Impact of derivatization on electron transmission through dithienylethene-based photoswitches in molecular junctions

Dyck, Colin Van; Geskin, Victor; Kronemeijer, Auke Jisk; Leeuw, Dago M. de; Cornil, Jérôme

doi:10.1039/c3cp44132f

Cited by 52 publications

(86 citation statements)

References 60 publications

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“…In this context, we have recently investigated at a theoretical level photoswitching single molecular junctions based on a diarylethene photochromic core, see chemical structure in Figure ; the choice of this switching unit was initially motivated by its frequent use in corresponding experimental studies . This molecule exhibits a fully conjugated isomer (closed form, see Figure ) which can be reversibly photoswitched to a less conjugated twisted isomer (open form, see Figure ), with a concomitant increase by about two orders of magnitude of the molecular resistance.…”

Section: Introductionmentioning

confidence: 58%

Fermi Level Pinning and Orbital Polarization Effects in Molecular Junctions: The Role of Metal Induced Gap States

Dyck

Geskin

Cornil

2014

Adv Funct Materials

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Understanding the alignment of molecular orbitals and corresponding transmission peaks with respect to the Fermi level of the electrodes is a major challenge in the fi eld of molecular electronics. In order to design functional devices, it is of utmost importance to assess whether controlled changes in the electronic structure of isolated compounds are preserved once they are inserted in the molecular junctions. Here, light is shed on this central issue by performing density functional theory calculations on junctions including diarylethene-based molecules. It is demonstrated that the chemical potential equalization principle allows to rationalize the existence or not of a Fermi level pinning (i.e., same alignment in spite of a varying ionization potential in the isolated compounds), pointing to the essential role played by metal induced gap states (MIGS). It is further evidenced that the degree of level pinning is intimately linked to the degree of orbital polarization when a bias is applied between the two electrodes.

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Section: Introductionmentioning

confidence: 58%

Fermi Level Pinning and Orbital Polarization Effects in Molecular Junctions: The Role of Metal Induced Gap States

Dyck

Geskin

Cornil

2014

Adv Funct Materials

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“…Conventional density functional theory (DFT) calculations, which represent the vast majority of the theoretical studies on molecular transport, 19,[22][23][24][25][26][27][28][29][30][31][32][33] are able to provide important information, e.g. on molecular conformation and contact topology.…”

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confidence: 99%

Experimental and Theoretical Analysis of Nanotransport in Oligophenylene Dithiol Junctions as a Function of Molecular Length and Contact Work Function

et al. 2015

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We report the results of an extensive investigation of metal-molecule-metal tunnel junctions based on oligophenylene dithiols (OPDs) bound to several types of electrodes (M1-S-(C6H4)n-S-M2, with 1 ≤ n ≤ 4 and M1,2 = Ag, Au, Pt) to examine the impact of molecular length (n) and metal work function (Φ) on junction properties. Our investigation includes (1) measurements by scanning Kelvin probe microscopy of electrode work function changes (ΔΦ = ΦSAM - Φ) caused by chemisorption of OPD self-assembled monolayers (SAMs), (2) measurements of junction current-voltage (I-V) characteristics by conducting probe atomic force microscopy in the linear and nonlinear bias ranges, and (3) direct quantitative analysis of the full I-V curves. Further, we employ transition voltage spectroscopy (TVS) to estimate the energetic alignment εh = EF - EHOMO of the dominant molecular orbital (HOMO) relative to the Fermi energy EF of the junction. Where photoelectron spectroscopy data are available, the εh values agree very well with those determined by TVS. Using a single-level model, which we justify via ab initio quantum chemical calculations at post-density functional theory level and additional UV-visible absorption measurements, we are able to quantitatively reproduce the I-V measurements in the whole bias range investigated (∼1.0-1.5 V) and to understand the behavior of εh and Γ (contact coupling strength) extracted from experiment. We find that Fermi level pinning induced by the strong dipole of the metal-S bond causes a significant shift of the HOMO energy of an adsorbed molecule, resulting in εh exhibiting a weak dependence with the work function Φ. Both of these parameters play a key role in determining the tunneling attenuation factor (β) and junction resistance (R). Correlation among Φ, ΔΦ, R, transition voltage (Vt), and εh and accurate simulation provide a remarkably complete picture of tunneling transport in these prototypical molecular junctions.

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“…18 Diarylethylene based switches, for example, do not only change their total transmission but also the position of the resonances. 19 Our predictions could be examined on nanoparticle arrays interlinked by molecular bridges, but this would also require our model to include percolation effects. 18 A more direct evaluation can be done on nanogap devices with a single nanoparticle placed in between the electrodes using dielectrophoresis.…”

Section: Approach 1: Lorentzian Transmissionmentioning

confidence: 99%

Inelastic cotunneling with energy-dependent contact transmission

Blok

Mojarro

Maduro

et al. 2017

The Journal of Chemical Physics

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Destructive quantum interference in electron transport: A reconciliation of the molecular orbital and the atomic orbital perspective The Journal of Chemical Physics 146, 092308092308 (2016) We investigate inelastic cotunneling in a model system where the charging island is connected to the leads through molecules with energy-dependent transmission functions. To study this problem, we propose two different approaches. The first is a pragmatic approach that assumes Lorentzian-like transmission functions that determine the transmission probability to the island. Using this model, we calculate current versus voltage (IV) curves for increasing resonance level positions of the molecule. We find that shifting the resonance energy of the molecule away from the Fermi energy of the contacts leads to a decreased current at low bias, but as bias increases, this difference decreases and eventually inverses. This is markedly different from IV behavior outside the cotunneling regime. The second approach involves multiple cotunneling where also the molecules are considered to be in the Coulomb blockade regime. We find here that when E c eV, k B T , the IV behavior approaches the original cotunneling behavior proposed by Averin and Nazarov [Phys. Rev. Lett. 65, 2446-2449 (1990)]. Published by AIP Publishing. [http://dx

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Impact of derivatization on electron transmission through dithienylethene-based photoswitches in molecular junctions

Abstract: Impact of derivatization on electron transmission through dithienylethene-based photoswitches in molecular junctions Van Dyck, Colin; Geskin, Victor; Kronemeijer, Auke J.; de Leeuw, Dago M.; Cornil, Jerome; Cornil, Jérôme

Cited by 52 publications

References 60 publications

Fermi Level Pinning and Orbital Polarization Effects in Molecular Junctions: The Role of Metal Induced Gap States

Fermi Level Pinning and Orbital Polarization Effects in Molecular Junctions: The Role of Metal Induced Gap States

Experimental and Theoretical Analysis of Nanotransport in Oligophenylene Dithiol Junctions as a Function of Molecular Length and Contact Work Function

Inelastic cotunneling with energy-dependent contact transmission

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