Manipulating Quantum Interference between σ and π Orbitals in Single-Molecule Junctions via Chemical Substitution and Environmental Control

Skipper, Hannah E.; Lawson, Brent; Pan, Xiaoyun; Degtiareva, Vera; Kamenetska, Maria

doi:10.1021/acsnano.3c04963

Cited by 4 publications

(2 citation statements)

References 56 publications

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“…These curves possess sharp dips near E = 0, signaling the presence of DQI. [38][39][40][41][42][43][44] For electrodes connected to sites 1 and 4 the purple-sold curve is produced and exhibits CQI, whereas for electrodes connected to sites 2 and 3, the light green-sold curve is produced, which possesses a DQI dip. These results for a tight binding model with a single bond H ij forming the bridge between the monomers, which is the simplest model of 1, in which an alkane chain bridges the dimer.…”

Section: Methodsmentioning

confidence: 99%

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Tuning quantum interference through molecular junctions formed from cross-linked OPE-3 dimers

Alanazi,

Alajmi,

Aljobory

et al. 2024

J. Mater. Chem. C

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Section: Methodsmentioning

confidence: 99%

“…In the literature, and as discussed in a recent textbook, 8 there are many demonstrations of quantum interference effects in monomer molecules, starting with the first demonstration DQI 42 in 2011 and including more recent demonstrations of QI, such as ref. 43–45 switching in ref. 46–49 and QI in graphene junctions.…”

Section: Methodsmentioning

confidence: 99%

Tuning quantum interference through molecular junctions formed from cross-linked OPE-3 dimers

Alanazi,

Alajmi,

Aljobory

et al. 2024

J. Mater. Chem. C

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Azaindole: A Candidate Anchor for Regulating Charge Polarity and Inducing Resonance Transmission at the Fermi Level via Dehydrogenation

Wang,

Zhou,

et al. 2024

J. Phys. Chem. A

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Tuning the polarity of charge carriers is essential for designing molecular logic devices in molecular electronics. In this study, the electrical transport properties of a family of azaindole-anchored single-molecule junctions have been investigated using density functional theory combined with the nonequilibrium Green's function method. The obtained results reveal that dehydrogenation is an effective method for reversing the polarity of charge carriers. The molecular junctions based on the entire azaindole unit are n-type and contain electrons as the principal charge carriers, whereas the dehydrogenated junctions are p-type and contain holes as the main carriers. Furthermore, the azaindole anchors undergo a transition from an electron-rich to an electron-deficient state due to dehydrogenation, which is the original cause of the charge carrier polarity conversion. Dehydrogenated molecular junctions also exhibit the Fermi pinning effect and a sharp highest occupied molecular orbital (HOMO) resonance peak at the Fermi level. In addition, using Pt electrodes instead of Au electrodes is a means of producing a HOMO resonance peak a for azaindole-based molecular junctions. This work demonstrates the enormous potential of utilizing azaindole-anchored molecular junctions for the implementation of molecular logic and multifunctional molecular devices.

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Extreme Anomalous Conductance Enhancement in Neutral Diradical Acene-like Molecular Junctions

Lawson,

Vidal,

Luna

et al. 2024

ACS Nano

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We achieve, at room temperature, conductance enhancements over 2 orders of magnitude in single molecule circuits formed with polycyclic benzoquinoidal (BQ n ) diradicals upon increasing molecular length by ∼5 Å. We find that this extreme and atypical anti-ohmic conductance enhancement at longer molecular lengths is due to the diradical character of the molecules, which can be described as a topologically nontrivial electronic state, and results in constructive interference between the frontier molecular orbitals. The distinct feature of the compounds studied here as molecular wires is that they are characterized by moderate diradical character in the neutral state, allowing for robust and facile measurements of their transport properties. We adapt the 1D-SSH model, originally developed to examine electronic topological order in linear carbon chains, to the polycyclic systems studied here and find that it captures the anti-ohmic trends in this molecular series. Specifically, our model reveals that the mechanism of conductance enhancement with length in polycyclic systems is constructive quantum interference between the frontier orbitals with nontrivial topology, which is present in acene-like, but not in linear, molecular systems. Importantly, we use our model to predict and experimentally validate that anti-ohmic trends can be engineered through synthetic adjustments of the diradical character of the acene-like molecules. Overall, we achieve extreme anti-ohmic enhancement and mechanistic insight into electronic transport in a class of materials that we identify here as promising candidates for creating highly conductive and tunable nanoscale wires.

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Manipulating Quantum Interference between σ and π Orbitals in Single-Molecule Junctions via Chemical Substitution and Environmental Control

Cited by 4 publications

References 56 publications

Tuning quantum interference through molecular junctions formed from cross-linked OPE-3 dimers

Tuning quantum interference through molecular junctions formed from cross-linked OPE-3 dimers

Azaindole: A Candidate Anchor for Regulating Charge Polarity and Inducing Resonance Transmission at the Fermi Level via Dehydrogenation

Extreme Anomalous Conductance Enhancement in Neutral Diradical Acene-like Molecular Junctions

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