1
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Torabi N, Chiechi RC. Photosystem I complexes form remarkably stable self-assembled tunneling junctions. NANOSCALE 2024. [PMID: 39344694 DOI: 10.1039/d4nr02554g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/01/2024]
Abstract
This paper describes large-area molecular tunneling junctions comprising self-assembled monolayers (SAMs) of light-harvesting protein complexes using eutectic Ga-In (EGaIn) as a top contact. The complexes, which are readily isolable in large quantities from spinach leaves, self-assemble on top of SAMs of [6,6]-phenyl-C61-butyric acid (PCBA) on gold (Au) supported by mica substrates (AuMica), which induces them to adopt a preferred orientation with respect to the electron transport chain that runs across the short axis of each complex, leading to temperature-independent rectification. We compared trimeric protein complexes isolated from thermophilic cyanobacteria to monomeric complexes extracted from spinach leaves by measuring charge-transport at variable temperatures and over the course of at least three months. Transport is independent of temperature in the range of 130 to 310 K for both protein complexes, affirming that the likely mechanism is non-resonant tunneling. The junctions rectified current and were stable for at least three months when stored at room temperature in ambient conditions, with the yield of working junctions falling from 100% to 97% over that time. These results demonstrate a straightforward strategy for forming remarkably robust molecular junctions, avoiding the fragility that is common in molecular electronics.
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Affiliation(s)
- Nahid Torabi
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Ryan C Chiechi
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
- Department of Chemistry & Organic and Carbon Electronics Cluster, North Carolina State University, Raleigh, North Carolina 27695-8204, USA.
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2
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Rodríguez-Kessler PL, Muñoz-Castro A. Intermediate Intercluster Bond Orders. Electronic Communication in Au 38(SR) 24 Superatomic Molecules. Chemphyschem 2024; 25:e202400183. [PMID: 38831496 DOI: 10.1002/cphc.202400183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 04/23/2024] [Accepted: 06/03/2024] [Indexed: 06/05/2024]
Abstract
Ligand-protected gold clusters remain potential building blocks for envisaged molecular materials. The archetypal Au38(SR)24 cluster can be viewed as a robust template for the fusion of two Au25(SR)18 - cluster units, retaining a bi-icosahedral Au23 core. Via electrochemical properties, the overall charge state can be selectively tuned, enabling the access of 14 valence electron (ve) species featuring a single intercluster bond and nearby charge from -1 to +3, achieving related species bearing 15- to 11-ve with variable intercluster bond orders. Here, we explore the characteristics of intermediate intercluster bond orders in order to provide insights into the plausible electron communication between the constituent building blocks, with Au38(SR)24, as a representative template. Our results denote a small structural variation along -1 to +3 charge states, provided by the core-protecting ligand interaction, which is enhanced towards more oxidized species. The remaining unpaired electron from intermediate intercluster bond orders of 1.5 for Au38(SR)24 1-, 1.5 for Au38(SR)24 1+, and 2.5 for Au38(SR)24 3+, holds delocalized characteristics between the building block units, favoring electron communication for conductive and cooperative cluster aggregates. Such features are relevant for the formation of molecular electronic device applications, favoring the rationalization prior to engaging in explorative synthesis of larger ligand-protected cluster aggregates.
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Affiliation(s)
- Peter L Rodríguez-Kessler
- Centro de Investigaciones en Óptica A.C., Loma del Bosque 115, Col. Lomas del Campestre, León, Guanajuato, 37150, Mexico
| | - Alvaro Muñoz-Castro
- Facultad de Ingeniería, Arquitectura y Diseño, Universidad San Sebastián, Bellavista 7, Santiago, 8420524, Chile
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3
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Samajdar R, Meigooni M, Yang H, Li J, Liu X, Jackson NE, Mosquera MA, Tajkhorshid E, Schroeder CM. Secondary structure determines electron transport in peptides. Proc Natl Acad Sci U S A 2024; 121:e2403324121. [PMID: 39052850 PMCID: PMC11317557 DOI: 10.1073/pnas.2403324121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Accepted: 06/14/2024] [Indexed: 07/27/2024] Open
Abstract
Proteins play a key role in biological electron transport, but the structure-function relationships governing the electronic properties of peptides are not fully understood. Despite recent progress, understanding the link between peptide conformational flexibility, hierarchical structures, and electron transport pathways has been challenging. Here, we use single-molecule experiments, molecular dynamics (MD) simulations, nonequilibrium Green's function-density functional theory (NEGF-DFT), and unsupervised machine learning to understand the role of secondary structure on electron transport in peptides. Our results reveal a two-state molecular conductance behavior for peptides across several different amino acid sequences. MD simulations and Gaussian mixture modeling are used to show that this two-state molecular conductance behavior arises due to the conformational flexibility of peptide backbones, with a high-conductance state arising due to a more defined secondary structure (beta turn or 310 helices) and a low-conductance state occurring for extended peptide structures. These results highlight the importance of helical conformations on electron transport in peptides. Conformer selection for the peptide structures is rationalized using principal component analysis of intramolecular hydrogen bonding distances along peptide backbones. Molecular conformations from MD simulations are used to model charge transport in NEGF-DFT calculations, and the results are in reasonable qualitative agreement with experiments. Projected density of states calculations and molecular orbital visualizations are further used to understand the role of amino acid side chains on transport. Overall, our results show that secondary structure plays a key role in electron transport in peptides, which provides broad avenues for understanding the electronic properties of proteins.
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Affiliation(s)
- Rajarshi Samajdar
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL61801
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL61801
| | - Moeen Meigooni
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL61801
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL61801
| | - Hao Yang
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL61801
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL61801
| | - Jialing Li
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL61801
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL61801
| | - Xiaolin Liu
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL61801
| | - Nicholas E. Jackson
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL61801
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL61801
| | - Martín A. Mosquera
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT59717
| | - Emad Tajkhorshid
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL61801
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL61801
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL61801
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL61801
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL61801
| | - Charles M. Schroeder
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL61801
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL61801
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL61801
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL61801
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL61801
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL61801
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4
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Gorenskaia E, Low PJ. Methods for the analysis, interpretation, and prediction of single-molecule junction conductance behaviour. Chem Sci 2024; 15:9510-9556. [PMID: 38939131 PMCID: PMC11206205 DOI: 10.1039/d4sc00488d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 05/06/2024] [Indexed: 06/29/2024] Open
Abstract
This article offers a broad overview of measurement methods in the field of molecular electronics, with a particular focus on the most common single-molecule junction fabrication techniques, the challenges in data analysis and interpretation of single-molecule junction current-distance traces, and a summary of simulations and predictive models aimed at establishing robust structure-property relationships of use in the further development of molecular electronics.
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Affiliation(s)
- Elena Gorenskaia
- School of Molecular Sciences, University of Western Australia 35 Stirling Highway Crawley Western Australia 6026 Australia
| | - Paul J Low
- School of Molecular Sciences, University of Western Australia 35 Stirling Highway Crawley Western Australia 6026 Australia
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5
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Cossaboon TA, Kazmi S, Tineo M, Hoy EP. Assessing the importance of multireference correlation in predicting reversed conductance decay. Phys Chem Chem Phys 2024; 26:6696-6707. [PMID: 38321937 DOI: 10.1039/d3cp01110k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2024]
Abstract
In a classical electronic resistor, conductance decays as the device length increases according to Ohm's Law. While most molecular series display a comparable exponential decay in conductance with increasing molecular length, a class of single-molecule device series exists where conductance instead increases with molecular/device length, a phenomenon called reversed conductance decay. While reversals of conductance decay have been repeatedly theoretically predicted, they have been far more difficult to demonstrate experimentally. Previous studies have suggested that theoretical multi-reference(static) correlation errors may be a major cause of this discrepancy, yet most single-molecule transport methods are unable to treat multireference correlation. Using our unique multireference transport method based on non-equilibrium Green's function and multiconfigurational pair-density functional theory (NEGF-MCPDFT), we examined a previously predicted case of reversed conductance decay in systems of linear chains of phenyl rings with varying lengths and electrode designs. We compare our NEGF-MCPDFT results to those of non-multireference NEGF methods to quantify the exact role of static correlation in conductance decay reversals and clarify their relative importance to geometric and electrode design/coupling considerations.
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Affiliation(s)
- Tanner A Cossaboon
- Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ 08028, USA.
| | - Samir Kazmi
- Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ 08028, USA.
| | - Matthew Tineo
- Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ 08028, USA.
| | - Erik P Hoy
- Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ 08028, USA.
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6
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Reimers JR, Li T, Birvé AP, Yang L, Aragonès AC, Fallon T, Kosov DS, Darwish N. Controlling piezoresistance in single molecules through the isomerisation of bullvalenes. Nat Commun 2023; 14:6089. [PMID: 37789027 PMCID: PMC10547723 DOI: 10.1038/s41467-023-41674-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 09/06/2023] [Indexed: 10/05/2023] Open
Abstract
Nanoscale electro-mechanical systems (NEMS) displaying piezoresistance offer unique measurement opportunities at the sub-cellular level, in detectors and sensors, and in emerging generations of integrated electronic devices. Here, we show a single-molecule NEMS piezoresistor that operates utilising constitutional and conformational isomerisation of individual diaryl-bullvalene molecules and can be switched at 850 Hz. Observations are made using scanning tunnelling microscopy break junction (STMBJ) techniques to characterise piezoresistance, combined with blinking (current-time) experiments that follow single-molecule reactions in real time. A kinetic Monte Carlo methodology (KMC) is developed to simulate isomerisation on the experimental timescale, parameterised using density-functional theory (DFT) combined with non-equilibrium Green's function (NEGF) calculations. Results indicate that piezoresistance is controlled by both constitutional and conformational isomerisation, occurring at rates that are either fast (equilibrium) or slow (non-equilibrium) compared to the experimental timescale. Two different types of STMBJ traces are observed, one typical of traditional experiments that are interpreted in terms of intramolecular isomerisation occurring on stable tipped-shaped metal-contact junctions, and another attributed to arise from junction‒interface restructuring induced by bullvalene isomerisation.
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Affiliation(s)
- Jeffrey R Reimers
- International Centre for Quantum and Molecular Structures and the Department of Physics, Shanghai University, Shanghai, 200444, China.
- School of Mathematical and Physical Sciences, University of Technology Sydney, Sydney, NSW, 2007, Australia.
| | - Tiexin Li
- School of Molecular and Life Sciences, Curtin University, Bentley, WA, 6102, Australia
| | - André P Birvé
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, 2308, Australia
| | - Likun Yang
- International Centre for Quantum and Molecular Structures and the Department of Physics, Shanghai University, Shanghai, 200444, China
| | - Albert C Aragonès
- Department of Materials Science and Physical Chemistry, University of Barcelona, Marti i Franquès 1, 08028, Barcelona, Catalonia, Spain
- Institute of Theoretical and Computational Chemistry, University of Barcelona, Diagonal 645, 08028, Barcelona, Catalonia, Spain
| | - Thomas Fallon
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, 2308, Australia.
| | - Daniel S Kosov
- College of Science and Engineering, James Cook University, Townsville, QLD, 4811, Australia.
| | - Nadim Darwish
- School of Molecular and Life Sciences, Curtin University, Bentley, WA, 6102, Australia.
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7
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Dumont R, Dowdell J, Song J, Li J, Wang S, Kang W, Li B. Control of charge transport in electronically active systems towards integrated biomolecular circuits (IbC). J Mater Chem B 2023; 11:8302-8314. [PMID: 37464922 DOI: 10.1039/d3tb00701d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2023]
Abstract
The miniaturization of traditional silicon-based electronics will soon reach its limitation as quantum tunneling and heat become serious problems at the several-nanometer scale. Crafting integrated circuits via self-assembly of electronically active molecules using a "bottom-up" paradigm provides a potential solution to these technological challenges. In particular, integrated biomolecular circuits (IbC) offer promising advantages to achieve this goal, as nature offers countless examples of functionalities entailed by self-assembly and examples of controlling charge transport at the molecular level within the self-assembled structures. To this end, the review summarizes the progress in understanding how charge transport is regulated in biosystems and the key redox-active amino acids that enable the charge transport. In addition, charge transport mechanisms at different length scales are also reviewed, offering key insights for controlling charge transport in IbC in the future.
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Affiliation(s)
- Ryan Dumont
- Department of Mechanical Engineering, Kennesaw State University, Marietta, GA, USA.
| | - Juwaan Dowdell
- Department of Mechanical Engineering, Kennesaw State University, Marietta, GA, USA.
| | - Jisoo Song
- Department of Mechanical Engineering, Kennesaw State University, Marietta, GA, USA.
| | - Jiani Li
- State Key Laboratory of Fine Chemicals, Frontiers Science Centre for Smart Materials Oriented Chemical Engineering, School of Bioengineering, Dalian University of Technology, Dalian, China.
| | - Suwan Wang
- State Key Laboratory of Fine Chemicals, Frontiers Science Centre for Smart Materials Oriented Chemical Engineering, School of Bioengineering, Dalian University of Technology, Dalian, China.
| | - Wei Kang
- State Key Laboratory of Fine Chemicals, Frontiers Science Centre for Smart Materials Oriented Chemical Engineering, School of Bioengineering, Dalian University of Technology, Dalian, China.
- Ningbo Institute of Dalian University of Technology, Ningbo, China
| | - Bo Li
- Department of Mechanical Engineering, Kennesaw State University, Marietta, GA, USA.
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8
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Pabi B, Marek Š, Pal A, Kumari P, Ray SJ, Thakur A, Korytár R, Pal AN. Resonant transport in a highly conducting single molecular junction via metal-metal covalent bond. NANOSCALE 2023; 15:12995-13008. [PMID: 37483089 DOI: 10.1039/d3nr02585c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/25/2023]
Abstract
Achieving highly transmitting molecular junctions through resonant transport at low bias is key to the next-generation low-power molecular devices. Although resonant transport in molecular junctions was observed by connecting a molecule between the metal electrodes via chemical anchors by applying a high source-drain bias (>1 V), the conductance was limited to <0.1G0, G0 being the quantum of conductance. Herein, we report electronic transport measurements by directly connecting a ferrocene molecule between Au electrodes under ambient conditions in a mechanically controllable break junction setup (MCBJ), revealing a conductance peak at ∼0.2G0 in the conductance histogram. A similar experiment was repeated for ferrocene terminated with amine (-NH2) and cyano (-CN) anchors, where conductance histograms exhibit an extended low conductance feature, including the sharp high conductance peak, similar to pristine ferrocene. The statistical analysis of the data and density functional theory-based transport calculation suggest a possible molecular conformation with a strong hybridization between the Au electrodes, and that the Fe atom of ferrocene is responsible for a near-perfect transmission in the vicinity of the Fermi energy, leading to the resonant transport at a small applied bias (<0.5 V). Moreover, calculations including van der Waals/dispersion corrections reveal a covalent-like organometallic bonding between Au and the central Fe atom of ferrocene, having bond energies of ∼660 meV. Overall, our study not only demonstrates the realization of an air-stable highly transmitting molecular junction, but also provides important insights about the nature of chemical bonding at the metal/organo-metallic interface.
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Affiliation(s)
- Biswajit Pabi
- Department of Condensed Matter and Materials Physics, S. N. Bose National Centre for Basic Sciences, Sector III, Block JD, Salt Lake, Kolkata 700106, India.
| | - Štepán Marek
- Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, 121 16, Prague 2, Czech Republic
| | - Adwitiya Pal
- Department of Chemistry, Jadavpur University, Kolkata-700032, India
| | - Puja Kumari
- Department of Physics, Indian Institute of Technology Patna, Bihar-801106, India
| | - Soumya Jyoti Ray
- Department of Physics, Indian Institute of Technology Patna, Bihar-801106, India
| | - Arunabha Thakur
- Department of Chemistry, Jadavpur University, Kolkata-700032, India
| | - Richard Korytár
- Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, 121 16, Prague 2, Czech Republic
| | - Atindra Nath Pal
- Department of Condensed Matter and Materials Physics, S. N. Bose National Centre for Basic Sciences, Sector III, Block JD, Salt Lake, Kolkata 700106, India.
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9
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Liu H, Chen L, Zhang H, Yang Z, Ye J, Zhou P, Fang C, Xu W, Shi J, Liu J, Yang Y, Hong W. Single-molecule photoelectron tunnelling spectroscopy. NATURE MATERIALS 2023; 22:1007-1012. [PMID: 37349394 DOI: 10.1038/s41563-023-01591-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 05/25/2023] [Indexed: 06/24/2023]
Abstract
Experimental mapping of transmission is essential for understanding and controlling charge transport through molecular devices and materials. Here we developed a single-molecule photoelectron tunnelling spectroscopy approach for mapping transmission beyond the HOMO-LUMO gap of the single diketopyrrolopyrrole molecule junction using an ultrafast-laser combined scanning tunnelling microscope-based break junction set-up at room temperature. Two resonant transport channels of ultrafast photocurrent are found by our photoelectron tunnelling spectroscopy, ranging from 1.31 eV to 1.77 eV, consistent with the LUMO + 1 and LUMO + 2 in the transmission spectrum obtained by density functional theory calculations. Moreover, we observed the modulation of resonant peaks by varying bias voltages, which demonstrates the ability to quantitatively characterize the effect of the electric field on frontier molecular orbitals. Our single-molecule photoelectron tunnelling spectroscopy offers an avenue that allows us to explore the nature of energy-dependent charge transport through single-molecule junctions.
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Affiliation(s)
- Haojie Liu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen, China
| | - Lijue Chen
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen, China
| | - Hao Zhang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen, China
| | - Zhangqiang Yang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen, China
| | - Jingyao Ye
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen, China
| | - Ping Zhou
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen, China
| | - Chao Fang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen, China
| | - Wei Xu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen, China
| | - Jia Shi
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen, China
| | - Junyang Liu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen, China
| | - Ye Yang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen, China
| | - Wenjing Hong
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen, China.
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10
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Tan Y, Li J, Li S, Yang H, Chi T, Shiring SB, Liu K, Savoie BM, Boudouris BW, Schroeder CM. Enhanced Electron Transport in Nonconjugated Radical Oligomers Occurs by Tunneling. NANO LETTERS 2023. [PMID: 37384632 DOI: 10.1021/acs.nanolett.3c00978] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/01/2023]
Abstract
Incorporating temperature- and air-stable organic radical species into molecular designs is a potentially advantageous means of controlling the properties of electronic materials. However, we still lack a complete understanding of the structure-property relationships of organic radical species at the molecular level. In this work, the charge transport properties of (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) radical-containing nonconjugated molecules are studied using single-molecule charge transport experiments and molecular modeling. Importantly, the TEMPO pendant groups promote temperature-independent molecular charge transport in the tunneling region relative to the quenched and closed-shell phenyl pendant groups. Results from molecular modeling show that the TEMPO radicals interact with the gold metal electrodes near the interface to facilitate a high-conductance conformation. Overall, the large enhancement of charge transport by incorporation of open-shell species into a single nonconjugated molecular component opens exciting avenues for implementing molecular engineering in the development of next-generation electronic devices based on novel nonconjugated radical materials.
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Affiliation(s)
- Ying Tan
- Charles D. Davidson School of Chemical Engineering, Purdue University, 480 Stadium Avenue, West Lafayette, Indiana 47907, United States
| | - Jialing Li
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Joint Center for Energy Storage Research, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, Illinois 60439, United States
| | - Songsong Li
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Joint Center for Energy Storage Research, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, Illinois 60439, United States
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Hao Yang
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Teng Chi
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
| | - Stephen B Shiring
- Charles D. Davidson School of Chemical Engineering, Purdue University, 480 Stadium Avenue, West Lafayette, Indiana 47907, United States
| | - Kangying Liu
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
| | - Brett M Savoie
- Charles D. Davidson School of Chemical Engineering, Purdue University, 480 Stadium Avenue, West Lafayette, Indiana 47907, United States
| | - Bryan W Boudouris
- Charles D. Davidson School of Chemical Engineering, Purdue University, 480 Stadium Avenue, West Lafayette, Indiana 47907, United States
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
| | - Charles M Schroeder
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Joint Center for Energy Storage Research, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, Illinois 60439, United States
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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11
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Li T, Bandari VK, Schmidt OG. Molecular Electronics: Creating and Bridging Molecular Junctions and Promoting Its Commercialization. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2209088. [PMID: 36512432 DOI: 10.1002/adma.202209088] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 11/28/2022] [Indexed: 06/02/2023]
Abstract
Molecular electronics is driven by the dream of expanding Moore's law to the molecular level for next-generation electronics through incorporating individual or ensemble molecules into electronic circuits. For nearly 50 years, numerous efforts have been made to explore the intrinsic properties of molecules and develop diverse fascinating molecular electronic devices with the desired functionalities. The flourishing of molecular electronics is inseparable from the development of various elegant methodologies for creating nanogap electrodes and bridging the nanogap with molecules. This review first focuses on the techniques for making lateral and vertical nanogap electrodes by breaking, narrowing, and fixed modes, and highlights their capabilities, applications, merits, and shortcomings. After summarizing the approaches of growing single molecules or molecular layers on the electrodes, the methods of constructing a complete molecular circuit are comprehensively grouped into three categories: 1) directly bridging one-molecule-electrode component with another electrode, 2) physically bridging two-molecule-electrode components, and 3) chemically bridging two-molecule-electrode components. Finally, the current state of molecular circuit integration and commercialization is discussed and perspectives are provided, hoping to encourage the community to accelerate the realization of fully scalable molecular electronics for a new era of integrated microsystems and applications.
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Affiliation(s)
- Tianming Li
- Research Center for Materials, Architectures and Integration of Nanomembranes (MAIN), Chemnitz University of Technology, 09126, Chemnitz, Germany
- Material Systems for Nanoelectronics, Chemnitz University of Technology, 09111, Chemnitz, Germany
| | - Vineeth Kumar Bandari
- Research Center for Materials, Architectures and Integration of Nanomembranes (MAIN), Chemnitz University of Technology, 09126, Chemnitz, Germany
- Material Systems for Nanoelectronics, Chemnitz University of Technology, 09111, Chemnitz, Germany
| | - Oliver G Schmidt
- Research Center for Materials, Architectures and Integration of Nanomembranes (MAIN), Chemnitz University of Technology, 09126, Chemnitz, Germany
- Material Systems for Nanoelectronics, Chemnitz University of Technology, 09111, Chemnitz, Germany
- Nanophysics, Dresden University of Technology, 01069, Dresden, Germany
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12
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Gorenskaia E, Potter J, Korb M, Lambert C, Low PJ. Exploring relationships between chemical structure and molecular conductance: from α,ω-functionalised oligoynes to molecular circuits. NANOSCALE 2023. [PMID: 37070423 DOI: 10.1039/d3nr01034a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
The quantum circuit rule (QCR) allows estimation of the conductance of molecular junctions, electrode|X-bridge-Y|electrode, by considering the molecule as a series of independent scattering regions associated with the anchor groups (X, Y) and bridge, provided the numerical parameters that characterise the anchor groups (aX, aY) and molecular backbones (bB) are known. Single-molecule conductance measurements made with a series of α,ω-substituted oligoynes (X-{(CC)N}-X, N = 1, 2, 3, 4), functionalised by terminal groups, X (4-thioanisole (C6H4SMe), 5-(3,3-dimethyl-2,3-dihydrobenzo[b]thiophene) (DMBT), 4-aniline (C6H4NH2), 4-pyridine (Py), capable of serving as 'anchor groups' to contact the oligoyne fragment within a molecular junction, have shown the expected exponential dependence of molecular conductance, G, with the number of alkyne repeating units. In turn, this allows estimation of the anchor (ai) and backbone (bi) parameters. Using these values, together with previously determined parameters for other molecular fragments, the QCR is found to accurately estimate the junction conductance of more complex molecular circuits formed from smaller components assembled in series.
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Affiliation(s)
- Elena Gorenskaia
- School of Molecular Sciences, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia, 6026, Australia.
| | - Jarred Potter
- School of Molecular Sciences, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia, 6026, Australia.
| | - Marcus Korb
- School of Molecular Sciences, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia, 6026, Australia.
| | - Colin Lambert
- Department of Physics, University of Lancaster, Lancaster LA1 4YB, England, UK.
| | - Paul J Low
- School of Molecular Sciences, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia, 6026, Australia.
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13
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Mang A, Rotthowe N, Beltako K, Linseis M, Pauly F, Winter RF. Single-molecule conductance studies on quasi- and metallaaromatic dibenzoylmethane coordination compounds and their aromatic analogs. NANOSCALE 2023; 15:5305-5316. [PMID: 36811332 DOI: 10.1039/d2nr05670d] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The ability to predict the conductive behaviour of molecules, connected to macroscopic electrodes, represents a crucial prerequisite for the design of nanoscale electronic devices. In this work, we investigate whether the notion of a negative relation between conductance and aromaticity (the so-called NRCA rule) also pertains to quasi-aromatic and metallaaromatic chelates derived from dibenzoylmethane (DBM) and Lewis acids (LAs) that either do or do not contribute two extra dπ electrons to the central resonance-stabilised β-ketoenolate binding pocket. We therefore synthesised a family of methylthio-functionalised DBM coordination compounds and subjected them, along with their truly aromatic terphenyl and 4,6-diphenylpyrimidine congeners, to scanning tunneling microscope break-junction (STM-BJ) experiments on gold nanoelectrodes. All molecules share the common motif of three π-conjugated, six-membered, planar rings with a meta-configuration at the central ring. According to our results, their molecular conductances fall within a factor of ca. 9 in an ordering aromatic < metallaaromatic < quasi-aromatic. The experimental trends are rationalised by quantum transport calculations based on density functional theory (DFT).
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Affiliation(s)
- André Mang
- Chemistry Department, University of Konstanz, 78457 Konstanz, Germany.
| | - Nils Rotthowe
- Chemistry Department, University of Konstanz, 78457 Konstanz, Germany.
| | - Katawoura Beltako
- Physics Department, University of Lomé, 1515 Lomé, Togo
- Institute of Physics, University of Augsburg, 86159 Augsburg, Germany.
| | - Michael Linseis
- Chemistry Department, University of Konstanz, 78457 Konstanz, Germany.
| | - Fabian Pauly
- Institute of Physics, University of Augsburg, 86159 Augsburg, Germany.
| | - Rainer F Winter
- Chemistry Department, University of Konstanz, 78457 Konstanz, Germany.
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14
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Using automated synthesis to understand the role of side chains on molecular charge transport. Nat Commun 2022; 13:2102. [PMID: 35440635 PMCID: PMC9019014 DOI: 10.1038/s41467-022-29796-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 03/22/2022] [Indexed: 11/21/2022] Open
Abstract
The development of next-generation organic electronic materials critically relies on understanding structure-function relationships in conjugated polymers. However, unlocking the full potential of organic materials requires access to their vast chemical space while efficiently managing the large synthetic workload to survey new materials. In this work, we use automated synthesis to prepare a library of conjugated oligomers with systematically varied side chain composition followed by single-molecule characterization of charge transport. Our results show that molecular junctions with long alkyl side chains exhibit a concentration-dependent bimodal conductance with an unexpectedly high conductance state that arises due to surface adsorption and backbone planarization, which is supported by a series of control experiments using asymmetric, planarized, and sterically hindered molecules. Density functional theory simulations and experiments using different anchors and alkoxy side chains highlight the role of side chain chemistry on charge transport. Overall, this work opens new avenues for using automated synthesis for the development and understanding of organic electronic materials. Development of organic electronic materials relies on understanding structure-function relationships in conjugated polymers but the synthetic workload to make large numbers of new compounds presents a practical barrier to properly survey conjugated organic derivatives. Here, the authors use automated synthesis to prepare a library of conjugated oligomers with systematically varied side chain composition followed by single-molecule characterization of charge transport.
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15
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Roy P, Pramanik A, Sarkar P. Polaron Induced Conductance Switching in Conjugated Oligophenylene: A First-Principles Analysis. J Phys Chem A 2022; 126:318-324. [PMID: 34985265 DOI: 10.1021/acs.jpca.1c10548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
For π-conjugated systems, polaron formation has a major impact on their optoelectronic properties. In fact, for such systems, an exquisite interplay between electron delocalization and the steric effect determines their ground state properties. However, an excess charge (positive or negative) injection causes structural reorientation because of extended conjugation. Herein, we investigate the effect of such an excess charge in an individual polyphenylene on its quantum conductance behavior. By combining the DFT and NEGF formalisms, we characterize both structural and electronic changes occurring upon electron and hole injection. We demonstrate that for both the cationic and anionic radicals, the excess charge is observed to be localized, inducing a partial planarization of the molecule and forming cationic and anionic polarons, respectively. The calculated low-bias conductance values determine the polaronic effect and could be implemented for easy determination and measurement of polaron formation. In fact, cationic and anionic polarons induce a large degree of conductance switching, involving a decrease and increase of conductance, respectively.
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Affiliation(s)
- Prodyut Roy
- Department of Chemistry, Visva-Bharati University, Santiniketan 731235, India
| | - Anup Pramanik
- Department of Chemistry, Sidho-Kanho-Birsha University, Purulia 723104, India
| | - Pranab Sarkar
- Department of Chemistry, Visva-Bharati University, Santiniketan 731235, India
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