1
|
Li N, Yuan X, Li Y, Zhang G, Yang Q, Zhou Y, Guo M, Liu J. Bioinspired Liquid Metal Based Soft Humanoid Robots. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2404330. [PMID: 38723269 DOI: 10.1002/adma.202404330] [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: 03/25/2024] [Revised: 05/07/2024] [Indexed: 08/29/2024]
Abstract
The pursuit of constructing humanoid robots to replicate the anatomical structures and capabilities of human beings has been a long-standing significant undertaking and especially garnered tremendous attention in recent years. However, despite the progress made over recent decades, humanoid robots have predominantly been confined to those rigid metallic structures, which however starkly contrast with the inherent flexibility observed in biological systems. To better innovate this area, the present work systematically explores the value and potential of liquid metals and their derivatives in facilitating a crucial transition towards soft humanoid robots. Through a comprehensive interpretation of bionics, an overview of liquid metals' multifaceted roles as essential components in constructing advanced humanoid robots-functioning as soft actuators, sensors, power sources, logical devices, circuit systems, and even transformable skeletal structures-is presented. It is conceived that the integration of these components with flexible structures, facilitated by the unique properties of liquid metals, can create unexpected versatile functionalities and behaviors to better fulfill human needs. Finally, a revolution in humanoid robots is envisioned, transitioning from metallic frameworks to hybrid soft-rigid structures resembling that of biological tissues. This study is expected to provide fundamental guidance for the coming research, thereby advancing the area.
Collapse
Affiliation(s)
- Nan Li
- State Key Laboratory of Cryogenic Science and Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- School of Future Technology, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaohong Yuan
- School of Economics and Business Administration, Chongqing University, Chongqing, 400044, China
| | - Yuqing Li
- State Key Laboratory of Cryogenic Science and Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- School of Future Technology, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Guangcheng Zhang
- State Key Laboratory of Cryogenic Science and Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- School of Future Technology, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Qianhong Yang
- State Key Laboratory of Cryogenic Science and Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- School of Future Technology, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yingxin Zhou
- State Key Laboratory of Cryogenic Science and Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- School of Future Technology, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Minghui Guo
- State Key Laboratory of Cryogenic Science and Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Jing Liu
- State Key Laboratory of Cryogenic Science and Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- School of Future Technology, University of Chinese Academy of Sciences, Beijing, 100049, China
- School of Biomedical Engineering, Tsinghua University, Beijing, 100084, China
| |
Collapse
|
2
|
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.
Collapse
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
| |
Collapse
|
3
|
Cao N, Bro-Jørgensen W, Zheng X, Solomon GC. Visualizing and comparing quantum interference in the π-system and σ-system of organic molecules. J Chem Phys 2023; 158:124305. [PMID: 37003722 DOI: 10.1063/5.0141577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023] Open
Abstract
Quantum interference effects in conjugated molecules have been well-explored, with benzene frequently invoked as a pedagogical example. These interference effects have been understood through a quantum interference map in which the electronic transmission is separated into interfering and non-interfering terms, with a focus on the π-orbitals for conjugated molecules. Recently, saturated molecules have also been reported to exhibit destructive quantum interference effects; however, the very different σ-orbital character in these molecules means that it is not clear how orbital contributions manifest. Herein, we demonstrate that the quantum interference effects in conjugated molecules are quite different from those observed in saturated molecules, as demonstrated by the quantum interference map. While destructive interference at the Fermi energy in the π-system of benzene arises from interference terms between paired occupied and virtual orbitals, this is not the case at the Fermi energy in saturated systems. Instead, destructive interference is evident when contributions from a larger number of non-paired orbitals cancel, leading to more subtle and varied manifestations of destructive interference in saturated systems.
Collapse
Affiliation(s)
- Ning Cao
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
| | - William Bro-Jørgensen
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
| | - Xiaohong Zheng
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
| | - Gemma C Solomon
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
| |
Collapse
|
4
|
Trasobares J, Martín-Romano JC, Khaliq MW, Ruiz-Gómez S, Foerster M, Niño MÁ, Pedraz P, Dappe YJ, de Ory MC, García-Pérez J, Acebrón M, Osorio MR, Magaz MT, Gomez A, Miranda R, Granados D. Hybrid molecular graphene transistor as an operando and optoelectronic platform. Nat Commun 2023; 14:1381. [PMID: 36914623 PMCID: PMC10011542 DOI: 10.1038/s41467-023-36714-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 02/13/2023] [Indexed: 03/16/2023] Open
Abstract
Lack of reproducibility hampers molecular devices integration into large-scale circuits. Thus, incorporating operando characterization can facilitate the understanding of multiple features producing disparities in different devices. In this work, we report the realization of hybrid molecular graphene field effect transistors (m-GFETs) based on 11-(Ferrocenyl)undecanethiol (FcC11SH) micro self-assembled monolayers (μSAMs) and high-quality graphene (Gr) in a back-gated configuration. On the one hand, Gr enables redox electron transfer, avoids molecular degradation and permits operando spectroscopy. On the other hand, molecular electrode decoration shifts the Gr Dirac point (VDP) to neutrality and generates a photocurrent in the Gr electron conduction regime. Benefitting from this heterogeneous response, the m-GFETs can implement optoelectronic AND/OR logic functions. Our approach represents a step forward in the field of molecular scale electronics with implications in sensing and computing based on sustainable chemicals.
Collapse
Affiliation(s)
- Jorge Trasobares
- IMDEA-Nanociencia, Cantoblanco, Madrid, 28049, Spain. .,Department of Biodiversity, Ecology and Evolution (Biomathematics), Universidad Complutense de Madrid, Madrid, 28040, Spain.
| | | | - Muhammad Waqas Khaliq
- ALBA Synchrotron, Carrer de la llum 2-26, Cerdanyola del Valles, 08290, Spain.,Department of Condensed Matter Physics, University of Barcelona, Barcelona, Spain
| | - Sandra Ruiz-Gómez
- ALBA Synchrotron, Carrer de la llum 2-26, Cerdanyola del Valles, 08290, Spain
| | - Michael Foerster
- ALBA Synchrotron, Carrer de la llum 2-26, Cerdanyola del Valles, 08290, Spain
| | - Miguel Ángel Niño
- ALBA Synchrotron, Carrer de la llum 2-26, Cerdanyola del Valles, 08290, Spain
| | | | - Yannick J Dappe
- Centro de Astrobiología (CSIC-INTA), Torrejón de Ardoz, 28850, Spain
| | | | | | - María Acebrón
- IMDEA-Nanociencia, Cantoblanco, Madrid, 28049, Spain
| | | | | | - Alicia Gomez
- Centro de Astrobiología (CSIC-INTA), Torrejón de Ardoz, 28850, Spain
| | - Rodolfo Miranda
- SPEC, CEA, CNRS Université Paris-Saclay, Gif-sur-Yvette, 91191, France.,Dpto. de Física de la Materia Condensada, Universidad Autónoma de Madrid, Cantoblanco, Spain
| | | |
Collapse
|
5
|
Zhou P, Qiao X, Milan DC, Higgins SJ, Vezzoli A, Nichols RJ. Enhanced charge transport across molecule-nanoparticle-molecule sandwiches. Phys Chem Chem Phys 2023; 25:7176-7183. [PMID: 36810584 DOI: 10.1039/d2cp05525b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
The electrical properties of large area molecular devices consisting of gold nanoparticles (GNPs) sandwiched between a double layer of alkanedithiol linkers have been examined. These devices have been fabricated by a facile bottom-up assembly in which an alkanedithiol monolayer is first self-assembled on an underlying gold substrate followed by nanoparticle adsorption and then finally assembly of the top alkanedithiol layer. These devices are then sandwiched between the bottom gold substrates and a top eGaIn probe contact and current-voltage (I-V) curves recorded. Devices have been fabricated with 1,5-pentanedithiol, 1,6-hexanedithiol, 1,8-octanedithiol and 1,10-decanedithiol linkers. In all cases the electrical conductance of the double SAM junctions with GNPs is higher than the corresponding and much thinner single alkanedithiol SAM. Competing models for this enhanced conductance are discussed and it is suggested to have a topological origin arising from how the devices assemble or structure during the fabrication, which gives more efficient cross device electron transport pathways without the GNPs producing short circuits.
Collapse
Affiliation(s)
- P Zhou
- Yangzhou Polytechnic Institute, No. 199, Huayang West Road, Yangzhou City, Jiangsu Province, China.,Department of Chemistry, University of Liverpool, Crown St, Liverpool, L69 7ZD, UK.
| | - X Qiao
- Department of Chemistry, University of Liverpool, Crown St, Liverpool, L69 7ZD, UK.
| | - D C Milan
- Department of Chemistry, University of Liverpool, Crown St, Liverpool, L69 7ZD, UK.
| | - S J Higgins
- Department of Chemistry, University of Liverpool, Crown St, Liverpool, L69 7ZD, UK.
| | - A Vezzoli
- Department of Chemistry, University of Liverpool, Crown St, Liverpool, L69 7ZD, UK.
| | - R J Nichols
- Department of Chemistry, University of Liverpool, Crown St, Liverpool, L69 7ZD, UK.
| |
Collapse
|
6
|
Li Y, Root SE, Belding L, Park J, Yoon HJ, Huang C, Baghbanzadeh M, Whitesides GM. Charge Transport Measured Using the EGaIn Junction through Self-Assembled Monolayers Immersed in Organic Liquids. J Phys Chem B 2023; 127:407-424. [PMID: 36580625 DOI: 10.1021/acs.jpcb.2c07901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
This paper describes measurements of charge transport by tunneling through molecular junctions comprising a self-assembled monolayer (SAM) supported by a template-stripped metal bottom electrode (MTS), which has been immersed in an organic liquid and contacted by a conical Ga2O3/EGaIn top electrode. These junctions formed in organic liquids are robust; they show stabilities and yields similar to those formed in air. We formed junctions under seven external environments: (I) air, (II) perfluorocarbons, (III) linear hydrocarbons, (IV) cyclic hydrocarbons, (V) aromatic compounds, (VI) large, irregularly shaped hydrocarbons, and (VII) dimethyl siloxanes. Several different lengths of SAMs of n-alkanethiolates, S(CH2)n-1CH3 with n = 4-18, and two different kinds of bottom electrodes (AgTS or AuTS) are employed to assess the mechanism underlying the observed changes in tunneling currents. Measurements of current density through junctions immersed in perfluorocarbons (II) are comparable to junctions measured in air. Junctions immersed in other organic liquids show reductions in the values of current density, compared to the values in air, ranging from 1 (III) to 5 orders of magnitude (IV). We interpret the most plausible mechanism for these reductions in current densities to be an increase in the length of the tunneling pathway, reflecting the formation of thin (0.5-1.5 nm) liquid films at the interface between the SAM and the Ga2O3/EGaIn electrode. Remarkably, the thickness of the liquid film─estimated by the simplified Simmons model, measurements of electrical breakdown of the junction, and simulations of molecular dynamics─is consistent with the existing observations of structured liquid layers that form between two flat interfaces from measurements obtained by the surface force apparatus. These results suggest the use of the EGaIn junction and measurements of charge transport by tunneling as a new form of surface analysis, with the applications in the study of near-surface, weak, molecular interactions and the behavior of liquid films adjacent to non-polar interfaces.
Collapse
Affiliation(s)
- Yuan Li
- Department of Chemistry, Tsinghua University, Beijing100086, China.,Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts02138, United States
| | - Samuel E Root
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts02138, United States
| | - Lee Belding
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts02138, United States
| | - Junwoo Park
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts02138, United States.,Department of Chemistry, Sogang University, Seoul04107, Korea
| | - Hyo Jae Yoon
- Department of Chemistry, Korea University, Seoul02841, Korea
| | - Cancan Huang
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts02138, United States
| | - Mostafa Baghbanzadeh
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts02138, United States
| | - George M Whitesides
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts02138, United States
| |
Collapse
|
7
|
Zhao Z, Soni S, Lee T, Nijhuis CA, Xiang D. Smart Eutectic Gallium-Indium: From Properties to Applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2203391. [PMID: 36036771 DOI: 10.1002/adma.202203391] [Citation(s) in RCA: 36] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 07/30/2022] [Indexed: 05/27/2023]
Abstract
Eutectic gallium-indium (EGaIn), a liquid metal with a melting point close to or below room temperature, has attracted extensive attention in recent years due to its excellent properties such as fluidity, high conductivity, thermal conductivity, stretchability, self-healing capability, biocompatibility, and recyclability. These features of EGaIn can be adjusted by changing the experimental condition, and various composite materials with extended properties can be further obtained by mixing EGaIn with other materials. In this review, not only the are unique properties of EGaIn introduced, but also the working principles for the EGaIn-based devices are illustrated and the developments of EGaIn-related techniques are summarized. The applications of EGaIn in various fields, such as flexible electronics (sensors, antennas, electronic circuits), molecular electronics (molecular memory, opto-electronic switches, or reconfigurable junctions), energy catalysis (heat management, motors, generators, batteries), biomedical science (drug delivery, tumor therapy, bioimaging and neural interfaces) are reviewed. Finally, a critical discussion of the main challenges for the development of EGaIn-based techniques are discussed, and the potential applications in new fields are prospected.
Collapse
Affiliation(s)
- Zhibin Zhao
- Institute of Modern Optics and Center of Single Molecule Sciences, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Nankai University, 300350, Tianjin, P. R. China
| | - Saurabh Soni
- Department of Molecules and Materials, MESA+ Institute for Nanotechnology, Molecules Center and Center for Brain-Inspired Nano Systems, Faculty of Science and Technology, University of Twente, Enschede, 7500 AE, The Netherlands
| | - Takhee Lee
- Department of Physics and Astronomy, Institute of Applied Physics, Seoul National University, Seoul, 08826, Korea
| | - Christian A Nijhuis
- Department of Molecules and Materials, MESA+ Institute for Nanotechnology, Molecules Center and Center for Brain-Inspired Nano Systems, Faculty of Science and Technology, University of Twente, Enschede, 7500 AE, The Netherlands
| | - Dong Xiang
- Institute of Modern Optics and Center of Single Molecule Sciences, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Nankai University, 300350, Tianjin, P. R. China
| |
Collapse
|
8
|
Alshammari M, Al-Jobory AA, Alotaibi T, Lambert CJ, Ismael A. Orientational control of molecular scale thermoelectricity. NANOSCALE ADVANCES 2022; 4:4635-4638. [PMID: 36341305 PMCID: PMC9595198 DOI: 10.1039/d2na00515h] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 10/03/2022] [Indexed: 06/13/2023]
Abstract
Through a comprehensive theoretical study, we demonstrate that single-molecule junctions formed from asymmetric molecules with different terminal groups can exhibit Seebeck coefficients, whose sign depends on the orientation of the molecule within the junction. Three anthracene-based molecules are studied, one of which exhibits this bi-thermoelectric behaviour, due to the presence of a thioacetate terminal group at one end and a pyridyl terminal group at the other. A pre-requisite for obtaining this behaviour is the use of junction electrodes formed from different materials. In our case, we use gold as the bottom electrode and graphene-coated gold as the top electrode. This demonstration of bi-thermoelecricity means that if molecules with alternating orientations can be deposited on a substrate, then they form a basis for boosting the thermovoltage in molecular-scale thermoelectric energy generators (TEGs).
Collapse
Affiliation(s)
- Majed Alshammari
- Physics Department, Lancaster University Lancaster LA1 4YB UK
- Department of Physics, College of Science, Jouf University Sakaka Saudi Arabia
| | - Alaa A Al-Jobory
- Physics Department, Lancaster University Lancaster LA1 4YB UK
- Department of Physics, College of Science, University of Anbar Anbar Iraq
| | - Turki Alotaibi
- Physics Department, Lancaster University Lancaster LA1 4YB UK
- Department of Physics, College of Science, Jouf University Sakaka Saudi Arabia
| | - Colin J Lambert
- Physics Department, Lancaster University Lancaster LA1 4YB UK
| | - Ali Ismael
- Physics Department, Lancaster University Lancaster LA1 4YB UK
- Department of Physics, College of Education for Pure Science, Tikrit University Tikrit Iraq
| |
Collapse
|
9
|
Tong Y, Alsalama M, Berdiyorov GR, Hamoudi H. A combined experimental and computational study of the effect of electron irradiation on the transport properties of aromatic and aliphatic molecular self-assemblies. NANOSCALE ADVANCES 2022; 4:3745-3755. [PMID: 36133338 PMCID: PMC9470021 DOI: 10.1039/d2na00040g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 07/13/2022] [Indexed: 06/16/2023]
Abstract
Intermolecular cross-linking through electron irradiation is proven to be an effective tool to improve the mechanical and electronic properties of molecular self-assembled monolayers (SAMs), which is known to be a key player for material nanoarchitectonics. Here we study the effect of electron irradiation on the electronic transport properties of aromatic 5,5'-bis(mercaptomethyl)-2,2'-bipyridine (BPD; HS-CH2-(C5H3N)2-CH2-SH) and electron saturated 1-dodecanethiol (C12; CH3-(CH2)11-SH) molecules self-assembled on an Au (111) surface. We could not create any successful junctions for transport measurements for the electron irradiated C12 SAMs due the deterioration of such molecules with electron saturated nature. For the aromatic molecules, the electron bombardment results in significant reduction of the current despite the electron irradiation-induced intermolecular cross-linking, which should create extra transport channels for charge carriers. The current rectification also reduces after the electron bombardment. In order to interpret the experimental results and give right diagnostics behind the decrease of the current through the junction after electron irradiation, we supplement the experiment with quantum transport calculations using Green's functional formalism in combination with density functional theory. The simulation results show that the reduced current after electron irradiation can be related to the detachment of the molecules from the gold substrate and reattachment to other molecules. The formation of diamond-like structures due to intermolecular-cross linking can also be the reason for the reduced current obtained in the experiments. We have also considered the case when the BPD molecules get broken-conjugated due to the attachment of extra hydrogen atoms to the carbon backbone of the molecule. This structural modification also results in a significant decrease of the current. These findings can be useful in understanding the processes during the electron irradiation of molecular SAMs.
Collapse
Affiliation(s)
- Y Tong
- Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University Doha Qatar
| | - M Alsalama
- Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University Doha Qatar
| | - G R Berdiyorov
- Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University Doha Qatar
| | - H Hamoudi
- Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University Doha Qatar
| |
Collapse
|
10
|
Bennett TLR, Alshammari M, Au-Yong S, Almutlg A, Wang X, Wilkinson LA, Albrecht T, Jarvis SP, Cohen LF, Ismael A, Lambert CJ, Robinson BJ, Long NJ. Multi-component self-assembled molecular-electronic films: towards new high-performance thermoelectric systems. Chem Sci 2022; 13:5176-5185. [PMID: 35655580 PMCID: PMC9093172 DOI: 10.1039/d2sc00078d] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 04/14/2022] [Indexed: 12/02/2022] Open
Abstract
The thermoelectric properties of parallel arrays of organic molecules on a surface offer the potential for large-area, flexible, solution processed, energy harvesting thin-films, whose room-temperature transport properties are controlled by quantum interference (QI). Recently, it has been demonstrated that constructive QI (CQI) can be translated from single molecules to self-assembled monolayers (SAMs), boosting both electrical conductivities and Seebeck coefficients. However, these CQI-enhanced systems are limited by rigid coupling of the component molecules to metallic electrodes, preventing the introduction of additional layers which would be advantageous for their further development. These rigid couplings also limit our ability to suppress the transport of phonons through these systems, which could act to boost their thermoelectric output, without comprising on their impressive electronic features. Here, through a combined experimental and theoretical study, we show that cross-plane thermoelectricity in SAMs can be enhanced by incorporating extra molecular layers. We utilize a bottom-up approach to assemble multi-component thin-films that combine a rigid, highly conductive 'sticky'-linker, formed from alkynyl-functionalised anthracenes, and a 'slippery'-linker consisting of a functionalized metalloporphyrin. Starting from an anthracene-based SAM, we demonstrate that subsequent addition of either a porphyrin layer or a graphene layer increases the Seebeck coefficient, and addition of both porphyrin and graphene leads to a further boost in their Seebeck coefficients. This demonstration of Seebeck-enhanced multi-component SAMs is the first of its kind and presents a new strategy towards the design of thin-film thermoelectric materials.
Collapse
Affiliation(s)
- Troy L R Bennett
- Department of Chemistry, Imperial College London, MSRH White City London W12 0BZ UK
| | - Majed Alshammari
- Physics Department, Lancaster University Lancaster LA1 4YB UK
- Department of Physics, College of Science, Jouf University Skaka Saudi Arabia
| | - Sophie Au-Yong
- Physics Department, Lancaster University Lancaster LA1 4YB UK
| | - Ahmad Almutlg
- Physics Department, Lancaster University Lancaster LA1 4YB UK
- Department of Mathematics, College of Science, Qassim University Almethnab Saudi Arabia
| | - Xintai Wang
- Physics Department, Lancaster University Lancaster LA1 4YB UK
- The Blackett Laboratory, Imperial College London, South Kensington Campus London SW7 2AZ UK
| | - Luke A Wilkinson
- Department of Chemistry, University of York Heslington York YO10 5DD UK
| | - Tim Albrecht
- Department of Chemistry, Birmingham University Edgbaston Birmingham B15 2TT UK
| | - Samuel P Jarvis
- Physics Department, Lancaster University Lancaster LA1 4YB UK
| | - Lesley F Cohen
- The Blackett Laboratory, Imperial College London, South Kensington Campus London SW7 2AZ UK
| | - Ali Ismael
- Physics Department, Lancaster University Lancaster LA1 4YB UK
- Department of Physics, College of Education for Pure Science, Tikrit University Tikrit Iraq
| | - Colin J Lambert
- Physics Department, Lancaster University Lancaster LA1 4YB UK
| | | | - Nicholas J Long
- Department of Chemistry, Imperial College London, MSRH White City London W12 0BZ UK
| |
Collapse
|
11
|
O'Driscoll LJ, Bryce MR. A review of oligo(arylene ethynylene) derivatives in molecular junctions. NANOSCALE 2021; 13:10668-10711. [PMID: 34110337 DOI: 10.1039/d1nr02023d] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Oligo(arylene ethynylene) (OAE) derivatives are the "workhorse" molecules of molecular electronics. Their ease of synthesis and flexibility of functionalisation mean that a diverse array of OAE molecular wires have been designed, synthesised and studied theoretically and experimentally in molecular junctions using both single-molecule and ensemble methods. This review summarises the breadth of molecular designs that have been investigated with emphasis on structure-property relationships with respect to the electronic conductance of OAEs. The factors considered include molecular length, connectivity, conjugation, (anti)aromaticity, heteroatom effects and quantum interference (QI). Growing interest in the thermoelectric properties of OAE derivatives, which are expected to be at the forefront of research into organic thermoelectric devices, is also explored.
Collapse
Affiliation(s)
- Luke J O'Driscoll
- Department of Chemistry, Durham University, Lower Mountjoy, Stockton Road, Durham, UKDH1 3LE.
| | - Martin R Bryce
- Department of Chemistry, Durham University, Lower Mountjoy, Stockton Road, Durham, UKDH1 3LE.
| |
Collapse
|
12
|
Arasu NP, Vázquez H. Origin of the Electron Transport Properties of Aromatic and Antiaromatic Single Molecule Circuits. Chemphyschem 2021; 22:864-869. [PMID: 33656792 DOI: 10.1002/cphc.202100010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 02/12/2021] [Indexed: 11/10/2022]
Abstract
Antiaromatic molecules have been predicted to exhibit increased electron transport properties when placed between two nanoelectrodes compared to their aromatic analogues. While some studies have demonstrated this relationship, others have found no substantial increase. We use atomistic simulations to establish a general relationship between the electronic spectra of aromatic, antiaromatic, and quinoidal molecules and illustrate its implications for electron transport. We compare the electronic properties of a series of aromatic-antiaromatic counterparts and show that antiaromaticity effectively p-dopes the aromatic electronic spectra. As a consequence, the conducting properties of aromatic-antiaromatic analogues are closely related. For similar attachment points to the electrodes, an interference feature is expected in the HOMO-LUMO gap of one whenever it is absent in the other one. We demonstrate how the relative conductance of aromatic-antiaromatic pairs can be tuned and even reversed through the choice of chemical linker groups. Our work provides a general picture relating connectivity, (anti)aromaticity, and quantum interference and establishes new design rules for single molecule circuits.
Collapse
Affiliation(s)
- Narendra P Arasu
- Institute of Physics Academy of Sciences of the Czech Republic, Cukrovarnická 10, 16200, Prague, Czech Republic.,Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 12000, Prague, Czech Republic
| | - Héctor Vázquez
- Institute of Physics Academy of Sciences of the Czech Republic, Cukrovarnická 10, 16200, Prague, Czech Republic
| |
Collapse
|
13
|
Li Y, Root SE, Belding L, Park J, Rawson J, Yoon HJ, Baghbanzadeh M, Rothemund P, Whitesides GM. Characterizing Chelation at Surfaces by Charge Tunneling. J Am Chem Soc 2021; 143:5967-5977. [PMID: 33834784 DOI: 10.1021/jacs.1c01800] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This paper describes a surface analysis technique that uses the "EGaIn junction" to measure tunneling current densities (J(V), amps/cm2) through self-assembled monolayers (SAMs) terminated in a chelating group and incorporating different transition metal ions. Comparisons of J(V) measurements between bare chelating groups and chelates are used to characterize the composition of the SAM and infer the dissociation constant (Kd, mol/L), as well as kinetic rate constants (koff, L/mol·s; kon, 1/s) of the reversible chelate-metal reaction. To demonstrate the concept, SAMs of 11-(4-methyl-2,2'-bipyrid-4'-yl (bpy))undecanethiol (HS(CH2)11bpy) were incubated within ethanol solutions of metal salts. After rinsing and drying the surface, measurements of current as a function of incubation time and concentration in solution are used to infer koff, kon, and Kd. X-ray photoelectron spectroscopy (XPS) provides an independent measure of surface composition to confirm inferences from J(V) measurements. Our experiments establish that (i) bound metal ions are stable to the rinsing step as long as the rinsing time, τrinse ≪ 1koff; (ii) the bound metal ions increase the current density at the negative bias and reduce the rectification observed with free bpy terminal groups; (iii) the current density as a function of the concentration of metal ions in solution follows a sigmoidal curve; and (iv) the values of Kd measured using J(V) are comparable to those measured using XPS, but larger than those measured in solution. The EGaIn junction, thus, provides a new tool for the analysis of the composition of the surfaces that undergo reversible chemical reactions with species in solution.
Collapse
Affiliation(s)
- Yuan Li
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States.,Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
| | - Samuel E Root
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Lee Belding
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Junwoo Park
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Jeff Rawson
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Hyo Jae Yoon
- Department of Chemistry, Korea University, Seoul, 02841, Korea
| | - Mostafa Baghbanzadeh
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Philipp Rothemund
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States.,John A. Paulson School of Engineering and Applied Sciences, Harvard University, 29 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - George M Whitesides
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| |
Collapse
|
14
|
O'Driscoll LJ, Bryce MR. Extended curly arrow rules to rationalise and predict structural effects on quantum interference in molecular junctions. NANOSCALE 2021; 13:1103-1123. [PMID: 33393950 DOI: 10.1039/d0nr07819k] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The ability to easily and reliably predict quantum interference (QI) behaviour would facilitate the design of functional molecular wires with potential applications in switches, transistors and thermoelectric devices. A variety of predictive methods exist, but with the exception of computationally-expensive DFT-based charge transport simulations, these often fail to account for the experimentally observed behaviour of molecules that differ significantly in structure from alternant polycyclic aromatic hydrocarbons. By considering a range of prior studies we have developed an extension to predictive "curly arrow rules". We show that, in most cases, these extended curly arrow rules (ECARs) can rationalise the type of QI exhibited by conjugated molecular wires containing heteroatoms, cross-conjugation and/or non-alternant structures. ECARs provide a straightforward "pen-and-paper" method to predict whether a molecular wire will display constructive, destructive or "shifted destructive" QI, i.e. whether or not its transmission function would be expected to show an antiresonance, and if this antiresonance would occur close to the Fermi energy or be shifted elsewhere.
Collapse
Affiliation(s)
- Luke J O'Driscoll
- Department of Chemistry, Durham University, Lower Mountjoy, Stockton Road, Durham, DH1 3LE, UK.
| | - Martin R Bryce
- Department of Chemistry, Durham University, Lower Mountjoy, Stockton Road, Durham, DH1 3LE, UK.
| |
Collapse
|
15
|
Gupta NK, Schultz T, Karuppannan SK, Vilan A, Koch N, Nijhuis CA. The energy level alignment of the ferrocene-EGaIn interface studied with photoelectron spectroscopy. Phys Chem Chem Phys 2021; 23:13458-13467. [PMID: 34095913 DOI: 10.1039/d1cp01690c] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The energy level alignment after the formation of a molecular tunnel junction is often poorly understood because spectroscopy inside junctions is not possible, which hampers the rational design of functional molecular junctions and complicates the interpretation of the data generated by molecular junctions. In molecular junction platforms where the top electrode-molecule interaction is weak; one may argue that the energy level alignment can be deduced from measurements with the molecules supported by the bottom electrode (sometimes referred to as "half junctions"). This approach, however, still relies on a series of assumptions, which are challenging to address experimentally due to difficulties in studying the molecule-top electrode interaction. Herein, we describe top electrode-molecule junctions with a liquid metal alloy top electrode of EGaIn (which stands for eutectic alloy of Ga and In) interacting with well-characterised ferrocene (Fc) moieties. We deposited a ferrocene derivative on films of EGaIn, coated with its native GaOx layer, and studied the energy level alignment with photoelectron spectroscopy. Our results reveal that the electronic interaction between the Fc and GaOx/EGaIn is very weak, resembling physisorption. Therefore, investigations of "half junctions" for this system can provide valuable information regarding the energy level alignment of complete EGaIn junctions. Our results help to improve our understanding of the energy landscape in weakly coupled molecular junctions and aid to the rational design of molecular electronic devices.
Collapse
Affiliation(s)
- Nipun Kumar Gupta
- Departement of Chemistry, Faculty of Science, National University of Singapore, Singapore, Singapore and Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, Singapore 117546, Singapore
| | - Thorsten Schultz
- Institut für Physik, Humboldt-Universität zu Berlin, Newtonstraße 15, 12489 Berlin, Germany. and Helmholtz Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein Straße 15, 12489 Berlin, Germany
| | - Senthil Kumar Karuppannan
- Departement of Chemistry, Faculty of Science, National University of Singapore, Singapore, Singapore
| | - Ayelet Vilan
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Norbert Koch
- Institut für Physik, Humboldt-Universität zu Berlin, Newtonstraße 15, 12489 Berlin, Germany. and Helmholtz Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein Straße 15, 12489 Berlin, Germany
| | - Christian A Nijhuis
- Departement of Chemistry, Faculty of Science, National University of Singapore, Singapore, Singapore and Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, Singapore 117546, Singapore and Department of Molecules and Materials, MESA+ Institute for Nanotechnology and Center for Brain-Inspired Nano Systems, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
| |
Collapse
|
16
|
Zhao Z, Wang W, Zhou X, Ni L, Kang K, Lee T, Han H, Yuan H, Guo C, Wang M, Ko MJ, Li Y, Xiang D. Crystal Size Effect on Carrier Transport of Microscale Perovskite Junctions via Soft Contact. NANO LETTERS 2020; 20:8640-8646. [PMID: 33238097 DOI: 10.1021/acs.nanolett.0c03347] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
To reduce the size of optoelectronic devices, it is essential to understand the crystal size effect on the carrier transport through microscale materials. Here, we show a soft contact method to probe the properties of irregularly shaped microscale perovskite crystals by employing a movable liquid metal electrode to form a self-adaptative deformable electrode-perovskite-electrode junction. Accordingly, we demonstrate that (1) the photocurrents of perovskite quantum dot films and microplatelets show profound differences regarding both the on/off ratio and the response time upon light illumination; and (2) small-size perovskite (<50 μm) junctions may show negative differential resistance (NDR) behavior, whereas the NDR phenomenon is absent in large-size perovskite junctions within the same bias regime. Our studies provide a method for studying arbitrary-shaped crystals without mechanical damage, assisting the understanding of the photogenerated carriers transport through microscale crystals.
Collapse
Affiliation(s)
- Zhibin Zhao
- Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Institute of Modern Optics, Nankai University, Tianjin 300350, China
- Center of Single Molecule Sciences, College of Electronic Information and Optical Engineering, Nankai University, Tianjin 300350, China
| | - Wenduo Wang
- Institute of Photoelectronic Thin Film Devices and Technology, Key Laboratory of Photoelectronic Thin Film Devices and Technology of Tianjin, Solar Energy Research Center, Nankai University, Tianjin 300350, China
| | - Xin Zhou
- Institute of Photoelectronic Thin Film Devices and Technology, Key Laboratory of Photoelectronic Thin Film Devices and Technology of Tianjin, Solar Energy Research Center, Nankai University, Tianjin 300350, China
| | - Lifa Ni
- Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Institute of Modern Optics, Nankai University, Tianjin 300350, China
- Center of Single Molecule Sciences, College of Electronic Information and Optical Engineering, Nankai University, Tianjin 300350, China
| | - Keehoon Kang
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul 08826, Korea
| | - Takhee Lee
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul 08826, Korea
| | - Hong Han
- Institute of Photoelectronic Thin Film Devices and Technology, Key Laboratory of Photoelectronic Thin Film Devices and Technology of Tianjin, Solar Energy Research Center, Nankai University, Tianjin 300350, China
| | - Hongrui Yuan
- Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Institute of Modern Optics, Nankai University, Tianjin 300350, China
| | - Chenyang Guo
- Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Institute of Modern Optics, Nankai University, Tianjin 300350, China
- Center of Single Molecule Sciences, College of Electronic Information and Optical Engineering, Nankai University, Tianjin 300350, China
| | - Maoning Wang
- Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Institute of Modern Optics, Nankai University, Tianjin 300350, China
- Center of Single Molecule Sciences, College of Electronic Information and Optical Engineering, Nankai University, Tianjin 300350, China
| | - Min Jae Ko
- Department of Chemical Engineering, Hanyang University, Seoul 04763, Korea
| | - Yuelong Li
- Institute of Photoelectronic Thin Film Devices and Technology, Key Laboratory of Photoelectronic Thin Film Devices and Technology of Tianjin, Solar Energy Research Center, Nankai University, Tianjin 300350, China
| | - Dong Xiang
- Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Institute of Modern Optics, Nankai University, Tianjin 300350, China
- Center of Single Molecule Sciences, College of Electronic Information and Optical Engineering, Nankai University, Tianjin 300350, China
| |
Collapse
|
17
|
Liu Y, Ornago L, Carlotti M, Ai Y, El Abbassi M, Soni S, Asyuda A, Zharnikov M, van der Zant HSJ, Chiechi RC. Intermolecular Effects on Tunneling through Acenes in Large-Area and Single-Molecule Junctions. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2020; 124:22776-22783. [PMID: 33093933 PMCID: PMC7569675 DOI: 10.1021/acs.jpcc.0c05781] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 09/14/2020] [Indexed: 06/11/2023]
Abstract
This paper describes the conductance of single-molecules and self-assembled monolayers comprising an oligophenyleneethynylene core, functionalized with acenes of increasing length that extend conjugation perpendicular to the path of tunneling electrons. In the Mechanically Controlled Break Junction (MCBJ) experiment, multiple conductance plateaus were identified. The high conductance plateau, which we attribute to the single molecule conformation, shows an increase of conductance as a function of acene length, in good agreement with theoretical predictions. The lower plateau is attributed to multiple molecules bridging the junctions with intermolecular interactions playing a role. In junctions comprising a self-assembled monolayer with eutectic Ga-In top-contacts (EGaIn), the pentacene derivative exhibits unusually low conductance, which we ascribe to the inability of these molecules to pack in a monolayer without introducing significant intermolecular contacts. This hypothesis is supported by the MCBJ data and theoretical calculations showing suppressed conductance through the PC films. These results highlight the role of intermolecular effects and junction geometries in the observed fluctuations of conductance values between single-molecule and ensemble junctions, and the importance of studying molecules in both platforms.
Collapse
Affiliation(s)
- Yuru Liu
- Stratingh
Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Luca Ornago
- Kavli
Institute of Nanoscience, Delft University
of Technology, Lorentzweg 1, Delft, 2628 CJ The Netherlands
| | - Marco Carlotti
- Stratingh
Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Yong Ai
- Stratingh
Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Maria El Abbassi
- Kavli
Institute of Nanoscience, Delft University
of Technology, Lorentzweg 1, Delft, 2628 CJ The Netherlands
| | - Saurabh Soni
- Stratingh
Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Andika Asyuda
- Angewandte
Physikalische Chemie, Universität
Heidelberg, Im Neuenheimer Feld 253, D-69120 Heidelberg, Germany
| | - Michael Zharnikov
- Angewandte
Physikalische Chemie, Universität
Heidelberg, Im Neuenheimer Feld 253, D-69120 Heidelberg, Germany
| | - Herre S. J. van der Zant
- Kavli
Institute of Nanoscience, Delft University
of Technology, Lorentzweg 1, Delft, 2628 CJ The Netherlands
| | - Ryan C. Chiechi
- Stratingh
Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| |
Collapse
|
18
|
Kumar S, Soni S, Danowski W, van Beek CLF, Feringa BL, Rudolf P, Chiechi RC. Correlating the Influence of Disulfides in Monolayers across Photoelectron Spectroscopy Wettability and Tunneling Charge-Transport. J Am Chem Soc 2020; 142:15075-15083. [PMID: 32786759 PMCID: PMC7472521 DOI: 10.1021/jacs.0c06508] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Indexed: 12/12/2022]
Abstract
Despite their ubiquity, self-assembled monolayers (SAMs) of thiols on coinage metals are difficult to study and are still not completely understood, particularly with respect to the nature of thiol-metal bonding. Recent advances in molecular electronics have highlighted this deficiency due to the sensitivity of tunneling charge-transport to the subtle differences in the overall composition of SAMs and the chemistry of their attachment to surfaces. These advances have also challenged assumptions about the spontaneous formation of covalent thiol-metal bonds. This paper describes a series of experiments that correlate changes in the physical properties of SAMs to photoelectron spectroscopy to unambiguously assign binding energies of noncovalent interactions to physisorbed disulfides. These disulfides can be converted to covalent metal-thiolate bonds by exposure to free thiols, leading to the remarkable observation of the total loss and recovery of length-dependent tunneling charge-transport. The identification and assignment of physisorbed disulfides solve a long-standing mystery and reveal new, dynamic properties in SAMs of thiols.
Collapse
Affiliation(s)
- Sumit Kumar
- Stratingh
Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
- Zernike
Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Saurabh Soni
- Stratingh
Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
- Zernike
Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Wojciech Danowski
- Stratingh
Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
- Zernike
Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Carlijn L. F. van Beek
- Stratingh
Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
- Zernike
Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Ben L. Feringa
- Stratingh
Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
- Zernike
Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Petra Rudolf
- Zernike
Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Ryan C. Chiechi
- Stratingh
Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
- Zernike
Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| |
Collapse
|
19
|
Soni S, Ye G, Zheng J, Zhang Y, Asyuda A, Zharnikov M, Hong W, Chiechi RC. Understanding the Role of Parallel Pathways via In-Situ Switching of Quantum Interference in Molecular Tunneling Junctions. Angew Chem Int Ed Engl 2020; 59:14308-14312. [PMID: 32469444 PMCID: PMC7497014 DOI: 10.1002/anie.202005047] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Indexed: 11/05/2022]
Abstract
This study describes the modulation of tunneling probabilities in molecular junctions by switching one of two parallel intramolecular pathways. A linearly conjugated molecular wire provides a rigid framework that allows a second, cross-conjugated pathway to be effectively switched on and off by protonation, affecting the total conductance of the junction. This approach works because a traversing electron interacts with the entire quantum-mechanical circuit simultaneously; Kirchhoff's rules do not apply. We confirm this concept by comparing the conductances of a series of compounds with single or parallel pathways in large-area junctions using EGaIn contacts and single-molecule break junctions using gold contacts. We affect switching selectively in one of two parallel pathways by converting a cross-conjugated carbonyl carbon into a trivalent carbocation, which replaces destructive quantum interference with a symmetrical resonance, causing an increase in transmission in the bias window.
Collapse
Affiliation(s)
- Saurabh Soni
- Stratingh Institute for ChemistryUniversity of GroningenNijenborgh 49747 AGGroningenThe Netherlands
- Zernike Institute for Advanced MaterialsNijenborgh 49747 AGGroningenThe Netherlands
| | - Gang Ye
- Stratingh Institute for ChemistryUniversity of GroningenNijenborgh 49747 AGGroningenThe Netherlands
- Zernike Institute for Advanced MaterialsNijenborgh 49747 AGGroningenThe Netherlands
- Center for Biomedical Optics and Photonics (CBOP) & College of Physics and Optoelectronic EngineeringKey Laboratory of Optoelectronic Devices and SystemsShenzhen UniversityShenzhen518060P. R. China
| | - Jueting Zheng
- State Key Laboratory of Physical Chemistry of Solid SurfacesCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamen361005China
| | - Yanxi Zhang
- Stratingh Institute for ChemistryUniversity of GroningenNijenborgh 49747 AGGroningenThe Netherlands
- Zernike Institute for Advanced MaterialsNijenborgh 49747 AGGroningenThe Netherlands
- Present address: MicrosystemsDepartment of Mechanical Engineering and Institute for Complex Molecular SystemsEindhoven University of Technology5600 MBEindhovenThe Netherlands
| | - Andika Asyuda
- Applied Physical ChemistryHeidelberg UniversityIm Neuenheimer Feld 253D-69120HeidelbergGermany
| | - Michael Zharnikov
- Applied Physical ChemistryHeidelberg UniversityIm Neuenheimer Feld 253D-69120HeidelbergGermany
| | - Wenjing Hong
- State Key Laboratory of Physical Chemistry of Solid SurfacesCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamen361005China
| | - Ryan C. Chiechi
- Stratingh Institute for ChemistryUniversity of GroningenNijenborgh 49747 AGGroningenThe Netherlands
- Zernike Institute for Advanced MaterialsNijenborgh 49747 AGGroningenThe Netherlands
| |
Collapse
|
20
|
Pickup BT, Fowler PW. A Correlated Source-Sink-Potential Model Consistent with the Meir–Wingreen Formula. J Phys Chem A 2020; 124:6928-6944. [DOI: 10.1021/acs.jpca.0c01711] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Barry T. Pickup
- Department of Chemistry, University of Sheffield, Sheffield S3 7HF, UK
| | - Patrick W. Fowler
- Department of Chemistry, University of Sheffield, Sheffield S3 7HF, UK
| |
Collapse
|
21
|
Soni S, Ye G, Zheng J, Zhang Y, Asyuda A, Zharnikov M, Hong W, Chiechi RC. Understanding the Role of Parallel Pathways via In‐Situ Switching of Quantum Interference in Molecular Tunneling Junctions. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202005047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Saurabh Soni
- Stratingh Institute for Chemistry University of Groningen Nijenborgh 4 9747 AG Groningen The Netherlands
- Zernike Institute for Advanced Materials Nijenborgh 4 9747 AG Groningen The Netherlands
| | - Gang Ye
- Stratingh Institute for Chemistry University of Groningen Nijenborgh 4 9747 AG Groningen The Netherlands
- Zernike Institute for Advanced Materials Nijenborgh 4 9747 AG Groningen The Netherlands
- Center for Biomedical Optics and Photonics (CBOP) & College of Physics and Optoelectronic Engineering Key Laboratory of Optoelectronic Devices and Systems Shenzhen University Shenzhen 518060 P. R. China
| | - Jueting Zheng
- State Key Laboratory of Physical Chemistry of Solid Surfaces College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 China
| | - Yanxi Zhang
- Stratingh Institute for Chemistry University of Groningen Nijenborgh 4 9747 AG Groningen The Netherlands
- Zernike Institute for Advanced Materials Nijenborgh 4 9747 AG Groningen The Netherlands
- Present address: Microsystems Department of Mechanical Engineering and Institute for Complex Molecular Systems Eindhoven University of Technology 5600 MB Eindhoven The Netherlands
| | - Andika Asyuda
- Applied Physical Chemistry Heidelberg University Im Neuenheimer Feld 253 D-69120 Heidelberg Germany
| | - Michael Zharnikov
- Applied Physical Chemistry Heidelberg University Im Neuenheimer Feld 253 D-69120 Heidelberg Germany
| | - Wenjing Hong
- State Key Laboratory of Physical Chemistry of Solid Surfaces College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 China
| | - Ryan C. Chiechi
- Stratingh Institute for Chemistry University of Groningen Nijenborgh 4 9747 AG Groningen The Netherlands
- Zernike Institute for Advanced Materials Nijenborgh 4 9747 AG Groningen The Netherlands
| |
Collapse
|
22
|
Meng M, Tang Z, Mallick S, Luo MH, Tan Z, Liu JY, Shi J, Yang Y, Liu CY, Hong W. Enhanced charge transport via d(δ)-p(π) conjugation in Mo 2-integrated single-molecule junctions. NANOSCALE 2020; 12:10320-10327. [PMID: 32367099 DOI: 10.1039/d0nr00195c] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A trans-dimolybdenum nicotinate (m-Mo2) complex and its isonicotinate isomer (p-Mo2) were synthesized and characterized crystallographically, and their single-molecule charge transport properties were investigated using the STM break junction (STM-BJ) technique. With a quadruply bonded Mo2 complex unit integrated into molecular backbones, the single-molecule conductance for complex molecules was increased by more than one order of magnitude compared with that of the organic π-conjugated analogues 1,4-bis(4-pyridyl)benzene (p-Ph) and 1,4-bis(3-pyridyl)benzene (m-Ph). More interestingly, unlike m-Ph, m-Mo2 with meta connected pyridyl anchors presents larger conductance than that of p-Mo2 with two para connected pyridyl groups. DFT-based transmission calculations revealed that the significant conductance enhancement of Mo2 molecules originates from the largely reduced HOMO-LUMO gap, and the unique d(δ)-p(π) conjugation between the Mo2 unit and the pyridine rings gives rise to a delocalized electronic structure that endows the Mo2 molecules with an unexpected high conductance.
Collapse
Affiliation(s)
- Miao Meng
- Department of Chemistry, Jinan University, 601 Huang-Pu Avenue West, Guangzhou 510632, China.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Wang X, Bennett TLR, Ismael A, Wilkinson LA, Hamill J, White AJP, Grace IM, Kolosov OV, Albrecht T, Robinson BJ, Long NJ, Cohen LF, Lambert CJ. Scale-Up of Room-Temperature Constructive Quantum Interference from Single Molecules to Self-Assembled Molecular-Electronic Films. J Am Chem Soc 2020; 142:8555-8560. [PMID: 32343894 PMCID: PMC7588028 DOI: 10.1021/jacs.9b13578] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Indexed: 01/25/2023]
Abstract
The realization of self-assembled molecular-electronic films, whose room-temperature transport properties are controlled by quantum interference (QI), is an essential step in the scale-up of QI effects from single molecules to parallel arrays of molecules. Recently, the effect of destructive QI (DQI) on the electrical conductance of self-assembled monolayers (SAMs) has been investigated. Here, through a combined experimental and theoretical investigation, we demonstrate chemical control of different forms of constructive QI (CQI) in cross-plane transport through SAMs and assess its influence on cross-plane thermoelectricity in SAMs. It is known that the electrical conductance of single molecules can be controlled in a deterministic manner, by chemically varying their connectivity to external electrodes. Here, by employing synthetic methodologies to vary the connectivity of terminal anchor groups around aromatic anthracene cores, and by forming SAMs of the resulting molecules, we clearly demonstrate that this signature of CQI can be translated into SAM-on-gold molecular films. We show that the conductance of vertical molecular junctions formed from anthracene-based molecules with two different connectivities differ by a factor of approximately 16, in agreement with theoretical predictions for their conductance ratio based on CQI effects within the core. We also demonstrate that for molecules with thioether anchor groups, the Seebeck coefficient of such films is connectivity dependent and with an appropriate choice of connectivity can be boosted by ∼50%. This demonstration of QI and its influence on thermoelectricity in SAMs represents a critical step toward functional ultra-thin-film devices for future thermoelectric and molecular-scale electronics applications.
Collapse
Affiliation(s)
- Xintai Wang
- Physics
Department, Lancaster University, Lancaster LA1 4YB, U.K.
- The
Blackett Laboratory, Imperial College London, South Kensington Campus, London SW7 2AZ, U.K.
| | - Troy L. R. Bennett
- Department
of Chemistry, Imperial College London, MSRH, White City, London W12 0BZ, U.K.
| | - Ali Ismael
- Physics
Department, Lancaster University, Lancaster LA1 4YB, U.K.
- Department
of Physics, College of Education for Pure Science, Tikrit University, Tikrit, Iraq
| | - Luke A. Wilkinson
- Department
of Chemistry, Imperial College London, MSRH, White City, London W12 0BZ, U.K.
| | - Joseph Hamill
- Department
of Chemistry, Birmingham University, Edgbaston, Birmingham B15 2TT, U.K.
| | - Andrew J. P. White
- Department
of Chemistry, Imperial College London, MSRH, White City, London W12 0BZ, U.K.
| | - Iain M. Grace
- Physics
Department, Lancaster University, Lancaster LA1 4YB, U.K.
| | - Oleg V. Kolosov
- Physics
Department, Lancaster University, Lancaster LA1 4YB, U.K.
| | - Tim Albrecht
- Department
of Chemistry, Birmingham University, Edgbaston, Birmingham B15 2TT, U.K.
| | | | - Nicholas J. Long
- Department
of Chemistry, Imperial College London, MSRH, White City, London W12 0BZ, U.K.
| | - Lesley F. Cohen
- The
Blackett Laboratory, Imperial College London, South Kensington Campus, London SW7 2AZ, U.K.
| | - Colin J. Lambert
- Physics
Department, Lancaster University, Lancaster LA1 4YB, U.K.
| |
Collapse
|
24
|
Liu Y, Zhong M, Downey EF, Chen X, Li T, Nørgaard K, Wei Z. Temperature dependence of charge transport in solid-state molecular junctions based on oligo(phenylene ethynylene)s. NANOTECHNOLOGY 2020; 31:164001. [PMID: 31891933 DOI: 10.1088/1361-6528/ab6681] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The ultimate goal of molecular electronics is to achieve practical applications. For approaching the target, we have successfully fabricated solid-state junctions based on oligo(phenylene ethynylene)s (OPEs) and cruciform OPEs with extended tetrathiafulvalene (TTF) (OPE3 and OPE3-TTF) self-assembled monolayers (SAMs) with a diamine anchoring group. SAMs were confined in micropores with gold substrates to ensure well-defined device surface areas. The transport properties were conducted on a double-junction layout, which the rGO films used for top contacts and interconnects between adjacent SAMs. The solid-state devices based on OPE3-TTF SAMs showed the expected higher conductance under ambient conditions because of the incorporation of a TTF moiety. The two devices displayed varying degrees of temperature dependence with decreasing temperature, which resulted from the cross-conjugated OPE3-TTF molecule exhibiting quantum interference while the linear-conjugated OPE3 molecule did not. This study shows the temperature dependence of the electrical properties of molecular devices based on cruciform OPEs, further enriching the research results of functional molecular devices.
Collapse
Affiliation(s)
- Yuqing Liu
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences & Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100083, People's Republic of China. Sino-Danish College, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China. Nano-Science Center and Department of Chemistry, University of Copenhagen, Copenhagen DK-2100, Denmark
| | | | | | | | | | | | | |
Collapse
|
25
|
Baghernejad M, Van Dyck C, Bergfield J, Levine DR, Gubicza A, Tovar JD, Calame M, Broekmann P, Hong W. Quantum Interference Enhanced Chemical Responsivity in Single‐Molecule Dithienoborepin Junctions. Chemistry 2019; 25:15141-15146. [DOI: 10.1002/chem.201903315] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Indexed: 11/08/2022]
Affiliation(s)
- Masoud Baghernejad
- Transport at Nanoscale Interface Laboratory Empa, Swiss Federal Laboratories for Materials Science and Technology 8600 Dübendorf Switzerland
- Department of Chemistry and Biochemistry University of Bern Freiestrasse 3 3012 Bern Switzerland
- Department of Physics University of Basel Klingelbergstrasse 56 4056 Basel Switzerland
| | - Colin Van Dyck
- Department of Physics University of Mons 20, place du parc 7000 Mons Belgium
| | - Justin Bergfield
- Department of Physics and Department of Chemistry Illinois State University Moulton Hall USA
| | - David R. Levine
- Department of Chemistry and Department of Materials Science and Engineering Johns Hopkins University 3400 N. Charles Street Baltimore MD 21218 USA
| | - Agnes Gubicza
- Transport at Nanoscale Interface Laboratory Empa, Swiss Federal Laboratories for Materials Science and Technology 8600 Dübendorf Switzerland
| | - John D. Tovar
- Department of Chemistry and Department of Materials Science and Engineering Johns Hopkins University 3400 N. Charles Street Baltimore MD 21218 USA
| | - Michel Calame
- Transport at Nanoscale Interface Laboratory Empa, Swiss Federal Laboratories for Materials Science and Technology 8600 Dübendorf Switzerland
- Department of Physics University of Basel Klingelbergstrasse 56 4056 Basel Switzerland
| | - Peter Broekmann
- Department of Chemistry and Biochemistry University of Bern Freiestrasse 3 3012 Bern Switzerland
| | - Wenjing Hong
- Department of Chemistry and Biochemistry University of Bern Freiestrasse 3 3012 Bern Switzerland
- State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, NEL, College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 China
| |
Collapse
|
26
|
Naghibi S, Ismael AK, Vezzoli A, Al-Khaykanee MK, Zheng X, Grace IM, Bethell D, Higgins SJ, Lambert CJ, Nichols RJ. Synthetic Control of Quantum Interference by Regulating Charge on a Single Atom in Heteroaromatic Molecular Junctions. J Phys Chem Lett 2019; 10:6419-6424. [PMID: 31577147 PMCID: PMC7007252 DOI: 10.1021/acs.jpclett.9b02319] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
A key area of activity in contemporary molecular electronics is the chemical control of conductance of molecular junctions and devices. Here we study and modify a range of pyrrolodipyridines (carbazole-like) molecular wires. We are able to change the electrical conductance and quantum interference patterns by chemically regulating the bridging nitrogen atom in the tricyclic ring system. A series of eight different N-substituted pyrrolodipyridines has been synthesized and subjected to single-molecule electrical characterization using an STM break junction. Correlations of these experimental data with theoretical calculations underline the importance of the pyrrolic nitrogen in facilitating conductance across the molecular bridge and controlling quantum interference. The large chemical modulation for the meta-connected series is not apparent for the para-series, showing the competition between (i) meta-connectivity quantum interference phenomena and (ii) the ability of the pyrrolic nitrogen to facilitate conductance, that can be modulated by chemical substitution.
Collapse
Affiliation(s)
- Saman Naghibi
- Department
of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, U.K.
| | - Ali K. Ismael
- Department
of Physics, Lancaster University, Lancaster LA1 4YB, U.K.
- Department
of Physics, College of Education for Pure Science, Tikrit University, Tikrit 34001, Iraq
| | - Andrea Vezzoli
- Department
of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, U.K.
- E-mail:
| | - Mohsin K. Al-Khaykanee
- Department
of Physics, Lancaster University, Lancaster LA1 4YB, U.K.
- Department
of Physics, College of Science, University
of Babylon, Babylon 51002, Iraq
| | - Xijia Zheng
- Department
of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, U.K.
| | - Iain M. Grace
- Department
of Physics, Lancaster University, Lancaster LA1 4YB, U.K.
| | - Donald Bethell
- Department
of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, U.K.
| | - Simon J. Higgins
- Department
of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, U.K.
| | - Colin J. Lambert
- Department
of Physics, Lancaster University, Lancaster LA1 4YB, U.K.
- E-mail:
| | - Richard J. Nichols
- Department
of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, U.K.
- E-mail:
| |
Collapse
|
27
|
Li Y, Yu X, Zhen Y, Dong H, Hu W. Transmission mechanism and quantum interference in fused thienoacenes coupling to Au electrodes through the thiophene rings. Phys Chem Chem Phys 2019; 21:16293-16301. [PMID: 31304481 DOI: 10.1039/c9cp02249j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
So far, quantum interference in molecular devices where the anchors are inseparable parts of the whole molecule has been seldom discussed. In this article, we perform first-principles calculations on the electronic transmission properties of a series of Au-thienoacene-Au junctions where the molecule interacts with electrodes through the S atoms in thiophene rings in a fused-ring system. The calculated binding energy of the Au-S interaction is highly dependent on the substitution sites of the thiophene rings, which agrees with the experimental report that the Au-S interaction is too weak to form a junction for some molecules. The electronic coupling at the molecule-electrode contact is also affected by the molecular structure. To distinguish the coupling mechanism, we show the importance of investigating the electron distribution of frontier molecular orbitals in combination with the percentage of the π system in the partial density of states on the S atoms. Because of the difference in electronic coupling, comparison between molecules should be done with care. On the other hand, conductance suppression due to the destructive quantum interference originating from the molecular topology is demonstrated by comparing the properties of isomers with similar molecule-electrode coupling.
Collapse
Affiliation(s)
- Yang Li
- Beijing National Laboratory for Molecular Science, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
| | - Xi Yu
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science, Tianjin University and Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, China.
| | - Yonggang Zhen
- Beijing National Laboratory for Molecular Science, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
| | - Huanli Dong
- Beijing National Laboratory for Molecular Science, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
| | - Wenping Hu
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science, Tianjin University and Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, China.
| |
Collapse
|
28
|
Gil-Guerrero S, Ramos-Berdullas N, Martín Pendás Á, Francisco E, Mandado M. Anti-ohmic single molecule electron transport: is it feasible? NANOSCALE ADVANCES 2019; 1:1901-1913. [PMID: 36134239 PMCID: PMC9417330 DOI: 10.1039/c8na00384j] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 03/07/2019] [Indexed: 06/10/2023]
Abstract
Hitherto, only molecular wires with a regular ohmic behavior in which the electric conductance decreases with the wire length have been synthesized. Implementation of molecular conductors with reversed conductance/length trend (anti-ohmic) might revolutionize the field of molecular electronics, allowing the development of electronic devices with extraordinary properties. It is for this reason that, recently, theoretical efforts have been focused on this topic and different structures have been proposed to show reversed conductance/length behavior on the basis of density functional theory non-equilibrium Green function approach (DFT-NEGF) and topological models. From the previous works, it can be stated that an anti-ohmic molecular wire must display a very small HOMO-LUMO gap and a reversed bond alternation pattern in the case of polyenes and related conjugated systems. In this work, the pursuit of a mechanism by which the anti-ohmic electron transport may arise was carried out by studying the paradigmatic anti-ohmic p-xylylene chain (pX2) at the DFT level in combination with topological models. It has been found that the electron transport in the anti-ohmic regime is favored by a long-range superexchange mechanism, which, contrary to what is expected, is reinforced by the increase in the length of the chain. Moreover, strong links between anti-ohmic character in molecular wires and one-dimensional topological insulator models have been established. Due to the small HOMO-LUMO gap predicted at DFT level, the anti-ohmic character has been put to the proof using a multireference scenario. Preliminary results point out to the presence of different ohmic and anti-ohmic electronic states. In the particular case of pX2 the anti-ohmic states do not correspond to the ground state. These findings require a reconsideration of previous studies on the reversed conductance/length behavior using single reference methodologies.
Collapse
Affiliation(s)
- Sara Gil-Guerrero
- Department of Physical Chemistry, University of Vigo Lagoas-Marcosende s/n 36310 Vigo Spain
| | - Nicolás Ramos-Berdullas
- Department of Physical Chemistry, University of Vigo Lagoas-Marcosende s/n 36310 Vigo Spain
- Institute of Theoretical Chemistry, University of Vienna Währinger Str. 17 1090 Vienna Austria
| | - Ángel Martín Pendás
- Department of Analytical and Physical Chemistry, University of Oviedo Calle Julían Clavería 8 33006 Oviedo Spain
| | - Evelio Francisco
- Department of Analytical and Physical Chemistry, University of Oviedo Calle Julían Clavería 8 33006 Oviedo Spain
| | - Marcos Mandado
- Department of Physical Chemistry, University of Vigo Lagoas-Marcosende s/n 36310 Vigo Spain
| |
Collapse
|
29
|
Carlotti M, Soni S, Qiu X, Sauter E, Zharnikov M, Chiechi RC. Systematic experimental study of quantum interference effects in anthraquinoid molecular wires. NANOSCALE ADVANCES 2019; 1:2018-2028. [PMID: 31304460 PMCID: PMC6592160 DOI: 10.1039/c8na00223a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 02/07/2019] [Indexed: 05/17/2023]
Abstract
In order to translate molecular properties in molecular-electronic devices, it is necessary to create design principles that can be used to achieve better structure-function control oriented toward device fabrication. In molecular tunneling junctions, cross-conjugation tends to give rise to destructive quantum interference effects that can be tuned by changing the electronic properties of the molecules. We performed a systematic study of the tunneling charge-transport properties of a series of compounds characterized by an identical cross-conjugated anthraquinoid molecular skeleton but bearing different substituents at the 9 and 10 positions that affect the energies and localization of their frontier orbitals. We compared the experimental results across three different experimental platforms in both single-molecule and large-area junctions and found a general agreement. Combined with theoretical models, these results separate the intrinsic properties of the molecules from platform-specific effects. This work is a step towards explicit synthetic control over tunneling charge transport targeted at specific functionality in (proto-)devices.
Collapse
Affiliation(s)
- Marco Carlotti
- Zernike Institute for Advanced Materials , Nijenborgh 4 , 9747 AG Groningen , The Netherlands .
- Stratingh Institute for Chemistry , University of Groningen , Nijenborgh 4 , 9747 AG Groningen , The Netherlands
| | - Saurabh Soni
- Zernike Institute for Advanced Materials , Nijenborgh 4 , 9747 AG Groningen , The Netherlands .
- Stratingh Institute for Chemistry , University of Groningen , Nijenborgh 4 , 9747 AG Groningen , The Netherlands
| | - Xinkai Qiu
- Zernike Institute for Advanced Materials , Nijenborgh 4 , 9747 AG Groningen , The Netherlands .
- Stratingh Institute for Chemistry , University of Groningen , Nijenborgh 4 , 9747 AG Groningen , The Netherlands
| | - Eric Sauter
- Applied Physical Chemistry , Heidelberg University , Im Neuenheier Feld 253 , Heidelberg 69120 , Germany
| | - Michael Zharnikov
- Applied Physical Chemistry , Heidelberg University , Im Neuenheier Feld 253 , Heidelberg 69120 , Germany
| | - Ryan C Chiechi
- Zernike Institute for Advanced Materials , Nijenborgh 4 , 9747 AG Groningen , The Netherlands .
- Stratingh Institute for Chemistry , University of Groningen , Nijenborgh 4 , 9747 AG Groningen , The Netherlands
| |
Collapse
|
30
|
Gu J, Wu W, Stuyver T, Danovich D, Hoffmann R, Tsuji Y, Shaik S. Cross Conjugation in Polyenes and Related Hydrocarbons: What Can Be Learned from Valence Bond Theory about Single-Molecule Conductance? J Am Chem Soc 2019; 141:6030-6047. [DOI: 10.1021/jacs.9b01420] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Junjing Gu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China
| | - Wei Wu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China
| | - 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
| | - Roald Hoffmann
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
| | - Yuta Tsuji
- Institute for Materials Chemistry and Engineering and IRCCS, Kyushu University, Nishi-ku, Fukuoka 819-0395, Japan
| | - Sason Shaik
- Department of Organic Chemistry and the Lise Meitner-Minerva Centre for Computational Quantum Chemistry, The Hebrew University, Jerusalem 91904, Israel
| |
Collapse
|
31
|
Gao H, Mallick S, Cao L, Meng M, Cheng T, Chen HW, Liu CY. Electronic Coupling and Electron Transfer between Two Mo 2 Units through meta- and para-Phenylene Bridges. Chemistry 2019; 25:3930-3938. [PMID: 30561861 DOI: 10.1002/chem.201805866] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2018] [Indexed: 11/09/2022]
Abstract
A series of three Mo2 dimers bridged by a meta-phenylene group has been studied in terms of electronic coupling (EC) and electron transfer (ET) in comparison with the para isomers. Optical analyses on the mixed-valence complexes indicate that by replacing a para-phenylene bridge with a meta one, the EC between the two Mo2 centers is dramatically weakened; consequently, the ET rates (ket ) are lowered by two to three orders of magnitude. In the para series, the EC parameters (Hab ) and ET rates (ket ) are greatly affected by O/S atomic alternation of the bridging ligand. However, for the meta analogues, similar EC and ET parameters are obtained, that is, Hab =300-400 cm-1 and ket ≈109 s-1 . These results suggest that through-σ-bond and/or through-space coupling channels become operative as the π conjugation is disabled. DFT calculations reveal that destructive quantum interference features seen for the meta series arise from the cancellation of two π-conjugated coupling pathways.
Collapse
Affiliation(s)
- Hang Gao
- Department of Chemistry, Jinan University, 601 Huang-Pu Avenue West, Guangzhou, 510632, P. R. China
| | - Suman Mallick
- Department of Chemistry, Jinan University, 601 Huang-Pu Avenue West, Guangzhou, 510632, P. R. China
| | - Lijiu Cao
- Department of Chemistry, Jinan University, 601 Huang-Pu Avenue West, Guangzhou, 510632, P. R. China
| | - Miao Meng
- Department of Chemistry, Jinan University, 601 Huang-Pu Avenue West, Guangzhou, 510632, P. R. China
| | - Tao Cheng
- Department of Chemistry, Jinan University, 601 Huang-Pu Avenue West, Guangzhou, 510632, P. R. China
| | - Huo Wen Chen
- Department of Chemistry, Jinan University, 601 Huang-Pu Avenue West, Guangzhou, 510632, P. R. China
| | - Chun Y Liu
- Department of Chemistry, Jinan University, 601 Huang-Pu Avenue West, Guangzhou, 510632, P. R. China
| |
Collapse
|
32
|
Liu J, Huang X, Wang F, Hong W. Quantum Interference Effects in Charge Transport through Single-Molecule Junctions: Detection, Manipulation, and Application. Acc Chem Res 2019; 52:151-160. [PMID: 30500161 DOI: 10.1021/acs.accounts.8b00429] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Quantum interference effects (QIEs), which offer unique opportunities for the fine-tuning of charge transport through molecular building blocks by constructive or destructive quantum interference, have become an emerging area in single-molecule electronics. Benefiting from the QIEs, charge transport through molecular systems can be controlled through minor structural and environmental variations, which cause various charge transport states to be significantly changed from conductive to insulative states and offer promising applications in future functional single-molecule devices. Although QIEs were predicted by theoreticians more than two decades ago, only since 2011 have the challenges in ultralow conductance detection originating from destructive quantum interference been overcome experimentally. Currently, a series of single-molecule conductance investigations have been carried out experimentally to detect constructive and destructive QIEs in charge transport through various types of molecular junctions by altering molecular patterns and connectivities. Furthermore, the use of QIEs to tune the properties of charge transport through single-molecule junctions using external gating shows vital potential in future molecular electronic devices. The experimental and theoretical investigations of QIEs offer new fundamental understanding of the structural-electronic relationships in molecular devices and materials at the nanoscale. In this Account, we discuss our progress toward the experimental detection, manipulation, and further application of QIEs in charge transport through single-molecule junctions. These experiments were carried out continuously in our previous group at the University of Bern and in our lab at Xiamen University. As a result of the development of mechanically controllable break junction (MCBJ) and scanning tunneling microscope break junction (STM-BJ) techniques, we could detect ultralow charge transport through the cross-conjugated anthraquinone center, which was one of the earliest experimental studies of QIEs. In close cooperation with organic chemists and theoretical physicists, we systematically investigated charge transport through single-molecule junctions originating from QIEs in conjugated centers ranging from simple single benzene to polycyclic aromatic hydrocarbons (PAHs), heteroaromatics, and even complicated metalla-aromatics at room temperature. Then we further investigated the quantitative correlation between molecular structure and quantum interference by altering different molecular patterns and connectivities in homologous series of PAHs and heteroatom systems. Additionally, external chemical and electrochemical gating of single-molecule devices can be used for direct QIE manipulation via not only tuning molecular conjugation but also shifting the electrode Fermi level. Our study further suggested that distinguishable differences in conductance resulting from QIEs offer opportunities to detect photothermal reaction kinetics and to recognize isomers at the single-molecule scale. These investigations demonstrate the universality of QIEs in charge transport through various molecular building blocks. Moreover, effective manipulation of QIEs leads to various novel phenomena and promising applications in molecular electronic devices.
Collapse
Affiliation(s)
- Junyang Liu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, NEL, Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Xiaoyan Huang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, NEL, Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Fei Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, NEL, Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Wenjing Hong
- State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, NEL, Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| |
Collapse
|
33
|
Carlotti M, Soni S, Kumar S, Ai Y, Sauter E, Zharnikov M, Chiechi RC. Two-Terminal Molecular Memory through Reversible Switching of Quantum Interference Features in Tunneling Junctions. Angew Chem Int Ed Engl 2018; 57:15681-15685. [PMID: 30260083 PMCID: PMC6283355 DOI: 10.1002/anie.201807879] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Indexed: 11/11/2022]
Abstract
Large-area molecular tunneling junctions comprising self-assembled monolayers of redox-active molecules are described that exhibit two-terminal bias switching. The as-prepared monolayers undergo partial charge transfer to the underlying metal substrate (Au, Pt, or Ag), which converts their cores from a quinoid to a hydroquinoid form. The resulting rearomatization converts the bond topology from a cross-conjugated to a linearly conjugated π system. The cross-conjugated form correlates to the appearance of an interference feature in the transmission spectrum that vanishes for the linearly conjugated form. Owing to the presence of electron-withdrawing nitrile groups, the reduction potential and the interference feature lie close to the work function and Fermi level of the metallic substrate. We exploited the relationship between conjugation patterns and quantum interference to create nonvolatile memory in proto-devices using eutectic Ga-In as the top contact.
Collapse
Affiliation(s)
- Marco Carlotti
- Stratingh Institute for ChemistryUniversity of GroningenNijenborgh 49747 AGGroningenThe Netherlands
- Zernike Institute for Advanced MaterialsNijenborgh 49747 AGGroningenThe Netherlands
| | - Saurabh Soni
- Stratingh Institute for ChemistryUniversity of GroningenNijenborgh 49747 AGGroningenThe Netherlands
- Zernike Institute for Advanced MaterialsNijenborgh 49747 AGGroningenThe Netherlands
| | - Sumit Kumar
- Stratingh Institute for ChemistryUniversity of GroningenNijenborgh 49747 AGGroningenThe Netherlands
- Zernike Institute for Advanced MaterialsNijenborgh 49747 AGGroningenThe Netherlands
| | - Yong Ai
- Stratingh Institute for ChemistryUniversity of GroningenNijenborgh 49747 AGGroningenThe Netherlands
- Zernike Institute for Advanced MaterialsNijenborgh 49747 AGGroningenThe Netherlands
| | - Eric Sauter
- Applied Physical ChemistryHeidelberg UniversityIm Neuenheimer Feld 253Heidelberg69120Germany
| | - Michael Zharnikov
- Applied Physical ChemistryHeidelberg UniversityIm Neuenheimer Feld 253Heidelberg69120Germany
| | - Ryan C. Chiechi
- Stratingh Institute for ChemistryUniversity of GroningenNijenborgh 49747 AGGroningenThe Netherlands
- Zernike Institute for Advanced MaterialsNijenborgh 49747 AGGroningenThe Netherlands
| |
Collapse
|
34
|
Alqahtani J, Sadeghi H, Sangtarash S, Lambert CJ. Breakdown of Curly Arrow Rules in Anthraquinone. Angew Chem Int Ed Engl 2018; 57:15065-15069. [PMID: 30208251 DOI: 10.1002/anie.201807257] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Indexed: 11/08/2022]
Abstract
Understanding and controlling quantum interference (QI) in single molecules is fundamental to the development of QI-based single-molecule electronics. Simple rules such as counting rules, curly arrow rules (CARs), circuit rules, and more recently magic ratio rules have been developed to predict QI patterns in polycyclic aromatic hydrocarbons. CARs are widely used to predict destructive QI. Here we examine the validity of CARs in fully conjugated anthracene and dihydroxyanthracene, cross-conjugated anthraquinone, and broken conjugated dihydroanthracene attached to either graphene or gold electrodes through π-π stacking or thiol and Au-C anchors. For the first time, we demonstrate that CARs break down in molecular junctions formed by cross-conjugated anthraquinone. In contrast with the destructive QI predicted by CARs for a meta-connected anthraquinone core, we demonstrate that QI is constructive. This behavior is independent of the choice of electrode material or anchor groups. This is significant, because by changing the redox state of meta-connected dihydroxyanthracene to form meta-connected anthraquinone, the conductance of the junction increases by a couple of orders of magnitude due to the crossover from constructive to destructive QI. This opens new avenues for realization of QI-based single-molecule switches.
Collapse
Affiliation(s)
- Jehan Alqahtani
- Physics Department, Lancaster University, Lancaster, LA1 4YB, UK
| | - Hatef Sadeghi
- Physics Department, Lancaster University, Lancaster, LA1 4YB, UK
| | - Sara Sangtarash
- Physics Department, Lancaster University, Lancaster, LA1 4YB, UK
| | - Colin J Lambert
- Physics Department, Lancaster University, Lancaster, LA1 4YB, UK
| |
Collapse
|
35
|
Carlotti M, Soni S, Kumar S, Ai Y, Sauter E, Zharnikov M, Chiechi RC. Two-Terminal Molecular Memory through Reversible Switching of Quantum Interference Features in Tunneling Junctions. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201807879] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Marco Carlotti
- Stratingh Institute for Chemistry; University of Groningen; Nijenborgh 4 9747 AG Groningen The Netherlands
- Zernike Institute for Advanced Materials; Nijenborgh 4 9747 AG Groningen The Netherlands
| | - Saurabh Soni
- Stratingh Institute for Chemistry; University of Groningen; Nijenborgh 4 9747 AG Groningen The Netherlands
- Zernike Institute for Advanced Materials; Nijenborgh 4 9747 AG Groningen The Netherlands
| | - Sumit Kumar
- Stratingh Institute for Chemistry; University of Groningen; Nijenborgh 4 9747 AG Groningen The Netherlands
- Zernike Institute for Advanced Materials; Nijenborgh 4 9747 AG Groningen The Netherlands
| | - Yong Ai
- Stratingh Institute for Chemistry; University of Groningen; Nijenborgh 4 9747 AG Groningen The Netherlands
- Zernike Institute for Advanced Materials; Nijenborgh 4 9747 AG Groningen The Netherlands
| | - Eric Sauter
- Applied Physical Chemistry; Heidelberg University; Im Neuenheimer Feld 253 Heidelberg 69120 Germany
| | - Michael Zharnikov
- Applied Physical Chemistry; Heidelberg University; Im Neuenheimer Feld 253 Heidelberg 69120 Germany
| | - Ryan C. Chiechi
- Stratingh Institute for Chemistry; University of Groningen; Nijenborgh 4 9747 AG Groningen The Netherlands
- Zernike Institute for Advanced Materials; Nijenborgh 4 9747 AG Groningen The Netherlands
| |
Collapse
|
36
|
Gorbatsevich AA, Krasnikov GY, Shubin NM. [Formula: see text]-symmetric interference transistor. Sci Rep 2018; 8:15780. [PMID: 30361561 PMCID: PMC6202334 DOI: 10.1038/s41598-018-34132-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 10/07/2018] [Indexed: 11/12/2022] Open
Abstract
We present a model of the molecular transistor, operation of which is based on the interplay between two physical mechanisms, peculiar to open quantum systems that act in concert: [Formula: see text] -symmetry breaking corresponding to coalescence of resonances at the exceptional point of the molecule, connected to the leads, and Fano-Feshbach antiresonance. This switching mechanism can be realised in particular in a special class of molecules with degenerate energy levels, e.g. diradicals, which possess mirror symmetry. At zero gate voltage infinitesimally small interaction of the molecule with the leads breaks the [Formula: see text] -symmetry of the system that, however, can be restored by application of the gate voltage preserving the mirror symmetry. [Formula: see text] -symmetry broken state at zero gate voltage with minimal transmission corresponds to the "off" state while the [Formula: see text] -symmetric state at non-zero gate voltage with maximum transmission - to the "on" state. At zero gate voltage energy of the antiresonance coincides with exceptional point. We construct a model of an all-electrical molecular switch based on such transistors acting as a conventional CMOS inverter and show that essentially lower power consumption and switching energy can be achieved, compared to the CMOS analogues.
Collapse
Affiliation(s)
- Alexander A. Gorbatsevich
- P.N. Lebedev Physical Institute of the Russian Academy of Sciences, Division of solid state physics, Moscow, 119991 Russia
- JSC Molecular Electronics Research Institute, Zelenograd, Moscow 124460 Russia
| | | | - Nikolay M. Shubin
- P.N. Lebedev Physical Institute of the Russian Academy of Sciences, Division of solid state physics, Moscow, 119991 Russia
- JSC Molecular Electronics Research Institute, Zelenograd, Moscow 124460 Russia
- Department of quantum physics and nanoelectronics, National Research University of Electronic Technology, Zelenograd, Moscow 124498 Russia
| |
Collapse
|
37
|
Alqahtani J, Sadeghi H, Sangtarash S, Lambert CJ. Breakdown of Curly Arrow Rules in Anthraquinone. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201807257] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
| | - Hatef Sadeghi
- Physics DepartmentLancaster University Lancaster LA1 4YB UK
| | | | | |
Collapse
|
38
|
Abstract
This paper reviews the present status of unimolecular electronics (UME). The field started in the 1970s with a hope that some day organic molecules (∼2 nm in size), when used as electronic components, would challenge Si-based inorganic electronics in ultimate-high-density integrated circuits. The technological push to ever smaller inorganic device sizes (Moore's "law") was driven by a profit motive and by vast investments. UME, the underfunded pauper, may have lost that "race to the bottom", but some excellent science is left to be done.
Collapse
Affiliation(s)
- Robert Melville Metzger
- Laboratory for Molecular Electronics, Department of Chemistry and Biochemistry, University of Alabama, Box 870336, Tuscaloosa, AL 35487-0336, USA.
| |
Collapse
|
39
|
Zhang Y, Ye G, Soni S, Qiu X, Krijger TL, Jonkman HT, Carlotti M, Sauter E, Zharnikov M, Chiechi RC. Controlling destructive quantum interference in tunneling junctions comprising self-assembled monolayers via bond topology and functional groups. Chem Sci 2018; 9:4414-4423. [PMID: 29896382 PMCID: PMC5961448 DOI: 10.1039/c8sc00165k] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 04/22/2018] [Indexed: 01/25/2023] Open
Abstract
Quantum interference effects (QI) are of interest in nano-scale devices based on molecular tunneling junctions because they can affect conductance exponentially through minor structural changes. However, their utilization requires the prediction and deterministic control over the position and magnitude of QI features, which remains a significant challenge. In this context, we designed and synthesized three benzodithiophenes based molecular wires; one linearly-conjugated, one cross-conjugated and one cross-conjugated quinone. Using eutectic Ga-In (EGaIn) and CP-AFM, we compared them to a well-known anthraquinone in molecular junctions comprising self-assembled monolayers (SAMs). By combining density functional theory and transition voltage spectroscopy, we show that the presence of an interference feature and its position can be controlled independently by manipulating bond topology and electronegativity. This is the first study to separate these two parameters experimentally, demonstrating that the conductance of a tunneling junction depends on the position and depth of a QI feature, both of which can be controlled synthetically.
Collapse
Affiliation(s)
- Yanxi Zhang
- Stratingh Institute for Chemistry , University of Groningen , Nijenborgh 4 , 9747 AG Groningen , The Netherlands . .,Zernike Institute for Advanced Materials , Nijenborgh 4 , 9747 AG Groningen , The Netherlands
| | - Gang Ye
- Stratingh Institute for Chemistry , University of Groningen , Nijenborgh 4 , 9747 AG Groningen , The Netherlands . .,Zernike Institute for Advanced Materials , Nijenborgh 4 , 9747 AG Groningen , The Netherlands
| | - Saurabh Soni
- Stratingh Institute for Chemistry , University of Groningen , Nijenborgh 4 , 9747 AG Groningen , The Netherlands . .,Zernike Institute for Advanced Materials , Nijenborgh 4 , 9747 AG Groningen , The Netherlands
| | - Xinkai Qiu
- Stratingh Institute for Chemistry , University of Groningen , Nijenborgh 4 , 9747 AG Groningen , The Netherlands . .,Zernike Institute for Advanced Materials , Nijenborgh 4 , 9747 AG Groningen , The Netherlands
| | - Theodorus L Krijger
- Stratingh Institute for Chemistry , University of Groningen , Nijenborgh 4 , 9747 AG Groningen , The Netherlands . .,Zernike Institute for Advanced Materials , Nijenborgh 4 , 9747 AG Groningen , The Netherlands
| | - Harry T Jonkman
- Zernike Institute for Advanced Materials , Nijenborgh 4 , 9747 AG Groningen , The Netherlands
| | - Marco Carlotti
- Stratingh Institute for Chemistry , University of Groningen , Nijenborgh 4 , 9747 AG Groningen , The Netherlands . .,Zernike Institute for Advanced Materials , Nijenborgh 4 , 9747 AG Groningen , The Netherlands
| | - Eric Sauter
- Applied Physical Chemistry , Heidelberg University , Im Neuenheier Feld 253 , Heidelberg 69120 , Germany
| | - Michael Zharnikov
- Applied Physical Chemistry , Heidelberg University , Im Neuenheier Feld 253 , Heidelberg 69120 , Germany
| | - Ryan C Chiechi
- Stratingh Institute for Chemistry , University of Groningen , Nijenborgh 4 , 9747 AG Groningen , The Netherlands . .,Zernike Institute for Advanced Materials , Nijenborgh 4 , 9747 AG Groningen , The Netherlands
| |
Collapse
|
40
|
Lo KC, Hau KI, Chan WK. Photoconductivity enhancement and charge transport properties in ruthenium-containing block copolymer/carbon nanotube hybrids. NANOSCALE 2018; 10:6474-6486. [PMID: 29569662 DOI: 10.1039/c7nr09670d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Functional polymer/carbon nanotube (CNT) hybrid materials can serve as a good model for light harvesting systems based on CNTs. This paper presents the synthesis of block copolymer/CNT hybrids and the characterization of their photocurrent responses by both experimental and computational approaches. A series of functional diblock copolymers was synthesized by reversible addition-fragmentation chain transfer polymerizations for the dispersion and functionalization of CNTs. The block copolymers contain photosensitizing ruthenium complexes and modified pyrene-based anchoring units. The photocurrent responses of the polymer/CNT hybrids were measured by photoconductive atomic force microscopy (PCAFM), from which the experimental data were analyzed by vigorous statistical models. The difference in photocurrent response among different hybrids was correlated to the conformations of the hybrids, which were elucidated by molecular dynamics simulations, and the electronic properties of polymers. The photoresponse of the block copolymer/CNT hybrids can be enhanced by introducing an electron-accepting block between the photosensitizing block and the CNT. We have demonstrated that the application of a rigorous statistical methodology can unravel the charge transport properties of these hybrid materials and provide general guidelines for the design of molecular light harvesting systems.
Collapse
Affiliation(s)
- Kin Cheung Lo
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong.
| | - King In Hau
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong.
| | - Wai Kin Chan
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong.
| |
Collapse
|
41
|
Sierra MA, Sánchez D, Garrigues AR, Del Barco E, Wang L, Nijhuis CA. How to distinguish between interacting and noninteracting molecules in tunnel junctions. NANOSCALE 2018; 10:3904-3910. [PMID: 29423488 DOI: 10.1039/c7nr05739c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Recent experiments demonstrate a temperature control of the electric conduction through a ferrocene-based molecular junction. Here we examine the results in view of determining means to distinguish between transport through single-particle molecular levels or via transport channels split by Coulomb repulsion. Both transport mechanisms are similar in molecular junctions given the similarities between molecular intralevel energies and the charging energy. We propose an experimentally testable way to identify the main transport process. By applying a magnetic field to the molecule, we observe that an interacting theory predicts a shift of the conductance resonances of the molecule whereas in the noninteracting case each resonance is split into two peaks. The interaction model works well in explaining our experimental results obtained in a ferrocene-based single-molecule junction, where the charge degeneracy peaks shift (but do not split) under the action of an applied 7-Tesla magnetic field. This method is useful for a proper characterization of the transport properties of molecular tunnel junctions.
Collapse
Affiliation(s)
- Miguel A Sierra
- Institute for Cross-Disciplinary Physics and Complex Systems IFISC (UIB-CSIC), Palma de Mallorca, Spain.
| | | | | | | | | | | |
Collapse
|
42
|
|
43
|
Lambert CJ, Liu SX. A Magic Ratio Rule for Beginners: A Chemist's Guide to Quantum Interference in Molecules. Chemistry 2018; 24:4193-4201. [DOI: 10.1002/chem.201704488] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Indexed: 11/12/2022]
Affiliation(s)
- Colin J. Lambert
- Quantum Technology Centre, Physics Department; Lancaster University; Lancaster LA1 4YB UK
| | - Shi-Xia Liu
- Department of Chemistry and Biochemistry; University of Bern; Freiestrasse 3 3012 Bern Switzerland
| |
Collapse
|
44
|
Fan Y, Li HM, Zou GD, Zhang X, Pan YL, Cao KK, Zhang ML, Ma PL, Lu HT. Diferrocenes Bridged by a Geminal Diethynylethene Scaffold with Varying Pendant Substituents: Electronic Interactions in Cross-Conjugated System. Organometallics 2017. [DOI: 10.1021/acs.organomet.7b00686] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Yang Fan
- College of Chemistry
and Chemical Engineering, Xinyang Normal University, Xinyang 464000, People’s Republic of China
| | - Hua-Min Li
- College of Chemistry
and Chemical Engineering, Xinyang Normal University, Xinyang 464000, People’s Republic of China
| | - Guo-Dong Zou
- College of Chemistry
and Chemical Engineering, Xinyang Normal University, Xinyang 464000, People’s Republic of China
| | - Xu Zhang
- Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, People’s Republic of China
| | - Ying-Le Pan
- College of Chemistry
and Chemical Engineering, Xinyang Normal University, Xinyang 464000, People’s Republic of China
| | - Ke-Ke Cao
- College of Chemistry
and Chemical Engineering, Xinyang Normal University, Xinyang 464000, People’s Republic of China
| | - Meng-Li Zhang
- College of Chemistry
and Chemical Engineering, Xinyang Normal University, Xinyang 464000, People’s Republic of China
| | - Pei-Lin Ma
- College of Chemistry
and Chemical Engineering, Xinyang Normal University, Xinyang 464000, People’s Republic of China
| | - Hai-Ting Lu
- College of Chemistry
and Chemical Engineering, Xinyang Normal University, Xinyang 464000, People’s Republic of China
| |
Collapse
|
45
|
Chen S, Zhou W, Zhang Q, Kwok Y, Chen G, Ratner MA. Can Molecular Quantum Interference Effect Transistors Survive Vibration? J Phys Chem Lett 2017; 8:5166-5170. [PMID: 28974091 DOI: 10.1021/acs.jpclett.7b02214] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Quantum interference in cross-conjugated molecules can be utilized to construct molecular quantum interference effect transistors. However, whether its application can be achieved depends on the survivability of the quantum interference under real conditions such as nuclear vibration. We use two simulation methods to investigate the effects of nuclear vibration on quantum interference in a meta-linked benzene system. The simulation results suggest that the quantum interference is robust against nuclear vibration not only in the steady state but also in its transient dynamics, and thus the molecular quantum interference effect transistors can be realized.
Collapse
Affiliation(s)
- Shuguang Chen
- Department of Chemistry, The University of Hong Kong , Pokfulam Road, Hong Kong
| | - WeiJun Zhou
- Department of Chemistry, The University of Hong Kong , Pokfulam Road, Hong Kong
| | - Qing Zhang
- Department of Chemistry, The University of Hong Kong , Pokfulam Road, Hong Kong
| | - YanHo Kwok
- Department of Chemistry, The University of Hong Kong , Pokfulam Road, Hong Kong
| | - GuanHua Chen
- Department of Chemistry, The University of Hong Kong , Pokfulam Road, Hong Kong
| | - Mark A Ratner
- Department of Chemistry, Northwestern University , Evanston Illinois 60208, United States
| |
Collapse
|
46
|
Jeong H, Kim D, Xiang D, Lee T. High-Yield Functional Molecular Electronic Devices. ACS NANO 2017; 11:6511-6548. [PMID: 28578582 DOI: 10.1021/acsnano.7b02967] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
An ultimate goal of molecular electronics, which seeks to incorporate molecular components into electronic circuit units, is to generate functional molecular electronic devices using individual or ensemble molecules to fulfill the increasing technical demands of the miniaturization of traditional silicon-based electronics. This review article presents a summary of recent efforts to pursue this ultimate aim, covering the development of reliable device platforms for high-yield ensemble molecular junctions and their utilization in functional molecular electronic devices, in which distinctive electronic functionalities are observed due to the functional molecules. In addition, other aspects pertaining to the practical application of molecular devices such as manufacturing compatibility with existing complementary metal-oxide-semiconductor technology, their integration, and flexible device applications are also discussed. These advances may contribute to a deeper understanding of charge transport characteristics through functional molecular junctions and provide a desirable roadmap for future practical molecular electronics applications.
Collapse
Affiliation(s)
- Hyunhak Jeong
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University , Seoul 08826, Korea
| | - Dongku Kim
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University , Seoul 08826, Korea
| | - Dong Xiang
- Key Laboratory of Optical Information Science and Technology, Institute of Modern Optics, College of Electronic Information and Optical Engineering, Nankai University , Tianjin 300071, China
| | - Takhee Lee
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University , Seoul 08826, Korea
| |
Collapse
|
47
|
Kondo blockade due to quantum interference in single-molecule junctions. Nat Commun 2017; 8:15210. [PMID: 28492236 PMCID: PMC5437279 DOI: 10.1038/ncomms15210] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 03/06/2017] [Indexed: 11/08/2022] Open
Abstract
Molecular electronics offers unique scientific and technological possibilities, resulting from both the nanometre scale of the devices and their reproducible chemical complexity. Two fundamental yet different effects, with no classical analogue, have been demonstrated experimentally in single-molecule junctions: quantum interference due to competing electron transport pathways, and the Kondo effect due to entanglement from strong electronic interactions. Here we unify these phenomena, showing that transport through a spin-degenerate molecule can be either enhanced or blocked by Kondo correlations, depending on molecular structure, contacting geometry and applied gate voltages. An exact framework is developed, in terms of which the quantum interference properties of interacting molecular junctions can be systematically studied and understood. We prove that an exact Kondo-mediated conductance node results from destructive interference in exchange-cotunneling. Nonstandard temperature dependences and gate-tunable conductance peaks/nodes are demonstrated for prototypical molecular junctions, illustrating the intricate interplay of quantum effects beyond the single-orbital paradigm.
Collapse
|
48
|
Seth C, Kaliginedi V, Suravarapu S, Reber D, Hong W, Wandlowski T, Lafolet F, Broekmann P, Royal G, Venkatramani R. Conductance in a bis-terpyridine based single molecular breadboard circuit. Chem Sci 2017; 8:1576-1591. [PMID: 28451287 PMCID: PMC5359913 DOI: 10.1039/c6sc03204d] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 11/03/2016] [Indexed: 12/30/2022] Open
Abstract
Controlling charge flow in single molecule circuits with multiple electrical contacts and conductance pathways is a much sought after goal in molecular electronics. In this joint experimental and theoretical study, we advance the possibility of creating single molecule breadboard circuits through an analysis of the conductance of a bis-terpyridine based molecule (TP1). The TP1 molecule can adopt multiple conformations through relative rotations of 7 aromatic rings and can attach to electrodes in 61 possible single and multi-terminal configurations through 6 pyridyl groups. Despite this complexity, we show that it is possible to extract well defined conductance features for the TP1 breadboard and assign them rigorously to the underlying constituent circuits. Mechanically controllable break-junction (MCBJ) experiments on the TP1 molecular breadboard show an unprecedented 4 conductance states spanning a range 10 -2G0 to 10 -7G0. Quantitative theoretical examination of the conductance of TP1 reveals that combinations of 5 types of single terminal 2-5 ring subcircuits are accessed as a function of electrode separation to produce the distinct conductance steps observed in the MCBJ experiments. We estimate the absolute conductance for each single terminal subcircuit and its percentage contribution to the 4 experimentally observed conductance states. We also provide a detailed analysis of the role of quantum interference and thermal fluctuations in modulating conductance within the subcircuits of the TP1 molecular breadboard. Finally, we discuss the possible development of molecular circuit theory and experimental advances necessary for mapping conductance through complex single molecular breadboard circuits in terms of their constituent subcircuits.
Collapse
Affiliation(s)
- Charu Seth
- Department of Chemical Sciences , Tata Institute of Fundamental Research , Homi Bhabha Road, Colaba , Mumbai 400 005 , India .
| | - Veerabhadrarao Kaliginedi
- Department of Chemistry and Biochemistry , University of Bern , Freiestrasse 3, CH-3012 , Bern , Switzerland .
| | - Sankarrao Suravarapu
- Department of Chemistry and Biochemistry , University of Bern , Freiestrasse 3, CH-3012 , Bern , Switzerland .
| | - David Reber
- Department of Chemistry and Biochemistry , University of Bern , Freiestrasse 3, CH-3012 , Bern , Switzerland .
| | - Wenjing Hong
- Department of Chemical and Biochemical Engineering , College of Chemistry and Chemical Engineering , Xiamen University , Xiamen 361005 , China
| | - Thomas Wandlowski
- Department of Chemistry and Biochemistry , University of Bern , Freiestrasse 3, CH-3012 , Bern , Switzerland .
| | - Frédéric Lafolet
- Université Grenoble Alpes , Département de Chimie Moléculaire , UMR CNRS-5250 , Institut de Chimie Moléculaire de Grenoble , FR CNRS-2607 , BP 53 , 38041 Grenoble Cedex 9 , France .
| | - Peter Broekmann
- Department of Chemistry and Biochemistry , University of Bern , Freiestrasse 3, CH-3012 , Bern , Switzerland .
| | - Guy Royal
- Université Grenoble Alpes , Département de Chimie Moléculaire , UMR CNRS-5250 , Institut de Chimie Moléculaire de Grenoble , FR CNRS-2607 , BP 53 , 38041 Grenoble Cedex 9 , France .
| | - Ravindra Venkatramani
- Department of Chemical Sciences , Tata Institute of Fundamental Research , Homi Bhabha Road, Colaba , Mumbai 400 005 , India .
| |
Collapse
|
49
|
Bürkle M, Xiang L, Li G, Rostamian A, Hines T, Guo S, Zhou G, Tao N, Asai Y. The Orbital Selection Rule for Molecular Conductance as Manifested in Tetraphenyl-Based Molecular Junctions. J Am Chem Soc 2017; 139:2989-2993. [DOI: 10.1021/jacs.6b10837] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Marius Bürkle
- National Institute of Advanced Industrial Science and Technology (AIST), Research Center for Computational
Design of Advanced Functional Materials (CD-FMat), Central 2, Umezono 1-1-1, Tsukuba, Ibaraki 305-8568, Japan
| | - Limin Xiang
- Center for Bioelectronics and Biosensors,
Biodesign Institute, Arizona State University, Tempe, Arizona 85287, United States
| | - Guangfeng Li
- Laboratory of Advanced Materials, Fudan University, Shanghai 200438, P.R. China
| | - Ali Rostamian
- Center for Bioelectronics and Biosensors,
Biodesign Institute, Arizona State University, Tempe, Arizona 85287, United States
| | - Thomas Hines
- Center for Bioelectronics and Biosensors,
Biodesign Institute, Arizona State University, Tempe, Arizona 85287, United States
| | - Shaoyin Guo
- Center for Bioelectronics and Biosensors,
Biodesign Institute, Arizona State University, Tempe, Arizona 85287, United States
| | - Gang Zhou
- Laboratory of Advanced Materials, Fudan University, Shanghai 200438, P.R. China
| | - Nongjian Tao
- Center for Bioelectronics and Biosensors,
Biodesign Institute, Arizona State University, Tempe, Arizona 85287, United States
| | - Yoshihiro Asai
- National Institute of Advanced Industrial Science and Technology (AIST), Research Center for Computational
Design of Advanced Functional Materials (CD-FMat), Central 2, Umezono 1-1-1, Tsukuba, Ibaraki 305-8568, Japan
| |
Collapse
|
50
|
Su WX, Zuo X, Xie Z, Zhang GP, Wang CK. Obvious modulation of rectifying performance by conjugation breaking of the bridging fragment in donor–bridge–acceptor molecular diodes. RSC Adv 2017. [DOI: 10.1039/c7ra00254h] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Large modulation of rectifying performance is obtained by breaking conjugation of the bridging fragment in donor–bridge–acceptor molecular diodes.
Collapse
Affiliation(s)
- Wen-Xia Su
- Shandong Province Key Laboratory of Medical Physics and Image Processing Technology
- School of Physics and Electronics
- Shandong Normal University
- Jinan 250014
- China
| | - Xi Zuo
- Shandong Province Key Laboratory of Medical Physics and Image Processing Technology
- School of Physics and Electronics
- Shandong Normal University
- Jinan 250014
- China
| | - Zhen Xie
- Shandong Province Key Laboratory of Medical Physics and Image Processing Technology
- School of Physics and Electronics
- Shandong Normal University
- Jinan 250014
- China
| | - Guang-Ping Zhang
- Shandong Province Key Laboratory of Medical Physics and Image Processing Technology
- School of Physics and Electronics
- Shandong Normal University
- Jinan 250014
- China
| | - Chuan-Kui Wang
- Shandong Province Key Laboratory of Medical Physics and Image Processing Technology
- School of Physics and Electronics
- Shandong Normal University
- Jinan 250014
- China
| |
Collapse
|