Combined Effect of Polar Substituents on the Electronic Flows in the Carotenoid Molecular Wires

Zhao, Yanan; Lindsay, Stuart; Jeon, Sunhwa; Kim, Hyung Jun; Su, Liang; Lim, Boram; Koo, Sangho

doi:10.1002/chem.201300984

Cited by 17 publications

(16 citation statements)

References 39 publications

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“…The electronic structures and transport properties of organic materials are frequently modified and tuned by means of attaching functional groups . Here, the influence of functional groups is exemplarily studied using benzenes connected to electric leads at the para position.…”

Section: Resultsmentioning

confidence: 99%

Current density analysis of electron transport through molecular wires in open quantum systems

Nozaki

Schmidt

2017

J Comput Chem

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The current density in molecular wires connected to contacts is investigated within the nonequilibrium Green's function formalism combined with the Landauer approach. Energy-dependent and total current density through a series of molecular junctions are calculated in real space representation. A rich variety of current patterns including pronounced ring currents ("vortices") are found even in the defect-free minimal building blocks of molecular devices. The influences of contact positions, functional groups as well as atomic defects on the transport properties are examined systematically for prototypical ortho-, meta-, and para-substituted benzenes as well as heteroaromatic systems. It is found that substitutional functional groups mainly shift the molecular levels and retain characteristic transport channels, while a significant change of electronic pathways and conductance is induced by hetero-aromaticity. The current distribution is used to calculate the static magnetic field distribution in the carbon-based conductors. © 2017 Wiley Periodicals, Inc.

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Section: Resultsmentioning

confidence: 99%

Current density analysis of electron transport through molecular wires in open quantum systems

Nozaki

Schmidt

2017

J Comput Chem

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“…Factors such as the length, conjugation, conformation, or even changes in the planarity of the molecule, and anchoring groups of the molecule under study, are crucial for achieving reliable electronic devices with desirable performance . In particular, several studies have been centered on understanding the effect that different anchoring groups can have on the conductance in a single‐molecule device, anchoring groups such as HS,– COOH,, NH 2 ,, MeS,, Me 2 P, MeSe, thiophene, selenophene, tripodal anchors with pyridine rings, pyridine,, CN,, benzo‐hydrothiophene,, SO 3 − , OH, alkyne,, NO 2 ,, and benzothiophene ,. Thus, establishing a relationship between the intrinsic molecular properties and device performance is a central task for developing reliable molecular electronic devices.…”

Section: Introductionmentioning

confidence: 99%

Multiscale Approach to the Study of the Electronic Properties of Two Thiophene Curcuminoid Molecules

Etcheverry-Berríos

Olavarría

Perrin

et al. 2016

Chemistry A European J

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We studied the electronic and conductance properties of two thiophene-curcuminoid molecules, 2-thphCCM (1) and 3-thphCCM (2), where the only structural difference is the position of the sulfur atoms in the thiophene terminal groups. We used electrochemical techniques as well as UV-vis absorption studies to obtain the values of the HOMO-LUMO band gap energies, showing that molecule 1 has lower values than 2. Theoretical calculations show the same trend. Self-assembled monolayers (SAMs) of these molecules were studied using electrochemistry, showing that the interaction with gold reduces drastically the HOMO-LUMO gap in both molecules to almost the same value. Single-molecule conductance measurements show that molecule 2 has two different conductance values, whereas molecule 1 exhibits only one. Based on theoretical calculations we conclude that the lowest conductance value, similar in both molecules, corresponds to a van der waals interaction between the thiophene ring and the electrodes. The one order of magnitud higher conductance value for molecule 2 corresponds to a covalent interaction between the sulfur atoms and the gold electrodes.

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“…[25,26] Here we report the chemical synthesis ands ingle-molecule conductivity measurements of an ew series of carotenoid molecular wires whose conductivity can be fine-tuned by inserting multiple phenyls ubstituents and by controlling both their chemicalc omposition and conformation.T his multiple control of the phenyl substituents imbedded in the carotenoid backbone allows for fine-tuning of the single-molecule wire conductance over an order of magnitude, and establishes an ovel methodological platform to achieve ad esired conductance output in an anoscale molecular circuit. [1,2,6,20,28] The second finding from the single-molecule conductance measurements is the amplified evolution of the conductance with the electron-donating character of the substituents in the N-series.W hen comparing both C-and N-series,t he insertion of PhÀCl substituents led to an indistinguishable conductivity in both series (initial data point in Figure 4);t his resulti mplies that the insertiono ft he nitrogen atom in the N-series is not directly involved in the electron transport through the carotenoid backbone. The ÀSCH 3 as anchoring groups allow for the formation of robusts ingle-molecule junctions with limited variation of the contact configuration and narrow conductance distributions.…”

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confidence: 99%

Fine‐Tuning of Single‐Molecule Conductance by Tweaking Both Electronic Structure and Conformation of Side Substituents

Aragonès

Darwish

et al. 2015

Chemistry A European J

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Herein, we describe a method to fine-tune the conductivity of single-molecule wires by employing a combination of chemical composition and geometrical modifications of multiple phenyl side groups as conductance modulators embedded along the main axis of the electronic pathway. We have measured the single-molecule conductivity of a novel series of phenyl-substituted carotenoid wires whose conductivity can be tuned with high precision over an order of magnitude range by modulating both the electron-donating character of the phenyl substituent and its dihedral angle. It is demonstrated that the electronic communication between the phenyl side groups and the molecular wire is maximized when the phenyl groups are twisted closer to the plane of the conjugated molecular wire. These findings can be refined to a general technique for precisely tuning the conductivity of molecular wires.

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Combined Effect of Polar Substituents on the Electronic Flows in the Carotenoid Molecular Wires

Cited by 17 publications

References 39 publications

Current density analysis of electron transport through molecular wires in open quantum systems

Current density analysis of electron transport through molecular wires in open quantum systems

Multiscale Approach to the Study of the Electronic Properties of Two Thiophene Curcuminoid Molecules

Fine‐Tuning of Single‐Molecule Conductance by Tweaking Both Electronic Structure and Conformation of Side Substituents

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