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Jing H, Yeo H, Lyu B, Ryou J, Choi S, Park JH, Lee BH, Kim YH, Lee S. Modulation of the Electronic Properties of MXene (Ti 3C 2T x) via Surface-Covalent Functionalization with Diazonium. ACS NANO 2021; 15:1388-1396. [PMID: 33400488 DOI: 10.1021/acsnano.0c08664] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The physical and chemical properties of MXenes are strongly dependent on surface terminations; thus, the tailoring of surface functional groups in two-dimensional transition-metal carbides (MXenes) may extend the applicability of these compelling materials to a wider set of fields. In this work, we demonstrate the chemical modification of Ti3C2Tx MXene via diazonium covalent chemistry and the subsequent effects on the electrical properties of MXene. The 4-nitrophenyl group was grafted onto the surface of MXene through a solid-liquid reaction, which was confirmed by various characterization methods, including X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, electron energy loss spectroscopy, atomic force microscopy, and transmission electron microscopy. The degree of modification of MXene is expediently tunable by adjusting the concentration of the diazonium salt solution. The work function of functionalized MXene is modifiable by regulating the quantity of grafted diazonium surface groups, with an adjustable range of around 0.6 eV. Further, in this study, the electrical properties of modified MXene are investigated through the fabrication of field-effect-transistor devices that utilize modified MXene as a channel material. It was demonstrated that with increasing concentration of 4-nitrophenyl groups grafted onto the surface the on/off current ratio of the modified MXene was improved to as much as 3.56, with a corresponding decrease in conductivity and mobility. The proposed approach of controlled modification of surface groups in Ti3C2Tx may imbue Ti3C2Tx with favorable electronic behaviors and demonstrate prospects for use in electronic field applications.
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Affiliation(s)
- Hongyue Jing
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 440-746, Korea
| | - Hyeonwoo Yeo
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST),291 Daehak-ro, Yuseong-gu, Daejeon 34141, Korea
| | - Benzheng Lyu
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 440-746, Korea
| | - Junga Ryou
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST),291 Daehak-ro, Yuseong-gu, Daejeon 34141, Korea
| | - Seunghyuk Choi
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 440-746, Korea
| | - Jin-Hong Park
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 440-746, Korea
| | - Byoung Hun Lee
- Department of Electrical Engineering, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Yong-Hoon Kim
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST),291 Daehak-ro, Yuseong-gu, Daejeon 34141, Korea
| | - Sungjoo Lee
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 440-746, Korea
- Department of Nano Engineering, Sungkyunkwan University, Suwon 440-746, Korea
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2
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Choi JI, Kim HS, Shin YS, Johnson C, Fomina N, Staley P, Lang C, Jang SS. Electron-Transport Characteristics through Aluminum Oxide (100) and (012) in a Metal-Insulator-Metal Junction System: Density Functional Theory-Nonequilibrium Green Function Approach. ACS OMEGA 2020; 5:1717-1724. [PMID: 32010846 PMCID: PMC6990641 DOI: 10.1021/acsomega.9b04011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 01/08/2020] [Indexed: 05/29/2023]
Abstract
Al2O3 is commonly used in modern electronic devices because of its good mechanical properties and excellent electrical insulating property. Although fundamental understanding of the electron transport in Al2O3 is essential for its use in electronic device applications, a thorough investigation for the electron-transport mechanism has not been conducted on the structures of Al2O3, especially in nanometer-scale electronic device settings. In this work, electron transport via Al2O3 for two crystallographic facets, (100) and (012), in a metal-insulator-metal junction configuration is investigated using a density functional theory-based nonequilibrium Green function method. First, it is confirmed that the transmission function, T(E), decreases as a function of energy in (E - E F) < 0 regime, which is an intuitively expected trend. On the other hand, in the (E - E F) > 0 regime, Al2O3(100) and Al2O3(012) show their own characteristic behaviors of T(E), presenting that major peaks are shifted toward lower energy levels under a finite bias voltage. Second, the overall conductance decay rates under zero bias are similar regardless of the crystallographic orientation, so that the contact interface seemingly has only a minor contribution to the overall conductance. A noteworthy feature at the finite bias condition is that the electrical current drastically increases as a function of bias potential (>0.7 V) in Al2O3(012)-based junction compared with the Al2O3(100) counterpart. It is elucidated that such a difference is due to the well-developed eigenchannels for electron transport in the Al2O3(012)-based junction. Therefore, it is evidently demonstrated that at finite bias condition, the contact interface plays a key role in determining insulating properties of Al2O3-Pt junctions.
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Affiliation(s)
- Ji Il Choi
- Computational
NanoBio Technology Laboratory, School of Materials Science and Engineering, Georgia Institute of Technology, 771 Ferst Drive NW, Atlanta, Georgia 30332-0245, United States
| | - Han Seul Kim
- National
Institute of Supercomputing and Networking, Korea Institute of Science and Technology Information, Daejeon 34141, Republic of Korea
| | - Young Shik Shin
- Research
& Technology Center, Robert Bosch LLC, 384 Santa Trinita Avenue, Sunnyvale, California 94085, United States
| | - Christopher Johnson
- Research
& Technology Center, Robert Bosch LLC, 384 Santa Trinita Avenue, Sunnyvale, California 94085, United States
| | - Nadezda Fomina
- Research
& Technology Center, Robert Bosch LLC, 384 Santa Trinita Avenue, Sunnyvale, California 94085, United States
| | - Patrick Staley
- Research
& Technology Center, Robert Bosch LLC, 384 Santa Trinita Avenue, Sunnyvale, California 94085, United States
- School
of Mathematics, Science & Engineering, Southwestern College, 900 Otay Lakes Rd, Chula Vista, California 91910-7297, United States
| | - Christoph Lang
- Research
& Technology Center, Robert Bosch LLC, 384 Santa Trinita Avenue, Sunnyvale, California 94085, United States
| | - Seung Soon Jang
- Computational
NanoBio Technology Laboratory, School of Materials Science and Engineering, Georgia Institute of Technology, 771 Ferst Drive NW, Atlanta, Georgia 30332-0245, United States
- Institute
for Electronics and Nanotechnology, Georgia
Institute of Technology, Atlanta, Georgia 30332, United States
- Strategic
Energy Institute, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
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3
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You T, Lang X, Huang A, Yin P. A DFT study on surface-enhanced Raman spectroscopy of aromatic dithiol derivatives adsorbed on gold nanojunctions. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2018; 188:222-229. [PMID: 28715690 DOI: 10.1016/j.saa.2017.07.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 07/11/2017] [Accepted: 07/11/2017] [Indexed: 06/07/2023]
Abstract
A computational study on aromatic dithiol derivatives (HS-Ar-X-Ar-SH, X=O, S, Se, NH, CH2, NN, CHCH, CC) interacting with gold cluster(s) was presented to investigate the chemical enhancement mechanism related to surface-enhanced Raman spectroscopy (SERS) for molecular junctions. Density functional theory (DFT) were performed on derivatives molecules as well as their single-end-linked (SEL) or double-end-linked (DEL) complexes for geometric, spectra, electronic and excitation properties, leading to discussions on dominant factor during SERS process. The resulted enhancement factors of SEL and DEL complexes exhibited specific dependency on linking atom or functional group between two phenyls, which was in accordance with the variation of polarizabilities and molecule-cluster transition energy.
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Affiliation(s)
- Tingting You
- School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191, China
| | - Xiufeng Lang
- Material Simulation and Computing Laboratory, Department of Physics, Hebei Normal University of Science & Technology, Qinghuangdao 066004, China
| | - Anping Huang
- School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191, China
| | - Penggang Yin
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beihang University, Beijing 100191, China.
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4
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Obersteiner V, Huhs G, Papior N, Zojer E. Unconventional Current Scaling and Edge Effects for Charge Transport through Molecular Clusters. NANO LETTERS 2017; 17:7350-7357. [PMID: 29043825 PMCID: PMC5730946 DOI: 10.1021/acs.nanolett.7b03066] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 10/17/2017] [Indexed: 05/16/2023]
Abstract
Metal-molecule-metal junctions are the key components of molecular electronics circuits. Gaining a microscopic understanding of their conducting properties is central to advancing the field. In the present contribution, we highlight the fundamental differences between single-molecule and ensemble junctions focusing on the fundamentals of transport through molecular clusters. In this way, we elucidate the collective behavior of parallel molecular wires, bridging the gap between single molecule and large-area monolayer electronics, where even in the latter case transport is usually dominated by finite-size islands. On the basis of first-principles charge-transport simulations, we explain why the scaling of the conductivity of a junction has to be distinctly nonlinear in the number of molecules it contains. Moreover, transport through molecular clusters is found to be highly inhomogeneous with pronounced edge effects determined by molecules in locally different electrostatic environments. These effects are most pronounced for comparably small clusters, but electrostatic considerations show that they prevail also for more extended systems.
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Affiliation(s)
- Veronika Obersteiner
- Institute
of Solid State Physics, NAWI Graz, Graz
University of Technology, Petersgasse 16, 8010 Graz, Austria
| | - Georg Huhs
- Barcelona
Supercomputing Center (BSC), C/Jordi Girona 29, 08034 Barcelona, Spain
- Humboldt-Universität
zu Berlin, Zum Großen
Windkanal 6, 12489 Berlin, Germany
| | - Nick Papior
- Department
of Micro- and Nanotechnology (DTU Nanotech) and Center for Nanostructured
Graphene, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
- Institut Català
de Nanociència i Nanotecnologia (ICN2), UAB Campus, Bellaterra, Spain
| | - Egbert Zojer
- Institute
of Solid State Physics, NAWI Graz, Graz
University of Technology, Petersgasse 16, 8010 Graz, Austria
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5
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Vasumathi V, Cordeiro MND. Molecular dynamics study of mixed alkanethiols covering a gold surface at three different arrangements. Chem Phys Lett 2014. [DOI: 10.1016/j.cplett.2014.03.064] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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6
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Pacheco AB, Iyengar SS. Multistageab initioquantum wavepacket dynamics for electronic structure and dynamics in open systems: Momentum representation, coupled electron-nuclear dynamics, and external fields. J Chem Phys 2011; 134:074107. [DOI: 10.1063/1.3534797] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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7
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Bennett N, Xu G, Esdaile LJ, Anderson HL, Macdonald JE, Elliott M. Transition voltage spectroscopy of porphyrin molecular wires. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2010; 6:2604-11. [PMID: 20963793 DOI: 10.1002/smll.201001046] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Measurements are presented of the current-voltage (I-V) characteristics of individual thiol-tethered porphyrin molecules (isolated in an alkanethiol matrix) and of self-assembled monolayers. In both cases, it is found that I/V(2) displays a minimum at a characteristic "transition voltage" V(m). Repeated measurements of the transition voltage enable both its time development and statistical behavior to be determined. For isolated molecules, the transition voltage shows a multipeaked distribution of values, indicating the presence of a small number of distinct molecular/contact configurations, each having different transport characteristics. For self-assembled monolayers, in contrast, a single-peaked distribution was observed, which is consistent with parallel conduction through many molecules.
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Affiliation(s)
- Neil Bennett
- School of Physics and Astronomy, Cardiff University, 5 The Parade, Cardiff CF24 3AA, UK.
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8
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Eckermann AL, Feld DJ, Shaw JA, Meade TJ. Electrochemistry of redox-active self-assembled monolayers. Coord Chem Rev 2010; 254:1769-1802. [PMID: 20563297 PMCID: PMC2885823 DOI: 10.1016/j.ccr.2009.12.023] [Citation(s) in RCA: 359] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Redox-active self-assembled monolayers (SAMs) provide an excellent platform for investigating electron transfer kinetics. Using a well-defined bridge, a redox center can be positioned at a fixed distance from the electrode and electron transfer kinetics probed using a variety of electrochemical techniques. Cyclic voltammetry, AC voltammetry, electrochemical impedance spectroscopy, and chronoamperometry are most commonly used to determine the rate of electron transfer of redox-activated SAMs. A variety of redox species have been attached to SAMs, and include transition metal complexes (e.g., ferrocene, ruthenium pentaammine, osmium bisbipyridine, metal clusters) and organic molecules (e.g., galvinol, C(60)). SAMs offer an ideal environment to study the outer-sphere interactions of redox species. The composition and integrity of the monolayer and the electrode material influence the electron transfer kinetics and can be investigated using electrochemical methods. Theoretical models have been developed for investigating SAM structure. This review discusses methods and monolayer compositions for electrochemical measurements of redox-active SAMs.
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9
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Pacheco AB, Iyengar SS. A multistageab initioquantum wavepacket dynamics formalism for electronic structure and dynamics in open systems. J Chem Phys 2010; 133:044105. [DOI: 10.1063/1.3463798] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Alexander B. Pacheco
- Department of Chemistry and Department of Physics, Indiana University, Bloomington, Indiana 47405, USA
| | - Srinivasan S. Iyengar
- Department of Chemistry and Department of Physics, Indiana University, Bloomington, Indiana 47405, USA
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10
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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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11
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Fabiano E, Piacenza M, D'Agostino S, Della Sala F. Towards an accurate description of the electronic properties of the biphenylthiol/gold interface: the role of exact exchange. J Chem Phys 2010; 131:234101. [PMID: 20025308 DOI: 10.1063/1.3271393] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
We investigate the role of the exact exchange in describing the biphenylthiol/gold interface. The study is performed by simulating the electronic properties of mercaptobiphenylthiol and aminobiphenylthiol molecules adsorbed on a Au(23) cluster, using local, semilocal and hybrid functionals and an effective exact exchange method, namely, the localized Hartree-Fock (LHF). We find that the local/semilocal functionals strongly underestimate the charge transfer and the bond dipole at the interface due to the self-interaction-error (SIE), which alters the correct level alignment. On the other hand the LHF method is SIE free and predicts a larger charge transfer and bond dipole. We also found that LHF results can be reproduced using hybrid functionals and that conventional local/semilocal correlation functionals are unable to improve over the exchange-only description.
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Affiliation(s)
- E Fabiano
- National Nanotechnology Laboratory of CNR-INFM, IIT Research Unit, Distretto Tecnologico ISUFI, Via per Arnesano, I-73100 Lecce, Italy
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12
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George C, Yoshida H, Goddard WA, Jang SS, Kim YH. Charge transport through polyene self-assembled monolayers from multiscale computer simulations. J Phys Chem B 2008; 112:14888-97. [PMID: 18947250 DOI: 10.1021/jp061759l] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We combine first-principles density-functional theory with matrix Green's function calculations to predict the structures and charge transport characteristics of self-assembled monolayers (SAMs) of four classes of systems in contact with Au(111) electrodes: conjugated polyene chains (n = 4, 8, 12, 16, and 30) thiolated at one or both ends and saturated alkane chains (n = 4, 8, 12, and 16) thiolated at one or both ends. For the polyene SAMs, we find no decay in the current as a function of chain length and conclude that these 1-3 nm long polyene SAMs act as metallic wires. We also find that the polyene-monothiolate leads to a contact resistance only 2.8 times higher than that for the polyene-dithiolate chains, indicating that the device conductance is dominated by the properties of the molecular connector with less importance in having a second molecule-electrode contact. For the alkane SAMs, we observe the normal exponential decay in the current as a function of the chain length with a decay constant of beta(n) = 0.82 for the alkane-monothiolate and 0.88 for the alkane-dithiolate. We find that the contact resistance for the alkane-monothiolate is 12.5 times higher than that for the alkane-dithiolate chains, reflecting the extra resistance due to the weak contact on the nonthiolated end. These contrasting charge transport characteristics of alkane and polyene SAMs and their contact dependence are explained in terms of the atomic projected density of states.
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Affiliation(s)
- Christopher George
- Materials and Process Simulation Center (139-74), California Institute of Technology, Pasadena, California 91125, USA
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13
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Goujon F, Bonal C, Limoges B, Malfreyt P. Molecular Dynamics Description of Grafted Monolayers: Effect of the Surface Coverage. J Phys Chem B 2008; 112:14221-9. [DOI: 10.1021/jp8028825] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- F. Goujon
- Laboratoire de Thermodynamique et Interactions Moléculaires de lʼUniversité Blaise Pascal (Clermont-Ferrand II), FRE 3099, 24 Avenue des Landais, 63177 Aubière Cedex, and Laboratoire dʼElectrochimie Moléculaire de lʼUniversité Denis Diderot (Paris 7), UMR CNRS 7591, 2 Place Jussieu, 75251 Paris Cedex 05, France
| | - C. Bonal
- Laboratoire de Thermodynamique et Interactions Moléculaires de lʼUniversité Blaise Pascal (Clermont-Ferrand II), FRE 3099, 24 Avenue des Landais, 63177 Aubière Cedex, and Laboratoire dʼElectrochimie Moléculaire de lʼUniversité Denis Diderot (Paris 7), UMR CNRS 7591, 2 Place Jussieu, 75251 Paris Cedex 05, France
| | - B. Limoges
- Laboratoire de Thermodynamique et Interactions Moléculaires de lʼUniversité Blaise Pascal (Clermont-Ferrand II), FRE 3099, 24 Avenue des Landais, 63177 Aubière Cedex, and Laboratoire dʼElectrochimie Moléculaire de lʼUniversité Denis Diderot (Paris 7), UMR CNRS 7591, 2 Place Jussieu, 75251 Paris Cedex 05, France
| | - P. Malfreyt
- Laboratoire de Thermodynamique et Interactions Moléculaires de lʼUniversité Blaise Pascal (Clermont-Ferrand II), FRE 3099, 24 Avenue des Landais, 63177 Aubière Cedex, and Laboratoire dʼElectrochimie Moléculaire de lʼUniversité Denis Diderot (Paris 7), UMR CNRS 7591, 2 Place Jussieu, 75251 Paris Cedex 05, France
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14
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Goujon F, Bonal C, Limoges B, Malfreyt P. Molecular simulations of grafted metal-chelating monolayers: methodology, structure and energy. Mol Phys 2008. [DOI: 10.1080/00268970802235557] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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15
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Andrews DQ, Van Duyne RP, Ratner MA. Stochastic modulation in molecular electronic transport junctions: molecular dynamics coupled with charge transport calculations. NANO LETTERS 2008; 8:1120-1126. [PMID: 18351748 DOI: 10.1021/nl073265l] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The experimental variation in conductance that can be expected through dynamically evolving Au-molecule-Au junctions is approximated using molecular dynamics to model thermal fluctuations and a nonequilibrium Green's function code (Hückel-IV 2.0) to calculate the charge transport. This generates a statistical set of conductance data that can be used to compare directly with experimental results. Experimental measurements on Au-single molecule junctions show a large variation in conductance values between different identically prepared junctions. Our computational results indicate that the Au-Au and the Au-molecule fluctuations provide extensive geometric freedom and an associated broad distribution in calculated conductance values. Our results show agreement with experimental measurements of the low bias voltage conductance and conductance distribution for both thiol-Au and amine-Au linker structures. -
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Affiliation(s)
- David Q Andrews
- Northwestern University, 2145 Sheridan Road, EVanston, IL 60208, USA.
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16
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Dirama TE, Johnson JA. Conformation and dynamics of arylthiol self-assembled monolayers on Au(111). LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:12208-12216. [PMID: 17958384 DOI: 10.1021/la7015963] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We report a computational investigation of the conformation and the dynamics of self-assembled monolayers (SAMs) of a set of aromatic thiols arranged in the ( radical3 x radical3)-R30 degrees packing ratio on a Au(111) surface using molecular dynamics (MD) simulations. It was found that the molecular conformations were better defined for the arylthiol with two phenyl groups as compared to those with a single phenyl group and that the chemical structure of the head and tail groups had a considerable influence on the system geometry. In line with the density functional theory (DFT) calculations of small thiol molecules, we found for the SAMs that the face-centered cubic (fcc) site on the Au(111) surface was the most preferred, followed by the hexagonal close-packed (hcp) site, while the bridge position showed the characteristics of a local energy maximum. The dynamics of thiol head groups on these three Au sites was found to govern the overall dynamics of SAMs as measured by the mean square displacement. We also report that both the conformation and the dynamics on the studied time scale were driven by the SAM formation energy.
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Affiliation(s)
- Taner E Dirama
- Universal Technology Corporation, 1270 North Fairfield Road, Dayton, OH 45432-2600, USA.
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17
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Zou B, Li ZL, Song XN, Luo Y, Wang CK. Effects of field-induced geometry relaxation on the electron transport properties of 4,4′-biphenyldithiol molecular junction. Chem Phys Lett 2007. [DOI: 10.1016/j.cplett.2007.08.076] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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