell Science and Innovation
Campus, Didcot OX11 0DE, U.K.
| | - Francesco Allegretti
- Physics
Department E20, Technical University of
Munich, James Franck
Straße 1, D-85748 Garching, Germany
| | - Christian B. Nielsen
- Department
of Chemistry, Queen Mary University of London, Mile End Road, London E1 4NS, U.K.
| | - Luke A. Rochford
- Diamond
Light Source, Harwell Science and Innovation
Campus, Didcot OX11 0DE, U.K.
- Chemistry
Department, University of Warwick, Coventry CV4 7AL, U.K.
- Chemistry
Department, University of Birmingham, University Road, Birmingham B15 2TT, U.K.
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12
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Cartus J, Jeindl A, Hofmann OT. Can We Predict Interface Dipoles Based on Molecular Properties? ACS OMEGA 2021; 6:32270-32276. [PMID: 34870047 PMCID: PMC8638305 DOI: 10.1021/acsomega.1c05092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 11/02/2021] [Indexed: 05/12/2023]
Abstract
We apply high-throughput density functional theory calculations and symbolic regression to hybrid inorganic/organic interfaces with the intent to extract physically meaningful correlations between the adsorption-induced work function modifications and the properties of the constituents. We separately investigate two cases: (1) hypothetical, free-standing self-assembled monolayers with a large intrinsic dipole moment and (2) metal-organic interfaces with a large charge-transfer-induced dipole. For the former, we find, without notable prior assumptions, the Topping model, as expected from the literature. For the latter, highly accurate correlations are found, which are, however, clearly unphysical.
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13
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Liu L, Timmer A, Kolodzeiski E, Gao HY, Mönig H, Klaasen H, Meng X, Ren J, Studer A, Amirjalayer S, Fuchs H. Conformational evolution following the sequential molecular dehydrogenation of PMDI on a Cu(111) surface. NANOSCALE ADVANCES 2021; 3:6373-6378. [PMID: 36133488 PMCID: PMC9417866 DOI: 10.1039/d1na00590a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 10/06/2021] [Indexed: 06/15/2023]
Abstract
Molecular spatial conformational evolution following the corresponding chemical reaction pathway at surfaces is important to understand and optimize chemical processes. Combining experimental and theoretical methods, the sequential N-H and C-H dehydrogenation of pyromellitic diimide (PMDI) on a Cu(111) surface are reported. STM experiments and atomistic modeling allow structural analysis at each well-defined reaction step. First, exclusively the aromatic N-H dehydrogenation of the imide group is observed. Subsequently, the C-H group at the benzene core of PMDI gets activated leading to a dehydrogenation reaction forming metalorganic species where Cu adatoms pronouncedly protruding from the surface are coordinated by one or two PMDI ligands at the surface. All reactions of PMDI induce conformational changes at the surface as confirmed by STM imaging and DFT simulations. Such conformational evolution in sequential N-H and C-H activation provides a detailed insight to understand molecular dehydrogenation processes at surfaces.
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Affiliation(s)
- Lacheng Liu
- Physikalisches Institut, Westfälische Wilhelms-Universität Wilhelm-Klemm-Straße 10 48149 Münster Germany
- Center for Nanotechnology (CeNTech) Heisenbergstraße 11 48149 Münster Germany
| | - Alexander Timmer
- Physikalisches Institut, Westfälische Wilhelms-Universität Wilhelm-Klemm-Straße 10 48149 Münster Germany
- Center for Nanotechnology (CeNTech) Heisenbergstraße 11 48149 Münster Germany
| | - Elena Kolodzeiski
- Physikalisches Institut, Westfälische Wilhelms-Universität Wilhelm-Klemm-Straße 10 48149 Münster Germany
- Center for Nanotechnology (CeNTech) Heisenbergstraße 11 48149 Münster Germany
| | - Hong-Ying Gao
- Physikalisches Institut, Westfälische Wilhelms-Universität Wilhelm-Klemm-Straße 10 48149 Münster Germany
- Center for Nanotechnology (CeNTech) Heisenbergstraße 11 48149 Münster Germany
- School of Chemical Engineering and Technology, Tianjin University 300072 Tianjin China
| | - Harry Mönig
- Physikalisches Institut, Westfälische Wilhelms-Universität Wilhelm-Klemm-Straße 10 48149 Münster Germany
- Center for Nanotechnology (CeNTech) Heisenbergstraße 11 48149 Münster Germany
| | - Henning Klaasen
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster Corrensstraße 40 48149 Münster Germany
| | - Xiangzhi Meng
- Physikalisches Institut, Westfälische Wilhelms-Universität Wilhelm-Klemm-Straße 10 48149 Münster Germany
- Center for Nanotechnology (CeNTech) Heisenbergstraße 11 48149 Münster Germany
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel Leibnizstraße 19 24118 Kiel Germany
| | - Jindong Ren
- Physikalisches Institut, Westfälische Wilhelms-Universität Wilhelm-Klemm-Straße 10 48149 Münster Germany
- Center for Nanotechnology (CeNTech) Heisenbergstraße 11 48149 Münster Germany
- CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology Beijing 100190 P. R. China
| | - Armido Studer
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster Corrensstraße 40 48149 Münster Germany
| | - Saeed Amirjalayer
- Physikalisches Institut, Westfälische Wilhelms-Universität Wilhelm-Klemm-Straße 10 48149 Münster Germany
- Center for Nanotechnology (CeNTech) Heisenbergstraße 11 48149 Münster Germany
| | - Harald Fuchs
- Physikalisches Institut, Westfälische Wilhelms-Universität Wilhelm-Klemm-Straße 10 48149 Münster Germany
- Center for Nanotechnology (CeNTech) Heisenbergstraße 11 48149 Münster Germany
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14
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Kwon S, Jeong DY, Chae WS, Noh K, Devi P, Colazzo L, You Y, Choi T, Kim DW. Electronic structures and optical characteristics of fluorescent pyrazinoquinoxaline assemblies and Au interfaces. Sci Rep 2021; 11:16978. [PMID: 34417488 PMCID: PMC8379188 DOI: 10.1038/s41598-021-96437-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 08/10/2021] [Indexed: 11/09/2022] Open
Abstract
Understanding the excitonic processes at the interfaces of fluorescent π-conjugated molecules and metal electrodes is important for both fundamental studies and emerging applications. Adsorption configurations of molecules on metal surfaces significantly affect the physical characteristics of junctions as well as molecules. Here, the electronic structures and optical properties of molecular assemblies/Au interfaces were investigated using scanning probe and photoluminescence microscopy techniques. Scanning tunneling microscopy images and tunneling conductance spectra suggested that the self-assembled molecules were physisorbed on the Au surface. Visible-range photoluminescence studies showed that Au thin films modified the emission spectra and reduced the lifetime of excitons. Surface potential maps, obtained by Kelvin probe force microscopy, could visualize electron transfer from the molecules to Au under illumination, which could explain the decreased lifetime of excitons at the molecule/Au interface.
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Affiliation(s)
- Soyeong Kwon
- Department of Physics, Ewha Womans University, Seoul, 03760, South Korea
| | - Dong Yeun Jeong
- Division of Chemical Engineering and Materials Science, and Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul, 03760, South Korea
| | - Weon-Sik Chae
- Daegu Center, Korea Basic Science Institute (KBSI), Daegu, 41566, South Korea
| | - Kyungju Noh
- Department of Physics, Ewha Womans University, Seoul, 03760, South Korea.,Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul, 03760, South Korea
| | - P Devi
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul, 03760, South Korea.,Ewha Womans University, Seoul, 03760, South Korea
| | - Luciano Colazzo
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul, 03760, South Korea.,Ewha Womans University, Seoul, 03760, South Korea
| | - Youngmin You
- Division of Chemical Engineering and Materials Science, and Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul, 03760, South Korea.
| | - Taeyoung Choi
- Department of Physics, Ewha Womans University, Seoul, 03760, South Korea.
| | - Dong-Wook Kim
- Department of Physics, Ewha Womans University, Seoul, 03760, South Korea.
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15
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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: 0] [Impact Index Per Article: 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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16
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Wang Q, Yang J, Franco-Cañellas A, Bürker C, Niederhausen J, Dombrowski P, Widdascheck F, Breuer T, Witte G, Gerlach A, Duhm S, Schreiber F. Pentacene/perfluoropentacene bilayers on Au(111) and Cu(111): impact of organic-metal coupling strength on molecular structure formation. NANOSCALE ADVANCES 2021; 3:2598-2606. [PMID: 36134152 PMCID: PMC9419101 DOI: 10.1039/d1na00040c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Accepted: 03/08/2021] [Indexed: 05/12/2023]
Abstract
As crucial element in organic opto-electronic devices, heterostructures are of pivotal importance. In this context, a comprehensive study of the properties on a simplified model system of a donor-acceptor (D-A) bilayer structure is presented, using ultraviolet photoelectron spectroscopy (UPS), X-ray photoelectron spectroscopy (XPS), low-energy electron diffraction (LEED) and normal-incidence X-ray standing wave (NIXSW) measurements. Pentacene (PEN) as donor and perfluoropentacene (PFP) as acceptor material are chosen to produce bilayer structures on Au(111) and Cu(111) by sequential monolayer deposition of the two materials. By comparing the adsorption behavior of PEN/PFP bilayers on such weakly and strongly interacting substrates, it is found that: (i) the adsorption distance of the first layer (PEN or PFP) indicates physisorption on Au(111), (ii) the characteristics of the bilayer structure on Au(111) are (almost) independent of the deposition sequence, and hence, (iii) in both cases a mixed bilayer is formed on the Au substrate. This is in striking contrast to PFP/PEN bilayers on Cu(111), where strong chemisorption pins PEN molecules to the metal surface and no intermixing is induced by subsequent PFP deposition. The results illustrate the strong tendency of PEN and PFP molecules to mix, which has important implications for the fabrication of PEN/PFP heterojunctions.
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Affiliation(s)
- Qi Wang
- Institut für Angewandte Physik, Universität Tübingen 72076 Tübingen Germany
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices and Joint International Research Laboratory of Carbon-Based Functional Materials and Devices, Soochow University Suzhou 215123 People's Republic of China
| | - Jiacheng Yang
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices and Joint International Research Laboratory of Carbon-Based Functional Materials and Devices, Soochow University Suzhou 215123 People's Republic of China
| | | | - Christoph Bürker
- Institut für Angewandte Physik, Universität Tübingen 72076 Tübingen Germany
| | - Jens Niederhausen
- Helmholtz Zentrum Berlin für Materialien und Energie GmbH 14109 Berlin Germany
| | - Pierre Dombrowski
- Fachbereich Physik, Philipps-Universität Marburg 35032 Marburg Germany
| | - Felix Widdascheck
- Fachbereich Physik, Philipps-Universität Marburg 35032 Marburg Germany
| | - Tobias Breuer
- Fachbereich Physik, Philipps-Universität Marburg 35032 Marburg Germany
| | - Gregor Witte
- Fachbereich Physik, Philipps-Universität Marburg 35032 Marburg Germany
| | - Alexander Gerlach
- Institut für Angewandte Physik, Universität Tübingen 72076 Tübingen Germany
| | - Steffen Duhm
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices and Joint International Research Laboratory of Carbon-Based Functional Materials and Devices, Soochow University Suzhou 215123 People's Republic of China
| | - Frank Schreiber
- Institut für Angewandte Physik, Universität Tübingen 72076 Tübingen Germany
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17
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Jeindl A, Domke J, Hörmann L, Sojka F, Forker R, Fritz T, Hofmann OT. Nonintuitive Surface Self-Assembly of Functionalized Molecules on Ag(111). ACS NANO 2021; 15:6723-6734. [PMID: 33728893 PMCID: PMC8155339 DOI: 10.1021/acsnano.0c10065] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 03/10/2021] [Indexed: 05/22/2023]
Abstract
The fabrication of nanomaterials involves self-ordering processes of functional molecules on inorganic surfaces. To obtain specific molecular arrangements, a common strategy is to equip molecules with functional groups. However, focusing on the functional groups alone does not provide a comprehensive picture. Especially at interfaces, processes that govern self-ordering are complex and involve various physical and chemical effects, often leading to unexpected structures, as we showcase here on the example of a homologous series of quinones on Ag(111). Naively, one could expect that such quinones, which all bear the same functionalization, form similar motifs. In salient contrast, our joint theoretical and experimental study shows that profoundly different structures are formed. Using a machine-learning-based structure search algorithm, we find that this is due to a shift of the balance of three antagonizing driving forces: adsorbate-substrate interactions governing adsorption sites, adsorbate-adsorbate interactions favoring close packing, and steric hindrance inhibiting certain otherwise energetically beneficial molecular arrangements. The theoretical structures show excellent agreement with our experimental characterizations of the organic/inorganic interfaces, both for the unit cell sizes and the orientations of the molecules within. The nonintuitive interplay of similarly important interaction mechanisms will continue to be a challenging aspect for the design of functional interfaces. With a detailed examination of all driving forces, we are, however, still able to devise a design principle for self-assembly of functionalized molecules.
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Affiliation(s)
- Andreas Jeindl
- Institute
of Solid State Physics, NAWI Graz, Graz
University of Technology, Petersgasse 16, 8010 Graz, Austria
| | - Jari Domke
- Institute
for Solid State Physics, Friedrich Schiller
University Jena, Helmholtzweg 5, 07743 Jena, Germany
| | - Lukas Hörmann
- Institute
of Solid State Physics, NAWI Graz, Graz
University of Technology, Petersgasse 16, 8010 Graz, Austria
| | - Falko Sojka
- Institute
for Solid State Physics, Friedrich Schiller
University Jena, Helmholtzweg 5, 07743 Jena, Germany
| | - Roman Forker
- Institute
for Solid State Physics, Friedrich Schiller
University Jena, Helmholtzweg 5, 07743 Jena, Germany
| | - Torsten Fritz
- Institute
for Solid State Physics, Friedrich Schiller
University Jena, Helmholtzweg 5, 07743 Jena, Germany
| | - Oliver T. Hofmann
- Institute
of Solid State Physics, NAWI Graz, Graz
University of Technology, Petersgasse 16, 8010 Graz, Austria
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18
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Gupta NK, Schultz T, Karuppannan SK, Vilan A, Koch N, Nijhuis CA. The energy level alignment of the ferrocene-EGaIn interface studied with photoelectron spectroscopy. Phys Chem Chem Phys 2021; 23:13458-13467. [PMID: 34095913 DOI: 10.1039/d1cp01690c] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The energy level alignment after the formation of a molecular tunnel junction is often poorly understood because spectroscopy inside junctions is not possible, which hampers the rational design of functional molecular junctions and complicates the interpretation of the data generated by molecular junctions. In molecular junction platforms where the top electrode-molecule interaction is weak; one may argue that the energy level alignment can be deduced from measurements with the molecules supported by the bottom electrode (sometimes referred to as "half junctions"). This approach, however, still relies on a series of assumptions, which are challenging to address experimentally due to difficulties in studying the molecule-top electrode interaction. Herein, we describe top electrode-molecule junctions with a liquid metal alloy top electrode of EGaIn (which stands for eutectic alloy of Ga and In) interacting with well-characterised ferrocene (Fc) moieties. We deposited a ferrocene derivative on films of EGaIn, coated with its native GaOx layer, and studied the energy level alignment with photoelectron spectroscopy. Our results reveal that the electronic interaction between the Fc and GaOx/EGaIn is very weak, resembling physisorption. Therefore, investigations of "half junctions" for this system can provide valuable information regarding the energy level alignment of complete EGaIn junctions. Our results help to improve our understanding of the energy landscape in weakly coupled molecular junctions and aid to the rational design of molecular electronic devices.
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Affiliation(s)
- Nipun Kumar Gupta
- Departement of Chemistry, Faculty of Science, National University of Singapore, Singapore, Singapore and Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, Singapore 117546, Singapore
| | - Thorsten Schultz
- Institut für Physik, Humboldt-Universität zu Berlin, Newtonstraße 15, 12489 Berlin, Germany. and Helmholtz Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein Straße 15, 12489 Berlin, Germany
| | - Senthil Kumar Karuppannan
- Departement of Chemistry, Faculty of Science, National University of Singapore, Singapore, Singapore
| | - Ayelet Vilan
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Norbert Koch
- Institut für Physik, Humboldt-Universität zu Berlin, Newtonstraße 15, 12489 Berlin, Germany. and Helmholtz Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein Straße 15, 12489 Berlin, Germany
| | - Christian A Nijhuis
- Departement of Chemistry, Faculty of Science, National University of Singapore, Singapore, Singapore and Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, Singapore 117546, Singapore and Department of Molecules and Materials, MESA+ Institute for Nanotechnology and Center for Brain-Inspired Nano Systems, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
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19
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Gómez-Herrero AC, Sánchez-Sánchez C, Chérioux F, Martínez JI, Abad J, Floreano L, Verdini A, Cossaro A, Mazaleyrat E, Guisset V, David P, Lisi S, Martín Gago JA, Coraux J. Copper-assisted oxidation of catechols into quinone derivatives. Chem Sci 2020; 12:2257-2267. [PMID: 34163992 PMCID: PMC8179264 DOI: 10.1039/d0sc04883f] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Catechols are ubiquitous substances often acting as antioxidants, thus of importance in a variety of biological processes. The Fenton and Haber–Weiss processes are thought to transform these molecules into aggressive reactive oxygen species (ROS), a source of oxidative stress and possibly inducing degenerative diseases. Here, using model conditions (ultrahigh vacuum and single crystals), we unveil another process capable of converting catechols into ROSs, namely an intramolecular redox reaction catalysed by a Cu surface. We focus on a tri-catechol, the hexahydroxytriphenylene molecule, and show that this antioxidant is thereby transformed into a semiquinone, as an intermediate product, and then into an even stronger oxidant, a quinone, as final product. We argue that the transformations occur via two intramolecular redox reactions: since the Cu surface cannot oxidise the molecules, the starting catechol and the semiquinone forms each are, at the same time, self-oxidised and self-reduced. Thanks to these reactions, the quinone and semiquinone are able to interact with the substrate by readily accepting electrons donated by the substrate. Our combined experimental surface science and ab initio analysis highlights the key role played by metal nanoparticles in the development of degenerative diseases. An antioxidant catechol transforms following intramolecular redox reactions into highly reactive oxygen species, a semiquinone and a quinone, on copper.![]()
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Affiliation(s)
| | - Carlos Sánchez-Sánchez
- Materials Science Factory, Instituto de Ciencia de Materiales de Madrid-CSIC C/Sor Juana Inés de la Cruz 3 Madrid 28049 Spain
| | - Frédéric Chérioux
- Univ. Bourgogne Franche-Comté, FEMTO-ST, CNRS, UFC 15B avenue des Montboucons F-25030 Besançon Cedex France
| | - Jose Ignacio Martínez
- Materials Science Factory, Instituto de Ciencia de Materiales de Madrid-CSIC C/Sor Juana Inés de la Cruz 3 Madrid 28049 Spain
| | - José Abad
- Departamento de F, ica Aplicada, Universidad Politécnica de Cartagena Calle Doctor Fleming, s/n 30202 Cartagena Spain
| | - Luca Floreano
- Laboratorio TASC, CNR-IOM Basovizza SS-14, Km 163.5 34149 Trieste Italy
| | - Alberto Verdini
- Laboratorio TASC, CNR-IOM Basovizza SS-14, Km 163.5 34149 Trieste Italy
| | - Albano Cossaro
- Laboratorio TASC, CNR-IOM Basovizza SS-14, Km 163.5 34149 Trieste Italy
| | | | - Valérie Guisset
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut NEEL 38000 Grenoble France
| | - Philippe David
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut NEEL 38000 Grenoble France
| | - Simone Lisi
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut NEEL 38000 Grenoble France
| | - José Angel Martín Gago
- Materials Science Factory, Instituto de Ciencia de Materiales de Madrid-CSIC C/Sor Juana Inés de la Cruz 3 Madrid 28049 Spain.,Institute of Physics, Academy of Sciences of the Czech Republic 162 00 Praha Czech Republic
| | - Johann Coraux
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut NEEL 38000 Grenoble France
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20
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Kang H, Kong GD, Byeon SE, Yang S, Kim JW, Yoon HJ. Interplay of Fermi Level Pinning, Marcus Inverted Transport, and Orbital Gating in Molecular Tunneling Junctions. J Phys Chem Lett 2020; 11:8597-8603. [PMID: 32976711 DOI: 10.1021/acs.jpclett.0c02509] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
This Letter examines the interplay of important tunneling mechanisms-Fermi level pinning, Marcus inverted transport, and orbital gating-in a molecular rectifier. The temperature dependence of the rectifying molecular junction containing 2,2'-bipyridyl terminated n-alkanethiolate was investigated. A bell-shaped trend of activation energy as a function of applied bias evidenced the dominant occurrence of unusual Marcus inverted transport, while retention of rectification at low temperatures implied that the rectification obeyed the resonant tunneling regime. The results allowed reconciling two separately developed transport models, Marcus-Landauer energetics and Fermi level pinning-based rectification. Our work shows that the internal orbital gating can be substituted with the pinning effect, which pushes the transport mechanism into the Marcus inverted regime.
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Affiliation(s)
- Hungu Kang
- Department of Chemistry, Korea University, Seoul 02841, Korea
| | - Gyu Don Kong
- Department of Chemistry, Korea University, Seoul 02841, Korea
| | - Seo Eun Byeon
- Department of Chemistry, Korea University, Seoul 02841, Korea
| | - Sena Yang
- Korea Research Institute of Standards and Science (KRISS), Daejeon 34113, Korea
| | - Jeong Won Kim
- Korea Research Institute of Standards and Science (KRISS), Daejeon 34113, Korea
| | - Hyo Jae Yoon
- Department of Chemistry, Korea University, Seoul 02841, Korea
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21
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Chen X, Salim T, Zhang Z, Yu X, Volkova I, Nijhuis CA. Large Increase in the Dielectric Constant and Partial Loss of Coherence Increases Tunneling Rates across Molecular Wires. ACS APPLIED MATERIALS & INTERFACES 2020; 12:45111-45121. [PMID: 32897683 DOI: 10.1021/acsami.0c11106] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Although the dielectric behavior of monolayers is important in a large range of applications, its role in charge transport studies involving molecular junctions is largely ignored. This paper describes a large increase in the relative static dielectric constant (εr) by simply increasing the thickness of well-organized monolayers of oligoglycine and oligo(ethylene glycol) from 7 up to 14. The resulting large capacitance of 3.5-5.1 μF/cm2 is thickness-independent, which is highly attractive for field-effect transistor applications. This increase of εr results in a linear increase of the thermal activation energy by a factor of 6, which suggests that the mechanism of charge transport gradually changes from coherent to (partially) incoherent tunneling. The comparisons of oligoglycine (which readily forms hydrogen bonds with neighboring molecules) and methyl terminated oligo(ethylene glycol) (which lacks hydrogen bond donors) monolayers, kinetic isotope effects, and relative humidity-dependent measurements all indicate the importance of strong hydrogen bonds involving ionic species and strongly bonded water in the unusual dielectric behavior and the incoherent tunneling mechanism. This partial loss of coherence of the charge carriers can explain the unusually small tunneling decay coefficients across long molecular wires, and the length-dependent increase of εr of monolayers opens up interesting new applications.
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Affiliation(s)
- Xiaoping Chen
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
| | - Teddy Salim
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Ziyu Zhang
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
| | - Xiaojiang Yu
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore 117603, Singapore
| | - Ira Volkova
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
| | - Christian A Nijhuis
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, 6 Science Drive 2, Singapore 117546, Singapore
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22
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Wang Q, Chen MT, Franco-Cañellas A, Shen B, Geiger T, F. Bettinger H, Schreiber F, Salzmann I, Gerlach A, Duhm S. Impact of fluorination on interface energetics and growth of pentacene on Ag(111). BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2020; 11:1361-1370. [PMID: 32974114 PMCID: PMC7492695 DOI: 10.3762/bjnano.11.120] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 08/19/2020] [Indexed: 05/26/2023]
Abstract
We studied the structural and electronic properties of 2,3,9,10-tetrafluoropentacene (F4PEN) on Ag(111) via X-ray standing waves (XSW), low-energy electron diffraction (LEED) as well as ultraviolet and X-ray photoelectron spectroscopy (UPS and XPS). XSW revealed that the adsorption distances of F4PEN in (sub)monolayers on Ag(111) were 3.00 Å for carbon atoms and 3.05 Å for fluorine atoms. The F4PEN monolayer was essentially lying on Ag(111), and multilayers adopted π-stacking. Our study shed light not only on the F4PEN-Ag(111) interface but also on the fundamental adsorption behavior of fluorinated pentacene derivatives on metals in the context of interface energetics and growth mode.
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Affiliation(s)
- Qi Wang
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Meng-Ting Chen
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices and Joint International Research Laboratory of Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123, People’s Republic of China
| | - Antoni Franco-Cañellas
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Bin Shen
- Institut für Organische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Thomas Geiger
- Institut für Organische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Holger F. Bettinger
- Institut für Organische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Frank Schreiber
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Ingo Salzmann
- Department of Physics, Department of Chemistry & Biochemistry, Concordia University, 7141 Sherbrooke St. West, Montreal, Quebec H4B 1R6, Canada
| | - Alexander Gerlach
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Steffen Duhm
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices and Joint International Research Laboratory of Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123, People’s Republic of China
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23
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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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24
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Ajayakumar MR, Moreno C, Alcón I, Illas F, Rovira C, Veciana J, Bromley ST, Mugarza A, Mas-Torrent M. Neutral Organic Radical Formation by Chemisorption on Metal Surfaces. J Phys Chem Lett 2020; 11:3897-3904. [PMID: 32343903 DOI: 10.1021/acs.jpclett.0c00269] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Organic radical monolayers (r-MLs) bonded to metal surfaces are potential materials for the development of molecular (spin)electronics. Typically, stable radicals bearing surface anchoring groups are used to generate r-MLs. Following a recent theoretical proposal based on a model system, we report the first experimental realization of a metal surface-induced r-ML, where a rationally chosen closed-shell precursor 3,5-dichloro-4-[bis(2,4,6-trichlorophenyl)methylen]cyclohexa-2,5-dien-1-one (1) transforms into a stable neutral open-shell species (1•) via chemisorption on the Ag(111) surface. X-ray photoelectron spectroscopy reveals that the >C═O group of 1 reacts with the surface, forming a C-O-Ag linkage that induces an electronic rearrangement that transforms 1 to 1•. We further show that surface reactivity is an important factor in this process whereby Au(111) is inert towards 1, whereas the Cu(111) surface leads to dehalogenation reactions. The radical nature of the Ag(111)-bound monolayer was further confirmed by angle-resolved photoelectron spectroscopy and electronic structure calculations, which provide evidence of the emergence of the singly occupied molecular orbital (SOMO) of 1•.
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Affiliation(s)
- M R Ajayakumar
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC) and Networking Research Center on Bioengineering Biomaterials and Nanomedicine (CIBER-BBN), Campus de la UAB, E-08193 Bellaterra, Spain
| | - César Moreno
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Isaac Alcón
- Departament de Ciència de Materials i Quı́mica Fı́sica & Institut de Quı́mica Teòrica i Computacional (IQTCUB), Universitat de Barcelona, E-08028 Barcelona, Spain
| | - Francesc Illas
- Departament de Ciència de Materials i Quı́mica Fı́sica & Institut de Quı́mica Teòrica i Computacional (IQTCUB), Universitat de Barcelona, E-08028 Barcelona, Spain
| | - Concepció Rovira
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC) and Networking Research Center on Bioengineering Biomaterials and Nanomedicine (CIBER-BBN), Campus de la UAB, E-08193 Bellaterra, Spain
| | - Jaume Veciana
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC) and Networking Research Center on Bioengineering Biomaterials and Nanomedicine (CIBER-BBN), Campus de la UAB, E-08193 Bellaterra, Spain
| | - Stefan T Bromley
- Departament de Ciència de Materials i Quı́mica Fı́sica & Institut de Quı́mica Teòrica i Computacional (IQTCUB), Universitat de Barcelona, E-08028 Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), E-08010 Barcelona, Spain
| | - Aitor Mugarza
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193 Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), E-08010 Barcelona, Spain
| | - Marta Mas-Torrent
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC) and Networking Research Center on Bioengineering Biomaterials and Nanomedicine (CIBER-BBN), Campus de la UAB, E-08193 Bellaterra, Spain
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25
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Wang Q, Franco-Cañellas A, Yang J, Hausch J, Struzek S, Chen M, Thakur PK, Gerlach A, Duhm S, Schreiber F. Heteromolecular Bilayers on a Weakly Interacting Substrate: Physisorptive Bonding and Molecular Distortions of Copper-Hexadecafluorophthalocyanine. ACS APPLIED MATERIALS & INTERFACES 2020; 12:14542-14551. [PMID: 32109044 DOI: 10.1021/acsami.9b22812] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Heteromolecular bilayers of π-conjugated organic molecules on metals, considered as model systems for more complex thin film heterostructures, are investigated with respect to their structural and electronic properties. By exploring the influence of the organic-metal interaction strength in bilayer systems, we determine the molecular arrangement in the physisorptive regime for copper-hexadecafluorophthalocyanine (F16CuPc) on Au(111) with intermediate layers of 5,7,12,14-pentacenetetrone and perylene-3,4,9,10-tetracarboxylic diimide. Using the X-ray standing wave technique to distinguish the different molecular layers, we show that these two bilayers are ordered following their deposition sequence. Surprisingly, F16CuPc as the second layer within the heterostructures exhibits an inverted intramolecular distortion compared to its monolayer structure.
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Affiliation(s)
- Qi Wang
- Institut für Angewandte Physik, Universität Tübingen, 72076 Tübingen, Germany
| | | | - Jiacheng Yang
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices and Joint International Research Laboratory of Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123, People's Republic of China
| | - Julian Hausch
- Institut für Angewandte Physik, Universität Tübingen, 72076 Tübingen, Germany
| | - Samuel Struzek
- Institut für Angewandte Physik, Universität Tübingen, 72076 Tübingen, Germany
| | - Mengting Chen
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices and Joint International Research Laboratory of Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123, People's Republic of China
| | - Pardeep Kumar Thakur
- Diamond Light Source, Harwell Science and Innovation Campus, Oxfordshire OX11 0DE, United Kingdom
| | - Alexander Gerlach
- Institut für Angewandte Physik, Universität Tübingen, 72076 Tübingen, Germany
| | - Steffen Duhm
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices and Joint International Research Laboratory of Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123, People's Republic of China
| | - Frank Schreiber
- Institut für Angewandte Physik, Universität Tübingen, 72076 Tübingen, Germany
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26
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Schweicher G, Garbay G, Jouclas R, Vibert F, Devaux F, Geerts YH. Molecular Semiconductors for Logic Operations: Dead-End or Bright Future? ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1905909. [PMID: 31965662 DOI: 10.1002/adma.201905909] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 11/18/2019] [Indexed: 05/26/2023]
Abstract
The field of organic electronics has been prolific in the last couple of years, leading to the design and synthesis of several molecular semiconductors presenting a mobility in excess of 10 cm2 V-1 s-1 . However, it is also started to recently falter, as a result of doubtful mobility extractions and reduced industrial interest. This critical review addresses the community of chemists and materials scientists to share with it a critical analysis of the best performing molecular semiconductors and of the inherent charge transport physics that takes place in them. The goal is to inspire chemists and materials scientists and to give them hope that the field of molecular semiconductors for logic operations is not engaged into a dead end. To the contrary, it offers plenty of research opportunities in materials chemistry.
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Affiliation(s)
- Guillaume Schweicher
- Laboratoire de chimie des polymères, Faculté des Sciences, Université Libre de Bruxelles (ULB) Boulevard du Triomphe, Brussels, 1050, Belgium
- Optoelectronics Group, Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge, CB3 0HE, UK
| | - Guillaume Garbay
- Laboratoire de chimie des polymères, Faculté des Sciences, Université Libre de Bruxelles (ULB) Boulevard du Triomphe, Brussels, 1050, Belgium
| | - Rémy Jouclas
- Laboratoire de chimie des polymères, Faculté des Sciences, Université Libre de Bruxelles (ULB) Boulevard du Triomphe, Brussels, 1050, Belgium
| | - François Vibert
- Laboratoire de chimie des polymères, Faculté des Sciences, Université Libre de Bruxelles (ULB) Boulevard du Triomphe, Brussels, 1050, Belgium
| | - Félix Devaux
- Laboratoire de chimie des polymères, Faculté des Sciences, Université Libre de Bruxelles (ULB) Boulevard du Triomphe, Brussels, 1050, Belgium
| | - Yves H Geerts
- Laboratoire de chimie des polymères, Faculté des Sciences, Université Libre de Bruxelles (ULB) Boulevard du Triomphe, Brussels, 1050, Belgium
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27
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Zhang R, Liu J, Gao Y, Hua M, Xia B, Knecht P, Papageorgiou AC, Reichert J, Barth JV, Xu H, Huang L, Lin N. On‐surface Synthesis of a Semiconducting 2D Metal–Organic Framework Cu
3
(C
6
O
6
) Exhibiting Dispersive Electronic Bands. Angew Chem Int Ed Engl 2020; 59:2669-2673. [DOI: 10.1002/anie.201913698] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Indexed: 11/06/2022]
Affiliation(s)
- Ran Zhang
- Department of PhysicsThe Hong Kong University of Science and Technology Hong Kong SAR China
| | - Jing Liu
- Department of PhysicsThe Hong Kong University of Science and Technology Hong Kong SAR China
| | - Yifan Gao
- Department of PhysicsThe Hong Kong University of Science and Technology Hong Kong SAR China
- Department of PhysicsSouthern University of Science and Technology Shenzhen Guangdong 518055 China
| | - Muqing Hua
- Department of PhysicsThe Hong Kong University of Science and Technology Hong Kong SAR China
| | - Bowen Xia
- Department of PhysicsThe Hong Kong University of Science and Technology Hong Kong SAR China
- Department of PhysicsSouthern University of Science and Technology Shenzhen Guangdong 518055 China
| | - Peter Knecht
- Physics Department E20Technical University of Munich 85748 Garching Germany
| | | | - Joachim Reichert
- Physics Department E20Technical University of Munich 85748 Garching Germany
| | - Johannes V. Barth
- Physics Department E20Technical University of Munich 85748 Garching Germany
| | - Hu Xu
- Department of PhysicsSouthern University of Science and Technology Shenzhen Guangdong 518055 China
| | - Li Huang
- Department of PhysicsSouthern University of Science and Technology Shenzhen Guangdong 518055 China
| | - Nian Lin
- Department of PhysicsThe Hong Kong University of Science and Technology Hong Kong SAR China
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28
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On‐surface Synthesis of a Semiconducting 2D Metal–Organic Framework Cu
3
(C
6
O
6
) Exhibiting Dispersive Electronic Bands. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201913698] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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29
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Yang X, Egger L, Fuchsberger J, Unzog M, Lüftner D, Hajek F, Hurdax P, Jugovac M, Zamborlini G, Feyer V, Koller G, Puschnig P, Tautz FS, Ramsey MG, Soubatch S. Coexisting Charge States in a Unary Organic Monolayer Film on a Metal. J Phys Chem Lett 2019; 10:6438-6445. [PMID: 31573816 DOI: 10.1021/acs.jpclett.9b02231] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The electronic and geometric structures of tetracene films on Ag(110) and Cu(110) have been studied with photoemission tomography and compared to that of pentacene. Despite similar energy level alignment of the two oligoacenes on these surfaces revealed by conventional ultraviolet photoelectron spectroscopy, the momentum-space resolved photoemission tomography reveals a significant difference in both structural and electronic properties of tetracene and pentacene films. Particularly, the saturated monolayer of tetracene on Ag(110) is found to consist of two molecular species that, despite having the same orientation, are electronically very different-while one molecule remains neutral, another is charged because of electron donation from the substrate.
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Affiliation(s)
- Xiaosheng Yang
- 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
| | - Larissa Egger
- Institute of Physics , University of Graz , NAWI Graz, 8010 Graz , Austria
| | - Jana Fuchsberger
- Institute of Physics , University of Graz , NAWI Graz, 8010 Graz , Austria
| | - Martin Unzog
- Institute of Physics , University of Graz , NAWI Graz, 8010 Graz , Austria
| | - Daniel Lüftner
- Institute of Physics , University of Graz , NAWI Graz, 8010 Graz , Austria
| | - Felix Hajek
- Institute of Physics , University of Graz , NAWI Graz, 8010 Graz , Austria
| | - Philipp Hurdax
- Institute of Physics , University of Graz , NAWI Graz, 8010 Graz , Austria
| | - Matteo Jugovac
- Peter Grünberg Institut (PGI-6) , Forschungszentrum Jülich , 52425 Jülich , Germany
| | - Giovanni Zamborlini
- Peter Grünberg Institut (PGI-6) , Forschungszentrum Jülich , 52425 Jülich , Germany
| | - Vitaliy Feyer
- Peter Grünberg Institut (PGI-6) , Forschungszentrum Jülich , 52425 Jülich , Germany
| | - Georg Koller
- Institute of Physics , University of Graz , NAWI Graz, 8010 Graz , Austria
| | - Peter Puschnig
- Institute of Physics , University of Graz , NAWI Graz, 8010 Graz , Austria
| | - 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, 8010 Graz , Austria
| | - 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
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30
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Chen MT, Hofmann OT, Gerlach A, Bröker B, Bürker C, Niederhausen J, Hosokai T, Zegenhagen J, Vollmer A, Rieger R, Müllen K, Schreiber F, Salzmann I, Koch N, Zojer E, Duhm S. Energy-level alignment at strongly coupled organic-metal interfaces. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:194002. [PMID: 30673641 DOI: 10.1088/1361-648x/ab0171] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Energy-level alignment at organic-metal interfaces plays a crucial role for the performance of organic electronic devices. However, reliable models to predict energetics at strongly coupled interfaces are still lacking. We elucidate contact formation of 1,2,5,6,9,10-coronenehexone (COHON) to the (1 1 1)-surfaces of coinage metals by means of ultraviolet photoelectron spectroscopy, x-ray photoelectron spectroscopy, the x-ray standing wave technique, and density functional theory calculations. While for low COHON thicknesses, the work-functions of the systems vary considerably, for thicker organic films Fermi-level pinning leads to identical work functions of 5.2 eV for all COHON-covered metals irrespective of the pristine substrate work function and the interfacial interaction strength.
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Affiliation(s)
- Meng-Ting Chen
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices and Joint International Research Laboratory of Carbon-Based Functional Materials and Devices, Soochow University, 199 Ren-Ai Road, Suzhou 215123, People's Republic of China
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31
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Stadtmüller B, Grad L, Seidel J, Haag F, Haag N, Cinchetti M, Aeschlimann M. Modification of Pb quantum well states by the adsorption of organic molecules. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:134005. [PMID: 30625428 DOI: 10.1088/1361-648x/aafcf5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The successful implementation of nanoscale materials in next generation optoelectronic devices crucially depends on our ability to functionalize and design low dimensional materials according to the desired field of application. Recently, organic adsorbates have revealed an enormous potential to alter the occupied surface band structure of tunable materials by the formation of tailored molecule-surface bonds. Here, we extend this concept of adsorption-induced surface band structure engineering to the unoccupied part of the surface band structure. This is achieved by our comprehensive investigation of the unoccupied band structure of a lead (Pb) monolayer film on the Ag(1 1 1) surface prior and after the adsorption of one monolayer of the aromatic molecule 3,4,9,10-perylene-tetracarboxylic-dianhydride (PTCDA). Using two-photon momentum microscopy, we show that the unoccupied states of the Pb/Ag(1 1 1) bilayer system are dominated by a parabolic quantum well state (QWS) in the center of the surface Brillouin zone with Pb p[Formula: see text] orbital character and a side band with almost linear dispersion showing Pb p[Formula: see text] orbital character. After the adsorption of PTCDA, the Pb side band remains completely unaffected while the signal of the Pb QWS is fully suppressed. This adsorption induced change in the unoccupied Pb band structure coincides with an interfacial charge transfer from the Pb layer into the PTCDA molecule. We propose that this charge transfer and the correspondingly vertical (partially chemical) interaction across the PTCDA/Pb interface suppresses the existence of the QWS in the Pb layer. Our results hence unveil a new possibility to orbital selectively tune and control the entire surface band structure of low dimensional systems by the adsorption of organic molecules.
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Affiliation(s)
- Benjamin Stadtmüller
- Department of Physics and OPTIMAS Research Center, TU Kaiserslautern, Erwin-Schrödinger-Strasse 46, 67663 Kaiserslautern, Germany. Graduate School of Excellence Materials Science in Mainz, Erwin-Schrödinger-Strasse 46, 67663 Kaiserslautern, Germany
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32
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Kong W, Li W, Liu C, Liu H, Miao J, Wang W, Chen S, Hu M, Li D, Amini A, Yang S, Wang J, Xu B, Cheng C. Organic Monomolecular Layers Enable Energy-Level Matching for Efficient Hole Transporting Layer Free Inverted Perovskite Solar Cells. ACS NANO 2019; 13:1625-1634. [PMID: 30673271 DOI: 10.1021/acsnano.8b07627] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
High-efficiency hole transport layer free perovskite solar cells (HTL-free PSCs) with economical and simplified device structure can greatly facilitate the commercialization of PSCs. However, eliminating the key HTL in PSCs results usually in a severe efficiency loss and poor carrier transfer due to the energy-level mismatching at the indium tin oxide (ITO)/perovskite interface. In this study, we solve this issue by introducing an organic monomolecular layer (ML) to raise the effective work function of ITO with the assistance of an interface dipole created by Sn-N bonds. The energy-level alignment at the ITO/perovskite interface is optimized with a barrier-free contact, which favors efficient charge transfer and suppressed nonradiative carrier recombination. The HTL-free PSCs based on the ML-modified ITO yield an efficiency of 19.4%, much higher than those of HTL-free PSCs on bare ITO (10.26%), comparable to state-of-the-art PSCs with a HTL. This study provides an in-depth understanding of the mechanism of interfacial energy-level alignment and facilitates the design of advanced interfacial materials for simplified and efficient PSC devices.
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Affiliation(s)
- Weiguang Kong
- Department of Materials Science and Engineering , Southern University of Science and Technology , Shenzhen , Guangdong Province 518055 , China
- Hebei Key Laboratory of Optic-electronic Information Materials, National-Local Joint Engineering Laboratory of New Energy Photoelectric Devices, College of Physics Science and Technology , Hebei University , Baoding 071002 , China
- Department of Physics , Wuhan University , Wuhan , Hubei Province 430072 , China
| | - Wang Li
- Department of Materials Science and Engineering , Southern University of Science and Technology , Shenzhen , Guangdong Province 518055 , China
| | - Changwen Liu
- Department of Materials Science and Engineering , Southern University of Science and Technology , Shenzhen , Guangdong Province 518055 , China
| | - Hui Liu
- Department of Materials Science and Engineering , Southern University of Science and Technology , Shenzhen , Guangdong Province 518055 , China
| | - Jun Miao
- Department of Materials Science and Engineering , Southern University of Science and Technology , Shenzhen , Guangdong Province 518055 , China
| | - Weijun Wang
- Department of Materials Science and Engineering , Southern University of Science and Technology , Shenzhen , Guangdong Province 518055 , China
| | - Shi Chen
- Department of Materials Science and Engineering , Southern University of Science and Technology , Shenzhen , Guangdong Province 518055 , China
| | - Manman Hu
- Department of Materials Science and Engineering , Southern University of Science and Technology , Shenzhen , Guangdong Province 518055 , China
| | - Dedi Li
- Department of Materials Science and Engineering , Southern University of Science and Technology , Shenzhen , Guangdong Province 518055 , China
| | - Abbas Amini
- Center for Infrastructure Engineering , Western Sydney University , Kingswood , NSW 2751 , Australia
- Department of Mechanical Engineering , Australian College of Kuwait , Mishref , Kuwait
| | - Shaopeng Yang
- Hebei Key Laboratory of Optic-electronic Information Materials, National-Local Joint Engineering Laboratory of New Energy Photoelectric Devices, College of Physics Science and Technology , Hebei University , Baoding 071002 , China
| | - Jianbo Wang
- Department of Physics , Wuhan University , Wuhan , Hubei Province 430072 , China
| | - Baomin Xu
- Department of Materials Science and Engineering , Southern University of Science and Technology , Shenzhen , Guangdong Province 518055 , China
| | - Chun Cheng
- Department of Materials Science and Engineering , Southern University of Science and Technology , Shenzhen , Guangdong Province 518055 , China
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33
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Erker S, Hofmann OT. Fractional and Integer Charge Transfer at Semiconductor/Organic Interfaces: The Role of Hybridization and Metallicity. J Phys Chem Lett 2019; 10:848-854. [PMID: 30732451 DOI: 10.1021/acs.jpclett.8b03857] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Inorganic/organic interfaces show two phenomenologically different types of charge transfer: On inert substrates, charge is localized, leading to a coexistence of neutral and charged molecules. Conversely, on metals, which have more available charge carriers and a larger propensity to hybridize, the charge is homogeneously delocalized. In this contribution, we use hybrid density functional theory to study the adsorption of the strong electron acceptor F4TCNQ on ZnO(10-10) as a function of the substrate's doping concentration. This system undergoes a joint charge donation/backdonation reaction. Because only the former is driven by hybridization, this allows us to study the impact of hybridization and the availability of charge carriers separately. We find that here both charge-transfer types are simultaneously at work. Whereas hybridization determines the charge localization, the charge-carrier concentration determines the amount of transferred charge. Consequently, at low doping concentrations, most of the electron acceptors become slightly positively, rather than negatively, charged.
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Affiliation(s)
- Simon Erker
- Institute of Solid State Physics , Graz University of Technology, NAWI Graz , Petersgasse 16 , 8010 Graz , Austria
| | - Oliver T Hofmann
- Institute of Solid State Physics , Graz University of Technology, NAWI Graz , Petersgasse 16 , 8010 Graz , Austria
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34
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Breuer T, Geiger T, Bettinger HF, Witte G. Diels-Alder adduct formation at solid interfaces between fullerenes and acenes. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:034003. [PMID: 30524049 DOI: 10.1088/1361-648x/aaf01b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Understanding organic-organic interfaces is rather challenging due to their large complexity regarding morphology, molecular orientation at the interface, interdiffusion, and energetics. One additional important but often neglected aspect are chemical reactions occuring at such interfaces. For solid interfaces between pentacene and Buckminster-Fullerene (C60) recently very efficient Diels-Alder (D-A) adduct formation has been reported. Considering the importance of pentacene/C60 as prototypical donor-acceptor combination to study fundamental processes in organic photovoltaics, understanding this effect is essential. In this work, we provide detailed NEXAFS-based investigations with respect to the temperature-dependence and reaction zone depth of this effect. Moreover, we widely vary the interface morphology and observe that the D-A adduct formation is most efficient for bulk heterojunctions of pentacene and C60. By also investigating further material combinations such as PEN/C60-PCBM and interfaces between C60 and functionalized acenes, we observe trends for the occurrence of the D-A adduct formation correlated with the different chemical properties of the involved compounds.
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Affiliation(s)
- T Breuer
- Department of Physics, Molekulare Festkörperphysik, Philipps-Universität Marburg, 35032, Marburg, Germany
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35
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Colazzo L, Mohammed MSG, Dorel R, Nita P, García Fernández C, Abufager P, Lorente N, Echavarren AM, de Oteyza DG. On-surface synthesis of heptacene on Ag(001) from brominated and non-brominated tetrahydroheptacene precursors. Chem Commun (Camb) 2018; 54:10260-10263. [PMID: 30152499 PMCID: PMC6136266 DOI: 10.1039/c8cc04402c] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Achieving the Ag(001)-supported synthesis of heptacene from two related reactants reveals the effect of the presence of Br atoms on the reaction process.
Achieving the Ag(001)-supported synthesis of heptacene from two related reactants reveals the effect of the presence of Br atoms on the reaction process. The properties of reactants, intermediates and end-products are further characterized by scanning tunneling microscopy and spectroscopy.
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Affiliation(s)
- Luciano Colazzo
- Donostia International Physics Center (DIPC), 20018 San Sebastián, Spain.
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36
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Senkovskiy BV, Usachov DY, Fedorov AV, Marangoni T, Haberer D, Tresca C, Profeta G, Caciuc V, Tsukamoto S, Atodiresei N, Ehlen N, Chen C, Avila J, Asensio MC, Varykhalov AY, Nefedov A, Wöll C, Kim TK, Hoesch M, Fischer FR, Grüneis A. Boron-Doped Graphene Nanoribbons: Electronic Structure and Raman Fingerprint. ACS NANO 2018; 12:7571-7582. [PMID: 30004663 DOI: 10.1021/acsnano.8b04125] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We investigate the electronic and vibrational properties of bottom-up synthesized aligned armchair graphene nanoribbons of N = 7 carbon atoms width periodically doped by substitutional boron atoms (B-7AGNRs). Using angle-resolved photoemission spectroscopy and density functional theory calculations, we find that the dopant-derived valence and conduction band states are notably hybridized with electronic states of Au substrate and spread in energy. The interaction with the substrate leaves the bands with pure carbon character rather unperturbed. This results in an identical effective mass of ≈0.2 m0 for the next-highest valence band compared with pristine 7AGNRs. We probe the phonons of B-7AGNRs by ultrahigh-vacuum (UHV) Raman spectroscopy and reveal the existence of characteristic splitting and red shifts in Raman modes due to the presence of substitutional boron atoms. Comparing the Raman spectra for three visible lasers (red, green, and blue), we find that interaction with gold suppresses the Raman signal from B-7AGNRs and the energy of the green laser (2.33 eV) is closer to the resonant E22 transition. The hybridized electronic structure of the B-7AGNR-Au interface is expected to improve electrical characteristics of contacts between graphene nanoribbon and Au. The Raman fingerprint allows the easy identification of B-7AGNRs, which is particularly useful for device fabrication.
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Affiliation(s)
- Boris V Senkovskiy
- II. Physikalisches Institut, Universität zu Köln , Zülpicher Strasse 77 , 50937 Köln , Germany
| | - Dmitry Yu Usachov
- St. Petersburg State University , 7/9 Universitetskaya nab. , Saint Petersburg 199034 , Russia
| | - Alexander V Fedorov
- II. Physikalisches Institut, Universität zu Köln , Zülpicher Strasse 77 , 50937 Köln , Germany
- St. Petersburg State University , 7/9 Universitetskaya nab. , Saint Petersburg 199034 , Russia
- IFW Dresden , P.O. Box 270116, D-01171 Dresden , Germany
| | - Tomas Marangoni
- Department of Chemistry , University of California , Tan Hall 680 , Berkeley , California 94720 , United States
| | - Danny Haberer
- Department of Chemistry , University of California , Tan Hall 680 , Berkeley , California 94720 , United States
| | - Cesare Tresca
- Department of Physical and Chemical Sciences and SPIN-CNR , University of L'Aquila , Via Vetoio 10 , I-67100 Coppito , Italy
- Institut des Nanosciences de Paris, Sorbonne Universités-UPMC univ Paris 6 and CNRS-UMR 7588 , 4 place Jussieu , F-75252 Paris , France
| | - Gianni Profeta
- Department of Physical and Chemical Sciences and SPIN-CNR , University of L'Aquila , Via Vetoio 10 , I-67100 Coppito , Italy
| | - Vasile Caciuc
- Peter Grünberg Institut (PGI-1) and Institute for Advanced Simulation (IAS-1) , Forschungszentrum Jülich and JARA , D-52425 Jülich , Germany
| | - Shigeru Tsukamoto
- Peter Grünberg Institut (PGI-1) and Institute for Advanced Simulation (IAS-1) , Forschungszentrum Jülich and JARA , D-52425 Jülich , Germany
| | - Nicolae Atodiresei
- Peter Grünberg Institut (PGI-1) and Institute for Advanced Simulation (IAS-1) , Forschungszentrum Jülich and JARA , D-52425 Jülich , Germany
| | - Niels Ehlen
- II. Physikalisches Institut, Universität zu Köln , Zülpicher Strasse 77 , 50937 Köln , Germany
| | - Chaoyu Chen
- ANTARES Beamline , Synchrotron SOLEIL & Universite Paris-Saclay, L' Orme des Merisiers , Saint Aubin-BP 48 , 91192 Gif sur Yvette Cedex , France
| | - José Avila
- ANTARES Beamline , Synchrotron SOLEIL & Universite Paris-Saclay, L' Orme des Merisiers , Saint Aubin-BP 48 , 91192 Gif sur Yvette Cedex , France
| | - Maria C Asensio
- ANTARES Beamline , Synchrotron SOLEIL & Universite Paris-Saclay, L' Orme des Merisiers , Saint Aubin-BP 48 , 91192 Gif sur Yvette Cedex , France
| | | | - Alexei Nefedov
- Institut für Funktionelle Grenzflächen (IFG), Karlsruher Institut für Technologie (KIT) , Hermann-von-Helmholtz-Platz 1 , 76344 Eggenstein-Leopoldshafen , Germany
| | - Christof Wöll
- Institut für Funktionelle Grenzflächen (IFG), Karlsruher Institut für Technologie (KIT) , Hermann-von-Helmholtz-Platz 1 , 76344 Eggenstein-Leopoldshafen , Germany
| | - Timur K Kim
- Diamond Light Source, Harwell Campus , Didcot , OX11 0DE , United Kingdom
| | - Moritz Hoesch
- Diamond Light Source, Harwell Campus , Didcot , OX11 0DE , United Kingdom
- DESY Photon Science, Deutsches Elektronen-Synchrotron , Notkestrasse 85 , 22607 Hamburg , Germany
| | - Felix R Fischer
- Department of Chemistry , University of California , Tan Hall 680 , Berkeley , California 94720 , United States
- Materials Science Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
- Kavli Energy Nanosciences Institute at the University of California Berkeley and Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Alexander Grüneis
- II. Physikalisches Institut, Universität zu Köln , Zülpicher Strasse 77 , 50937 Köln , Germany
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37
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Goronzy DP, Ebrahimi M, Rosei F, Fang Y, De Feyter S, Tait SL, Wang C, Beton PH, Wee ATS, Weiss PS, Perepichka DF. Supramolecular Assemblies on Surfaces: Nanopatterning, Functionality, and Reactivity. ACS NANO 2018; 12:7445-7481. [PMID: 30010321 DOI: 10.1021/acsnano.8b03513] [Citation(s) in RCA: 147] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Understanding how molecules interact to form large-scale hierarchical structures on surfaces holds promise for building designer nanoscale constructs with defined chemical and physical properties. Here, we describe early advances in this field and highlight upcoming opportunities and challenges. Both direct intermolecular interactions and those that are mediated by coordinated metal centers or substrates are discussed. These interactions can be additive, but they can also interfere with each other, leading to new assemblies in which electrical potentials vary at distances much larger than those of typical chemical interactions. Earlier spectroscopic and surface measurements have provided partial information on such interfacial effects. In the interim, scanning probe microscopies have assumed defining roles in the field of molecular organization on surfaces, delivering deeper understanding of interactions, structures, and local potentials. Self-assembly is a key strategy to form extended structures on surfaces, advancing nanolithography into the chemical dimension and providing simultaneous control at multiple scales. In parallel, the emergence of graphene and the resulting impetus to explore 2D materials have broadened the field, as surface-confined reactions of molecular building blocks provide access to such materials as 2D polymers and graphene nanoribbons. In this Review, we describe recent advances and point out promising directions that will lead to even greater and more robust capabilities to exploit designer surfaces.
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Affiliation(s)
- Dominic P Goronzy
- California NanoSystems Institute , University of California, Los Angeles , Los Angeles , California 90095 , United States
- Department of Chemistry and Biochemistry , University of California, Los Angeles , Los Angeles , California 90095 , United States
| | - Maryam Ebrahimi
- INRS Centre for Energy, Materials and Telecommunications , 1650 Boul. Lionel Boulet , Varennes , Quebec J3X 1S2 , Canada
| | - Federico Rosei
- INRS Centre for Energy, Materials and Telecommunications , 1650 Boul. Lionel Boulet , Varennes , Quebec J3X 1S2 , Canada
- Institute for Fundamental and Frontier Science , University of Electronic Science and Technology of China , Chengdu 610054 , P.R. China
| | - Yuan Fang
- Department of Chemistry , McGill University , Montreal H3A 0B8 , Canada
| | - Steven De Feyter
- Department of Chemistry , KU Leuven , Celestijnenlaan 200F , Leuven 3001 , Belgium
| | - Steven L Tait
- Department of Chemistry , Indiana University , Bloomington , Indiana 47405 , United States
| | - Chen Wang
- National Center for Nanoscience and Technology , Beijing 100190 , China
| | - Peter H Beton
- School of Physics & Astronomy , University of Nottingham , Nottingham NG7 2RD , United Kingdom
| | - Andrew T S Wee
- Department of Physics , National University of Singapore , 117542 Singapore
| | - Paul S Weiss
- California NanoSystems Institute , University of California, Los Angeles , Los Angeles , California 90095 , United States
- Department of Chemistry and Biochemistry , University of California, Los Angeles , Los Angeles , California 90095 , United States
- Department of Materials Science and Engineering , University of California, Los Angeles , Los Angeles , California 90095 , United States
| | - Dmitrii F Perepichka
- California NanoSystems Institute , University of California, Los Angeles , Los Angeles , California 90095 , United States
- Department of Chemistry , McGill University , Montreal H3A 0B8 , Canada
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38
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Papageorgiou AC, Li J, Oh SC, Zhang B, Sağlam Ö, Guo Y, Reichert J, Marco AB, Cortizo-Lacalle D, Mateo-Alonso A, Barth JV. Tuning the ease of formation of on-surface metal-adatom coordination polymers featuring diketones. NANOSCALE 2018; 10:9561-9568. [PMID: 29745943 DOI: 10.1039/c8nr02537a] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We use pyrene-4,5,9,10-tetraketone molecules with substituents of varying bulkiness in the 2,7 positions to probe the generality and versatility of the previously reported on-surface coordination of two diketones with a single metal atom, leading to one-dimensional coordination polymers. Three different low index surfaces of group 11 metals (Cu, Ag and Au) are used to provide both the support and the metal atoms for metal-organic coordination. By real space visualisation with single molecule resolution employing scanning tunnelling microscopy we investigate the molecular self-assembly and show how this can be substantiated with the formation of metal-organic linear and cyclic oligomers, depending on the employed substrate.
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39
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Abstract
In the last decade technology has brought significant changes to our lives, including new habits and a new view on social relationships. These technological innovations are based on several factors, one of which is miniaturization. This was made possible also due to the discovery and synthesis of new materials with characteristics at the nanoscale that are designed for specific purposes. This "on purpose" approach, joined to the development of preparation and growth methods, has led to use of thin films rather than bulk materials in devices. Using thin films makes devices easier to produce, and using films for coating protects the devices and gives specific properties to surfaces. For several decades thin films, surfaces, and interfaces have been intensively investigated. Indeed, device performances rely on the optimized match of thin films of different natures, such as organic and inorganic semiconductors and metals for contacts. Surprisingly, in comparison, little attention has been devoted to the deposition of organic radicals on a substrate. This might be because these materials are considered not stable enough for evaporation. In this work, we demonstrate that it is possible to evaporate and deposit organic radicals onto well-defined surfaces under controlled conditions, without degradation. Using soft X-ray spectroscopies, performed also at synchrotrons, we investigate thin film processes, surfaces, and interfaces at the nanoscale, when organic radicals are deposited on metal and metal oxide surfaces. We suggest how to design organic radicals bearing in mind the thermodynamic factors that govern thin film stability, with the purpose of obtaining not only a chemically stable radical, but also stable thin films. We investigate the thermal and air stability of the deposited films, and we explore the influence of the surface/radical chemical bond and the role of surface defects on the magnetic moment at the interface. We find that organic radicals are physisorbed and keep their magnetic moment on inert and passivated surfaces such as Au(111) and Al2O3(112̅0) single crystals, SiO2, and ideal TiO2(110) single crystals, while defective sites such as oxygen vacancies or the presence of OH groups lead to chemisorption of the organic radicals on the surface with quenching of their magnetic moment. Our work shows that the use of X-ray based techniques represents a powerful approach to reveal the mechanisms governing complex interfaces, such as radical/metal and radical/metal-oxide, where it is important to describe both charge and spin behavior (spinterfaces). It also makes it possible to conceive new experiments to investigate the magnetic character of the thin films versus their structural properties, toward tuning the arrangement of the molecules in films. Controlling the molecular arrangement will give the opportunity to tune the mutual position and orientation of the molecules, that is, of the single magnetic moments in the films, "imprinting" their magnetic properties. A deep understanding of stable radical/inorganic spinterfaces may open the way to use radicals in solid state devices or as quantum bits with dedicated configurations, as proposed for other molecular quantum bits, and in spin-based electronics.
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Affiliation(s)
- M. Benedetta Casu
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
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40
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Song P, Guerin S, Tan SJR, Annadata HV, Yu X, Scully M, Han YM, Roemer M, Loh KP, Thompson D, Nijhuis CA. Stable Molecular Diodes Based on π-π Interactions of the Molecular Frontier Orbitals with Graphene Electrodes. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:1706322. [PMID: 29356141 DOI: 10.1002/adma.201706322] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 12/01/2017] [Indexed: 06/07/2023]
Abstract
In molecular electronics, it is important to control the strength of the molecule-electrode interaction to balance the trade-off between electronic coupling strength and broadening of the molecular frontier orbitals: too strong coupling results in severe broadening of the molecular orbitals while the molecular orbitals cannot follow the changes in the Fermi levels under applied bias when the coupling is too weak. Here, a platform based on graphene bottom electrodes to which molecules can bind via π-π interactions is reported. These interactions are strong enough to induce electronic function (rectification) while minimizing broadening of the molecular frontier orbitals. Molecular tunnel junctions are fabricated based on self-assembled monolayers (SAMs) of Fc(CH2 )11 X (Fc = ferrocenyl, X = NH2 , Br, or H) on graphene bottom electrodes contacted to eutectic alloy of gallium and indium top electrodes. The Fc units interact more strongly with graphene than the X units resulting in SAMs with the Fc at the bottom of the SAM. The molecular diodes perform well with rectification ratios of 30-40, and they are stable against bias stressing under ambient conditions. Thus, tunnel junctions based on graphene with π-π molecule-electrode coupling are promising platforms to fabricate stable and well-performing molecular diodes.
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Affiliation(s)
- Peng Song
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore
| | - Sarah Guerin
- Department of Physics, Bernal Institute, University of Limerick, Limerick, V94 T9PX, Ireland
| | - Sherman Jun Rong Tan
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore
| | - Harshini Venkata Annadata
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore
| | - Xiaojiang Yu
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore, 117603, Singapore
| | - Micheál Scully
- Department of Physics, Bernal Institute, University of Limerick, Limerick, V94 T9PX, Ireland
| | - Ying Mei Han
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore
| | - Max Roemer
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore
| | - Kian Ping Loh
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore
- Centre for Advanced 2D Materials, Graphene Research Centre, National University of Singapore, 6 Science Drive 2, Singapore, 117546, Singapore
| | - Damien Thompson
- Department of Physics, Bernal Institute, University of Limerick, Limerick, V94 T9PX, Ireland
| | - Christian A Nijhuis
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore
- Centre for Advanced 2D Materials, Graphene Research Centre, National University of Singapore, 6 Science Drive 2, Singapore, 117546, Singapore
- NUSNNI-Nanocore, National University of Singapore, Singapore, 117411, Singapore
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41
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Sierra MA, Sánchez D, Garrigues AR, Del Barco E, Wang L, Nijhuis CA. How to distinguish between interacting and noninteracting molecules in tunnel junctions. NANOSCALE 2018; 10:3904-3910. [PMID: 29423488 DOI: 10.1039/c7nr05739c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Recent experiments demonstrate a temperature control of the electric conduction through a ferrocene-based molecular junction. Here we examine the results in view of determining means to distinguish between transport through single-particle molecular levels or via transport channels split by Coulomb repulsion. Both transport mechanisms are similar in molecular junctions given the similarities between molecular intralevel energies and the charging energy. We propose an experimentally testable way to identify the main transport process. By applying a magnetic field to the molecule, we observe that an interacting theory predicts a shift of the conductance resonances of the molecule whereas in the noninteracting case each resonance is split into two peaks. The interaction model works well in explaining our experimental results obtained in a ferrocene-based single-molecule junction, where the charge degeneracy peaks shift (but do not split) under the action of an applied 7-Tesla magnetic field. This method is useful for a proper characterization of the transport properties of molecular tunnel junctions.
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Affiliation(s)
- Miguel A Sierra
- Institute for Cross-Disciplinary Physics and Complex Systems IFISC (UIB-CSIC), Palma de Mallorca, Spain.
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42
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Merino-Díez N, Garcia-Lekue A, Carbonell-Sanromà E, Li J, Corso M, Colazzo L, Sedona F, Sánchez-Portal D, Pascual JI, de Oteyza DG. Width-Dependent Band Gap in Armchair Graphene Nanoribbons Reveals Fermi Level Pinning on Au(111). ACS NANO 2017; 11:11661-11668. [PMID: 29049879 PMCID: PMC5789393 DOI: 10.1021/acsnano.7b06765] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 10/19/2017] [Indexed: 05/25/2023]
Abstract
We report the energy level alignment evolution of valence and conduction bands of armchair-oriented graphene nanoribbons (aGNR) as their band gap shrinks with increasing width. We use 4,4″-dibromo-para-terphenyl as the molecular precursor on Au(111) to form extended poly-para-phenylene nanowires, which can subsequently be fused sideways to form atomically precise aGNRs of varying widths. We measure the frontier bands by means of scanning tunneling spectroscopy, corroborating that the nanoribbon's band gap is inversely proportional to their width. Interestingly, valence bands are found to show Fermi level pinning as the band gap decreases below a threshold value around 1.7 eV. Such behavior is of critical importance to understand the properties of potential contacts in GNR-based devices. Our measurements further reveal a particularly interesting system for studying Fermi level pinning by modifying an adsorbate's band gap while maintaining an almost unchanged interface chemistry defined by substrate and adsorbate.
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Affiliation(s)
- Néstor Merino-Díez
- Donostia
International Physics Center (DIPC), 20018 Donostia-San Sebastián, Spain
- Nanoscience
Cooperative Research Center, CIC nanoGUNE, 20018 Donostia-San
Sebastián, Spain
| | - Aran Garcia-Lekue
- Donostia
International Physics Center (DIPC), 20018 Donostia-San Sebastián, Spain
- Ikerbasque, Basque Foundation for Science, 48013 Bilbao, Spain
| | | | - Jingcheng Li
- Nanoscience
Cooperative Research Center, CIC nanoGUNE, 20018 Donostia-San
Sebastián, Spain
- Materials
Physics Center, Centro de Física
de Materiales (CSIC/UPV-EHU), 20018 Donostia-San Sebastián, Spain
| | - Martina Corso
- Nanoscience
Cooperative Research Center, CIC nanoGUNE, 20018 Donostia-San
Sebastián, Spain
- Ikerbasque, Basque Foundation for Science, 48013 Bilbao, Spain
- Materials
Physics Center, Centro de Física
de Materiales (CSIC/UPV-EHU), 20018 Donostia-San Sebastián, Spain
| | - Luciano Colazzo
- Dipartimento
di Scienze Chimiche, Università di
Padova, 35131 Padova, Italy
| | - Francesco Sedona
- Dipartimento
di Scienze Chimiche, Università di
Padova, 35131 Padova, Italy
| | - Daniel Sánchez-Portal
- Donostia
International Physics Center (DIPC), 20018 Donostia-San Sebastián, Spain
- Materials
Physics Center, Centro de Física
de Materiales (CSIC/UPV-EHU), 20018 Donostia-San Sebastián, Spain
| | - Jose I. Pascual
- Nanoscience
Cooperative Research Center, CIC nanoGUNE, 20018 Donostia-San
Sebastián, Spain
- Ikerbasque, Basque Foundation for Science, 48013 Bilbao, Spain
| | - Dimas G. de Oteyza
- Donostia
International Physics Center (DIPC), 20018 Donostia-San Sebastián, Spain
- Nanoscience
Cooperative Research Center, CIC nanoGUNE, 20018 Donostia-San
Sebastián, Spain
- Ikerbasque, Basque Foundation for Science, 48013 Bilbao, Spain
- Materials
Physics Center, Centro de Física
de Materiales (CSIC/UPV-EHU), 20018 Donostia-San Sebastián, Spain
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43
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Hofmann OT, Glowatzki H, Bürker C, Rangger GM, Bröker B, Niederhausen J, Hosokai T, Salzmann I, Blum RP, Rieger R, Vollmer A, Rajput P, Gerlach A, Müllen K, Schreiber F, Zojer E, Koch N, Duhm S. Orientation-Dependent Work-Function Modification Using Substituted Pyrene-Based Acceptors. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2017; 121:24657-24668. [PMID: 29152034 PMCID: PMC5682610 DOI: 10.1021/acs.jpcc.7b08451] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 10/10/2017] [Indexed: 05/17/2023]
Abstract
The adsorption of molecular acceptors is a viable method for tuning the work function of metal electrodes. This, in turn, enables adjusting charge injection barriers between the electrode and organic semiconductors. Here, we demonstrate the potential of pyrene-tetraone (PyT) and its derivatives dibromopyrene-tetraone (Br-PyT) and dinitropyrene-tetraone (NO2-PyT) for modifying the electronic properties of Au(111) and Ag(111) surfaces. The systems are investigated by complementary theoretical and experimental approaches, including photoelectron spectroscopy, the X-ray standing wave technique, and density functional theory simulations. For some of the investigated interfaces the trends expected for Fermi-level pinning are observed, i.e., an increase of the metal work function along with increasing molecular electron affinity and the same work function for Au and Ag with monolayer acceptor coverage. Substantial deviations are, however, found for Br-PyT/Ag(111) and NO2-PyT/Ag(111), where in the latter case an adsorption-induced work function increase of as much as 1.6 eV is observed. This behavior is explained as arising from a face-on to edge-on reorientation of molecules in the monolayer. Our calculations show that for an edge-on orientation much larger work-function changes can be expected despite the prevalence of Fermi-level pinning. This is primarily ascribed to a change of the electron affinity of the adsorbate layer that results from a change of the molecular orientation. This work provides a comprehensive understanding of how changing the molecular electron affinity as well as the adsorbate structure impacts the electronic properties of electrodes.
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Affiliation(s)
- O. T. Hofmann
- Institute
of Solid State Physics, NAWI Graz, Graz
University of Technology, Petersgasse 16, 8010 Graz, Austria
- E-mail:
| | - H. Glowatzki
- Helmholtz-Zentrum
Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 15, 12489 Berlin, Germany
| | - C. Bürker
- Institut
für Angewandte Physik, Universität
Tübingen, Auf
der Morgenstelle 10, Tübingen 72076, Germany
| | - G. M. Rangger
- Institute
of Solid State Physics, NAWI Graz, Graz
University of Technology, Petersgasse 16, 8010 Graz, Austria
| | - B. Bröker
- Institut
für Physik & IRIS Adlershof, Humboldt-Universität zu Berlin, Newtonstraße 15, 12389 Berlin, Germany
| | - J. Niederhausen
- Helmholtz-Zentrum
Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 15, 12489 Berlin, Germany
| | - T. Hosokai
- National
Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
| | - I. Salzmann
- Institut
für Physik & IRIS Adlershof, Humboldt-Universität zu Berlin, Newtonstraße 15, 12389 Berlin, Germany
- The
Institute of Solid State Physics, The University
of Tokyo, Kashiwanoha
5-1-5, Kashiwa, Chiba 277-8581, Japan
| | - R.-P. Blum
- Institut
für Physik & IRIS Adlershof, Humboldt-Universität zu Berlin, Newtonstraße 15, 12389 Berlin, Germany
| | - R. Rieger
- Max Planck
Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany
| | - A. Vollmer
- Helmholtz-Zentrum
Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 15, 12489 Berlin, Germany
| | - P. Rajput
- Atomic
& Molecular Physics Division, Bhabha
Atomic Research Centre, Trombay, Mumbai 400085, India
| | - A. Gerlach
- Institut
für Angewandte Physik, Universität
Tübingen, Auf
der Morgenstelle 10, Tübingen 72076, Germany
| | - K. Müllen
- Max Planck
Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany
- Institute
of Physical Chemistry, Johannes Gutenberg
University Mainz, Duesbergweg
10-14, Mainz, Germany
| | - F. Schreiber
- Institut
für Angewandte Physik, Universität
Tübingen, Auf
der Morgenstelle 10, Tübingen 72076, Germany
| | - E. Zojer
- Institute
of Solid State Physics, NAWI Graz, Graz
University of Technology, Petersgasse 16, 8010 Graz, Austria
| | - N. Koch
- Helmholtz-Zentrum
Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 15, 12489 Berlin, Germany
- Institut
für Physik & IRIS Adlershof, Humboldt-Universität zu Berlin, Newtonstraße 15, 12389 Berlin, Germany
- Jiangsu
Key Laboratory for Carbon-Based Functional Materials & Devices
and Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, 199 Ren-Ai Road, Suzhou 215123, P.R. China
| | - S. Duhm
- Jiangsu
Key Laboratory for Carbon-Based Functional Materials & Devices
and Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, 199 Ren-Ai Road, Suzhou 215123, P.R. China
- E-mail:
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44
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Kumar A, Banerjee K, Dvorak M, Schulz F, Harju A, Rinke P, Liljeroth P. Charge-Transfer-Driven Nonplanar Adsorption of F 4TCNQ Molecules on Epitaxial Graphene. ACS NANO 2017; 11:4960-4968. [PMID: 28467831 DOI: 10.1021/acsnano.7b01599] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
π-conjugated organic molecules tend to adsorb in a planar configuration on graphene irrespective of their charge state. In contrast, here we demonstrate charging-induced strong structural relaxation of tetrafluorotetracyanoquinodimethane (F4TCNQ) on epitaxial graphene on Ir(111) (G/Ir(111)). The work function modulation over the graphene moiré unit cell causes site-selective charging of F4TCNQ. Upon charging, the molecule anchors to the face-centered cubic sites of the G/Ir(111) moiré through one or two cyano groups. The reaction is reversible and can be triggered on a single molecule by moving it between different adsorption sites. We introduce a model taking into account the trade-off between tilt-induced charging and reduced van der Waals interactions, which provides a general framework for understanding charging-induced structural relaxation on weakly interacting substrates. In addition, we argue that the partial sp3 rehybridization of the underlying graphene and the possible bonding mechanism between the cyano groups and the graphene substrate are also relevant for the complete understanding of the experiments. These results provide insight into molecular charging on graphene, and they are directly relevant for potential device applications where the use of molecules has been suggested for doping and band structure engineering.
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Affiliation(s)
- Avijit Kumar
- Department of Applied Physics and ‡COMP/Department of Applied Physics, Aalto University School of Science , 00076 Aalto, Finland
| | - Kaustuv Banerjee
- Department of Applied Physics and ‡COMP/Department of Applied Physics, Aalto University School of Science , 00076 Aalto, Finland
| | - Marc Dvorak
- Department of Applied Physics and ‡COMP/Department of Applied Physics, Aalto University School of Science , 00076 Aalto, Finland
| | - Fabian Schulz
- Department of Applied Physics and ‡COMP/Department of Applied Physics, Aalto University School of Science , 00076 Aalto, Finland
| | - Ari Harju
- Department of Applied Physics and ‡COMP/Department of Applied Physics, Aalto University School of Science , 00076 Aalto, Finland
| | - Patrick Rinke
- Department of Applied Physics and ‡COMP/Department of Applied Physics, Aalto University School of Science , 00076 Aalto, Finland
| | - Peter Liljeroth
- Department of Applied Physics and ‡COMP/Department of Applied Physics, Aalto University School of Science , 00076 Aalto, Finland
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45
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Guo Z, Yu P, Sun K, Wang W, Wei Y, Li Z. Two-Dimensional Crystallization of Rylene Diimide Based n-Type Semiconductors Tuned by the Dimensions of the Aromatic Core at the Liquid-Solid Interface. Chem Asian J 2017; 12:1104-1110. [DOI: 10.1002/asia.201700271] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 03/29/2017] [Indexed: 11/11/2022]
Affiliation(s)
- Zongxia Guo
- Key Laboratory of Biobased Polymer Materials, Shandong Provincial Education Department; School of Polymer Science and Engineering; Qingdao University of Science and Technology (QUST); Qingdao 266042 P. R. China
| | - Ping Yu
- Key Laboratory of Biobased Polymer Materials, Shandong Provincial Education Department; School of Polymer Science and Engineering; Qingdao University of Science and Technology (QUST); Qingdao 266042 P. R. China
| | - Kai Sun
- Beijing National Laboratory for Molecular Science (BNLMS); Institute of Chemistry, Chinese Academy of Sciences; Beijing 100190 P. R. China
| | - Wenpin Wang
- Key Laboratory of Biobased Polymer Materials, Shandong Provincial Education Department; School of Polymer Science and Engineering; Qingdao University of Science and Technology (QUST); Qingdao 266042 P. R. China
| | - Yuhan Wei
- Key Laboratory of Biobased Polymer Materials, Shandong Provincial Education Department; School of Polymer Science and Engineering; Qingdao University of Science and Technology (QUST); Qingdao 266042 P. R. China
| | - Zhibo Li
- Key Laboratory of Biobased Polymer Materials, Shandong Provincial Education Department; School of Polymer Science and Engineering; Qingdao University of Science and Technology (QUST); Qingdao 266042 P. R. China
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46
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Folkertsma E, van der Lit J, Di Cicco F, Lutz M, Klein Gebbink RJM, Swart I, Moret ME. Combination of Scanning Probe Microscopy and Coordination Chemistry: Structural and Electronic Study of Bis(methylbenzimidazolyl)ketone and Its Iron Complex. ACS OMEGA 2017; 2:1372-1379. [PMID: 28474011 PMCID: PMC5410654 DOI: 10.1021/acsomega.6b00510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 03/23/2017] [Indexed: 06/07/2023]
Abstract
Here, we report the bulk synthesis of [FeII(BMBIK)Cl2] bearing the redox noninnocent bis(methylbenzimidazolyl)ketone (BMBIK) ligand and the synthesis of the similar complex [FeI(BMBIK)]+ on a Au(111) surface using lateral manipulation at the atomic level. Cyclic voltammetry and scanning tunneling spectroscopy are shown to be useful techniques to compare the coordination compound in solution with the one on the surface. The total charge, as well as the oxidation and spin state of [FeI(BMBIK)]+, are investigated by comparison of the shape of the lowest unoccupied molecular orbital (LUMO), visualized by tunneling through the LUMO, with theoretical models. The similar reduction potentials found for the solution and surface compounds indicate that the major effect of lowering the LUMO upon coordination of BMBIK to the iron center is conserved on the surface. The synthesis and analysis of [FeI(BMBIK)]+ using scanning tunneling microscopy, scanning tunneling spectroscopy, and atomic force microscopy are the first steps toward mechanistic studies of homogeneous catalysts with redox noninnocent ligands at the single molecule level.
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Affiliation(s)
- Emma Folkertsma
- Organic
Chemistry & Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Joost van der Lit
- Condensed
Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University, P.O.
Box 80000, 3508 TA Utrecht, The Netherlands
| | - Francesca Di Cicco
- Condensed
Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University, P.O.
Box 80000, 3508 TA Utrecht, The Netherlands
| | - Martin Lutz
- Crystal
and Structural Chemistry, Bijvoet Center for Biomolecular Research,
Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Robertus J. M. Klein Gebbink
- Organic
Chemistry & Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Ingmar Swart
- Condensed
Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University, P.O.
Box 80000, 3508 TA Utrecht, The Netherlands
| | - Marc-Etienne Moret
- Organic
Chemistry & Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
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47
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Liu ZF, Egger DA, Refaely-Abramson S, Kronik L, Neaton JB. Energy level alignment at molecule-metal interfaces from an optimally tuned range-separated hybrid functional. J Chem Phys 2017. [DOI: 10.1063/1.4975321] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Zhen-Fei Liu
- Molecular Foundry and Materials Sciences Division,
Lawrence Berkeley National Laboratory, Berkeley, California
94720, USA
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - David A. Egger
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovoth 76100, Israel
| | - Sivan Refaely-Abramson
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovoth 76100, Israel
| | - Leeor Kronik
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovoth 76100, Israel
| | - Jeffrey B. Neaton
- Molecular Foundry and Materials Sciences Division,
Lawrence Berkeley National Laboratory, Berkeley, California
94720, USA
- Department of Physics, University of California, Berkeley, California 94720, USA
- Kavli Energy Nanosciences Institute at Berkeley, Berkeley, California 94720, USA
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48
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Vilan A, Aswal D, Cahen D. Large-Area, Ensemble Molecular Electronics: Motivation and Challenges. Chem Rev 2017; 117:4248-4286. [DOI: 10.1021/acs.chemrev.6b00595] [Citation(s) in RCA: 243] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Ayelet Vilan
- Department
of Materials and Interfaces, Weizmann Institute of Science, Rehovot, Israel
| | | | - David Cahen
- Department
of Materials and Interfaces, Weizmann Institute of Science, Rehovot, Israel
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49
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Bouju X, Mattioli C, Franc G, Pujol A, Gourdon A. Bicomponent Supramolecular Architectures at the Vacuum–Solid Interface. Chem Rev 2017; 117:1407-1444. [DOI: 10.1021/acs.chemrev.6b00389] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Xavier Bouju
- CEMES-CNRS, 29 Rue J. Marvig, 31055 Toulouse, France
| | | | - Grégory Franc
- CEMES-CNRS, 29 Rue J. Marvig, 31055 Toulouse, France
| | - Adeline Pujol
- Université de Toulouse, UPS, CNRS, CEMES, 118 route de Narbonne, 31062 Toulouse, France
| | - André Gourdon
- CEMES-CNRS, 29 Rue J. Marvig, 31055 Toulouse, France
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50
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Ajayakumar MR, Alcón I, Bromley ST, Veciana J, Rovira C, Mas-Torrent M. Direct covalent grafting of an organic radical core on gold and silver. RSC Adv 2017. [DOI: 10.1039/c7ra01686g] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A newly designed radical–anchor (R–A) molecule was synthesized and covalently grafted on Ag and Au surface at one atom distance preserving the molecular spin.
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Affiliation(s)
- M. R. Ajayakumar
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC)
- CIBER-BBN
- 08193 Bellaterra
- Spain
| | - I. Alcón
- Departament de Ciència de Materials i Física Química
- Institut de Química Teòrica i Computacional (IQTCUB)
- Universitat de Barcelona
- E-08028 Barcelona
- Spain
| | - S. T. Bromley
- Departament de Ciència de Materials i Física Química
- Institut de Química Teòrica i Computacional (IQTCUB)
- Universitat de Barcelona
- E-08028 Barcelona
- Spain
| | - J. Veciana
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC)
- CIBER-BBN
- 08193 Bellaterra
- Spain
| | - C. Rovira
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC)
- CIBER-BBN
- 08193 Bellaterra
- Spain
| | - M. Mas-Torrent
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC)
- CIBER-BBN
- 08193 Bellaterra
- Spain
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