1
|
O'Driscoll LJ, Bryce MR. A review of oligo(arylene ethynylene) derivatives in molecular junctions. NANOSCALE 2021; 13:10668-10711. [PMID: 34110337 DOI: 10.1039/d1nr02023d] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Oligo(arylene ethynylene) (OAE) derivatives are the "workhorse" molecules of molecular electronics. Their ease of synthesis and flexibility of functionalisation mean that a diverse array of OAE molecular wires have been designed, synthesised and studied theoretically and experimentally in molecular junctions using both single-molecule and ensemble methods. This review summarises the breadth of molecular designs that have been investigated with emphasis on structure-property relationships with respect to the electronic conductance of OAEs. The factors considered include molecular length, connectivity, conjugation, (anti)aromaticity, heteroatom effects and quantum interference (QI). Growing interest in the thermoelectric properties of OAE derivatives, which are expected to be at the forefront of research into organic thermoelectric devices, is also explored.
Collapse
Affiliation(s)
- Luke J O'Driscoll
- Department of Chemistry, Durham University, Lower Mountjoy, Stockton Road, Durham, UKDH1 3LE.
| | - Martin R Bryce
- Department of Chemistry, Durham University, Lower Mountjoy, Stockton Road, Durham, UKDH1 3LE.
| |
Collapse
|
2
|
Fu Z, Ladnorg T, Gliemann H, Welle A, Bashir A, Rohwerder M, Zhang Q, Schüpbach B, Terfort A, Wöll C. Mobility of charge carriers in self-assembled monolayers. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2019; 10:2449-2458. [PMID: 31921523 PMCID: PMC6941449 DOI: 10.3762/bjnano.10.235] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Accepted: 11/12/2019] [Indexed: 06/10/2023]
Abstract
We present a new approach to study charge transport within 2D layers of organic semi-conductors (OSCs) using atomic force microscopy (AFM)-based lithography applied to self-assembled monolayers (SAMs), fabricated from appropriate organothiols. The extent of lateral charge transport was investigated by insulating pre-defined patches within OSC-based SAMs with regions of insulating SAM made from large band gap alkanethiolates. The new method is demonstrated using a phenyl-linked anthracenethiolate (PAT), 4-(anthracene-2-ylethynyl)benzyl thiolate. I-V characteristics of differently shaped PAT-islands were measured using the AFM tip as a top electrode. We were able to determine a relationship between island size and electrical conductivity, and from this dependence, we could obtain information on the lateral charge transport and charge carrier mobility within the thin OSC layers. Our study demonstrates that AFM nanografting of appropriately functionalized OSC molecules provides a suitable method to determine intrinsic mobilities of charge carriers in OSC thin films. In particular, this method is rather insensitive with regard to influence of grain boundaries and other defects, which hamper the application of conventional methods for the determination of mobilities in macroscopic samples.
Collapse
Affiliation(s)
- Zhihua Fu
- Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), Campus Nord, 76344 Eggenstein-Leopoldshafen, Germany
| | - Tatjana Ladnorg
- Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), Campus Nord, 76344 Eggenstein-Leopoldshafen, Germany
| | - Hartmut Gliemann
- Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), Campus Nord, 76344 Eggenstein-Leopoldshafen, Germany
| | - Alexander Welle
- Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), Campus Nord, 76344 Eggenstein-Leopoldshafen, Germany
| | - Asif Bashir
- Max-Planck-Institut für Eisenforschung GmbH, 40237 Düsseldorf, Germany
- Thyssenkrupp Bilstein GmbH, Herner Str. 299, 44809 Bochum, Germany
| | - Michael Rohwerder
- Max-Planck-Institut für Eisenforschung GmbH, 40237 Düsseldorf, Germany
| | - Qiang Zhang
- Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), Campus Nord, 76344 Eggenstein-Leopoldshafen, Germany
| | - Björn Schüpbach
- Department of Chemistry, Institute of Inorganic and Analytical Chemistry, Goethe-University, 60438 Frankfurt, Germany
| | - Andreas Terfort
- Department of Chemistry, Institute of Inorganic and Analytical Chemistry, Goethe-University, 60438 Frankfurt, Germany
| | - Christof Wöll
- Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), Campus Nord, 76344 Eggenstein-Leopoldshafen, Germany
| |
Collapse
|
3
|
Jeong H, Kim D, Xiang D, Lee T. High-Yield Functional Molecular Electronic Devices. ACS NANO 2017; 11:6511-6548. [PMID: 28578582 DOI: 10.1021/acsnano.7b02967] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
An ultimate goal of molecular electronics, which seeks to incorporate molecular components into electronic circuit units, is to generate functional molecular electronic devices using individual or ensemble molecules to fulfill the increasing technical demands of the miniaturization of traditional silicon-based electronics. This review article presents a summary of recent efforts to pursue this ultimate aim, covering the development of reliable device platforms for high-yield ensemble molecular junctions and their utilization in functional molecular electronic devices, in which distinctive electronic functionalities are observed due to the functional molecules. In addition, other aspects pertaining to the practical application of molecular devices such as manufacturing compatibility with existing complementary metal-oxide-semiconductor technology, their integration, and flexible device applications are also discussed. These advances may contribute to a deeper understanding of charge transport characteristics through functional molecular junctions and provide a desirable roadmap for future practical molecular electronics applications.
Collapse
Affiliation(s)
- Hyunhak Jeong
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University , Seoul 08826, Korea
| | - Dongku Kim
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University , Seoul 08826, Korea
| | - Dong Xiang
- Key Laboratory of Optical Information Science and Technology, Institute of Modern Optics, College of Electronic Information and Optical Engineering, Nankai University , Tianjin 300071, China
| | - Takhee Lee
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University , Seoul 08826, Korea
| |
Collapse
|
4
|
Zhang Y, Zhao Z, Fracasso D, Chiechi RC. Bottom-Up Molecular Tunneling Junctions Formed by Self-Assembly. Isr J Chem 2014. [DOI: 10.1002/ijch.201400033] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
5
|
Del Re J, Moore MH, Ratna BR, Blum AS. Molecular sensing: modulating molecular conduction through intermolecular interactions. Phys Chem Chem Phys 2013; 15:8318-23. [PMID: 23615512 DOI: 10.1039/c3cp43420f] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We observe changes in the molecular conductivity of individual oligophenylene-vinylene (OPV) molecules due to interactions with small aromatic molecules. Fluorescence experiments were correlated with scanning tunneling microscopy measurements in order to determine the origin of the observed effect. Both nitrobenzene and 1,4-dinitrobenzene decreased fluorescence intensity and molecular conductivity, while toluene had no effect. The observed changes in the fluorescence and conduction of OPV correlate well with the electron withdrawing ability of the interacting aromatic molecules. These results demonstrate the potential usefulness of OPV as a sensor for aromatic compounds containing electron withdrawing groups.
Collapse
Affiliation(s)
- Julia Del Re
- McGill University, 801 Sherbrooke St W., Montreal, Canada H3A 0B8
| | | | | | | |
Collapse
|
6
|
Abstract
Several aspects of intermolecular effects in molecular conduction have been studied in recent years. These experimental and theoretical studies, made on several setups of molecular conduction junctions, have focused on the current-voltage characteristic that is usually dominated by the elastic transmission properties of such junctions. In this paper, we address cooperative intermolecular effects in the inelastic tunneling signal calculated for simple generic models of such systems. We find that peak heights in the inelastic (d(2)I/dE(2) vs E) spectrum may be affected by such cooperative effects even when direct intermolecular interactions can be disregarded. This finding suggests that comparing experimental results to calculations made on single-molecule junctions should be done with care.
Collapse
Affiliation(s)
- Michael Galperin
- Department of Chemistry & Biochemistry, University of California at San Diego, La Jolla, California 92093, USA
| | | |
Collapse
|
7
|
Zhou J, Guo C, Xu B. Electron transport properties of single molecular junctions under mechanical modulations. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:164209. [PMID: 22466314 DOI: 10.1088/0953-8984/24/16/164209] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Electron transport behaviors of single molecular junctions are very sensitive to the atomic scale molecule-metal electrode contact interfaces, which have been difficult to control. We used a modified scanning probe microscope-break junction technique (SPM-BJT) to control the dynamics of the contacts and simultaneously monitor both the conductance and force. First, by fitting the measured data into a modified multiple tunneling barrier model, the static contact resistances, corresponding to the different contact conformations of single alkanedithiol and alkanediamine molecular junctions, were identified. Second, the changes of contact decay constant were measured under mechanical extensions of the molecular junctions, which helped to classify the different single molecular conductance sets into specific microscopic conformations of the molecule-electrode contacts. Third, by monitoring the changes of force and contact decay constant with the mechanical extensions, the changes of conductance were found to be caused by the changes of contact bond length and by the atomic reorganizations near the contact bond. This study provides a new insight into the understanding of the influences of contact conformations, especially the effect of changes of dynamic contact conformation on electron transport through single molecular junctions.
Collapse
Affiliation(s)
- Jianfeng Zhou
- Faculty of Engineering and Nanoscale Science and Engineering Center, University of Georgia, Athens, GA 30602, USA
| | | | | |
Collapse
|
8
|
Molecular electronic junction transport: some pathways and some ideas. Top Curr Chem (Cham) 2011. [PMID: 21915776 DOI: 10.1007/128_2011_227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
When a single molecule, or a collection of molecules, is placed between two electrodes and voltage is applied, one has a molecular transport junction. We discuss such junctions, their properties, their description, and some of their applications. The discussion is qualitative rather than quantitative, and focuses on mechanism, structure/function relations, regimes and mechanisms of transport, some molecular regularities, and some substantial challenges facing the field. Because there are many regimes and mechanisms in transport junctions, we will discuss time scales, geometries, and inelastic scattering methods for trying to determine the properties of molecules within these junctions. Finally, we discuss some device applications, some outstanding problems, and some future directions.
Collapse
|
9
|
Nakayama H, Kimura S. Suppression of HOMO–LUMO Transition in a Twist Form of Oligo(phenyleneethynylene) Clamped by a Right-Handed Helical Peptide. J Phys Chem A 2011; 115:8960-8. [DOI: 10.1021/jp200997c] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hidenori Nakayama
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Kyoto-Daigaku-Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Shunsaku Kimura
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Kyoto-Daigaku-Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| |
Collapse
|
10
|
Wang LJ, Zhou KG, Tan L, Wang H, Shi ZF, Wu GP, Xu ZG, Cao XP, He HX, Zhang HL. A core-shell strategy for constructing a single-molecule junction. Chemistry 2011; 17:8414-23. [PMID: 21656581 DOI: 10.1002/chem.201003507] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Revised: 03/10/2011] [Indexed: 11/12/2022]
Abstract
Understanding the effects of intermolecular interactions on the charge-transport properties of metal/molecule/metal junctions is an important step towards using individual molecules as building blocks for electronic devices. This work reports a systematic electron-transport investigation on a series of "core-shell"-structured oligo(phenylene ethynylene) (Gn-OPE) molecular wires. By using dendrimers of different generations as insulating "shells", the intermolecular π-π interactions between the OPE "cores" can be precisely controlled in single-component monolayers. Three techniques are used to evaluate the electron-transport properties of the Au/Gn-OPE/Au molecular junctions, including crossed-wire junction, scanning tunneling spectroscopy (STS), and scanning tunneling microscope (STM) break-junction techniques. The STM break-junction measurement reveals that the electron-transport pathways are strongly affected by the size of the side groups. When the side groups are small, electron transport could occur through three pathways, including through single-molecule junctions, double-molecule junctions, and molecular bridges between adjacent molecules formed by aromatic π-π coupling. The dendrimer shells effectively prohibit the π-π coupling effect, but at the same time, very large dendrimer side groups may hinder the formation of Au-S bonds. A first-generation dendrimer acts as an optimal shell that only allows electron transport through the single-molecule junction pathway, and forbids the other undesired pathways. It is demonstrated that the dendrimer-based core-shell strategy allows the single-molecule conductance to be probed in a homogenous monolayer without the influence of intermolecular π-π interactions.
Collapse
Affiliation(s)
- Le-Jia Wang
- State Key Laboratory of Applied Organic Chemistry (SKLAOC), College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, 730000, China
| | | | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Blum AS, Soto CM, Sapsford KE, Wilson CD, Moore MH, Ratna BR. Molecular electronics based nanosensors on a viral scaffold. Biosens Bioelectron 2011; 26:2852-7. [DOI: 10.1016/j.bios.2010.11.021] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Revised: 11/04/2010] [Accepted: 11/15/2010] [Indexed: 10/18/2022]
|
12
|
Wang G, Kim TW, Lee T. Electrical transport characteristics through molecular layers. ACTA ACUST UNITED AC 2011. [DOI: 10.1039/c1jm12702k] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
13
|
Sherratt PAJ, Cohen H, Seideman T. The information content of electron flow through adsorbed molecular monolayers. J Chem Phys 2009; 131:234701. [DOI: 10.1063/1.3273452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
14
|
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: 224] [Impact Index Per Article: 14.9] [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.
Collapse
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)
| |
Collapse
|
15
|
Widawsky JR, Kamenetska M, Klare J, Nuckolls C, Steigerwald ML, Hybertsen MS, Venkataraman L. Measurement of voltage-dependent electronic transport across amine-linked single-molecular-wire junctions. NANOTECHNOLOGY 2009; 20:434009. [PMID: 19801764 DOI: 10.1088/0957-4484/20/43/434009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
We measure the conductance and current-voltage characteristics of two amine-terminated molecular wires -- 4,4'-diaminostilbene and bis-(4-aminophenyl)acetylene -- by breaking Au point contacts in a molecular solution at room temperature. Histograms compiled from thousands of measurements show a slight increase in the molecular junction conductance (I/V) as the bias is increased to nearly 450 mV. Comparatively, similar conductance measurements made with 1,6-diaminohexane, a saturated molecule, demonstrate almost no bias dependence. We also present a new technique to measure a statistically defined current-voltage (I-V) curve. Application to all three molecules shows that 4,4'-diaminostilbene exhibits the largest increase in differential conductance as a function of applied bias. This indicates that the predominant transport channel for 4,4'-diaminostilbene (the highest occupied molecular orbital) is closer to the Fermi level of the metal than that of the other molecules, consistent with the trends observed in the molecular ionization potential. We find that junctions constructed with the conjugated molecules show greater noise in individual junctions and less structural stability, on average, at biases greater than 450 mV. In contrast, junctions formed with the alkane can sustain a bias of up to 900 mV. This significantly affects the statistically averaged I-V characteristic measured for the conjugated molecules at higher bias.
Collapse
Affiliation(s)
- J R Widawsky
- Department of Applied Physics and Applied Mathematics, Columbia University, NY 10027, USA
| | | | | | | | | | | | | |
Collapse
|
16
|
Terada K, Kobayashi K, Hikita J, Haga MA. Electric Conduction Properties of Self-assembled Monolayer Films of Ru Complexes with Disulfide/Phosphonate Anchors in a Au–(Molecular Ensemble)–(Au Nanoparticle) Junction. CHEM LETT 2009. [DOI: 10.1246/cl.2009.416] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
|
17
|
Wu S, González MT, Huber R, Grunder S, Mayor M, Schönenberger C, Calame M. Molecular junctions based on aromatic coupling. NATURE NANOTECHNOLOGY 2008; 3:569-74. [PMID: 18772920 DOI: 10.1038/nnano.2008.237] [Citation(s) in RCA: 233] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2008] [Accepted: 07/16/2008] [Indexed: 05/21/2023]
Abstract
If individual molecules are to be used as building blocks for electronic devices, it will be essential to understand charge transport at the level of single molecules. Most existing experiments rely on the synthesis of functional rod-like molecules with chemical linker groups at both ends to provide strong, covalent anchoring to the source and drain contacts. This approach has proved very successful, providing quantitative measures of single-molecule conductance, and demonstrating rectification and switching at the single-molecule level. However, the influence of intermolecular interactions on the formation and operation of molecular junctions has been overlooked. Here we report the use of oligo-phenylene ethynylene molecules as a model system, and establish that molecular junctions can still form when one of the chemical linker groups is displaced or even fully removed. Our results demonstrate that aromatic pi-pi coupling between adjacent molecules is efficient enough to allow for the controlled formation of molecular bridges between nearby electrodes.
Collapse
Affiliation(s)
- Songmei Wu
- Department of Physics, University of Basel, Klingelbergstrasse. 82, CH-4056 Basel, Switzerland
| | | | | | | | | | | | | |
Collapse
|
18
|
Morita T, Lindsay S. Reduction-Induced Switching of Single-Molecule Conductance of Fullerene Derivatives. J Phys Chem B 2008; 112:10563-72. [DOI: 10.1021/jp8021387] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tomoyuki Morita
- Biodesign Institute, Department of Chemistry and Biochemistry, and Department of Physics, Arizona State University, Tempe, Arizona 85287, and Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Kyoto-Daigaku-Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Stuart Lindsay
- Biodesign Institute, Department of Chemistry and Biochemistry, and Department of Physics, Arizona State University, Tempe, Arizona 85287, and Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Kyoto-Daigaku-Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| |
Collapse
|
19
|
Zangmeister CD, Beebe JM, Naciri J, Kushmerick JG, van Zee RD. Controlling charge-carrier type in nanoscale junctions with linker chemistry. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2008; 4:1143-1147. [PMID: 18623298 DOI: 10.1002/smll.200800359] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Affiliation(s)
- Christopher D Zangmeister
- Chemical Science and Technology Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
| | | | | | | | | |
Collapse
|
20
|
Beebe JM, Kim B, Frisbie CD, Kushmerick JG. Measuring relative barrier heights in molecular electronic junctions with transition voltage spectroscopy. ACS NANO 2008; 2:827-832. [PMID: 19206478 DOI: 10.1021/nn700424u] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Though molecular devices exhibiting potentially useful electrical behavior have been demonstrated, a deep understanding of the factors that influence charge transport in molecular electronic junctions has yet to be fully realized. Recent work has shown that a mechanistic transition occurs from direct tunneling to field emission in molecular electronic devices. The magnitude of the voltage required to enact this transition is molecule-specific, and thus measurement of the transition voltage constitutes a form of spectroscopy. Here we determine that the transition voltage for a series of alkanethiol molecules is invariant with molecular length, while the transition voltage of a conjugated molecule depends directly on the manner in which the conjugation pathway has been extended. Finally, by examining the transition voltage as a function of contact metal, we show that this technique can be used to determine the dominant charge carrier for a given molecular junction.
Collapse
Affiliation(s)
- Jeremy M Beebe
- National Institute of Standards and Technology, Gaithersburg, Maryland, 20899, USA
| | | | | | | |
Collapse
|
21
|
Nakamura H, Yamashita K. Systematic study on quantum confinement and waveguide effects for elastic and inelastic currents in atomic gold wire: importance of the phase factor for modeling electrodes. NANO LETTERS 2008; 8:6-12. [PMID: 18081352 DOI: 10.1021/nl071281c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Quantum confinement of the electrodes is an important issue for electron transport through molecular or atomic wire junctions. To assess the importance of waveguide effects by quantum confinement of the electrodes, we have calculated elastic and inelastic conductance and inelastic electron tunneling spectra of atomic gold wire with gold electrodes for several models. The results show the quite important role of the phase factors between the modeled electrodes and the contact region.
Collapse
Affiliation(s)
- Hisao Nakamura
- Department of Chemical System Engineering, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan.
| | | |
Collapse
|
22
|
Danilov A, Kubatkin S, Kafanov S, Hedegård P, Stuhr-Hansen N, Moth-Poulsen K, Bjørnholm T. Electronic transport in single molecule junctions: control of the molecule-electrode coupling through intramolecular tunneling barriers. NANO LETTERS 2008; 8:1-5. [PMID: 18085806 DOI: 10.1021/nl071228o] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We report on single molecule electron transport measurements of two oligophenylenevinylene (OPV3) derivatives placed in a nanogap between gold (Au) or lead (Pb) electrodes in a field effect transistor device. Both derivatives contain thiol end groups that allow chemical binding to the electrodes. One derivative has additional methylene groups separating the thiols from the delocalized pi-electron system. The insertion of methylene groups changes the open state conductance by 3-4 orders of magnitude and changes the transport mechanism from a coherent regime with finite zero-bias conductance to sequential tunneling and Coulomb blockade behavior.
Collapse
Affiliation(s)
- Andrey Danilov
- Nano-Science Center (Niels Bohr Institute and Department of Chemistry), University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
| | | | | | | | | | | | | |
Collapse
|
23
|
Ashwell GJ, Wierzchowiec P, Phillips LJ, Collins CJ, Gigon J, Robinson BJ, Finch CM, Grace IR, Lambert CJ, Buckle PD, Ford K, Wood BJ, Gentle IR. Functional molecular wires. Phys Chem Chem Phys 2008; 10:1859-66. [DOI: 10.1039/b719417j] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
24
|
Xu B. Modulating the conductance of a Au-octanedithiol-Au molecular junction. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2007; 3:2061-2065. [PMID: 18022974 DOI: 10.1002/smll.200700287] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Affiliation(s)
- Bingqian Xu
- Molecular Nanoelectronics, Faculty of Engineering & Nanoscale Science and Engineering Center, University of Georgia, Athens, GA 30602, USA.
| |
Collapse
|
25
|
Blum AS, Soto CM, Wilson CD, Amsinck C, Franzon P, Ratna BR. Electronic Properties of Molecular Memory Circuits on a Nanoscale Scaffold. IEEE Trans Nanobioscience 2007; 6:270-4. [DOI: 10.1109/tnb.2007.908978] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
26
|
Bazan GC. Novel organic materials through control of multichromophore interactions. J Org Chem 2007; 72:8615-35. [PMID: 17887701 DOI: 10.1021/jo071176n] [Citation(s) in RCA: 165] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The function of organic semiconducting and light-harvesting materials depends on the organization of the individual molecular components. Our group has tackled the problem of through-space delocalization via the design and synthesis of bichromphoric pairs held in close proximity by the [2.2]paracyclophane core. The linear and nonlinear optical properties of these molecules provide a challenge to theory. They are also useful in delineating the problem of intermolecular contacts in molecular conductivity measurements. Another area of research described here concerns conjugated polyelectrolytes. These macromolecules combine the properties of organic semiconductors and conventional polyelectrolytes. We have used these materials in the development of optically amplified biosensors and have also incorporated them into organic optoelectronic devices. Of particular interest to us is to derive useful structure/property relationships via molecular design that address important basic scientific problems and technological challenges.
Collapse
Affiliation(s)
- Guillermo C Bazan
- Department of Chemistry, Institute for Polymers and Organic Solids, University of California, Santa Barbara, CA 93106, USA.
| |
Collapse
|
27
|
Albinsson B, Eng MP, Pettersson K, Winters MU. Electron and energy transfer in donor-acceptor systems with conjugated molecular bridges. Phys Chem Chem Phys 2007; 9:5847-64. [PMID: 17989792 DOI: 10.1039/b706122f] [Citation(s) in RCA: 170] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electron and energy transfer reactions in covalently connected donor-bridge-acceptor assemblies are strongly dependent, not only on the donor-acceptor distance, but also on the electronic structure of the bridge. In this article we describe some well characterised systems where the bridges are pi-conjugated chromophores, and where, specifically, the interplay between bridge length and energy plays an important role for the donor-acceptor electronic coupling. For any application that relies on the transport of electrons, for example molecule based solar cells or molecular scale electronics, it will be imperative to predict the electron transfer capabilities of different molecular structures. The potential difficulties with making such predictions and the lack of suitable models are also discussed.
Collapse
Affiliation(s)
- Bo Albinsson
- Department of Chemical and Biological Engineering/Physical Chemistry, Chalmers University of Technology, SE-412 96, Göteborg, Sweden.
| | | | | | | |
Collapse
|
28
|
Weiss EA, Kriebel JK, Rampi MA, Whitesides GM. The study of charge transport through organic thin films: mechanism, tools and applications. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2007; 365:1509-37. [PMID: 17430810 DOI: 10.1098/rsta.2007.2029] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
In this paper, we discuss the current state of organic and molecular-scale electronics, some experimental methods used to characterize charge transport through molecular junctions and some theoretical models (superexchange and barrier tunnelling models) used to explain experimental results. Junctions incorporating self-assembled monolayers of organic molecules - and, in particular, junctions with mercury-drop electrodes - are described in detail, as are the issues of irreproducibility associated with such junctions (due, in part, to defects at the metal-molecule interface).
Collapse
Affiliation(s)
- Emily A Weiss
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA 02138, USA
| | | | | | | |
Collapse
|
29
|
Villares A, Lydon DP, Porrès L, Beeby A, Low PJ, Cea P, Royo FM. Preparation of Ordered Films Containing a Phenylene Ethynylene Oligomer by the Langmuir−Blodgett Technique. J Phys Chem B 2007; 111:7201-9. [PMID: 17552562 DOI: 10.1021/jp072052h] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This paper reports the fabrication and characterization of Langmuir and Langmuir-Blodgett (LB) films incorporating an oligo(phenylene-ethynylene) (OPE) derivative, namely, 4-[4-(4-hexyloxyphenylethynyl)-phenylethynyl]-benzoic acid (HBPEB). Conditions appropriate for deposition of monolayers of HBPEB at the air-water interface have been established and the resulting Langmuir films characterized by a combination of surface pressure and surface potential versus area per molecule isotherms, Brewster angle microscopy, and ultraviolet reflection spectroscopy. The Langmuir films are readily transferred onto solid substrates, and one-layer LB films transferred at several surface pressures onto mica substrates have been analyzed by means of atomic force microscopy, from which it can be concluded that 14 mN/m is an optimum surface pressure of transference, giving well-ordered homogeneous films without three-dimensional defects and a low surface roughness. The optical and emissive properties of the LB films have been determined with significant blue-shifted absorption spectra indicating formation of two-dimensional H aggregates and a Stokes shift illustrating the effects of the solid-like environment on the molecular chromophore.
Collapse
Affiliation(s)
- Ana Villares
- Departamento de Química OrgAnica-Química Física, Area de Química Física, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain
| | | | | | | | | | | | | |
Collapse
|
30
|
Yokota Y, Fukui KI, Enoki T, Hara M. Strong Intermolecular Electronic Coupling within a Tetrathiafulvalene Island Embedded in Self-Assembled Monolayers. J Am Chem Soc 2007; 129:6571-5. [PMID: 17465548 DOI: 10.1021/ja070632m] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Electroactive tetrathiafulvalene thiol, specially designed to pursue an intermolecular electronic coupling, was embedded in an n-alkanethiol SAM matrix as islands and was studied under potential control using in situ scanning tunneling microscopy. The apparent height of the islands increased with the island size, irrespective of the oxidation state of the tetrathiafulvalene backbones. This behavior can be rationalized on the basis of the strong intermolecular electronic coupling that creates efficient intermolecular conduction paths.
Collapse
Affiliation(s)
- Yasuyuki Yokota
- Department of Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8551, Japan
| | | | | | | |
Collapse
|
31
|
Milani F, Grave C, Ferri V, Samorì P, Rampi MA. Ultrathin π-Conjugated Polymer Films for Simple Fabrication of Large-Area Molecular Junctions. Chemphyschem 2007; 8:515-8. [PMID: 17286324 DOI: 10.1002/cphc.200600672] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Federico Milani
- Dipartimento di Chimica, Università di Ferrara, Via Borsari 46, 44100 Ferrara, Italy
| | | | | | | | | |
Collapse
|
32
|
Na JS, Ayres J, Chandra KL, Chu C, Gorman CB, Parsons GN. Conduction mechanisms and stability of single molecule nanoparticle/molecule/nanoparticle junctions. NANOTECHNOLOGY 2007; 18:035203. [PMID: 19636113 DOI: 10.1088/0957-4484/18/3/035203] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Nanoparticle/molecule/nanoparticle dimer assemblies have been successfully trapped by dielectrophoresis across nanogap electrodes, enabling temperature dependent charge transport measurements through an oligomeric phenylene ethynylene molecule, and transition from direct tunnelling to Fowler-Nordheim tunnelling is observed at approximately 1.5 V. Samples formed by dielectrophoresis show better contact stability than those formed by receding meniscus. The junction shows stable operation over several weeks in a vacuum, but current increases with time upon exposure to air, possibly due to the adsorbed water molecules near the molecule/gold nanoparticle contacts.
Collapse
Affiliation(s)
- Jeong-Seok Na
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA
| | | | | | | | | | | |
Collapse
|
33
|
Newton MD, Smalley JF. Interfacial bridge-mediated electron transfer: mechanistic analysis based on electrochemical kinetics and theoretical modelling. Phys Chem Chem Phys 2007; 9:555-72. [PMID: 17242737 DOI: 10.1039/b611448b] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Understanding the physical and chemical factors that control the kinetics of interfacial electron-transfer (ET) reactions is important for a large number of technological applications. The present article describes electrochemical kinetic studies of these factors, in which standard interfacial ET rate constants (k(0)(l)) have been measured for ET between substrate Au electrodes and various redox couples attached to the electrode surfaces by variable lengths (l) of oligomethylene (OM), oligophenylenevinylene (OPV) and oligophenyleneethynylene (OPE) bridges, which were constituents of mixed self-assembled monolayers (SAMs). The k(0)(l) measurements employed the indirect laser-induced temperature jump (ILIT) technique, which permits the measurement of interfacial ET rates that are orders of magnitude faster than those measurable by conventional techniques using the macroelectrodes that are the most convenient substrates for the mixed SAMs. The robustness of the measured rate constants (k(0)(l)), together with the Arrhenius activation energies (E(a)(l)) and preexponential factors (A(l)), is demonstrated by their invariance with respect to several experimental system parameters (including the chemical nature and length of the diluent component of the mixed SAM). Analysis of the kinetic results demonstrates that all of the observed interfacial ET processes proceed through a common type of transition state (predominantly associated with solvent reorganization around the redox moiety) and that the actual ET step involves direct electronic tunnelling between the Au electrode and the redox moiety. However, for the full range of l investigated, a global exponential decay of A(l) is not found for any of the three types of bridges. Possible reasons for this behavior, including the role of rate determining steps associated with adiabatic mechanisms within or beyond the transition state theory framework, are discussed, and comparisons with related conductance measurements are presented.
Collapse
Affiliation(s)
- Marshall D Newton
- Department of Chemistry, Brookhaven National Laboratory, Upton, NY 11973, USA.
| | | |
Collapse
|
34
|
Liang TT, Naitoh Y, Horikawa M, Ishida T, Mizutani W. Fabrication of Steady Junctions Consisting of α,ω-Bis(thioacetate) Oligo(p-phenylene vinylene)s in Nanogap Electrodes. J Am Chem Soc 2006; 128:13720-6. [PMID: 17044699 DOI: 10.1021/ja062561h] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
For obtaining molecular devices using metal-molecule-metal junctions, it is necessary to fabricate a steady conductive bridge-structure; that is stable chemical bonds need to be established from a single conductive molecule to two facing electrodes. In the present paper, we show that the steadiness of a conductive bridge-structure depends on the molecular structure of the bridge molecule for nanogap junctions using three types of modified oligo(phenylene vinylene)s (OPVs): alpha,omega-bis(thioacetate) oligo(phenylene vinylene) (OPV1), alpha,omega-bis(methylthioacetate) oligo(phenylene vinylene) (OPV2), and OPV2 consisting of ethoxy side chains (OPV3). We examined the change in resistance between the molecule-bridged junction and a bare junction in each of the experimental Au-OPV-Au junctions to confirm whether molecules formed steady bridges. Herein, the outcomes of whether molecules formed steady bridges were defined in terms of three types of result; successful, possible and failure. We define the ratio of the number of successful junctions to the total number of experimental junctions as successful rate. A 60% successful rate for OPV3 was higher than for the other two molecules whose successful rates were estimated to be approximately 10%. We propose that conjugated molecules consisting of methylthioacetate termini and short alkoxy side chains are well suited for fabricating a steady conductive bridge-structure between two facing electrodes.
Collapse
Affiliation(s)
- Tien-Tzu Liang
- Nanotechnology Research Institute, Tsukuba, Ibaraki 305-8562, Japan
| | | | | | | | | |
Collapse
|
35
|
Kushmerick JG, Blum AS, Long DP. Metrology for molecular electronics. Anal Chim Acta 2006; 568:20-7. [PMID: 17761242 DOI: 10.1016/j.aca.2005.12.033] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2005] [Revised: 11/23/2005] [Accepted: 12/05/2005] [Indexed: 11/16/2022]
Abstract
Building reliable molecular electronic devices requires the ability to accurately and reproducibly measure the electronic response of the system under study. Here we review our work with three distinct molecular electronic test structures which show excellent agreement for measurements on molecular wires and molecular switch molecules. We also discuss how inelastic electron tunneling spectroscopy enables chemical characterization of molecular electronic elements in actual device geometries.
Collapse
Affiliation(s)
- James G Kushmerick
- National Institute of Standards and Technology, Gaithersburg, MD 20899-8372, United States.
| | | | | |
Collapse
|
36
|
Jaiswal A, Tavakoli KG, Zou S. Coupled Surface-Enhanced Raman Spectroscopy and Electrical Conductivity Measurements of 1,4-Phenylene Diisocyanide in Molecular Electronic Junctions. Anal Chem 2005; 78:120-4. [PMID: 16383318 DOI: 10.1021/ac051318i] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Probing the structure of molecules in a metal-molecule-metal junction under an applied voltage is critical for understanding molecular electron transport properties. We present an approach that allows recording surface-enhanced Raman spectra simultaneously with electrical measurements of a monolayer of molecules in molecular electronic junctions. 1,4-Phenylene diisocyanide in two different types of junctions was used to illustrate the approach. The results show that the molecular integrity was intact in the molecular junctions and under the applied bias. The monolayer sensitivity of the approach provides a new powerful tool for characterizing molecular structure in a molecular electronic junction.
Collapse
Affiliation(s)
- Archana Jaiswal
- Department of Chemistry & Biochemistry, Center for Nanotechnology, Miami University, Oxford, Ohio 45056, USA
| | | | | |
Collapse
|
37
|
Seferos DS, Trammell SA, Bazan GC, Kushmerick JG. Probing pi-coupling in molecular junctions. Proc Natl Acad Sci U S A 2005; 102:8821-5. [PMID: 15956193 PMCID: PMC1157018 DOI: 10.1073/pnas.0500002102] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2005] [Indexed: 11/18/2022] Open
Abstract
Charge transport characteristics for metal-molecule-metal junctions containing two structurally related pi-conjugated systems were studied to probe pi-pi interactions in molecular junctions. The first molecule contains a typical pi-conjugated framework derived from phenylene vinylene units, whereas the second has the phenylene vinylene structure interrupted by a [2.2]paracyclophane (pCp) core. Electrochemical investigations were used to characterize the defects and packing density of self-assembled monolayers of the two molecules on gold surfaces and to enable quantitative comparison of their transport characteristics. Current-voltage measurements across molecular junctions containing the two species demonstrate that the pCp moiety yields a highly conductive break in through-bond pi-conjugation. The observed high conductivity is consistent with density functional theory calculations, which demonstrate strong through-space pi-pi coupling across the pCp moiety.
Collapse
Affiliation(s)
- Dwight S Seferos
- Department of Chemistry, Institute for Polymers and Organic Solids, University of California, Santa Barbara, CA 93106, USA
| | | | | | | |
Collapse
|
38
|
Abstract
The self-assembly of molecules into structurally organized monolayers (SAMs) uses the flexibility of organic chemistry and coordination chemistry to generate well-defined, synthetic surfaces with known molecular and macroscopic properties. The process of designing monolayers with a specified structure gives a high level of control over the molecular-level composition in the direction perpendicular to a surface; soft lithographic technique gives useful (if lower) resolution in the plane of the surface. Alkanethiolates adsorbed on gold, silver, mercury, palladium and platinum are currently the best-defined systems of SAMs. They provide substrates for a number of applications-from studies of wetting and electron transport to patterns for growing mammalian cells. SAMs have made organic surfaces a central part of surface science. Understanding the principles by which they form, and connecting molecular-level structure with macroscopic properties, opens a wide range of areas to study and exploitation.
Collapse
Affiliation(s)
- George M. Whitesides
- Harvard University, Department of Chemistry and Chemical Biology, 12 Oxford Street, Cambridge, MA 02138, USA
| | - Jennah K. Kriebel
- Harvard University, Department of Chemistry and Chemical Biology, 12 Oxford Street, Cambridge, MA 02138, USA
| | - J. Christopher Love
- Harvard Medical School, Department of Pathology, 200 Longwood Avenue, Building D2 – 1st Floor, Boston, MA 02115, USA
| |
Collapse
|
39
|
|