1
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Vázquez H. Toward Density-Functional Theory-Based Structure-Conductance Relationships in Single Molecule Junctions. J Phys Chem Lett 2022; 13:9326-9331. [PMID: 36178209 DOI: 10.1021/acs.jpclett.2c02349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
A method is presented that allows for the calculation using density functional theory (DFT) of the tunneling conductance of single molecule junctions for thousands of junction structures. With a single scaling parameter, conductance is evaluated from clusters consisting of the molecule bonded to one Au atom at each end. Junction geometries are obtained without any constraints from ab initio molecular dynamics simulations at room temperature. This method accurately reproduces standard DFT-based conductance values for several molecular and electrode structures while reducing the computational cost by a factor of ∼400×, allowing for the conductance of tens of thousands of geometries to be computed. When applied to a pair of conjugated molecules, these large data sets quantify the effect on conductance of molecular structure or quantum chemical properties. This methodology enables reliable DFT-based conductance calculations at a negligible computational cost and opens the way to quantitative structure-conductance relationships.
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Affiliation(s)
- Héctor Vázquez
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, PragueCZ-162 00, Czech Republic
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2
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Arasu NP, Vázquez H. Development of Classical Force Fields for Interfaces between Single Molecules and Au. J Phys Chem A 2022; 126:5031-5039. [PMID: 35880700 DOI: 10.1021/acs.jpca.2c02514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Interfaces between metals and organic materials play an essential role in molecular surface science, photovoltaics, or molecular electronics. Modeling the evolution of interface geometry over sufficiently long timescales requires an accurate parameterization of the relevant metal-molecule interactions. Here, we describe a method for calculating interface parameters from reference density functional theory calculations of small metal-molecule complexes. We apply this method to develop a parameter set for a series of metal-molecule-metal junctions. We study the dynamics of short oligophenyls with amine, methyl-sulfide, or direct Au-C links, which are bonded to Au(111) via small adatom structures. Nanosecond classical molecular dynamics simulations using the generated parameter set reveal insight into molecular degrees of freedom not accessible from ab initio molecular dynamics simulations.
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Affiliation(s)
- Narendra P Arasu
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, 162 00 Prague, Czech Republic.,Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague, Czech Republic
| | - Héctor Vázquez
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, 162 00 Prague, Czech Republic
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3
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Lo KC, Hau KI, Chan WK. Photoconductivity enhancement and charge transport properties in ruthenium-containing block copolymer/carbon nanotube hybrids. NANOSCALE 2018; 10:6474-6486. [PMID: 29569662 DOI: 10.1039/c7nr09670d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Functional polymer/carbon nanotube (CNT) hybrid materials can serve as a good model for light harvesting systems based on CNTs. This paper presents the synthesis of block copolymer/CNT hybrids and the characterization of their photocurrent responses by both experimental and computational approaches. A series of functional diblock copolymers was synthesized by reversible addition-fragmentation chain transfer polymerizations for the dispersion and functionalization of CNTs. The block copolymers contain photosensitizing ruthenium complexes and modified pyrene-based anchoring units. The photocurrent responses of the polymer/CNT hybrids were measured by photoconductive atomic force microscopy (PCAFM), from which the experimental data were analyzed by vigorous statistical models. The difference in photocurrent response among different hybrids was correlated to the conformations of the hybrids, which were elucidated by molecular dynamics simulations, and the electronic properties of polymers. The photoresponse of the block copolymer/CNT hybrids can be enhanced by introducing an electron-accepting block between the photosensitizing block and the CNT. We have demonstrated that the application of a rigorous statistical methodology can unravel the charge transport properties of these hybrid materials and provide general guidelines for the design of molecular light harvesting systems.
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Affiliation(s)
- Kin Cheung Lo
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong.
| | - King In Hau
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong.
| | - Wai Kin Chan
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong.
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4
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Trasobares J, Rech J, Jonckheere T, Martin T, Aleveque O, Levillain E, Diez-Cabanes V, Olivier Y, Cornil J, Nys JP, Sivakumarasamy R, Smaali K, Leclere P, Fujiwara A, Théron D, Vuillaume D, Clément N. Estimation of π-π Electronic Couplings from Current Measurements. NANO LETTERS 2017; 17:3215-3224. [PMID: 28358215 DOI: 10.1021/acs.nanolett.7b00804] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The π-π interactions between organic molecules are among the most important parameters for optimizing the transport and optical properties of organic transistors, light-emitting diodes, and (bio-) molecular devices. Despite substantial theoretical progress, direct experimental measurement of the π-π electronic coupling energy parameter t has remained an old challenge due to molecular structural variability and the large number of parameters that affect the charge transport. Here, we propose a study of π-π interactions from electrochemical and current measurements on a large array of ferrocene-thiolated gold nanocrystals. We confirm the theoretical prediction that t can be assessed from a statistical analysis of current histograms. The extracted value of t ≈35 meV is in the expected range based on our density functional theory analysis. Furthermore, the t distribution is not necessarily Gaussian and could be used as an ultrasensitive technique to assess intermolecular distance fluctuation at the subangström level. The present work establishes a direct bridge between quantum chemistry, electrochemistry, organic electronics, and mesoscopic physics, all of which were used to discuss results and perspectives in a quantitative manner.
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Affiliation(s)
- J Trasobares
- Institute of Electronics, Microelectronics and Nanotechnology, CNRS, University of Lille , Avenue Poincaré, BP60069, 59652, Villeneuve d'Ascq France
| | - J Rech
- Aix Marseille University, Universite de Toulon, CNRS, CPT , 163 Avenue de Luminy, 13288 Marseille cedex 9, France
| | - T Jonckheere
- Aix Marseille University, Universite de Toulon, CNRS, CPT , 163 Avenue de Luminy, 13288 Marseille cedex 9, France
| | - T Martin
- Aix Marseille University, Universite de Toulon, CNRS, CPT , 163 Avenue de Luminy, 13288 Marseille cedex 9, France
| | - O Aleveque
- Université d'Angers, CNRS UMR 6200, Laboratoire MOLTECH-Anjou , 2 bd Lavoisier, 49045 Angers cedex, France
| | - E Levillain
- Université d'Angers, CNRS UMR 6200, Laboratoire MOLTECH-Anjou , 2 bd Lavoisier, 49045 Angers cedex, France
| | - V Diez-Cabanes
- Laboratory for Chemistry of Novel Materials, University of Mons , Place du Parc 20, B-7000 Mons, Belgium
| | - Y Olivier
- Laboratory for Chemistry of Novel Materials, University of Mons , Place du Parc 20, B-7000 Mons, Belgium
| | - J Cornil
- Laboratory for Chemistry of Novel Materials, University of Mons , Place du Parc 20, B-7000 Mons, Belgium
| | - J P Nys
- Institute of Electronics, Microelectronics and Nanotechnology, CNRS, University of Lille , Avenue Poincaré, BP60069, 59652, Villeneuve d'Ascq France
| | - R Sivakumarasamy
- Institute of Electronics, Microelectronics and Nanotechnology, CNRS, University of Lille , Avenue Poincaré, BP60069, 59652, Villeneuve d'Ascq France
| | - K Smaali
- Institute of Electronics, Microelectronics and Nanotechnology, CNRS, University of Lille , Avenue Poincaré, BP60069, 59652, Villeneuve d'Ascq France
| | - P Leclere
- Laboratory for Chemistry of Novel Materials, University of Mons , Place du Parc 20, B-7000 Mons, Belgium
| | - A Fujiwara
- NTT Basic Research Laboratories, 3-1, Morinosato Wakamiya, Atsugi-shi, kanagawa 243-0198, Japan
| | - D Théron
- Institute of Electronics, Microelectronics and Nanotechnology, CNRS, University of Lille , Avenue Poincaré, BP60069, 59652, Villeneuve d'Ascq France
| | - D Vuillaume
- Institute of Electronics, Microelectronics and Nanotechnology, CNRS, University of Lille , Avenue Poincaré, BP60069, 59652, Villeneuve d'Ascq France
| | - N Clément
- Institute of Electronics, Microelectronics and Nanotechnology, CNRS, University of Lille , Avenue Poincaré, BP60069, 59652, Villeneuve d'Ascq France
- NTT Basic Research Laboratories, 3-1, Morinosato Wakamiya, Atsugi-shi, kanagawa 243-0198, Japan
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5
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Carey R, Chen L, Gu B, Franco I. When can time-dependent currents be reproduced by the Landauer steady-state approximation? J Chem Phys 2017; 146:174101. [DOI: 10.1063/1.4981915] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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6
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Tschudi SE, Reuter MG. Estimating the Landauer-Büttiker transmission function from single molecule break junction experiments. NANOTECHNOLOGY 2016; 27:425203. [PMID: 27623441 DOI: 10.1088/0957-4484/27/42/425203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
When investigating the electronic response properties of molecules, experiments often measure conductance whereas computation predicts the transmission probability. Although Landauer-Büttiker theory usually relates the two, comparison between experiment and computation remains difficult because experimental data (specifically those from break junctions) are statistical and computational results are deterministic. In this work we develop tools to quantitatively estimate-with error bars-the shape of the Landauer-Büttiker transmission function directly from experimental statistics on conductance and thermopower (if the latter is also available). We subsequently apply these tools to existing data, demonstrating a rigorous statistical comparison between experimental and computational results on molecular electron transport.
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Affiliation(s)
- Stephen E Tschudi
- Department of Applied Mathematics & Statistics and Institute for Advanced Computational Science, Stony Brook University, Stony Brook, NY 11794, USA
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7
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Pejov L, Petreska I, Kocarev L. Designing field-controllable graphene-dot-graphene single molecule switches: A quantum-theoretical proof-of-concept under realistic operating conditions. J Chem Phys 2015; 143:244704. [PMID: 26723699 DOI: 10.1063/1.4937411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A theoretical proof of the concept that a particularly designed graphene-based moletronics device, constituted by two semi-infinite graphene subunits, acting as source and drain electrodes, and a central benzenoid ring rotator (a "quantum dot"), could act as a field-controllable molecular switch is outlined and analyzed with the density functional theory approach. Besides the ideal (0 K) case, we also consider the operation of such a device under realistic operating (i.e., finite-temperature) conditions. An in-depth insight into the physics behind device controllability by an external field was gained by thorough analyses of the torsional potential of the dot under various conditions (absence or presence of an external gating field with varying strength), computing the torsional correlation time and transition probabilities within the Bloembergen-Purcell-Pound formalism. Both classical and quantum mechanical tunneling contributions to the intramolecular rotation were considered in the model. The main idea that we put forward in the present study is that intramolecular rotors can be controlled by the gating field even in cases when these groups do not possess a permanent dipole moment (as in cases considered previously by us [I. Petreska et al., J. Chem. Phys. 134, 014708-1-014708-12 (2011)] and also by other groups [P. E. Kornilovitch et al., Phys. Rev. B 66, 245413-1-245413-7 (2002)]). Consequently, one can control the molecular switching properties by an external electrostatic field utilizing even nonpolar intramolecular rotors (i.e., in a more general case than those considered so far). Molecular admittance of the currently considered graphene-based molecular switch under various conditions is analyzed employing non-equilibrium Green's function formalism, as well as by analysis of frontier molecular orbitals' behavior.
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Affiliation(s)
- Ljupčo Pejov
- Department of Physical Chemistry, Institute of Chemistry, SS. Cyril and Methodius University, Arhimedova 5, P.O. Box 162, 1001 Skopje, Republic of Macedonia
| | - Irina Petreska
- Institute of Physics, Faculty of Natural Sciences and Mathematics, SS. Cyril and Methodius University, P.O. Box 162, 1001 Skopje, Republic of Macedonia
| | - Ljupčo Kocarev
- Macedonian Academy of Sciences and Arts, Krste Misirkov 2, P.O. Box 428, 1000 Skopje, Republic of Macedonia
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8
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Quan R, Pitler CS, Ratner MA, Reuter MG. Quantitative Interpretations of Break Junction Conductance Histograms in Molecular Electron Transport. ACS NANO 2015; 9:7704-7713. [PMID: 26168212 DOI: 10.1021/acsnano.5b03183] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We develop theoretical and computational tools for extracting quantitative molecular information from experimental conductance histograms for electron transport through single-molecule break junctions. These experimental setups always measure a combination of molecular conductance and direct electrode-electrode tunneling; our derivations explicitly incorporate the effects of such background tunneling. Validation of our models to simulated data shows that background tunneling is crucial for quantitative analyses (even in cases where it appears to be qualitatively negligible), and comparison to experimental data is favorable. Finally, we generalize these ideas to the case of molecules with a destructive interference feature and discuss potential signatures for interference in a conductance histogram.
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9
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Popescu B, Rahman H, Kleinekathöfer U. Using the Chebychev expansion in quantum transport calculations. J Chem Phys 2015; 142:154103. [PMID: 25903862 DOI: 10.1063/1.4917198] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Irradiation by laser pulses and a fluctuating surrounding liquid environment can, for example, lead to time-dependent effects in the transport through molecular junctions. From the theoretical point of view, time-dependent theories of quantum transport are still challenging. In one of these existing transport theories, the energy-dependent coupling between molecule and leads is decomposed into Lorentzian functions. This trick has successfully been combined with quantum master approaches, hierarchical formalisms, and non-equilibrium Green's functions. The drawback of this approach is, however, its serious limitation to certain forms of the molecule-lead coupling and to higher temperatures. Tian and Chen [J. Chem. Phys. 137, 204114 (2012)] recently employed a Chebychev expansion to circumvent some of these latter problems. Here, we report on a similar approach also based on the Chebychev expansion but leading to a different set of coupled differential equations using the fact that a derivative of a zeroth-order Bessel function can again be given in terms of Bessel functions. Test calculations show the excellent numerical accuracy and stability of the presented formalism. The time span for which this Chebychev expansion scheme is valid without any restrictions on the form of the spectral density or temperature can be determined a priori.
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Affiliation(s)
- Bogdan Popescu
- Department of Physics and Earth Sciences, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
| | - Hasan Rahman
- Department of Physics and Earth Sciences, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
| | - Ulrich Kleinekathöfer
- Department of Physics and Earth Sciences, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
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10
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Berritta M, Manrique DZ, Lambert CJ. Interplay between quantum interference and conformational fluctuations in single-molecule break junctions. NANOSCALE 2015; 7:1096-1101. [PMID: 25479372 DOI: 10.1039/c4nr05316h] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We theoretically explored the combined role of conformational fluctuations and quantum interference in determining the electrical conductance of single-molecule break junctions. In particular we computed the conductance of a family of methylsulfide-functionalized trans-α,ω-diphenyloligoene molecules, with terminal phenyl rings containing meta or para linkages, for which (at least in the absence of fluctuations) destructive interference in the former is expected to decrease their electrical conductance compared with the latter. We compared the predictions of density functional theory (DFT), in which fluctuational effects are absent, with results for the conformationally-averaged conductance obtained from an ensemble of conformations obtained from classical molecular dynamics. We found that junctions formed from these molecules exhibit distinct transport regimes during junction evolution and the signatures of quantum interference in these molecules survive the effect of conformational fluctuations. Furthermore, the agreement between theory and experiment is significantly improved by including conformational averaging.
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Affiliation(s)
- Marco Berritta
- Department of Physics and Astronomy, Uppsala University, Box 516, S-75120 Uppsala, Sweden
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11
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Abstract
The conductivity of DNA in molecular junctions is often probed experimentally under dry conditions, but it is unclear how much of the solvent remains attached to the DNA and how this impacts its structure, electronic states, and conductivity. Classical MD simulations show that DNA is unstable if the solvent is removed completely, while a micro-hydrated system with few water molecules shows similar charge transport properties as fully solvated DNA does. This surprising effect is analyzed in detail by mapping the density functional theory-based electronic structure to a tight-binding Hamiltonian, allowing for an estimate of conductivity of various DNA sequences with snapshot-averaged Landauer's approach. The characteristics of DNA charge transport turn out to be determined by the nearest hydration shell(s), and the removal of bulk solvent has little effect on the transport.
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Affiliation(s)
- Mario Wolter
- Institute of Physical Chemistry, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
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12
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Yimer YY, Jha KC, Tsige M. Epitaxial transfer through end-group coordination modulates the odd-even effect in an alkanethiol monolayer assembly. NANOSCALE 2014; 6:3496-3502. [PMID: 24553572 DOI: 10.1039/c3nr05671f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Short spacer length and high end-group coordination lead to the top network acting as a template for the buried sulfur-gold interface of n-alkanethiols (SH-(CH2)n-OH or SH-(CH2)n-CH3) on gold {111}. Annealing and templating both drive toward a higher sampling of the spatially favorable bridge adsorption sites. The hydrogen-bonded network increases in strength by increasing the number of hydrogens participating per oxygen, from 1.75 to 1.98 for n = 14-30. Higher n leads to better packing (five times for hydroxyl-terminated and seven times for methyl-terminated for n = 14-30) and stability of monolayers, while lower n results in better epitaxial transfer (transfer coefficient ratio = 13.5 for {SH-(CH2)14-OH}/{SH-(CH2)30-CH3}) and actuation. Odd values of n for the hydroxyl-terminated n-alkanethiols lead to lattice spacing of an average of 0.04 ± 0.01 Å higher than even values. There is a structural transition in properties around spacer length n = 24-27. Characterization of monolayer assembly through correlation between adatom and network layers provides recursive design principles for actuation and sensing applications.
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Affiliation(s)
- Yeneneh Y Yimer
- Department of Polymer Science, The University of Akron, Akron, Ohio 44325, USA.
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13
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French WR, Iacovella CR, Rungger I, Souza AM, Sanvito S, Cummings PT. Structural Origins of Conductance Fluctuations in Gold-Thiolate Molecular Transport Junctions. J Phys Chem Lett 2013; 4:887-91. [PMID: 26291351 DOI: 10.1021/jz4001104] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We report detailed atomistic simulations combined with high-fidelity conductance calculations to probe the structural origins of conductance fluctuations in thermally evolving Au-benzene-1,4-dithiolate-Au junctions. We compare the behavior of structurally ideal junctions (where the electrodes are modeled as flat surfaces) to structurally realistic, experimentally representative junctions resulting from break-junction simulations. The enhanced mobility of metal atoms in structurally realistic junctions results in significant changes to the magnitude and origin of the conductance fluctuations. Fluctuations are larger by a factor of 2-3 in realistic junctions compared to ideal junctions. Moreover, in junctions with highly deformed electrodes, the conductance fluctuations arise primarily from changes in the Au geometry, in contrast to results for junctions with nondeformed electrodes, where the conductance fluctuations are dominated by changes in the molecule geometry. These results provide important guidance to experimentalists developing strategies to control molecular conductance, and also to theoreticians invoking simplified structural models of junctions to predict their behavior.
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Affiliation(s)
- William R French
- †Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Christopher R Iacovella
- †Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Ivan Rungger
- ‡School of Physics and CRANN, Trinity College, Dublin 2, Ireland
| | | | - Stefano Sanvito
- ‡School of Physics and CRANN, Trinity College, Dublin 2, Ireland
| | - Peter T Cummings
- †Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
- §Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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14
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Conformation-dependent conductance through a molecular break junction. J Mol Model 2013; 19:4173-80. [PMID: 23440404 DOI: 10.1007/s00894-013-1794-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2012] [Accepted: 02/05/2013] [Indexed: 11/27/2022]
Abstract
Ab initio molecular dynamics simulations have been performed of a gold-1,4-benzenedithiol (BDT)-gold nanojunction under mechanical stress. For three different pulling rates between 10 and 40 m s(-1), it is found that the nanowire always ruptures between the second and third Au atom from the thiol sulfur. Larger rupture forces and longer extensions are required at higher pulling rates and vice versa. The electrical conductance was calculated along a pulling trajectory using the DFT-NEGF method to study the effect of thermal and stress-induced structural changes on the electrical transport properties. While the mechanically induced stretching of the junction is seen to lower the time-averaged conductance, thermal conformational changes are capable of altering the conductance by one order of magnitude. No single geometric quantity could be identified as the main contributor to the conductance fluctuations. Small modulations, however, can be explained in terms of C=C double bond vibrations in the BDT molecule. The dependence of the conductance on different geometric variables has further been investigated systematically by performing constrained geometry optimizations along a number of angle and dihedral coordinates. The largest changes in the conductance are observed when the Au-S-C angle and the Au-S-C-C dihedral are simultaneously constrained.
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15
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George C, Szleifer I, Ratner M. Multiple-time-scale motion in molecularly linked nanoparticle arrays. ACS NANO 2013. [PMID: 23199199 DOI: 10.1021/nn303320w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
We explore the transport of electrons between electrodes that encase a two-dimensional array of metallic quantum dots linked by molecular bridges (such as α,ω alkaline dithiols). Because the molecules can move at finite temperatures, the entire transport structure comprising the quantum dots and the molecules is in dynamical motion while the charge is being transported. There are then several physical processes (physical excursions of molecules and quantum dots, electronic migration, ordinary vibrations), all of which influence electronic transport. Each can occur on a different time scale. It is therefore not appropriate to use standard approaches to this sort of electron transfer problem. Instead, we present a treatment in which three different theoretical approaches-kinetic Monte Carlo, classical molecular dynamics, and quantum transport-are all employed. In certain limits, some of the dynamical effects are unimportant. But in general, the transport seems to follow a sort of dynamic bond percolation picture, an approach originally introduced as formal models and later applied to polymer electrolytes. Different rate-determining steps occur in different limits. This approach offers a powerful scheme for dealing with multiple time scale transport problems, as will exist in many situations with several pathways through molecular arrays or even individual molecules that are dynamically disordered.
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Affiliation(s)
- Christopher George
- Department of Chemistry, Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois 60208, USA
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16
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McCreery RL, Yan H, Bergren AJ. A critical perspective on molecular electronic junctions: there is plenty of room in the middle. Phys Chem Chem Phys 2013; 15:1065-81. [DOI: 10.1039/c2cp43516k] [Citation(s) in RCA: 124] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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17
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Paz SA, Zoloff Michoff ME, Negre CFA, Olmos-Asar JA, Mariscal MM, Sánchez CG, Leiva EPM. Configurational Behavior and Conductance of Alkanedithiol Molecular Wires from Accelerated Dynamics Simulations. J Chem Theory Comput 2012; 8:4539-45. [PMID: 26605613 DOI: 10.1021/ct3007327] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An accelerated dynamics scheme is employed to sample the configurational space of a system consisting of an alkanedithiol molecule confined to the gap between a metal tip and a perfect metal surface. With this information and by means of nonequilibrium green functions techniques (NEGF), conductance calculations are performed. The present results show that even for this system, which is one of the most simple conceivable because of the perfectness of the surface, a complex behavior appears due to the occurrence of an unexpected tip-molecule-surface arrangement, where the insertion of one of the molecular ends into the tip-surface gap generates configurations with strongly enhanced conductance. Estimates are also made for the time required to generate the molecular junction, indicating that it should depend on the tip-surface distance, thus opening the way to new experiments in this direction.
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Affiliation(s)
- S Alexis Paz
- Departamento de Matemática y Física, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba , Córdoba
| | - Martin E Zoloff Michoff
- Departamento de Matemática y Física, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba , Córdoba
| | - Christian F A Negre
- Departamento de Matemática y Física, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba , Córdoba
| | - Jimena A Olmos-Asar
- Departamento de Matemática y Física, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba , Córdoba
| | - Marcelo M Mariscal
- Departamento de Matemática y Física, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba , Córdoba
| | - Cristián G Sánchez
- Departamento de Matemática y Física, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba , Córdoba
| | - Ezequiel P M Leiva
- Departamento de Matemática y Física, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba , Córdoba
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18
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Popescu B, Woiczikowski PB, Elstner M, Kleinekathöfer U. Time-dependent view of sequential transport through molecules with rapidly fluctuating bridges. PHYSICAL REVIEW LETTERS 2012; 109:176802. [PMID: 23215213 DOI: 10.1103/physrevlett.109.176802] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Indexed: 06/01/2023]
Abstract
Molecules in junctions often fluctuate considerably, especially when subject to the influence of solvent molecules. These fluctuations in site energies and couplings can be sampled, for example, by using molecular dynamics simulations, and can lead to incoherent effects in charge transport. To this end, a popular snapshot-averaged Landauer approach is compared to a time-dependent Green's function scheme. Since sequential transport dominates in systems with rapidly varying bridges, schemes not taking the time order of conformations into account, such as the Landauer approach, are inappropriate.
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Affiliation(s)
- Bogdan Popescu
- School of Engineering and Science, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
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19
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Reuter MG, Hersam MC, Seideman T, Ratner MA. Signatures of cooperative effects and transport mechanisms in conductance histograms. NANO LETTERS 2012; 12:2243-2248. [PMID: 22494042 DOI: 10.1021/nl204379j] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We present a computational investigation into the line shapes of peaks in conductance histograms, finding that they possess high information content. In particular, the histogram peak associated with conduction through a single molecule elucidates the electron transport mechanism and is generally well-described by beta distributions. A statistical analysis of the peak corresponding to conduction through two molecules reveals the presence of cooperative effects between the molecules and also provides insight into the underlying conduction channels. This work describes tools for extracting additional interpretations from experimental statistical data, helping us better understand electron transport processes.
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Affiliation(s)
- Matthew G Reuter
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA.
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21
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French WR, Iacovella CR, Cummings PT. Large-scale atomistic simulations of environmental effects on the formation and properties of molecular junctions. ACS NANO 2012; 6:2779-2789. [PMID: 22335340 DOI: 10.1021/nn300276m] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Using an updated simulation tool, we examine molecular junctions composed of benzene-1,4-dithiolate bonded between gold nanotips, focusing on the importance of environmental factors and interelectrode distance on the formation and structure of bridged molecules. We investigate the complex relationship between monolayer density and tip separation, finding that the formation of multimolecule junctions is favored at low monolayer density, while single-molecule junctions are favored at high density. We demonstrate that tip geometry and monolayer interactions, two factors that are often neglected in simulation, affect the bonding geometry and tilt angle of bridged molecules. We further show that the structures of bridged molecules at 298 and 77 K are similar.
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Affiliation(s)
- William R French
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37212, USA
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22
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Demir F, Kirczenow G. Identification of the atomic scale structures of the gold-thiol interfaces of molecular nanowires by inelastic tunneling spectroscopy. J Chem Phys 2012; 136:014703. [DOI: 10.1063/1.3671455] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
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23
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Franco I, Solomon GC, Schatz GC, Ratner MA. Tunneling Currents That Increase with Molecular Elongation. J Am Chem Soc 2011; 133:15714-20. [DOI: 10.1021/ja205908q] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Ignacio Franco
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Gemma C. Solomon
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
| | - George C. Schatz
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Mark A. Ratner
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, United States
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Venkatramani R, Keinan S, Balaeff A, Beratan DN. Nucleic Acid Charge Transfer: Black, White and Gray. Coord Chem Rev 2011; 255:635-648. [PMID: 21528017 PMCID: PMC3081592 DOI: 10.1016/j.ccr.2010.12.010] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Theoretical studies of charge transport in deoxyribonucleic acid (DNA) and peptide nucleic acid (PNA) indicate that structure and dynamics modulate the charge transfer rates, and that different members of a structural ensemble support different charge transport mechanisms. Here, we review the influences of nucleobase geometry, electronic structure, solvent environment, and thermal conformational fluctuations on the charge transfer mechanism. We describe an emerging framework for understanding the diversity of charge transport mechanisms seen in nucleic acids.
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Affiliation(s)
| | - Shahar Keinan
- Department of Chemistry, Duke University, Durham, North Carolina 27708
| | - Alexander Balaeff
- Department of Chemistry, Duke University, Durham, North Carolina 27708
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29
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Lin LL, Wang CK, Luo Y. Inelastic electron tunneling spectroscopy of gold-benzenedithiol-gold junctions: accurate determination of molecular conformation. ACS NANO 2011; 5:2257-63. [PMID: 21309567 DOI: 10.1021/nn103522k] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The gold-benzenedithiol-gold junction is the classic prototype of molecular electronics. However, even with the similar experimental setup, it has been difficult to reproduce the measured results because of the lack of basic information about the molecular confirmation inside the junction. We have performed systematic first principles study on the inelastic electron tunneling spectroscopy of this classic junction. By comparing the calculated spectra with four different experimental results, the most possible conformations of the molecule under different experimental conditions have been successfully determined. The relationship between the contact configuration and the resulted spectra is revealed. It demonstrates again that one should always combine the theoretical and experimental inelastic electron tunneling spectra to determine the molecular conformation in a junction. Our simulations have also suggested that in terms of the reproducibility and stability, the electromigrated nanogap technique is much better than the mechanically controllable break junction technique.
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Affiliation(s)
- Li-Li Lin
- College of Physics and Electronics, Shandong Normal University, Jinan 250014, PR China
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30
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Moore AM, Yeganeh S, Yao Y, Claridge SA, Tour JM, Ratner MA, Weiss PS. Polarizabilities of adsorbed and assembled molecules: measuring the conductance through buried contacts. ACS NANO 2010; 4:7630-6. [PMID: 21077677 PMCID: PMC3010874 DOI: 10.1021/nn102371z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2010] [Accepted: 11/03/2010] [Indexed: 05/22/2023]
Abstract
We have measured the polarizabilities of four families of molecules adsorbed to Au{111} surfaces, with structures ranging from fully saturated to fully conjugated, including single-molecule switches. Measured polarizabilities increase with increasing length and conjugation in the adsorbed molecules and are consistent with theoretical calculations. For single-molecule switches, the polarizability reflects the difference in substrate-molecule electronic coupling in the ON and OFF conductance states. Calculations suggest that the switch between the two conductance states is correlated with an oxidation state change in a nitro functional group in the switch molecules.
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Affiliation(s)
- Amanda M. Moore
- Departments of Chemistry and Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Sina Yeganeh
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Yuxing Yao
- Department of Chemistry and Smalley Institute for Nanoscale Science and Technology, Rice University, Houston, Texas 77005, United States
| | - Shelley A. Claridge
- California NanoSystems Institute and Departments of Chemistry & Biochemistry and Materials Science & Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - James M. Tour
- Department of Chemistry and Smalley Institute for Nanoscale Science and Technology, Rice University, Houston, Texas 77005, United States
- Address correspondence to , ,
| | - Mark A. Ratner
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, United States
- Address correspondence to , ,
| | - Paul S. Weiss
- Departments of Chemistry and Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- California NanoSystems Institute and Departments of Chemistry & Biochemistry and Materials Science & Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
- Address correspondence to , ,
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31
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Liu H, Chen X, Bu Y. Redox-induced configuration conversion for thioacetamide dimer can function as a molecular switch. J Comput Chem 2010; 31:2533-9. [DOI: 10.1002/jcc.21512] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Xing Y, Park TH, Venkatramani R, Keinan S, Beratan DN, Therien MJ, Borguet E. Optimizing Single-Molecule Conductivity of Conjugated Organic Oligomers with Carbodithioate Linkers. J Am Chem Soc 2010; 132:7946-56. [DOI: 10.1021/ja909559m] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yangjun Xing
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, Departments of Chemistry, Biochemistry, and Physics, Duke University, Durham, North Carolina 27708, and Department of Chemistry, French Family Science Center, Duke University, Durham, North Carolina 27708
| | - Tae-Hong Park
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, Departments of Chemistry, Biochemistry, and Physics, Duke University, Durham, North Carolina 27708, and Department of Chemistry, French Family Science Center, Duke University, Durham, North Carolina 27708
| | - Ravindra Venkatramani
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, Departments of Chemistry, Biochemistry, and Physics, Duke University, Durham, North Carolina 27708, and Department of Chemistry, French Family Science Center, Duke University, Durham, North Carolina 27708
| | - Shahar Keinan
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, Departments of Chemistry, Biochemistry, and Physics, Duke University, Durham, North Carolina 27708, and Department of Chemistry, French Family Science Center, Duke University, Durham, North Carolina 27708
| | - David N. Beratan
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, Departments of Chemistry, Biochemistry, and Physics, Duke University, Durham, North Carolina 27708, and Department of Chemistry, French Family Science Center, Duke University, Durham, North Carolina 27708
| | - Michael J. Therien
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, Departments of Chemistry, Biochemistry, and Physics, Duke University, Durham, North Carolina 27708, and Department of Chemistry, French Family Science Center, Duke University, Durham, North Carolina 27708
| | - Eric Borguet
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, Departments of Chemistry, Biochemistry, and Physics, Duke University, Durham, North Carolina 27708, and Department of Chemistry, French Family Science Center, Duke University, Durham, North Carolina 27708
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Lee SU, Mizuseki H, Kawazoe Y. Rigid adamantane tripod linkage for well-defined conductance of a single-molecule junction. Phys Chem Chem Phys 2010; 12:11763-9. [DOI: 10.1039/c001400a] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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34
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Effects of Molecular Dynamics on Electrical Conductance of Single Molecular Junction in Aqueous Solution: First Principles Calculations. E-JOURNAL OF SURFACE SCIENCE AND NANOTECHNOLOGY 2010. [DOI: 10.1380/ejssnt.2010.38] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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McCreery RL, Bergren AJ. Progress with molecular electronic junctions: meeting experimental challenges in design and fabrication. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2009; 21:4303-4322. [PMID: 26042937 DOI: 10.1002/adma.200802850] [Citation(s) in RCA: 165] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2008] [Revised: 01/26/2009] [Indexed: 05/28/2023]
Abstract
Molecular electronics seeks to incorporate molecular components as functional elements in electronic devices. There are numerous strategies reported to date for the fabrication, design, and characterization of such devices, but a broadly accepted example showing structure-dependent conductance behavior has not yet emerged. This progress report focuses on experimental methods for making both single-molecule and ensemble molecular junctions, and highlights key results from these efforts. Based on some general objectives of the field, particular experiments are presented to show progress in several important areas, and also to define those areas that still need attention. Some of the variable behavior of ostensibly similar junctions reported in the literature is attributable to differences in the way the junctions are fabricated. These differences are due, in part, to the multitude of methods for supporting the molecular layer on the substrate, including methods that utilize physical adsorption and covalent bonds, and to the numerous strategies for making top contacts. After discussing recent experimental progress in molecular electronics, an assessment of the current state of the field is presented, along with a proposed road map that can be used to assess progress in the future.
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Affiliation(s)
- Richard L McCreery
- Department of Chemistry, University of Alberta Edmonton, AB T6G 2G2 (Canada).
- National Institute for Nanotechnology, National Research Council Canada Edmonton, AB T6G 2M9 (Canada).
| | - Adam Johan Bergren
- National Institute for Nanotechnology, National Research Council Canada Edmonton, AB T6G 2M9 (Canada)
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36
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Malen JA, Doak P, Baheti K, Tilley TD, Majumdar A, Segalman RA. The nature of transport variations in molecular heterojunction electronics. NANO LETTERS 2009; 9:3406-12. [PMID: 19711966 DOI: 10.1021/nl9013875] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Transport fluctuations and variations in a series of metal-molecule-metal junctions were quantified through measurements of their thermopower. Thiol bound aromatic molecules of various lengths and degrees of freedom were chosen to understand the magnitude and origins of the variations. Junction thermopower was determined by measuring the voltage difference across molecules trapped between two gold contacts held at different temperatures. While any given measurement was remarkably stable, the breadth of distributions from repeated measurements implies variations in the offset of the highest occupied molecular orbital (HOMO) relative to the Fermi Energy of the contacts, similar in magnitude to the nominal offset itself. Statistical analysis of data shows that these variations are born at the junction formation, increase with molecular length, and are dominated by variations in contact geometry and orbital hybridization, as well as intermolecular interactions.
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Affiliation(s)
- Jonathan A Malen
- Department of Mechanical Engineering, University of California Berkeley, Berkeley, California 94720, USA
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37
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Zhou J, Chen F, Xu B. Fabrication and Electronic Characterization of Single Molecular Junction Devices: A Comprehensive Approach. J Am Chem Soc 2009; 131:10439-46. [DOI: 10.1021/ja900989a] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jianfeng Zhou
- Molecular Nanoelectronics, Faculty of Engineering & Nanoscale Science and Engineering Center, University of Georgia, Athens, Georgia 30602
| | - Fan Chen
- Molecular Nanoelectronics, Faculty of Engineering & Nanoscale Science and Engineering Center, University of Georgia, Athens, Georgia 30602
| | - Bingqian Xu
- Molecular Nanoelectronics, Faculty of Engineering & Nanoscale Science and Engineering Center, University of Georgia, Athens, Georgia 30602
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38
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Carpenter PD, Lodha S, Janes DB, Walker AV. Characterization of gold contacts in GaAs-based molecular devices: Relating structure to electrical properties. Chem Phys Lett 2009. [DOI: 10.1016/j.cplett.2009.03.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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39
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Horiguchi K, Tsutsui M, Kurokawa S, Sakai A. Electron transmission characteristics of Au/1,4-benzenedithiol/Au junctions. NANOTECHNOLOGY 2009; 20:025204. [PMID: 19417266 DOI: 10.1088/0957-4484/20/2/025204] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Electron transmission through individual 1,4-benzenedithiol molecules bridging between two gold electrodes (Au/BDT/Au junctions) has been studied by measuring the current-voltage (I-V) characteristics. Measurements were made at room temperature on three junction states of conductance 0.005G(0), 0.01G(0), and 0.1G(0), respectively, where G(0) is the quantum unit of conductance. All I-V curves are linear around zero bias and nonlinearly increase upward for biases above approximately 0.2 V. Absence of plateaus in the observed I-V characteristics up to +/- 1 V indicates that the electron transmission spectrum of Au/BDT/Au has no peaks within +/- 0.5 eV from the Fermi level.
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Affiliation(s)
- K Horiguchi
- Department of Materials Science and Engineering, Kyoto University, Kyoto, Japan
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40
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Solomon GC, Andrews DQ, Van Duyne RP, Ratner MA. Electron Transport through Conjugated Molecules: When the π System Only Tells Part of the Story. Chemphyschem 2009; 10:257-64. [DOI: 10.1002/cphc.200800591] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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