Electrical Conductance of Conjugated Oligomers at the Single Molecule Level

Huber, R.; González, M. Teresa; Wu, Songmei; Langer, Michael; Grunder, Sergio; Horhoiu, Viviana; Mayor, Marcel; Bryce, Martin R.; Wang, Changsheng; Jitchati, Rukkiat; Schönenberger, Christian; Calame, Michel

doi:10.1021/ja0767940

Cited by 184 publications

(214 citation statements)

References 40 publications

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“…Measurements of the conductance through oligophenylenes and carotanoids of different length also showed exponential dependence on molecule length, but with a smaller decay constant as expected [23,24]. Comparison of the conductance through alkanes to that through prototypical molecular wires with extended pi electron states (oligophenyleneethynylene, OPV and oligophenylenevinylene, OPV) showed substantially higher conductance through the conjugated molecules and a rational dependence on the HOMO-LUMO gap [23,[25][26][27]. In a series of asymmetric junctions formed with oligophenyl and acene monothiols, systematic changes in conductance with electrode Fermi level alignment were observed [28].…”

Section: Introductionmentioning

confidence: 69%

Amine-linked single-molecule circuits: systematic trends across molecular families

Hybertsen¹,

Venkataraman²,

Klare³

et al. 2008

J. Phys.: Condens. Matter

148

198

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Abstract.A comprehensive review is presented of single molecule junction conductance measurements across families of molecules measured while breaking a gold point contact in a solution of molecules with amine end groups. A theoretical framework unifies the picture for the amine-gold link bonding and the tunnel coupling through the junction using Density Functional Theory based calculations. The reproducible electrical characteristics and utility for many molecules is shown to result from the selective binding between the gold electrodes and amine link groups through a donor-acceptor bond to undercoordinated gold atoms. While the bond energy is modest, the maximum force sustained by the junction is comparable to, but less than, that required to break gold point contacts. The calculated tunnel coupling provides conductance trends for all 41 molecule measurements presented here, as well as insight into the variability of conductance due to the conformational changes within molecules with torsional degrees of freedom. The calculated trends agree to within a factor of two of the measured values for conductance ranging from 10 -7 G 0 to 10 -2 G 0 , where G 0 is the quantum of conductance (2e 2 /h).

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Section: Introductionmentioning

confidence: 69%

Amine-linked single-molecule circuits: systematic trends across molecular families

Hybertsen¹,

Venkataraman²,

Klare³

et al. 2008

J. Phys.: Condens. Matter

148

198

View full text Add to dashboard Cite

show abstract

“…Previous studies showed that acetyl protected sulfur are suitable protecting group for immobilization on gold. [217] [218] Recently, it has been shown that a properly designed azobenzene molecule can undergo cis trans photoisomerization in large domains at surfaces. This switch, which occurs in densely packed single component SAMs without perturbing the molecular lattice, is complete over hundreds of molecules, and it exhibits a cooperative character.…”

Section: Design Of Sulfur Functionalized Azo Macrocyclesmentioning

confidence: 99%

Shape‐Switchable Azo‐Macrocycles

et al. 2009

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The synthesis of four shape‐switchable macrocycles comprising different peripheral substituents is described. The macrocycles 1–4 consist of m‐terphenyl semicircles interlinked by two azo joints. These macrocycles were assembled from nitro‐functionalized m‐terphenyl moieties through reductive dimerization. The semicircles were assembled through Suzuki cross‐coupling reactions. The molecular weights of the macrocycles were determined by vapour pressure osmometry, because mass spectrometry failed in the cases of 2 and 3. The E → Z photoisomerization reactions were analysed by UV/Vis spectroscopy complemented by 1H NMR studies. A very slow thermal back‐reaction indicated considerable stabilization of the Z isomer. The reduced efficiency of the thermal back‐reaction probably arises from the reduced degree of freedom due to the mechanical interlinking of the two azo groups. The photostationary state consisted of all‐Z (85 %) and all‐E isomers (15 %). The E → Z transformation induced by irradiation displayed simple exponential kinetics, which indicates pairwise switching of the two azo groups in a macrocycle, at least on the timescale under investigation. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

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“…12,13 In particular OPE3 systems (3 refers to the number of phenyl rings in the backbone) have been widely studied in metal−single-molecule−metal 2 junctions. [14][15][16][17][18][19][20][21] For the purpose of designing future single-molecule devices, it is interesting to develop strategies for independently tuning electrical, mechanical and packing properties. In the present work, we demonstrate that this can be achieved by systematically varying the substituents on the central ring of gold-OPE3-gold junctions.…”

Section: Introductionmentioning

confidence: 99%

Structural versus Electrical Functionalization of Oligo(phenylene ethynylene) Diamine Molecular Junctions

et al. 2014

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We explore both experimentally and theoretically the conductance and packing of molecular junctions based on oligo(phenyleneethynylene) (OPE) diamine wires, when a series of functional groups are incorporated into the wires. Using the scanning tunnelling microscopy breakjunction (STM BJ) technique, we study these compounds in two environments (air and 1,2,4-trichlorobenzene) and explore different starting molecular concentrations. We show that the electrical conductance of the molecular junctions exhibits variations among different compounds, which are significant at standard concentrations but become unimportant when working at a low enough concentration. This shows that the main effect of the functional groups is to affect the packing of the molecular wires, rather than to modify their electrical properties. Our theoretical calculations consistently predict no significant changes in the conductance of the wires due to the electronic structure of the functional groups, although their ability to hinder ring rotations within the OPE backbone can lead to higher conductances at higher packing densities.

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Electrical Conductance of Conjugated Oligomers at the Single Molecule Level

Cited by 184 publications

References 40 publications

Amine-linked single-molecule circuits: systematic trends across molecular families

Amine-linked single-molecule circuits: systematic trends across molecular families

Shape‐Switchable Azo‐Macrocycles

Structural versus Electrical Functionalization of Oligo(phenylene ethynylene) Diamine Molecular Junctions

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