1
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Roemer M, Chen X, Li Y, Wang L, Yu X, Cazade PA, Nickle C, Akter R, Del Barco E, Thompson D, Nijhuis CA. Supramolecular tunnelling junctions with robust high rectification based on assembly effects. NANOSCALE 2024. [PMID: 39302153 DOI: 10.1039/d4nr01514b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/22/2024]
Abstract
The performance of large-area molecular diodes can in rare cases approach the lower limit of commercial semiconductor devices but predictive structure-property design remains difficult as the rectification ratio (R) achieved by self-assembled monolayer (SAM) based diodes depends on several intertwined parameters. This paper describes a systematic approach to achieve high rectification in bisferrocenyl-based molecular diodes, HSCnFc-CC-Fc (n = 9-15) immobilised on metal surfaces (Ag, Au and Pt). Experiments supported by molecular dynamics simulations show that the molecular length and bottom electrode influence the SAM packing, which affects the breakdown voltage (VBD), the associated maximum R (Rmax), and the bias at which the Rmax is achieved (Vsat,R). From the electrical characterisation of the most stable Pt-SCnFc-CC-Fc//GaOx/EGaIn junctions, we found that VBD, Vsat,R, and Rmax all scale linearly with the spacer length of Cn, and that Rmax for all the SAMs consistently exceeds the "Landauer limit" of 103. Our data shows that the robust switching of M-SCnFc-CC-Fc//GaOx/EGaIn junctions is the result of the combined optimisation of parameters involving the molecular structure, the type of metal substrate, and the applied operating conditions (bias window), to create stable and high-performance junctions.
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Affiliation(s)
- Max Roemer
- The University of Sydney, School of Chemistry, Sydney, NSW 2109, Australia
| | - Xiaoping Chen
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore.
- College of Chemistry, Chemical Engineering and Environment, Fujian Provincial Key Laboratory of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou, 363000, China
| | - Yuan Li
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore.
- Key Laboratory of Organic Optoelectronics, Department of Chemistry, Tsinghua University, Beijing, 100084, P.R. China
| | - Lejia Wang
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore.
| | - Xiaojiang Yu
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore 117603, Singapore
| | - Pierre-André Cazade
- Department of Physics, Bernal Institute, 34 University of Limerick, Limerick V94 T9PX, Ireland.
| | - Cameron Nickle
- University of Central Florida, Physics Department, Orlando, FL 32816, USA
| | - Romena Akter
- University of Central Florida, Physics Department, Orlando, FL 32816, USA
| | - Enrique Del Barco
- University of Central Florida, Physics Department, Orlando, FL 32816, USA
| | - Damien Thompson
- Department of Physics, Bernal Institute, 34 University of Limerick, Limerick V94 T9PX, Ireland.
| | - Christian A Nijhuis
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore.
- University of Twente, Faculty of Science and Technology (TNW), Hybrid Materials for Opto-Electronics (HMOE), 7500 AE, Enschede, The Netherlands
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2
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Chen L, Yang Z, Lin Q, Li X, Bai J, Hong W. Evolution of Single-Molecule Electronic Interfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:1988-2004. [PMID: 38227964 DOI: 10.1021/acs.langmuir.3c03104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
Single-molecule electronics can fabricate single-molecule devices via the construction of molecule-electrode interfaces and also provide a unique tool to investigate single-molecule scale physicochemical processes at these interfaces. To investigate single-molecule electronic devices with desired functionalities, an understanding of the interface evolution processes in single-molecule devices is essential. In this review, we focus on the evolution of molecule-electrode interface properties, including the background of interface evolution in single-molecule electronics, the construction of different types of single-molecule interfaces, and the regulation methods. Finally, we discuss the perspective of future characterization techniques and applications for single-molecule electronic interfaces.
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Affiliation(s)
- Lichuan Chen
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & College of Materials & IKKEM, Xiamen University, Xiamen 361000, China
| | - Zixian Yang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & College of Materials & IKKEM, Xiamen University, Xiamen 361000, China
| | - Qichao Lin
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & College of Materials & IKKEM, Xiamen University, Xiamen 361000, China
| | - Xiaohui Li
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & College of Materials & IKKEM, Xiamen University, Xiamen 361000, China
| | - Jie Bai
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & College of Materials & IKKEM, Xiamen University, Xiamen 361000, China
| | - Wenjing Hong
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering & College of Materials & IKKEM, Xiamen University, Xiamen 361000, China
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3
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Meng Q, Zhang J, Zhang Y, Chu W, Mao W, Zhang Y, Yang J, Luo Y, Dong Z, Hou JG. Local heating and Raman thermometry in a single molecule. SCIENCE ADVANCES 2024; 10:eadl1015. [PMID: 38232173 DOI: 10.1126/sciadv.adl1015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 12/15/2023] [Indexed: 01/19/2024]
Abstract
Because of the nonequilibrium nature of thermal effects at the nanoscale, the characterization of local thermal effects within a single molecule is highly challenging. Here, we demonstrate a way to characterize the local thermal properties of a single fullerene (C60) molecule during current-induced heating processes through tip-enhanced anti-Stokes Raman spectroscopy. Although the measured vibron populations are far from equilibrium with the environment, we can still define an "effective temperature (Teff)" statistically via a Bose-Einstein distribution, suggesting a local equilibrium within the molecule. With increased current heating, Teff is found to rise up to about 1150 K until the C60 cage is decomposed. Such a decomposition temperature is similar to that reported for ensemble C60 samples, thus justifying the validity of our methodology. Moreover, the possible reaction pathway and product can be identified because of the chemical sensitivity of Raman spectroscopy. Our findings provide a practical method for noninvasively detecting the local heating effect inside a single molecule under nonequilibrium conditions.
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Affiliation(s)
- Qiushi Meng
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
| | - Junxian Zhang
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Yao Zhang
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
- School of Physics and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Weizhe Chu
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Wenjie Mao
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Yang Zhang
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
- School of Physics and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Jinlong Yang
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
- School of Physics and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Yi Luo
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
- School of Physics and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Zhenchao Dong
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
- School of Physics and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - J G Hou
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
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4
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Chiang M, Lin Y, Zhao W, Liu H, Hsu R, Chou T, Lu T, Lee I, Liao L, Chiou S, Chu L, Hu S. In Situ Forming of Nitric Oxide and Electric Stimulus for Nerve Therapy by Wireless Chargeable Gold Yarn-Dynamos. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2303566. [PMID: 37867218 PMCID: PMC10667856 DOI: 10.1002/advs.202303566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 09/14/2023] [Indexed: 10/24/2023]
Abstract
Endogenous signals, namely nitric oxide (NO) and electrons, play a crucial role in regulating cell fate as well as the vascular and neuronal systems. Unfortunately, utilizing NO and electrical stimulation in clinical settings can be challenging due to NO's short half-life and the invasive electrodes required for electrical stimulation. Additionally, there is a lack of tools to spatiotemporally control gas release and electrical stimulation. To address these issues, an "electromagnetic messenger" approach that employs on-demand high-frequency magnetic field (HFMF) to trigger NO release and electrical stimulation for restoring brain function in cases of traumatic brain injury is introduced. The system comprises a NO donor (poly(S-nitrosoglutathione), pGSNO)-conjugated on a gold yarn-dynamos (GY) and embedded in an implantable silk in a microneedle. When subjected to HFMF, conductive GY induces eddy currents that stimulate the release of NO from pGSNO. This process significantly enhances neural stem cell (NSC) synapses' differentiation and growth. The combined strategy of using NO and electrical stimulation to inhibit inflammation, angiogenesis, and neuronal interrogation in traumatic brain injury is demonstrated in vivo.
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Affiliation(s)
- Min‐Ren Chiang
- Department of Biomedical Engineering and Environmental SciencesNational Tsing Hua UniversityHsinchu300044Taiwan
| | - Ya‐Hui Lin
- Department of Biomedical Engineering and Environmental SciencesNational Tsing Hua UniversityHsinchu300044Taiwan
- Brain Research CenterNational Tsing Hua UniversityHsinchu300044Taiwan
| | - Wei‐Jie Zhao
- Department of Biomedical Engineering and Environmental SciencesNational Tsing Hua UniversityHsinchu300044Taiwan
| | - Hsiu‐Ching Liu
- Department of Biomedical Engineering and Environmental SciencesNational Tsing Hua UniversityHsinchu300044Taiwan
| | - Ru‐Siou Hsu
- Department of ChemistryStanford UniversityStanfordCA94305USA
| | - Tsu‐Chin Chou
- Institute of Analytical and Environmental SciencesNational Tsing Hua UniversityHsinchu300044Taiwan
| | - Tsai‐Te Lu
- Institute of Biomedical EngineeringNational Tsing Hua UniversityHsinchu300044Taiwan
- Department of ChemistryNational Tsing Hua UniversityHsinchu300044Taiwan
- Department of ChemistryChung Yuan Christian UniversityTaoyuan320314Taiwan
| | - I‐Chi Lee
- Department of Biomedical Engineering and Environmental SciencesNational Tsing Hua UniversityHsinchu300044Taiwan
| | - Lun‐De Liao
- Institute of Biomedical Engineering and NanomedicineNational Health Research InstitutesMiaoli County35053Taiwan
| | - Shih‐Hwa Chiou
- Institute of PharmacologyCollege of MedicineNational Yang Ming Chiao Tung UniversityTaipei112304Taiwan
- Department of Medical ResearchTaipei Veterans General HospitalTaipei112201Taiwan
| | - Li‐An Chu
- Department of Biomedical Engineering and Environmental SciencesNational Tsing Hua UniversityHsinchu300044Taiwan
- Brain Research CenterNational Tsing Hua UniversityHsinchu300044Taiwan
| | - Shang‐Hsiu Hu
- Department of Biomedical Engineering and Environmental SciencesNational Tsing Hua UniversityHsinchu300044Taiwan
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5
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Zhang W, Zhao Z, Tan M, Adijiang A, Zhong S, Xu X, Zhao T, Ramya E, Sun L, Zhao X, Fan Z, Xiang D. Regulating the orientation of a single coordinate bond by the synergistic action of mechanical forces and electric field. Chem Sci 2023; 14:11456-11465. [PMID: 37886107 PMCID: PMC10599463 DOI: 10.1039/d3sc03892k] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 09/30/2023] [Indexed: 10/28/2023] Open
Abstract
The molecular binding orientation with respect to the electrode plays a pivotal role in determining the performance of molecular devices. However, accomplishing in situ modulation of single-molecule binding orientation remains a great challenge due to the lack of suitable testing systems and characterization approaches. To this end, by employing a developed STM-BJ technique, we demonstrate that the conductance of pyridine-anchored molecular junctions decreases as the applied voltage increases, which is determined by the repeated formation of thousands of gold-molecule-gold dynamic break junctions. In contrast, the static fixed molecular junctions (the distance between two electrodes is fixed) with identical molecules exhibit a reverse tendency as the bias voltage increases. Supported by flicker noise measurements and theoretical calculations, we provide compelling evidence that the orientation of nitrogen-gold bonds (a universal coordinate bond) in the pyridine-anchored molecular junctions can be manipulated to align with the electric field by the synergistic action of the mechanical stretching force and the electric fields, whereas either stimulus alone cannot achieve the same effect. Our study provides a framework for characterizing and regulating the orientation of a single coordinate bond, offering an approach to control electron transport through single molecular junctions.
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Affiliation(s)
- Wei Zhang
- Institute of Modern Optics, Center of Single Molecule Sciences, Key Laboratory of Micro-scale Optical Information Science and Technology, Nankai University Tianjin 300350 China
| | - Zhibin Zhao
- Institute of Modern Optics, Center of Single Molecule Sciences, Key Laboratory of Micro-scale Optical Information Science and Technology, Nankai University Tianjin 300350 China
| | - Min Tan
- Institute of Modern Optics, Center of Single Molecule Sciences, Key Laboratory of Micro-scale Optical Information Science and Technology, Nankai University Tianjin 300350 China
| | - Adila Adijiang
- Institute of Modern Optics, Center of Single Molecule Sciences, Key Laboratory of Micro-scale Optical Information Science and Technology, Nankai University Tianjin 300350 China
| | - Shurong Zhong
- Institute of Modern Optics, Center of Single Molecule Sciences, Key Laboratory of Micro-scale Optical Information Science and Technology, Nankai University Tianjin 300350 China
| | - Xiaona Xu
- Institute of Modern Optics, Center of Single Molecule Sciences, Key Laboratory of Micro-scale Optical Information Science and Technology, Nankai University Tianjin 300350 China
| | - Tianran Zhao
- Institute of Modern Optics, Center of Single Molecule Sciences, Key Laboratory of Micro-scale Optical Information Science and Technology, Nankai University Tianjin 300350 China
| | - Emusani Ramya
- Institute of Modern Optics, Center of Single Molecule Sciences, Key Laboratory of Micro-scale Optical Information Science and Technology, Nankai University Tianjin 300350 China
| | - Lu Sun
- Institute of Modern Optics, Center of Single Molecule Sciences, Key Laboratory of Micro-scale Optical Information Science and Technology, Nankai University Tianjin 300350 China
| | - Xueyan Zhao
- Institute of Modern Optics, Center of Single Molecule Sciences, Key Laboratory of Micro-scale Optical Information Science and Technology, Nankai University Tianjin 300350 China
| | - Zhiqiang Fan
- School of Physics and Electronic Science, Changsha University of Science and Technology Changsha 410114 China
| | - Dong Xiang
- Institute of Modern Optics, Center of Single Molecule Sciences, Key Laboratory of Micro-scale Optical Information Science and Technology, Nankai University Tianjin 300350 China
- School of Materials Science and Engineering, Smart Sensing Interdisciplinary Science Center, Nankai University Tianjin 300350 China
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6
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Erpenbeck A, Ke Y, Peskin U, Thoss M. How an electrical current can stabilize a molecular nanojunction. NANOSCALE 2023; 15:16333-16343. [PMID: 37766513 DOI: 10.1039/d3nr02176a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/29/2023]
Abstract
The stability of molecular junctions under transport is of the utmost importance for the field of molecular electronics. This question is often addressed within the paradigm of current-induced heating of nuclear degrees of freedom or current-induced forces acting upon the nuclei. At the same time, an essential characteristic of the failure of a molecular electronic device is its changing conductance - typically from a finite value for the intact device to zero for a device that lost its functionality. In this publication, we focus on the current-induced changes in the molecular conductance, which are inherent to molecular junctions at the limit of mechanical stability. We employ a numerically exact framework based on the hierarchical equations of motion approach, which treats both electronic and nuclear degrees of freedom on an equal footing and does not impose additional assumptions. Studying generic model systems for molecular junctions with dissociative potentials for a wide range of parameters spanning the adiabatic and the nonadiabatic regime, we find that molecular junctions that exhibit a decrease in conductance upon dissociation are more stable than junctions that are more conducting in their dissociated state. This represents a new mechanism that stabilizes molecular junctions under current. Moreover, we identify characteristic signatures in the current of breaking junctions related to the interplay between changes in the conductance and the nuclear configuration and show how these are related to properties of the leads rather than characteristics of the molecule itself.
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Affiliation(s)
- André Erpenbeck
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA.
| | - Yaling Ke
- Institute of Physics, University of Freiburg, Hermann-Herder-Strasse 3, 79104 Freiburg, Germany
| | - Uri Peskin
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Michael Thoss
- Institute of Physics, University of Freiburg, Hermann-Herder-Strasse 3, 79104 Freiburg, Germany
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7
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Siddiqui SA, Shaik S, Kalita S, Dubey KD. A porphyrin-based molecular cage guided by designed local-electric field is highly selective and efficient. Chem Sci 2023; 14:10329-10339. [PMID: 37772104 PMCID: PMC10529934 DOI: 10.1039/d3sc01720f] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 09/02/2023] [Indexed: 09/30/2023] Open
Abstract
The present work outlines a general methodology for designing efficient catalytic machineries that can easily be tweaked to meet the demands of the target reactions. This work utilizes a principle of the designed local electric field (LEF) as the driver for an efficient catalyst. It is demonstrated that by tweaking the LEF, we can catalyze the desired hydroxylation products with enantioselectivity that can be changed at will. Using computation tools, we caged a synthetic analog of heme porphyrin (HM1) and investigated the pharmaceutically relevant conversion of tetralin to tetralol, inside the modified supramolecular cage. The QM/MM calculations demonstrate a resulting catalytic efficiency with virtually absolute R-selectivity for the tetralin hydroxylation. Our calculations show that the LEF of the supramolecular cage and HM1 exert a strong electric field along the Fe-O reaction axis, which is the main driving force for enhanced reactivity. At the same time, the supramolecular cage applies a lateral LEF that regulates the enantioselectivity. We further demonstrate that swapping the charged/polar substitution in the supramolecular cage switches the lateral LEF which changes the enantioselectivity of hydroxylation from R to S.
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Affiliation(s)
- Shakir Ali Siddiqui
- Department of Chemistry, School of Natural Sciences, Shiv Nadar Institution of Eminence Delhi-NCR India
| | - Sason Shaik
- Institute of Chemistry, The Hebrew University of Jerusalem Israel Jerusalem Israel
| | - Surajit Kalita
- Department of Chemistry, School of Natural Sciences, Shiv Nadar Institution of Eminence Delhi-NCR India
| | - Kshatresh Dutta Dubey
- Department of Chemistry, School of Natural Sciences, Shiv Nadar Institution of Eminence Delhi-NCR India
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8
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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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9
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Dief EM, Darwish N. SARS-CoV-2 spike proteins react with Au and Si, are electrically conductive and denature at 3 × 10 8 V m -1: a surface bonding and a single-protein circuit study. Chem Sci 2023; 14:3428-3440. [PMID: 37006686 PMCID: PMC10055994 DOI: 10.1039/d2sc06492h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 02/17/2023] [Indexed: 02/19/2023] Open
Abstract
Developing means to characterise SARS-CoV-2 and its new variants is critical for future outbreaks. SARS-CoV-2 spike proteins have peripheral disulfide bonds (S-S), which are common in all spike proteins of SARS-CoV-2 variants, in other types of coronaviruses (e.g., SARS-CoV and MERS-CoV) and are likely to be present in future coronaviruses. Here, we demonstrate that S-S bonds in the spike S1 protein of SARS-CoV-2 react with gold (Au) and silicon (Si) electrodes. Bonding to Si is induced by a spontaneous electrochemical reaction that involves oxidation of Si-H and the reduction of the S-S bonds. The reaction of the spike protein with Au enabled single-molecule protein circuits, by connecting the spike S1 protein between two Au nano-electrodes using the scanning tunnelling microscopy-break junction (STM-BJ) technique. The conductance of a single spike S1 protein was surprisingly high and ranged between two states of 3 × 10-4 G 0 and 4 × 10-6 G 0 (1G 0 = 77.5 μS). The two conductance states are governed by the S-S bonds reaction with Au which controls the orientation of the protein in the circuit, and via which different electron pathways are created. The 3 × 10-4 G 0 level is attributed to a single SARS-CoV-2 protein connecting to the two STM Au nano-electrodes from the receptor binding domain (RBD) subunit and the S1/S2 cleavage site. A lower 4 × 10-6 G 0 conductance is attributed to the spike protein connecting to the STM electrodes from the RBD subunit and the N-terminal domain (NTD). These conductance signals are only observed at electric fields equal to or lower than 7.5 × 107 V m-1. At an electric field of 1.5 × 108 V m-1, the original conductance magnitude decreases accompanied by a lower junction yield, suggesting a change in the structure of the spike protein in the electrified junction. Above an electric field of 3 × 108 V m-1, the conducting channels are blocked and this is attributed to the spike protein denaturing in the nano-gap. These findings open new venues for developing coronavirus-capturing materials and offer an electrical method for analysing, detecting and potentially electrically deactivating coronaviruses and their future variants.
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Affiliation(s)
- Essam M Dief
- School of Molecular and Life Sciences, Curtin University Bentley WA 6102 Australia
| | - Nadim Darwish
- School of Molecular and Life Sciences, Curtin University Bentley WA 6102 Australia
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10
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Zhang B, Schaack C, Prindle CR, Vo EA, Aziz M, Steigerwald ML, Berkelbach TC, Nuckolls C, Venkataraman L. Electric fields drive bond homolysis. Chem Sci 2023; 14:1769-1774. [PMID: 36819847 PMCID: PMC9931054 DOI: 10.1039/d2sc06411a] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 01/15/2023] [Indexed: 01/17/2023] Open
Abstract
Electric fields have been used to control and direct chemical reactions in biochemistry and enzymatic catalysis, yet directly applying external electric fields to activate reactions in bulk solution and to characterize them ex situ remains a challenge. Here we utilize the scanning tunneling microscope-based break-junction technique to investigate the electric field driven homolytic cleavage of the radical initiator 4-(methylthio)benzoic peroxyanhydride at ambient temperatures in bulk solution, without the use of co-initiators or photochemical activators. Through time-dependent ex situ quantification by high performance liquid chromatography using a UV-vis detector, we find that the electric field catalyzes the reaction. Importantly, we demonstrate that the reaction rate in a field increases linearly with the solvent dielectric constant. Using density functional theory calculations, we show that the applied electric field decreases the dissociation energy of the O-O bond and stabilizes the product relative to the reactant due to their different dipole moments.
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Affiliation(s)
- Boyuan Zhang
- Department of Applied Physics and Applied Mathematics, Columbia University New York 10027 New York US
| | - Cedric Schaack
- Department of Chemistry, Columbia University New York 10027 New York USA
| | | | - Ethan A. Vo
- Department of Chemistry, Columbia UniversityNew York 10027New YorkUSA
| | - Miriam Aziz
- Department of Chemistry, Columbia University New York 10027 New York USA
| | | | - Timothy C. Berkelbach
- Department of Chemistry, Columbia UniversityNew York 10027New YorkUSA,Center for Computational Quantum Physics, Flatiron InstituteNew YorkNew York10010USA
| | - Colin Nuckolls
- Department of Chemistry, Columbia University New York 10027 New York USA
| | - Latha Venkataraman
- Department of Applied Physics and Applied Mathematics, Columbia University New York 10027 New York US .,Department of Chemistry, Columbia University New York 10027 New York USA
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11
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Wu J, Long T, Wang H, Liang JX, Zhu C. Oriented External Electric Fields Regurating the Reaction Mechanism of CH 4 Oxidation Catalyzed by Fe(IV)-Oxo-Corrolazine: Insight from Density Functional Calculations. Front Chem 2022; 10:896944. [PMID: 35844657 PMCID: PMC9277104 DOI: 10.3389/fchem.2022.896944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 06/08/2022] [Indexed: 11/13/2022] Open
Abstract
Methane is the simplest alkane and can be used as an alternative energy source for oil and coal, but the greenhouse effect caused by its leakage into the air is not negligible, and its conversion into liquid methanol not only facilitates transportation, but also contributes to carbon neutrality. In order to find an efficient method for converting methane to methanol, CH4 oxidation catalyzed by Fe(IV)-Oxo-corrolazine (Fe(IV)-Oxo-Cz) and its reaction mechanism regulation by oriented external electric fields (OEEFs) are systematically studied by density functional calculations. The calculations show that Fe(IV)-Oxo-Cz can abstract one H atom from CH4 to form the intermediate with OH group connecting on the corrolazine ring, with the energy barrier of 25.44 kcal mol-1. And then the product methanol is formed through the following rebound reaction. Moreover, the energy barrier can be reduced to 20.72 kcal mol-1 through a two-state reaction pathway. Furthermore, the effect of OEEFs on the reaction is investigated. We found that OEEFs can effectively regulate the reaction by adjusting the stability of the reactant and the transition state through the interaction of electric field-molecular dipole moment. When the electric field is negative, the energy barrier of the reaction decreases with the increase of electric intensity. Moreover, the OEEF aligned along the intrinsic Fe‒O reaction axis can effectively regulate the ability of forming the OH on the corrolazine ring by adjusting the charges of O and H atoms. When the electric field intensity is -0.010 a.u., the OH can be directly rebounded to the CH3· before it is connecting on the corrolazine ring, thus forming the product directly from the transition state without passing through the intermediate with only an energy barrier of 17.34 kcal mol-1, which greatly improves the selectivity of the reaction.
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Affiliation(s)
| | | | | | - Jin-Xia Liang
- School of Chemistry and Chemical Engineering, Guizhou University, Guiyang, China
| | - Chun Zhu
- School of Chemistry and Chemical Engineering, Guizhou University, Guiyang, China
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12
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Ke Y, Kaspar C, Erpenbeck A, Peskin U, Thoss M. Nonequilibrium reaction rate theory: Formulation and implementation within the hierarchical equations of motion approach. J Chem Phys 2022; 157:034103. [DOI: 10.1063/5.0098545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The study of chemical reactions in environments under nonequilibrium conditions has been of interest recently in a variety of contexts, including current-induced reactions in molecular junctions and scanning tunneling microscopy experiments. In this work, we outline a fully quantum mechanical, numerically exact approach to describe chemical reaction rates in such nonequilibrium situations. The approach is based on an extension of the flux correlation function formalism to nonequilibrium conditions and uses a mixed real and imaginary time hierarchical equations of motion approach for the calculation of rate constants. As a specific example, we investigate current-induced intramolecular proton transfer reactions in a molecular junction for different applied bias voltages and molecule-lead coupling strengths.
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Affiliation(s)
- Yaling Ke
- Institute of Physics, Albert-Ludwigs-Universität Freiburg, Germany
| | | | | | - Uri Peskin
- Chemistry, Technion Israel Institute of Technology, Israel
| | - Michael Thoss
- University of Freiburg Institute of Physics, Germany
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13
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Yuan S, Qian Q, Zhou Y, Zhao S, Lin L, Duan P, Xu X, Shi J, Xu W, Feng A, Shi J, Yang Y, Hong W. Tracking Confined Reaction Based on Host-Guest Interaction Using Single-Molecule Conductance Measurement. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2104554. [PMID: 34796644 DOI: 10.1002/smll.202104554] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 09/30/2021] [Indexed: 06/13/2023]
Abstract
The host-guest interaction acts as an essential part of supramolecular chemistry, which can be applied in confined reaction. However, it is challenging to obtain the dynamic process during confined reactions below micromolar concentrations. In this work, a new method is provided to characterize the dimerization process of the guest 1,2-bis(4-pyridinyl) ethylene in host cucurbit[8]curil using scanning tunneling microscope-break junction (STM-BJ) technique. The guest reaction kinetics is quantitatively by nuclear magnetic resonance (NMR) and in situ single-molecule junctions. It is found that in the single-molecule conductance measurements, the electrical signals of the reactants with a concentration as low as 5 × 10-6 m are clearly detected, and the reaction kinetics at micromolar concentrations are further obtained. However, in NMR measurements, the characteristic peak signal of the reactants is undetectable when the concentration of the reactants is lower than 0.5 × 10-3 m and it cannot be quantified. In addition, the strong electric field from the nanogap accelerates the reaction. This work reveals that single-molecule STM-BJ techniques are more sensitive for tracking confined reactions than that by NMR techniques and can be used to study effect of extremely strong electric field on kinetics.
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Affiliation(s)
- Saisai Yuan
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Pen-Tung Sah Institute of Micro-Nano Science and Technology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Qiaozan Qian
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Pen-Tung Sah Institute of Micro-Nano Science and Technology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Yu Zhou
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Pen-Tung Sah Institute of Micro-Nano Science and Technology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Shiqiang Zhao
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Pen-Tung Sah Institute of Micro-Nano Science and Technology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Luchun Lin
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Pen-Tung Sah Institute of Micro-Nano Science and Technology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Ping Duan
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Pen-Tung Sah Institute of Micro-Nano Science and Technology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Xinghai Xu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Pen-Tung Sah Institute of Micro-Nano Science and Technology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Jie Shi
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Pen-Tung Sah Institute of Micro-Nano Science and Technology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Wei Xu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Pen-Tung Sah Institute of Micro-Nano Science and Technology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Anni Feng
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Pen-Tung Sah Institute of Micro-Nano Science and Technology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Jia Shi
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Pen-Tung Sah Institute of Micro-Nano Science and Technology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Yang Yang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Pen-Tung Sah Institute of Micro-Nano Science and Technology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Wenjing Hong
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Pen-Tung Sah Institute of Micro-Nano Science and Technology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
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14
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Aggarwal A, Kaliginedi V, Maiti PK. Quantum Circuit Rules for Molecular Electronic Systems: Where Are We Headed Based on the Current Understanding of Quantum Interference, Thermoelectric, and Molecular Spintronics Phenomena? NANO LETTERS 2021; 21:8532-8544. [PMID: 34622657 DOI: 10.1021/acs.nanolett.1c02390] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
In this minireview, we discuss important aspects of the various quantum phenomena (such as quantum interference, spin-dependent charge transport, and thermoelectric effects) relevant in single-molecule charge transport and list some of the basic circuit rules devised for different molecular systems. These quantum phenomena, in conjunction with the existing empirical circuit rules, can help in predicting some of the structure-property relationships in molecular circuits. However, a universal circuit law that predicts the charge transport properties of a molecular circuit has not been derived yet. Having such law(s) will help to design and build a complex molecular device leading to exciting unique applications that are not possible with the traditional silicon-based technologies. Based on the existing knowledge in the literature, here we open the discussion on the possible future research directions for deriving unified circuit law(s) to predict the charge transport in complex single-molecule circuits.
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Affiliation(s)
- Abhishek Aggarwal
- Center for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560012, India
| | - Veerabhadrarao Kaliginedi
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India
| | - Prabal K Maiti
- Center for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560012, India
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15
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Barragán A, Robles R, Lorente N, Vitali L. Power discontinuity and shift of the energy onset of a molecular de-bromination reaction induced by hot-electron tunneling. NANOSCALE 2021; 13:15215-15219. [PMID: 34494638 DOI: 10.1039/d1nr04229g] [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
Understanding the mechanism of molecular dissociation under applied bias is a fundamental requirement to progress in (electro)-catalysis as well as in (opto)-electronics. The working conditions of a molecular-based device and the stability of chemical bonds can be addressed in metal-organic junctions by injecting electrons in tunneling conditions. Here, we have correlated the energy of de-bromination of an aryl group with its density of states in a self-assembled dimeric structure of 4'-bromo-4-mercaptobiphenyl adsorbed on a Au(111) surface. We have observed that the electron-energy range where the molecule is chemically stable can be extended, shifting the bias threshold for the rupture of the -C-Br bond continuously from about 2.4 to 4.4 V by changing the electron current. Correspondingly, the power needed for the dissociation drops sharply at 3.6 V, identifying different reaction regimes and the contribution of different molecular resonance states.
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Affiliation(s)
- Ana Barragán
- Donostia International Physics Center (DIPC), Paseo M Lardizabal 4, 20018 San Sebastián, Spain.
- Advanced Polymers and Materials: Physics, Chemistry and Technology, Chemistry Faculty (UPV/EHU), Paseo M Lardizabal 3, 20018 San Sebastián, Spain
- Centro de Física de Materiales CFM/MPC(CSIC-UPV/EHU), Paseo M Lardizabal 5, 20018 San Sebastián, Spain.
| | - Roberto Robles
- Centro de Física de Materiales CFM/MPC(CSIC-UPV/EHU), Paseo M Lardizabal 5, 20018 San Sebastián, Spain.
| | - Nicolás Lorente
- Donostia International Physics Center (DIPC), Paseo M Lardizabal 4, 20018 San Sebastián, Spain.
- Centro de Física de Materiales CFM/MPC(CSIC-UPV/EHU), Paseo M Lardizabal 5, 20018 San Sebastián, Spain.
| | - Lucia Vitali
- Donostia International Physics Center (DIPC), Paseo M Lardizabal 4, 20018 San Sebastián, Spain.
- Advanced Polymers and Materials: Physics, Chemistry and Technology, Chemistry Faculty (UPV/EHU), Paseo M Lardizabal 3, 20018 San Sebastián, Spain
- Centro de Física de Materiales CFM/MPC(CSIC-UPV/EHU), Paseo M Lardizabal 5, 20018 San Sebastián, Spain.
- Ikerbasque Research Foundation for Science, Plaza Euskadi, 5, Bilbao 48009, Spain
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16
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Ke Y, Erpenbeck A, Peskin U, Thoss M. Unraveling current-induced dissociation mechanisms in single-molecule junctions. J Chem Phys 2021; 154:234702. [PMID: 34241274 DOI: 10.1063/5.0053828] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Understanding current-induced bond rupture in single-molecule junctions is both of fundamental interest and a prerequisite for the design of molecular junctions, which are stable at higher-bias voltages. In this work, we use a fully quantum mechanical method based on the hierarchical quantum master equation approach to analyze the dissociation mechanisms in molecular junctions. Considering a wide range of transport regimes, from off-resonant to resonant, non-adiabatic to adiabatic transport, and weak to strong vibronic coupling, our systematic study identifies three dissociation mechanisms. In the weak and intermediate vibronic coupling regime, the dominant dissociation mechanism is stepwise vibrational ladder climbing. For strong vibronic coupling, dissociation is induced via multi-quantum vibrational excitations triggered either by a single electronic transition at high bias voltages or by multiple electronic transitions at low biases. Furthermore, the influence of vibrational relaxation on the dissociation dynamics is analyzed and strategies for improving the stability of molecular junctions are discussed.
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Affiliation(s)
- Yaling Ke
- Institute of Physics, Albert-Ludwig University Freiburg, Hermann-Herder-Strasse 3, 79104 Freiburg, Germany
| | - André Erpenbeck
- School of Chemistry, The Raymond and Beverley Sackler Center for Computational Molecular and Materials Science, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Uri Peskin
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Michael Thoss
- Institute of Physics, Albert-Ludwig University Freiburg, Hermann-Herder-Strasse 3, 79104 Freiburg, Germany
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17
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Fereiro JA, Pecht I, Sheves M, Cahen D. Inelastic Electron Tunneling Spectroscopic Analysis of Bias-Induced Structural Changes in a Solid-State Protein Junction. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2008218. [PMID: 33783130 DOI: 10.1002/smll.202008218] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 02/10/2021] [Indexed: 05/25/2023]
Abstract
A central issue in protein electronics is how far the structural stability of the protein is preserved under the very high electrical field that it will experience once a bias voltage is applied. This question is studied on the redox protein Azurin in the solid-state Au/protein/Au junction by monitoring protein vibrations during current transport under applied bias, up to ≈1 GV m-1 , by electrical detection of inelastic electron transport effects. Characteristic vibrational modes, such as CH stretching, amide (NH) bending, and AuS (of the bonds that connect the protein to an Au electrode), are not found to change noticeably up to 1.0 V. At >1.0 V, the NH bending and CH stretching inelastic features have disappeared, while the AuS features persist till ≈2 V, i.e., the proteins remain Au bound. Three possible causes for the disappearance of the NH and CH inelastic features at high bias, namely, i) resonance transport, ii) metallic filament formation, and iii) bond rupture leading to structural changes in the protein are proposed and tested. The results support the last option and indicate that spectrally resolved inelastic features can serve to monitor in operando structural stability of biological macromolecules while they serve as electronic current conduit.
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Affiliation(s)
- Jerry A Fereiro
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Israel Pecht
- Department of Immunology, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Mordechai Sheves
- Department of Organic Chemistry, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - David Cahen
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, 7610001, Israel
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18
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Preston RJ, Gelin MF, Kosov DS. First-passage time theory of activated rate chemical processes in electronic molecular junctions. J Chem Phys 2021; 154:114108. [PMID: 33752339 DOI: 10.1063/5.0045652] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Confined nanoscale spaces, electric fields, and tunneling currents make the molecular electronic junction an experimental device for the discovery of new out-of-equilibrium chemical reactions. Reaction-rate theory for current-activated chemical reactions is developed by combining the Keldysh nonequilibrium Green's function treatment of electrons, Fokker-Planck description of the reaction coordinate, and Kramers first-passage time calculations. The nonequilibrium Green's functions (NEGF) provide an adiabatic potential as well as a diffusion coefficient and temperature with local dependence on the reaction coordinate. Van Kampen's Fokker-Planck equation, which describes a Brownian particle moving in an external potential in an inhomogeneous medium with a position-dependent friction and diffusion coefficient, is used to obtain an analytic expression for the first-passage time. The theory is applied to several transport scenarios: a molecular junction with a single reaction coordinate dependent molecular orbital and a model diatomic molecular junction. We demonstrate the natural emergence of Landauer's blowtorch effect as a result of the interplay between the configuration dependent viscosity and diffusion coefficients. The resultant localized heating in conjunction with the bond-deformation due to current-induced forces is shown to be the determining factors when considering chemical reaction rates, each of which results from highly tunable parameters within the system.
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Affiliation(s)
- Riley J Preston
- College of Science and Engineering, James Cook University, Townsville, QLD 4811, Australia
| | - Maxim F Gelin
- School of Sciences, Hangzhou Dianzi University, 310018 Hangzhou, China
| | - Daniel S Kosov
- College of Science and Engineering, James Cook University, Townsville, QLD 4811, Australia
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19
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Zang Y, Fung ED, Fu T, Ray S, Garner MH, Borges A, Steigerwald ML, Patil S, Solomon G, Venkataraman L. Voltage-Induced Single-Molecule Junction Planarization. NANO LETTERS 2021; 21:673-679. [PMID: 33337876 DOI: 10.1021/acs.nanolett.0c04260] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Probing structural changes of a molecule induced by charge transfer is important for understanding the physicochemical properties of molecules and developing new electronic devices. Here, we interrogate the structural changes of a single diketopyrrolopyrrole (DPP) molecule induced by charge transport at a high bias using scanning tunneling microscope break junction (STM-BJ) techniques. Specifically, we demonstrate that application of a high bias increases the average nonresonant conductance of single Au-DPP-Au junctions. We infer from the increased conductance that resonant charge transport induces planarization of the molecular backbone. We further show that this conformational planarization is assisted by thermally activated junction reorganization. The planarization only occurs under specific electronic conditions, which we rationalize by ab initio calculations. These results emphasize the need for a comprehensive view of single-molecule junctions which includes both the electronic properties and structure of the molecules and the electrodes when designing electrically driven single-molecule motors.
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Affiliation(s)
- Yaping Zang
- Department of Applied Physics, Columbia University, New York, New York 10027, United States
| | - E-Dean Fung
- Department of Applied Physics, Columbia University, New York, New York 10027, United States
| | - Tianren Fu
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Suman Ray
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
| | - Marc H Garner
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Copenhagen Ø DK-2100, Denmark
| | - Anders Borges
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Copenhagen Ø DK-2100, Denmark
| | - Michael L Steigerwald
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Satish Patil
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
| | - Gemma Solomon
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Copenhagen Ø DK-2100, Denmark
| | - Latha Venkataraman
- Department of Applied Physics, Columbia University, New York, New York 10027, United States
- Department of Chemistry, Columbia University, New York, New York 10027, United States
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20
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Gao T, Pan Z, Cai Z, Zheng J, Tang C, Yuan S, Zhao SQ, Bai H, Yang Y, Shi J, Xiao Z, Liu J, Hong W. Electric field-induced switching among multiple conductance pathways in single-molecule junctions. Chem Commun (Camb) 2021; 57:7160-7163. [PMID: 34184023 DOI: 10.1039/d1cc02111g] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Here, we report the switching among multiple conductance pathways achieved by sliding the scanning tunneling microscope tip among different binding sites under different electric fields. With an increase in the electric field, high molecular conductance states appear, suggesting the formation of different configurations in single-molecule junctions. The switch can be operated in situ and reversibly, which is also confirmed by the apparent conductance conversion in I-V measurements. Theoretical simulations also agree well with the experimental results, which implies that the electric field enables the possibility to trigger switching in single-molecule junctions.
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Affiliation(s)
- Tengyang Gao
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
| | - Zhichao Pan
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
| | - Zhuanyun Cai
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
| | - Jueting Zheng
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
| | - Chun Tang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
| | - Saisai Yuan
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
| | - Shi Qiang Zhao
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
| | - Hua Bai
- College of Materials, Xiamen University, Xiamen 361005, China
| | - Yang Yang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
| | - Jia Shi
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
| | - Zongyuan Xiao
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
| | - Junyang Liu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
| | - Wenjing Hong
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
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21
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Zeng BF, Wang G, Qian QZ, Chen ZX, Zhang XG, Lu ZX, Zhao SQ, Feng AN, Shi J, Yang Y, Hong W. Selective Fabrication of Single-Molecule Junctions by Interface Engineering. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e2004720. [PMID: 33155382 DOI: 10.1002/smll.202004720] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 09/14/2020] [Indexed: 06/11/2023]
Abstract
Recent progress in addressing electrically driven single-molecule behaviors has opened up a path toward the controllable fabrication of molecular devices. Herein, the selective fabrication of single-molecule junctions is achieved by employing the external electric field. For molecular junctions with methylthio (-SMe), thioacetate (-SAc), amine (-NH2 ), and pyridyl (-PY), the evolution of their formation probabilities along with the electric field is extracted from the plateau analysis of individual single-molecule break junction traces. With the increase of the electric field, the SMe-anchored molecules show a different trend in the formation probability compared to the other molecular junctions, which is consistent with the density functional theory calculations. Furthermore, switching from an SMe-anchored junction to an SAc-anchored junction is realized by altering the electric field in a mixed solution. The results in this work provide a new approach to the controllable fabrication and modulation of single-molecule junctions and other bottom-up nanodevices at molecular scales.
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Affiliation(s)
- Biao-Feng Zeng
- Pen-Tung Sah Institute of Micro-Nano Science and Technology, College of Chemistry and Chemical Engineering and State Key Laboratory of Physical Chemistry of Solid Surfaces, IKKEM, iChEM, Xiamen University, Xiamen, 361005, China
| | - Gan Wang
- Pen-Tung Sah Institute of Micro-Nano Science and Technology, College of Chemistry and Chemical Engineering and State Key Laboratory of Physical Chemistry of Solid Surfaces, IKKEM, iChEM, Xiamen University, Xiamen, 361005, China
| | - Qiao-Zan Qian
- Pen-Tung Sah Institute of Micro-Nano Science and Technology, College of Chemistry and Chemical Engineering and State Key Laboratory of Physical Chemistry of Solid Surfaces, IKKEM, iChEM, Xiamen University, Xiamen, 361005, China
| | - Zhi-Xin Chen
- Pen-Tung Sah Institute of Micro-Nano Science and Technology, College of Chemistry and Chemical Engineering and State Key Laboratory of Physical Chemistry of Solid Surfaces, IKKEM, iChEM, Xiamen University, Xiamen, 361005, China
| | - Xia-Guang Zhang
- School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, 453007, China
| | - Zhi-Xing Lu
- Pen-Tung Sah Institute of Micro-Nano Science and Technology, College of Chemistry and Chemical Engineering and State Key Laboratory of Physical Chemistry of Solid Surfaces, IKKEM, iChEM, Xiamen University, Xiamen, 361005, China
| | - Shi-Qiang Zhao
- Pen-Tung Sah Institute of Micro-Nano Science and Technology, College of Chemistry and Chemical Engineering and State Key Laboratory of Physical Chemistry of Solid Surfaces, IKKEM, iChEM, Xiamen University, Xiamen, 361005, China
| | - An-Ni Feng
- Pen-Tung Sah Institute of Micro-Nano Science and Technology, College of Chemistry and Chemical Engineering and State Key Laboratory of Physical Chemistry of Solid Surfaces, IKKEM, iChEM, Xiamen University, Xiamen, 361005, China
| | - Jia Shi
- Pen-Tung Sah Institute of Micro-Nano Science and Technology, College of Chemistry and Chemical Engineering and State Key Laboratory of Physical Chemistry of Solid Surfaces, IKKEM, iChEM, Xiamen University, Xiamen, 361005, China
| | - Yang Yang
- Pen-Tung Sah Institute of Micro-Nano Science and Technology, College of Chemistry and Chemical Engineering and State Key Laboratory of Physical Chemistry of Solid Surfaces, IKKEM, iChEM, Xiamen University, Xiamen, 361005, China
| | - Wenjing Hong
- Pen-Tung Sah Institute of Micro-Nano Science and Technology, College of Chemistry and Chemical Engineering and State Key Laboratory of Physical Chemistry of Solid Surfaces, IKKEM, iChEM, Xiamen University, Xiamen, 361005, China
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22
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Preston RJ, Honeychurch TD, Kosov DS. Cooling molecular electronic junctions by AC current. J Chem Phys 2020; 153:121102. [PMID: 33003743 DOI: 10.1063/5.0019178] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Electronic current flowing in a molecular electronic junction dissipates significant amounts of energy to vibrational degrees of freedom, straining and rupturing chemical bonds and often quickly destroying the integrity of the molecular device. The infamous mechanical instability of molecular electronic junctions critically limits performance and lifespan and raises questions as to the technological viability of single-molecule electronics. Here, we propose a practical scheme for cooling the molecular vibrational temperature via application of an AC voltage over a large, static operational DC voltage bias. Using nonequilibrium Green's functions, we computed the viscosity and diffusion coefficient experienced by nuclei surrounded by a nonequilibrium "sea" of periodically driven, current-carrying electrons. The effective molecular junction temperature is deduced by balancing the viscosity and diffusion coefficients. Our calculations show the opportunity of achieving in excess of 40% cooling of the molecular junction temperature while maintaining the same average current.
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Affiliation(s)
- Riley J Preston
- College of Science and Engineering, James Cook University, Townsville, QLD 4811, Australia
| | - Thomas D Honeychurch
- College of Science and Engineering, James Cook University, Townsville, QLD 4811, Australia
| | - Daniel S Kosov
- College of Science and Engineering, James Cook University, Townsville, QLD 4811, Australia
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23
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Zhang L, Ciampi S, Gooding JJ. Electrostatic Regulation of TEMPO Oxidation by Distal Molecular Charges. ChemElectroChem 2020. [DOI: 10.1002/celc.202000817] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Long Zhang
- School of Chemistry, The Australian Centre for NanoMedicine and ARC Centre of Excellence for Convergent Bio-Nano Science and TechnologyThe University of New South Wales Sydney, New South Wales 2052 Australia
| | - Simone Ciampi
- Department of Chemistry, Curtin Institute of Functional Molecules and InterfacesCurtin University Bentley, Western Australia 6102 Australia
| | - J. Justin Gooding
- School of Chemistry, The Australian Centre for NanoMedicine and ARC Centre of Excellence for Convergent Bio-Nano Science and TechnologyThe University of New South Wales Sydney, New South Wales 2052 Australia
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24
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Kuperman M, Nagar L, Peskin U. Mechanical Stabilization of Nanoscale Conductors by Plasmon Oscillations. NANO LETTERS 2020; 20:5531-5537. [PMID: 32538634 PMCID: PMC7467764 DOI: 10.1021/acs.nanolett.0c02187] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 06/15/2020] [Indexed: 06/10/2023]
Abstract
External driving of the Fermion reservoirs interacting with a nanoscale charge-conductor is shown to enhance its mechanical stability during resonant tunneling. This counterintuitive cooling effect is predicted despite the net energy flow into the device. Field-induced plasmon oscillations stir the energy distribution of charge carriers near the reservoir's chemical potentials into a nonequilibrium state with favored transport of low-energy electrons. Consequently, excess heating of mechanical degrees of freedom in the conductor is suppressed. We demonstrate and analyze this effect for a generic model of mechanical instability in nanoelectronic devices, covering a broad range of parameters. Plasmon-induced stabilization is suggested as a feasible strategy to confront a major problem of current-induced heating and breakdown of nanoscale systems operating far from equilibrium.
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Affiliation(s)
- Maayan Kuperman
- Schulich
Faculty of Chemistry and The Russell Berrie Nanotechnology Institute, Technion − Israel Institute of Technology, Haifa 32000, Israel
| | - Linoy Nagar
- Schulich
Faculty of Chemistry and The Russell Berrie Nanotechnology Institute, Technion − Israel Institute of Technology, Haifa 32000, Israel
| | - Uri Peskin
- Schulich
Faculty of Chemistry and The Russell Berrie Nanotechnology Institute, Technion − Israel Institute of Technology, Haifa 32000, Israel
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25
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Dutta Dubey K, Stuyver T, Kalita S, Shaik S. Solvent Organization and Rate Regulation of a Menshutkin Reaction by Oriented External Electric Fields are Revealed by Combined MD and QM/MM Calculations. J Am Chem Soc 2020; 142:9955-9965. [PMID: 32369357 PMCID: PMC7304904 DOI: 10.1021/jacs.9b13029] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Indexed: 01/01/2023]
Abstract
When and how do external electric fields (EEFs) lead to catalysis in the presence of a (polar or nonpolar) solvent? This is the question that is addressed here using a combination of molecular dynamics (MD) simulations, quantum mechanical/molecular mechanical calculations with EEF, and quantum mechanical/(local) electric field calculations. The paper focuses on a model reaction, the Menshutkin reaction between CH3I and pyridine in three solvents of varying polarity. Using MD simulations, we find that the EEF causes the solvent to undergo organization; the solvent molecules gradually align with the applied field as the field strength increases. The collective orientation of the solvent molecules modifies the electrostatic environment around the Menshutkin species and induces a global electric field pointing in the opposite direction of the applied EEF. The combination of these two entangled effects leads to partial or complete screening of the EEF, with the extent of screening being proportional to the polarity/polarizability of the solvent. Nevertheless, we find that catalysis of the Menshutkin reaction inevitably emerges once the EEF exceeds the opposing field of the organizing solvent, i.e., once polarization of the Menshutkin complex is observed to set in. Overall, our analysis provides a lucid and pictorial interpretation of the behavior of solutions in the presence of EEFs and indicates that EEF-mediated catalysis should, in principle, be feasible in bulk setups, especially for nonpolar and mildly polar solvents. By application of the charge-transfer paradigm, it is shown that the emergence of OEEF catalysis in solution can be generalized to other reactions as well.
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Affiliation(s)
- Kshatresh Dutta Dubey
- Department
of Chemistry & Center for Informatics, Shiv Nadar University, NH91 Tehsil Dadri, Greater Noida, Uttar Pradesh 201314, India
| | - Thijs Stuyver
- Institute
of Chemistry, Edmond J. Safra Campus at Givat Ram, The Hebrew University, Jerusalem 9190400, Israel
- Algemene
Chemie, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Surajit Kalita
- Department
of Chemistry & Center for Informatics, Shiv Nadar University, NH91 Tehsil Dadri, Greater Noida, Uttar Pradesh 201314, India
| | - Sason Shaik
- Institute
of Chemistry, Edmond J. Safra Campus at Givat Ram, The Hebrew University, Jerusalem 9190400, Israel
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26
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Stuyver T, Huang J, Mallick D, Danovich D, Shaik S. TITAN: A Code for Modeling and Generating Electric Fields—Features and Applications to Enzymatic Reactivity. J Comput Chem 2019; 41:74-82. [DOI: 10.1002/jcc.26072] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 08/22/2019] [Accepted: 08/31/2019] [Indexed: 12/24/2022]
Affiliation(s)
- Thijs Stuyver
- Institute of Chemistry, The Lise Meitner‐Minerva Center for Computational Quantum ChemistryHebrew University of Jerusalem Givat Ram Campus Jerusalem 91904 Israel
- Algemene ChemieVrije Universiteit Brussel Pleinlaan 2 1050 Brussels Belgium
| | - Jing Huang
- Institute of Chemistry, The Lise Meitner‐Minerva Center for Computational Quantum ChemistryHebrew University of Jerusalem Givat Ram Campus Jerusalem 91904 Israel
- College of Environmental and Biological EngineeringPutian University Putian Fujian 351100 China
| | - Dibyendu Mallick
- Institute of Chemistry, The Lise Meitner‐Minerva Center for Computational Quantum ChemistryHebrew University of Jerusalem Givat Ram Campus Jerusalem 91904 Israel
- Department of ChemistryPresidency University Kolkata 700073 India
| | - David Danovich
- Institute of Chemistry, The Lise Meitner‐Minerva Center for Computational Quantum ChemistryHebrew University of Jerusalem Givat Ram Campus Jerusalem 91904 Israel
| | - Sason Shaik
- Institute of Chemistry, The Lise Meitner‐Minerva Center for Computational Quantum ChemistryHebrew University of Jerusalem Givat Ram Campus Jerusalem 91904 Israel
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27
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Stuyver T, Danovich D, Joy J, Shaik S. External electric field effects on chemical structure and reactivity. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2019. [DOI: 10.1002/wcms.1438] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Thijs Stuyver
- Institute of Chemistry The Hebrew University Jerusalem Israel
- Algemene Chemie Vrije Universiteit Brussel Brussels Belgium
| | - David Danovich
- Institute of Chemistry The Hebrew University Jerusalem Israel
| | - Jyothish Joy
- Institute of Chemistry The Hebrew University Jerusalem Israel
| | - Sason Shaik
- Institute of Chemistry The Hebrew University Jerusalem Israel
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28
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Stuyver T, Danovich D, De Proft F, Shaik S. Electrophilic Aromatic Substitution Reactions: Mechanistic Landscape, Electrostatic and Electric-Field Control of Reaction Rates, and Mechanistic Crossovers. J Am Chem Soc 2019; 141:9719-9730. [PMID: 31140274 DOI: 10.1021/jacs.9b04982] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This study investigates the rich mechanistic landscape of the iconic electrophilic aromatic substitution (EAS) reaction class, in the gas phase, in solvents, and under stimulation by oriented external electric fields. The study uses DFT calculations, complemented by a qualitative valence bond (VB) perspective. We construct a comprehensive and unifying framework that elucidates the many surprising mechanistic features, uncovered in recent years, of this class of reactions. For example, one of the puzzling issues which have attracted significant interest recently is the finding of a variety of concerted mechanisms that do not involve the formation of σ-complex intermediates, in apparent contradiction to the generally accepted textbook mechanism. Our VB modeling elucidates the existence of both the concerted and stepwise mechanisms and uncovers the root causes and necessary conditions for the appearance of these intermediates. Furthermore, our VB analysis offers insight into the potential applications of external electric fields as smart, green, and selective catalysts, which can control at will reaction rates, as well as mechanistic crossovers, for this class of reactions. Finally, we highlight how understanding of the electric fields effect on the EAS reaction could lead to the formulation of guiding principles for the design of improved heterogeneous catalysts. Overall, our analysis underscores the powerful synergy offered by combining molecular orbital and VB theory to tackle interesting and challenging mechanistic questions in chemistry.
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Affiliation(s)
- Thijs Stuyver
- Department of Organic Chemistry and the Lise Meitner-Minerva Centre for Computational Quantum Chemistry , The Hebrew University , Jerusalem 91904 , Israel.,Algemene Chemie , Vrije Universiteit Brussel , Pleinlaan 2 , 1050 Brussels , Belgium
| | - David Danovich
- Department of Organic Chemistry and the Lise Meitner-Minerva Centre for Computational Quantum Chemistry , The Hebrew University , Jerusalem 91904 , Israel
| | - Frank De Proft
- Algemene Chemie , Vrije Universiteit Brussel , Pleinlaan 2 , 1050 Brussels , Belgium
| | - Sason Shaik
- Department of Organic Chemistry and the Lise Meitner-Minerva Centre for Computational Quantum Chemistry , The Hebrew University , Jerusalem 91904 , Israel
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29
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Sarsa A, Alcaraz-Pelegrina JM, Le Sech C. Exclusion principle repulsion effects on the covalent bond beyond the Born-Oppenheimer approximation. Phys Chem Chem Phys 2019; 21:10411-10416. [PMID: 31065634 DOI: 10.1039/c9cp01063g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The changes in the covalent bond of the hydrogen molecule limited in space by a spherical hard boundary are studied. The sphere is moved along an axis parallel or orthogonal to the molecular axis. The diffusion Monte Carlo approach is used to solve the Schrödinger equation with the relevant boundary conditions and to evaluate the changes in the bond energy versus the location of the sphere. The vertical and lateral quantum forces exerted on the sphere are evaluated by calculating the energy derivative versus the distances to the sphere. The results show that the quantum forces present an important dependence on the distance and vanish rapidly as the separation between the sphere and the molecule increases. In the limiting case the molecular bond breaks due to the electronic depletion induced in the covalent bond. An application of this study is the modelisation of the forces exerted on the passivated cantilever of an atomic force microscope probing the electron cloud in the contact mode in the Pauli exclusion regime.
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Affiliation(s)
- A Sarsa
- Departamento de Física, Campus de Rabanales Edif. C2, Universidad de Córdoba, E-14071 Córdoba, Spain.
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30
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Wang C, Danovich D, Chen H, Shaik S. Oriented External Electric Fields: Tweezers and Catalysts for Reactivity in Halogen-Bond Complexes. J Am Chem Soc 2019; 141:7122-7136. [PMID: 30945542 DOI: 10.1021/jacs.9b02174] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This theoretical study establishes ways of controlling and enabling an uncommon chemical reaction, the displacement reaction, B:---(X-Y) → (B-X)+ + :Y-, which is nascent from a B:---(X-Y) halogen bond (XB) by nucleophilic attack of the base, B:, on the halogen, X. In most of the 14 cases examined, these reactions possess high barriers either in the gas phase (where the X-Y bond dissociates to radicals) or in solvents such as CH2Cl2 and CH3CN (which lead to endothermic processes). Thus, generally, the XB species are trapped in deep minima, and their reactions are not allowed without catalysis. However, when an oriented-external electric field (OEEF) is directed along the B---X---Y reaction axis, the field acts as electric tweezers that orient the XB along the field's axis, and intensely catalyze the process, by tens of kcal/mol, thus rendering the reaction allowed. Flipping the OEEF along the reaction axis inhibits the reaction and weakens the interaction of the XB. Furthermore, at a critical OEEF, each XB undergoes spontaneous and barrier-free reaction. As such, OEEF achieves quite tight control of the structure and reactivity of XB species. Valence bond modeling is used to elucidate the means whereby OEEFs exert their control.
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Affiliation(s)
- Chao Wang
- Institute of Chemistry , The Hebrew University of Jerusalem , Jerusalem 9190407 , Israel.,Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Laboratory of Photochemistry, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry , Chinese Academy of Sciences , Beijing 100190 , P. R. China
| | - David Danovich
- Institute of Chemistry , The Hebrew University of Jerusalem , Jerusalem 9190407 , Israel
| | - Hui Chen
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Laboratory of Photochemistry, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry , Chinese Academy of Sciences , Beijing 100190 , P. R. China
| | - Sason Shaik
- Institute of Chemistry , The Hebrew University of Jerusalem , Jerusalem 9190407 , Israel
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31
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Fung ED, Gelbwaser D, Taylor J, Low J, Xia J, Davydenko I, Campos LM, Marder S, Peskin U, Venkataraman L. Breaking Down Resonance: Nonlinear Transport and the Breakdown of Coherent Tunneling Models in Single Molecule Junctions. NANO LETTERS 2019; 19:2555-2561. [PMID: 30821465 DOI: 10.1021/acs.nanolett.9b00316] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The promise of the field of single-molecule electronics is to reveal a new class of quantum devices that leverages the strong electronic interactions inherent to subnanometer scale systems. Here, we form Au-molecule-Au junctions using a custom scanning tunneling microscope and explore charge transport through current-voltage measurements. We focus on the resonant tunneling regime of two molecules, one that is primarily an electron conductor and one that conducts primarily holes. We find that in the high bias regime, junctions that do not rupture demonstrate reproducible and pronounced negative differential resistance (NDR)-like features followed by hysteresis with peak-to-valley ratios exceeding 100 in some cases. Furthermore, we show that both junction rupture and NDR are induced by charging of the molecular orbital dominating transport and find that the charging is reversible at lower bias and with time with kinetic time scales on the order of hundreds of milliseconds. We argue that these results cannot be explained by existing models of charge transport and likely require theoretical advances describing the transition from coherent to sequential tunneling. Our work also suggests new rules for operating single-molecule devices at high bias to obtain highly nonlinear behavior.
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Affiliation(s)
- E-Dean Fung
- Department of Applied Physics and Applied Mathematics , Columbia University , New York , New York 10027 , United States
| | - David Gelbwaser
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 United States
| | - Jeffrey Taylor
- Department of Applied Physics and Applied Mathematics , Columbia University , New York , New York 10027 , United States
| | - Jonathan Low
- Department of Chemistry , Columbia University , New York , New York 10027 , United States
| | - Jianlong Xia
- School of Chemistry, Chemical Engineering, and Life Science , Wuhan University of Technology , Wuhan 430070 , China
| | - Iryna Davydenko
- School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics , Georgia Institute of Technology , Atlanta , Georgia 30332-0400 , United States
| | - Luis M Campos
- Department of Chemistry , Columbia University , New York , New York 10027 , United States
| | - Seth Marder
- School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics , Georgia Institute of Technology , Atlanta , Georgia 30332-0400 , United States
| | - Uri Peskin
- Schulich Faculty of Chemistry , Technion-Israel Institute of Technology , Haifa 32000 , Israel
| | - Latha Venkataraman
- Department of Applied Physics and Applied Mathematics , Columbia University , New York , New York 10027 , United States
- Department of Chemistry , Columbia University , New York , New York 10027 , United States
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32
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Non-chemisorbed gold-sulfur binding prevails in self-assembled monolayers. Nat Chem 2019; 11:351-358. [PMID: 30833721 DOI: 10.1038/s41557-019-0216-y] [Citation(s) in RCA: 142] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 01/03/2019] [Indexed: 11/09/2022]
Abstract
Gold-thiol contacts are ubiquitous across the physical and biological sciences in connecting organic molecules to surfaces. When thiols bind to gold in self-assembled monolayers (SAMs) the fate of the hydrogen remains a subject of profound debate-with implications for our understanding of their physical properties, spectroscopic features and formation mechanism(s). Exploiting measurements of the transmission through a molecular junction, which is highly sensitive to the nature of the molecule-electrode contact, we demonstrate here that the nature of the gold-sulfur bond in SAMs can be probed via single-molecule conductance measurements. Critically, we find that SAM measurements of dithiol-terminated molecular junctions yield a significantly lower conductance than solution measurements of the same molecule. Through numerous control experiments, conductance noise analysis and transport calculations based on density functional theory, we show that the gold-sulfur bond in SAMs prepared from the solution deposition of dithiols does not have chemisorbed character, which strongly suggests that under these widely used preparation conditions the hydrogen is retained.
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33
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Kosov DS. Waiting time between charging and discharging processes in molecular junctions. J Chem Phys 2018; 149:164105. [PMID: 30384714 DOI: 10.1063/1.5049770] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
When electric current flows through a molecular junction, the molecule constantly charges and discharges by tunneling electrons. These charging and discharging events occur at specific but random times and are separated by stochastic time intervals. These time intervals can be associated with the dwelling time for a charge (electron or hole) to reside on the molecule. In this paper, the statistical properties of these time intervals are studied and a general formula for their distribution is derived. The theory is based on the Markovian master equation which takes into account transitions between the vibrational states of charged and neutral molecules in the junction. Two quantum jump operators are identified from the Liouvillian of the master equation-one corresponds to charging of the molecule and the other discharges the molecule back to the neutral state. The quantum jump operators define the conditional probability that given that the molecule was charged by a tunneling electron at time t, the molecule becomes neutral at a later time t + τ discharging the electron to the drain electrode. Statistical properties of these time intervals τ are studied with the use of this distribution.
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Affiliation(s)
- Daniel S Kosov
- College of Science and Engineering, James Cook University, Townsville, QLD 4811, Australia
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34
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Gelbwaser-Klimovsky D, Aspuru-Guzik A, Thoss M, Peskin U. High-Voltage-Assisted Mechanical Stabilization of Single-Molecule Junctions. NANO LETTERS 2018; 18:4727-4733. [PMID: 29923410 DOI: 10.1021/acs.nanolett.8b01127] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Resonant tunneling is an efficient mechanism for charge transport through nanoscale conductance junctions due to the relatively high currents involved. However, continuous charging and discharging cycles of the nanoconductor during resonant tunneling often lead to mechanical instability. The realization of efficient nanoscale electronic components therefore depends to a large extent on the ability to mechanically stabilize them during resonant transport. In this work, we focus on single-molecule junctions, demonstrating that their mechanical stability during resonant transport can be increased by increasing the bias voltage. This counter-intuitive effect is attributed to the energy dependence of the molecule-lead coupling densities, which promote the rate of transport-induced cooling of molecular vibrations at higher voltages. The required energy dependence is characteristic of realistic electrodes (such as graphene), which cannot be modeled within the commonly invoked wide-band approximation. Our research provides new guidelines for the design of mechanically stable molecular devices operating in the regime of resonant charge transport and demonstrates these guidelines while considering realistic features of single-molecule junctions.
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Affiliation(s)
- David Gelbwaser-Klimovsky
- Department of Chemistry and Chemical Biology , Harvard University , Cambridge , Massachusetts 02138 , United States
| | - Alán Aspuru-Guzik
- Department of Chemistry and Chemical Biology , Harvard University , Cambridge , Massachusetts 02138 , United States
| | - Michael Thoss
- Institute of Physics , University of Freiburg , Hermann-Herder-Strasse 3 , D-79104 Freiburg , Germany
| | - Uri Peskin
- Schulich Faculty of Chemistry , Technion-Israel Institute of Technology , Haifa 32000 , Israel
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35
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Shaik S, Ramanan R, Danovich D, Mandal D. Structure and reactivity/selectivity control by oriented-external electric fields. Chem Soc Rev 2018; 47:5125-5145. [PMID: 29979456 DOI: 10.1039/c8cs00354h] [Citation(s) in RCA: 245] [Impact Index Per Article: 40.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
This is a tutorial on use of external-electric-fields (EEFs) as effectors of chemical change. The tutorial instructs readers how to conceptualize and design electric-field effects on bonds, structures, and reactions. Most effects can be comprehended as the field-induced stabilization of ionic structures. Thus, orienting the field along the "bond axis" will facilitate bond breaking. Similarly, orienting the field along the "reaction axis", the direction in which "electron pairs transform" from reactants- to products-like, will catalyse the reaction. Flipping the field's orientation along the reaction-axis will cause inhibition. Orienting the field off-reaction-axis will control stereo-selectivity and remove forbidden-orbital mixing. Two-directional fields may control both reactivity and selectivity. Increasing the field strength for concerted reactions (e.g., Diels-Alder's) will cause mechanistic-switchover to stepwise mechanisms with ionic intermediates. Examples of bond breaking and control of reactivity/selectivity and mechanisms are presented and analysed from the "ionic perspective". The tutorial projects the unity of EEF effects, "giving insight and numbers".
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Affiliation(s)
- Sason Shaik
- Institute of Chemistry, The Hebrew University of Jerusalem, 91904, Jerusalem, Israel.
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36
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Cai Z, Zhang N, Awais MA, Filatov AS, Yu L. Synthesis of Alternating Donor–Acceptor Ladder‐Type Molecules and Investigation of Their Multiple Charge‐Transfer Pathways. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201713323] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Zhengxu Cai
- Department of Chemistry The University of Chicago 929 E 57th Street Chicago IL 60637 USA
| | - Na Zhang
- Department of Chemistry The University of Chicago 929 E 57th Street Chicago IL 60637 USA
| | - Mohammad A. Awais
- Department of Chemistry The University of Chicago 929 E 57th Street Chicago IL 60637 USA
| | - Alexander S. Filatov
- Department of Chemistry The University of Chicago 929 E 57th Street Chicago IL 60637 USA
| | - Luping Yu
- Department of Chemistry The University of Chicago 929 E 57th Street Chicago IL 60637 USA
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37
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Cai Z, Zhang N, Awais MA, Filatov AS, Yu L. Synthesis of Alternating Donor–Acceptor Ladder‐Type Molecules and Investigation of Their Multiple Charge‐Transfer Pathways. Angew Chem Int Ed Engl 2018; 57:6442-6448. [DOI: 10.1002/anie.201713323] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Indexed: 11/05/2022]
Affiliation(s)
- Zhengxu Cai
- Department of Chemistry The University of Chicago 929 E 57th Street Chicago IL 60637 USA
| | - Na Zhang
- Department of Chemistry The University of Chicago 929 E 57th Street Chicago IL 60637 USA
| | - Mohammad A. Awais
- Department of Chemistry The University of Chicago 929 E 57th Street Chicago IL 60637 USA
| | - Alexander S. Filatov
- Department of Chemistry The University of Chicago 929 E 57th Street Chicago IL 60637 USA
| | - Luping Yu
- Department of Chemistry The University of Chicago 929 E 57th Street Chicago IL 60637 USA
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38
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Li H, Su TA, Camarasa‐Gómez M, Hernangómez‐Pérez D, Henn SE, Pokorný V, Caniglia CD, Inkpen MS, Korytár R, Steigerwald ML, Nuckolls C, Evers F, Venkataraman L. Silver Makes Better Electrical Contacts to Thiol‐Terminated Silanes than Gold. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201708524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Haixing Li
- Department of Applied Physics and Chemistry Columbia University New York NY 10027 USA
| | - Timothy A. Su
- Department of Applied Physics and Chemistry Columbia University New York NY 10027 USA
| | - María Camarasa‐Gómez
- Institute of Theoretical Physics University of Regensburg 93040 Regensburg Germany
| | | | - Simon E. Henn
- Department of Applied Physics and Chemistry Columbia University New York NY 10027 USA
| | - Vladislav Pokorný
- Department of Condensed Matter Physics, Faculty of Math and Physics Charles University Ke Karlovu 5 121 16 Praha 2 Czech Republic
- Institute of Physics The Czech Academy of Sciences Na Slovance 2 18221 Prague 8 Czech Republic
| | | | - Michael S. Inkpen
- Department of Applied Physics and Chemistry Columbia University New York NY 10027 USA
| | - Richard Korytár
- Department of Condensed Matter Physics, Faculty of Math and Physics Charles University Ke Karlovu 5 121 16 Praha 2 Czech Republic
| | | | - Colin Nuckolls
- Department of Applied Physics and Chemistry Columbia University New York NY 10027 USA
| | - Ferdinand Evers
- Institute of Theoretical Physics University of Regensburg 93040 Regensburg Germany
| | - Latha Venkataraman
- Department of Applied Physics and Chemistry Columbia University New York NY 10027 USA
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39
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Li H, Su TA, Camarasa‐Gómez M, Hernangómez‐Pérez D, Henn SE, Pokorný V, Caniglia CD, Inkpen MS, Korytár R, Steigerwald ML, Nuckolls C, Evers F, Venkataraman L. Silver Makes Better Electrical Contacts to Thiol‐Terminated Silanes than Gold. Angew Chem Int Ed Engl 2017; 56:14145-14148. [DOI: 10.1002/anie.201708524] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Indexed: 11/09/2022]
Affiliation(s)
- Haixing Li
- Department of Applied Physics and Chemistry Columbia University New York NY 10027 USA
| | - Timothy A. Su
- Department of Applied Physics and Chemistry Columbia University New York NY 10027 USA
| | - María Camarasa‐Gómez
- Institute of Theoretical Physics University of Regensburg 93040 Regensburg Germany
| | | | - Simon E. Henn
- Department of Applied Physics and Chemistry Columbia University New York NY 10027 USA
| | - Vladislav Pokorný
- Department of Condensed Matter Physics, Faculty of Math and Physics Charles University Ke Karlovu 5 121 16 Praha 2 Czech Republic
- Institute of Physics The Czech Academy of Sciences Na Slovance 2 18221 Prague 8 Czech Republic
| | | | - Michael S. Inkpen
- Department of Applied Physics and Chemistry Columbia University New York NY 10027 USA
| | - Richard Korytár
- Department of Condensed Matter Physics, Faculty of Math and Physics Charles University Ke Karlovu 5 121 16 Praha 2 Czech Republic
| | | | - Colin Nuckolls
- Department of Applied Physics and Chemistry Columbia University New York NY 10027 USA
| | - Ferdinand Evers
- Institute of Theoretical Physics University of Regensburg 93040 Regensburg Germany
| | - Latha Venkataraman
- Department of Applied Physics and Chemistry Columbia University New York NY 10027 USA
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40
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Wang M, Wang Y, Sanvito S, Hou S. The low-bias conducting mechanism of single-molecule junctions constructed with methylsulfide linker groups and gold electrodes. J Chem Phys 2017; 147:054702. [PMID: 28789544 DOI: 10.1063/1.4996745] [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)
- Minglang Wang
- Key Laboratory for the Physics and Chemistry of Nanodevices, Department of Electronics, Peking University, Beijing 100871, China
| | - Yongfeng Wang
- Key Laboratory for the Physics and Chemistry of Nanodevices, Department of Electronics, Peking University, Beijing 100871, China
- Beida Information Research (BIR), Tianjin 300457, China
| | - Stefano Sanvito
- School of Physics, AMBER and CRANN Institute, Trinity College, Dublin 2, Ireland
| | - Shimin Hou
- Key Laboratory for the Physics and Chemistry of Nanodevices, Department of Electronics, Peking University, Beijing 100871, China
- Beida Information Research (BIR), Tianjin 300457, China
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41
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Su TA, Li H, Klausen RS, Kim NT, Neupane M, Leighton JL, Steigerwald ML, Venkataraman L, Nuckolls C. Silane and Germane Molecular Electronics. Acc Chem Res 2017; 50:1088-1095. [PMID: 28345881 DOI: 10.1021/acs.accounts.7b00059] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
This Account provides an overview of our recent efforts to uncover the fundamental charge transport properties of Si-Si and Ge-Ge single bonds and introduce useful functions into group 14 molecular wires. We utilize the tools of chemical synthesis and a scanning tunneling microscopy-based break-junction technique to study the mechanism of charge transport in these molecular systems. We evaluated the fundamental ability of silicon, germanium, and carbon molecular wires to transport charge by comparing conductances within families of well-defined structures, the members of which differ only in the number of Si (or Ge or C) atoms in the wire. For each family, this procedure yielded a length-dependent conductance decay parameter, β. Comparison of the different β values demonstrates that Si-Si and Ge-Ge σ bonds are more conductive than the analogous C-C σ bonds. These molecular trends mirror what is seen in the bulk. The conductance decay of Si and Ge-based wires is similar in magnitude to those from π-based molecular wires such as paraphenylenes However, the chemistry of the linkers that attach the molecular wires to the electrodes has a large influence on the resulting β value. For example, Si- and Ge-based wires of many different lengths connected with a methyl-thiomethyl linker give β values of 0.36-0.39 Å-1, whereas Si- and Ge-based wires connected with aryl-thiomethyl groups give drastically different β values for short and long wires. This observation inspired us to study molecular wires that are composed of both π- and σ-orbitals. The sequence and composition of group 14 atoms in the σ chain modulates the electronic coupling between the π end-groups and dictates the molecular conductance. The conductance behavior originates from the coupling between the subunits, which can be understood by considering periodic trends such as bond length, polarizability, and bond polarity. We found that the same periodic trends determine the electric field-induced breakdown properties of individual Si-Si, Ge-Ge, Si-O, Si-C, and C-C bonds. Building from these studies, we have prepared a system that has two different, alternative conductance pathways. In this wire, we can intentionally break a labile, strained silicon-silicon bond and thereby shunt the current through the secondary conduction pathway. This type of in situ bond-rupture provides a new tool to study single molecule reactions that are induced by electric fields. Moreover, these studies provide guidance for designing dielectric materials as well as molecular devices that require stability under high voltage bias. The fundamental studies on the structure/function relationships of the molecular wires have guided the design of new functional systems based on the Si- and Ge-based wires. For example, we exploited the principle of strain-induced Lewis acidity from reaction chemistry to design a single molecule switch that can be controllably switched between two conductive states by varying the distance between the tip and substrate electrodes. We found that the strain intrinsic to the disilaacenaphthene scaffold also creates two state conductance switching. Finally, we demonstrate the first example of a stereoelectronic conductance switch, and we demonstrate that the switching relies crucially on the electronic delocalization in Si-Si and Ge-Ge wire backbones. These studies illustrate the untapped potential in using Si- and Ge-based wires to design and control charge transport at the nanoscale and to allow quantum mechanics to be used as a tool to design ultraminiaturized switches.
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Affiliation(s)
- Timothy A. Su
- Columbia University, Department of Chemistry, New York, New York 10027, United States
| | - Haixing Li
- Columbia University, Department of Applied Physics
and Applied Math, New York, New York 10027, United States
| | - Rebekka S. Klausen
- Johns Hopkins University, Department of Chemistry, Baltimore, Maryland 21228, United States
| | - Nathaniel T. Kim
- Columbia University, Department of Chemistry, New York, New York 10027, United States
| | - Madhav Neupane
- Columbia University, Department of Chemistry, New York, New York 10027, United States
| | - James L. Leighton
- Columbia University, Department of Chemistry, New York, New York 10027, United States
| | | | - Latha Venkataraman
- Columbia University, Department of Chemistry, New York, New York 10027, United States
- Columbia University, Department of Applied Physics
and Applied Math, New York, New York 10027, United States
| | - Colin Nuckolls
- Columbia University, Department of Chemistry, New York, New York 10027, United States
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42
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Friedman HM, Agarwalla BK, Segal D. Effects of vibrational anharmonicity on molecular electronic conduction and thermoelectric efficiency. J Chem Phys 2017. [DOI: 10.1063/1.4965824] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Hava Meira Friedman
- Chemical Physics Theory Group, Department of Chemistry, and Centre for Quantum Information and Quantum Control, University of Toronto, 80 Saint George St., Toronto, Ontario M5S 3H6, Canada
| | - Bijay Kumar Agarwalla
- Chemical Physics Theory Group, Department of Chemistry, and Centre for Quantum Information and Quantum Control, University of Toronto, 80 Saint George St., Toronto, Ontario M5S 3H6, Canada
| | - Dvira Segal
- Chemical Physics Theory Group, Department of Chemistry, and Centre for Quantum Information and Quantum Control, University of Toronto, 80 Saint George St., Toronto, Ontario M5S 3H6, Canada
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43
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Direct mapping of electrical noise sources in molecular wire-based devices. Sci Rep 2017; 7:43411. [PMID: 28233821 PMCID: PMC5324066 DOI: 10.1038/srep43411] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 01/24/2017] [Indexed: 11/09/2022] Open
Abstract
We report a noise mapping strategy for the reliable identification and analysis of noise sources in molecular wire junctions. Here, different molecular wires were patterned on a gold substrate, and the current-noise map on the pattern was measured and analyzed, enabling the quantitative study of noise sources in the patterned molecular wires. The frequency spectra of the noise from the molecular wire junctions exhibited characteristic 1/f2 behavior, which was used to identify the electrical signals from molecular wires. This method was applied to analyze the molecular junctions comprising various thiol molecules on a gold substrate, revealing that the noise in the junctions mainly came from the fluctuation of the thiol bonds. Furthermore, we quantitatively compared the frequencies of such bond fluctuations in different molecular wire junctions and identified molecular wires with lower electrical noise, which can provide critical information for designing low-noise molecular electronic devices. Our method provides valuable insights regarding noise phenomena in molecular wires and can be a powerful tool for the development of molecular electronic devices.
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44
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Arnold D, Marz M, Schneider S, Hoffmann-Vogel R. Structure and local charging of electromigrated Au nanocontacts. NANOTECHNOLOGY 2017; 28:055206. [PMID: 28032610 DOI: 10.1088/1361-6528/28/5/055206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We study the structure and the electronic properties of Au nanocontacts created by controlled electromigration of thin film devices, a method frequently used to contact molecules. In contrast to electromigration testing, a current is applied in a cyclic fashion and during each cycle the resistance increase of the metal upon heating is used to avoid thermal runaway. In this way, nanometer sized-gaps are obtained. The thin film devices with an optimized structure at the origin of the electromigration process are made by shadow evaporation without contamination by organic materials. Defining rounded edges and a thinner area in the center of the device allow to pre-determine the location where the electromigration takes place. Scanning force microscopy images of the pristine Au film and electromigrated contact show its grainy structure. Through electromigration, a 1.5 μm-wide slit is formed, with extensions only on the anode side that had previously not been observed in narrower structures. It is discussed whether this could be explained by asymmetric heating of both electrodes. New grains are formed in the slit and on the extensions on both, the anode and the cathode side. The smaller structures inside the slit lead to an electrode distance below 150 nm. Kelvin probe force microscopy images show a local work function difference with fluctuations of 70 mV on the metal before electromigration. Between the electrodes, disconnected through electromigration, a work function difference of 3.2 V is observed due to charging. Some of the grains newly formed by electromigration are electrically disconnected from the electrodes.
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Affiliation(s)
- D Arnold
- Physikalisches Institut, Karlsruhe Institute of Technology (KIT), D-76131 Karlsruhe, Germany
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45
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Wang K, Xu B. Modulation and Control of Charge Transport Through Single-Molecule Junctions. Top Curr Chem (Cham) 2017; 375:17. [PMID: 28120303 DOI: 10.1007/s41061-017-0105-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 01/07/2017] [Indexed: 11/26/2022]
Abstract
The ability to modulate and control charge transport though single-molecule junction devices is crucial to achieving the ultimate goal of molecular electronics: constructing real-world-applicable electronic components from single molecules. This review aims to highlight the progress made in single-molecule electronics, emphasizing the development of molecular junction electronics in recent years. Among many techniques that attempt to wire a molecule to metallic electrodes, the single-molecule break junction (SMBJ) technique is one of the most reliable and tunable experimental platforms for achieving metal-molecule-metal configurations. It also provides great freedom to tune charge transport through the junction. Soon after the SMBJ technique was introduced, it was extensively used to measure the conductances of individual molecules; however, different conductances were obtained for the same molecule, and it proved difficult to interpret this wide distribution of experimental data. This phenomenon was later found to be mainly due to a lack of precise experimental control and advanced data analysis methods. In recent years, researchers have directed considerable effort into advancing the SMBJ technique by gaining a deeper physical understanding of charge transport through single molecules and thus enhancing its potential applicability in functional molecular-scale electronic devices, such as molecular diodes and molecular transistors. In parallel with that research, novel data analysis methods and approaches that enable the discovery of hidden yet important features in the data are being developed. This review discusses various aspects of molecular junction electronics, from the initial goal of molecular electronics, the development of experimental techniques for creating single-molecule junctions and determining single-molecule conductance, to the characterization of functional current-voltage features and the investigation of physical properties other than charge transport. In addition, the development of advanced data analysis methods is considered, as they are critical to gaining detailed physical insight into the underlying transport mechanisms.
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Affiliation(s)
- Kun Wang
- Department of Physics and Astronomy and NanoSEC, University of Georgia, 220 Riverbend Road, Athens, GA, 30602, USA
| | - Bingqian Xu
- College of Engineering and NanoSEC, University of Georgia, 220 Riverbend Road, Athens, GA, 30602, USA.
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46
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Li H, Kim NT, Su TA, Steigerwald ML, Nuckolls C, Darancet P, Leighton JL, Venkataraman L. Mechanism for Si–Si Bond Rupture in Single Molecule Junctions. J Am Chem Soc 2016; 138:16159-16164. [DOI: 10.1021/jacs.6b10700] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Haixing Li
- Department
of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United States
| | - Nathaniel T. Kim
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
| | - Timothy A. Su
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
| | | | - Colin Nuckolls
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
| | - Pierre Darancet
- Center
for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - James L. Leighton
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
| | - Latha Venkataraman
- Department
of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United States
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
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47
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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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48
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Kilgour M, Segal D. Inelastic effects in molecular transport junctions: The probe technique at high bias. J Chem Phys 2016; 144:124107. [DOI: 10.1063/1.4944470] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Michael Kilgour
- Chemical Physics Theory Group, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Dvira Segal
- Chemical Physics Theory Group, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
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49
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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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