1
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Bennett RX, Hendrickson JR, Bergfield JP. Quantum Interference Enhancement of the Spin-Dependent Thermoelectric Response. ACS NANO 2024; 18:11876-11885. [PMID: 38651504 PMCID: PMC11080465 DOI: 10.1021/acsnano.4c01297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 04/01/2024] [Accepted: 04/05/2024] [Indexed: 04/25/2024]
Abstract
We investigate the influence of quantum interference (QI) and broken spin-symmetry on the thermoelectric response of node-possessing junctions, finding a dramatic enhancement of the spin-thermopower (Ss), figure-of-merit (ZsT), and maximum thermodynamic efficiency (ηsmax) caused by destructive QI. Using many-body and single-particle methods, we calculate the response of 1,3-benzenedithiol and cross-conjugated molecule-based junctions subject to an applied magnetic field, finding nearly universal behavior over a range of junction parameters with Ss, ZsT, and reaching peak values of 2 π / 3 ( k / e ) , 1.51, and 28% of Carnot efficiency, respectively. We also find that the quantum-enhanced spin-response is spectrally broad, and the field required to achieve peak efficiency scales with temperature. The influence of off-resonant thermal channels (e.g., phonon heat transport) on this effect is also investigated.
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Affiliation(s)
- Runa X. Bennett
- Department
of Physics, Illinois State University, Normal, Illinois 61790, United States
| | - Joshua R. Hendrickson
- Air
Force Research Laboratory, Sensors Directorate, Wright-Patterson Air Force Base, Dayton, Ohio 45433, United States
| | - Justin P. Bergfield
- Department
of Physics, Illinois State University, Normal, Illinois 61790, United States
- Department
of Chemistry, Illinois State University, Normal, Illinois 61790, United States
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2
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Alves AL, Bernardino SV, Stadtlober CH, Girotto E, Farias G, do Nascimento RM, Curcio SF, Cazati T, Dotto MER, Eccher J, Furini LN, Gallardo H, Bock H, Bechtold IH. Charge carrier transport in perylene-based and pyrene-based columnar liquid crystals. Beilstein J Org Chem 2023; 19:1755-1765. [PMID: 38025088 PMCID: PMC10667716 DOI: 10.3762/bjoc.19.128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 10/31/2023] [Indexed: 12/01/2023] Open
Abstract
Electron and hole transport characteristics were evaluated for perylene-based and pyrene-based compounds using electron-only and hole-only devices. The perylene presented a columnar hexagonal liquid crystal phase at room temperature with strong molecular π-stacking inside the columns. The pyrene crystallizes bellow 166 °C, preserving the close-packed columnar rectangular structure of the mesophase. Photophysical analysis and numerical calculations assisted the interpretation of positive and negative charge carrier mobilities obtained from fitting the space charge limited regime of current vs voltage curves. The pyrene-based material demonstrated an electron mobility two orders of magnitude higher than the perylene one, indicating the potential of this class of materials as electron transporting layer.
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Affiliation(s)
- Alessandro L Alves
- Departamento de Física, Universidade Federal de Santa Catarina, Florianópolis 88040-900, SC, Brazil
| | - Simone V Bernardino
- Departamento de Física, Universidade Federal de Santa Catarina, Florianópolis 88040-900, SC, Brazil
| | - Carlos H Stadtlober
- Departamento de Física, Universidade Federal de Santa Catarina, Florianópolis 88040-900, SC, Brazil
| | - Edivandro Girotto
- Departamento de Química, Universidade Federal de Santa Catarina, Florianópolis 88040-900, SC, Brazil
| | - Giliandro Farias
- Departamento de Química, Universidade Federal de Santa Catarina, Florianópolis 88040-900, SC, Brazil
| | - Rodney M do Nascimento
- Departamento de Física, Universidade Federal de Santa Catarina, Florianópolis 88040-900, SC, Brazil
| | - Sergio F Curcio
- Departamento de Fisica, Universidade Federal de Ouro Preto, Ouro Preto 35400-000, MG, Brazil
| | - Thiago Cazati
- Departamento de Fisica, Universidade Federal de Ouro Preto, Ouro Preto 35400-000, MG, Brazil
| | - Marta E R Dotto
- Departamento de Física, Universidade Federal de Santa Catarina, Florianópolis 88040-900, SC, Brazil
| | - Juliana Eccher
- Departamento de Física, Universidade Federal de Santa Catarina, Florianópolis 88040-900, SC, Brazil
| | - Leonardo N Furini
- Departamento de Física, Universidade Federal de Santa Catarina, Florianópolis 88040-900, SC, Brazil
| | - Hugo Gallardo
- Departamento de Química, Universidade Federal de Santa Catarina, Florianópolis 88040-900, SC, Brazil
| | - Harald Bock
- Centre de Recherche Paul Pascal, CNRS, 115 av. Schweitzer, 33600 Pessac, France
| | - Ivan H Bechtold
- Departamento de Física, Universidade Federal de Santa Catarina, Florianópolis 88040-900, SC, Brazil
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3
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Bro-Jørgensen W, Solomon GC. Understanding Current Density in Molecules Using Molecular Orbitals. J Phys Chem A 2023; 127:9003-9012. [PMID: 37856785 PMCID: PMC10627148 DOI: 10.1021/acs.jpca.3c04631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 08/29/2023] [Indexed: 10/21/2023]
Abstract
While the use of molecular orbitals (MOs) and their isosurfaces to explain physical phenomena in chemical systems is a time-honored tool, we show that the nodes are an equally important component for understanding the current density through single-molecule junctions. We investigate three different model systems consisting of an alkane, alkene, and even [n]cumulene and show that we can explain the form of the current density using the MOs of the molecule. Essentially, the MOs define the region in which current can flow and their gradients define the direction in which current flows within that region. We also show that it is possible to simplify the current density for improved understanding by either partitioning the current density into more chemically intuitive parts, such as σ- and π-systems, or by filtering out MOs with negligible contributions to the overall current density. Our work highlights that it is possible to infer a non-equilibrium property (current density) given only equilibrium properties (MOs and their gradients), and this, in turn, grants deeper insight into coherent electron transport.
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Affiliation(s)
- William Bro-Jørgensen
- Department
of Chemistry and Nano-Science Center, University
of Copenhagen, Universitetsparken
5, DK-2100 Copenhagen, Denmark
| | - Gemma C. Solomon
- Department
of Chemistry and Nano-Science Center, University
of Copenhagen, Universitetsparken
5, DK-2100 Copenhagen, Denmark
- NNF
Quantum Computing Programme, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
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4
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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.
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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
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5
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Mang A, Rotthowe N, Beltako K, Linseis M, Pauly F, Winter RF. Single-molecule conductance studies on quasi- and metallaaromatic dibenzoylmethane coordination compounds and their aromatic analogs. NANOSCALE 2023; 15:5305-5316. [PMID: 36811332 DOI: 10.1039/d2nr05670d] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The ability to predict the conductive behaviour of molecules, connected to macroscopic electrodes, represents a crucial prerequisite for the design of nanoscale electronic devices. In this work, we investigate whether the notion of a negative relation between conductance and aromaticity (the so-called NRCA rule) also pertains to quasi-aromatic and metallaaromatic chelates derived from dibenzoylmethane (DBM) and Lewis acids (LAs) that either do or do not contribute two extra dπ electrons to the central resonance-stabilised β-ketoenolate binding pocket. We therefore synthesised a family of methylthio-functionalised DBM coordination compounds and subjected them, along with their truly aromatic terphenyl and 4,6-diphenylpyrimidine congeners, to scanning tunneling microscope break-junction (STM-BJ) experiments on gold nanoelectrodes. All molecules share the common motif of three π-conjugated, six-membered, planar rings with a meta-configuration at the central ring. According to our results, their molecular conductances fall within a factor of ca. 9 in an ordering aromatic < metallaaromatic < quasi-aromatic. The experimental trends are rationalised by quantum transport calculations based on density functional theory (DFT).
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Affiliation(s)
- André Mang
- Chemistry Department, University of Konstanz, 78457 Konstanz, Germany.
| | - Nils Rotthowe
- Chemistry Department, University of Konstanz, 78457 Konstanz, Germany.
| | - Katawoura Beltako
- Physics Department, University of Lomé, 1515 Lomé, Togo
- Institute of Physics, University of Augsburg, 86159 Augsburg, Germany.
| | - Michael Linseis
- Chemistry Department, University of Konstanz, 78457 Konstanz, Germany.
| | - Fabian Pauly
- Institute of Physics, University of Augsburg, 86159 Augsburg, Germany.
| | - Rainer F Winter
- Chemistry Department, University of Konstanz, 78457 Konstanz, Germany.
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6
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Ngue CM, Ho KF, Sainbileg B, Batsaikhan E, Hayashi M, Lee KY, Chen RS, Leung MK. Conductivity and photoconductivity in a two-dimensional zinc bis(triarylamine) coordination polymer. Chem Sci 2023; 14:1320-1328. [PMID: 36756319 PMCID: PMC9891455 DOI: 10.1039/d2sc06085j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 01/09/2023] [Indexed: 01/11/2023] Open
Abstract
We report the synthesis and characterization of a 2D semiconductive and photoconductive coordination polymer. [Zn(TPPB)(Cl2)]·H2O (1) (TPPB = N 1,N 1,N 4,N 4-tetrakis(4-(pyridin-4-yl)phenyl)benzene-1,4-diamine) consists of a TPPB redox-active linker with bis(triarylamine) as the core. It consists of two redox sites connected with a benzene ring as a bridge. Thus, this forms an extended conjugation pathway when the TPPB ligand is coordinated with the Zn2+ metal ions. The single crystal conductivity measurement revealed conductivity of 1 to be in the range of 0.83 to 1.9 S cm-1. Band structure analysis predicted that 1 is a semiconductor from the delocalization of electronic transport in the network. The computational calculations show the difference in charge distribution between holes and electrons, which led to spatial separation. This implies a long charge carrier lifetime as indicated by lifetime measurement. Incorporating a bis(triarylamine)-based redox-active linker could lead to a new semiconductive scaffold material with photocatalytic applications.
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Affiliation(s)
- Chin May Ngue
- Department of Chemistry, National Taiwan University Taipei 106 Taiwan
| | - Kuan Fu Ho
- Graduate Institute of Electro-Optical Engineering, National Taiwan University of Science and TechnologyTaipei 106Taiwan
| | - Batjargal Sainbileg
- Center for Condensed Matter Sciences, Center of Atomic Initiative for New Materials, National Taiwan UniversityTaipei 106Taiwan
| | - Erdembayalag Batsaikhan
- Center for Condensed Matter Sciences, Center of Atomic Initiative for New Materials, National Taiwan UniversityTaipei 106Taiwan
| | - Michitoshi Hayashi
- Center for Condensed Matter Sciences, Center of Atomic Initiative for New Materials, National Taiwan UniversityTaipei 106Taiwan
| | - Kuei Yi Lee
- Graduate Institute of Electro-Optical Engineering, National Taiwan University of Science and TechnologyTaipei 106Taiwan
| | - Ruei San Chen
- Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology Taipei 106 Taiwan
| | - Man Kit Leung
- Department of Chemistry, National Taiwan University Taipei 106 Taiwan
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7
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Okazawa K, Tsuji Y, Yoshizawa K. Graph-theoretical exploration of the relation between conductivity and connectivity in heteroatom-containing single-molecule junctions. J Chem Phys 2022; 156:091102. [DOI: 10.1063/5.0083486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Kazuki Okazawa
- Institute for Materials Chemistry and Engineering, Kyushu University - Ito Campus, Japan
| | - Yuta Tsuji
- Institute for Materials Chemistry and Engineering, Kyushu Daigaku, Japan
| | - Kazunari Yoshizawa
- Institute for Materials Chemistry and Engineering, Kyushu University, Japan
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8
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Pitié S, Seydou M, Dappe YJ, Martin P, Maurel F, Lacroix JC. Insights on asymmetric BTB-based molecular junctions: Effect of electrode coupling. Chem Phys Lett 2022. [DOI: 10.1016/j.cplett.2021.139273] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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9
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Garner MH, Solomon GC. Simultaneous Suppression of π- and σ-Transmission in π-Conjugated Molecules. J Phys Chem Lett 2020; 11:7400-7406. [PMID: 32787288 DOI: 10.1021/acs.jpclett.0c01727] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Molecular dielectric materials require ostensibly conflicting requirements of high polarizability and low conductivity. As previous efforts toward molecular insulators focused on saturated molecules, it remains an open question whether π- and σ-transport can be simultaneously suppressed in conjugated systems. Here, we demonstrate that there are conjugated molecules where the σ-transmission is suppressed by destructive σ-interference, while the π-transmission can be suppressed by a localized disruption of conjugation. Using density functional theory, we study the Landauer transmission and ballistic current density, which allow us to determine how the transmission is affected by various structural changes in the molecule. We find that in para-linked oligophenyl rings the σ-transmission can be suppressed by changing the remaining hydrogens to methyl groups due to the inherent gauche-like structure of the carbon backbone within a benzene ring, similar to what was previously seen in saturated systems. At the same time, the methyl groups fulfill a dual purpose as they modulate the twist angle between neighboring phenyl rings. When neighboring rings are orthogonal to each other, the transmission through both π- and σ-systems is effectively suppressed. Alternatively, breaking conjugation in a single phenyl ring by saturating two carbons atoms with two methyl substituents on each carbon, results in suppressed π- and σ-transport independent of dihedral angle. These two strategies demonstrate that methyl-substituted oligophenyls are promising candidates for the development of molecular dielectric materials.
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Affiliation(s)
- Marc H Garner
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
| | - Gemma C Solomon
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
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10
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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.
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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
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11
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Shultz DA, Kirk ML, Zhang J, Stasiw DE, Wang G, Yang J, Habel-Rodriguez D, Stein BW, Sommer RD. Spectroscopic Signatures of Resonance Inhibition Reveal Differences in Donor-Bridge and Bridge-Acceptor Couplings. J Am Chem Soc 2020; 142:4916-4924. [PMID: 32069027 DOI: 10.1021/jacs.0c00326] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The torsional dependence of the ground state magnetic exchange coupling (J) and the corresponding electronic coupling matrix element (HDA) for eight transition metal complexes possessing donor-acceptor (D-A) biradical ligands is presented. These biradical ligands are composed of an S = 1/2 metal semiquinone (SQ) donor and an S = 1/2 nitronylnitroxide (NN) acceptor, which are coupled to each other via para-phenylene, methyl-substituted para-phenylenes, or a bicyclo[2.2.2]octane ring. The observed trends in electronic absorption and resonance Raman spectral features are in accord with a reduction in electronic and magnetic coupling between D and A units within the framework of our valence bond configuration interaction model. Moreover, our spectroscopic results highlight different orbital mechanisms that modulate coupling in these complexes, which is not manifest in the ferromagnetic JSQ-B-NN values. The work provides new detailed insight into the effects of torsional rotations which contribute to inhomogeneities in experimentally determined exchange couplings, electron transfer rates, and electron transport conductance measurements.
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Affiliation(s)
- David A Shultz
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Martin L Kirk
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, New Mexico 87131-0001, United States.,Center for High Technology Materials, The University of New Mexico, Albuquerque, New Mexico 87106, United States
| | - Jinyuan Zhang
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Daniel E Stasiw
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Guangbin Wang
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Jing Yang
- Department of Chemistry, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, New Mexico 87131-0001, United States
| | - Diana Habel-Rodriguez
- Department of Chemistry, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, New Mexico 87131-0001, United States
| | - Benjamin W Stein
- Department of Chemistry, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, New Mexico 87131-0001, United States
| | - Roger D Sommer
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
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12
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Jones LO, Mosquera MA, Fu B, Schatz GC, Marks TJ, Ratner MA. Quantum Interference and Substantial Property Tuning in Conjugated Z- ortho-Regio-Resistive Organic (ZORRO) Junctions. NANO LETTERS 2019; 19:8956-8963. [PMID: 31682761 DOI: 10.1021/acs.nanolett.9b03849] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Coherence is a significant factor in nanoscale electronic insulator technology and necessitates an understanding of the structure-property relationship between constructive and destructive quantum interference. This is particularly important in organic dielectric circuitry, which is the subject of this work. It is known that molecular wires composed of (i) meta-substituted phenylene rings, (ii) cross-conjugated double bonds (orthogonal to the molecular long axis), and (iii) single bonds can dramatically reduce electrical transmission. Here we add to these tools the use of an unexplored molecular shape to create strong and counterintuitive interference: a fully conjugated molecular wire with a structure that is forced back on itself in a Z shape, thereby exhibiting remarkably low conductance (G = 0.43 × 10-9 S) even though the phenylene arrangements are ortho- rather than meta-disposed. We call these Z-shaped molecules having ultralow conduction Z-ortho-regio-resistive organics (ZORROs). Here we analyze a series of ZORRO molecules and find them to have significant insulating properties in the coherent electron-transport regime due to interfering transmission pathways in the phenylene rings. Importantly, we find that both electron-withdrawing (fluorine) and electron-donating (methoxy) substituents enhance the transmission, which is not desirable. The former is due to the suppression of the destructive quantum interference at the F site, thereby enhancing the overall transmission, much like a Büttiker probe. The latter is due to a methoxy unit resonance additive effect, akin to oxygen doping, and positively contributes to the transmission. We then examine the effects of replacing the phenylene rings with 4,5- and 3,4-disubstituted thiophenes and how this ZORRO modification further reduces the transmission. An ultralow conductance of 0.13 × 10-9 S and a relatively high dielectric constant (εr) of ∼5 are predicted for the 3,4-thiophene ZORRO derivative, which closely resembles two cross-conjugated units, making it an intriguing candidate for a gate dielectric material.
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Affiliation(s)
- Leighton O Jones
- Department of Chemistry and the Materials Research Center , Northwestern University , Evanston , Illinois 60208 , United States
| | - Martín A Mosquera
- Department of Chemistry and the Materials Research Center , Northwestern University , Evanston , Illinois 60208 , United States
| | - Bo Fu
- Department of Chemistry and the Materials Research Center , Northwestern University , Evanston , Illinois 60208 , United States
| | - George C Schatz
- Department of Chemistry and the Materials Research Center , Northwestern University , Evanston , Illinois 60208 , United States
| | - Tobin J Marks
- Department of Chemistry and the Materials Research Center , Northwestern University , Evanston , Illinois 60208 , United States
| | - Mark A Ratner
- Department of Chemistry and the Materials Research Center , Northwestern University , Evanston , Illinois 60208 , United States
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13
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Herrmann C. Electronic Communication as a Transferable Property of Molecular Bridges? J Phys Chem A 2019; 123:10205-10223. [PMID: 31380640 DOI: 10.1021/acs.jpca.9b05618] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Electronic communication through molecular bridges is important for different types of experiments, such as single-molecule conductance, electron transfer, superexchange spin coupling, and intramolecular singlet fission. In many instances, the chemical structure of the bridge determines how the two parts it is connecting communicate, and does so in ways that are transferable between these different manifestations (for example, high conductance often correlates with strong antiferromagnetic spin coupling, and low conductance due to destructive quantum interference correlates with ferromagnetic coupling). Defining electronic communication as a transferable property of the bridge can help transfer knowledge between these different areas of research. Examples and limits of such transferability are discussed here, along with some possible directions for future research, such as employing spin-coupled and mixed-valence systems as structurally well-controlled proxies for understanding molecular conductance and for validating first-principles theoretical methodologies, building conceptual understanding for the growing experimental work on intramolecular singlet fission, and developing measures for the transferability of electronic communication as a bridge property.
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Affiliation(s)
- Carmen Herrmann
- Department of Chemistry , University of Hamburg , Martin-Luther-King-Platz 6 , Hamburg 20146 , Germany
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14
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Tsuji Y, Estrada E. Influence of long-range interactions on quantum interference in molecular conduction. A tight-binding (Hückel) approach. J Chem Phys 2019; 150:204123. [PMID: 31153184 DOI: 10.1063/1.5097330] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
When certain pairs of atoms in a π-conjugated molecule are connected with nanometer-scale source and drain electrodes, the remarkable quantum interference (QI) effect may arise. In this case, the electron transmission probability is significantly suppressed due to the QI effect. Tight-binding approaches, such as the Hückel molecular orbital (HMO) model, have revealed important features of this quantum phenomenon. However, important deviations from experiments and from more sophisticated calculations are known for a variety of cases. Here, we propose an extension of the HMO method to include non-nearest-neighbor interactions. Such long-range interactions (LRIs) are implemented in the HMO model in the form of a damping function that decays as the topological distance-the number of bonds separating two atoms-gets larger. The proposed model is further developed so that a geometric modification, i.e., the rotation around a single bond, can be taken into account. Our results show that LRI affects both the location of the antiresonance peak due to QI and the intensity of QI, even suppressing it in some cases. These results agree well with what was observed in a Density Functional based Tight-Binding (DFTB) study reported in the literature. These properties can be interpreted on the basis of a graph-theoretic path-counting model as well as the molecular orbital theory. In addition, the geometric LRI model is shown to reproduce the change of transmission as a function of rotation around the single bond separating two benzene rings in biphenyl, in agreement with what was observed in both experiment and DFTB calculation.
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Affiliation(s)
- Yuta Tsuji
- Institute for Materials Chemistry and Engineering and IRCCS, Kyushu University, Nishi-ku, Fukuoka 819-0395, Japan
| | - Ernesto Estrada
- Institute of Mathematics and Applications (IUMA), Universidad de Zaragoza, Pedro Cerbuna 12, E-50009 Zaragoza, Spain
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15
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Fung ED, Gelbwaser D, Taylor J, Low J, Xia J, Davydenko I, Campos LM, Marder S, Peskin U, Venkataraman L. Breaking Down Resonance: Nonlinear Transport and the Breakdown of Coherent Tunneling Models in Single Molecule Junctions. NANO LETTERS 2019; 19:2555-2561. [PMID: 30821465 DOI: 10.1021/acs.nanolett.9b00316] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The promise of the field of single-molecule electronics is to reveal a new class of quantum devices that leverages the strong electronic interactions inherent to subnanometer scale systems. Here, we form Au-molecule-Au junctions using a custom scanning tunneling microscope and explore charge transport through current-voltage measurements. We focus on the resonant tunneling regime of two molecules, one that is primarily an electron conductor and one that conducts primarily holes. We find that in the high bias regime, junctions that do not rupture demonstrate reproducible and pronounced negative differential resistance (NDR)-like features followed by hysteresis with peak-to-valley ratios exceeding 100 in some cases. Furthermore, we show that both junction rupture and NDR are induced by charging of the molecular orbital dominating transport and find that the charging is reversible at lower bias and with time with kinetic time scales on the order of hundreds of milliseconds. We argue that these results cannot be explained by existing models of charge transport and likely require theoretical advances describing the transition from coherent to sequential tunneling. Our work also suggests new rules for operating single-molecule devices at high bias to obtain highly nonlinear behavior.
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Affiliation(s)
- E-Dean Fung
- Department of Applied Physics and Applied Mathematics , Columbia University , New York , New York 10027 , United States
| | - David Gelbwaser
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 United States
| | - Jeffrey Taylor
- Department of Applied Physics and Applied Mathematics , Columbia University , New York , New York 10027 , United States
| | - Jonathan Low
- Department of Chemistry , Columbia University , New York , New York 10027 , United States
| | - Jianlong Xia
- School of Chemistry, Chemical Engineering, and Life Science , Wuhan University of Technology , Wuhan 430070 , China
| | - Iryna Davydenko
- School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics , Georgia Institute of Technology , Atlanta , Georgia 30332-0400 , United States
| | - Luis M Campos
- Department of Chemistry , Columbia University , New York , New York 10027 , United States
| | - Seth Marder
- School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics , Georgia Institute of Technology , Atlanta , Georgia 30332-0400 , United States
| | - Uri Peskin
- Schulich Faculty of Chemistry , Technion-Israel Institute of Technology , Haifa 32000 , Israel
| | - Latha Venkataraman
- Department of Applied Physics and Applied Mathematics , Columbia University , New York , New York 10027 , United States
- Department of Chemistry , Columbia University , New York , New York 10027 , United States
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16
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Wang K, Vezzoli A, Grace IM, McLaughlin M, Nichols RJ, Xu B, Lambert CJ, Higgins SJ. Charge transfer complexation boosts molecular conductance through Fermi level pinning. Chem Sci 2019; 10:2396-2403. [PMID: 30881668 PMCID: PMC6385675 DOI: 10.1039/c8sc04199g] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 01/02/2019] [Indexed: 11/21/2022] Open
Abstract
Interference features in the transmission spectra can dominate charge transport in metal-molecule-metal junctions when they occur close to the contact Fermi energy (E F). Here, we show that by forming a charge-transfer complex with tetracyanoethylene (TCNE) we can introduce new constructive interference features in the transmission profile of electron-rich, thiophene-based molecular wires that almost coincide with E F. Complexation can result in a large enhancement of junction conductance, with very efficient charge transport even at relatively large molecular lengths. For instance, we report a conductance of 10-3 G 0 (∼78 nS) for the ∼2 nm long α-quaterthiophene:TCNE complex, almost two orders of magnitude higher than the conductance of the bare molecular wire. As the conductance of the complexes is remarkably independent of features such as the molecular backbone and the nature of the contacts to the electrodes, our results strongly suggest that the interference features are consistently pinned near to the Fermi energy of the metallic leads. Theoretical studies indicate that the semi-occupied nature of the charge-transfer orbital is not only important in giving rise to the latter effect, but also could result in spin-dependent transport for the charge-transfer complexes. These results therefore present a simple yet effective way to increase charge transport efficiency in long and poorly conductive molecular wires, with important repercussions in single-entity thermoelectronics and spintronics.
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Affiliation(s)
- Kun Wang
- Department of Physics and Astronomy & NanoSEC , University of Georgia , 220 Riverbend Road , Athens , GA 30602 , USA .
| | - Andrea Vezzoli
- Department of Chemistry , University of Liverpool , Crown Street , Liverpool L69 7ZD , UK .
| | - Iain M Grace
- Department of Physics , Lancaster University , Lancaster LA1 4YB , UK .
| | - Maeve McLaughlin
- Department of Chemistry , University of Liverpool , Crown Street , Liverpool L69 7ZD , UK .
| | - Richard J Nichols
- Department of Chemistry , University of Liverpool , Crown Street , Liverpool L69 7ZD , UK .
| | - Bingqian Xu
- Department of Physics and Astronomy & NanoSEC , University of Georgia , 220 Riverbend Road , Athens , GA 30602 , USA .
- College of Engineering & NanoSEC , University of Georgia , 220 Riverbend Road , Athens , GA 30602 , USA
| | - Colin J Lambert
- Department of Physics , Lancaster University , Lancaster LA1 4YB , UK .
| | - Simon J Higgins
- Department of Chemistry , University of Liverpool , Crown Street , Liverpool L69 7ZD , UK .
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17
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Gryn'ova G, Corminboeuf C. Topology-Driven Single-Molecule Conductance of Carbon Nanothreads. J Phys Chem Lett 2019; 10:825-830. [PMID: 30668127 DOI: 10.1021/acs.jpclett.8b03556] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Highly conductive single-molecule junctions typically involve π-conjugated molecular bridges, whose frontier molecular orbital energy levels can be fine-tuned to best match the Fermi level of the leads. Fully saturated wires, e.g., alkanes, are typically thought of as insulating rather than highly conductive. However, in this work, we demonstrate in silico that significant zero-bias conductance can be achieved in such systems by means of topology. Specifically, caged saturated hydrocarbons offering multiple σ-conductance channels afford transmission far beyond what could be expected based upon conventional superposition laws, particularly if these pathways are composed entirely from quaternary carbon atoms. Computed conductance of molecular bridges based on carbon nanothreads, e.g., polytwistane, is not only of appreciable magnitude; it also shows a very slow decay with increasing nanogap, similarly to the case of π-conjugated wires. These findings offer a way to manipulate the transport properties of molecular systems by means of their topology, alternatively to the traditionally invoked electronic structure.
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Affiliation(s)
- Ganna Gryn'ova
- Laboratory for Computational Molecular Design, Institute of Chemical Sciences and Engineering , École Polytechnique Fédérale de Lausanne , CH-1015 Lausanne , Switzerland
| | - Clémence Corminboeuf
- Laboratory for Computational Molecular Design, Institute of Chemical Sciences and Engineering , École Polytechnique Fédérale de Lausanne , CH-1015 Lausanne , Switzerland
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18
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Garner MH, Koerstz M, Jensen JH, Solomon GC. The Bicyclo[2.2.2]octane Motif: A Class of Saturated Group 14 Quantum Interference Based Single-Molecule Insulators. J Phys Chem Lett 2018; 9:6941-6947. [PMID: 30484655 DOI: 10.1021/acs.jpclett.8b03432] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The electronic transmission through σ-conjugated molecules can be fully suppressed by destructive quantum interference, which makes them potential candidates for single-molecule insulators. The first molecule with clear suppression of the single-molecule conductance due to σ-interference was recently found in the form of a functionalized bicyclo[2.2.2]octasilane. Here we continue the search for potential single-molecule insulators based on saturated group 14 molecules. Using a high-throughput screening approach, we assess the electron transport properties of the bicyclo[2.2.2]octane class by systematically varying the constituent atoms between carbon, silicon, and germanium, thus exploring the full chemical space of 771 different molecules. The majority of the molecules in the bicyclo[2.2.2]octane class are found to be highly insulating molecules. Though the all-silicon molecule is a clear-cut case of σ-interference, it is not unique within its class and there are many potential molecules that we predict to be more insulating. The finding of this class of quantum interference based single-molecule insulators indicates that a broad range of highly insulating saturated group 14 molecules are likely to exist.
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19
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Schäfer J, Holzapfel M, Schmiedel A, Steiner UE, Lambert C. Fine tuning of electron transfer and spin chemistry parameters in triarylamine-bridge-naphthalene diimide dyads by bridge substituents. Phys Chem Chem Phys 2018; 20:27093-27104. [PMID: 30334029 DOI: 10.1039/c8cp04910f] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The photoinduced charge separation and charge recombination in a set of four molecular dyads consisting of a triarylamine donor and a naphthalene diimide acceptor were investigated by time resolved transient absorption spectroscopy with fs and ns time resolution. In these dyads the donor and acceptor are bridged by a meta-conjugated diethynylbenzene bridge whose electronic nature was tuned by small electron donating (OMe, Me) or electron withdrawing (Cl, CN) substituents. While the formation of the transient charge separated states is complete within tens of ps, charge recombination is biphasic with a shorter component of several hundred ns and a longer component of several microseconds. This behaviour could be rationalized by assuming an equilibrium of singlet and triplet charge separated states. Magnetic field dependent measurements showed a strong influence on the biphasic decay kinetics and also a pronounced level crossing effect in the magnetic field affected reaction yield (MARY) spectra caused by a significant exchange coupling. An analysis of the observed kinetics using classical kinetic rate equations yields rate constants for charge separation and charge recombination as well as the exchange interaction splitting in the radical ion pair, all of them showing a delicate dependence on the bridge substituents.
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Affiliation(s)
- Julian Schäfer
- Institut für Organische Chemie and Center for Nanosystems Chemistry, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
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20
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Makhoul R, Gluyas JBG, Vincent KB, Sahnoune H, Halet JF, Low PJ, Hamon JR, Lapinte C. Redox Properties of Ferrocenyl Ene-diynyl-Bridged Cp*(dppe)M–C≡C–1,4-(C6H4) Complexes. Organometallics 2018. [DOI: 10.1021/acs.organomet.8b00740] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Rim Makhoul
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes)-UMR 6226, F-35000 Rennes, France
| | - Josef B. G. Gluyas
- School of Molecular Sciences, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
| | - Kevin B. Vincent
- Department of Chemistry, Durham University, South Road, Durham DH1 3LE, U.K
| | - Hiba Sahnoune
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes)-UMR 6226, F-35000 Rennes, France
- Département de Chimie, Faculté des Sciences, Université M’Hamed Bougara, Boumerdès, Algeria
| | - Jean-François Halet
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes)-UMR 6226, F-35000 Rennes, France
| | - Paul J. Low
- School of Molecular Sciences, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
| | - Jean-René Hamon
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes)-UMR 6226, F-35000 Rennes, France
| | - Claude Lapinte
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes)-UMR 6226, F-35000 Rennes, France
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21
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Fias S, Stuyver T. Extension of the source-sink potential approach to Hartree-Fock and density functional theory: A new tool to visualize the ballistic current through molecules. J Chem Phys 2017; 147:184102. [DOI: 10.1063/1.5001924] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- Stijn Fias
- Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4M1, Canada
- General Chemistry (ALGC), Free University Brussels (VUB), Pleinlaan 2, B1050 Brussels, Belgium
| | - Thijs Stuyver
- General Chemistry (ALGC), Free University Brussels (VUB), Pleinlaan 2, B1050 Brussels, Belgium
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22
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Stuyver T, Blotwijk N, Fias S, Geerlings P, De Proft F. Exploring Electrical Currents through Nanographenes: Visualization and Tuning of the through-Bond Transmission Paths. Chemphyschem 2017; 18:3012-3022. [DOI: 10.1002/cphc.201700874] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 08/15/2017] [Indexed: 12/22/2022]
Affiliation(s)
- Thijs Stuyver
- Algemene Chemie; Vrije Universiteit Brussel; Pleinlaan 2 1050 Brussels Belgium) (Member of the QCMM Ghent-Brussels Alliance Group
- Research Foundation-Flanders (FWO-Vlaanderen); Egmontstraat 5 1000 Brussels Belgium
| | - Nathalie Blotwijk
- Algemene Chemie; Vrije Universiteit Brussel; Pleinlaan 2 1050 Brussels Belgium) (Member of the QCMM Ghent-Brussels Alliance Group
| | - Stijn Fias
- Algemene Chemie; Vrije Universiteit Brussel; Pleinlaan 2 1050 Brussels Belgium) (Member of the QCMM Ghent-Brussels Alliance Group
| | - Paul Geerlings
- Algemene Chemie; Vrije Universiteit Brussel; Pleinlaan 2 1050 Brussels Belgium) (Member of the QCMM Ghent-Brussels Alliance Group
| | - Frank De Proft
- Algemene Chemie; Vrije Universiteit Brussel; Pleinlaan 2 1050 Brussels Belgium) (Member of the QCMM Ghent-Brussels Alliance Group
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23
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Kirk ML, Shultz DA, Zhang J, Dangi R, Ingersol L, Yang J, Finney NS, Sommer RD, Wojtas L. Heterospin biradicals provide insight into molecular conductance and rectification. Chem Sci 2017; 8:5408-5415. [PMID: 28970920 PMCID: PMC5609533 DOI: 10.1039/c7sc00073a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 05/12/2017] [Indexed: 01/09/2023] Open
Abstract
The correlation of electron transfer with molecular conductance (g: electron transport through single molecules) by Nitzan and others has contributed to a fundamental understanding of single-molecule electronic materials. When an unsymmetric, dipolar molecule spans two electrodes, the possibility exists for different conductance values at equal, but opposite electrode biases. In the device configuration, these molecules serve as rectifiers of the current and the efficiency of the device is given by the rectification ratio (RR = gforward/greverse). Experimental determination of the RR is challenging since the orientation of the rectifying molecule with respect to the electrodes and with respect to the electrode bias direction is difficult to establish. Thus, while two different values of g can be measured and a RR calculated, one cannot easily assign each conductance value as being aligned with or opposed to the molecular dipole, and calculations are often required to resolve the uncertainty. Herein, we describe the properties of two isomeric, triplet ground state biradical molecules that serve as constant-bias analogs of single-molecule electronic devices. Through established theoretical relationships between g and electronic coupling, H2, and between H2 and magnetic exchange coupling, J (g ∝ H2 ∝ J), we use the ratio of experimental J-values for our two isomers to calculate a RR for an unsymmetric bridge molecule with known geometry relative to the two radical fragments of the molecule and at a spectroscopically-defined potential bias. Our experimental results are compared with device transport calculations.
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Affiliation(s)
- Martin L Kirk
- The University of New Mexico , MSC03 2060, 1 University of New Mexico , Albuquerque , New Mexico 87131-0001 , USA .
| | - David A Shultz
- Department of Chemistry , North Carolina State University , Raleigh , North Carolina 27695-8204 , USA .
| | - Jinyuan Zhang
- Department of Chemistry , North Carolina State University , Raleigh , North Carolina 27695-8204 , USA .
| | - Ranjana Dangi
- The University of New Mexico , MSC03 2060, 1 University of New Mexico , Albuquerque , New Mexico 87131-0001 , USA .
| | - Laura Ingersol
- The University of New Mexico , MSC03 2060, 1 University of New Mexico , Albuquerque , New Mexico 87131-0001 , USA .
| | - Jing Yang
- The University of New Mexico , MSC03 2060, 1 University of New Mexico , Albuquerque , New Mexico 87131-0001 , USA .
| | - Nathaniel S Finney
- School of Pharmaceutical Science and Technology , Tianjin University , 505/Building 24, 92 Weijin Road, Nankai District , Tianjin , 300072 , P. R. China
| | - Roger D Sommer
- Department of Chemistry , North Carolina State University , Raleigh , North Carolina 27695-8204 , USA .
| | - Lukasz Wojtas
- Department of Chemistry , University of South Florida , 4202 E. Fowler Avenue , CHE 205 Tampa , FL 33620-5250 , USA
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24
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Schäfer J, Holzapfel M, Mladenova B, Kattnig D, Krummenacher I, Braunschweig H, Grampp G, Lambert C. Hole Transfer Processes in meta- and para-Conjugated Mixed Valence Compounds: Unforeseen Effects of Bridge Substituents and Solvent Dynamics. J Am Chem Soc 2017; 139:6200-6209. [DOI: 10.1021/jacs.7b01650] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Julian Schäfer
- Institut
für Organische Chemie and Center for Nanosystems Chemistry, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Marco Holzapfel
- Institut
für Organische Chemie and Center for Nanosystems Chemistry, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Boryana Mladenova
- Institute
of Physical and Theoretical Chemistry, Graz University of Technology, Stremayrgasse 9, A-8010 Graz, Austria
| | - Daniel Kattnig
- Physical
and Theoretical Chemistry Laboratory, University of Oxford, South Parks
Road, Oxford, OX1 3QZ, U.K
| | - Ivo Krummenacher
- Institut
für Anorganische Chemie, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Holger Braunschweig
- Institut
für Anorganische Chemie, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Günter Grampp
- Institute
of Physical and Theoretical Chemistry, Graz University of Technology, Stremayrgasse 9, A-8010 Graz, Austria
| | - Christoph Lambert
- Institut
für Organische Chemie and Center for Nanosystems Chemistry, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
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25
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Gryn'ova G, Ollitrault PJ, Corminboeuf C. Guidelines and diagnostics for charge carrier tuning in thiophene-based wires. Phys Chem Chem Phys 2017; 19:23254-23259. [DOI: 10.1039/c7cp04295g] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Reported experimental trends in charge carrier tuning in single molecule junctions of oligothiophene-based wires are rationalized by means of frontier molecular orbital theory.
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Affiliation(s)
- Ganna Gryn'ova
- Institut des Sciences et Ingénierie Chimiques, École polytechnique fédérale de Lausanne
- CH-1015 Lausanne
- Switzerland
| | - Pauline J. Ollitrault
- Institut des Sciences et Ingénierie Chimiques, École polytechnique fédérale de Lausanne
- CH-1015 Lausanne
- Switzerland
| | - Clémence Corminboeuf
- Institut des Sciences et Ingénierie Chimiques, École polytechnique fédérale de Lausanne
- CH-1015 Lausanne
- Switzerland
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26
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Frisenda R, Harzmann GD, Celis Gil JA, Thijssen JM, Mayor M, van der Zant HSJ. Stretching-Induced Conductance Increase in a Spin-Crossover Molecule. NANO LETTERS 2016; 16:4733-7. [PMID: 27088578 DOI: 10.1021/acs.nanolett.5b04899] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We investigate transport through mechanically triggered single-molecule switches that are based on the coordination sphere-dependent spin state of Fe(II)-species. In these molecules, in certain junction configurations the relative arrangement of two terpyridine ligands within homoleptic Fe(II)-complexes can be mechanically controlled. Mechanical pulling may thus distort the Fe(II) coordination sphere and eventually modify their spin state. Using the movable nanoelectrodes in a mechanically controlled break-junction at low temperature, current-voltage measurements at cryogenic temperatures support the hypothesized switching mechanism based on the spin-crossover behavior. A large fraction of molecular junctions formed with the spin-crossover-active Fe(II)-complex displays a conductance increase for increasing electrode separation and this increase can reach 1-2 orders of magnitude. Theoretical calculations predict a stretching-induced spin transition in the Fe(II)-complex and a larger transmission for the high-spin configuration.
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Affiliation(s)
- Riccardo Frisenda
- Kavli Institute of Nanoscience, Delft University of Technology , 2600 GA Delft, The Netherlands
| | | | - Jose A Celis Gil
- Kavli Institute of Nanoscience, Delft University of Technology , 2600 GA Delft, The Netherlands
| | - Joseph M Thijssen
- Kavli Institute of Nanoscience, Delft University of Technology , 2600 GA Delft, The Netherlands
| | - Marcel Mayor
- University of Base l, 4056 Basel, Switzerland
- Karlsruhe Institute of Technology (KIT) , P.O. Box 3640, 76021 Karlsruhe, Germany
- Lehn Institute of Functional Materials (LIFM), Sun Yat-Sen University (SYSU) , Gunagzhou, China
| | - Herre S J van der Zant
- Kavli Institute of Nanoscience, Delft University of Technology , 2600 GA Delft, The Netherlands
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27
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Shameem MA, Esfandiarfard K, Öberg E, Ott S, Orthaber A. Direct, Sequential, and Stereoselective Alkynylation of C,C-Dibromophosphaalkenes. Chemistry 2016; 22:10614-9. [PMID: 27310813 DOI: 10.1002/chem.201601955] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Indexed: 01/07/2023]
Abstract
The first direct alkynylation of C,C-dibromophosphaalkenes by a reaction with sulfonylacetylenes is reported. Alkynylation proceeds selectively in the trans position relative to the P substituent to afford bromoethynylphosphaalkenes. Owing to the absence of transition metals in the procedure, the previously observed conversion of dibromophosphaalkenes into phosphaalkynes through the phosphorus analog of the Fritsch-Buttenberg-Wiechell rearrangement is thus suppressed. The bromoethynylphosphaalkenes can subsequently be converted to C,C-diacetylenic, cross-conjugated phosphaalkenes by following a Sonogashira coupling protocol in good overall yields. By using the newly described method, full control over the stereochemistry at the P=C double bond is achieved. The substrate scope of this reaction is demonstrated for different dibromophosphaalkenes as well as different sulfonylacetylenes.
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Affiliation(s)
- Muhammad A Shameem
- Department of Chemistry - Ångström Laboratories, Molecular Inorganic Chemistry, Uppsala University, Box 523, 75120, Uppsala, Sweden
| | - Keyhan Esfandiarfard
- Department of Chemistry - Ångström Laboratories, Molecular Inorganic Chemistry, Uppsala University, Box 523, 75120, Uppsala, Sweden
| | - Elisabet Öberg
- Department of Chemistry - Ångström Laboratories, Molecular Inorganic Chemistry, Uppsala University, Box 523, 75120, Uppsala, Sweden
| | - Sascha Ott
- Department of Chemistry - Ångström Laboratories, Molecular Inorganic Chemistry, Uppsala University, Box 523, 75120, Uppsala, Sweden.
| | - Andreas Orthaber
- Department of Chemistry - Ångström Laboratories, Molecular Inorganic Chemistry, Uppsala University, Box 523, 75120, Uppsala, Sweden.
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28
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Borges A, Solomon GC. An approach to develop chemical intuition for atomistic electron transport calculations using basis set rotations. J Chem Phys 2016; 144:194111. [DOI: 10.1063/1.4950828] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- A. Borges
- Department of Chemistry and Nano-Science Center, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
| | - G. C. Solomon
- Department of Chemistry and Nano-Science Center, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
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29
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Huang GJ, Harris MA, Krzyaniak MD, Margulies EA, Dyar SM, Lindquist RJ, Wu Y, Roznyatovskiy VV, Wu YL, Young RM, Wasielewski MR. Photoinduced Charge and Energy Transfer within meta- and para-Linked Chlorophyll a-Perylene-3,4:9,10-bis(dicarboximide) Donor–Acceptor Dyads. J Phys Chem B 2016; 120:756-65. [DOI: 10.1021/acs.jpcb.5b10806] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Guan-Jhih Huang
- Department of Chemistry and
Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Michelle A. Harris
- Department of Chemistry and
Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Matthew D. Krzyaniak
- Department of Chemistry and
Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Eric A. Margulies
- Department of Chemistry and
Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Scott M. Dyar
- Department of Chemistry and
Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Rebecca J. Lindquist
- Department of Chemistry and
Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Yilei Wu
- Department of Chemistry and
Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Vladimir V. Roznyatovskiy
- Department of Chemistry and
Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Yi-Lin Wu
- Department of Chemistry and
Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Ryan M. Young
- Department of Chemistry and
Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Michael R. Wasielewski
- Department of Chemistry and
Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
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30
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Quan R, Pitler CS, Ratner MA, Reuter MG. Quantitative Interpretations of Break Junction Conductance Histograms in Molecular Electron Transport. ACS NANO 2015; 9:7704-7713. [PMID: 26168212 DOI: 10.1021/acsnano.5b03183] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We develop theoretical and computational tools for extracting quantitative molecular information from experimental conductance histograms for electron transport through single-molecule break junctions. These experimental setups always measure a combination of molecular conductance and direct electrode-electrode tunneling; our derivations explicitly incorporate the effects of such background tunneling. Validation of our models to simulated data shows that background tunneling is crucial for quantitative analyses (even in cases where it appears to be qualitatively negligible), and comparison to experimental data is favorable. Finally, we generalize these ideas to the case of molecules with a destructive interference feature and discuss potential signatures for interference in a conductance histogram.
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31
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Stasiw DE, Zhang J, Wang G, Dangi R, Stein BW, Shultz DA, Kirk ML, Wojtas L, Sommer RD. Determining the Conformational Landscape of σ and π Coupling Using para-Phenylene and “Aviram–Ratner” Bridges. J Am Chem Soc 2015; 137:9222-5. [DOI: 10.1021/jacs.5b04629] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Daniel E. Stasiw
- Department
of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Jinyuan Zhang
- Department
of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Guangbin Wang
- Department
of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Ranjana Dangi
- Department
of Chemistry, The University of New Mexico, MSC03 2060, 1 University of New
Mexico, Albuquerque, New
Mexico 87131-0001, United States
| | - Benjamin W. Stein
- Department
of Chemistry, The University of New Mexico, MSC03 2060, 1 University of New
Mexico, Albuquerque, New
Mexico 87131-0001, United States
| | - David A. Shultz
- Department
of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Martin L. Kirk
- Department
of Chemistry, The University of New Mexico, MSC03 2060, 1 University of New
Mexico, Albuquerque, New
Mexico 87131-0001, United States
| | - Lukasz Wojtas
- Department
of Chemistry, University of South Florida, 4202 East Fowler Avenue, CHE 205, Tampa, Florida 33620-5250, United States
| | - Roger D. Sommer
- Department
of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
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32
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Bergfield JP, Heitzer HM, Van Dyck C, Marks TJ, Ratner MA. Harnessing Quantum Interference in Molecular Dielectric Materials. ACS NANO 2015; 9:6412-6418. [PMID: 26014273 DOI: 10.1021/acsnano.5b02042] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We investigate the relationship between dielectric response and charge transport in molecule-based materials operating in the quantum coherent regime. We find that quantum interference affects these observables differently, for instance, allowing current passing through certain materials to be reduced by orders of magnitude without affecting dielectric behavior (or band gap). As an example, we utilize ab initio electronic structure theory to calculate conductance and dielectric constants of cross-conjugated anthraquinone (AQ)-based and linearly conjugated anthracene (AC)-based materials. In spite of having nearly equal fundamental gaps, electrode bonding configurations, and molecular dimensions, we find a ∼1.7 order of magnitude (∼50-fold) reduction in the conductance of the AQ-based material relative to the AC-based material, a value in close agreement with recent measurements, while the calculated dielectric constants of both materials are nearly identical. From these findings, we propose two molecular materials in which quantum interference is used to reduce leakage currents across a ∼25 Å monolayer gap with dielectric constants larger than 4.5.
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Affiliation(s)
- Justin P Bergfield
- †Department of Chemistry and the Materials Research Center, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Henry M Heitzer
- †Department of Chemistry and the Materials Research Center, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Colin Van Dyck
- †Department of Chemistry and the Materials Research Center, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Tobin J Marks
- †Department of Chemistry and the Materials Research Center, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Mark A Ratner
- †Department of Chemistry and the Materials Research Center, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
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33
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Liu H, He Y, Zhang J, Zhao J, Chen L. A theoretical study of asymmetric electron transport through linearly aromatic molecules. Phys Chem Chem Phys 2015; 17:4558-68. [PMID: 25583004 DOI: 10.1039/c4cp03887h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electron transport through a series of polyacene molecules connected via a π-conjugated bridge (an anthracene molecule) was investigated theoretically by using the nonequilibrium Green's function formalism combined with density functional theory. The results have shown that the asymmetric current-voltage characteristics can be achieved by tuning the position of a side π-bridge linked to the main conjugated backbone. The detailed analyses of the spatial distribution of molecular orbitals as well as the current density interpret how the location of π-bridge strongly affects the intramolecular electronic coupling. The rectification in the molecular junction arises from the localization of the molecular orbitals near the Fermi level and the asymmetric shift of molecule orbital energy levels under positive and negative bias. The rectification ratio decreases with increasing the length of the π-bridge which improves intramolecular electronic coupling between aromatic rings. Furthermore, the rectification properties of conjugated molecules are just slightly affected by the anchoring positions of thiol groups. These results demonstrated that the location and the length of π-bridge, which induce the asymmetric intramolecular coupling, play key roles in the rectification of the linearly aromatic molecules.
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Affiliation(s)
- Hongmei Liu
- Institute of Condensed Matter Physics, Linyi University, Shuangling Road, Linyi 276000, P. R. China
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34
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Abstract
The influence of the competition between polaron formation and population injection on exciton dissociation.
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Affiliation(s)
- Guangqi Li
- Department of Chemistry
- Northwestern University
- Evanston IL
- USA
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35
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Beyond Molecular Conduction: Optical and Thermal Effects in Molecular Junctions. ADVANCES IN CHEMICAL PHYSICS 2014. [DOI: 10.1002/9781118959602.ch12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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36
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Reuter MG, Hansen T. Communication: Finding destructive interference features in molecular transport junctions. J Chem Phys 2014; 141:181103. [DOI: 10.1063/1.4901722] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Matthew G. Reuter
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA
| | - Thorsten Hansen
- Department of Chemistry, H. C. Ørsted Institute, University of Copenhagen, DK 2100 Copenhagen, Denmark
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37
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Parker SM, Smeu M, Franco I, Ratner MA, Seideman T. Molecular junctions: can pulling influence optical controllability? NANO LETTERS 2014; 14:4587-4591. [PMID: 25072807 DOI: 10.1021/nl501629c] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We suggest the combination of single molecule pulling and optical control as a way to enhance control over the electron transport characteristics of a molecular junction. We demonstrate using a model junction consisting of biphenyl-dithiol coupled to gold contacts. The junction is pulled while optically manipulating the dihedral angle between the two rings. Quantum dynamics simulations show that molecular pulling enhances the degree of control over the dihedral angle and hence over the transport properties.
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Affiliation(s)
- Shane M Parker
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
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38
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Maggio E, Troisi A. An expression for the bridge-mediated electron transfer rate in dye-sensitized solar cells. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2014; 372:20130011. [PMID: 24615149 DOI: 10.1098/rsta.2013.0011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We have derived an expression for the rate of electron transfer between a semiconductor and a redox centre connected to the semiconductor via a molecular bridge. This model is particularly useful to study the charge recombination (CR) process in dye-sensitized solar cells, where the dye is often connected to the semiconductor by a conjugated bridge. This formalism, designed to be coupled with density functional theory electronic structure calculations, can be used to explore the effect of changing the bridge on the rate of interfacial electron transfer. As an example, we have evaluated the CR rate for a series of systems that differ in the bridge length.
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Affiliation(s)
- Emanuele Maggio
- Department of Chemistry, and Centre for Scientific Computing, University of Warwick, Coventry CV4 7AL, UK
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39
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Nishizawa S, Hasegawa JY, Matsuda K. Theoretical Investigation of the Dependence of Exchange Interaction on Dihedral Angle between Two Aromatic Rings in a Wire Unit. CHEM LETT 2014. [DOI: 10.1246/cl.131115] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Shohei Nishizawa
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University
| | | | - Kenji Matsuda
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University
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40
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Tsuji Y, Hoffmann R. Frontier Orbital Control of Molecular Conductance and its Switching. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201311134] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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41
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Tsuji Y, Hoffmann R. Frontier Orbital Control of Molecular Conductance and its Switching. Angew Chem Int Ed Engl 2014; 53:4093-7. [DOI: 10.1002/anie.201311134] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Revised: 01/27/2014] [Indexed: 11/11/2022]
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42
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Fowler PW, Pickup BT, Todorova TZ, Borg M, Sciriha I. Omni-conducting and omni-insulating molecules. J Chem Phys 2014; 140:054115. [PMID: 24511930 DOI: 10.1063/1.4863559] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The source and sink potential model is used to predict the existence of omni-conductors (and omni-insulators): molecular conjugated π systems that respectively support ballistic conduction or show insulation at the Fermi level, irrespective of the centres chosen as connections. Distinct, ipso, and strong omni-conductors/omni-insulators show Fermi-level conduction/insulation for all distinct pairs of connections, for all connections via a single centre, and for both, respectively. The class of conduction behaviour depends critically on the number of non-bonding orbitals (NBO) of the molecular system (corresponding to the nullity of the graph). Distinct omni-conductors have at most one NBO; distinct omni-insulators have at least two NBO; strong omni-insulators do not exist for any number of NBO. Distinct omni-conductors with a single NBO are all also strong and correspond exactly to the class of graphs known as nut graphs. Families of conjugated hydrocarbons corresponding to chemical graphs with predicted omni-conducting/insulating behaviour are identified. For example, most fullerenes are predicted to be strong omni-conductors.
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Affiliation(s)
- P W Fowler
- Department of Chemistry, The University of Sheffield, Sheffield S3 7HF, United Kingdom
| | - B T Pickup
- Department of Chemistry, The University of Sheffield, Sheffield S3 7HF, United Kingdom
| | - T Z Todorova
- Department of Chemistry, The University of Sheffield, Sheffield S3 7HF, United Kingdom
| | - Martha Borg
- Department of Chemistry, The University of Sheffield, Sheffield S3 7HF, United Kingdom
| | - Irene Sciriha
- Department of Mathematics, Faculty of Science, University of Malta, Msida MSD 2080, Malta
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43
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Maggio E, Solomon GC, Troisi A. Exploiting quantum interference in dye sensitized solar cells. ACS NANO 2014; 8:409-418. [PMID: 24283471 DOI: 10.1021/nn4045886] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
A strategy to hinder the charge recombination process in dye sensitized solar cells is developed in analogy with similar approaches to modulate charge transport across nanostructures. The system studied is a TiO2 (anatase)-chromophore interface, with an unsaturated carbon bridge connecting the two subunits. A theory for nonadiabatic electron transfer is employed in order to take explicitly into account the contribution from the bridge states mediating the process. If a cross-conjugated fragment is present in the bridge, it is possible to suppress the charge recombination by negative interference of the possible tunnelling path. Calculations carried out on realistic molecules at the DFT level of theory show how the recombination lifetime can be modulated by changes in the electron-withdrawing (donating) character of the groups connected to the cross-conjugated bridge. Tight binding calculations are employed to support the interpretation of the atomistic simulations.
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Affiliation(s)
- Emanuele Maggio
- Chemistry Department & Centre of Scientific Computing, University of Warwick , Coventry CV4 7AL, United Kingdom
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44
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45
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Emanuelsson R, Wallner A, Ng EAM, Smith JR, Nauroozi D, Ott S, Ottosson H. Cross-hyperconjugation: an unexplored orbital interaction between π-conjugated and saturated molecular segments. Angew Chem Int Ed Engl 2012. [PMID: 23184861 DOI: 10.1002/anie.201206030] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Rikard Emanuelsson
- Department of Chemistry-BMC, Uppsala University, Box 576, 75123 Uppsala, Sweden
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46
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Emanuelsson R, Wallner A, Ng EAM, Smith JR, Nauroozi D, Ott S, Ottosson H. Cross-Hyperconjugation: An Unexplored Orbital Interaction between π-Conjugated and Saturated Molecular Segments. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201206030] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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47
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48
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Li G, Nitzan A, Ratner MA. Yield of exciton dissociation in a donor–acceptor photovoltaic junction. Phys Chem Chem Phys 2012; 14:14270-6. [DOI: 10.1039/c2cp41532a] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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49
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Galperin M, Nitzan A. Molecular optoelectronics: the interaction of molecular conduction junctions with light. Phys Chem Chem Phys 2012; 14:9421-38. [PMID: 22648067 DOI: 10.1039/c2cp40636e] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Michael Galperin
- Department of Chemistry and Biochemistry, University of California at San Diego, La Jolla, CA 92093, USA
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50
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Solomon GC, Bergfield JP, Stafford CA, Ratner MA. When "small" terms matter: Coupled interference features in the transport properties of cross-conjugated molecules. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2011; 2:862-71. [PMID: 22259770 PMCID: PMC3257512 DOI: 10.3762/bjnano.2.95] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 11/25/2011] [Indexed: 05/23/2023]
Abstract
Quantum interference effects offer opportunities to tune the electronic and thermoelectric response of a quantum-scale device over orders of magnitude. Here we focus on single-molecule devices, in which interference features may be strongly affected by both chemical and electronic modifications to the system. Although not always desirable, such a susceptibility offers insight into the importance of "small" terms, such as through-space coupling and many-body charge-charge correlations. Here we investigate the effect of these small terms using different Hamiltonian models with Hückel, gDFTB and many-body theory to calculate the transport through several single-molecule junctions, finding that terms that are generally thought to only slightly perturb the transport instead produce significant qualitative changes in the transport properties. In particular, we show that coupling of multiple interference features in cross-conjugated molecules by through-space coupling will lead to splitting of the features, as can correlation effects. The degeneracy of multiple interference features in cross-conjugated molecules appears to be significantly more sensitive to perturbations than those observed in equivalent cyclic systems and this needs to be considered if such supernodes are required for molecular thermoelectric devices.
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Affiliation(s)
- Gemma C Solomon
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
| | - Justin P Bergfield
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
| | - Charles A Stafford
- Department of Physics, University of Arizona, 1118 East Fourth Street, Tucson, AZ 85721, USA
| | - Mark A Ratner
- Department of Chemistry, Northwestern University, 2145 Sheridan Rd, Evanston, IL 60208, USA
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