1
|
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.
Collapse
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
| |
Collapse
|
2
|
Litman Y, Bonafé FP, Akkoush A, Appel H, Rossi M. First-Principles Simulations of Tip Enhanced Raman Scattering Reveal Active Role of Substrate on High-Resolution Images. J Phys Chem Lett 2023; 14:6850-6859. [PMID: 37487223 PMCID: PMC10405274 DOI: 10.1021/acs.jpclett.3c01216] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 07/14/2023] [Indexed: 07/26/2023]
Abstract
Tip-enhanced Raman scattering (TERS) has emerged as a powerful tool to obtain subnanometer spatial resolution fingerprints of atomic motion. Theoretical calculations that can simulate the Raman scattering process and provide an unambiguous interpretation of TERS images often rely on crude approximations of the local electric field. In this work, we present a novel and first-principles-based method to compute TERS images by combining Time Dependent Density Functional Theory (TD-DFT) and Density Functional Perturbation Theory (DFPT) to calculate Raman cross sections with realistic local fields. We present TERS results on free-standing benzene and C60 molecules, and on the TCNE molecule adsorbed on Ag(100). We demonstrate that chemical effects on chemisorbed molecules, often ignored in TERS simulations of larger systems, dramatically change the TERS images. This observation calls for the inclusion of chemical effects for predictive theory-experiment comparisons and an understanding of molecular motion at the nanoscale.
Collapse
Affiliation(s)
- Yair Litman
- Yusuf
Hamied Department of Chemistry, University
of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
- MPI
for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Franco P. Bonafé
- MPI
for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Alaa Akkoush
- MPI
for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
- Fritz
Haber Institute of the Max Planck Society, Faradayweg 4−6, 14195 Berlin, Germany
| | - Heiko Appel
- MPI
for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Mariana Rossi
- MPI
for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
- Fritz
Haber Institute of the Max Planck Society, Faradayweg 4−6, 14195 Berlin, Germany
| |
Collapse
|
3
|
Mier C, Verlhac B, Garnier L, Robles R, Limot L, Lorente N, Choi DJ. Superconducting Scanning Tunneling Microscope Tip to Reveal Sub-millielectronvolt Magnetic Energy Variations on Surfaces. J Phys Chem Lett 2021; 12:2983-2989. [PMID: 33730501 DOI: 10.1021/acs.jpclett.1c00328] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Combining the complex ordering ability of molecules with their local magnetic properties is a little-explored technique to tailor spin structures on surfaces. However, revealing the molecular geometry can be demanding. Nickelocene (Nc) molecules present a large spin-flip excitation leading to clear changes of conductance at the excitation-threshold bias. Using a superconducting tip, we have the energy resolution to detect small shifts of the Nc spin-flip excitation thresholds, permitting us to reveal the different individual environments of Nc molecules in an ordered layer. This knowledge allows us to reveal the adsorption configuration of a complex molecular structure formed by Nc molecules in different orientations and positions. As a consequence, we infer that Nc layers present a strong noncollinear magnetic-moment arrangement.
Collapse
Affiliation(s)
- Cristina Mier
- Centro de Física de Materiales CFM/MPC (CSIC-UPV/EHU), 20018 Donostia-San Sebastián, Spain
| | - Benjamin Verlhac
- Université de Strasbourg CNRS, IPCMS, UMR 7504, F-67000 Strasbourg, France
| | - Léo Garnier
- Université de Strasbourg CNRS, IPCMS, UMR 7504, F-67000 Strasbourg, France
| | - Roberto Robles
- Centro de Física de Materiales CFM/MPC (CSIC-UPV/EHU), 20018 Donostia-San Sebastián, Spain
| | - Laurent Limot
- Université de Strasbourg CNRS, IPCMS, UMR 7504, F-67000 Strasbourg, France
| | - Nicolás Lorente
- Centro de Física de Materiales CFM/MPC (CSIC-UPV/EHU), 20018 Donostia-San Sebastián, Spain
- Donostia International Physics Center (DIPC), 20018 Donostia-San Sebastián, Spain
| | - Deung-Jang Choi
- Centro de Física de Materiales CFM/MPC (CSIC-UPV/EHU), 20018 Donostia-San Sebastián, Spain
- Donostia International Physics Center (DIPC), 20018 Donostia-San Sebastián, Spain
- Ikerbasque, Basque Foundation for Science, 48013 Bilbao, Spain
| |
Collapse
|
4
|
Stoll P, Lotze C, Ladenthin JN, Umbach TR, Fernández-Torrente I, Franke KJ. Correlation of Kondo effect and molecular conformation of the acceptor molecule in the TTF-TCNE charge transfer complex. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:454002. [PMID: 30265245 DOI: 10.1088/1361-648x/aae502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A Kondo resonance has been observed on purely organic molecules in several combinations of charge transfer complexes on a metal surface. It has been regarded as a fingerprint of the transfer of one electron from the donor to the extended π orbital of the acceptor's LUMO. Here, we investigate the stoichiometric checkerboard structure of tetrathiafulvalene (TTF) and tetracyanoethylene (TCNE) on a Au(1 1 1) surface using scanning tunneling and atomic force microscopy at 4.8 K. We find a bistable state of the TCNE molecules with distinct structural and electronic properties. The two states represent different conformations of the TCNE within the structure. One of them exhibits a Kondo resonance, whereas the other one does not, despite of both TCNE types being singly charged.
Collapse
Affiliation(s)
- Paul Stoll
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
| | | | | | | | | | | |
Collapse
|
5
|
Obersteiner V, Scherbela M, Hörmann L, Wegner D, Hofmann OT. Structure Prediction for Surface-Induced Phases of Organic Monolayers: Overcoming the Combinatorial Bottleneck. NANO LETTERS 2017; 17:4453-4460. [PMID: 28640634 PMCID: PMC5512157 DOI: 10.1021/acs.nanolett.7b01637] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 06/17/2017] [Indexed: 05/24/2023]
Abstract
Structure determination and prediction pose a major challenge to computational material science, demanding efficient global structure search techniques tailored to identify promising and relevant candidates. A major bottleneck is the fact that due to the many combinatorial possibilities, there are too many possible geometries to be sampled exhaustively. Here, an innovative computational approach to overcome this problem is presented that explores the potential energy landscape of commensurate organic/inorganic interfaces where the orientation and conformation of the molecules in the tightly packed layer is close to a favorable geometry adopted by isolated molecules on the surface. It is specifically designed to sample the energetically lowest lying structures, including the thermodynamic minimum, in order to survey the particularly rich and intricate polymorphism in such systems. The approach combines a systematic discretization of the configuration space, which leads to a huge reduction of the combinatorial possibilities with an efficient exploration of the potential energy surface inspired by the Basin-Hopping method. Interfacing the algorithm with first-principles calculations, the power and efficiency of this approach is demonstrated for the example of the organic molecule TCNE (tetracyanoethylene) on Au(111). For the pristine metal surface, the global minimum structure is found to be at variance with the geometry found by scanning tunneling microscopy. Rather, our results suggest the presence of surface adatoms or vacancies that are not imaged in the experiment.
Collapse
Affiliation(s)
- Veronika Obersteiner
- Institute of Solid
State Physics, NAWI Graz, Graz University
of Technology, Petersgasse
16, 8010 Graz, Austria
| | - Michael Scherbela
- Institute of Solid
State Physics, NAWI Graz, Graz University
of Technology, Petersgasse
16, 8010 Graz, Austria
| | - Lukas Hörmann
- Institute of Solid
State Physics, NAWI Graz, Graz University
of Technology, Petersgasse
16, 8010 Graz, Austria
| | - Daniel Wegner
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Oliver T. Hofmann
- Institute of Solid
State Physics, NAWI Graz, Graz University
of Technology, Petersgasse
16, 8010 Graz, Austria
| |
Collapse
|
6
|
Rodríguez-Fernández J, Lauwaet K, Herranz MÁ, Martín N, Gallego JM, Miranda R, Otero R. Temperature-controlled metal/ligand stoichiometric ratio in Ag-TCNE coordination networks. J Chem Phys 2015; 142:101930. [PMID: 25770519 DOI: 10.1063/1.4913326] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The deposition of tetracyanoethylene (TCNE) on Ag(111), both at Room Temperature (RT, 300 K) and low temperatures (150 K), leads to the formation of coordination networks involving silver adatoms, as revealed by Variable-Temperature Scanning Tunneling Microscopy. Our results indicate that TCNE molecules etch away material from the step edges and possibly also from the terraces, which facilitates the formation of the observed coordination networks. Moreover, such process is temperature dependent, which allows for different stoichiometric ratios between Ag and TCNE just by adjusting the deposition temperature. X-ray Photoelectron Spectroscopy and Density Functional Theory calculations reveal that charge-transfer from the surface to the molecule and the concomitant geometrical distortions at both sides of the organic/inorganic interface might facilitate the extraction of silver atoms from the step-edges and, thus, its incorporation into the observed TCNE coordination networks.
Collapse
Affiliation(s)
- Jonathan Rodríguez-Fernández
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
| | - Koen Lauwaet
- IMDEA Nanoscience, c∖Faraday 9, Campus de Cantoblanco, 28049 Madrid, Spain
| | - Maria Ángeles Herranz
- Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Ciudad Universitaria s/n, Madrid, Spain
| | - Nazario Martín
- IMDEA Nanoscience, c∖Faraday 9, Campus de Cantoblanco, 28049 Madrid, Spain
| | - José María Gallego
- IMDEA Nanoscience, c∖Faraday 9, Campus de Cantoblanco, 28049 Madrid, Spain
| | - Rodolfo Miranda
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
| | - Roberto Otero
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
| |
Collapse
|
7
|
Wagner C, Fournier N, Tautz FS, Temirov R. The role of surface corrugation and tip oscillation in single-molecule manipulation with a non-contact atomic force microscope. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2014; 5:202-9. [PMID: 24605287 PMCID: PMC3943512 DOI: 10.3762/bjnano.5.22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 01/31/2014] [Indexed: 05/05/2023]
Abstract
Scanning probe microscopy (SPM) plays an important role in the investigation of molecular adsorption. The possibility to probe the molecule-surface interaction while tuning its strength through SPM tip-induced single-molecule manipulation has particularly promising potential to yield new insights. We recently reported experiments, in which 3,4,9,10-perylene-tetracarboxylic-dianhydride (PTCDA) molecules were lifted with a qPlus-sensor and analyzed these experiments by using force-field simulations. Irrespective of the good agreement between the experiment and those simulations, systematic inconsistencies remained that we attribute to effects omitted from the initial model. Here we develop a more realistic simulation of single-molecule manipulation by non-contact AFM that includes the atomic surface corrugation, the tip elasticity, and the tip oscillation amplitude. In short, we simulate a full tip oscillation cycle at each step of the manipulation process and calculate the frequency shift by solving the equation of motion of the tip. The new model correctly reproduces previously unexplained key features of the experiment, and facilitates a better understanding of the mechanics of single-molecular junctions. Our simulations reveal that the surface corrugation adds a positive frequency shift to the measurement that generates an apparent repulsive force. Furthermore, we demonstrate that the scatter observed in the experimental data points is related to the sliding of the molecule across the surface.
Collapse
Affiliation(s)
- Christian Wagner
- Leiden Institute of Physics, Universiteit Leiden, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands
- Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, 52425 Jülich, Germany
- Jülich Aachen Research Alliance (JARA)-Fundamentals of Future Information Technology, 52425 Jülich, Germany
| | - Norman Fournier
- Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, 52425 Jülich, Germany
- Jülich Aachen Research Alliance (JARA)-Fundamentals of Future Information Technology, 52425 Jülich, Germany
| | - F Stefan Tautz
- Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, 52425 Jülich, Germany
- Jülich Aachen Research Alliance (JARA)-Fundamentals of Future Information Technology, 52425 Jülich, Germany
| | - Ruslan Temirov
- Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, 52425 Jülich, Germany
- Jülich Aachen Research Alliance (JARA)-Fundamentals of Future Information Technology, 52425 Jülich, Germany
| |
Collapse
|
8
|
Schuler B, Liu W, Tkatchenko A, Moll N, Meyer G, Mistry A, Fox D, Gross L. Adsorption geometry determination of single molecules by atomic force microscopy. PHYSICAL REVIEW LETTERS 2013; 111:106103. [PMID: 25166684 DOI: 10.1103/physrevlett.111.106103] [Citation(s) in RCA: 106] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Indexed: 05/22/2023]
Abstract
We measured the adsorption geometry of single molecules with intramolecular resolution using noncontact atomic force microscopy with functionalized tips. The lateral adsorption position was determined with atomic resolution, adsorption height differences with a precision of 3 pm, and tilts of the molecular plane within 0.2°. The method was applied to five π-conjugated molecules, including three molecules from the olympicene family, adsorbed on Cu(111). For the olympicenes, we found that the substitution of a single atom leads to strong variations of the adsorption height, as predicted by state-of-the-art density-functional theory, including van der Waals interactions with collective substrate response effects.
Collapse
Affiliation(s)
- Bruno Schuler
- IBM Research-Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - Wei Liu
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - Alexandre Tkatchenko
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - Nikolaj Moll
- IBM Research-Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - Gerhard Meyer
- IBM Research-Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - Anish Mistry
- University of Warwick, Gibbet Hill, CV34 Warwick, United Kingdom
| | - David Fox
- University of Warwick, Gibbet Hill, CV34 Warwick, United Kingdom
| | - Leo Gross
- IBM Research-Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| |
Collapse
|
9
|
Burema SR, Bocquet ML. A sum rule for inelastic electron tunneling spectroscopy: an ab initio study of a donor (TTF) and acceptors (TCNE, TCNQ and DCNQI) parallelly oriented on Cu(100). Phys Chem Chem Phys 2013; 15:16111-9. [DOI: 10.1039/c3cp53049c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
|