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Xu X, Gao C, Emusani R, Jia C, Xiang D. Toward Practical Single-Molecule/Atom Switches. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2400877. [PMID: 38810145 PMCID: PMC11304318 DOI: 10.1002/advs.202400877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 04/29/2024] [Indexed: 05/31/2024]
Abstract
Electronic switches have been considered to be one of the most important components of contemporary electronic circuits for processing and storing digital information. Fabricating functional devices with building blocks of atomic/molecular switches can greatly promote the minimization of the devices and meet the requirement of high integration. This review highlights key developments in the fabrication and application of molecular switching devices. This overview offers valuable insights into the switching mechanisms under various stimuli, emphasizing structural and energy state changes in the core molecules. Beyond the molecular switches, typical individual metal atomic switches are further introduced. A critical discussion of the main challenges for realizing and developing practical molecular/atomic switches is provided. These analyses and summaries will contribute to a comprehensive understanding of the switch mechanisms, providing guidance for the rational design of functional nanoswitch devices toward practical applications.
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Affiliation(s)
- Xiaona Xu
- Institute of Modern Optics and Center of Single Molecule SciencesNankai UniversityTianjin Key Laboratory of Micro‐scale Optical Information Science and TechnologyTianjin300350China
| | - Chunyan Gao
- Institute of Modern Optics and Center of Single Molecule SciencesNankai UniversityTianjin Key Laboratory of Micro‐scale Optical Information Science and TechnologyTianjin300350China
| | - Ramya Emusani
- Institute of Modern Optics and Center of Single Molecule SciencesNankai UniversityTianjin Key Laboratory of Micro‐scale Optical Information Science and TechnologyTianjin300350China
| | - Chuancheng Jia
- Institute of Modern Optics and Center of Single Molecule SciencesNankai UniversityTianjin Key Laboratory of Micro‐scale Optical Information Science and TechnologyTianjin300350China
| | - Dong Xiang
- Institute of Modern Optics and Center of Single Molecule SciencesNankai UniversityTianjin Key Laboratory of Micro‐scale Optical Information Science and TechnologyTianjin300350China
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2
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Chen Y, Bâldea I, Yu Y, Liang Z, Li MD, Koren E, Xie Z. CP-AFM Molecular Tunnel Junctions with Alkyl Backbones Anchored Using Alkynyl and Thiol Groups: Microscopically Different Despite Phenomenological Similarity. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:4410-4423. [PMID: 38348971 PMCID: PMC10906003 DOI: 10.1021/acs.langmuir.3c03759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 01/24/2024] [Accepted: 01/24/2024] [Indexed: 02/28/2024]
Abstract
In this paper, we report results on the electronic structure and transport properties of molecular junctions fabricated via conducting probe atomic force microscopy (CP-AFM) using self-assembled monolayers (SAMs) of n-alkyl chains anchored with acetylene groups (CnA; n = 8, 9, 10, and 12) on Ag, Au, and Pt electrodes. We found that the current-voltage (I-V) characteristics of CnA CP-AFM junctions can be very accurately reproduced by the same off-resonant single-level model (orSLM) successfully utilized previously for many other junctions. We demonstrate that important insight into the energy-level alignment can be gained from experimental data of transport (processed via the orSLM) and ultraviolet photoelectron spectroscopy combined with ab initio quantum chemical information based on the many-body outer valence Green's function method. Measured conductance GAg < GAu < GPt is found to follow the same ordering as the metal work function ΦAu < ΦAu < ΦPt, a fact that points toward a transport mediated by an occupied molecular orbital (MO). Still, careful data analysis surprisingly revealed that transport is not dominated by the ubiquitous HOMO but rather by the HOMO-1. This is an important difference from other molecular tunnel junctions with p-type HOMO-mediated conduction investigated in the past, including the alkyl thiols (CnT) to which we refer in view of some similarities. Furthermore, unlike in CnT and other junctions anchored with thiol groups investigated in the past, the AFM tip causes in CnA an additional MO shift, whose independence of size (n) rules out significant image charge effects. Along with the prevalence of the HOMO-1 over the HOMO, the impact of the "second" (tip) electrode on the energy level alignment is another important finding that makes the CnA and CnT junctions different. What ultimately makes CnA unique at the microscopic level is a salient difference never reported previously, namely, that CnA's alkyne functional group gives rise to two energetically close (HOMO and HOMO-1) orbitals. This distinguishes the present CnA from the CnT, whose HOMO stemming from its thiol group is well separated energetically from the other MOs.
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Affiliation(s)
- Yuhong Chen
- Department
of Materials Science and Engineering, Technion-Israel
Institute of Technology, Haifa 3200003, Israel
- Department
of Materials Science and Engineering, Guangdong Provincial Key Laboratory
of Materials and Technologies for Energy Conversion (MATEC), Guangdong Technion-Israel Institute of Technology, 241 Daxue Road, Shantou, Guangdong 515063, China
| | - Ioan Bâldea
- Theoretical
Chemistry, Heidelberg University, Im Neuenheimer Feld 229, D-69120 Heidelberg, Germany
| | - Yongxin Yu
- Department
of Materials Science and Engineering, Guangdong Provincial Key Laboratory
of Materials and Technologies for Energy Conversion (MATEC), Guangdong Technion-Israel Institute of Technology, 241 Daxue Road, Shantou, Guangdong 515063, China
| | - Zining Liang
- Department
of Materials Science and Engineering, Guangdong Provincial Key Laboratory
of Materials and Technologies for Energy Conversion (MATEC), Guangdong Technion-Israel Institute of Technology, 241 Daxue Road, Shantou, Guangdong 515063, China
| | - Ming-De Li
- Department
of Chemistry and Key Laboratory for Preparation and Application of
Ordered Structural Materials of Guangdong Province, Shantou University, Shantou 515063, China
| | - Elad Koren
- Department
of Materials Science and Engineering, Technion-Israel
Institute of Technology, Haifa 3200003, Israel
| | - Zuoti Xie
- Department
of Materials Science and Engineering, Technion-Israel
Institute of Technology, Haifa 3200003, Israel
- Department
of Materials Science and Engineering, Guangdong Provincial Key Laboratory
of Materials and Technologies for Energy Conversion (MATEC), Guangdong Technion-Israel Institute of Technology, 241 Daxue Road, Shantou, Guangdong 515063, China
- Quantum
Science Center of Guangdong-Hong Kong-Macao Greater Bay Area (Guangdong), Shenzhen-Hong Kong International Science and Technology
Park, No. 3 Binglang
Road, Futian District, Shenzhen, Guangdong 518048, China
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3
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Escorihuela E, Del Barrio J, Davidson RJ, Beeby A, Low PJ, Prez-Murano F, Cea P, Martin S. Large area arrays of discrete single-molecule junctions derived from host-guest complexes. NANOSCALE 2024; 16:1238-1246. [PMID: 38116590 DOI: 10.1039/d3nr05122f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2023]
Abstract
The desire to continually reduce the lower limits of semiconductor integrated circuit (IC) fabrication methods continues to inspire interest in unimolecular electronics as a platform technology for the realization of future (opto)electronic devices. However, despite successes in developing methods for the construction and measurement of single-molecule and large-area molecular junctions, exercising control over the precise junction geometry remains a significant challenge. Here, host-guest complexes of the wire-like viologen derivative 1,1'-bis(4-(methylthio)-phenyl)-[4,4'-bipyridine]-1,1'-diium chloride ([1][Cl]2) and cucurbit[7]uril (CB[7]) have been self-assembled in a regular pattern over a gold substrate. Subsequently, ligandless gold nanoparticles (AuNPs) synthesized in situ are deposited over the host-guest array. The agreement between the conductance of individual mono-molecular junctions, appropriately chosen as a function of the AuNP diameter, within this array determined by conductive probe atomic force microscope (c-AFM) and true single-molecule measurements for a closely similar host-guest complex within a scanning tunneling microscope break-junction (STM-BJ) indicates the formation of molecular junctions derived from these host-guest complexes without deleterious intermolecular coupling effects.
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Affiliation(s)
- Enrique Escorihuela
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009, Zaragoza, Spain.
- Departamento de Química Física, Universidad de Zaragoza, 50009, Zaragoza, Spain
| | - Jesús Del Barrio
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009, Zaragoza, Spain.
- Departamento de Química Orgánica, Universidad de Zaragoza, 50009, Zaragoza, Spain
| | - Ross J Davidson
- Department of Chemistry, Durham University, South Rd, Durham, DH1 3LE, UK
| | - Andrew Beeby
- Department of Chemistry, Durham University, South Rd, Durham, DH1 3LE, UK
| | - Paul J Low
- School of Molecular Sciences, University of Western Australia, 35 Stirling Highway, Crawley, 6009, Western Australia, Australia
| | - Francesc Prez-Murano
- Institute of Microelectronics of Barcelona (IMB-CNM, CSIC), 08193, Bellaterra, Spain
| | - Pilar Cea
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009, Zaragoza, Spain.
- Departamento de Química Física, Universidad de Zaragoza, 50009, Zaragoza, Spain
- Laboratorio de Microscopias Avanzadas (LMA), Universidad de Zaragoza, 50018, Zaragoza, Spain
| | - Santiago Martin
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009, Zaragoza, Spain.
- Departamento de Química Física, Universidad de Zaragoza, 50009, Zaragoza, Spain
- Laboratorio de Microscopias Avanzadas (LMA), Universidad de Zaragoza, 50018, Zaragoza, Spain
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4
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Therssen H, Catala L, Mazérat S, Mallah T, Vuillaume D, Mélin T, Lenfant S. Electronic properties of single Prussian Blue Analog nanocrystals determined by conductive-AFM. NANOSCALE 2023; 15:19128-19138. [PMID: 37964732 DOI: 10.1039/d3nr04542k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2023]
Abstract
We report a study of the electron transport (ET) properties at the nanoscale (conductive-AFM denoted as C-AFM hereafter) of individual Prussian Blue Analog (PBA) cubic nanocrystals (NCs) of CsCoIIIFeII, with a size between 15 and 50 nm deposited on HOPG. We demonstrate that these PBA NCs feature an almost size-independent electron injection barrier of 0.41 ± 0.02 eV and 0.27 ± 0.03 eV at the CsCoIIIFeII/HOPG and CsCoIIIFeII/C-AFM tip, respectively, and an intrinsic electron conductivity evolving from a large dispersion between ∼5 × 10-4 and 2 × 10-2 S cm-1 without a clear correlation with the nanocrystal size. The conductivity values measured on individual nanocrystals are up to fifty times higher than those reported on PBA films.
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Affiliation(s)
- Hugo Therssen
- Univ. Lille, CNRS, Univ. Polytechnique Hauts-de-France, UMR 8520 - IEMN - Institut d'Electronique de Microélectronique et de Nanotechnologie, F-59000 Lille, France.
| | - Laure Catala
- Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), CNRS, Université Paris-Saclay, 91400 Orsay Cedex, France
| | - Sandra Mazérat
- Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), CNRS, Université Paris-Saclay, 91400 Orsay Cedex, France
| | - Talal Mallah
- Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), CNRS, Université Paris-Saclay, 91400 Orsay Cedex, France
| | - Dominique Vuillaume
- Univ. Lille, CNRS, Univ. Polytechnique Hauts-de-France, UMR 8520 - IEMN - Institut d'Electronique de Microélectronique et de Nanotechnologie, F-59000 Lille, France.
| | - Thierry Mélin
- Univ. Lille, CNRS, Univ. Polytechnique Hauts-de-France, UMR 8520 - IEMN - Institut d'Electronique de Microélectronique et de Nanotechnologie, F-59000 Lille, France.
| | - Stéphane Lenfant
- Univ. Lille, CNRS, Univ. Polytechnique Hauts-de-France, UMR 8520 - IEMN - Institut d'Electronique de Microélectronique et de Nanotechnologie, F-59000 Lille, France.
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5
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Lu B, Vegso K, Micky S, Ritz C, Bodik M, Fedoryshyn YM, Siffalovic P, Stemmer A. Tunable Subnanometer Gaps in Self-Assembled Monolayer Gold Nanoparticle Superlattices Enabling Strong Plasmonic Field Confinement. ACS NANO 2023. [PMID: 37354449 DOI: 10.1021/acsnano.3c03804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2023]
Abstract
Nanoparticle superlattices produced with controllable interparticle gap distances down to the subnanometer range are of superior significance for applications in electronic and plasmonic devices as well as in optical metasurfaces. In this work, a method to fabricate large-area (∼1 cm2) gold nanoparticle (GNP) superlattices with a typical size of single domains at several micrometers and high-density nanogaps of tunable distances (from 2.3 to 0.1 nm) as well as variable constituents (from organothiols to inorganic S2-) is demonstrated. Our approach is based on the combination of interfacial nanoparticle self-assembly, subphase exchange, and free-floating ligand exchange. Electrical transport measurements on our GNP superlattices reveal variations in the nanogap conductance of more than 6 orders of magnitude. Meanwhile, nanoscopic modifications in the surface potential landscape of active GNP devices have been observed following engineered nanogaps. In situ optical reflectance measurements during free-floating ligand exchange show a gradual enhancement of plasmonic capacitive coupling with a diminishing average interparticle gap distance down to 0.1 nm, as continuously red-shifted localized surface plasmon resonances with increasing intensity have been observed. Optical metasurfaces consisting of such GNP superlattices exhibit tunable effective refractive index over a broad wavelength range. Maximal real part of the effective refractive index, nmax, reaching 5.4 is obtained as a result of the extreme field confinement in the high-density subnanometer plasmonic gaps.
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Affiliation(s)
- Bin Lu
- Nanotechnology Group, ETH Zürich, Säumerstasse 4, CH-8803 Rüschlikon, Switzerland
| | - Karol Vegso
- Institute of Physics SAS, Dubravska cesta 9, 84511 Bratislava, Slovakia
| | - Simon Micky
- Institute of Physics SAS, Dubravska cesta 9, 84511 Bratislava, Slovakia
| | - Christian Ritz
- Nanotechnology Group, ETH Zürich, Säumerstasse 4, CH-8803 Rüschlikon, Switzerland
| | - Michal Bodik
- Nanotechnology Group, ETH Zürich, Säumerstasse 4, CH-8803 Rüschlikon, Switzerland
| | | | - Peter Siffalovic
- Institute of Physics SAS, Dubravska cesta 9, 84511 Bratislava, Slovakia
| | - Andreas Stemmer
- Nanotechnology Group, ETH Zürich, Säumerstasse 4, CH-8803 Rüschlikon, Switzerland
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6
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Lokamani M, Kilibarda F, Günther F, Kelling J, Strobel A, Zahn P, Juckeland G, Gothelf KV, Scheer E, Gemming S, Erbe A. Stretch Evolution of Electronic Coupling of the Thiophenyl Anchoring Group with Gold in Mechanically Controllable Break Junctions. J Phys Chem Lett 2023:5709-5717. [PMID: 37318265 DOI: 10.1021/acs.jpclett.3c00370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The current-voltage characteristics of a single-molecule junction are determined by the electronic coupling Γ between the electronic states of the electrodes and the dominant transport channel(s) of the molecule. Γ is profoundly affected by the choice of the anchoring groups and their binding positions on the tip facets and the tip-tip separation. In this work, mechanically controllable break junction experiments on the N,N'-bis(5-ethynylbenzenethiol-salicylidene)ethylenediamine are presented, in particular, the stretch evolution of Γ with increasing tip-tip separation. The stretch evolution of Γ is characterized by recurring local maxima and can be related to the deformation of the molecule and sliding of the anchoring groups above the tip facets and along the tip edges. A dynamic simulation approach is implemented to model the stretch evolution of Γ, which captures the experimentally observed features remarkably well and establishes a link to the microscopic structure of the single-molecule junction.
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Affiliation(s)
- Mani Lokamani
- Department of Information Services and Computing, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Bautzner Landstraße 400, 01328 Dresden, Germany
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Bautzner Landstraße 400, 01328 Dresden, Germany
| | - Filip Kilibarda
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Bautzner Landstraße 400, 01328 Dresden, Germany
| | - Florian Günther
- Instituto de Física de São Carlos, Universidade de São Paulo, USP Av. Trabalhador saocarlense, 400, 13560-970, São Carlos, São Paulo, Brazil
| | - Jeffrey Kelling
- Department of Information Services and Computing, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Bautzner Landstraße 400, 01328 Dresden, Germany
- Institute of Physics, Technische Universität Chemnitz, 09107 Chemnitz, Germany
| | - Alexander Strobel
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Bautzner Landstraße 400, 01328 Dresden, Germany
| | - Peter Zahn
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Bautzner Landstraße 400, 01328 Dresden, Germany
| | - Guido Juckeland
- Department of Information Services and Computing, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Bautzner Landstraße 400, 01328 Dresden, Germany
| | - Kurt V Gothelf
- Department of Chemistry and Interdisciplinary Nanoscience Center, Centre for DNA Nanotechnology, iNANO, Gustav Wieds Vej 14, Aarhus C, 8000 Denmark
| | - Elke Scheer
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
| | - Sibylle Gemming
- Institute of Physics, Technische Universität Chemnitz, 09107 Chemnitz, Germany
| | - Artur Erbe
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Bautzner Landstraße 400, 01328 Dresden, Germany
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7
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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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8
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Bai X, Li P, Peng W, Chen N, Lin JL, Li Y. Ionogel-Electrode for the Study of Protein Tunnel Junctions under Physiologically Relevant Conditions. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023:e2300663. [PMID: 36965118 DOI: 10.1002/adma.202300663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 03/08/2023] [Indexed: 05/15/2023]
Abstract
The study of charge transport through proteins is essential for understanding complicated electrochemical processes in biological activities while the reasons for the coexistence of tunneling and hopping phenomena in protein junctions still remain unclear. In this work, a flexible and conductive ionogel electrode is synthesized and is used as a top contact to form highly reproducible protein junctions. The junctions of proteins, including human serum albumin, cytochrome C and hemoglobin, show temperature-independent electron tunneling characteristics when the junctions are in solid states while with a different mechanism of temperature-dependent electron hopping when junctions are hydrated under physiologically relevant conditions. It is demonstrated that the solvent reorganization energy plays an important role in the electron-hopping process and experimentally shown that it requires ≈100 meV for electron hopping through one heme group inside a hydrated protein molecule connected between two electrodes.
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Affiliation(s)
- Xiyue Bai
- Key Laboratory of Organic Optoelectronics and Molecular Engineering and Laboratory of Flexible Electronics Technology, Department of Chemistry, Tsinghua University, 100084, Beijing, China
| | - Pengfei Li
- Key Laboratory of Organic Optoelectronics and Molecular Engineering and Laboratory of Flexible Electronics Technology, Department of Chemistry, Tsinghua University, 100084, Beijing, China
| | - Wuxian Peng
- Key Laboratory of Organic Optoelectronics and Molecular Engineering and Laboratory of Flexible Electronics Technology, Department of Chemistry, Tsinghua University, 100084, Beijing, China
| | - Ningyue Chen
- Key Laboratory of Organic Optoelectronics and Molecular Engineering and Laboratory of Flexible Electronics Technology, Department of Chemistry, Tsinghua University, 100084, Beijing, China
| | - Jin-Liang Lin
- Key Laboratory of Organic Optoelectronics and Molecular Engineering and Laboratory of Flexible Electronics Technology, Department of Chemistry, Tsinghua University, 100084, Beijing, China
| | - Yuan Li
- Key Laboratory of Organic Optoelectronics and Molecular Engineering and Laboratory of Flexible Electronics Technology, Department of Chemistry, Tsinghua University, 100084, Beijing, China
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9
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Gupta R, Fereiro JA, Bayat A, Pritam A, Zharnikov M, Mondal PC. Nanoscale molecular rectifiers. Nat Rev Chem 2023; 7:106-122. [PMID: 37117915 DOI: 10.1038/s41570-022-00457-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/30/2022] [Indexed: 01/15/2023]
Abstract
The use of molecules bridged between two electrodes as a stable rectifier is an important goal in molecular electronics. Until recently, however, and despite extensive experimental and theoretical work, many aspects of our fundamental understanding and practical challenges have remained unresolved and prevented the realization of such devices. Recent advances in custom-designed molecular systems with rectification ratios exceeding 105 have now made these systems potentially competitive with existing silicon-based devices. Here, we provide an overview and critical analysis of recent progress in molecular rectification within single molecules, self-assembled monolayers, molecular multilayers, heterostructures, and metal-organic frameworks and coordination polymers. Examples of conceptually important and best-performing systems are discussed, alongside their rectification mechanisms. We present an outlook for the field, as well as prospects for the commercialization of molecular rectifiers.
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10
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Estimating the Number of Molecules in Molecular Junctions Merely Based on the Low Bias Tunneling Conductance at Variable Temperature. Int J Mol Sci 2022; 23:ijms232314985. [PMID: 36499309 PMCID: PMC9737784 DOI: 10.3390/ijms232314985] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 11/23/2022] [Accepted: 11/25/2022] [Indexed: 12/05/2022] Open
Abstract
Temperature (T) dependent conductance G=G(T) data measured in molecular junctions are routinely taken as evidence for a two-step hopping mechanism. The present paper emphasizes that this is not necessarily the case. A curve of lnG versus 1/T decreasing almost linearly (Arrhenius-like regime) and eventually switching to a nearly horizontal plateau (Sommerfeld regime), or possessing a slope gradually decreasing with increasing 1/T is fully compatible with a single-step tunneling mechanism. The results for the dependence of G on T presented include both analytical exact and accurate approximate formulas and numerical simulations. These theoretical results are general, also in the sense that they are not limited, e.g., to the (single molecule electromigrated (SET) or large area EGaIn) fabrication platforms, which are chosen for exemplification merely in view of the available experimental data needed for analysis. To be specific, we examine in detail transport measurements for molecular junctions based on ferrocene (Fc). As a particularly important finding, we show how the present analytic formulas for G=G(T) can be utilized to compute the ratio f=Aeff/An between the effective and nominal areas of large area Fc-based junctions with an EGaIn top electrode. Our estimate of f≈0.6×10-4 is comparable with previously reported values based on completely different methods for related large area molecular junctions.
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11
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Nguyen AT, Lee Y, Nguyen PQH, Dera P, Yoon SH, Lee W. Enhancing the electrical properties of graphite nanoflake through gamma-ray irradiation. Sci Rep 2022; 12:14824. [PMID: 36050363 PMCID: PMC9437066 DOI: 10.1038/s41598-022-19232-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 08/25/2022] [Indexed: 11/09/2022] Open
Abstract
Understanding changes in material properties through external stimuli is critical to validating the expected performance of materials as well as engineering material properties in a controlled manner. Here, we investigate a change in the c-axis electrical properties of graphite nanoflakes (GnFs) induced by gamma-ray irradiation, using conductive probe atomic force microscopy (CP-AFM). The fundamentals behind the change in their electrical properties are elucidated by analyzing the interlayer spacing, graphitization, and morphology. An increase in gamma-ray irradiation dose for GnFs leads to an exponential increase in the electrical conductance and a gradual decrease in the interlayer spacing, while accompanying indistinguishable changes in their morphology. Our experimental results suggest that the c-axis electrical conductance enhancement of GnFs with gamma-ray irradiation might be attributed to a reduction in interlayer spacing, though the created defects may also play a role. This study demonstrates that gamma-ray irradiation can be a promising route to tailor the electrical properties of GnFs.
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Affiliation(s)
- Anh Tuan Nguyen
- Department of Mechanical Engineering, University of Hawaii at Manoa, Honolulu, HI, 96822, USA
| | - Youlim Lee
- Bioinspired Engineering Laboratory, Department of Mechanical Engineering, Inha University, Incheon, 22212, Republic of Korea
| | - Phuong Quang Hoang Nguyen
- Hawaii Institute of Geophysics and Planetology, University of Hawaii at Manoa, Honolulu, HI, 96822, USA
| | - Przemyslaw Dera
- Hawaii Institute of Geophysics and Planetology, University of Hawaii at Manoa, Honolulu, HI, 96822, USA
| | - Sang-Hee Yoon
- Bioinspired Engineering Laboratory, Department of Mechanical Engineering, Inha University, Incheon, 22212, Republic of Korea.
| | - Woochul Lee
- Department of Mechanical Engineering, University of Hawaii at Manoa, Honolulu, HI, 96822, USA.
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12
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Behera RK, Mishra L, Panigrahi A, Sahoo PK, Sarangi MK. Tunable Conductance of MoS 2 and WS 2 Quantum Dots by Electron Transfer with Redox-Active Quinone. ACS APPLIED MATERIALS & INTERFACES 2022; 14:5750-5761. [PMID: 35049294 DOI: 10.1021/acsami.1c18092] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Due to their uniqueness in tunable photophysics, transition metal dichalcogenide (TMD) based quantum dots (QDs) have emerged as the next-generation quantum materials for technology-based semiconductor applications. This demands frontline research on the rational synthesis of the TMD QDs with controlled shape, size, nature of charge migration at the interface, and their easy integration in optoelectronic devices. In this article, with a controlled solution-processed synthesis of MoS2 and WS2 QDs, we demonstrate the disparity in their structural, optical, and electrical characteristics in bulk and confinement. With a series of steady-state and time-resolved spectroscopic measurements in different media, we explore the uncommon photophysics of MoS2 and WS2 QDs such as excitation-dependent photoluminescence and assess their excited state charge transfer kinetics with a redox-active biomolecule, menadione (MQ). In comparison to the homogeneous aqueous medium, photoinduced charge transfer between the QDs and MQ becomes more plausible in encapsulated cetyltrimethylammonium bromide (CTAB) micelles. Current sensing atomic force microscopy (CS-AFM) measurements at a single molecular level reveal that the facilitated charge transfer of QDs with MQ strongly correlates with an enhancement in their charge transport behavior. An increase in charge transport further depends on the density of states of the QDs directing a change in Schottky emission to Fowler-Nordheim (FN) type of tunneling across the metal-QD-metal junction. The selective response of the TMD QDs while in proximity to external molecules can be used to design advanced optoelectronic devices and applications involving rectifiers and tunnel diodes for future quantum technology.
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Affiliation(s)
- Ranjan Kumar Behera
- Department of Physics, Indian Institute of Technology Patna, Bihta, Kanpa Road, Patna, Bihar 801106, India
| | - Leepsa Mishra
- Department of Physics, Indian Institute of Technology Patna, Bihta, Kanpa Road, Patna, Bihar 801106, India
| | - Aradhana Panigrahi
- Department of Physics, Indian Institute of Technology Patna, Bihta, Kanpa Road, Patna, Bihar 801106, India
| | - Prasana Kumar Sahoo
- Materials Science Centre, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
| | - Manas Kumar Sarangi
- Department of Physics, Indian Institute of Technology Patna, Bihta, Kanpa Road, Patna, Bihar 801106, India
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13
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Akhtar A, Rashid U, Seth C, Kumar S, Broekmann P, Kaliginedi V. Modulating the charge transport in metal│molecule│metal junctions via electrochemical gating. Electrochim Acta 2021. [DOI: 10.1016/j.electacta.2021.138540] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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14
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Yuan S, Gao T, Cao W, Pan Z, Liu J, Shi J, Hong W. The Characterization of Electronic Noise in the Charge Transport through Single-Molecule Junctions. SMALL METHODS 2021; 5:e2001064. [PMID: 34927823 DOI: 10.1002/smtd.202001064] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 12/09/2020] [Indexed: 06/14/2023]
Abstract
With the goal of creating single-molecule devices and integrating them into circuits, the emergence of single-molecule electronics provides various techniques for the fabrication of single-molecule junctions and the investigation of charge transport through such junctions. Among the techniques for characterization of charge transport through molecular junctions, electronic noise characterization is an effective strategy with which issues from molecule-electrode interfaces, mechanisms of charge transport, and changes in junction configurations are studied. Electronic noise analysis in single-molecule junctions can be used to identify molecular conformations and even monitor reaction kinetics. This review summarizes the various types of electronic noise that have been characterized during single-molecule electrical detection, including the functions of random telegraph signal (RTS) noise, flicker noise, shot noise, and their corresponding applications, which provide some guidelines for the future application of these techniques to problems of charge transport through single-molecule junctions.
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Affiliation(s)
- Saisai Yuan
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering iChEM, Xiamen University, Xiamen, 361005, China
| | - Tengyang Gao
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering iChEM, Xiamen University, Xiamen, 361005, China
| | - Wenqiang Cao
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering iChEM, Xiamen University, Xiamen, 361005, China
| | - Zhichao Pan
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering iChEM, Xiamen University, Xiamen, 361005, China
| | - Junyang Liu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering iChEM, Xiamen University, Xiamen, 361005, China
| | - Jia Shi
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering iChEM, Xiamen University, Xiamen, 361005, China
| | - Wenjing Hong
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering iChEM, Xiamen University, Xiamen, 361005, China
- Beijing National Laboratory for Molecular Sciences, Beijing, 100190, China
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15
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Taskin MB, Ahmad T, Wistlich L, Meinel L, Schmitz M, Rossi A, Groll J. Bioactive Electrospun Fibers: Fabrication Strategies and a Critical Review of Surface-Sensitive Characterization and Quantification. Chem Rev 2021; 121:11194-11237. [DOI: 10.1021/acs.chemrev.0c00816] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Mehmet Berat Taskin
- Department of Functional Materials in Medicine and Dentistry and Bavarian Polymer Institute, University of Würzburg, 97070 Würzburg, Germany
| | - Taufiq Ahmad
- Department of Functional Materials in Medicine and Dentistry and Bavarian Polymer Institute, University of Würzburg, 97070 Würzburg, Germany
| | - Laura Wistlich
- Department of Functional Materials in Medicine and Dentistry and Bavarian Polymer Institute, University of Würzburg, 97070 Würzburg, Germany
| | - Lorenz Meinel
- Institute of Pharmacy and Food Chemistry and Helmholtz Institute for RNA Based Infection Research, 97074 Würzburg, Germany
| | - Michael Schmitz
- Department of Functional Materials in Medicine and Dentistry and Bavarian Polymer Institute, University of Würzburg, 97070 Würzburg, Germany
| | - Angela Rossi
- Department of Functional Materials in Medicine and Dentistry and Bavarian Polymer Institute, University of Würzburg, 97070 Würzburg, Germany
| | - Jürgen Groll
- Department of Functional Materials in Medicine and Dentistry and Bavarian Polymer Institute, University of Würzburg, 97070 Würzburg, Germany
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16
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Boucher DG, Kearney K, Ertekin E, Rose MJ. Tuning p-Si(111) Photovoltage via Molecule|Semiconductor Electronic Coupling. J Am Chem Soc 2021; 143:2567-2580. [PMID: 33534568 DOI: 10.1021/jacs.0c12075] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Photoelectrochemical (PEC) device efficiency depends heavily on the energetics and band alignment of the semiconductor|overlayer junction. Exerting energetic control over these junctions via molecular functionalization is an extremely attractive strategy. Herein we report a study of the structure-function relationship between chemically functionalized pSi(111) and the resulting solar fuels performance. Specifically, we highlight the interplay of chemical structure and electronic coupling between the attached molecule and the underlying semiconductor. Covalent attachment of aryl surface modifiers (phenyl, Ph; nitrophenyl, PhNO2; anthracene, Anth; and nitroanthracene, AnthNO2) resulted in high-fidelity surfaces with low defect densities (S < 50 cm/s). Electrochemical characterization of these surfaces in contact with methyl viologen resulted in systematically shifted band edges (up to 0.99 V barrier height) and correspondingly high photoelectrochemical performance (Voc up to 0.43 V vs MV2+) consistent with the introduction of a positive interfacial dipole. We extend this functionalization to HER conditions and demonstrate systematic tuning of the HER Voc using pSi(111)-R|TiO2|Pt architecture. Correlation of the shifts in barrier height with the photovoltage provides evidence for nonideality despite low surface recombination. Critically, DFT calculations of the electronic structure of the organic-functionalized interfaces show that the molecule-based electronic states effectively hybridized with the silicon band edges. A comparison of these interfacial states with their isolated molecular analogues further confirms electronic coupling between the attached molecule and the underlying semiconductor, providing an induced density of interfacial states (IDIS) which decreases the potential drop across the semiconductor. These results demonstrate the delicate interplay between interfacial chemical structure, interfacial dipole, and electronic structure.
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Affiliation(s)
- Dylan G Boucher
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Kara Kearney
- Department of Mechanical Science and Engineering, University of Illinois, Urbana, Illinois 61801, United States
| | - Elif Ertekin
- Department of Mechanical Science and Engineering, University of Illinois, Urbana, Illinois 61801, United States.,Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, Fukuoka, Japan
| | - Michael J Rose
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
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17
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Park J, Belding L, Yuan L, Mousavi MPS, Root SE, Yoon HJ, Whitesides GM. Rectification in Molecular Tunneling Junctions Based on Alkanethiolates with Bipyridine-Metal Complexes. J Am Chem Soc 2021; 143:2156-2163. [PMID: 33480255 DOI: 10.1021/jacs.0c12641] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
This paper addresses the mechanism for rectification in molecular tunneling junctions based on alkanethiolates terminated by a bipyridine group complexed with a metal ion, that is, having the structure AuTS-S(CH2)11BIPY-MCl2 (where M = Co or Cu) with a eutectic indium-gallium alloy top contact (EGaIn, 75.5% Ga 24.5% In). Here, AuTS-S(CH2)11BIPY is a self-assembled monolayer (SAM) of an alkanethiolate with 4-methyl-2,2'-bipyridine (BIPY) head groups, on template-stripped gold (AuTS). When the SAM is exposed to cobalt(II) chloride, SAMs of the form AuTS-S(CH2)11BIPY-CoCl2 rectify current with a rectification ratio of r+ = 82.0 at ±1.0 V. The rectification, however, disappears (r+ = 1.0) when the SAM is exposed to copper(II) chloride instead of cobalt. We draw the following conclusions from our experimental results: (i) AuTS-S(CH2)11BIPY-CoCl2 junctions rectify current because only at positive bias (+1.0 V) is there an accessible molecular orbital (the LUMO) on the BIPY-CoCl2 moiety, while at negative bias (-1.0 V), neither the energy level of the HOMO or the LUMO lies between the Fermi levels of the electrodes. (ii) AuTS-S(CH2)11BIPY-CuCl2 junctions do not rectify current because there is an accessible molecular orbital on the BIPY-CuCl2 moiety at both negative and positive bias (the HOMO is accessible at negative bias, and the LUMO is accessible at positive bias). The difference in accessibility of the HOMO levels at -1.0 V causes charge transfer-at negative bias-to take place via Fowler-Nordheim tunneling in BIPY-CoCl2 junctions, and via direct tunneling in BIPY-CuCl2 junctions. This difference in tunneling mechanism at negative bias is the origin of the difference in rectification ratio between BIPY-CoCl2 and BIPY-CuCl2 junctions.
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Affiliation(s)
- Junwoo Park
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Lee Belding
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Li Yuan
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Maral P S Mousavi
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Samuel E Root
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Hyo Jae Yoon
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States.,Department of Chemistry, Korea University, Seoul 02841, Korea
| | - George M Whitesides
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
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18
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Sowa JK, Marcus RA. On the theory of charge transport and entropic effects in solvated molecular junctions. J Chem Phys 2021; 154:034110. [DOI: 10.1063/5.0034782] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Jakub K. Sowa
- Department of Materials, University of Oxford, OX1 3PH Oxford, United Kingdom
| | - Rudolph A. Marcus
- Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, USA
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19
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Delmas V, Diez-Cabanes V, van Dyck C, Scheer E, Costuas K, Cornil J. On the reliability of acquiring molecular junction parameters by Lorentzian fitting of I/ V curves. Phys Chem Chem Phys 2020; 22:26702-26706. [PMID: 33216107 DOI: 10.1039/d0cp05372d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Fitting the I/V curves of molecular junctions by simple analytical models is often done to extract relevant molecular parameters such as energy level alignment or interfacial electronic coupling to build up useful property-relationships. However, such models can suffer from severe limitations and hence provide unreliable molecular parameters. This is illustrated here by extracting key molecular parameters by fitting computed voltage-dependent transmission spectra and by comparing them to the values obtained by fitting the calculated I/V curves with a typical Lorentzian model used in the literature. Doing so, we observe a large discrepancy between the two sets of values which warns us about the risks of using simple fitting expressions. Interestingly, we demonstrate that the quality of the fit can be improved by imposing the low bias conductance and Seebeck coefficient of the junction to be recovered in the fitting procedure.
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Affiliation(s)
- Vincent Delmas
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, F-35000 Rennes, France.
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20
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Xu B, Saygin V, Brown KA, Andersson SB. High-resolution measurement of atomic force microscope cantilever resonance frequency. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:123705. [PMID: 33379947 DOI: 10.1063/5.0026069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 12/07/2020] [Indexed: 06/12/2023]
Abstract
The atomic force microscope (AFM) is widely used in a wide range of applications due to its high scanning resolution and diverse scanning modes. In many applications, there is a need for accurate and precise measurement of the vibrational resonance frequency of a cantilever. These frequency shifts can be related to changes in mass of the cantilever arising from, e.g., loss of fluid due to a nanolithography operation. A common method of measuring resonance frequency examines the power spectral density of the free random motion of the cantilever, commonly known as a thermal. While the thermal is capable of reasonable measurement resolution and speed, some applications are sensitive to changes in the resonance frequency of the cantilever, which are small, rapid, or both, and the performance of the thermal does not offer sufficient resolution in frequency or in time. In this work, we describe a method based on a narrow-range frequency sweep to measure the resonance frequency of a vibrational mode of an AFM cantilever and demonstrate it by monitoring the evaporation of glycerol from a cantilever. It can be seamlessly integrated into many commercial AFMs without additional hardware modifications and adapts to cantilevers with a wide range of resonance frequencies. Furthermore, this method can rapidly detect small changes in resonance frequency (with our experiments showing a resolution of ∼0.1 Hz for cantilever resonances ranging from 70 kHz to 300 kHz) at a rate far faster than with a thermal. These attributes are particularly beneficial for techniques such as dip-pen nanolithography.
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Affiliation(s)
- Bowen Xu
- Department of Mechanical Engineering, Boston University, Boston, Massachusetts 02215, USA
| | - Verda Saygin
- Department of Mechanical Engineering, Boston University, Boston, Massachusetts 02215, USA
| | - Keith A Brown
- Department of Mechanical Engineering, Boston University, Boston, Massachusetts 02215, USA
| | - Sean B Andersson
- Department of Mechanical Engineering, Boston University, Boston, Massachusetts 02215, USA
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21
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Mundinamani S. Large Area, Multilayer Graphene Films as a Flexible Electronic Material. ACS OMEGA 2020; 5:17479-17485. [PMID: 32715233 PMCID: PMC7377635 DOI: 10.1021/acsomega.0c01982] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 06/26/2020] [Indexed: 06/11/2023]
Abstract
Chemically reduced graphene oxide possesses unique properties and leads to a secure processing method for many applications. The electrical and optical properties of graphene oxide are strongly dependent on the chemical and atomic structure. In the present work, the reduction of synthesized multilayer graphene oxide sheets by both chemical and thermal methods to use them as a substrate in the field of molecular electronic device fabrication is reported. 1-Dodecanethiol molecules are used to covalently bond on the surface atoms of reduced graphene oxide to constitute molecular electronic devices. The metal-organic molecules-reduced graphene oxide-metal junctions show a significant reduction in current levels and weak diode behavior. The observations confirm the tunneling as the conduction mechanism. The sheets are low cost, highly flexible, and can be used as a substrate to build the molecular electronic junctions.
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22
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Phase imaging of transition from classical to quantum plasmonic couplings between a metal nanoparticle and a metal surface. Proc Natl Acad Sci U S A 2020; 117:17564-17570. [PMID: 32665434 DOI: 10.1073/pnas.2006443117] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
When a metal nanoparticle is brought near to a metal surface within electron tunneling distance (∼1 nm), classical electromagnetic coupling between the nanoparticle and the metal is expected to transition to quantum coupling. We show that this transition can be observed as a drastic phase change in the surface plasmon resonance (SPR) images of the gold nanoparticles. We study the transition by controlling the distance between the nanoparticles and electrode surface, modeling the impact of the transition on the SPR image in terms of a phase shift and demonstrating detection of microRNA based on the transition from classical to quantum coupling. The work shows that the quantum coupling can be directly visualized in SPR, and the extremely sensitive dependence of the transition on distance leads to a biosensing principle with SPR.
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23
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Han B, Li Y, Ji X, Song X, Ding S, Li B, Khalid H, Zhang Y, Xu X, Tian L, Dong H, Yu X, Hu W. Systematic Modulation of Charge Transport in Molecular Devices through Facile Control of Molecule-Electrode Coupling Using a Double Self-Assembled Monolayer Nanowire Junction. J Am Chem Soc 2020; 142:9708-9717. [PMID: 32362123 DOI: 10.1021/jacs.0c02215] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
We report a novel solid-state molecular device structure based on double self-assembled monolayers (D-SAM) incorporated into the suspended nanowire architecture to form a "Au|SAM-1||SAM-2|Au" junction. Using commercially available thiol molecules that are devoid of synthetic difficulty, we constructed a "Au|S-(CH2)6-ferrocene||SAM-2|Au" junction with various lengths and chemical structures of SAM-2 to tune the coupling between the ferrocene conductive molecular orbital and electrode of the junction. Combining low noise and a wide temperature range measurement, we demonstrated systematically modulated conduction depending on the length and chemical nature of SAM-2. Meanwhile, the transport mechanism transition from tunneling to hopping and the intermediate state accompanied by the current fluctuation due to the coexistence of the hopping and tunneling transport channels were observed. Considering the versatility of this solid-state D-SAM in modulating the electrode-molecule interface and electroactive groups, this strategy thus provides a novel facile strategy for tailorable nanoscale charge transport studies and functional molecular devices.
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Affiliation(s)
- Bin Han
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science, Tianjin University & Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, China
| | - Yao Li
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science, Tianjin University & Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, China
| | - Xuan Ji
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science, Tianjin University & Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, China
| | - Xianneng Song
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science, Tianjin University & Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, China
| | - Shuaishuai Ding
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Baili Li
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science, Tianjin University & Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, China
| | - Hira Khalid
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science, Tianjin University & Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, China
| | - Yaogang Zhang
- School of Science, Yanshan University, Qinhuangdao 066004, China
| | - Xiaona Xu
- School of Science, Yanshan University, Qinhuangdao 066004, China
| | - Lixian Tian
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science, Tianjin University & Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, China
| | - Huanli Dong
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Xi Yu
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science, Tianjin University & Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, China
| | - Wenping Hu
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science, Tianjin University & Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, China
- Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Binhai New City, Fuzhou 350207, China
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24
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Mukhopadhyay S, Karuppannan SK, Guo C, Fereiro JA, Bergren A, Mukundan V, Qiu X, Castañeda Ocampo OE, Chen X, Chiechi RC, McCreery R, Pecht I, Sheves M, Pasula RR, Lim S, Nijhuis CA, Vilan A, Cahen D. Solid-State Protein Junctions: Cross- Laboratory Study Shows Preservation of Mechanism at Varying Electronic Coupling. iScience 2020; 23:101099. [PMID: 32438319 PMCID: PMC7235645 DOI: 10.1016/j.isci.2020.101099] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 03/01/2020] [Accepted: 04/20/2020] [Indexed: 12/14/2022] Open
Abstract
Successful integration of proteins in solid-state electronics requires contacting them in a non-invasive fashion, with a solid conducting surface for immobilization as one such contact. The contacts can affect and even dominate the measured electronic transport. Often substrates, substrate treatments, protein immobilization, and device geometries differ between laboratories. Thus the question arises how far results from different laboratories and platforms are comparable and how to distinguish genuine protein electronic transport properties from platform-induced ones. We report a systematic comparison of electronic transport measurements between different laboratories, using all commonly used large-area schemes to contact a set of three proteins of largely different types. Altogether we study eight different combinations of molecular junction configurations, designed so that Ageoof junctions varies from 105 to 10-3 μm2. Although for the same protein, measured with similar device geometry, results compare reasonably well, there are significant differences in current densities (an intensive variable) between different device geometries. Likely, these originate in the critical contact-protein coupling (∼contact resistance), in addition to the actual number of proteins involved, because the effective junction contact area depends on the nanometric roughness of the electrodes and at times, even the proteins may increase this roughness. On the positive side, our results show that understanding what controls the coupling can make the coupling a design knob. In terms of extensive variables, such as temperature, our comparison unanimously shows the transport to be independent of temperature for all studied configurations and proteins. Our study places coupling and lack of temperature activation as key aspects to be considered in both modeling and practice of protein electronic transport experiments.
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Affiliation(s)
- Sabyasachi Mukhopadhyay
- Weizmann Institute of Science, Rehovot 76100, Israel
- Department of Physics, SRM University – AP, Amaravati, Andhra Pradesh 522502, India
| | - Senthil Kumar Karuppannan
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
| | - Cunlan Guo
- Weizmann Institute of Science, Rehovot 76100, Israel
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China
| | | | - Adam Bergren
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Dr., Edmonton AB T6G 2G2, Canada
| | - Vineetha Mukundan
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Dr., Edmonton AB T6G 2G2, Canada
| | - Xinkai Qiu
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, the Netherlands
| | - Olga E. Castañeda Ocampo
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, the Netherlands
| | - Xiaoping Chen
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
| | - Ryan C. Chiechi
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, the Netherlands
| | - Richard McCreery
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Dr., Edmonton AB T6G 2G2, Canada
| | - Israel Pecht
- Weizmann Institute of Science, Rehovot 76100, Israel
| | | | - Rupali Reddy Pasula
- School of Chemical and Biomedical Engineering, Nanyang Technological University, 70 Nanyang Drive, Singapore 637457, Singapore
| | - Sierin Lim
- School of Chemical and Biomedical Engineering, Nanyang Technological University, 70 Nanyang Drive, Singapore 637457, Singapore
| | - Christian A. Nijhuis
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
- Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, Singapore 117546, Singapore
| | - Ayelet Vilan
- Weizmann Institute of Science, Rehovot 76100, Israel
| | - David Cahen
- Weizmann Institute of Science, Rehovot 76100, Israel
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25
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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.
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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
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Li B, Tian L, He X, Ji X, Khalid H, Yue C, Liu Q, Yu X, Lei S, Hu W. Tunable oligo-histidine self-assembled monolayer junction and charge transport by a pH modulated assembly. Phys Chem Chem Phys 2019; 21:26058-26065. [PMID: 31746863 DOI: 10.1039/c9cp04695j] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Histidine works as an important mediator in the charge transport process through proteins via its conjugate side group. It can also stabilize a peptide's secondary structure through hydrogen bonding of the imidazole group. In this study, the conformation of the self-assembled monolayer (SAM) and the charge transport of the tailor-made oligopeptide hepta-histidine derivative (7-His) were modulated through the pH control of the assembly environment. Histidine is found to be an efficient tunneling mediator in monolayer junctions with an attenuation factor of β = ∼0.5 Å-1. Successful theoretical model fitting indicates a linear increase in the number of tunneling sites as the 7-His SAM thickness increases, following the deprotonation of histidine. Combined with the ultraviolet photoelectron spectroscopy (UPS) measurements, a modulable charge transport pathway through 7-His with imidazole groups of histidine as tunneling foot stones is revealed. Histidine therefore possesses a large potential for modulable functional (bio)electronic devices.
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Affiliation(s)
- Baili Li
- Department of Chemistry, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, School of Science, Tianjin University and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, 300072, China.
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Zheng H, Jiang F, He R, Yang Y, Shi J, Hong W. Charge Transport through Peptides in Single‐Molecule Electrical Measurements. CHINESE J CHEM 2019. [DOI: 10.1002/cjoc.201900245] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Haining Zheng
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, iChEM, Xiamen University Xiamen Fujian 361005 China
| | - Feng Jiang
- Joint Research Center for Peptide Drug R&D with Space Peptides, College of Chemistry and Chemical Engineering, Xiamen University Xiamen Fujian 361005 China
| | - Runze He
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, iChEM, Xiamen University Xiamen Fujian 361005 China
- Joint Research Center for Peptide Drug R&D with Space Peptides, College of Chemistry and Chemical Engineering, Xiamen University Xiamen Fujian 361005 China
| | - Yang Yang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, iChEM, Xiamen University Xiamen Fujian 361005 China
| | - Jia Shi
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, iChEM, Xiamen University Xiamen Fujian 361005 China
| | - Wenjing Hong
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, iChEM, Xiamen University Xiamen Fujian 361005 China
- Joint Research Center for Peptide Drug R&D with Space Peptides, College of Chemistry and Chemical Engineering, Xiamen University Xiamen Fujian 361005 China
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28
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Vuillaume D. Molecular Electronics: From Single‐Molecule to Large‐Area Devices. Chempluschem 2019; 84:1215-1221. [DOI: 10.1002/cplu.201900171] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 05/08/2019] [Indexed: 11/09/2022]
Affiliation(s)
- Dominique Vuillaume
- Institute for Electronics Microelectronics and Nanotechnology CNRSUniversité de Lille Avenue Poincaré CS60069, 59652 cedex Villeneuve d'Ascq France
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Lamport ZA, Broadnax AD, Scharmann B, Bradford RW, DelaCourt A, Meyer N, Li H, Geyer SM, Thonhauser T, Welker ME, Jurchescu OD. Molecular Rectifiers on Silicon: High Performance by Enhancing Top-Electrode/Molecule Coupling. ACS APPLIED MATERIALS & INTERFACES 2019; 11:18564-18570. [PMID: 31050879 DOI: 10.1021/acsami.9b02315] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
One of the simplest molecular-scale electronic devices is the molecular rectifier. In spite of considerable efforts aimed at understanding structure-property relationships in these systems, devices with predictable and stable electronic properties are yet to be developed. Here, we demonstrate highly efficient current rectification in a new class of compounds that form self-assembled monolayers on silicon. We achieve this by exploiting the coupling of the molecules with the top electrode which, in turn, controls the position of the relevant molecular orbitals. The molecules consist of a silane anchoring group and a nitrogen-substituted benzene ring, separated by a propyl group and imine linkage, and result from a simple, robust, and high-yield synthetic procedure. We find that when incorporated in molecular diodes, these compounds can rectify current by as much as 3 orders of magnitude, depending on their structure, with a maximum rectification ratio of 2635 being obtained in ( E)-1-(4-cyanophenyl)- N-(3-(triethoxysilyl) propyl)methanimine (average Ravg = 1683 ± 458, at an applied voltage of 2 V). This performance is on par with that of the best molecular rectifiers obtained on metallic electrodes, but it has the advantage of lower cost and more efficient integration with current silicon technologies. The development of molecular rectifiers on silicon may yield hybrid systems that can expand the use of silicon toward novel functionalities governed by the molecular species grafted onto its surface.
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Kumar S, Merelli M, Danowski W, Rudolf P, Feringa BL, Chiechi RC. Chemical Locking in Molecular Tunneling Junctions Enables Nonvolatile Memory with Large On-Off Ratios. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1807831. [PMID: 30721551 DOI: 10.1002/adma.201807831] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 01/16/2019] [Indexed: 05/24/2023]
Abstract
This paper describes the reversible chemical locking of sypiropyran switches bound to metallic surfaces to enable the encoding of nonvolatile information. Data are encoded spatially by selectively locking the spiropyran moieties in their merocyanine form using a combination of exposure to acid and UV light. Without exposure to acid, the merocyanine form spontaneously converts back to the spiropyran form. Bits are resolved by defining the regions of the monolayer that are exposed to acid, using a "soft punchcard" fabricated from a silicone elastomer. Information is read by measuring the tunneling charge-transport through the monolayer using eutectic Ga-In top-contacts. The merocyanine form is more than three orders of magnitude more conductive than the spiropyran form, allowing the differentiation of bits. Photoelectron spectroscopy shows that the monolayers are undamaged by exposure to light, acid, base, and applied bias, enabling proof-of-concept devices in which an 8-bit ASCII encoded six-character string is written, erased, and rewritten.
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Affiliation(s)
- Sumit Kumar
- Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Michele Merelli
- Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Wojciech Danowski
- Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Petra Rudolf
- Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Ben L Feringa
- Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Ryan C Chiechi
- Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
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31
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Mejía L, Franco I. Force-conductance spectroscopy of a single-molecule reaction. Chem Sci 2019; 10:3249-3256. [PMID: 30996909 PMCID: PMC6429593 DOI: 10.1039/c8sc04830d] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 01/24/2019] [Indexed: 01/23/2023] Open
Abstract
We demonstrate how simultaneous measurements of conductance and force can be used to monitor the step-by-step progress of a mechanically-activated cis-to-trans isomerization single-molecule reaction, including events that cannot be distinguished using force or conductance alone. To do so, we simulated the force-conductance profile of cyclopropane oligomers connected to graphene nanoribbon electrodes that undergo a cis-to-trans isomerization during mechanical elongation. This was done using a combination of classical molecular dynamics simulation of the pulling using a reactive force field, and Landauer transport computations of the conductance with nonequilibrium Green's function methods. The isomerization events can be distinguished in both force and conductance profiles. However, the conductance profile during the mechanical elongation distinguishes between reaction intermediates that cannot be resolved using force. In turn, the force signals non-reactive deformations in the molecular backbone which are not visible in the conductance profile. These observations are shown to be robust to the choice of electrode and Hamiltonian model. The computations exemplify the potential of the integration of covalent mechanochemistry with molecular conductance to investigate chemical reactivity at the single-entity limit.
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Affiliation(s)
- Leopoldo Mejía
- Department of Chemistry , University of Rochester , Rochester , New York 14627-0216 , USA .
| | - Ignacio Franco
- Department of Chemistry , University of Rochester , Rochester , New York 14627-0216 , USA .
- Department of Physics , University of Rochester , Rochester , New York 14627-0216 , USA
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Gusain A, Faria RM, Miranda PB. Polymer Solar Cells-Interfacial Processes Related to Performance Issues. Front Chem 2019; 7:61. [PMID: 30809519 PMCID: PMC6379278 DOI: 10.3389/fchem.2019.00061] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 01/22/2019] [Indexed: 12/03/2022] Open
Abstract
Harnessing solar energy with solar cells based on organic materials (in particular polymeric solar cells) is an attractive alternative to silicon-based solar cells due to the advantages of lower weight, flexibility, lower manufacturing costs, easier integration with other products, low environmental impact during manufacturing and operations and short energy payback times. However, even with the latest efficiencies reported up to 17%, the reproducibility of these efficiencies is not up to par, with a significant variation in the efficiencies reported across the literature. Since these devices are based on ultrathin multilayer organic films, interfaces play a major role in their operation and performance. This review gives a concise account of the major interfacial issues that are responsible for influencing the device performance, with emphasis on their physical mechanisms. After an introduction to the basic principles of polymeric solar cells, it briefly discusses charge generation and recombination occurring at the donor-acceptor bulk heterojunction interface. It then discusses interfacial morphology for the active layer and how it affects the performance and stability of these devices. Next, the formation of injection and extraction barriers and their role in the device performance is discussed. Finally, it addresses the most common approaches to change these barriers for improving the solar cell efficiency, including the use of interface dipoles. These issues are interrelated to each other and give a clear and concise understanding of the problem of the underperformance due to interfacial phenomena occurring within the device. This review not only discusses some of the implemented approaches that have been adopted in order to address these problems, but also highlights interfacial issues that are yet to be fully understood in organic solar cells.
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Affiliation(s)
- Abhay Gusain
- Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, Brazil
| | - Roberto M Faria
- Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, Brazil
| | - Paulo B Miranda
- Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, Brazil
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Dalla Francesca K, Lenfant S, Laurans M, Volatron F, Izzet G, Humblot V, Methivier C, Guerin D, Proust A, Vuillaume D. Charge transport through redox active [H 7P 8W 48O 184] 33- polyoxometalates self-assembled onto gold surfaces and gold nanodots. NANOSCALE 2019; 11:1863-1878. [PMID: 30637426 DOI: 10.1039/c8nr09377f] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Polyoxometalates (POMs) are redox-active molecular oxides, which attract growing interest for their integration into nano-devices, such as high-density data storage non-volatile memories. In this work, we investigated the electrostatic deposition of the negatively charged [H7P8W48O184]33- POM onto positively charged 8-amino-1-octanethiol self-assembled monolayers (SAMs) preformed onto gold substrates or onto an array of gold nanodots. The ring-shaped [H7P8W48O184]33- POM was selected as an example of large POMs with high charge storage capacity. To avoid the formation of POM aggregates onto the substrates, which would introduce variability in the local electrical properties, special attention has to be paid to the preformed SAM seeding layer, which should itself be deprived of aggregates. Where necessary, rinsing steps were found to be crucial to eliminate these aggregates and to provide uniformly covered substrates for subsequent POM deposition and electrical characterizations. This especially holds for commercially available gold/glass substrates while these rinsing steps were not essential in the case of template stripped gold of very low roughness. Charge transport through the related molecular junctions and nanodot molecule junctions (NMJs) has been probed by conducting-AFM. We analyzed the current-voltage curves with different models: electron tunneling though the SAMs (Simmons model), transition voltage spectroscopy (TVS) method or molecular single energy level mediated transport (Landauer equation) and we discussed the energetics of the molecular junctions. We concluded to an energy level alignment of the alkyl spacer and POM lowest occupied molecular orbitals (LUMOs), probably due to dipolar effects.
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Affiliation(s)
- K Dalla Francesca
- Sorbonne Université, CNRS, Institut Parisien de Chimie Moléculaire, IPCM, 4 Place Jussieu, F-75005 Paris, France.
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34
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Tsuji Y, Yoshizawa K. Effects of electron-phonon coupling on quantum interference in polyenes. J Chem Phys 2018; 149:134115. [DOI: 10.1063/1.5048955] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Yuta Tsuji
- Institute for Materials Chemistry and Engineering and IRCCS, Kyushu University, Nishi-ku, Fukuoka 819-0395, Japan
| | - Kazunari Yoshizawa
- Institute for Materials Chemistry and Engineering and IRCCS, Kyushu University, Nishi-ku, Fukuoka 819-0395, Japan
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Xiao B, Liang F, Liu S, Im J, Li Y, Liu J, Zhang B, Zhou J, He J, Chang S. Cucurbituril mediated single molecule detection and identification via recognition tunneling. NANOTECHNOLOGY 2018; 29:365501. [PMID: 29882746 DOI: 10.1088/1361-6528/aacb63] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Recognition tunneling (RT) is an emerging technique for investigating single molecules in a tunnel junction. We have previously demonstrated its capability of single molecule detection and identification, as well as probing the dynamics of intermolecular bonding at the single molecule level. Here by introducing cucurbituril as a new class of recognition molecule, we demonstrate a powerful platform for electronically investigating the host-guest chemistry at single molecule level. In this report, we first investigated the single molecule electrical properties of cucurbituril in a tunnel junction. Then we studied two model guest molecules, aminoferrocene and amantadine, which were encapsulated by cucurbituril. Small differences in conductance and lifetime can be recognized between the host-guest complexes with the inclusion of different guest molecules. By using a machine learning algorithm to classify the RT signals in a hyper dimensional space, the accuracy of guest molecule recognition can be significantly improved, suggesting the possibility of using cucurbituril molecule for single molecule identification. This work enables a new class of recognition molecule for RT technique and opens the door for detecting a vast variety of small molecules by electrical measurements.
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Affiliation(s)
- Bohuai Xiao
- The State Key laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, People's Republic of China
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Moneo A, González-Orive A, Bock S, Fenero M, Herrer IL, Milan DC, Lorenzoni M, Nichols RJ, Cea P, Perez-Murano F, Low PJ, Martin S. Towards molecular electronic devices based on 'all-carbon' wires. NANOSCALE 2018; 10:14128-14138. [PMID: 29999063 DOI: 10.1039/c8nr02347f] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Nascent molecular electronic devices based on linear 'all-carbon' wires attached to gold electrodes through robust and reliable C-Au contacts are prepared via efficient in situ sequential cleavage of trimethylsilyl end groups from an oligoyne, Me3Si-(C[triple bond, length as m-dash]C)4-SiMe3 (1). In the first stage of the fabrication process, removal of one trimethylsilyl (TMS) group in the presence of a gold substrate, which ultimately serves as the bottom electrode, using a stoichiometric fluoride-driven process gives a highly-ordered monolayer, Au|C[triple bond, length as m-dash]CC[triple bond, length as m-dash]CC[triple bond, length as m-dash]CC[triple bond, length as m-dash]CSiMe3 (Au|C8SiMe3). In the second stage, treatment of Au|C8SiMe3 with excess fluoride results in removal of the remaining TMS protecting group to give a modified monolayer Au|C[triple bond, length as m-dash]CC[triple bond, length as m-dash]CC[triple bond, length as m-dash]CC[triple bond, length as m-dash]CH (Au|C8H). The reactive terminal C[triple bond, length as m-dash]C-H moiety in Au|C8H can be modified by 'click' reactions with (azidomethyl)ferrocene (N3CH2Fc) to introduce a redox probe, to give Au|C6C2N3HCH2Fc. Alternatively, incubation of the modified gold substrate supported monolayer Au|C8H in a solution of gold nanoparticles (GNPs), results in covalent attachment of GNPs on top of the film via a second alkynyl carbon-Au σ-bond, to give structures Au|C8|GNP in which the monolayer of linear, 'all-carbon' C8 chains is sandwiched between two macroscopic gold contacts. The covalent carbon-surface bond as well as the covalent attachment of the metal particles to the monolayer by cleavage of the alkyne C-H bond is confirmed by surface-enhanced Raman scattering (SERS). The integrity of the carbon chain in both Au|C6C2N3HCH2Fc systems and after formation of the gold top-contact electrode in Au|C8|GNP is demonstrated through electrochemical methods. The electrical properties of these nascent metal-monolayer-metal devices Au|C8|GNP featuring 'all-carbon' molecular wires were characterised by sigmoidal I-V curves, indicative of well-behaved junctions free of short circuits.
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Affiliation(s)
- Andrea Moneo
- Departamento de Química Física, Facultad de Ciencias, Universidad de Zaragoza, 50009, Spain.
| | - Alejandro González-Orive
- Departamento de Química Física, Facultad de Ciencias, Universidad de Zaragoza, 50009, Spain. and Instituto de Nanociencia de Aragón (INA) and Laboratorio de Microscopías Avanzadas (LMA), edificio i+d Campus Rio Ebro, Universidad de Zaragoza, C/Mariano Esquillor, s/n, 50018 Zaragoza, Spain
| | - Sören Bock
- School of Molecular Sciences, University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Marta Fenero
- Departamento de Química Física, Facultad de Ciencias, Universidad de Zaragoza, 50009, Spain. and Instituto de Nanociencia de Aragón (INA) and Laboratorio de Microscopías Avanzadas (LMA), edificio i+d Campus Rio Ebro, Universidad de Zaragoza, C/Mariano Esquillor, s/n, 50018 Zaragoza, Spain
| | - I Lucía Herrer
- Departamento de Química Física, Facultad de Ciencias, Universidad de Zaragoza, 50009, Spain. and Instituto de Nanociencia de Aragón (INA) and Laboratorio de Microscopías Avanzadas (LMA), edificio i+d Campus Rio Ebro, Universidad de Zaragoza, C/Mariano Esquillor, s/n, 50018 Zaragoza, Spain
| | - David C Milan
- Department of Chemistry, University of Liverpool, Liverpool, L69 7ZD, UK
| | - Matteo Lorenzoni
- Instituto de Microelectrónica de Barcelona (IMB-CNM, CSIC), Campus UAB, 08193 Bellaterra, Spain
| | - Richard J Nichols
- Department of Chemistry, University of Liverpool, Liverpool, L69 7ZD, UK
| | - Pilar Cea
- Departamento de Química Física, Facultad de Ciencias, Universidad de Zaragoza, 50009, Spain. and Instituto de Nanociencia de Aragón (INA) and Laboratorio de Microscopías Avanzadas (LMA), edificio i+d Campus Rio Ebro, Universidad de Zaragoza, C/Mariano Esquillor, s/n, 50018 Zaragoza, Spain
| | - Francesc Perez-Murano
- Instituto de Microelectrónica de Barcelona (IMB-CNM, CSIC), Campus UAB, 08193 Bellaterra, Spain
| | - Paul J Low
- School of Molecular Sciences, University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Santiago Martin
- Departamento de Química Física, Facultad de Ciencias, Universidad de Zaragoza, 50009, Spain. and Instituto de Ciencias de Materiales de Aragón (ICMA), Universidad de Zaragoza-CSIC, 50009 Zaragoza, Spain
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Umemura K, Sato S. Scanning Techniques for Nanobioconjugates of Carbon Nanotubes. SCANNING 2018; 2018:6254692. [PMID: 30008981 PMCID: PMC6020491 DOI: 10.1155/2018/6254692] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 04/29/2018] [Indexed: 05/17/2023]
Abstract
Nanobioconjugates using carbon nanotubes (CNTs) are attractive and promising hybrid materials. Various biological applications using the CNT nanobioconjugates, for example, drug delivery systems and nanobiosensors, have been proposed by many authors. Scanning techniques such as scanning electron microscopy (SEM) and scanning probe microscopy (SPM) have advantages to characterize the CNT nanobioconjugates under various conditions, for example, isolated conjugates, conjugates in thin films, and conjugates in living cells. In this review article, almost 300 papers are categorized based on types of CNT applications, and various scanning data are introduced to illuminate merits of scanning techniques.
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Affiliation(s)
- Kazuo Umemura
- Department of Physics, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku, Tokyo 1628601, Japan
| | - Shizuma Sato
- Department of Physics, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku, Tokyo 1628601, Japan
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Effect of Substrate Support on Dynamic Graphene/Metal Electrical Contacts. MICROMACHINES 2018; 9:mi9040169. [PMID: 30424102 PMCID: PMC6187266 DOI: 10.3390/mi9040169] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 04/05/2018] [Accepted: 04/06/2018] [Indexed: 11/17/2022]
Abstract
Recent advances in graphene and other two-dimensional (2D) material synthesis and characterization have led to their use in emerging technologies, including flexible electronics. However, a major challenge is electrical contact stability, especially under mechanical straining or dynamic loading, which can be important for 2D material use in microelectromechanical systems. In this letter, we investigate the stability of dynamic electrical contacts at a graphene/metal interface using atomic force microscopy (AFM), under static conditions with variable normal loads and under sliding conditions with variable speeds. Our results demonstrate that contact resistance depends on the nature of the graphene support, specifically whether the graphene is free-standing or supported by a substrate, as well as on the contact load and sliding velocity. The results of the dynamic AFM experiments are corroborated by simulations, which show that the presence of a stiff substrate, increased load, and reduced sliding velocity lead to a more stable low-resistance contact.
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Lo KC, Hau KI, Chan WK. Photoconductivity enhancement and charge transport properties in ruthenium-containing block copolymer/carbon nanotube hybrids. NANOSCALE 2018; 10:6474-6486. [PMID: 29569662 DOI: 10.1039/c7nr09670d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Functional polymer/carbon nanotube (CNT) hybrid materials can serve as a good model for light harvesting systems based on CNTs. This paper presents the synthesis of block copolymer/CNT hybrids and the characterization of their photocurrent responses by both experimental and computational approaches. A series of functional diblock copolymers was synthesized by reversible addition-fragmentation chain transfer polymerizations for the dispersion and functionalization of CNTs. The block copolymers contain photosensitizing ruthenium complexes and modified pyrene-based anchoring units. The photocurrent responses of the polymer/CNT hybrids were measured by photoconductive atomic force microscopy (PCAFM), from which the experimental data were analyzed by vigorous statistical models. The difference in photocurrent response among different hybrids was correlated to the conformations of the hybrids, which were elucidated by molecular dynamics simulations, and the electronic properties of polymers. The photoresponse of the block copolymer/CNT hybrids can be enhanced by introducing an electron-accepting block between the photosensitizing block and the CNT. We have demonstrated that the application of a rigorous statistical methodology can unravel the charge transport properties of these hybrid materials and provide general guidelines for the design of molecular light harvesting systems.
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Affiliation(s)
- Kin Cheung Lo
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong.
| | - King In Hau
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong.
| | - Wai Kin Chan
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong.
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Mejía L, Renaud N, Franco I. Signatures of Conformational Dynamics and Electrode-Molecule Interactions in the Conductance Profile During Pulling of Single-Molecule Junctions. J Phys Chem Lett 2018; 9:745-750. [PMID: 29369638 DOI: 10.1021/acs.jpclett.7b03323] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We demonstrate that conductance can act as a sensitive probe of conformational dynamics and electrode-molecule interactions during the equilibrium and nonequilibrium pulling of molecular junctions. To do so, we use a combination of classical molecular dynamics simulations and Landauer electron transport computations to investigate the conductance of a family of Au-alkanedithiol-Au junctions as they are mechanically elongated. The simulations show an overall decay of the conductance during pulling that is due to a decrease in the through-space electrode-molecule interactions, and that sensitivity depends on the electrode geometry. In addition, characteristic kinks induced by level alignment shifts (and to a lesser extent by quantum destructive interference) were also observed superimposed to the overall decay during pulling simulations. The latter effect depends on the variation of the molecular dihedral angles during pulling and therefore offers an efficient solution to experimentally monitor conformational dynamics at the single-molecule limit.
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Affiliation(s)
- Leopoldo Mejía
- Department of Chemistry, University of Rochester , Rochester, New York 14627-0216, United States
| | - Nicolas Renaud
- Netherlands eScience Center , Science Park 140 1098 XG Amsterdam, The Netherlands
| | - Ignacio Franco
- Department of Chemistry, University of Rochester , Rochester, New York 14627-0216, United States
- Department of Physics, University of Rochester , Rochester, New York 14627-0216, United States
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41
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Cho D, Shekhar S, Lee H, Hong S. Nanoscale Mapping of Molecular Vibrational Modes via Vibrational Noise Spectroscopy. NANO LETTERS 2018; 18:1001-1009. [PMID: 29293349 DOI: 10.1021/acs.nanolett.7b04457] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We have developed a "vibrational noise spectroscopy (VNS)" method to identify and map vibrational modes of molecular wires on a solid substrate. In the method, electrical-noises generated in molecules on a conducting substrate were measured using a conducting atomic force microscopy (AFM) with a nanoresolution. We found that the bias voltage applied to the conducting AFM probe can stimulate specific vibrational modes of measured molecules, resulting in enhanced electrical noises. Thus, by analyzing noise-voltage spectra, we could identify various vibrational modes of the molecular wires on the substrates. Further, we could image the distribution of vibrational modes on molecule patterns on the substrates. In addition, we found that VNS imaging data could be further analyzed to quantitatively estimate the density of a specific vibrational mode in the layers of different molecular species. The VNS method allows one to measure molecular vibrational modes under ambient conditions with a nanoresolution, and thus it can be a powerful tool for nanoscale electronics and materials researches in general.
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Affiliation(s)
- Duckhyung Cho
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University , Seoul 08826, Korea
| | - Shashank Shekhar
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University , Seoul 08826, Korea
| | - Hyungwoo Lee
- Department of Materials Science and Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Seunghun Hong
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University , Seoul 08826, Korea
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42
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Diez-Cabanes V, Gonzalez SR, Osella S, Cornil D, Van Dyck C, Cornil J. Energy Level Alignment at Interfaces Between Au (111) and Thiolated Oligophenylenes of Increasing Chain Size: Theoretical Evidence of Pinning Effects. ADVANCED THEORY AND SIMULATIONS 2018. [DOI: 10.1002/adts.201700020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
| | | | - Silvio Osella
- Centre of New Technologies; University of Warsaw; Warszawa 02-097 Poland
| | - David Cornil
- Laboratory for Chemistry of Novel Materials; University of Mons; Mons 7000 Belgium
| | - Colin Van Dyck
- National Institute for Nanotechnology; Edmonton AB T6G 2M9 Canada
| | - Jérôme Cornil
- Laboratory for Chemistry of Novel Materials; University of Mons; Mons 7000 Belgium
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43
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Bâldea I. Floppy molecules as candidates for achieving optoelectronic molecular devices without skeletal rearrangement or bond breaking. Phys Chem Chem Phys 2018; 19:30842-30851. [PMID: 29135004 DOI: 10.1039/c7cp06428d] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Molecular species investigated as possible candidates for molecular photoswitches often toggle between two (low and high conductance) conformations implying skeletal rearrangement, bond breaking, and substantial changes of molecular length. All these represent shortcomings that impede the switching speed and straightforward incorporation in nanodevices. In the present paper we propose a mechanism wherein the photoinduced switching is from a nonplanar conformation to a planar conformation, and involves neither skeletal rearrangement nor bond breaking or significant molecular length changes. Specifically, by choosing typical floppy molecules consisting of two benzene or benzene-like rings that can easily rotate relative to each other, we present results of both ab initio and DFT quantum chemical calculations demonstrating that the lowest electronic excitation corresponds to a planar molecular conformation (φ = 0), in contrast to the nonplanar ground state characterized by φ ≠ 0. Because the low bias conductance scales as G ∝ cos2 φ, the planar conformation has a higher conductance than the non-planar conformation, acting therefore as ON and OFF states of the molecular switch, respectively. We analyze recent experimental data on illuminated single-molecule junctions (E.-D. Fung et al., Nano Lett., 2017, 17, 1255) and show that the measured photoinduced conductance enhancement is consistent with the presently proposed mechanism. Furthermore, based on recent results demonstrating the substantial impact of the SAM coverage on the twisting angle (I. Bâldea, Faraday Discuss., 2017, 204, 35) we show that a photoinduced conductance enhancement can be much stronger than the rather modest enhancement obtained in the aforementioned experiment.
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Affiliation(s)
- Ioan Bâldea
- Theoretische Chemie, Universität Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg, Germany
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44
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Cui L, Miao R, Wang K, Thompson D, Zotti LA, Cuevas JC, Meyhofer E, Reddy P. Peltier cooling in molecular junctions. NATURE NANOTECHNOLOGY 2018; 13:122-127. [PMID: 29255291 DOI: 10.1038/s41565-017-0020-z] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2017] [Accepted: 10/24/2017] [Indexed: 06/07/2023]
Abstract
The study of thermoelectricity in molecular junctions is of fundamental interest for the development of various technologies including cooling (refrigeration) and heat-to-electricity conversion 1-4 . Recent experimental progress in probing the thermopower (Seebeck effect) of molecular junctions 5-9 has enabled studies of the relationship between thermoelectricity and molecular structure 10,11 . However, observations of Peltier cooling in molecular junctions-a critical step for establishing molecular-based refrigeration-have remained inaccessible. Here, we report direct experimental observations of Peltier cooling in molecular junctions. By integrating conducting-probe atomic force microscopy 12,13 with custom-fabricated picowatt-resolution calorimetric microdevices, we created an experimental platform that enables the unified characterization of electrical, thermoelectric and energy dissipation characteristics of molecular junctions. Using this platform, we studied gold junctions with prototypical molecules (Au-biphenyl-4,4'-dithiol-Au, Au-terphenyl-4,4''-dithiol-Au and Au-4,4'-bipyridine-Au) and revealed the relationship between heating or cooling and charge transmission characteristics. Our experimental conclusions are supported by self-energy-corrected density functional theory calculations. We expect these advances to stimulate studies of both thermal and thermoelectric transport in molecular junctions where the possibility of extraordinarily efficient energy conversion has been theoretically predicted 2-4,14 .
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Affiliation(s)
- Longji Cui
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Ruijiao Miao
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Kun Wang
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Dakotah Thompson
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Linda Angela Zotti
- Departamento de Física Teórica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Madrid, Spain
| | - Juan Carlos Cuevas
- Departamento de Física Teórica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Madrid, Spain.
- Department of Physics, University of Konstanz, Konstanz, Germany.
| | - Edgar Meyhofer
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA.
| | - Pramod Reddy
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA.
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, USA.
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45
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Izawa S, Nakano K, Suzuki K, Chen Y, Kikitsu T, Hashizume D, Koganezawa T, Nguyen TQ, Tajima K. Crystallization and Polymorphism of Organic Semiconductor in Thin Film Induced by Surface Segregated Monolayers. Sci Rep 2018; 8:481. [PMID: 29323176 PMCID: PMC5764981 DOI: 10.1038/s41598-017-18881-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 12/18/2017] [Indexed: 11/21/2022] Open
Abstract
Preparation of highly crystalline organic semiconductor films is vital to achieving high performance in electronic devices. Here we report that surface segregated monolayers (SSMs) on top of phenyl-C61-butyric acid methyl ester (PCBM) thin films induce crystal growth in the bulk, resulting in a dramatic change in the structure to form a new crystal phase. Highly ordered crystalline films with large domain sizes of several hundreds of nanometers are formed with uniaxial orientation of the crystal structure perpendicular to the substrate. The molecular rearrangements in SSMs trigger the nucleation at a lower temperature than that for the spontaneous nucleation in PCBM. The vertical charge mobility in the SSM-induced crystal domains of PCBM is five times higher than in the ordinary polycrystalline domains. Using surface monolayers may be a new strategy for controlling crystal structures and obtaining high-quality organic thin films by post-deposition crystallization.
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Affiliation(s)
- Seiichiro Izawa
- RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
- Center for Polymers and Organic Solids, University of California, Santa Barbara, CA, 93106, USA
- Institute for Molecular Science, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi, 444-8787, Japan
| | - Kyohei Nakano
- RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Kaori Suzuki
- RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Yujiao Chen
- RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Tomoka Kikitsu
- RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Daisuke Hashizume
- RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Tomoyuki Koganezawa
- Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo-cho, Sayo, Hyogo, 679-5198, Japan
| | - Thuc-Quyen Nguyen
- Center for Polymers and Organic Solids, University of California, Santa Barbara, CA, 93106, USA
| | - Keisuke Tajima
- RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
- Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan.
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46
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Pulka-Ziach K, Sęk S. α-Helicomimetic foldamers as electron transfer mediators. NANOSCALE 2017; 9:14913-14920. [PMID: 28949361 DOI: 10.1039/c7nr05209j] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
α-Helical peptides are known as efficient mediators of electron transfer; however, their use is limited to compounds longer that 7-10 residues. To overcome this limitation, α-helicomimetic foldamers, based on the oligourea backbone with the general formula [-CH(R)-CH2-NH-CO-NH]n, were synthesized. Oligoureas are known to adopt a robust 2.5-helical conformation where only four residues are enough to form stable 1.5 helical turns. This feature makes them great models to study the charge transfer process and the dependence of the mechanism of the electron transition on the length of the mediator. Two families of different chain length (2, 4 and 6 residues) oligoureas were synthesized with a thiol group attached to the δ+ or δ- helix dipole pole. This enables the adsorption of the molecules onto the gold surface, leading to the formation of self-assembled monolayers. The helicity of compounds was confirmed in solution and in the solid state. Such systems were used to study the electron transfer process by current sensing atomic force microscopy (CS-AFM). The results showed that oligoureas may act as electron transfer mediators. Additionally, it was shown by the increasing force applied to the AFM tip that the oligourea helix is more stable than the helix formed by peptides.
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Affiliation(s)
- K Pulka-Ziach
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland.
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47
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Herrer L, Sebastian V, Martín S, González-Orive A, Pérez-Murano F, Low PJ, Serrano JL, Santamaría J, Cea P. High surface coverage of a self-assembled monolayer by in situ synthesis of palladium nanodeposits. NANOSCALE 2017; 9:13281-13290. [PMID: 28858363 DOI: 10.1039/c7nr03365f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Nascent metal|monolayer|metal devices have been fabricated by depositing palladium, produced through a CO-confined growth method, onto a self-assembled monolayer of an amine-terminated oligo(phenylene ethynylene) derivative on a gold bottom electrode. The high surface area coverage (85%) of the organic monolayer by densely packed palladium particles was confirmed by X-ray photoemission spectroscopy (XPS) and atomic force microscopy (AFM). The electrical properties of these nascent Au|monolayer|Pd assemblies were determined from the I-V curves recorded with a conductive-AFM using the Peak Force Tunneling AFM (PF-TUNA™) mode. The I-V curves together with the electrochemical experiments performed rule out the formation of short-circuits due to palladium penetration through the monolayer, suggesting that the palladium deposition strategy is an effective method for the fabrication of molecular junctions without damaging the organic layer.
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Affiliation(s)
- Lucía Herrer
- Instituto de Nanociencia de Aragón (INA), Campus Río Ebro, Universidad de Zaragoza, C/Mariano Esquillor, s/n, 50018 Zaragoza, Spain. and Laboratorio de Microscopias Avanzadas (LMA), Campus Río Ebro, Universidad de Zaragoza, C/Mariano Esquilor, s/n, 50018 Zaragoza, Spain and Departamento de Química Física, Facultad de Ciencias, Universidad de Zaragoza, 50009, Zaragoza, Spain
| | - Victor Sebastian
- Instituto de Nanociencia de Aragón (INA), Campus Río Ebro, Universidad de Zaragoza, C/Mariano Esquillor, s/n, 50018 Zaragoza, Spain. and Networking Biomedical Research Center of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), C/ Monforte de Lemos 3-5, Pabellón 11, 28029 Madrid, Spain and Departamento de Ingeniería Química y Tecnología del Medio Ambiente, Universidad de Zaragoza, C/Mariano Esquilor, s/n, 50018 Zaragoza, Spain
| | - Santiago Martín
- Departamento de Química Física, Facultad de Ciencias, Universidad de Zaragoza, 50009, Zaragoza, Spain and Instituto de Ciencia de Materiales de Aragón (ICMA), Universidad de Zaragoza-CSIC, 50009 Zaragoza, Spain
| | - Alejandro González-Orive
- Instituto de Nanociencia de Aragón (INA), Campus Río Ebro, Universidad de Zaragoza, C/Mariano Esquillor, s/n, 50018 Zaragoza, Spain. and Laboratorio de Microscopias Avanzadas (LMA), Campus Río Ebro, Universidad de Zaragoza, C/Mariano Esquilor, s/n, 50018 Zaragoza, Spain and Departamento de Química Física, Facultad de Ciencias, Universidad de Zaragoza, 50009, Zaragoza, Spain
| | - Francesc Pérez-Murano
- Instituto de Microelectrónica de Barcelona (IMB-CNM, CSIC), Campus UAB, 08193 Bellaterra, Spain
| | - Paul J Low
- School of Molecular Sciences, University of Western Australia, 35 Stirling Highway, Crawley, Perth 6009, Australia
| | - José Luis Serrano
- Instituto de Nanociencia de Aragón (INA), Campus Río Ebro, Universidad de Zaragoza, C/Mariano Esquillor, s/n, 50018 Zaragoza, Spain. and Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Zaragoza, 50009, Zaragoza, Spain
| | - Jesús Santamaría
- Instituto de Nanociencia de Aragón (INA), Campus Río Ebro, Universidad de Zaragoza, C/Mariano Esquillor, s/n, 50018 Zaragoza, Spain. and Networking Biomedical Research Center of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), C/ Monforte de Lemos 3-5, Pabellón 11, 28029 Madrid, Spain and Departamento de Ingeniería Química y Tecnología del Medio Ambiente, Universidad de Zaragoza, C/Mariano Esquilor, s/n, 50018 Zaragoza, Spain
| | - Pilar Cea
- Instituto de Nanociencia de Aragón (INA), Campus Río Ebro, Universidad de Zaragoza, C/Mariano Esquillor, s/n, 50018 Zaragoza, Spain. and Laboratorio de Microscopias Avanzadas (LMA), Campus Río Ebro, Universidad de Zaragoza, C/Mariano Esquilor, s/n, 50018 Zaragoza, Spain and Departamento de Química Física, Facultad de Ciencias, Universidad de Zaragoza, 50009, Zaragoza, Spain
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48
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Zhang Y, Qiu X, Gordiichuk P, Soni S, Krijger TL, Herrmann A, Chiechi RC. Mechanically and Electrically Robust Self-Assembled Monolayers for Large-Area Tunneling Junctions. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2017; 121:14920-14928. [PMID: 28729893 PMCID: PMC5512119 DOI: 10.1021/acs.jpcc.7b03853] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 06/12/2017] [Indexed: 05/28/2023]
Abstract
This paper examines the relationship between mechanical deformation and the electronic properties of self-assembled monolayers (SAMs) of the oligothiophene 4-([2,2':5',2″:5″,2‴-quaterthiophen]-5-yl)butane-1-thiol (T4C4) in tunneling junctions using conductive probe atomic force microscopy (CP-AFM) and eutectic Ga-In (EGaIn). We compared shifts in conductivity, transition voltages of T4C4 with increasing AFM tip loading force to alkanethiolates. While these shifts result from an increasing tilt angle from penetration of the SAM by the AFM tip for the latter, we ascribe them to distortions of the π system present in T4C4, which is more mechanically robust than alkanethiolates of comparable length; SAMs comprising T4C4 shows about five times higher Young's modulus than alkanethiolates. Density functional theory calculations confirm that mechanical deformations shift the barrier height due to changes in the frontier orbitals caused by small rearrangements to the conformation of the quaterthiophene moiety. The mechanical robustness of T4C4 manifests as an increased tolerance to high bias in large-area EGaIn junctions suggesting that electrostatic pressure plays a significant role in the shorting of molecular junctions at high bias.
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Affiliation(s)
- Yanxi Zhang
- Stratingh
Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
- Zernike
Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Xinkai Qiu
- Stratingh
Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
- Zernike
Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Pavlo Gordiichuk
- Zernike
Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Saurabh Soni
- Stratingh
Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
- Zernike
Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Theodorus L. Krijger
- Stratingh
Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
- Zernike
Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Andreas Herrmann
- Zernike
Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Ryan C. Chiechi
- Stratingh
Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
- Zernike
Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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49
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Kaur RP, Sawhney RS, Engles D. First principle electron transport modeling of Be-doped organic molecular junctions. J Mol Graph Model 2017; 75:199-208. [PMID: 28586702 DOI: 10.1016/j.jmgm.2017.05.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 05/23/2017] [Accepted: 05/24/2017] [Indexed: 11/24/2022]
Abstract
The transport properties of beryllium doped anthracene molecular junction are investigated using density functional non-equillibrium Green's function method. The equilibrium conductance of anthracene Metal-molecule-Metal (MmM) junction increases by approximately 77% by adding beryllium impurity to it. The electronic transport characteristics under both zero bias as well as finite bias are explored of such molecular junction. We observe novel attributes such as molecular rectification and NDR behavior for the molecular junction under consideration. It is found that the doping effect of Be- atom significantly changes the transport properties of aromatic molecular junction. Our findings shed light on the electron transport metrics that affect the conductance of MmM junctions within appreciable transmission limits. We firmly believe that the results deduced in this paper can be generalized for other aromatic molecular junctions as well.
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Affiliation(s)
- Rupan Preet Kaur
- Department of Electronics Technology, Guru Nanak Dev University, Amritsar, India.
| | | | - Derick Engles
- Department of Electronics Technology, Guru Nanak Dev University, Amritsar, India.
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50
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Zhou Q, Yamada A, Feng Q, Hoskins A, Dunietz BD, Lewis KM. Modification of Molecular Conductance by in Situ Deprotection of Thiol-Based Porphyrin. ACS APPLIED MATERIALS & INTERFACES 2017; 9:15901-15906. [PMID: 28332399 DOI: 10.1021/acsami.6b14841] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Acetylthio-protected free base porphyrins are used to form scanning tunneling microscope-molecular break junctions. The porphyrin molecules are deprotected in situ, before the self-assembly. Two types of molecular junctions are formed in the junctions: Au-S-Por-SAc-Au and Au-S-Por-S-Au. Lower conductance values and higher conductance values are observed. Computational modeling attributes the lower conductance to the Au-S-Por-SAc-Au junctions and the higher conductance to the Au-S-Por-S-Au junctions. First-principles calculation suggests that the reduced conductance in the protected porphyrin originates from the presence of the acetyl end groups (-COCH3), rather than from the elongation of the sulfur-gold (S-Au) bonds at the tip-molecule interface.
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Affiliation(s)
- Qi Zhou
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute , Troy, New York 12180, United States
| | - Atsushi Yamada
- Department of Chemistry and Biochemistry, Kent State University , Kent, Ohio 44242, United States
| | - Qingguo Feng
- Department of Chemistry and Biochemistry, Kent State University , Kent, Ohio 44242, United States
| | - Austin Hoskins
- Department of Chemistry and Biochemistry, Kent State University , Kent, Ohio 44242, United States
| | - Barry D Dunietz
- Department of Chemistry and Biochemistry, Kent State University , Kent, Ohio 44242, United States
| | - Kim M Lewis
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute , Troy, New York 12180, United States
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