1
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Salthouse R, Hurtado-Gallego J, Grace IM, Davidson R, Alshammari O, Agraït N, Lambert CJ, Bryce MR. Electronic Conductance and Thermopower of Cross-Conjugated and Skipped-Conjugated Molecules in Single-Molecule Junctions. J Phys Chem C Nanomater Interfaces 2023; 127:13751-13758. [PMID: 37528901 PMCID: PMC10389811 DOI: 10.1021/acs.jpcc.3c00742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 06/21/2023] [Indexed: 08/03/2023]
Abstract
We report a combined experimental and theoretical study of a series of thiomethyl (SMe) anchored cross-conjugated molecules featuring an acyclic central bridging ketone and their analogous skipped-conjugated alcohol derivatives. Studies of these molecules in a gold|single-molecule|gold junction using scanning tunneling microscopy-break junction techniques reveal a similar conductance (G) value for both the cross-conjugated molecules and their skipped-conjugated partners. Theoretical studies based on density functional theory of the molecules in their optimum geometries in the junction reveal the reason for this similarity in conductance, as the predicted conductance for the alcohol series of compounds varies more with the tilt angle. Thermopower measurements reveal a higher Seebeck coefficient (S) for the cross-conjugated ketone molecules relative to the alcohol derivatives, with a particularly high S for the biphenyl derivative 3a (-15.6 μV/K), an increase of threefold compared to its alcohol analog. The predicted behavior of the quantum interference (QI) in this series of cross-conjugated molecules is found to be constructive, though the appearance of a destructive QI feature for 3a is due to the degeneracy of the HOMO orbital and may explain the enhancement of the value of S for this molecule.
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Affiliation(s)
| | - Juan Hurtado-Gallego
- Departamento
de Física de la Materia Condensada, Universidad Autónoma de Madrid, Madrid E-28049, Spain
| | - Iain M. Grace
- Physics
Department, Lancaster University, Lancaster LA1 4YB, U.K.
| | - Ross Davidson
- Department
of Chemistry, Durham University, Durham DH1 3LE, U.K.
| | - Ohud Alshammari
- Physics
Department, Lancaster University, Lancaster LA1 4YB, U.K.
| | - Nicolás Agraït
- Departamento
de Física de la Materia Condensada, Universidad Autónoma de Madrid, Madrid E-28049, Spain
- Condensed
Matter Physics Center (IFIMAC) and Instituto Universitatio de Ciencia
de Materiales “Nicolás Cabrera” (INC), Universidad Autónoma de Madrid, Madrid E-28049, Spain
- Instituto
Madrileño de Estudios Avanzados en Nanociencia IMDEA-Nanociencia, Madrid E-28049, Spain
| | - Colin J. Lambert
- Physics
Department, Lancaster University, Lancaster LA1 4YB, U.K.
| | - Martin R. Bryce
- Department
of Chemistry, Durham University, Durham DH1 3LE, U.K.
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2
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Svatek S, Sacchetti V, Rodríguez-Pérez L, Illescas BM, Rincón-García L, Rubio-Bollinger G, González MT, Bailey S, Lambert CJ, Martín N, Agraït N. Enhanced Thermoelectricity in Metal-[60]Fullerene-Graphene Molecular Junctions. Nano Lett 2023; 23:2726-2732. [PMID: 36970777 PMCID: PMC10103166 DOI: 10.1021/acs.nanolett.3c00014] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 03/14/2023] [Indexed: 06/18/2023]
Abstract
The thermoelectric properties of molecular junctions consisting of a metal Pt electrode contacting [60]fullerene derivatives covalently bound to a graphene electrode have been studied by using a conducting-probe atomic force microscope (c-AFM). The [60]fullerene derivatives are covalently linked to the graphene via two meta-connected phenyl rings, two para-connected phenyl rings, or a single phenyl ring. We find that the magnitude of the Seebeck coefficient is up to nine times larger than that of Au-C60-Pt molecular junctions. Moreover, the sign of the thermopower can be either positive or negative depending on the details of the binding geometry and on the local value of the Fermi energy. Our results demonstrate the potential of using graphene electrodes for controlling and enhancing the thermoelectric properties of molecular junctions and confirm the outstanding performance of [60]fullerene derivatives.
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Affiliation(s)
- Simon
A. Svatek
- Instituto
Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Faraday 9, Ciudad Universitaria
de Cantoblanco, 28049 Madrid, Spain
- Departamento
de Física de la Materia Condensada, Facultad de Ciencias, Universidad Autónoma de Madrid, C/Francisco Tomás y Valiente
7, 28049 Madrid, Spain
| | - Valentina Sacchetti
- Instituto
Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Faraday 9, Ciudad Universitaria
de Cantoblanco, 28049 Madrid, Spain
- Organic
Chemistry Department, Faculty of Chemistry, Universidad Complutense de Madrid, E-28040 Madrid, Spain
| | - Laura Rodríguez-Pérez
- Organic
Chemistry Department, Faculty of Chemistry, Universidad Complutense de Madrid, E-28040 Madrid, Spain
| | - Beatriz M. Illescas
- Organic
Chemistry Department, Faculty of Chemistry, Universidad Complutense de Madrid, E-28040 Madrid, Spain
| | - Laura Rincón-García
- Departamento
de Física de la Materia Condensada, Facultad de Ciencias, Universidad Autónoma de Madrid, C/Francisco Tomás y Valiente
7, 28049 Madrid, Spain
| | - Gabino Rubio-Bollinger
- Departamento
de Física de la Materia Condensada, Facultad de Ciencias, Universidad Autónoma de Madrid, C/Francisco Tomás y Valiente
7, 28049 Madrid, Spain
- Condensed
Matter Physics Center (IFIMAC) and Instituto Universitario de Ciencia
de Materiales “Nicolás Cabrera” (INC), Facultad
de Ciencias, Universidad Autónoma
de Madrid, C/Francisco
Tomás y Valiente 7, 28049 Madrid, Spain
| | - M. Teresa González
- Instituto
Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Faraday 9, Ciudad Universitaria
de Cantoblanco, 28049 Madrid, Spain
| | - Steven Bailey
- Department
of Physics, Lancaster University, Lancaster LA1 4YW, United Kingdom
| | - Colin J. Lambert
- Department
of Physics, Lancaster University, Lancaster LA1 4YW, United Kingdom
| | - Nazario Martín
- Instituto
Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Faraday 9, Ciudad Universitaria
de Cantoblanco, 28049 Madrid, Spain
- Organic
Chemistry Department, Faculty of Chemistry, Universidad Complutense de Madrid, E-28040 Madrid, Spain
| | - Nicolás Agraït
- Instituto
Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Faraday 9, Ciudad Universitaria
de Cantoblanco, 28049 Madrid, Spain
- Departamento
de Física de la Materia Condensada, Facultad de Ciencias, Universidad Autónoma de Madrid, C/Francisco Tomás y Valiente
7, 28049 Madrid, Spain
- Condensed
Matter Physics Center (IFIMAC) and Instituto Universitario de Ciencia
de Materiales “Nicolás Cabrera” (INC), Facultad
de Ciencias, Universidad Autónoma
de Madrid, C/Francisco
Tomás y Valiente 7, 28049 Madrid, Spain
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3
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Daaoub A, Ornago L, Vogel D, Bastante P, Sangtarash S, Parmeggiani M, Kamer J, Agraït N, Mayor M, van der Zant H, Sadeghi H. Engineering Transport Orbitals in Single-Molecule Junctions. J Phys Chem Lett 2022; 13:9156-9164. [PMID: 36166407 PMCID: PMC9549519 DOI: 10.1021/acs.jpclett.2c01851] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 09/22/2022] [Indexed: 05/25/2023]
Abstract
Controlling charge transport through molecules is challenging because it requires engineering of the energy of molecular orbitals involved in the transport process. While side groups are central to maintaining solubility in many molecular materials, their role in modulating charge transport through single-molecule junctions has received less attention. Here, using two break-junction techniques and computational modeling, we investigate systematically the effect of electron-donating and -withdrawing side groups on the charge transport through single molecules. By characterizing the conductance and thermopower, we demonstrate that side groups can be used to manipulate energy levels of the transport orbitals. Furthermore, we develop a novel statistical approach to model quantum transport through molecular junctions. The proposed method does not treat the electrodes' chemical potential as a free parameter and leads to more robust prediction of electrical conductance as confirmed by our experiment. The new method is generic and can be used to predict the conductance of molecules.
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Affiliation(s)
- Abdalghani Daaoub
- School
of Engineering, University of Warwick, CV4 7AL Coventry, United Kingdom
| | - Luca Ornago
- Kavli
Institute of Nanoscience, Delft University
of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - David Vogel
- Department
of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
| | - Pablo Bastante
- Departamento
de Física de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Sara Sangtarash
- School
of Engineering, University of Warwick, CV4 7AL Coventry, United Kingdom
| | - Matteo Parmeggiani
- Department
of Applied Science and Technology (DISAT), Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy
| | - Jerry Kamer
- Kavli
Institute of Nanoscience, Delft University
of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Nicolás Agraït
- Departamento
de Física de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Marcel Mayor
- Department
of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
- Institute
for Nanotechnology, Karlsruhe Institute
of Technology (KIT), P.O. Box 3640, 76021 Karlsruhe, Germany
- Lehn
Institute of Functional Materials (LIFM), School of Chemistry, Sun Yat-Sen University (SYSU), 510275 Guangzhou, China
| | - Herre van der Zant
- Kavli
Institute of Nanoscience, Delft University
of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Hatef Sadeghi
- School
of Engineering, University of Warwick, CV4 7AL Coventry, United Kingdom
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4
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Rincón-García L, Thompson D, Mittapally R, Agraït N, Meyhofer E, Reddy P. Enhancement and Saturation of Near-Field Radiative Heat Transfer in Nanogaps between Metallic Surfaces. Phys Rev Lett 2022; 129:145901. [PMID: 36240403 DOI: 10.1103/physrevlett.129.145901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 05/27/2022] [Accepted: 09/08/2022] [Indexed: 06/16/2023]
Abstract
Near-field radiative heat transfer (NFRHT) between planar metallic surfaces was computationally explored over five decades ago by Polder and van Hove [Phys. Rev. B 4, 3303 (1971)PLRBAQ0556-280510.1103/PhysRevB.4.3303]. These studies predicted that, as the gap size (d) between the surfaces decreased, the radiative heat flux first increases by several orders of magnitude until d is ∼100 nm after which the heat flux saturates. However, despite both the fundamental and practical importance of these predictions, the combined enhancement and saturation of NFRHT at small gaps in metallic surfaces remains experimentally unverified. Here, we probe NFRHT between planar metallic (Pt, Au) surfaces and show that RHT rates can exceed the far-field rate by over a thousand times when d is reduced to ∼25 nm. More importantly, we show that for small values of d RHT saturates due to the dominant contributions from transverse electric evanescent modes. Our results are in excellent agreement with the predictions of fluctuational electrodynamics and are expected to inform the development of technologies such as near-field thermophotovoltaics, radiative heat-assisted magnetic recording, and nanolithography.
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Affiliation(s)
- Laura Rincón-García
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Dakotah Thompson
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Rohith Mittapally
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Nicolás Agraït
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), C/Faraday 9, E-28049 Madrid, Spain
- Condensed Matter Physics Center (IFIMAC) and Instituto Universitario de Ciencia de Materiales "Nicolás Cabrera" (INC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Edgar Meyhofer
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Pramod Reddy
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
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5
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Roemer M, Gillespie A, Jago D, Costa-Milan D, Alqahtani J, Hurtado-Gallego J, Sadeghi H, Lambert CJ, Spackman PR, Sobolev AN, Skelton BW, Grosjean A, Walkey M, Kampmann S, Vezzoli A, Simpson PV, Massi M, Planje I, Rubio-Bollinger G, Agraït N, Higgins SJ, Sangtarash S, Piggott MJ, Nichols RJ, Koutsantonis GA. 2,7- and 4,9-Dialkynyldihydropyrene Molecular Switches: Syntheses, Properties, and Charge Transport in Single-Molecule Junctions. J Am Chem Soc 2022; 144:12698-12714. [PMID: 35767015 DOI: 10.1021/jacs.2c02289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This paper describes the syntheses of several functionalized dihydropyrene (DHP) molecular switches with different substitution patterns. Regioselective nucleophilic alkylation of a 5-substituted dimethyl isophthalate allowed the development of a workable synthetic protocol for the preparation of 2,7-alkyne-functionalized DHPs. Synthesis of DHPs with surface-anchoring groups in the 2,7- and 4,9-positions is described. The molecular structures of several intermediates and DHPs were elucidated by X-ray single-crystal diffraction. Molecular properties and switching capabilities of both types of DHPs were assessed by light irradiation experiments, spectroelectrochemistry, and cyclic voltammetry. Spectroelectrochemistry, in combination with density functional theory (DFT) calculations, shows reversible electrochemical switching from the DHP forms to the cyclophanediene (CPD) forms. Charge-transport behavior was assessed in single-molecule scanning tunneling microscope (STM) break junctions, combined with density functional theory-based quantum transport calculations. All DHPs with surface-contacting groups form stable molecular junctions. Experiments show that the molecular conductance depends on the substitution pattern of the DHP motif. The conductance was found to decrease with increasing applied bias.
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Affiliation(s)
- Max Roemer
- Chemistry, School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Angus Gillespie
- Chemistry, School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - David Jago
- Chemistry, School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - David Costa-Milan
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, United Kingdom
| | - Jehan Alqahtani
- Department of Physics, King Khalid University, Abha 62529, Saudi Arabia
- Department of Physics, Lancaster University, Lancaster LA1 4YB, United Kingdom
| | - Juan Hurtado-Gallego
- Condensed Matter Physics Center (IFIMAC) and Instituto Universitatio de Ciencia de Materiales "Nicolás Cabrera" (INC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Hatef Sadeghi
- School of Engineering, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Colin J Lambert
- Department of Physics, Lancaster University, Lancaster LA1 4YB, United Kingdom
| | - Peter R Spackman
- Chemistry, School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Alexandre N Sobolev
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Crawley, WA 6009, Australia
| | - Brian W Skelton
- Chemistry, School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Crawley, WA 6009, Australia
| | - Arnaud Grosjean
- Chemistry, School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Mark Walkey
- Chemistry, School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Sven Kampmann
- Chemistry, School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Andrea Vezzoli
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, United Kingdom
| | - Peter V Simpson
- School of Molecular and Life Sciences, Curtin University, Perth, WA 6102, Australia
| | - Massimiliano Massi
- School of Molecular and Life Sciences, Curtin University, Perth, WA 6102, Australia
| | - Inco Planje
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, United Kingdom
| | - Gabino Rubio-Bollinger
- Condensed Matter Physics Center (IFIMAC) and Instituto Universitatio de Ciencia de Materiales "Nicolás Cabrera" (INC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Nicolás Agraït
- Condensed Matter Physics Center (IFIMAC) and Instituto Universitatio de Ciencia de Materiales "Nicolás Cabrera" (INC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia IMDEA-Nanociencia, E-28049 Madrid, Spain
| | - Simon J Higgins
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, United Kingdom
| | - Sara Sangtarash
- School of Engineering, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Matthew J Piggott
- Chemistry, School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Richard J Nichols
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, United Kingdom
| | - George A Koutsantonis
- Chemistry, School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
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6
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Ismael AK, Rincón-García L, Evangeli C, Dallas P, Alotaibi T, Al-Jobory AA, Rubio-Bollinger G, Porfyrakis K, Agraït N, Lambert CJ. Exploring seebeck-coefficient fluctuations in endohedral-fullerene, single-molecule junctions. Nanoscale Horiz 2022; 7:616-625. [PMID: 35439804 DOI: 10.1039/d1nh00527h] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
For the purpose of creating single-molecule junctions, which can convert a temperature difference ΔT into a voltage ΔV via the Seebeck effect, it is of interest to screen molecules for their potential to deliver high values of the Seebeck coefficient S = -ΔV/ΔT. Here we demonstrate that insight into molecular-scale thermoelectricity can be obtained by examining the widths and extreme values of Seebeck histograms. Using a combination of experimental scanning-tunnelling-microscopy-based transport measurements and density-functional-theory-based transport calculations, we study the electrical conductance and Seebeck coefficient of three endohedral metallofullerenes (EMFs) Sc3N@C80, Sc3C2@C80, and Er3N@C80, which based on their structures, are selected to exhibit different degrees of charge inhomogeneity and geometrical disorder within a junction. We demonstrate that standard deviations in the Seebeck coefficient σS of EMF-based junctions are correlated with the geometric standard deviation σ and the charge inhomogeneity σq. We benchmark these molecules against C60 and demonstrate that both σq, σS are the largest for Sc3C2@C80, both are the smallest for C60 and for the other EMFs, they follow the order Sc3C2@C80 > Sc3N@C80 > Er3N@C80 > C60. A large value of σS is a sign that a molecule can exhibit a wide range of Seebeck coefficients, which means that if orientations corresponding to high values can be selected and controlled, then the molecule has the potential to exhibit high-performance thermoelectricity. For the EMFs studied here, large values of σS are associated with distributions of Seebeck coefficients containing both positive and negative signs, which reveals that all these EMFs are bi-thermoelectric materials.
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Affiliation(s)
- Ali K Ismael
- Department of Physics, Lancaster University, Lancaster, UK.
- Department of Physics, College of Education for Pure Science, Tikrit University, Tikrit, Iraq
| | - Laura Rincón-García
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | | | - Panagiotis Dallas
- Institute of Nanoscience and Nanotechnology, NCSR Demokritos, 15310 Athens, Greece
- Department of Materials, University of Oxford, OX1 3PH, UK
| | - Turki Alotaibi
- Department of Physics, Lancaster University, Lancaster, UK.
- Department of Physics, College of Science, Jouf University, Sakaka, Saudi Arabia
| | - Alaa A Al-Jobory
- Department of Physics, Lancaster University, Lancaster, UK.
- Department of Physics, College of Science, University of Anbar, Anbar, Iraq
| | - Gabino Rubio-Bollinger
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Condensed Matter Physics Center (IFIMAC) and Instituto Universitario de Ciencia de Materiales "Nicolás Cabrera" (INC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Kyriakos Porfyrakis
- Department of Materials, University of Oxford, OX1 3PH, UK
- Faculty of Engineering and Science, University of Greenwich, Central Avenue, Chatham Maritime, ME4 4TB, UK
| | - Nicolás Agraït
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Condensed Matter Physics Center (IFIMAC) and Instituto Universitario de Ciencia de Materiales "Nicolás Cabrera" (INC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Fundación IMDEA Nanociencia, Calle Faraday 9, Campus Universitario de Cantoblanco, E-28049 Madrid, Spain
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7
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Hurtado-Gallego J, Sangtarash S, Davidson R, Rincón-García L, Daaoub A, Rubio-Bollinger G, Lambert CJ, Oganesyan VS, Bryce MR, Agraït N, Sadeghi H. Thermoelectric Enhancement in Single Organic Radical Molecules. Nano Lett 2022; 22:948-953. [PMID: 35073099 DOI: 10.1021/acs.nanolett.1c03698] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Organic thermoelectric materials have potential for wearable heating, cooling, and energy generation devices at room temperature. For this to be technologically viable, high-conductance (G) and high-Seebeck-coefficient (S) materials are needed. For most semiconductors, the increase in S is accompanied by a decrease in G. Here, using a combined experimental and theoretical investigation, we demonstrate that a simultaneous enhancement of S and G can be achieved in single organic radical molecules, thanks to their intrinsic spin state. A counterintuitive quantum interference (QI) effect is also observed in stable Blatter radical molecules, where constructive QI occurs for a meta-connected radical, leading to further enhancement of thermoelectric properties. Compared to an analogous closed-shell molecule, the power factor is enhanced by more than 1 order of magnitude in radicals. These results open a new avenue for the development of organic thermoelectric materials operating at room temperature.
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Affiliation(s)
- Juan Hurtado-Gallego
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Sara Sangtarash
- Device Modelling Group, School of Engineering, University of Warwick, CV4 7AL Coventry, United Kingdom
| | - Ross Davidson
- Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
| | - Laura Rincón-García
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Abdalghani Daaoub
- Device Modelling Group, School of Engineering, University of Warwick, CV4 7AL Coventry, United Kingdom
| | - Gabino Rubio-Bollinger
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Condensed Matter Physics Center (IFIMAC) and Instituto Universitatio de Ciencia de Materiales "Nicolás Cabrera" (INC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Colin J Lambert
- Physics Department, Lancaster University, Lancaster LA1 4YB, United Kingdom
| | - Vasily S Oganesyan
- School of Chemistry, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Martin R Bryce
- Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
| | - Nicolás Agraït
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Condensed Matter Physics Center (IFIMAC) and Instituto Universitatio de Ciencia de Materiales "Nicolás Cabrera" (INC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia IMDEA-Nanociencia, E-28049 Madrid, Spain
| | - Hatef Sadeghi
- Device Modelling Group, School of Engineering, University of Warwick, CV4 7AL Coventry, United Kingdom
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8
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Xu W, Leary E, Sangtarash S, Jirasek M, González MT, Christensen KE, Abellán Vicente L, Agraït N, Higgins SJ, Nichols RJ, Lambert CJ, Anderson HL. A Peierls Transition in Long Polymethine Molecular Wires: Evolution of Molecular Geometry and Single-Molecule Conductance. J Am Chem Soc 2021; 143:20472-20481. [PMID: 34817985 DOI: 10.1021/jacs.1c10747] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Molecules capable of mediating charge transport over several nanometers with minimal decay in conductance have fundamental and technological implications. Polymethine cyanine dyes are fascinating molecular wires because up to a critical length, they have no bond-length alternation (BLA) and their electronic structure resembles a one-dimensional free-electron gas. Beyond this threshold, they undergo a symmetry-breaking Peierls transition, which increases the HOMO-LUMO gap. We have investigated cationic cyanines with central polymethine chains of 5-13 carbon atoms (Cy3+-Cy11+). The absorption spectra and crystal structures show that symmetry breaking is sensitive to the polarity of the medium and the size of the counterion. X-ray crystallography reveals that Cy9·PF6 and Cy11·B(C6F5)4 are Peierls distorted, with high BLA at one end of the π-system, away from the partially delocalized positive charge. This pattern of BLA distribution resembles that of solitons in polyacetylene. The single-molecule conductance is essentially independent of molecular length for the polymethine salts of Cy3+-Cy11+ with the large B(C6F5)4- counterion, but with the PF6- counterion, the conductance decreases for the longer molecules, Cy7+-Cy11+, because this smaller anion polarizes the π-system, inducing a symmetry-breaking transition. At higher bias (0.9 V), the conductance of the shorter chains, Cy3+-Cy7+, increases with length (negative attenuation factor, β = -1.6 nm-1), but the conductance still drops in Cy9+ and Cy11+ with the small polarizing PF6- counteranion.
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Affiliation(s)
- Wenjun Xu
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - Edmund Leary
- Fundación IMDEA Nanociencia, Calle Faraday 9, Campus Universitario de Cantoblanco, 28049 Madrid, Spain
| | - Sara Sangtarash
- School of Engineering, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Michael Jirasek
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - M Teresa González
- Fundación IMDEA Nanociencia, Calle Faraday 9, Campus Universitario de Cantoblanco, 28049 Madrid, Spain
| | - Kirsten E Christensen
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - Lydia Abellán Vicente
- Fundación IMDEA Nanociencia, Calle Faraday 9, Campus Universitario de Cantoblanco, 28049 Madrid, Spain
| | - Nicolás Agraït
- Fundación IMDEA Nanociencia, Calle Faraday 9, Campus Universitario de Cantoblanco, 28049 Madrid, Spain.,Departamento de Física de la Materia Condensada, IFIMAC and Instituto "Nicolás Cabrera", Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Simon J Higgins
- Department of Chemistry, Donnan and Robert Robinson Laboratories, University of Liverpool, Liverpool L69 7ZD, United Kingdom
| | - Richard J Nichols
- Department of Chemistry, Donnan and Robert Robinson Laboratories, University of Liverpool, Liverpool L69 7ZD, United Kingdom
| | - Colin J Lambert
- Department of Physics, Lancaster University, Lancaster LA1 4YW, United Kingdom
| | - Harry L Anderson
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford OX1 3TA, United Kingdom
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9
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Xu W, Leary E, Hou S, Sangtarash S, González MT, Rubio‐Bollinger G, Wu Q, Sadeghi H, Tejerina L, Christensen KE, Agraït N, Higgins SJ, Lambert CJ, Nichols RJ, Anderson HL. Berichtigung: Unusual Length Dependence of the Conductance in Cumulene Molecular Wires. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202102667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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10
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Xu W, Leary E, Hou S, Sangtarash S, González MT, Rubio-Bollinger G, Wu Q, Sadeghi H, Tejerina L, Christensen KE, Agraït N, Higgins SJ, Lambert CJ, Nichols RJ, Anderson HL. Corrigendum: Unusual Length Dependence of the Conductance in Cumulene Molecular Wires. Angew Chem Int Ed Engl 2021; 60:9170. [PMID: 33844403 PMCID: PMC8173639 DOI: 10.1002/anie.202102667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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11
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Naher M, Milan DC, Al-Owaedi OA, Planje IJ, Bock S, Hurtado-Gallego J, Bastante P, Abd Dawood ZM, Rincón-García L, Rubio-Bollinger G, Higgins SJ, Agraït N, Lambert CJ, Nichols RJ, Low PJ. Molecular Structure-(Thermo)electric Property Relationships in Single-Molecule Junctions and Comparisons with Single- and Multiple-Parameter Models. J Am Chem Soc 2021; 143:3817-3829. [PMID: 33606524 DOI: 10.1021/jacs.0c11605] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The most probable single-molecule conductance of each member of a series of 12 conjugated molecular wires, 6 of which contain either a ruthenium or platinum center centrally placed within the backbone, has been determined. The measurement of a small, positive Seebeck coefficient has established that transmission through these molecules takes place by tunneling through the tail of the HOMO resonance near the middle of the HOMO-LUMO gap in each case. Despite the general similarities in the molecular lengths and frontier-orbital compositions, experimental and computationally determined trends in molecular conductance values across this series cannot be satisfactorily explained in terms of commonly discussed "single-parameter" models of junction conductance. Rather, the trends in molecular conductance are better rationalized from consideration of the complete molecular junction, with conductance values well described by transport calculations carried out at the DFT level of theory, on the basis of the Landauer-Büttiker model.
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Affiliation(s)
- Masnun Naher
- School of Molecular Sciences, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
| | - David C Milan
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, U.K
| | - Oday A Al-Owaedi
- Department of Laser Physics, College of Science for Girls, The University of Babylon, Hilla 51001, Iraq
| | - Inco J Planje
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, U.K
| | - Sören Bock
- School of Molecular Sciences, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
| | - Juan Hurtado-Gallego
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Madrid E-28049, Spain
| | - Pablo Bastante
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Madrid E-28049, Spain
| | - Zahra Murtada Abd Dawood
- Department of Laser Physics, College of Science for Girls, The University of Babylon, Hilla 51001, Iraq
| | - Laura Rincón-García
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Madrid E-28049, Spain
| | - Gabino Rubio-Bollinger
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Madrid E-28049, Spain.,Condensed Matter Physics Center (IFIMAC) and Instituto Universitario de Ciencia de Materiales "Nicolás Cabrera" (INC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Simon J Higgins
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, U.K
| | - Nicolás Agraït
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Madrid E-28049, Spain.,Condensed Matter Physics Center (IFIMAC) and Instituto Universitario de Ciencia de Materiales "Nicolás Cabrera" (INC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain.,Instituto Madrileño de Estudios Avanzados en Nanociencia IMDEA-Nanociencia, E-28049 Madrid, Spain
| | - Colin J Lambert
- Department of Physics, University of Lancaster, Lancaster LA1 4YB, U.K
| | - Richard J Nichols
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, U.K
| | - Paul J Low
- School of Molecular Sciences, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
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12
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Palomino‐Ruiz L, Rodríguez‐González S, Fallaque JG, Márquez IR, Agraït N, Díaz C, Leary E, Cuerva JM, Campaña AG, Martín F, Millán A, González MT. Single‐Molecule Conductance of 1,4‐Azaborine Derivatives as Models of BN‐doped PAHs. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202014194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Lucía Palomino‐Ruiz
- Departamento de Química Orgánica Facultad de Ciencias Unidad de Excelencia de Química Aplicada a Biomedicina y Medioambiente (UEQ) Universidad de Granada 18071 Granada Spain
- Fundación IMDEA Nanociencia 28049 Madrid Spain
| | - Sandra Rodríguez‐González
- Departamento de Química, Módulo 13 Universidad Autónoma de Madrid 28049 Madrid Spain
- Present address: Departamento de Química Física Facultad de Ciencias Universidad de Málaga 29071 Málaga Spain
| | | | - Irene R. Márquez
- Departamento de Química Orgánica Facultad de Ciencias Unidad de Excelencia de Química Aplicada a Biomedicina y Medioambiente (UEQ) Universidad de Granada 18071 Granada Spain
- Centro de Instrumentación Científica Universidad de Granada 18071 Granada Spain
| | - Nicolás Agraït
- Fundación IMDEA Nanociencia 28049 Madrid Spain
- Departamento de Física de la Materia Condensada Universidad Autónoma de Madrid 28049 Madrid Spain
- Condensed Matter Physics Center (IFIMAC) Universidad Autónoma de Madrid 28049 Madrid Spain
| | - Cristina Díaz
- Departamento de Química, Módulo 13 Universidad Autónoma de Madrid 28049 Madrid Spain
- Present address: Departamento de Química Física Facultad de CC. Químicas Universidad Complutense de Madrid 28040 Madrid Spain
| | | | - Juan M. Cuerva
- Departamento de Química Orgánica Facultad de Ciencias Unidad de Excelencia de Química Aplicada a Biomedicina y Medioambiente (UEQ) Universidad de Granada 18071 Granada Spain
| | - Araceli G. Campaña
- Departamento de Química Orgánica Facultad de Ciencias Unidad de Excelencia de Química Aplicada a Biomedicina y Medioambiente (UEQ) Universidad de Granada 18071 Granada Spain
| | - Fernando Martín
- Fundación IMDEA Nanociencia 28049 Madrid Spain
- Departamento de Química, Módulo 13 Universidad Autónoma de Madrid 28049 Madrid Spain
- Condensed Matter Physics Center (IFIMAC) Universidad Autónoma de Madrid 28049 Madrid Spain
| | - Alba Millán
- Departamento de Química Orgánica Facultad de Ciencias Unidad de Excelencia de Química Aplicada a Biomedicina y Medioambiente (UEQ) Universidad de Granada 18071 Granada Spain
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13
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Palomino-Ruiz L, Rodríguez-González S, Fallaque JG, Márquez IR, Agraït N, Díaz C, Leary E, Cuerva JM, Campaña AG, Martín F, Millán A, González MT. Single-Molecule Conductance of 1,4-Azaborine Derivatives as Models of BN-doped PAHs. Angew Chem Int Ed Engl 2021; 60:6609-6616. [PMID: 33348468 DOI: 10.1002/anie.202014194] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 12/02/2020] [Indexed: 01/06/2023]
Abstract
The single-molecule conductance of a series of BN-acene-like derivatives has been measured by using scanning tunneling break-junction techniques. A strategic design of the target molecules has allowed us to include azaborine units in positions that unambiguously ensure electron transport through both heteroatoms, which is relevant for the development of customized BN-doped nanographenes. We show that the conductance of the anthracene azaborine derivative is comparable to that of the pristine all-carbon anthracene compound. Notably, this heteroatom substitution has also allowed us to perform similar measurements on the corresponding pentacene-like compound, which is found to have a similar conductance, thus evidencing that B-N doping could also be used to stabilize and characterize larger acenes for molecular electronics applications. Our conclusions are supported by state-of-the-art transport calculations.
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Affiliation(s)
- Lucía Palomino-Ruiz
- Departamento de Química Orgánica, Facultad de Ciencias, Unidad de Excelencia de Química Aplicada a Biomedicina y Medioambiente (UEQ), Universidad de Granada, 18071, Granada, Spain.,Fundación IMDEA Nanociencia, 28049, Madrid, Spain
| | - Sandra Rodríguez-González
- Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049, Madrid, Spain.,Present address: Departamento de Química Física, Facultad de Ciencias, Universidad de Málaga, 29071, Málaga, Spain
| | | | - Irene R Márquez
- Departamento de Química Orgánica, Facultad de Ciencias, Unidad de Excelencia de Química Aplicada a Biomedicina y Medioambiente (UEQ), Universidad de Granada, 18071, Granada, Spain.,Centro de Instrumentación Científica, Universidad de Granada, 18071, Granada, Spain
| | - Nicolás Agraït
- Fundación IMDEA Nanociencia, 28049, Madrid, Spain.,Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049, Madrid, Spain.,Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Cristina Díaz
- Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049, Madrid, Spain.,Present address: Departamento de Química Física, Facultad de CC. Químicas, Universidad Complutense de Madrid, 28040, Madrid, Spain
| | - Edmund Leary
- Fundación IMDEA Nanociencia, 28049, Madrid, Spain
| | - Juan M Cuerva
- Departamento de Química Orgánica, Facultad de Ciencias, Unidad de Excelencia de Química Aplicada a Biomedicina y Medioambiente (UEQ), Universidad de Granada, 18071, Granada, Spain
| | - Araceli G Campaña
- Departamento de Química Orgánica, Facultad de Ciencias, Unidad de Excelencia de Química Aplicada a Biomedicina y Medioambiente (UEQ), Universidad de Granada, 18071, Granada, Spain
| | - Fernando Martín
- Fundación IMDEA Nanociencia, 28049, Madrid, Spain.,Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049, Madrid, Spain.,Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Alba Millán
- Departamento de Química Orgánica, Facultad de Ciencias, Unidad de Excelencia de Química Aplicada a Biomedicina y Medioambiente (UEQ), Universidad de Granada, 18071, Granada, Spain
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14
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Grace IM, Olsen G, Hurtado-Gallego J, Rincón-García L, Rubio-Bollinger G, Bryce MR, Agraït N, Lambert CJ. Connectivity dependent thermopower of bridged biphenyl molecules in single-molecule junctions. Nanoscale 2020; 12:14682-14688. [PMID: 32618309 DOI: 10.1039/d0nr04001k] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We report measurements on gold|single-molecule|gold junctions, using a modified scanning tunneling microscope-break junction (STM-BJ) technique, of the Seebeck coefficient and electrical conductance of a series of bridged biphenyl molecules, with meta connectivities to pyridyl anchor groups. These data are compared with a previously reported study of para-connected analogues. In agreement with a tight binding model, the electrical conductance of the meta series is relatively low and is sensitive to the nature of the bridging groups, whereas in the para case the conductance is higher and relatively insensitive to the presence of the bridging groups. This difference in sensitivity arises from the presence of destructive quantum interference in the π system of the unbridged aromatic core, which is alleviated to different degrees by the presence of bridging groups. More precisely, the Seebeck coefficient of meta-connected molecules was found to vary between -6.1 μV K-1 and -14.1 μV K-1, whereas that of the para-connected molecules varied from -5.5 μV K-1 and -9.0 μV K-1.
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Affiliation(s)
- Iain M Grace
- Department of Physics, Lancaster University, Lancaster, LA1 4YB, UK.
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15
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Ryu YK, Carrascoso F, López-Nebreda R, Agraït N, Frisenda R, Castellanos-Gomez A. Microheater Actuators as a Versatile Platform for Strain Engineering in 2D Materials. Nano Lett 2020; 20:5339-5345. [PMID: 32491864 DOI: 10.1021/acs.nanolett.0c01706] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We present microfabricated thermal actuators to engineer the biaxial strain in two-dimensional (2D) materials. These actuators are based on microheater circuits patterned onto the surface of a polymer with a high thermal expansion coefficient. By running current through the microheater one can vary the temperature of the polymer and induce a controlled biaxial expansion of its surface. This controlled biaxial expansion can be transduced to biaxial strain to 2D materials, placed onto the polymer surface, which in turn induces a shift of the optical spectrum. Our thermal strain actuators can reach a maximum biaxial strain of 0.64%, and they can be modulated at frequencies up to 8 Hz. The compact geometry of these actuators results in a negligible spatial drift of 0.03 μm/°C, which facilitates their integration in optical spectroscopy measurements. We illustrate the potential of this strain engineering platform to fabricate a strain-actuated optical modulator with single-layer MoS2.
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Affiliation(s)
- Yu Kyoung Ryu
- Materials Science Factory, Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), E-28049 Madrid, Spain
| | - Felix Carrascoso
- Materials Science Factory, Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), E-28049 Madrid, Spain
| | - Rubén López-Nebreda
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Nicolás Agraït
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Condensed Matter Physics Center (IFIMAC) and Instituto "Nicolás Cabrera", Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Fundación IMDEA Nanociencia, Ciudad Universitaria de Cantoblanco, E-28049 Madrid, Spain
| | - Riccardo Frisenda
- Materials Science Factory, Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), E-28049 Madrid, Spain
| | - Andres Castellanos-Gomez
- Materials Science Factory, Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), E-28049 Madrid, Spain
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16
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Xu W, Leary E, Hou S, Sangtarash S, González MT, Rubio‐Bollinger G, Wu Q, Sadeghi H, Tejerina L, Christensen KE, Agraït N, Higgins SJ, Lambert CJ, Nichols RJ, Anderson HL. Unusual Length Dependence of the Conductance in Cumulene Molecular Wires. Angew Chem Int Ed Engl 2019; 58:8378-8382. [PMID: 31026371 PMCID: PMC6563095 DOI: 10.1002/anie.201901228] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 04/22/2019] [Indexed: 01/29/2023]
Abstract
Cumulenes are sometimes described as "metallic" because an infinitely long cumulene would have the band structure of a metal. Herein, we report the single-molecule conductance of a series of cumulenes and cumulene analogues, where the number of consecutive C=C bonds in the core is n=1, 2, 3, and 5. The [n]cumulenes with n=3 and 5 have almost the same conductance, and they are both more conductive than the alkene (n=1). This is remarkable because molecular conductance normally falls exponentially with length. The conductance of the allene (n=2) is much lower, because of its twisted geometry. Computational simulations predict a similar trend to the experimental results and indicate that the low conductance of the allene is a general feature of [n]cumulenes where n is even. The lack of length dependence in the conductance of [3] and [5]cumulenes is attributed to the strong decrease in the HOMO-LUMO gap with increasing length.
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Affiliation(s)
- Wenjun Xu
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryOxfordOX1 3TAUK
| | - Edmund Leary
- Department of ChemistryDonnan and Robert Robinson LaboratoriesUniversity of LiverpoolLiverpoolL69 7ZDUK
- Surface Science Research CentreUniversity of LiverpoolOxford StreetLiverpoolL69 3BXUK
| | - Songjun Hou
- Department of PhysicsLancaster UniversityLancasterLA1 4YWUK
| | | | - M. Teresa González
- Instituto Madrileño de Estudios Avanzados (IMDEA)Calle Faraday 9, Campus Universitario de Cantoblanco28049MadridSpain
| | - Gabino Rubio‐Bollinger
- Departamento de Física de la Materia CondensadaIFIMAC and Instituto “Nicolás Cabrera”Universidad Autónoma de Madrid28049MadridSpain
| | - Qingqing Wu
- Department of PhysicsLancaster UniversityLancasterLA1 4YWUK
| | - Hatef Sadeghi
- Department of PhysicsLancaster UniversityLancasterLA1 4YWUK
| | - Lara Tejerina
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryOxfordOX1 3TAUK
| | | | - Nicolás Agraït
- Instituto Madrileño de Estudios Avanzados (IMDEA)Calle Faraday 9, Campus Universitario de Cantoblanco28049MadridSpain
- Departamento de Física de la Materia CondensadaIFIMAC and Instituto “Nicolás Cabrera”Universidad Autónoma de Madrid28049MadridSpain
| | - Simon J. Higgins
- Department of ChemistryDonnan and Robert Robinson LaboratoriesUniversity of LiverpoolLiverpoolL69 7ZDUK
| | | | - Richard J. Nichols
- Department of ChemistryDonnan and Robert Robinson LaboratoriesUniversity of LiverpoolLiverpoolL69 7ZDUK
- Surface Science Research CentreUniversity of LiverpoolOxford StreetLiverpoolL69 3BXUK
| | - Harry L. Anderson
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryOxfordOX1 3TAUK
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17
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Maeso D, Pakdel S, Santos H, Agraït N, Palacios JJ, Prada E, Rubio-Bollinger G. Strong modulation of optical properties in rippled 2D GaSe via strain engineering. Nanotechnology 2019; 30:24LT01. [PMID: 30822757 DOI: 10.1088/1361-6528/ab0bc1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Few-layer GaSe is one of the latest additions to the family of two-dimensional semiconducting crystals whose properties under strain are still relatively unexplored. Here, we study rippled nanosheets that exhibit a periodic compressive and tensile strain of up to 5%. The strain profile modifies the local optoelectronic properties of the alternating compressive and tensile regions, which translates into a remarkable shift of the optical absorption band-edge of up to 1.2 eV between crests and valleys. Our experimental observations are supported by theoretical results from density functional theory calculations performed for monolayers and multilayers (up to seven layers) under tensile and compressive strain. This large band gap tunability can be explained through a combined analysis of the elastic response of Ga atoms to strain and the symmetry of the wave functions.
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Affiliation(s)
- David Maeso
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, E-28049, Madrid, Spain
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18
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Xu W, Leary E, Hou S, Sangtarash S, González MT, Rubio‐Bollinger G, Wu Q, Sadeghi H, Tejerina L, Christensen KE, Agraït N, Higgins SJ, Lambert CJ, Nichols RJ, Anderson HL. Unusual Length Dependence of the Conductance in Cumulene Molecular Wires. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201901228] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Wenjun Xu
- Department of ChemistryUniversity of OxfordChemistry Research Laboratory Oxford OX1 3TA UK
| | - Edmund Leary
- Department of ChemistryDonnan and Robert Robinson LaboratoriesUniversity of Liverpool Liverpool L69 7ZD UK
- Surface Science Research CentreUniversity of Liverpool Oxford Street Liverpool L69 3BX UK
| | - Songjun Hou
- Department of PhysicsLancaster University Lancaster LA1 4YW UK
| | - Sara Sangtarash
- Department of PhysicsLancaster University Lancaster LA1 4YW UK
| | - M. Teresa González
- Instituto Madrileño de Estudios Avanzados (IMDEA) Calle Faraday 9, Campus Universitario de Cantoblanco 28049 Madrid Spain
| | - Gabino Rubio‐Bollinger
- Departamento de Física de la Materia CondensadaIFIMAC and Instituto “Nicolás Cabrera”Universidad Autónoma de Madrid 28049 Madrid Spain
| | - Qingqing Wu
- Department of PhysicsLancaster University Lancaster LA1 4YW UK
| | - Hatef Sadeghi
- Department of PhysicsLancaster University Lancaster LA1 4YW UK
| | - Lara Tejerina
- Department of ChemistryUniversity of OxfordChemistry Research Laboratory Oxford OX1 3TA UK
| | - Kirsten E. Christensen
- Department of ChemistryUniversity of OxfordChemistry Research Laboratory Oxford OX1 3TA UK
| | - Nicolás Agraït
- Instituto Madrileño de Estudios Avanzados (IMDEA) Calle Faraday 9, Campus Universitario de Cantoblanco 28049 Madrid Spain
- Departamento de Física de la Materia CondensadaIFIMAC and Instituto “Nicolás Cabrera”Universidad Autónoma de Madrid 28049 Madrid Spain
| | - Simon J. Higgins
- Department of ChemistryDonnan and Robert Robinson LaboratoriesUniversity of Liverpool Liverpool L69 7ZD UK
| | | | - Richard J. Nichols
- Department of ChemistryDonnan and Robert Robinson LaboratoriesUniversity of Liverpool Liverpool L69 7ZD UK
- Surface Science Research CentreUniversity of Liverpool Oxford Street Liverpool L69 3BX UK
| | - Harry L. Anderson
- Department of ChemistryUniversity of OxfordChemistry Research Laboratory Oxford OX1 3TA UK
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19
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Yzambart G, Rincón-García L, Al-Jobory AA, Ismael AK, Rubio-Bollinger G, Lambert CJ, Agraït N, Bryce MR. Thermoelectric Properties of 2,7-Dipyridylfluorene Derivatives in Single-Molecule Junctions. J Phys Chem C Nanomater Interfaces 2018; 122:27198-27204. [PMID: 31080539 PMCID: PMC6503582 DOI: 10.1021/acs.jpcc.8b08488] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 10/23/2018] [Indexed: 05/03/2023]
Abstract
A series of 2,7-dipyridylfluorene derivatives have been synthesized with different substituents (2H, 2Me, 2OMe, 2CF3, and O) at the C(9) position. Experimental measurements on gold|single-molecule|gold junctions, using a modified scanning tunneling microscope-break-junction technique, show that the C(9) substituent has little effect on the conductance, although there is a more significant influence on the thermopower, with the Seebeck coefficient varying by a factor of 1.65 within the series. The combined experimental and computational study, using density functional theory calculations, provides insights into the interplay of conductance and thermopower in single-molecule junctions and is a guide for new strategies for thermopower modulation in single-molecule junctions.
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Affiliation(s)
- Gilles Yzambart
- Department
of Chemistry, Durham University, Durham DH1 3LE, U.K.
| | - Laura Rincón-García
- Departamento de Física de
la Materia Condensada and Condensed Matter
Physics Center (IFIMAC) and Instituto Universitario de Ciencia de
Materiales “Nicolás Cabrera” (INC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Instituto
Madrileño de Estudios Avanzados en Nanociencia IMDEA-Nanociencia, E-28049 Madrid, Spain
| | - Alaa A. Al-Jobory
- Department
of Physics, Lancaster University, Lancaster LA1 4YB, U.K.
- Department
of Physics, College of Education for Pure Science, University of Anbar, Ramadi P.O. Box
55, Anbar, Iraq
| | - Ali K. Ismael
- Department
of Physics, Lancaster University, Lancaster LA1 4YB, U.K.
- Department
of Physics, College of Education for Pure Science, Tikrit University, Saladin P.O. Box
42, Tikrit, Iraq
| | - Gabino Rubio-Bollinger
- Departamento de Física de
la Materia Condensada and Condensed Matter
Physics Center (IFIMAC) and Instituto Universitario de Ciencia de
Materiales “Nicolás Cabrera” (INC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Colin J. Lambert
- Department
of Physics, Lancaster University, Lancaster LA1 4YB, U.K.
| | - Nicolás Agraït
- Departamento de Física de
la Materia Condensada and Condensed Matter
Physics Center (IFIMAC) and Instituto Universitario de Ciencia de
Materiales “Nicolás Cabrera” (INC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Instituto
Madrileño de Estudios Avanzados en Nanociencia IMDEA-Nanociencia, E-28049 Madrid, Spain
| | - Martin R. Bryce
- Department
of Chemistry, Durham University, Durham DH1 3LE, U.K.
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20
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Quereda J, San-Jose P, Parente V, Vaquero-Garzon L, Molina-Mendoza AJ, Agraït N, Rubio-Bollinger G, Guinea F, Roldán R, Castellanos-Gomez A. Strong Modulation of Optical Properties in Black Phosphorus through Strain-Engineered Rippling. Nano Lett 2016; 16:2931-7. [PMID: 27042865 DOI: 10.1021/acs.nanolett.5b04670] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Controlling the bandgap through local-strain engineering is an exciting avenue for tailoring optoelectronic materials. Two-dimensional crystals are particularly suited for this purpose because they can withstand unprecedented nonhomogeneous deformations before rupture; one can literally bend them and fold them up almost like a piece of paper. Here, we study multilayer black phosphorus sheets subjected to periodic stress to modulate their optoelectronic properties. We find a remarkable shift of the optical absorption band-edge of up to ∼0.7 eV between the regions under tensile and compressive stress, greatly exceeding the strain tunability reported for transition metal dichalcogenides. This observation is supported by theoretical models that also predict that this periodic stress modulation can yield to quantum confinement of carriers at low temperatures. The possibility of generating large strain-induced variations in the local density of charge carriers opens the door for a variety of applications including photovoltaics, quantum optics, and two-dimensional optoelectronic devices.
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Affiliation(s)
- Jorge Quereda
- Department de Física de la Materia Condensada, Universidad Autónoma de Madrid , 28049 Madrid, Spain
| | - Pablo San-Jose
- Instituto de Ciencia de Materiales de Madrid, CSIC , Sor Juana Ines de la Cruz 3, 28049 Madrid, Spain
| | - Vincenzo Parente
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia) , Campus de Cantoblanco, E-28049 Madrid, Spain
| | - Luis Vaquero-Garzon
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia) , Campus de Cantoblanco, E-28049 Madrid, Spain
| | - Aday J Molina-Mendoza
- Department de Física de la Materia Condensada, Universidad Autónoma de Madrid , 28049 Madrid, Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia) , Campus de Cantoblanco, E-28049 Madrid, Spain
| | - Nicolás Agraït
- Department de Física de la Materia Condensada, Universidad Autónoma de Madrid , 28049 Madrid, Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia) , Campus de Cantoblanco, E-28049 Madrid, Spain
- Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid , E-28049 Madrid, Spain
| | - Gabino Rubio-Bollinger
- Department de Física de la Materia Condensada, Universidad Autónoma de Madrid , 28049 Madrid, Spain
- Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid , E-28049 Madrid, Spain
| | - Francisco Guinea
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia) , Campus de Cantoblanco, E-28049 Madrid, Spain
| | - Rafael Roldán
- Instituto de Ciencia de Materiales de Madrid, CSIC , Sor Juana Ines de la Cruz 3, 28049 Madrid, Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia) , Campus de Cantoblanco, E-28049 Madrid, Spain
| | - Andres Castellanos-Gomez
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia) , Campus de Cantoblanco, E-28049 Madrid, Spain
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21
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Castellanos-Gomez A, Quereda J, van der Meulen HP, Agraït N, Rubio-Bollinger G. Spatially resolved optical absorption spectroscopy of single- and few-layer MoS₂ by hyperspectral imaging. Nanotechnology 2016; 27:115705. [PMID: 26876671 DOI: 10.1088/0957-4484/27/11/115705] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The possibility of spatially resolving the optical properties of atomically thin materials is especially appealing as they can be modulated at the micro- and nanoscale by reducing their thickness, changing the doping level or applying a mechanical deformation. Therefore, optical spectroscopy techniques with high spatial resolution are necessary to get a deeper insight into the properties of two-dimensional (2D) materials. Here we study the optical absorption of single- and few-layer molybdenum disulfide (MoS2) in the spectral range from 1.24 eV to 3.22 eV (385 nm to 1000 nm) by developing a hyperspectral imaging technique that allows one to probe the optical properties with diffraction limited spatial resolution. We find hyperspectral imaging very suited to study indirect bandgap semiconductors, unlike photoluminescence which only provides high luminescence yield for direct gap semiconductors. Moreover, this work opens the door to study the spatial variation of the optical properties of other 2D systems, including non-semiconducting materials where scanning photoluminescence cannot be employed.
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Affiliation(s)
- Andres Castellanos-Gomez
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), 28049 Madrid, Spain
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22
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Navarro-Moratalla E, Island JO, Mañas-Valero S, Pinilla-Cienfuegos E, Castellanos-Gomez A, Quereda J, Rubio-Bollinger G, Chirolli L, Silva-Guillén JA, Agraït N, Steele GA, Guinea F, van der Zant HSJ, Coronado E. Enhanced superconductivity in atomically thin TaS2. Nat Commun 2016; 7:11043. [PMID: 26984768 PMCID: PMC5512558 DOI: 10.1038/ncomms11043] [Citation(s) in RCA: 127] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Accepted: 02/15/2016] [Indexed: 12/14/2022] Open
Abstract
The ability to exfoliate layered materials down to the single layer limit has presented the opportunity to understand how a gradual reduction in dimensionality affects the properties of bulk materials. Here we use this top–down approach to address the problem of superconductivity in the two-dimensional limit. The transport properties of electronic devices based on 2H tantalum disulfide flakes of different thicknesses are presented. We observe that superconductivity persists down to the thinnest layer investigated (3.5 nm), and interestingly, we find a pronounced enhancement in the critical temperature from 0.5 to 2.2 K as the layers are thinned down. In addition, we propose a tight-binding model, which allows us to attribute this phenomenon to an enhancement of the effective electron–phonon coupling constant. This work provides evidence that reducing the dimensionality can strengthen superconductivity as opposed to the weakening effect that has been reported in other 2D materials so far. As a material's thickness decreases towards the atomic-scale, dimensional confinement may promote behaviour not found in the bulk, with potential technological applications. Here, the authors study superconductivity in TaS2 as it is mechanically exfoliated towards the two-dimensional limit.
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Affiliation(s)
- Efrén Navarro-Moratalla
- Universidad de Valencia (ICMol), Catedrático José Beltrán Martínez n° 2, Paterna 46980, Spain
| | - Joshua O Island
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, Delft 2628 CJ, The Netherlands
| | - Samuel Mañas-Valero
- Universidad de Valencia (ICMol), Catedrático José Beltrán Martínez n° 2, Paterna 46980, Spain
| | | | - Andres Castellanos-Gomez
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, Delft 2628 CJ, The Netherlands
| | - Jorge Quereda
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Campus de Cantoblanco, Madrid 28049, Spain
| | - Gabino Rubio-Bollinger
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Campus de Cantoblanco, Madrid 28049, Spain.,Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Madrid 28049, Spain
| | - Luca Chirolli
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA- Nanociencia), Calle Farady 9, Cantoblanco, Madrid 28049, Spain
| | - Jose Angel Silva-Guillén
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA- Nanociencia), Calle Farady 9, Cantoblanco, Madrid 28049, Spain
| | - Nicolás Agraït
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Campus de Cantoblanco, Madrid 28049, Spain.,Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Madrid 28049, Spain.,Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA- Nanociencia), Calle Farady 9, Cantoblanco, Madrid 28049, Spain
| | - Gary A Steele
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, Delft 2628 CJ, The Netherlands
| | - Francisco Guinea
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA- Nanociencia), Calle Farady 9, Cantoblanco, Madrid 28049, Spain
| | - Herre S J van der Zant
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, Delft 2628 CJ, The Netherlands
| | - Eugenio Coronado
- Universidad de Valencia (ICMol), Catedrático José Beltrán Martínez n° 2, Paterna 46980, Spain
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23
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Rincón-García L, Ismael AK, Evangeli C, Grace I, Rubio-Bollinger G, Porfyrakis K, Agraït N, Lambert CJ. Molecular design and control of fullerene-based bi-thermoelectric materials. Nat Mater 2016; 15:289-93. [PMID: 26641017 DOI: 10.1038/nmat4487] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 10/26/2015] [Indexed: 05/03/2023]
Abstract
Molecular junctions are a versatile test bed for investigating nanoscale thermoelectricity and contribute to the design of new cost-effective environmentally friendly organic thermoelectric materials. It was suggested that transport resonances associated with discrete molecular levels could play a key role in thermoelectric performance, but no direct experimental evidence has been reported. Here we study single-molecule junctions of the endohedral fullerene Sc3N@C80 connected to gold electrodes using a scanning tunnelling microscope. We find that the magnitude and sign of the thermopower depend strongly on the orientation of the molecule and on applied pressure. Our calculations show that Sc3N inside the fullerene cage creates a sharp resonance near the Fermi level, whose energetic location, and hence the thermopower, can be tuned by applying pressure. These results reveal that Sc3N@C80 is a bi-thermoelectric material, exhibiting both positive and negative thermopower, and provide an unambiguous demonstration of the importance of transport resonances in molecular junctions.
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Affiliation(s)
- Laura Rincón-García
- Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia IMDEA-Nanociencia, E-28049 Madrid, Spain
| | - Ali K Ismael
- Department of Physics, Lancaster University, Lancaster LA1 4YW, UK
- Department of Physics, College of Education for Pure Science, Tikrit University, Tikreet 34001, Iraq
| | - Charalambos Evangeli
- Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Iain Grace
- Department of Physics, Lancaster University, Lancaster LA1 4YW, UK
| | - Gabino Rubio-Bollinger
- Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Instituto Universitario de Ciencia de Materiales Nicolás Cabrera, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | | | - Nicolás Agraït
- Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia IMDEA-Nanociencia, E-28049 Madrid, Spain
- Instituto Universitario de Ciencia de Materiales Nicolás Cabrera, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Colin J Lambert
- Department of Physics, Lancaster University, Lancaster LA1 4YW, UK
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24
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Abstract
The measurement of thermopower in molecular junctions offers complementary information to conductance measurements and is becoming essential for the understanding of transport processes at the nanoscale.
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Affiliation(s)
- Laura Rincón-García
- Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC)
- Universidad Autónoma de Madrid
- E-28049 Madrid
- Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia IMDEA-Nanociencia
| | - Charalambos Evangeli
- Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC)
- Universidad Autónoma de Madrid
- E-28049 Madrid
- Spain
| | - Gabino Rubio-Bollinger
- Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC)
- Universidad Autónoma de Madrid
- E-28049 Madrid
- Spain
- Instituto Universitario de Ciencia de Materiales “Nicolás Cabrera”
| | - Nicolás Agraït
- Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC)
- Universidad Autónoma de Madrid
- E-28049 Madrid
- Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia IMDEA-Nanociencia
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25
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Miguel D, Álvarez de Cienfuegos L, Martín-Lasanta A, Morcillo SP, Zotti LA, Leary E, Bürkle M, Asai Y, Jurado R, Cárdenas DJ, Rubio-Bollinger G, Agraït N, Cuerva JM, González MT. Toward Multiple Conductance Pathways with Heterocycle-Based Oligo(phenyleneethynylene) Derivatives. J Am Chem Soc 2015; 137:13818-26. [DOI: 10.1021/jacs.5b05637] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Delia Miguel
- Departamento
de Química Orgánica, Universidad de Granada, C. U. Fuentenueva,
Avda. Severo Ochoa s/n, E-18071 Granada, Spain
| | - Luis Álvarez de Cienfuegos
- Departamento
de Química Orgánica, Universidad de Granada, C. U. Fuentenueva,
Avda. Severo Ochoa s/n, E-18071 Granada, Spain
| | - Ana Martín-Lasanta
- Fundación
IMDEA Nanociencia, Ciudad Universitaria de Cantoblanco, E-28049 Madrid, Spain
| | - Sara P. Morcillo
- Departamento
de Química Orgánica, Universidad de Granada, C. U. Fuentenueva,
Avda. Severo Ochoa s/n, E-18071 Granada, Spain
| | - Linda A. Zotti
- Departamento
of Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, Ciudad Universitaria de Cantoblanco, E-28049 Madrid, Spain
| | - Edmund Leary
- Fundación
IMDEA Nanociencia, Ciudad Universitaria de Cantoblanco, E-28049 Madrid, Spain
| | - Marius Bürkle
- Nanomaterials
Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568, Japan
| | - Yoshihiro Asai
- Nanomaterials
Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568, Japan
| | - Rocío Jurado
- Departamento
de Química Orgánica, Universidad de Granada, C. U. Fuentenueva,
Avda. Severo Ochoa s/n, E-18071 Granada, Spain
| | - Diego J. Cárdenas
- Departamento
de Química Orgánica, Universidad Autónoma de Madrid, Ciudad Universitaria de Cantoblanco, E-28049 Madrid, Spain
| | - Gabino Rubio-Bollinger
- Departamento
de Física de la Materia Condensada and Condensed Matter Physics
Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Instituto
“Nicolás Cabrera”, Universidad Autónoma de Madrid, Ciudad Universitaria de Cantoblanco, E-28049 Madrid, Spain
| | - Nicolás Agraït
- Fundación
IMDEA Nanociencia, Ciudad Universitaria de Cantoblanco, E-28049 Madrid, Spain
- Departamento
de Física de la Materia Condensada and Condensed Matter Physics
Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Instituto
“Nicolás Cabrera”, Universidad Autónoma de Madrid, Ciudad Universitaria de Cantoblanco, E-28049 Madrid, Spain
| | - Juan M. Cuerva
- Departamento
de Química Orgánica, Universidad de Granada, C. U. Fuentenueva,
Avda. Severo Ochoa s/n, E-18071 Granada, Spain
| | - M. Teresa González
- Fundación
IMDEA Nanociencia, Ciudad Universitaria de Cantoblanco, E-28049 Madrid, Spain
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26
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Sherif S, Rubio-Bollinger G, Pinilla-Cienfuegos E, Coronado E, Cuevas JC, Agraït N. Current rectification in a single molecule diode: the role of electrode coupling. Nanotechnology 2015; 26:291001. [PMID: 26133791 DOI: 10.1088/0957-4484/26/29/291001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We demonstrate large rectification ratios (> 100) in single-molecule junctions based on a metal-oxide cluster (polyoxometalate), using a scanning tunneling microscope (STM) both at ambient conditions and at low temperature. These rectification ratios are the largest ever observed in a single-molecule junction, and in addition these junctions sustain current densities larger than 10(5) A cm(-2). By following the variation of the I-V characteristics with tip-molecule separation we demonstrate unambiguously that rectification is due to asymmetric coupling to the electrodes of a molecule with an asymmetric level structure. This mechanism can be implemented in other type of molecular junctions using both organic and inorganic molecules and provides a simple strategy for the rational design of molecular diodes.
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Affiliation(s)
- Siya Sherif
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanoscience), Faraday, 9, Ciudad Universitaria de Cantoblanco, 28049, Madrid, Spain. Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Facultad de Ciencias, c/ Francisco Tomás y Valiente, 7 Universidad Autónoma de Madrid 28049 Madrid, Spain
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27
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García R, Herranz MÁ, Leary E, González MT, Bollinger GR, Bürkle M, Zotti LA, Asai Y, Pauly F, Cuevas JC, Agraït N, Martín N. Single-molecule conductance of a chemically modified, π-extended tetrathiafulvalene and its charge-transfer complex with F4TCNQ. Beilstein J Org Chem 2015. [PMID: 26199662 PMCID: PMC4505095 DOI: 10.3762/bjoc.11.120] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
We describe the synthesis and single-molecule electrical transport properties of a molecular wire containing a π-extended tetrathiafulvalene (exTTF) group and its charge-transfer complex with F4TCNQ. We form single-molecule junctions using the in situ break junction technique using a homebuilt scanning tunneling microscope with a range of conductance between 10 G0 down to 10(-7) G0. Within this range we do not observe a clear conductance signature of the neutral parent molecule, suggesting either that its conductance is too low or that it does not form a stable junction. Conversely, we do find a clear conductance signature in the experiments carried out on the charge-transfer complex. Due to the fact we expected this species to have a higher conductance than the neutral molecule, we believe this supports the idea that the conductance of the neutral molecule is very low, below our measurement sensitivity. This idea is further supported by theoretical calculations. To the best of our knowledge, these are the first reported single-molecule conductance measurements on a molecular charge-transfer species.
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Affiliation(s)
- Raúl García
- Departamento de Química Orgánica, Facultad de Química, Universidad Complutense, E-28040 Madrid, Spain
| | - M Ángeles Herranz
- Departamento de Química Orgánica, Facultad de Química, Universidad Complutense, E-28040 Madrid, Spain
| | - Edmund Leary
- Fundación IMDEA Nanoscience, Campus de Cantoblanco, Universidad Autónoma, E-28048 Madrid, Spain
| | - M Teresa González
- Fundación IMDEA Nanoscience, Campus de Cantoblanco, Universidad Autónoma, E-28048 Madrid, Spain
| | - Gabino Rubio Bollinger
- Departamento de Física de la Materia Condensada, and Instituto "Nicolás Cabrera", Universidad Autonoma de Madrid, E-28049 Madrid, Spain
| | - Marius Bürkle
- Nanosystem Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568, Japan
| | - Linda A Zotti
- Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, Spain
| | - Yoshihiro Asai
- Nanosystem Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568, Japan
| | - Fabian Pauly
- Department of Physics, University of Konstanz, D-78457 Konstanz, Germany
| | - Juan Carlos Cuevas
- Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, Spain
| | - Nicolás Agraït
- Fundación IMDEA Nanoscience, Campus de Cantoblanco, Universidad Autónoma, E-28048 Madrid, Spain ; Departamento de Física de la Materia Condensada, and Instituto "Nicolás Cabrera", Universidad Autonoma de Madrid, E-28049 Madrid, Spain
| | - Nazario Martín
- Departamento de Química Orgánica, Facultad de Química, Universidad Complutense, E-28040 Madrid, Spain ; Fundación IMDEA Nanoscience, Campus de Cantoblanco, Universidad Autónoma, E-28048 Madrid, Spain
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28
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Evangeli C, Matt M, Rincón-García L, Pauly F, Nielaba P, Rubio-Bollinger G, Cuevas JC, Agraït N. Quantum thermopower of metallic atomic-size contacts at room temperature. Nano Lett 2015; 15:1006-11. [PMID: 25607343 DOI: 10.1021/nl503853v] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We report conductance and thermopower measurements of metallic atomic-size contacts, namely gold and platinum, using a scanning tunneling microscope (STM) at room temperature. We find that few-atom gold contacts have an average negative thermopower, whereas platinum contacts present a positive thermopower, showing that for both metals, the sign of the thermopower in the nanoscale differs from that of bulk wires. We also find that the magnitude of the thermopower exhibits minima at the maxima of the conductance histogram in the case of gold nanocontacts while for platinum it presents large fluctuations. Tight-binding calculations and Green's function techniques, together with molecular dynamics simulations, show that these observations can be understood in the context of the Landauer-Büttiker picture of coherent transport in atomic-scale wires. In particular, we show that the differences in the thermopower between these two metals are due to the fact that the elastic transport is dominated by the 6s orbitals in the case of gold and by the 5d orbitals in the case of platinum.
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Affiliation(s)
- Charalambos Evangeli
- Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid , E-28049 Madrid, Spain
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Leary E, La Rosa A, González MT, Rubio-Bollinger G, Agraït N, Martín N. Incorporating single molecules into electrical circuits. The role of the chemical anchoring group. Chem Soc Rev 2015; 44:920-42. [DOI: 10.1039/c4cs00264d] [Citation(s) in RCA: 134] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Constructing electronic circuits containing singly wired molecules is at the frontier of electrical device miniaturisation. Understanding the behaviour of different anchoring groups is key to this goal because of their significant role in determining the properties of the junction.
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Affiliation(s)
- Edmund Leary
- IMDEA Nanociencia
- C/Faraday 9
- 28049 Madrid
- Spain
- Depto. Física de la Materia Condensada Mod. 3-610 – Universidad Autónoma de Madrid
| | - Andrea La Rosa
- Departamento de Química Orgánica
- Facultad de Ciencias Quıímicas
- Universidad Complutense de Madrid
- Madrid
- Spain
| | | | - Gabino Rubio-Bollinger
- Depto. Física de la Materia Condensada Mod. 3-610 – Universidad Autónoma de Madrid
- 28049 Madrid
- Spain
| | - Nicolás Agraït
- IMDEA Nanociencia
- C/Faraday 9
- 28049 Madrid
- Spain
- Depto. Física de la Materia Condensada Mod. 3-610 – Universidad Autónoma de Madrid
| | - Nazario Martín
- IMDEA Nanociencia
- C/Faraday 9
- 28049 Madrid
- Spain
- Departamento de Química Orgánica
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30
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La Rosa A, Gillemot K, Leary E, Evangeli C, González MT, Filippone S, Rubio-Bollinger G, Agraït N, Lambert CJ, Martín N. Does a Cyclopropane Ring Enhance the Electronic Communication in Dumbbell-Type C60 Dimers? J Org Chem 2014; 79:4871-7. [DOI: 10.1021/jo500342x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Andrea La Rosa
- Departamento
de Química Orgánica, Facultad de Química, Universidad Complutense, E 28040 Madrid, Spain
| | - Katalin Gillemot
- Department
of Physics, Lancaster University, Lancaster LA1 4YB, U.K
| | - Edmund Leary
- IMDEA-Nanoscience,
Campus de Cantoblanco, Calle Faraday 9, Ciudad Universitaria de Cantoblanco, 28049 Madrid, Spain
- Laboratorio
de Bajas Temperaturas, Departamento de Física de la Materia
Condensada Módulo 13, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Charalambos Evangeli
- Laboratorio
de Bajas Temperaturas, Departamento de Física de la Materia
Condensada Módulo 13, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - María Teresa González
- IMDEA-Nanoscience,
Campus de Cantoblanco, Calle Faraday 9, Ciudad Universitaria de Cantoblanco, 28049 Madrid, Spain
| | - Salvatore Filippone
- Departamento
de Química Orgánica, Facultad de Química, Universidad Complutense, E 28040 Madrid, Spain
| | - Gabino Rubio-Bollinger
- Laboratorio
de Bajas Temperaturas, Departamento de Física de la Materia
Condensada Módulo 13, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Nicolás Agraït
- IMDEA-Nanoscience,
Campus de Cantoblanco, Calle Faraday 9, Ciudad Universitaria de Cantoblanco, 28049 Madrid, Spain
- Laboratorio
de Bajas Temperaturas, Departamento de Física de la Materia
Condensada Módulo 13, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Colin J. Lambert
- Department
of Physics, Lancaster University, Lancaster LA1 4YB, U.K
| | - Nazario Martín
- Departamento
de Química Orgánica, Facultad de Química, Universidad Complutense, E 28040 Madrid, Spain
- IMDEA-Nanoscience,
Campus de Cantoblanco, Calle Faraday 9, Ciudad Universitaria de Cantoblanco, 28049 Madrid, Spain
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31
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Molina-Mendoza AJ, Rodrigo JG, Island J, Burzuri E, Rubio-Bollinger G, van der Zant HSJ, Agraït N. Note: long-range scanning tunneling microscope for the study of nanostructures on insulating substrates. Rev Sci Instrum 2014; 85:026105. [PMID: 24593405 DOI: 10.1063/1.4864196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The scanning tunneling microscope (STM) is a powerful tool for studying the electronic properties at the atomic level, however, it is of relatively small scanning range and the fact that it can only operate on conducting samples prevents its application to study heterogeneous samples consisting of conducting and insulating regions. Here we present a long-range scanning tunneling microscope capable of detecting conducting micro and nanostructures on insulating substrates using a technique based on the capacitance between the tip and the sample and performing STM studies.
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Affiliation(s)
- Aday J Molina-Mendoza
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Campus de Cantoblanco, E-28049 Madrid, Spain
| | - José G Rodrigo
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Campus de Cantoblanco, E-28049 Madrid, Spain
| | - Joshua Island
- Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, The Netherlands
| | - Enrique Burzuri
- Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, The Netherlands
| | - Gabino Rubio-Bollinger
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Campus de Cantoblanco, E-28049 Madrid, Spain
| | - Herre S J van der Zant
- Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, The Netherlands
| | - Nicolás Agraït
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Campus de Cantoblanco, E-28049 Madrid, Spain
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32
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Gillemot K, Evangeli C, Leary E, La Rosa A, González MT, Filippone S, Grace I, Rubio-Bollinger G, Ferrer J, Martín N, Lambert CJ, Agraït N. A detailed experimental and theoretical study into the properties of C60 dumbbell junctions. Small 2013; 9:3812-3822. [PMID: 23630169 DOI: 10.1002/smll.201300310] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 03/04/2013] [Indexed: 06/02/2023]
Abstract
A combined experimental and theoretical investigation is carried out into the electrical transport across a fullerene dumbbell one-molecule junction. The newly designed molecule comprises two C60 s connected to a fluorene backbone via cyclopropyl groups. It is wired between gold electrodes under ambient conditions by pressing the tip of a scanning tunnelling microscope (STM) onto one of the C60 groups. The STM allows us to identify a single molecule before the junction is formed through imaging, which means unambiguously that only one molecule is wired. Once lifted, the same molecule could be wired many times as it was strongly fixed to the tip, and a high conductance state close to 10(-2) G0 is found. The results also suggest that the relative conductance fluctuations are low as a result of the low mobility of the molecule. Theoretical analysis indicates that the molecule is connected directly to one electrode through the central fluorene, and that to bind it to the gold fully it has to be pushed through a layer of adsorbates naturally present in the experiment.
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Affiliation(s)
- Katalin Gillemot
- Department of Physics, Lancaster University, Lancaster, LA1 4YB, UK
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33
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Evangeli C, Gillemot K, Leary E, González MT, Rubio-Bollinger G, Lambert CJ, Agraït N. Engineering the thermopower of C60 molecular junctions. Nano Lett 2013; 13:2141-5. [PMID: 23544957 DOI: 10.1021/nl400579g] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We report the measurement of conductance and thermopower of C60 molecular junctions using a scanning tunneling microscope (STM). In contrast to previous measurements, we use the imaging capability of the STM to determine precisely the number of molecules in the junction and measure thermopower and conductance continuously and simultaneously during formation and breaking of the molecular junction, achieving a complete characterization at the single-molecule level. We find that the thermopower of C60 dimers formed by trapping a C60 on the tip and contacting an isolated C60 almost doubles with respect to that of a single C60 and is among the highest values measured to date for organic materials. Density functional theory calculations show that the thermopower and the figure of merit continue increasing with the number of C60 molecules, demonstrating the enhancement of thermoelectric preformance by manipulation of intermolecular interactions.
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Affiliation(s)
- Charalambos Evangeli
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Madrid, Spain
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González MT, Díaz A, Leary E, García R, Herranz MÁ, Rubio-Bollinger G, Martín N, Agraït N. Stability of Single- and Few-Molecule Junctions of Conjugated Diamines. J Am Chem Soc 2013; 135:5420-6. [DOI: 10.1021/ja312392q] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- M. Teresa González
- Instituto Madrileño de
Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Ciudad Universitaria de Cantoblanco, E-28049 Madrid,
Spain
| | | | - Edmund Leary
- Instituto Madrileño de
Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Ciudad Universitaria de Cantoblanco, E-28049 Madrid,
Spain
| | - Raúl García
- Departamento de Química
Orgánica, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - M. Ángeles Herranz
- Departamento de Química
Orgánica, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | | | - Nazario Martín
- Instituto Madrileño de
Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Ciudad Universitaria de Cantoblanco, E-28049 Madrid,
Spain
- Departamento de Química
Orgánica, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Nicolás Agraït
- Instituto Madrileño de
Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Ciudad Universitaria de Cantoblanco, E-28049 Madrid,
Spain
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35
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Castellanos-Gomez A, Cappelluti E, Roldán R, Agraït N, Guinea F, Rubio-Bollinger G. Electric-field screening in atomically thin layers of MoS₂: the role of interlayer coupling. Adv Mater 2013; 25:899-903. [PMID: 23118009 DOI: 10.1002/adma.201203731] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Indexed: 05/25/2023]
Affiliation(s)
- Andres Castellanos-Gomez
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands.
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36
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Castellanos-Gomez A, Rubio-Bollinger G, Garnica M, Barja S, Vázquez de Parga AL, Miranda R, Agraït N. Highly reproducible low temperature scanning tunneling microscopy and spectroscopy with in situ prepared tips. Ultramicroscopy 2012; 122:1-5. [PMID: 22955323 DOI: 10.1016/j.ultramic.2012.07.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Revised: 07/05/2012] [Accepted: 07/17/2012] [Indexed: 11/15/2022]
Affiliation(s)
- Andres Castellanos-Gomez
- Departamento de Física de la Materia Condensada (C-III), Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049 Madrid, Spain.
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Rubio-Bollinger G, Castellanos-Gomez A, Bilan S, Zotti LA, Arroyo CR, Agraït N, Cuevas JC. Carbon-fiber tips for scanning probe microscopes and molecular electronics experiments. Nanoscale Res Lett 2012; 7:254. [PMID: 22587692 PMCID: PMC3431272 DOI: 10.1186/1556-276x-7-254] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 05/15/2012] [Indexed: 05/31/2023]
Abstract
We fabricate and characterize carbon-fiber tips for their use in combined scanning tunneling and force microscopy based on piezoelectric quartz tuning fork force sensors. An electrochemical fabrication procedure to etch the tips is used to yield reproducible sub-100-nm apex. We also study electron transport through single-molecule junctions formed by a single octanethiol molecule bonded by the thiol anchoring group to a gold electrode and linked to a carbon tip by the methyl group. We observe the presence of conductance plateaus during the stretching of the molecular bridge, which is the signature of the formation of a molecular junction.
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Affiliation(s)
- Gabino Rubio-Bollinger
- Departamento de Física de la Materia Condensada (C–III), Universidad Autónoma de Madrid, Campus de Cantoblanco, Madrid, E-28049, Spain
| | - Andres Castellanos-Gomez
- Departamento de Física de la Materia Condensada (C–III), Universidad Autónoma de Madrid, Campus de Cantoblanco, Madrid, E-28049, Spain
- Kavli Institute of Nanoscience, 5046 Delft University of Technology, Delft, 2600, GA, Netherlands
| | - Stefan Bilan
- Departamento de Física Teórica de la Materia Condensada (C–III), Universidad Autónoma de Madrid, Campus de Cantoblanco, Madrid, E-28049, Spain
| | - Linda A Zotti
- Departamento de Física Teórica de la Materia Condensada (C–III), Universidad Autónoma de Madrid, Campus de Cantoblanco, Madrid, E-28049, Spain
| | - Carlos R Arroyo
- Departamento de Física de la Materia Condensada (C–III), Universidad Autónoma de Madrid, Campus de Cantoblanco, Madrid, E-28049, Spain
- Kavli Institute of Nanoscience, 5046 Delft University of Technology, Delft, 2600, GA, Netherlands
| | - Nicolás Agraït
- Departamento de Física de la Materia Condensada (C–III), Universidad Autónoma de Madrid, Campus de Cantoblanco, Madrid, E-28049, Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia IMDEA-Nanociencia, Madrid, E-28049, Spain
| | - Juan Carlos Cuevas
- Departamento de Física Teórica de la Materia Condensada (C–III), Universidad Autónoma de Madrid, Campus de Cantoblanco, Madrid, E-28049, Spain
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38
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Castellanos-Gomez A, Poot M, Steele GA, van der Zant HSJ, Agraït N, Rubio-Bollinger G. Mechanical properties of freely suspended semiconducting graphene-like layers based on MoS2. Nanoscale Res Lett 2012; 7:233. [PMID: 22533903 PMCID: PMC3359267 DOI: 10.1186/1556-276x-7-233] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Accepted: 04/25/2012] [Indexed: 05/21/2023]
Abstract
We fabricate freely suspended nanosheets of molybdenum disulphide (MoS2) which are characterized by quantitative optical microscopy and high-resolution friction force microscopy. We study the elastic deformation of freely suspended nanosheets of MoS2 using an atomic force microscope. The Young's modulus and the initial pre-tension of the nanosheets are determined by performing a nanoscopic version of a bending test experiment. MoS2 sheets show high elasticity and an extremely high Young's modulus (0.30 TPa, 50% larger than steel). These results make them a potential alternative to graphene in applications requiring flexible semiconductor materials.PACS, 73.61.Le, other inorganic semiconductors, 68.65.Ac, multilayers, 62.20.de, elastic moduli, 81.40.Jj, elasticity and anelasticity, stress-strain relations.
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Affiliation(s)
- Andres Castellanos-Gomez
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, Delft 2628, CJ, The Netherlands
- Departamento de Física de la Materia Condensada (C-III), Universidad Autónoma de Madrid, Campus de Cantoblanco, Madrid E-28049, Spain
| | - Menno Poot
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, Delft 2628, CJ, The Netherlands
- Department of Engineering Science, Yale University, Becton 215, 15 Prospect St., New Haven, CT 06520, USA
| | - Gary A Steele
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, Delft 2628, CJ, The Netherlands
| | - Herre SJ van der Zant
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, Delft 2628, CJ, The Netherlands
| | - Nicolás Agraït
- Departamento de Física de la Materia Condensada (C-III), Universidad Autónoma de Madrid, Campus de Cantoblanco, Madrid E-28049, Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Madrid E-28049, Spain
| | - Gabino Rubio-Bollinger
- Departamento de Física de la Materia Condensada (C-III), Universidad Autónoma de Madrid, Campus de Cantoblanco, Madrid E-28049, Spain
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39
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Castellanos-Gomez A, Arroyo CR, Agraït N, Rubio-Bollinger G. Calibration of piezoelectric positioning actuators using a reference voltage-to-displacement transducer based on quartz tuning forks. Microsc Microanal 2012; 18:353-358. [PMID: 22436334 DOI: 10.1017/s1431927611012839] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We use a piezoelectric quartz tuning fork to calibrate the displacement of ceramic piezoelectric scanners that are widely employed in scanning probe microscopy. We measure the static piezoelectric response of a quartz tuning fork and find it to be highly linear, nonhysteretic and with negligible creep. These performance characteristics, close to those of an ideal transducer, make quartz transducers superior to ceramic piezoelectric actuators. Furthermore, quartz actuators in the form of a tuning fork have the advantage of yielding static displacements comparable to those of local probe microscope scanners. We use the static displacement of a quartz tuning fork as a reference to calibrate the three axis displacement of a ceramic piezoelectric scanner. Although this calibration technique is a nontraceable method, it can be more versatile than using calibration grids because it enables characterization of the linear and nonlinear response of a piezoelectric scanner in a broad range of displacements, spanning from a fraction of a nanometer to hundreds of nanometers. In addition, the creep and the speed dependent piezoelectric response of ceramic scanners can be studied in detail.
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Affiliation(s)
- Andres Castellanos-Gomez
- Departamento de Física de la Materia Condensada (C-III), Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049 Madrid, Spain
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Castellanos-Gomez A, Poot M, Steele GA, van der Zant HSJ, Agraït N, Rubio-Bollinger G. Elastic properties of freely suspended MoS2 nanosheets. Adv Mater 2012; 24:772-5. [PMID: 22231284 DOI: 10.1002/adma.201103965] [Citation(s) in RCA: 372] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2012] [Indexed: 05/21/2023]
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Castellanos-Gomez A, Wojtaszek M, Tombros N, Agraït N, van Wees BJ, Rubio-Bollinger G. Atomically thin mica flakes and their application as ultrathin insulating substrates for graphene. Small 2011; 7:2491-7. [PMID: 21805626 DOI: 10.1002/smll.201100733] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Indexed: 05/22/2023]
Abstract
By mechanical exfoliation, it is possible to deposit atomically thin mica flakes down to single-monolayer thickness on SiO2/Si wafers. The optical contrast of these mica flakes on top of a SiO2/Si substrate depends on their thickness, the illumination wavelength, and the SiO2 substrate thickness, and can be quantitatively accounted for by a Fresnel-law-based model. The preparation of atomically thin insulating crystalline sheets will enable the fabrication of ultrathin, defect-free insulating substrates, dielectric barriers, or planar electron-tunneling junctions. Additionally, it is shown that few-layer graphene flakes can be deposited on top of a previously transferred mica flake. Our transfer method relies on viscoelastic stamps, as used for soft lithography. A Raman spectroscopy study shows that such an all-dry deposition technique yields cleaner and higher-quality flakes than conventional wet-transfer procedures based on lithographic resists.
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Affiliation(s)
- Andres Castellanos-Gomez
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Campus de Cantoblanco, E-28049 Madrid, Spain; Physics of Nanodevices, Zernike Institute for Advanced Materials, University of Groningen, The Netherlands.
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42
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Arroyo CR, Leary E, Castellanos-Gómez A, Rubio-Bollinger G, González MT, Agraït N. Influence of Binding Groups on Molecular Junction Formation. J Am Chem Soc 2011; 133:14313-9. [DOI: 10.1021/ja201861k] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
| | - Edmund Leary
- Instituto Madrileño de Estudios Advanzados en Nanociencia (IMDEA-Nanociencia), Ciudad Universitaria de Cantoblanco, E-28049 Madrid, Spain
| | | | | | - M. Teresa González
- Instituto Madrileño de Estudios Advanzados en Nanociencia (IMDEA-Nanociencia), Ciudad Universitaria de Cantoblanco, E-28049 Madrid, Spain
| | - Nicolás Agraït
- Instituto Madrileño de Estudios Advanzados en Nanociencia (IMDEA-Nanociencia), Ciudad Universitaria de Cantoblanco, E-28049 Madrid, Spain
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Leary E, González MT, van der Pol C, Bryce MR, Filippone S, Martín N, Rubio-Bollinger G, Agraït N. Unambiguous one-molecule conductance measurements under ambient conditions. Nano Lett 2011; 11:2236-2241. [PMID: 21548597 DOI: 10.1021/nl200294s] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
One of the challenging goals of molecular electronics is to wire exactly one molecule between two electrodes. This is generally nontrivial under ambient conditions. We describe a new and straightforward protocol for unambiguously isolating a single organic molecule on a metal surface and wiring it inside a nanojunction under ambient conditions. Our strategy employs C(60) terminal groups which act as molecular beacons allowing molecules to be visualized and individually targeted on a gold surface using an scanning tunneling microscope. After isolating one molecule, we then use the C(60) groups as alligator clips to wire it between the tip and surface. Once wired, we can monitor how the conductance of a purely one molecule junction evolves with time, stretch the molecule in the junction, observing characteristic current plateaus upon elongation, and also perform direct I-V spectroscopy. By characterizing and controlling the junction, we can draw stronger conclusions about the observed variation in molecular conductance than was previously possible.
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Affiliation(s)
- Edmund Leary
- Instituto Madrileño de Estudios Avanzados, Facultad de Ciencias Módulo 9, 3a planta Avda. Fco. Tomás y Valiente, 7 Ciudad Universitaria de Cantoblanco, 28049, Madrid, Spain.
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44
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Castellanos-Gomez A, Agraït N, Rubio-Bollinger G. Carbon fibre tips for scanning probe microscopy based on quartz tuning fork force sensors. Nanotechnology 2010; 21:145702. [PMID: 20220220 DOI: 10.1088/0957-4484/21/14/145702] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We report the fabrication and the characterization of carbon fibre tips for use in combined scanning tunnelling and force microscopy based on piezoelectric quartz tuning fork force sensors. We find that the use of carbon fibre tips results in a minimum impact on the dynamics of quartz tuning fork force sensors, yielding a high quality factor and, consequently, a high force gradient sensitivity. This high force sensitivity, in combination with high electrical conductivity and oxidation resistance of carbon fibre tips, make them very convenient for combined and simultaneous scanning tunnelling microscopy and atomic force microscopy measurements. Interestingly, these tips are quite robust against occasionally occurring tip crashes. An electrochemical fabrication procedure to etch the tips is presented that produces a sub-100-nm apex radius in a reproducible way which can yield high resolution images.
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Affiliation(s)
- A Castellanos-Gomez
- Departamento de Física de la Materia Condensada (C-III), Universidad Autónoma de Madrid, Campus de Cantoblanco, Madrid, Spain
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45
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Abstract
We have performed an experimental characterization of the dynamics of oscillating quartz tuning forks which are being increasingly used in scanning probe microscopy as force sensors. We show that tuning forks can be described as a system of coupled oscillators. Nevertheless, this description requires knowledge of the elastic coupling constant between the prongs of the tuning fork, which has not yet been measured. Therefore, tuning forks have usually been described within the single oscillator or the weakly coupled oscillators approximation that neglects the coupling between the prongs. We propose three different procedures to measure the elastic coupling constant: an opto-mechanical method, a variation of the Cleveland method and a thermal noise based method. We find that the coupling between the quartz tuning fork prongs has a strong influence on the dynamics and the measured motion is in remarkable agreement with a simple model of coupled harmonic oscillators. The precise determination of the elastic coupling between the prongs of a tuning fork allows us to obtain a quantitative relation between the resonance frequency shift and the force gradient acting at the free end of a tuning fork prong.
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Affiliation(s)
- A Castellanos-Gomez
- Departamento de Física de la Materia Condensada (C-III), Universidad Autónoma de Madrid, Madrid, Spain
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Moreno-Moreno M, Castellanos-Gomez A, Rubio-Bollinger G, Gomez-Herrero J, Agraït N. Ultralong natural graphene nanoribbons and their electrical conductivity. Small 2009; 5:924-927. [PMID: 19242945 DOI: 10.1002/smll.200801442] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Affiliation(s)
- Miriam Moreno-Moreno
- Departamento de Física de la Materia Condensada (C-III), Universidad Autónoma de Madrid, Madrid, Spain
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Hihath J, Arroyo CR, Rubio-Bollinger G, Tao N, Agraït N. Study of electron-phonon interactions in a single molecule covalently connected to two electrodes. Nano Lett 2008; 8:1673-1678. [PMID: 18457456 DOI: 10.1021/nl080580e] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Presented here is a study of electron-phonon interactions in a single molecule junction where the molecule is covalently connected to two electrodes. In this system, vibration modes in a single molecule junction are measured by sweeping the bias voltage between the two electrodes and recording the differential conductance while the strain in the junction is changed by separating the two electrodes. This unique approach allows changes in conductance to be compared to changes in the configuration of a single molecule junction. This system opens a new door for characterizing single molecule junctions and a better understanding of the relationship between molecular conductance, electron-phonon interactions, and configuration.
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Affiliation(s)
- Joshua Hihath
- Department of Electrical Engineering, Center for Solid State Electronics, Arizona State University, Tempe, AZ 85287-5706, USA
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Smit RHM, Grande R, Lasanta B, Riquelme JJ, Rubio-Bollinger G, Agraït N. A low temperature scanning tunneling microscope for electronic and force spectroscopy. Rev Sci Instrum 2007; 78:113705. [PMID: 18052478 DOI: 10.1063/1.2804165] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
In this article, we describe and test a novel way to extend a low temperature scanning tunneling microscope with the capability to measure forces. The tuning fork that we use for this is optimized to have a high quality factor and frequency resolution. Moreover, as this technique is fully compatible with the use of bulk tips, it is possible to combine the force measurements with the use of superconductive or magnetic tips, advantageous for electronic spectroscopy. It also allows us to calibrate both the amplitude and the spring constant of the tuning fork easily, in situ and with high precision.
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Affiliation(s)
- R H M Smit
- Laboratorio de Bajas Temperaturas, Departamento Física de la Materia Condensada C-III, Universidad Autónoma de Madrid, E-28049 Madrid, Spain.
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Abstract
We report high resolution simultaneous measurements of electrical conductance and force gradient between two sharp gold tips as their separation is varied from the tunneling distance to atomic-size contact. The use of atomically sharp tips minimizes van der Waals interaction, making it possible to identify the short-range metallic adhesion contribution to the total force.
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Affiliation(s)
- G Rubio-Bollinger
- Laboratorio de Bajas Temperaturas, Department Física de la Materia Condensada C-III, Instituto Universitario de Ciencia de Materiales Nicolás Cabrera, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
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Agraït N, Untiedt C, Rubio-Bollinger G, Vieira S. Onset of energy dissipation in ballistic atomic wires. Phys Rev Lett 2002; 88:216803. [PMID: 12059491 DOI: 10.1103/physrevlett.88.216803] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2001] [Indexed: 05/23/2023]
Abstract
Electronic transport at finite voltages in free-standing gold atomic chains of up to seven atoms in length is studied at low temperatures using a scanning tunneling microscope. The conductance vs voltage curves show that transport in these single-mode ballistic atomic wires is nondissipative up to a finite voltage threshold of the order of several mV. The onset of dissipation and resistance within the wire corresponds to the excitation of the atomic vibrations by the electrons traversing the wire and is very sensitive to strain.
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Affiliation(s)
- Nicolás Agraït
- Laboratorio de Bajas Temperaturas, Departamento de Física de la Materia Condensada C-III, and Instituto Universitario de Ciencia de Materiales Nicolás Cabrera, Universidad Autónoma de Madrid, E-28049 Madrid, Spain.
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