1
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de Ara T, Hsu C, Martinez-Garcia A, Baciu BC, Bronk PJ, Ornago L, van der Poel S, Lombardi EB, Guijarro A, Sabater C, Untiedt C, van der Zant HSJ. Evidence of an Off-Resonant Electronic Transport Mechanism in Helicenes. J Phys Chem Lett 2024; 15:8343-8350. [PMID: 39110695 PMCID: PMC11331518 DOI: 10.1021/acs.jpclett.4c01425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2024] [Revised: 07/30/2024] [Accepted: 07/31/2024] [Indexed: 08/16/2024]
Abstract
Helical molecules have been proposed as candidates for producing spin-polarized currents, even at room conditions, due to their chiral asymmetry. However, describing their transport mechanism in single molecular junctions is not straightforward. In this work, we show the synthesis of two novel kinds of dithia[11]helicenes to study their electronic transport in break junctions among a series of three helical molecules: dithia[n]helicenes, with n = 7, 9, and 11 molecular units. Our experimental measurements and clustering-based analysis demonstrate low conductance values that remain similar across different applied voltages and molecules. Additionally, we assess the length dependence of the conductance for each helicene, revealing an exponential decay characteristic of off-resonant transport. This behavior is primarily attributed to the misalignment between the energy levels of the molecule-electrodes system. The length dependence trend described above is supported by ab initio calculations, further confirming an off-resonant transport mechanism.
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Affiliation(s)
- T. de Ara
- Departamento
de Física Aplicada and Instituto Universitario de Materiales
de Alicante (IUMA), Universidad de Alicante, Campus de San Vicente del Raspeig, E-03690 Alicante, Spain
| | - C. Hsu
- Department
of Quantum Nanoscience, Delft University
of Technology, Delft 2628CJ, The Netherlands
| | - A. Martinez-Garcia
- Departamento
de Física Aplicada and Instituto Universitario de Materiales
de Alicante (IUMA), Universidad de Alicante, Campus de San Vicente del Raspeig, E-03690 Alicante, Spain
| | - B. C. Baciu
- Departamento
de Química Orgánica and Instituto Universitario de Síntesis
Orgánica, Universidad de Alicante, Campus de San Vicente del Raspeig, E-03690 Alicante, Spain
| | - P. J. Bronk
- Departamento
de Química Orgánica and Instituto Universitario de Síntesis
Orgánica, Universidad de Alicante, Campus de San Vicente del Raspeig, E-03690 Alicante, Spain
| | - L. Ornago
- Department
of Quantum Nanoscience, Delft University
of Technology, Delft 2628CJ, The Netherlands
| | - S. van der Poel
- Department
of Quantum Nanoscience, Delft University
of Technology, Delft 2628CJ, The Netherlands
| | - E. B. Lombardi
- Department
of Physics, Florida Science Campus, University
of South Africa, Florida Park, Johannesburg 1710, South Africa
| | - A. Guijarro
- Departamento
de Química Orgánica and Instituto Universitario de Síntesis
Orgánica, Universidad de Alicante, Campus de San Vicente del Raspeig, E-03690 Alicante, Spain
| | - C. Sabater
- Departamento
de Física Aplicada and Instituto Universitario de Materiales
de Alicante (IUMA), Universidad de Alicante, Campus de San Vicente del Raspeig, E-03690 Alicante, Spain
| | - C. Untiedt
- Departamento
de Física Aplicada and Instituto Universitario de Materiales
de Alicante (IUMA), Universidad de Alicante, Campus de San Vicente del Raspeig, E-03690 Alicante, Spain
| | - H. S. J. van der Zant
- Department
of Quantum Nanoscience, Delft University
of Technology, Delft 2628CJ, The Netherlands
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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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Chen N, Li S, Zhao P, Liu R, Xie Y, Lin JL, Nijhuis CA, Xu B, Zhang L, Xu H, Li Y. Extreme long-lifetime self-assembled monolayer for air-stable molecular junctions. SCIENCE ADVANCES 2023; 9:eadh3412. [PMID: 37851815 PMCID: PMC10584343 DOI: 10.1126/sciadv.adh3412] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Accepted: 09/14/2023] [Indexed: 10/20/2023]
Abstract
The molecular electronic devices based on self-assembled monolayer (SAM) on metal surfaces demonstrate novel electronic functions for device minimization yet are unable to realize in practical applications, due to their instability against oxidation of the sulfur-metal bond. This paper describes an alternative to the thiolate anchoring group to form stable SAMs on gold by selenides anchoring group. Because of the formation of strong selenium-gold bonds, these stable SAMs allow us to incorporate them in molecular tunnel junctions to yield extremely stable junctions for over 200 days. A detailed structural characterization supported by spectroscopy and first-principles modeling shows that the oxidation process is much slower with the selenium-gold bond than the sulfur-gold bond, and the selenium-gold bond is strong enough to avoid bond breaking even when it is eventually oxidized. This proof of concept demonstrates that the extraordinarily stable SAMs derived from selenides are useful for long-lived molecular electronic devices and can possibly become important in many air-stable applications involving SAMs.
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Affiliation(s)
- Ningyue Chen
- Key Laboratory of Organic Optoelectronics and Molecular Engineering and Laboratory of Flexible Electronics Technology, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Shuwei Li
- Center for Combustion Energy, Tsinghua University, Beijing 100084, China
- School of Vehicle and Mobility, and State Key Laboratory of Intelligent Green Vehicle and Mobility, Tsinghua University, Beijing 100084, China
| | - Peng Zhao
- Key Laboratory of Organic Optoelectronics and Molecular Engineering and Laboratory of Flexible Electronics Technology, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Ran Liu
- School of Electrical and Computer Engineering, University of Georgia, Athens, GA 30602, USA
| | - Yu Xie
- Key Laboratory of Organic Optoelectronics and Molecular Engineering and Laboratory of Flexible Electronics Technology, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Jin-Liang Lin
- Key Laboratory of Organic Optoelectronics and Molecular Engineering and Laboratory of Flexible Electronics Technology, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Christian A. Nijhuis
- Hybrid Materials for Opto-Electronics Group, Department of Molecules and Materials, MESA+ Institute for Nanotechnology, Molecules Centre and Centre for Brain-Inspired Nano Systems, Faculty of Science and Technology, University of Twente, 7500 AE Enschede, Netherlands
| | - Bingqian Xu
- School of Electrical and Computer Engineering, University of Georgia, Athens, GA 30602, USA
| | - Liang Zhang
- Center for Combustion Energy, Tsinghua University, Beijing 100084, China
- School of Vehicle and Mobility, and State Key Laboratory of Intelligent Green Vehicle and Mobility, Tsinghua University, Beijing 100084, China
| | - Huaping Xu
- Key Laboratory of Organic Optoelectronics and Molecular Engineering and Laboratory of Flexible Electronics Technology, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Yuan Li
- Key Laboratory of Organic Optoelectronics and Molecular Engineering and Laboratory of Flexible Electronics Technology, Department of Chemistry, Tsinghua University, Beijing 100084, China
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4
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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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5
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Pan X, Qian C, Chow A, Wang L, Kamenetska M. Atomically precise binding conformations of adenine and its variants on gold using single molecule conductance signatures. J Chem Phys 2022; 157:234201. [PMID: 36550043 DOI: 10.1063/5.0103642] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
We demonstrate single molecule conductance as a sensitive and atomically precise probe of binding configurations of adenine and its biologically relevant variants on gold. By combining experimental measurements and density functional theory (DFT) calculations of single molecule-metal junction structures in aqueous conditions, we determine for the first time that robust binding of adenine occurs in neutral or basic pH when the molecule is deprotonated at the imidazole moiety. The molecule binds through the donation of the electron lone pairs from the imidazole nitrogen atoms, N7 and N9, to the gold electrodes. In addition, the pyrimidine ring nitrogen, N3, can bind concurrently and strengthen the overall metal-molecule interaction. The amine does not participate in binding to gold in contrast to most other amine-terminated molecular wires due to the planar geometry of the nucleobase. DFT calculations reveal the importance of interface charge transfer in stabilizing the experimentally observed binding configurations. We demonstrate that biologically relevant variants of adenine, 6-methyladenine and 2'-deoxyadenosine, have distinct conductance signatures. These results lay the foundation for biosensing on gold using single molecule conductance readout.
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Affiliation(s)
- Xiaoyun Pan
- Department of Chemistry, Boston University, 590 Commonwealth Ave., Boston, Massachusetts 02215, USA
| | - Cheng Qian
- Department of Chemistry and Chemical Biology, Institute for Quantitative Biomedicine, Rutgers University, 174 Frelinghuysen Road, Piscataway, New Jersey 08854, USA
| | - Amber Chow
- Department of Physics, Boston University, 590 Commonwealth Ave., Boston, Massachusetts 02215, USA
| | - Lu Wang
- Department of Chemistry and Chemical Biology, Institute for Quantitative Biomedicine, Rutgers University, 174 Frelinghuysen Road, Piscataway, New Jersey 08854, USA
| | - Maria Kamenetska
- Department of Chemistry, Boston University, 590 Commonwealth Ave., Boston, Massachusetts 02215, USA
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6
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Mitra G, Delmas V, Al Sabea H, Norel L, Galangau O, Rigaut S, Cornil J, Costuas K, Scheer E. Electronic transport through single-molecule oligophenyl-diethynyl junctions with direct gold-carbon bonds formed at low temperature. NANOSCALE ADVANCES 2022; 4:457-466. [PMID: 36132702 PMCID: PMC9419624 DOI: 10.1039/d1na00650a] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 11/27/2021] [Indexed: 06/16/2023]
Abstract
We report on the first systematic transport study of alkynyl-ended oligophenyl-diethynyl (OPA) single-molecule junctions with direct Au-C anchoring scheme at low temperature using the mechanically controlled break junction technique. Through quantitative statistical analysis of opening traces, conductance histograms and density functional theory studies, we identified different types of junctions, classified by their conductance and stretching behavior, for OPA molecules between Au electrodes with two to four phenyl rings. We performed inelastic electron tunneling spectroscopy and observed the excitation of Au-C vibrational modes confirming the existence of Au-C bonds at low temperature and compared the stability of molecule junctions upon mechanical stretching. Our findings reveal the huge potential for future functional molecule transport studies at low temperature using alkynyl endgroups.
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Affiliation(s)
- Gautam Mitra
- University of Konstanz, Department of Physics 78 457 Konstanz Germany
| | - Vincent Delmas
- Univ. Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes), UMR 6226 F-35 000 Rennes France
| | - Hassan Al Sabea
- Univ. Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes), UMR 6226 F-35 000 Rennes France
| | - Lucie Norel
- Univ. Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes), UMR 6226 F-35 000 Rennes France
| | - Olivier Galangau
- Univ. Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes), UMR 6226 F-35 000 Rennes France
| | - Stéphane Rigaut
- Univ. Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes), UMR 6226 F-35 000 Rennes France
| | - Jérôme Cornil
- University of Mons, Laboratory for Chemistry of Novel Materials, Department of Chemistry Place du Parc 20 B-7000 Mons Belgium
| | - Karine Costuas
- Univ. Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes), UMR 6226 F-35 000 Rennes France
| | - Elke Scheer
- University of Konstanz, Department of Physics 78 457 Konstanz Germany
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7
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Tian L, Martine E, Yu X, Hu W. Amine-Anchored Aromatic Self-Assembled Monolayer Junction: Structure and Electric Transport Properties. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:12223-12233. [PMID: 34606290 DOI: 10.1021/acs.langmuir.1c02194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We studied the structure and transport properties of aromatic amine self-assembled monolayers (NH2-SAMs) on an Au surface. The oligophenylene and oligoacene amines with variable lengths can form a densely packed and uniform monolayer under proper assembly conditions. Molecular junctions incorporating an eutectic Ga-In (EGaIn) top electrode were used to characterize the charge transport properties of the amine monolayer. The current density J of the junction decreases exponentially with the molecular length (d), as J = J0 exp(-βd), which is a sign of tunneling transport, with indistinguishable values of J0 and β for NH2-SAMs of oligophenylene and oligoacene, indicating a similar molecule-electrode contact and tunneling barrier for two groups of molecules. Compared with the oligophenylene and oligoacene molecules with thiol (SH) as the anchor group, a similar β value (∼0.35 Å-1) of the aromatic NH2-SAM suggests a similar tunneling barrier, while a lower (by 2 orders of magnitude) injection current J0 is attributed to lower electronic coupling Γ of the amine group with the electrode. These observations are further supported by single-level tunneling model fitting. Our study here demonstrates the NH2-SAMs can work as an effective active layer for molecular junctions, and provide key physical parameters for the charge transport, paving the road for their applications in functional devices.
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Affiliation(s)
- Lixian Tian
- Tianjin Key Laboratory of Molecular Optoelectronic Science, School of Science, Tianjin University & Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, China
| | - Esther Martine
- Tianjin Key Laboratory of Molecular Optoelectronic Science, School of Science, Tianjin University & Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, China
| | - Xi Yu
- Tianjin Key Laboratory of Molecular Optoelectronic Science, School of Science, Tianjin University & Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, China
| | - Wenping Hu
- Tianjin Key Laboratory of Molecular Optoelectronic Science, School of Science, Tianjin University & Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, China
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8
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Chiang KR, Tang YH. Effect of Contact Geometry on Spin Transport in Amine-Ended Single-Molecule Magnetic Junctions. ACS OMEGA 2021; 6:19386-19391. [PMID: 34368525 PMCID: PMC8340092 DOI: 10.1021/acsomega.1c00930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Accepted: 07/13/2021] [Indexed: 06/13/2023]
Abstract
We employ the first-principles calculation with non-equilibrium Green's function method to comprehensively investigate the crucial role of interfacial geometry in spin transport properties of Co/1,4-benzenediamine (BDA)/Co single-molecule magnetic junctions (SMMJs). Two bonding mechanisms are proposed for the hard-hard Co-N coupling: (1) the covalent bonding between the H-dissociated amine linker and spin-polarized Co apex atoms and (2) the dative interaction between the H-non-dissociated (denoted by +H) amine linker and Co apex atoms. The former covalent contact dominates the π-resonance interfacial spin selection that can be well preserved in H-dissociated cases regardless of the choice of top, bridge, and hollow contact sites. From our detailed analyses of spin-polarized transmission spectra, local density of states, and molecular density of states, the underlying mechanism is that the strong hybridization between Co-d, N-p y , and the π-orbital of the phenyl ring in dissociated cases renders the 2-fold HOMO (4-fold LUMO) of the central molecule closer to the Fermi energy. In contrast, the enlarged Co-N bond length of the latter dative contact in the H-non-dissociated case not only destroys the spinterface coupling but also blocks the spin injection. This theoretical work may provide vital and practical insights to illustrate the spin transport property in real amine-ended SMMJs since the contact geometries and interfacial bond mechanisms remain unclear during the breaking junction technique.
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Affiliation(s)
- Kuan-Rong Chiang
- Department of Physics, National
Central University, Jung-Li 32001, Taiwan
| | - Yu-Hui Tang
- Department of Physics, National
Central University, Jung-Li 32001, Taiwan
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9
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Kim Y. Photoswitching Molecular Junctions: Platforms and Electrical Properties. Chemphyschem 2020; 21:2368-2383. [PMID: 32777151 DOI: 10.1002/cphc.202000564] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 08/07/2020] [Indexed: 11/10/2022]
Abstract
Remarkable advances in technology have enabled the manipulation of individual molecules and the creation of molecular electronic devices utilizing single and ensemble molecules. Maturing the field of molecular electronics has led to the development of functional molecular devices, especially photoswitching or photochromic molecular junctions, which switch electronic properties under external light irradiation. This review introduces and summarizes the platforms for investigating the charge transport in single and ensemble photoswitching molecular junctions as well as the electronic properties of diverse photoswitching molecules such as diarylethene, azobenzene, dihydropyrene, and spiropyran. Furthermore, the article discusses the remaining challenges and the direction for moving forward in this area for future photoswitching molecular devices.
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Affiliation(s)
- Youngsang Kim
- Lawrence Berkeley National Laboratory, Berkeley, California, 94720, USA.,Current address, 7644 Ambrose way, California, 95831, USA
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10
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Mezei G, Balogh Z, Magyarkuti A, Halbritter A. Voltage-Controlled Binary Conductance Switching in Gold-4,4'-Bipyridine-Gold Single-Molecule Nanowires. J Phys Chem Lett 2020; 11:8053-8059. [PMID: 32893638 PMCID: PMC7528405 DOI: 10.1021/acs.jpclett.0c02185] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
We investigate gold-4,4'-bipyridine-gold single-molecule junctions with the mechanically controllable break junction technique at cryogenic temperature (T = 4.2 K). We observe bistable probabilistic conductance switching between the two molecular binding configurations, influenced both by the mechanical actuation and by the applied voltage. We demonstrate that the relative dominance of the two conductance states is tunable by the electrode displacement, whereas the voltage manipulation induces an exponential speedup of both switching times. The detailed investigation of the voltage-tunable switching rates provides an insight into the possible switching mechanisms.
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Affiliation(s)
- G. Mezei
- Department
of Physics, Budapest University of Technology
and Economics, 1111 Budapest, Budafoki ut 8., Hungary
- MTA-BME
Condensed Matter Research Group, Budafoki
ut 8, 1111 Budapest, Hungary
| | - Z. Balogh
- Department
of Physics, Budapest University of Technology
and Economics, 1111 Budapest, Budafoki ut 8., Hungary
- MTA-BME
Condensed Matter Research Group, Budafoki
ut 8, 1111 Budapest, Hungary
| | - A. Magyarkuti
- Department
of Physics, Budapest University of Technology
and Economics, 1111 Budapest, Budafoki ut 8., Hungary
- MTA-BME
Condensed Matter Research Group, Budafoki
ut 8, 1111 Budapest, Hungary
| | - A. Halbritter
- Department
of Physics, Budapest University of Technology
and Economics, 1111 Budapest, Budafoki ut 8., Hungary
- MTA-BME
Condensed Matter Research Group, Budafoki
ut 8, 1111 Budapest, Hungary
- E-mail:
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11
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Kobayashi S, Kaneko S, Kiguchi M, Tsukagoshi K, Nishino T. Tolerance to Stretching in Thiol-Terminated Single-Molecule Junctions Characterized by Surface-Enhanced Raman Scattering. J Phys Chem Lett 2020; 11:6712-6717. [PMID: 32619093 DOI: 10.1021/acs.jpclett.0c01526] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We investigated the change in the metal-molecule interaction in a 1,4-benzenedithiol (BDT) single-molecule junction using a combination of surface-enhanced Raman scattering spectra and current-voltage curves. During the stretching process, the conductance of the junction systematically decreased, accompanied by an increase in the vibrational energy of the CC stretching mode. By analyzing the current-voltage curves and Raman spectra, we found that the interaction between the π orbital of BDT and the electronic states of Au was diminished by the orientation change of BDT during the stretching process. A comparison with a 4,4'-bipyridine single-molecule junction revealed that the reduction of coupling of the Au-S contacts was smaller than that of Au-pyridine contacts. Therefore, the electronic states originating from the contact geometry are responsible for the tolerance to the stretching of thiol-terminated molecular junctions.
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Affiliation(s)
- S Kobayashi
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 W4-10 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
| | - S Kaneko
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 W4-10 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
- JST PRESTO, 4-1-8 Honcho, Kawaguchi 332-0012, Japan
| | - M Kiguchi
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 W4-10 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
| | - K Tsukagoshi
- International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), 1-1 Tsukuba, Ibaraki 305-0044, Japan
| | - T Nishino
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 W4-10 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
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12
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Pan X, Lawson B, Rustad AM, Kamenetska M. pH-Activated Single Molecule Conductance and Binding Mechanism of Imidazole on Gold. NANO LETTERS 2020; 20:4687-4692. [PMID: 32364746 DOI: 10.1021/acs.nanolett.0c01710] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We identify imidazole as a pH-activated linker for forming stable single molecule-gold junctions with several distinct configurations and reproducible electrical characteristics. Using a scanning tunneling microscope break junction (STMBJ) technique, we find multiple robust conductance signatures at integer multiples of 1.9 × 10-2G0 and 1.2 × 10-4G0 and determine that this molecule bridges the electrodes in its deprotonated form through the nitrogen atoms in basic conditions only, with several molecules able to bind in parallel and in series. The elongation these junctions can sustain is longer than the length of the molecule, suggesting that plastic deformation of gold electrodes occurs during stretching. Density functional theory calculations confirm that the imidazolate-linked junctions exhibit bond strengths of ∼2 eV, which can allow for plastic extraction of gold atoms. On the basis of these results, we hypothesize that lower conductance peaks correspond to chains of repeating molecule-gold units that we form and measure in situ.
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13
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Optoplasmonic characterisation of reversible disulfide interactions at single thiol sites in the attomolar regime. Nat Commun 2020; 11:2043. [PMID: 32341342 PMCID: PMC7184569 DOI: 10.1038/s41467-020-15822-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 03/26/2020] [Indexed: 12/14/2022] Open
Abstract
Probing individual chemical reactions is key to mapping reaction pathways. Trace analysis of sub-kDa reactants and products is obfuscated by labels, however, as reaction kinetics are inevitably perturbed. The thiol-disulfide exchange reaction is of specific interest as it has many applications in nanotechnology and in nature. Redox cycling of single thiols and disulfides has been unresolvable due to a number of technological limitations, such as an inability to discriminate the leaving group. Here, we demonstrate detection of single-molecule thiol-disulfide exchange using a label-free optoplasmonic sensor. We quantify repeated reactions between sub-kDa thiolated species in real time and at concentrations down to 100’s of attomolar. A unique sensing modality is featured in our measurements, enabling the observation of single disulfide reaction kinetics and pathways on a plasmonic nanoparticle surface. Our technique paves the way towards characterising molecules in terms of their charge, oxidation state, and chirality via optoplasmonics. Visualising single-molecule reactions, to understand their mechanisms, is a challenging task. Here, the authors investigate disulfide exchange reactions with thiolates immobilised on a gold nanoparticle through a label-free optoplasmonic sensor, and detect individual disulfide interactions in solution
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14
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Zhao Z, Liu R, Mayer D, Coppola M, Sun L, Kim Y, Wang C, Ni L, Chen X, Wang M, Li Z, Lee T, Xiang D. Shaping the Atomic-Scale Geometries of Electrodes to Control Optical and Electrical Performance of Molecular Devices. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2018; 14:e1703815. [PMID: 29542239 DOI: 10.1002/smll.201703815] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 02/16/2018] [Indexed: 05/27/2023]
Abstract
A straightforward method to generate both atomic-scale sharp and atomic-scale planar electrodes is reported. The atomic-scale sharp electrodes are generated by precisely stretching a suspended nanowire, while the atomic-scale planar electrodes are obtained via mechanically controllable interelectrodes compression followed by a thermal-driven atom migration process. Notably, the gap size between the electrodes can be precisely controlled at subangstrom accuracy with this method. These two types of electrodes are subsequently employed to investigate the properties of single molecular junctions. It is found, for the first time, that the conductance of the amine-linked molecular junctions can be enhanced ≈50% as the atomic-scale sharp electrodes are used. However, the atomic-scale planar electrodes show great advantages to enhance the sensitivity of Raman scattering upon the variation of nanogap size. The underlying mechanisms for these two interesting observations are clarified with the help of density functional theory calculation and finite-element method simulation. These findings not only provide a strategy to control the electron transport through the molecule junction, but also pave a way to modulate the optical response as well as to improve the stability of single molecular devices via the rational design of electrodes geometries.
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Affiliation(s)
- Zhikai Zhao
- Key Laboratory of Optical Information Science and Technology, Institute of Modern Optics, College of Electronic Information and Optical Engineering, Nankai University, Nankai, 300071, China
| | - Ran Liu
- School of Physics and Electronics, Shandong Normal University, Jinan, 250014, China
| | - Dirk Mayer
- Peter-Grünberg-Institute PGI-8, Bioelectronic Research Center Jülich GmbH and JARA, Fundamentals of Future Information Technology, Jülich, 52425, Germany
| | - Maristella Coppola
- Peter-Grünberg-Institute PGI-8, Bioelectronic Research Center Jülich GmbH and JARA, Fundamentals of Future Information Technology, Jülich, 52425, Germany
| | - Lu Sun
- Key Laboratory of Optical Information Science and Technology, Institute of Modern Optics, College of Electronic Information and Optical Engineering, Nankai University, Nankai, 300071, China
| | - Youngsang Kim
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Chuankui Wang
- School of Physics and Electronics, Shandong Normal University, Jinan, 250014, China
| | - Lifa Ni
- Key Laboratory of Optical Information Science and Technology, Institute of Modern Optics, College of Electronic Information and Optical Engineering, Nankai University, Nankai, 300071, China
| | - Xing Chen
- Penn State Department of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, PA, 16802, USA
| | - Maoning Wang
- Key Laboratory of Optical Information Science and Technology, Institute of Modern Optics, College of Electronic Information and Optical Engineering, Nankai University, Nankai, 300071, China
| | - Zongliang Li
- School of Physics and Electronics, Shandong Normal University, Jinan, 250014, China
| | - Takhee Lee
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea
| | - Dong Xiang
- Key Laboratory of Optical Information Science and Technology, Institute of Modern Optics, College of Electronic Information and Optical Engineering, Nankai University, Nankai, 300071, China
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15
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Sangtarash S, Vezzoli A, Sadeghi H, Ferri N, O'Brien HM, Grace I, Bouffier L, Higgins SJ, Nichols RJ, Lambert CJ. Gateway state-mediated, long-range tunnelling in molecular wires. NANOSCALE 2018; 10:3060-3067. [PMID: 29376529 DOI: 10.1039/c7nr07243k] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
If the factors controlling the decay in single-molecule electrical conductance G with molecular length L could be understood and controlled, then this would be a significant step forward in the design of high-conductance molecular wires. For a wide variety of molecules conducting by phase coherent tunnelling, conductance G decays with length following the relationship G = Ae-βL. It is widely accepted that the attenuation coefficient β is determined by the position of the Fermi energy of the electrodes relative to the energy of frontier orbitals of the molecular bridge, whereas the terminal anchor groups which bind to the molecule to the electrodes contribute to the pre-exponential factor A. We examine this premise for several series of molecules which contain a central conjugated moiety (phenyl, viologen or α-terthiophene) connected on either side to alkane chains of varying length, with each end terminated by thiol or thiomethyl anchor groups. In contrast with this expectation, we demonstrate both experimentally and theoretically that additional electronic states located on thiol anchor groups can significantly decrease the value of β, by giving rise to resonances close to EF through coupling to the bridge moiety. This interplay between the gateway states and their coupling to a central conjugated moiety in the molecular bridges creates a new design strategy for realising higher-transmission molecular wires by taking advantage of the electrode-molecule interface properties.
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Affiliation(s)
- Sara Sangtarash
- Quantum Technology Centre, Physics Department, Lancaster University, Lancaster LA1 4YB, UK.
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16
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17
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Zhang Q, Tao S, Yi R, He C, Zhao C, Su W, Smogunov A, Dappe YJ, Nichols RJ, Yang L. Symmetry Effects on Attenuation Factors in Graphene-Based Molecular Junctions. J Phys Chem Lett 2017; 8:5987-5992. [PMID: 29178793 DOI: 10.1021/acs.jpclett.7b02822] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The unique structural and electronic characteristics of graphene make it an attractive contact for fundamental single-molecule electrical studies. With this in mind, we have probed here the electrical conductance of a molecular junction based on α,ω-diaminoalkane chains sandwiched between a gold and a graphene electrode. Using an STM based I(s) method combined with density functional theory-based transport calculations, we demonstrate that the resulting attenuation factor turns out to be much lower when compared to the standard molecular junction between two gold electrodes. This effect is attributed to asymmetric coupling of the molecule through strong chemisorption at the gold electrode and weaker van der Waals contact at graphene. Moreover, this asymmetric coupling induces higher conductance than that in the same hybrid metal-graphene molecular junction using standard thiol anchoring groups.
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Affiliation(s)
- Qian Zhang
- Department of Chemistry, Xi'an-Jiaotong Liverpool University , 215123 Suzhou, China
- Department of Chemistry, University of Liverpool , Liverpool L69 7ZD, United Kingdom
| | - Shuhui Tao
- Department of Chemistry, Xi'an-Jiaotong Liverpool University , 215123 Suzhou, China
- Department of Chemistry, University of Liverpool , Liverpool L69 7ZD, United Kingdom
| | - Ruowei Yi
- Department of Chemistry, Xi'an-Jiaotong Liverpool University , 215123 Suzhou, China
- Department of Chemistry, University of Liverpool , Liverpool L69 7ZD, United Kingdom
| | - Chunhui He
- Department of Chemistry, Xi'an-Jiaotong Liverpool University , 215123 Suzhou, China
- Department of Chemistry, University of Liverpool , Liverpool L69 7ZD, United Kingdom
| | - Cezhou Zhao
- Department of Electrical and Electronic Engineering, Xi'an-Jiaotong Liverpool University , 215123 Suzhou, China
| | - Weitao Su
- College of Materials and Environmental Engineering, Hangzhou Dianzi University , 310018 Hangzhou, China
| | - Alexander Smogunov
- SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay , 91191 Gif-sur-Yvette, Cedex, France
| | - Yannick J Dappe
- SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay , 91191 Gif-sur-Yvette, Cedex, France
| | - Richard J Nichols
- Department of Chemistry, University of Liverpool , Liverpool L69 7ZD, United Kingdom
| | - Li Yang
- Department of Chemistry, Xi'an-Jiaotong Liverpool University , 215123 Suzhou, China
- Department of Chemistry, University of Liverpool , Liverpool L69 7ZD, United Kingdom
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18
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Kim Y, Bahoosh SG, Sysoiev D, Huhn T, Pauly F, Scheer E. Inelastic electron tunneling spectroscopy of difurylethene-based photochromic single-molecule junctions. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2017; 8:2606-2614. [PMID: 29259875 PMCID: PMC5727803 DOI: 10.3762/bjnano.8.261] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 11/17/2017] [Indexed: 06/07/2023]
Abstract
Diarylethene-derived molecules alter their electronic structure upon transformation between the open and closed forms of the diarylethene core, when exposed to ultraviolet (UV) or visible light. This transformation results in a significant variation of electrical conductance and vibrational properties of corresponding molecular junctions. We report here a combined experimental and theoretical analysis of charge transport through diarylethene-derived single-molecule devices, which are created using the mechanically controlled break-junction technique. Inelastic electron tunneling (IET) spectroscopy measurements performed at 4.2 K are compared with first-principles calculations in the two distinct forms of diarylethenes connected to gold electrodes. The combined approach clearly demonstrates that the IET spectra of single-molecule junctions show specific vibrational features that can be used to identify different isomeric molecular states by transport experiments.
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Affiliation(s)
- Youngsang Kim
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Lam Research, Fremont, California 94538, United States
| | - Safa G Bahoosh
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
| | - Dmytro Sysoiev
- Department of Chemistry, University of Konstanz, 78457 Konstanz, Germany
| | - Thomas Huhn
- Department of Chemistry, University of Konstanz, 78457 Konstanz, Germany
| | - Fabian Pauly
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
- Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0395, Japan
| | - Elke Scheer
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
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19
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Nachman N, Selzer Y. Thermometry of Plasmonic Heating by Inelastic Electron Tunneling Spectroscopy (IETS). NANO LETTERS 2017; 17:5855-5861. [PMID: 28834435 DOI: 10.1021/acs.nanolett.7b03153] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The electronic and lattice heating accompanying plasmonic structures under illumination is suggested to be utilized in a broad range of thermoplasmonic applications. Specifically, in molecular electronics precise determination of the temperature of illuminated junctions is crucial, because the temperature-dependent energy distribution of charge carriers in the leads affects the possibility to steer various light-controlled conductance processes. Existing optical methods to characterize the local temperature in all these applications lack the spatial resolution to probe the few nanometers in size hot spots and therefore typically report average values over a diffraction limited length scale. Here we demonstrate that inelastic electron tunneling spectroscopy of molecular junctions based on thiol-alkyl chains can be used to precisely measure the temperature of metal nanoscale gaps under illumination. The nature of this measurement guarantees that the reported temperature indeed characterizes the confined volume in which heat is produced by the relaxation of hot carriers. Using a simple model, we suggest that the accuracy of the method enables also one to semiquantify the energy distribution of the hot carriers.
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Affiliation(s)
- Nirit Nachman
- School of Chemistry, Tel Aviv University , Tel Aviv 69978, Israel
| | - Yoram Selzer
- School of Chemistry, Tel Aviv University , Tel Aviv 69978, Israel
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20
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Kim YH, Kim HS, Lee J, Tsutsui M, Kawai T. Stretching-Induced Conductance Variations as Fingerprints of Contact Configurations in Single-Molecule Junctions. J Am Chem Soc 2017; 139:8286-8294. [PMID: 28537729 DOI: 10.1021/jacs.7b03393] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Molecule-electrode contact atomic structures are a critical factor that characterizes molecular devices, but their precise understanding and control still remain elusive. Based on combined first-principles calculations and single-molecule break junction experiments, we herein establish that the conductance of alkanedithiolate junctions can both increase and decrease with mechanical stretching, and the specific trend is determined by the S-Au linkage coordination number (CN) or the molecule-electrode contact atomic structure. Specifically, we find that the mechanical pulling results in the conductance increase for the junctions based on S-Au CN two and CN three contacts, while the conductance is minimally affected by stretching for junctions with the CN one contact and decreases upon the formation of Au monatomic chains. Detailed analysis unravels the mechanisms involving the competition between the stretching-induced upshift of the highest occupied molecular orbital-related states toward the Fermi level of electrodes and the deterioration of molecule-electrode electronic couplings in different contact CN cases. Moreover, we experimentally find a higher chance to observe the conductance enhancement mode under a faster elongation speed, which is explained by ab initio molecular dynamics simulations that reveal an important role of thermal fluctuations in aiding deformations of contacts into low-coordination configurations that include monatomic Au chains. Pointing out the insufficiency in previous notions of associating peak values in conductance histograms with specific contact atomic structures, this work resolves the controversy on the origins of ubiquitous multiple conductance peaks in S-Au-based single-molecule junctions.
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Affiliation(s)
- Yong-Hoon Kim
- Graduate School of Energy, Environment, Water, and Sustainability, Korea Advanced Institute of Science and Technology , 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Korea
| | - Hu Sung Kim
- Graduate School of Energy, Environment, Water, and Sustainability, Korea Advanced Institute of Science and Technology , 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Korea
| | - Juho Lee
- Graduate School of Energy, Environment, Water, and Sustainability, Korea Advanced Institute of Science and Technology , 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Korea
| | - Makusu Tsutsui
- The Institute of Scientific and Industrial Research, Osaka University , 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
| | - Tomoji Kawai
- The Institute of Scientific and Industrial Research, Osaka University , 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
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21
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Magyarkuti A, Lauritzen KP, Balogh Z, Nyáry A, Mészáros G, Makk P, Solomon GC, Halbritter A. Temporal correlations and structural memory effects in break junction measurements. J Chem Phys 2017. [DOI: 10.1063/1.4975180] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- A. Magyarkuti
- Department of Physics, Budapest University of Technology and Economics, MTA-BME Condensed Matter Research Group, Budafoki ut 8, 1111 Budapest, Hungary
| | - K. P. Lauritzen
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Z. Balogh
- Department of Physics, Budapest University of Technology and Economics, MTA-BME Condensed Matter Research Group, Budafoki ut 8, 1111 Budapest, Hungary
| | - A. Nyáry
- Department of Physics, Budapest University of Technology and Economics, MTA-BME Condensed Matter Research Group, Budafoki ut 8, 1111 Budapest, Hungary
| | - G. Mészáros
- Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar Tudósok Körútja 2, H-1117 Budapest, Hungary
| | - P. Makk
- Department of Physics, Budapest University of Technology and Economics, MTA-BME Condensed Matter Research Group, Budafoki ut 8, 1111 Budapest, Hungary
| | - G. C. Solomon
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - A. Halbritter
- Department of Physics, Budapest University of Technology and Economics, MTA-BME Condensed Matter Research Group, Budafoki ut 8, 1111 Budapest, Hungary
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22
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Bock S, Al‐Owaedi OA, Eaves SG, Milan DC, Lemmer M, Skelton BW, Osorio HM, Nichols RJ, Higgins SJ, Cea P, Long NJ, Albrecht T, Martín S, Lambert CJ, Low PJ. Single-Molecule Conductance Studies of Organometallic Complexes Bearing 3-Thienyl Contacting Groups. Chemistry 2017; 23:2133-2143. [PMID: 27897344 PMCID: PMC5396322 DOI: 10.1002/chem.201604565] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Indexed: 01/09/2023]
Abstract
The compounds and complexes 1,4-C6 H4 (C≡C-cyclo-3-C4 H3 S)2 (2), trans-[Pt(C≡C-cyclo-3-C4 H3 S)2 (PEt3 )2 ] (3), trans-[Ru(C≡C-cyclo-3-C4 H3 S)2 (dppe)2 ] (4; dppe=1,2-bis(diphenylphosphino)ethane) and trans-[Ru(C≡C-cyclo-3-C4 H3 S)2 {P(OEt)3 }4 ] (5) featuring the 3-thienyl moiety as a surface contacting group for gold electrodes have been prepared, crystallographically characterised in the case of 3-5 and studied in metal|molecule|metal junctions by using both scanning tunnelling microscope break-junction (STM-BJ) and STM-I(s) methods (measuring the tunnelling current (I) as a function of distance (s)). The compounds exhibit similar conductance profiles, with a low conductance feature being more readily identified by STM-I(s) methods, and a higher feature by the STM-BJ method. The lower conductance feature was further characterised by analysis using an unsupervised, automated multi-parameter vector classification (MPVC) of the conductance traces. The combination of similarly structured HOMOs and non-resonant tunnelling mechanism accounts for the remarkably similar conductance values across the chemically distinct members of the family 2-5.
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Affiliation(s)
- Sören Bock
- School of Chemistry and BiochemistryUniversity of Western Australia35 Stirling HighwayCrawley6009WAAustralia
| | - Oday A. Al‐Owaedi
- Department of PhysicsLancaster UniversityLancasterLA1 4YBUK
- Department of Laser Physics, Women Faculty of ScienceBabylon UniversityIraq
| | - Samantha G. Eaves
- School of Chemistry and BiochemistryUniversity of Western Australia35 Stirling HighwayCrawley6009WAAustralia
- Department of ChemistryDurham UniversitySouth Rd.DurhamDH1 3LEUK
| | - David C. Milan
- Department of ChemistryUniversity of LiverpoolCrown St.LiverpoolL69 7ZDUK
| | - Mario Lemmer
- Department of ChemistryImperial College LondonLondonSW7 2AZUK
| | - Brian W. Skelton
- School of Chemistry and BiochemistryUniversity of Western Australia35 Stirling HighwayCrawley6009WAAustralia
- Centre for Microscopy, Characterisation and AnalysisUniversity of Western AustraliaCrawleyWestern Australia6009Australia
| | - Henrry M. Osorio
- Departamento de Química Física, Facultad de CienciasUniversidad de Zaragoza50009ZaragozaSpain
- Instituto de Nanociencia de Aragón (INA) y Laboratorio de Microscopias, Avanzadas (LMA), Edificio I+D Campus Rio EbroUniversidad de ZaragozaC/Mariano Esquillor, s/n50018ZaragozaSpain
- Departamento de FísicaEscuela Politécnica NacionalAv. Ladrón de Guevara, E11-253170525QuitoEcuador
| | - Richard J. Nichols
- Department of ChemistryUniversity of LiverpoolCrown St.LiverpoolL69 7ZDUK
| | - Simon J. Higgins
- Department of ChemistryUniversity of LiverpoolCrown St.LiverpoolL69 7ZDUK
| | - Pilar Cea
- Departamento de Química Física, Facultad de CienciasUniversidad de Zaragoza50009ZaragozaSpain
- Instituto de Nanociencia de Aragón (INA) y Laboratorio de Microscopias, Avanzadas (LMA), Edificio I+D Campus Rio EbroUniversidad de ZaragozaC/Mariano Esquillor, s/n50018ZaragozaSpain
| | | | - Tim Albrecht
- Department of ChemistryImperial College LondonLondonSW7 2AZUK
| | - Santiago Martín
- Departamento de Química Física, Facultad de CienciasUniversidad de Zaragoza50009ZaragozaSpain
- Instituto de Ciencias de Materiales de Aragón (ICMA)Universidad de Zaragoza-CSIC50009ZaragozaSpain
| | | | - Paul J. Low
- School of Chemistry and BiochemistryUniversity of Western Australia35 Stirling HighwayCrawley6009WAAustralia
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23
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Xie Z, Bâldea I, Oram S, Smith CE, Frisbie CD. Effect of Heteroatom Substitution on Transport in Alkanedithiol-Based Molecular Tunnel Junctions: Evidence for Universal Behavior. ACS NANO 2017; 11:569-578. [PMID: 27936325 DOI: 10.1021/acsnano.6b06623] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The transport properties of molecular junctions based on alkanedithiols with three different methylene chain lengths were compared with junctions based on similar chains wherein every third -CH2- was replaced with O or S, that is, following the general formula HS(CH2CH2X)nCH2CH2SH, where X = CH2, O, or S and n = 1, 2, or 3. Conducting probe atomic force microscopy revealed that the low bias resistance of the chains increased upon substitution in the order CH2 < O < S. This change in resistance is ascribed to the observed identical trend in contact resistance, Rc, whereas the exponential prefactor β (length sensitivity) was essentially the same for all chains. Using an established, analytical single-level model, we computed the effective energy offset εh (i.e., Fermi level relative to the effective HOMO level) and the electronic coupling strength Γ from the current-voltage (I-V) data. The εh values were only weakly affected by heteroatom substitution, whereas the interface coupling strength Γ varied by over an order of magnitude. Consequently, we ascribe the strong variation in Rc to the systematic change in Γ. Quantum chemical calculations reveal that the HOMO density shifts from the terminal SH groups for the alkanedithiols to the heteroatoms in the substituted chains, which provides a plausible explanation for the marked decrease in Γ for the dithiols with electron-rich heteroatoms. The results indicate that the electronic coupling and thus the resistance of alkanedithiols can be tuned by substitution of even a single atom in the middle of the molecule. Importantly, when appropriately normalized, the experimental I-V curves were accurately simulated over the full bias range (±1.5 V) using the single-level model with no adjustable parameters. The data could be collapsed to a single universal curve predicted by the model, providing clear evidence that the essential physics is captured by this analytical approach and supporting its utility for molecular electronics.
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Affiliation(s)
- Zuoti Xie
- Department of Chemical Engineering and Materials Science and Department of Chemistry, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Ioan Bâldea
- Theoretische Chemie, Universität Heidelberg , INF 229, D-69120 Heidelberg, Germany
- National Institute of Lasers, Plasma and Radiation Physics, Institute of Space Science , POB MG-23, RO 077125 Bucharest, Romania
| | - Stuart Oram
- Department of Chemical Engineering and Materials Science and Department of Chemistry, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Christopher E Smith
- Department of Chemical Engineering and Materials Science and Department of Chemistry, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - C Daniel Frisbie
- Department of Chemical Engineering and Materials Science and Department of Chemistry, University of Minnesota , Minneapolis, Minnesota 55455, United States
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24
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Kim E, Baaske MD, Vollmer F. In Situ Observation of Single-Molecule Surface Reactions from Low to High Affinities. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2016; 28:9941-9948. [PMID: 27677787 DOI: 10.1002/adma.201603153] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 08/03/2016] [Indexed: 05/11/2023]
Abstract
In situ observation of single-molecule surface reactions from low to high affinities is achieved by resonant coupling between optical whispering-gallery modes and the localized surface plasmon of nanorods. Transient and permanent interactions between ligands (thiol, amine) and the gold surface are monitored without labels, allowing direct determination of the associated kinetic constants and rapid development of new functionalization protocols.
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Affiliation(s)
- Eugene Kim
- Max Planck Institute for the Science of Light, Günther-Scharowsky-Straβe 1, 91058, Erlangen, Germany
| | - Martin D Baaske
- Max Planck Institute for the Science of Light, Günther-Scharowsky-Straβe 1, 91058, Erlangen, Germany
| | - Frank Vollmer
- Max Planck Institute for the Science of Light, Günther-Scharowsky-Straβe 1, 91058, Erlangen, Germany
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25
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Kanthasamy K, Ring M, Nettelroth D, Tegenkamp C, Butenschön H, Pauly F, Pfnür H. Charge Transport through Ferrocene 1,1'-Diamine Single-Molecule Junctions. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2016; 12:4849-4856. [PMID: 27432721 DOI: 10.1002/smll.201601051] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Revised: 06/12/2016] [Indexed: 06/06/2023]
Abstract
The charge transport through ferrocene 1,1'-diamine (FDA) molecules between gold electrodes is investigated using the mechanically controllable break junction technique combined with a theoretical framework of density functional theory simulations to understand the physics of these molecular junctions. The characteristic conductances of the molecule are measured at low bias as well as current-voltage (IV) characteristics. By fitting the IV characteristics to the single-level model, the values for the position of the molecular level, mainly responsible for the transport, and its coupling to the leads, are obtained. The influence of the binding sites, molecular conformation, and electrode distance are systematically studied from a theoretical perspective. While a strong dependence of conductance on the adsorption geometry is found, the decrease of conductance as a function of electrode distance arises mainly from a decrease of coupling strength of the molecular electronic orbitals through a reduced overlap and, to a lesser extent, from a shift of their alignment with respect to the Fermi energy.
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Affiliation(s)
- Karthiga Kanthasamy
- Institut für Festkörperphysik, ATMOS, Appelstr. 2, D-30167, Hannover, Germany
| | - Markus Ring
- Fachbereich Physik, Universitätsstr. 10, D-78464, Konstanz, Germany
| | - Dennes Nettelroth
- Institut für Organische Chemie, Leibniz Universität Hannover, Schneiderberg 1B, D-30167, Hannover, Germany
| | - Christoph Tegenkamp
- Institut für Festkörperphysik, ATMOS, Appelstr. 2, D-30167, Hannover, Germany
- Laboratorium für Nano- und Quantenengineering, Schneiderberg 30, D-30167, Hannover, Germany
| | - Holger Butenschön
- Institut für Organische Chemie, Leibniz Universität Hannover, Schneiderberg 1B, D-30167, Hannover, Germany
| | - Fabian Pauly
- Fachbereich Physik, Universitätsstr. 10, D-78464, Konstanz, Germany
| | - Herbert Pfnür
- Institut für Festkörperphysik, ATMOS, Appelstr. 2, D-30167, Hannover, Germany.
- Laboratorium für Nano- und Quantenengineering, Schneiderberg 30, D-30167, Hannover, Germany.
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26
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Hayakawa R, Karimi MA, Wolf J, Huhn T, Zöllner MS, Herrmann C, Scheer E. Large Magnetoresistance in Single-Radical Molecular Junctions. NANO LETTERS 2016; 16:4960-4967. [PMID: 27458666 DOI: 10.1021/acs.nanolett.6b01595] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Organic radicals are promising building blocks for molecular spintronics. Little is known about the role of unpaired electrons for electron transport at the single-molecule level. Here, we examine the impact of magnetic fields on electron transport in single oligo(p-phenyleneethynylene) (OPE)-based radical molecular junctions, which are formed with a mechanically controllable break-junction technique at a low temperature of 4.2 K. Surprisingly huge positive magnetoresistances (MRs) of 16 to 287% are visible for a magnetic field of 4 T, and the values are at least 1 order of magnitude larger than those of the analogous pristine OPE (2-4%). Rigorous analysis of the MR and of current-voltage and inelastic electron-tunneling spectroscopy measurements reveal an effective reduction of the electronic coupling between the current-carrying molecular orbital and the electrodes with increasing magnetic field. We suggest that the large MR for the single-radical molecular junctions might be ascribed to a loss of phase coherence of the charge carriers induced by the magnetic field. Although further investigations are required to reveal the mechanism underlying the strong MR, our findings provide a potential approach for tuning charge transport in metal-molecule junctions with organic radicals.
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Affiliation(s)
- Ryoma Hayakawa
- International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science , 1-1 Namiki, Tsukuba 305-0044, Japan
| | | | | | | | - Martin Sebastian Zöllner
- Institute for Inorganic and Applied Chemistry, University of Hamburg , Martin-Luther-King-Platz 6, 20146 Hamburg, Germany
| | - Carmen Herrmann
- Institute for Inorganic and Applied Chemistry, University of Hamburg , Martin-Luther-King-Platz 6, 20146 Hamburg, Germany
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27
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Karimi MA, Bahoosh SG, Valášek M, Bürkle M, Mayor M, Pauly F, Scheer E. Identification of the current path for a conductive molecular wire on a tripodal platform. NANOSCALE 2016; 8:10582-10590. [PMID: 27163116 DOI: 10.1039/c5nr08708b] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We present the chemical synthesis as well as charge transport measurements and calculations for a new tripodal platform based on a rigid 9,9'-spirobifluorene equipped with a phenylene-ethynylene wire. The transport experiments are performed with the help of the low-temperature mechanically controlled break junction technique with gold electrodes. By combining experimental and theoretical investigations of elastic and inelastic charge transport, we show that the current proceeds through the designated molecular wire and identify a binding geometry that is compatible with the experimental observations. The conductive molecular wire on the platform features a well-defined and relatively high conductance of the order of 10(-3)G0 despite the length of the current path of more than 1.7 nm, demonstrating that this platform is suitable to incorporate functional units like molecular switches or sensors.
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Affiliation(s)
- M A Karimi
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany.
| | - S G Bahoosh
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany.
| | - M Valášek
- Karlsruhe Institute of Technology (KIT), Institute of Nanotechnology, P.O. Box 3640, 76021 Karlsruhe, Germany
| | - M Bürkle
- Nanosystem Research Institute (NRI) 'RICS', National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568, Japan
| | - M Mayor
- Karlsruhe Institute of Technology (KIT), Institute of Nanotechnology, P.O. Box 3640, 76021 Karlsruhe, Germany and Department of Chemistry, University of Basel, 4056 Basel, Switzerland and Lehn Institute of Functional Materials (LIFM), Sun Yat-Sen University (SYSU), Xingang Rd. W., Guangzhou, China
| | - F Pauly
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany.
| | - E Scheer
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany.
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28
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Xiang D, Wang X, Jia C, Lee T, Guo X. Molecular-Scale Electronics: From Concept to Function. Chem Rev 2016; 116:4318-440. [DOI: 10.1021/acs.chemrev.5b00680] [Citation(s) in RCA: 816] [Impact Index Per Article: 102.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Dong Xiang
- Beijing
National Laboratory for Molecular Sciences, State Key Laboratory for
Structural Chemistry of Unstable and Stable Species, College of Chemistry
and Molecular Engineering, Peking University, Beijing 100871, China
- Key
Laboratory of Optical Information Science and Technology, Institute
of Modern Optics, College of Electronic Information and Optical Engineering, Nankai University, Tianjin 300071, China
| | - Xiaolong Wang
- Beijing
National Laboratory for Molecular Sciences, State Key Laboratory for
Structural Chemistry of Unstable and Stable Species, College of Chemistry
and Molecular Engineering, Peking University, Beijing 100871, China
| | - Chuancheng Jia
- Beijing
National Laboratory for Molecular Sciences, State Key Laboratory for
Structural Chemistry of Unstable and Stable Species, College of Chemistry
and Molecular Engineering, Peking University, Beijing 100871, China
| | - Takhee Lee
- Department
of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul 08826, Korea
| | - Xuefeng Guo
- Beijing
National Laboratory for Molecular Sciences, State Key Laboratory for
Structural Chemistry of Unstable and Stable Species, College of Chemistry
and Molecular Engineering, Peking University, Beijing 100871, China
- Department
of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China
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29
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Hybertsen MS, Venkataraman L. Structure-Property Relationships in Atomic-Scale Junctions: Histograms and Beyond. Acc Chem Res 2016; 49:452-60. [PMID: 26938931 DOI: 10.1021/acs.accounts.6b00004] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Over the past 10 years, there has been tremendous progress in the measurement, modeling and understanding of structure-function relationships in single molecule junctions. Numerous research groups have addressed significant scientific questions, directed both to conductance phenomena at the single molecule level and to the fundamental chemistry that controls junction functionality. Many different functionalities have been demonstrated, including single-molecule diodes, optically and mechanically activated switches, and, significantly, physical phenomena with no classical analogues, such as those based on quantum interference effects. Experimental techniques for reliable and reproducible single molecule junction formation and characterization have led to this progress. In particular, the scanning tunneling microscope based break-junction (STM-BJ) technique has enabled rapid, sequential measurement of large numbers of nanoscale junctions allowing a statistical analysis to readily distinguish reproducible characteristics. Harnessing fundamental link chemistry has provided the necessary chemical control over junction formation, enabling measurements that revealed clear relationships between molecular structure and conductance characteristics. Such link groups (amines, methylsuflides, pyridines, etc.) maintain a stable lone pair configuration that selectively bonds to specific, undercoordinated transition metal atoms available following rupture of a metal point contact in the STM-BJ experiments. This basic chemical principle rationalizes the observation of highly reproducible conductance signatures. Subsequently, the method has been extended to probe a variety of physical phenomena ranging from basic I-V characteristics to more complex properties such as thermopower and electrochemical response. By adapting the technique to a conducting cantilever atomic force microscope (AFM-BJ), simultaneous measurement of the mechanical characteristics of nanoscale junctions as they are pulled apart has given complementary information such as the stiffness and rupture force of the molecule-metal link bond. Overall, while the BJ technique does not produce a single molecule circuit for practical applications, it has proved remarkably versatile for fundamental studies. Measured data and analysis have been combined with atomic-scale theory and calculations, typically performed for representative junction structures, to provide fundamental physical understanding of structure-function relationships. This Account integrates across an extensive series of our specific nanoscale junction studies which were carried out with the STM- and AFM-BJ techniques and supported by theoretical analysis and density functional theory based calculations, with emphasis on the physical characteristics of the measurement process and the rich data sets that emerge. Several examples illustrate the impact of measured trends based on the most probable values for key characteristics (obtained from ensembles of order 1000-10 000 individual junctions) to build a solid picture of conductance phenomena as well as attributes of the link bond chemistry. The key forward-looking question posed here is the extent to which the full data sets represented by the individual trajectories can be analyzed to address structure-function questions at the level of individual junctions. Initial progress toward physical modeling of conductance of individual junctions indicates trends consistent with physical junction structures. Analysis of junction mechanics reveals a scaling procedure that collapses existing data onto a universal force-extension curve. This research directed to understanding the distribution of structures and physical characteristics addresses fundamental questions concerning the interplay between chemical control and stochastically driven diversity.
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Affiliation(s)
- Mark S. Hybertsen
- Center
for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Latha Venkataraman
- Department
of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United States
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30
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Karimi MA, Bahoosh SG, Herz M, Hayakawa R, Pauly F, Scheer E. Shot Noise of 1,4-Benzenedithiol Single-Molecule Junctions. NANO LETTERS 2016; 16:1803-1807. [PMID: 26859711 DOI: 10.1021/acs.nanolett.5b04848] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We report measurements of the shot noise on single-molecule Au-1,4-benzenedithiol-Au junctions, fabricated with the mechanically controllable break junction (MCBJ) technique at 4.2 K in a wide range of conductance values from 10(-2) to 0.24 conductance quanta. We introduce a simple measurement scheme using a current amplifier and a spectrum analyzer and that does not imply special requirements regarding the electrical leads. The experimental findings provide evidence that the current is carried by a single conduction channel throughout the whole conductance range. This observation suggests that the number of channels is limited by the Au-thiol bonds and that contributions due to direct tunneling from the Au to the π-system of the aromatic ring are negligible also for high conductance. The results are supported by quantum transport calculations using density functional theory.
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Affiliation(s)
- M A Karimi
- Department of Physics, University of Konstanz , 78457 Konstanz, Germany
| | - S G Bahoosh
- Department of Physics, University of Konstanz , 78457 Konstanz, Germany
| | - M Herz
- Department of Physics, University of Konstanz , 78457 Konstanz, Germany
| | - R Hayakawa
- Department of Physics, University of Konstanz , 78457 Konstanz, Germany
- International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science , 1-1 Namiki, Tsukuba 305-0044, Japan
| | - F Pauly
- Department of Physics, University of Konstanz , 78457 Konstanz, Germany
| | - E Scheer
- Department of Physics, University of Konstanz , 78457 Konstanz, Germany
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31
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Xiang A, Wang M, Wang H, Sun H, Hou S, Liao J. The origin of the transition voltage of gold–alkanedithiol–gold molecular junctions. Chem Phys 2016. [DOI: 10.1016/j.chemphys.2015.11.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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32
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Villagómez CJ, Castanié F, Momblona C, Gauthier S, Zambelli T, Bouju X. Adsorption of single 1,8-octanedithiol molecules on Cu(100). Phys Chem Chem Phys 2016; 18:27521-27528. [DOI: 10.1039/c6cp04449b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
STM experiments and calculations have allowed identifying the most favorable conformation of a single octanedithiol molecule on a copper surface.
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Affiliation(s)
- Carlos J. Villagómez
- Instituto de Física
- Universidad Nacional Autónoma de México
- Mexico
- CEMES-CNRS
- 31055 Toulouse Cedex 4
| | - Fabien Castanié
- CEMES-CNRS
- 31055 Toulouse Cedex 4
- France
- Université de Toulouse
- UPS
| | - Cristina Momblona
- CEMES-CNRS
- 31055 Toulouse Cedex 4
- France
- Instituto de Nanociencia de Aragoń (INA)
- Edificio i+d
| | | | - Tomaso Zambelli
- CEMES-CNRS
- 31055 Toulouse Cedex 4
- France
- Swiss Fed. Inst. Technlo
- Inst. Biomed. Engn
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33
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Yu X, Lovrincic R, Sepunaru L, Li W, Vilan A, Pecht I, Sheves M, Cahen D. Insights into Solid-State Electron Transport through Proteins from Inelastic Tunneling Spectroscopy: The Case of Azurin. ACS NANO 2015; 9:9955-63. [PMID: 26381112 DOI: 10.1021/acsnano.5b03950] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Surprisingly efficient solid-state electron transport has recently been demonstrated through "dry" proteins (with only structural, tightly bound H2O left), suggesting proteins as promising candidates for molecular (bio)electronics. Using inelastic electron tunneling spectroscopy (IETS), we explored electron-phonon interaction in metal/protein/metal junctions, to help understand solid-state electronic transport across the redox protein azurin. To that end an oriented azurin monolayer on Au is contacted by soft Au electrodes. Characteristic vibrational modes of amide and amino acid side groups as well as of the azurin-electrode contact were observed, revealing the azurin native conformation in the junction and the critical role of side groups in the charge transport. The lack of abrupt changes in the conductance and the line shape of IETS point to far off-resonance tunneling as the dominant transport mechanism across azurin, in line with previously reported (and herein confirmed) azurin junctions. The inelastic current and hence electron-phonon interaction appear to be rather weak and comparable in magnitude with the inelastic fraction of tunneling current via alkyl chains, which may reflect the known structural rigidity of azurin.
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Affiliation(s)
| | - Robert Lovrincic
- Institute for High Frequency Technology, TU Braunschweig, and Innovationlab , Speyerer Str. 4, 69115 Heidelberg, Germany
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34
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Sepunaru L, Refaely-Abramson S, Lovrinčić R, Gavrilov Y, Agrawal P, Levy Y, Kronik L, Pecht I, Sheves M, Cahen D. Electronic Transport via Homopeptides: The Role of Side Chains and Secondary Structure. J Am Chem Soc 2015; 137:9617-26. [DOI: 10.1021/jacs.5b03933] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Lior Sepunaru
- Department of Materials and Interfaces, ‡Department of Organic
Chemistry, §Department of Structural
Biology, and ∥Department of Immunology, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Sivan Refaely-Abramson
- Department of Materials and Interfaces, ‡Department of Organic
Chemistry, §Department of Structural
Biology, and ∥Department of Immunology, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Robert Lovrinčić
- Department of Materials and Interfaces, ‡Department of Organic
Chemistry, §Department of Structural
Biology, and ∥Department of Immunology, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Yulian Gavrilov
- Department of Materials and Interfaces, ‡Department of Organic
Chemistry, §Department of Structural
Biology, and ∥Department of Immunology, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Piyush Agrawal
- Department of Materials and Interfaces, ‡Department of Organic
Chemistry, §Department of Structural
Biology, and ∥Department of Immunology, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Yaakov Levy
- Department of Materials and Interfaces, ‡Department of Organic
Chemistry, §Department of Structural
Biology, and ∥Department of Immunology, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Leeor Kronik
- Department of Materials and Interfaces, ‡Department of Organic
Chemistry, §Department of Structural
Biology, and ∥Department of Immunology, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Israel Pecht
- Department of Materials and Interfaces, ‡Department of Organic
Chemistry, §Department of Structural
Biology, and ∥Department of Immunology, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Mordechai Sheves
- Department of Materials and Interfaces, ‡Department of Organic
Chemistry, §Department of Structural
Biology, and ∥Department of Immunology, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - David Cahen
- Department of Materials and Interfaces, ‡Department of Organic
Chemistry, §Department of Structural
Biology, and ∥Department of Immunology, Weizmann Institute of Science, Rehovot, 7610001, Israel
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35
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Li H, Su TA, Zhang V, Steigerwald ML, Nuckolls C, Venkataraman L. Electric Field Breakdown in Single Molecule Junctions. J Am Chem Soc 2015; 137:5028-33. [DOI: 10.1021/ja512523r] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Haixing Li
- Department
of Applied Physics and Applied Mathematics and ‡Department of
Chemistry, Columbia University, New York, New York 10027, United States
| | - Timothy A. Su
- Department
of Applied Physics and Applied Mathematics and ‡Department of
Chemistry, Columbia University, New York, New York 10027, United States
| | - Vivian Zhang
- Department
of Applied Physics and Applied Mathematics and ‡Department of
Chemistry, Columbia University, New York, New York 10027, United States
| | - Michael L. Steigerwald
- Department
of Applied Physics and Applied Mathematics and ‡Department of
Chemistry, Columbia University, New York, New York 10027, United States
| | - Colin Nuckolls
- Department
of Applied Physics and Applied Mathematics and ‡Department of
Chemistry, Columbia University, New York, New York 10027, United States
| | - Latha Venkataraman
- Department
of Applied Physics and Applied Mathematics and ‡Department of
Chemistry, Columbia University, New York, New York 10027, United States
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36
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Leary E, La Rosa A, González MT, Rubio-Bollinger G, Agraït N, Martín N. Incorporating single molecules into electrical circuits. The role of the chemical anchoring group. Chem Soc Rev 2015; 44:920-42. [DOI: 10.1039/c4cs00264d] [Citation(s) in RCA: 134] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Constructing electronic circuits containing singly wired molecules is at the frontier of electrical device miniaturisation. Understanding the behaviour of different anchoring groups is key to this goal because of their significant role in determining the properties of the junction.
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Affiliation(s)
- Edmund Leary
- IMDEA Nanociencia
- C/Faraday 9
- 28049 Madrid
- Spain
- Depto. Física de la Materia Condensada Mod. 3-610 – Universidad Autónoma de Madrid
| | - Andrea La Rosa
- Departamento de Química Orgánica
- Facultad de Ciencias Quıímicas
- Universidad Complutense de Madrid
- Madrid
- Spain
| | | | - Gabino Rubio-Bollinger
- Depto. Física de la Materia Condensada Mod. 3-610 – Universidad Autónoma de Madrid
- 28049 Madrid
- Spain
| | - Nicolás Agraït
- IMDEA Nanociencia
- C/Faraday 9
- 28049 Madrid
- Spain
- Depto. Física de la Materia Condensada Mod. 3-610 – Universidad Autónoma de Madrid
| | - Nazario Martín
- IMDEA Nanociencia
- C/Faraday 9
- 28049 Madrid
- Spain
- Departamento de Química Orgánica
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37
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Arielly R, Vadai M, Kardash D, Noy G, Selzer Y. Real-Time Detection of Redox Events in Molecular Junctions. J Am Chem Soc 2014; 136:2674-80. [DOI: 10.1021/ja412668f] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Rani Arielly
- School
of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
| | - Michal Vadai
- School
of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
| | - Dina Kardash
- School
of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
| | - Gilad Noy
- School
of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
| | - Yoram Selzer
- School
of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
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38
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Huang MJ, Hsu LY, Fu MD, Chuang ST, Tien FW, Chen CH. Conductance of Tailored Molecular Segments: A Rudimentary Assessment by Landauer Formulation. J Am Chem Soc 2014; 136:1832-41. [DOI: 10.1021/ja4088538] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Min-Jie Huang
- Department of Chemistry and
Center for Emerging Material and Advanced Devices, National Taiwan University, Taipei, Taiwan 10617
| | - Liang-Yan Hsu
- Department of Chemistry and
Center for Emerging Material and Advanced Devices, National Taiwan University, Taipei, Taiwan 10617
| | - Ming-Dung Fu
- Department of Chemistry and
Center for Emerging Material and Advanced Devices, National Taiwan University, Taipei, Taiwan 10617
| | - Su-Ting Chuang
- Department of Chemistry and
Center for Emerging Material and Advanced Devices, National Taiwan University, Taipei, Taiwan 10617
| | - Fang-Wei Tien
- Department of Chemistry and
Center for Emerging Material and Advanced Devices, National Taiwan University, Taipei, Taiwan 10617
| | - Chun-hsien Chen
- Department of Chemistry and
Center for Emerging Material and Advanced Devices, National Taiwan University, Taipei, Taiwan 10617
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39
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Abstract
Understanding charge transport of single molecules or a small collection of molecules sandwiched between electrodes is of fundamental importance for molecular electronics. This requires the fabrication of reliable devices, which depend on several factors including the testbed architectures used, the molecule number and defect density being tested, and the nature of the molecule-electrode interface. On the basis of significant progresses achieved in both experiments and theory over the past decade, in this tutorial review, we focus on new insights into the influence of the nature of the molecule-electrode interface, the most critical issue hindering the development of reliable devices, on the conducting properties of molecules. We summarize the strategies developed for controlling the interfacial properties and how the coupling strength between the molecules and the electrodes modulates the device properties. These analyses should be valuable for deeply understanding the relationship between the contact interface and the charge transport mechanism, which is of crucial importance for the development of molecular electronics, organic electronics, nanoelectronics, and other interface-related optoelectronic devices.
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Affiliation(s)
- Chuancheng Jia
- Center for NanoChemistry, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, PR China
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40
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Sun L, Diaz-Fernandez YA, Gschneidtner TA, Westerlund F, Lara-Avila S, Moth-Poulsen K. Single-molecule electronics: from chemical design to functional devices. Chem Soc Rev 2014; 43:7378-411. [DOI: 10.1039/c4cs00143e] [Citation(s) in RCA: 361] [Impact Index Per Article: 36.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The use of single molecules in electronics represents the next limit of miniaturisation of electronic devices, which would enable to continue the trend of aggressive downscaling of silicon-based electronic devices.
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Affiliation(s)
- Lanlan Sun
- Department of Chemical and Biological Engineering
- Chalmers University of Technology
- , Sweden
| | - Yuri A. Diaz-Fernandez
- Department of Chemical and Biological Engineering
- Chalmers University of Technology
- , Sweden
| | - Tina A. Gschneidtner
- Department of Chemical and Biological Engineering
- Chalmers University of Technology
- , Sweden
| | - Fredrik Westerlund
- Department of Chemical and Biological Engineering
- Chalmers University of Technology
- , Sweden
| | - Samuel Lara-Avila
- Department of Micro and Nanotechnology
- MC2
- Chalmers University of Technology
- , Sweden
| | - Kasper Moth-Poulsen
- Department of Chemical and Biological Engineering
- Chalmers University of Technology
- , Sweden
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41
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Yelin T, Vardimon R, Kuritz N, Korytár R, Bagrets A, Evers F, Kronik L, Tal O. Atomically wired molecular junctions: connecting a single organic molecule by chains of metal atoms. NANO LETTERS 2013; 13:1956-1961. [PMID: 23517527 DOI: 10.1021/nl304702z] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Using a break junction technique, we find a clear signature for the formation of conducting hybrid junctions composed of a single organic molecule (benzene, naphthalene, or anthracene) connected to chains of platinum atoms. The hybrid junctions exhibit metallic-like conductance (~0.1-1G0), which is rather insensitive to further elongation by additional atoms. At low bias voltage the hybrid junctions can be elongated significantly beyond the length of the bare atomic chains. Ab initio calculations reveal that benzene based hybrid junctions have a significant binding energy and high structural flexibility that may contribute to the survival of the hybrid junction during the elongation process. The fabrication of hybrid junctions opens the way for combining the different properties of atomic chains and organic molecules to realize a new class of atomic scale interfaces.
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Affiliation(s)
- Tamar Yelin
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot, 76100 Israel
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42
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González MT, Díaz A, Leary E, García R, Herranz MÁ, Rubio-Bollinger G, Martín N, Agraït N. Stability of Single- and Few-Molecule Junctions of Conjugated Diamines. J Am Chem Soc 2013; 135:5420-6. [DOI: 10.1021/ja312392q] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- M. Teresa González
- Instituto Madrileño de
Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Ciudad Universitaria de Cantoblanco, E-28049 Madrid,
Spain
| | | | - Edmund Leary
- Instituto Madrileño de
Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Ciudad Universitaria de Cantoblanco, E-28049 Madrid,
Spain
| | - Raúl García
- Departamento de Química
Orgánica, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - M. Ángeles Herranz
- Departamento de Química
Orgánica, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | | | - Nazario Martín
- Instituto Madrileño de
Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Ciudad Universitaria de Cantoblanco, E-28049 Madrid,
Spain
- Departamento de Química
Orgánica, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Nicolás Agraït
- Instituto Madrileño de
Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Ciudad Universitaria de Cantoblanco, E-28049 Madrid,
Spain
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43
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Ballesteros LM, Martín S, Cortés J, Marqués-González S, Higgins SJ, Nichols RJ, Low PJ, Cea P. Controlling the Structural and Electrical Properties of Diacid Oligo(Phenylene Ethynylene) Langmuir-Blodgett Films. Chemistry 2013; 19:5352-63. [DOI: 10.1002/chem.201203261] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Revised: 12/23/2012] [Indexed: 11/10/2022]
Affiliation(s)
- Luz Marina Ballesteros
- Departamento de Química Física, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza 50009, Spain
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44
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Chen IWP, Tseng WH, Gu MW, Su LC, Hsu CH, Chang WH, Chen CH. Tactile-feedback stabilized molecular junctions for the measurement of molecular conductance. Angew Chem Int Ed Engl 2013; 52:2449-53. [PMID: 23341350 DOI: 10.1002/anie.201207116] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Revised: 12/05/2012] [Indexed: 11/08/2022]
Abstract
Handling the (AFM) tip: The duration of stable molecular junctions was prolonged using a tactile feedback method in which the operator can sense the force of the AFM tip on the sample surface. The movement of the tip is adjusted accordingly, maintaining a more consistent current (i) and voltage (V), instead of having the tip move at a constant preset speed, as in the conventional setup.
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Affiliation(s)
- I-Wen Peter Chen
- Department of Applied Science, National Taitung University, Taitung, Taiwan 95002, Taiwan
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45
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Chen IWP, Tseng WH, Gu MW, Su LC, Hsu CH, Chang WH, Chen CH. Tactile-Feedback Stabilized Molecular Junctions for the Measurement of Molecular Conductance. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201207116] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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46
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Burema SR, Bocquet ML. A sum rule for inelastic electron tunneling spectroscopy: an ab initio study of a donor (TTF) and acceptors (TCNE, TCNQ and DCNQI) parallelly oriented on Cu(100). Phys Chem Chem Phys 2013; 15:16111-9. [DOI: 10.1039/c3cp53049c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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47
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Gao Y, Aerts M, Sandeep CSS, Talgorn E, Savenije TJ, Kinge S, Siebbeles LDA, Houtepen AJ. Photoconductivity of PbSe quantum-dot solids: dependence on ligand anchor group and length. ACS NANO 2012; 6:9606-14. [PMID: 23078408 DOI: 10.1021/nn3029716] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The assembly of quantum dots is an essential step toward many of their potential applications. To form conductive solids from colloidal quantum dots, ligand exchange is required. Here we study the influence of ligand replacement on the photoconductivity of PbSe quantum-dot solids, using the time-resolved microwave conductivity technique. Bifunctional replacing ligands with amine, thiol, or carboxylic acid anchor groups of various lengths are used to assemble quantum solids via a layer-by-layer dip-coating method. We find that when the ligand lengths are the same, the charge carrier mobility is higher in quantum-dot solids with amine ligands, while in quantum-dot solids with thiol ligands the charge carrier lifetime is longer. If the anchor group is the same, the charge carrier mobility is ligand length dependent. The results show that the diffusion length of charge carriers can reach several hundred nanometers.
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Affiliation(s)
- Yunan Gao
- Optoelectronic Material Section, Department of Chemical Engineering, Delft University of Technology, Julianalaan 136, 2628 BL, Delft, The Netherlands
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48
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Briechle BM, Kim Y, Ehrenreich P, Erbe A, Sysoiev D, Huhn T, Groth U, Scheer E. Current-voltage characteristics of single-molecule diarylethene junctions measured with adjustable gold electrodes in solution. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2012; 3:798-808. [PMID: 23365792 PMCID: PMC3554105 DOI: 10.3762/bjnano.3.89] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2012] [Accepted: 11/12/2012] [Indexed: 06/01/2023]
Abstract
We report on an experimental analysis of the charge transport through sulfur-free photochromic molecular junctions. The conductance of individual molecules contacted with gold electrodes and the current-voltage characteristics of these junctions are measured in a mechanically controlled break-junction system at room temperature and in liquid environment. We compare the transport properties of a series of molecules, labeled TSC, MN, and 4Py, with the same switching core but varying side-arms and end-groups designed for providing the mechanical and electrical contact to the gold electrodes. We perform a detailed analysis of the transport properties of TSC in its open and closed states. We find rather broad distributions of conductance values in both states. The analysis, based on the assumption that the current is carried by a single dominating molecular orbital, reveals distinct differences between both states. We discuss the appearance of diode-like behavior for the particular species 4Py that features end-groups, which preferentially couple to the metal electrode by physisorption. We show that the energetic position of the molecular orbital varies as a function of the transmission. Finally, we show for the species MN that the use of two cyano end-groups on each side considerably enhances the coupling strength compared to the typical behavior of a single cyano group.
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Affiliation(s)
- Bernd M Briechle
- Physics Department, University of Konstanz, D-78457 Konstanz, Germany
| | - Youngsang Kim
- Physics Department, University of Konstanz, D-78457 Konstanz, Germany
| | | | - Artur Erbe
- Institute of Ion Beam Physics and Materials Research, Helmholtzzentrum Dresden-Rossendorf, D-01328 Dresden, Germany
| | - Dmytro Sysoiev
- Chemistry Department, University of Konstanz, D-78457 Konstanz, Germany
| | - Thomas Huhn
- Chemistry Department, University of Konstanz, D-78457 Konstanz, Germany
| | - Ulrich Groth
- Chemistry Department, University of Konstanz, D-78457 Konstanz, Germany
| | - Elke Scheer
- Physics Department, University of Konstanz, D-78457 Konstanz, Germany
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49
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Burema SR, Bocquet ML. Resonance Charges to Encode Selection Rules in Inelastic Electron Tunneling Spectroscopy. J Phys Chem Lett 2012; 3:3007-3011. [PMID: 26292242 DOI: 10.1021/jz3012832] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
From extensive simulations of a set of covalently grafted phenyl derivatives onto Cu(111), we derive a simplistic rule that selectively predicts the onset of stretching vibrations in inelastic electron tunneling spectroscopy (IETS) with the scanning tunneling microscope. Indeed the rise (extinction) of the highest-frequency modes is found to correlate to the accumulation (depletion) of π electron density at the metal-organic contact point. This π electron density can be fine-tuned by the usage of (de) activating aromatic substituent at different ring positions. This finding provides a simple analysis tool that can be used to reveal structural characteristics on the atomic scale by IETS.
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Affiliation(s)
- Shiri R Burema
- Ecole Normale Supérieure de Lyon, Laboratoire de Chimie, CNRS UMR 5182, 46 Allée d'Italie, 69364 CEDEX07 Lyon, France
| | - Marie-Laure Bocquet
- Ecole Normale Supérieure de Lyon, Laboratoire de Chimie, CNRS UMR 5182, 46 Allée d'Italie, 69364 CEDEX07 Lyon, France
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50
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Demir F, Kirczenow G. Inelastic tunneling spectroscopy of gold-thiol and gold-thiolate interfaces in molecular junctions: the role of hydrogen. J Chem Phys 2012; 137:094703. [PMID: 22957582 DOI: 10.1063/1.4748379] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
It is widely believed that when a molecule with thiol (S-H) end groups bridges a pair of gold electrodes, the S atoms bond to the gold and the thiol H atoms detach from the molecule. However, little is known regarding the details of this process, its time scale, and whether molecules with and without thiol hydrogen atoms can coexist in molecular junctions. Here, we explore theoretically how inelastic tunneling spectroscopy (IETS) can shed light on these issues. We present calculations of the geometries, low bias conductances, and IETS of propanedithiol and propanedithiolate molecular junctions with gold electrodes. We show that IETS can distinguish between junctions with molecules having no, one, or two thiol hydrogen atoms. We find that in most cases, the single-molecule junctions in the IETS experiment of Hihath et al. [Nano Lett. 8, 1673 (2008)] had no thiol H atoms, but that a molecule with a single thiol H atom may have bridged their junction occasionally. We also consider the evolution of the IETS spectrum as a gold STM tip approaches the intact S-H group at the end of a molecule bound at its other end to a second electrode. We predict the frequency of a vibrational mode of the thiol H atom to increase by a factor ~2 as the gap between the tip and molecule narrows. Therefore, IETS should be able to track the approach of the tip towards the thiol group of the molecule and detect the detachment of the thiol H atom from the molecule when it occurs.
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Affiliation(s)
- Firuz Demir
- Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada.
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