Structural aspects of redox-mediated electron tunneling

Rudnev, Alexander V.; Pobelov, Ilya V.; Wandlowski, Thomas

doi:10.1016/j.jelechem.2010.11.014

Cited by 18 publications

(19 citation statements)

References 58 publications

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“…2C). This sigmoidal dependence differs from that in most previous work, which reported a peak in the conductance vs. potential plot according with incoherent two-step sequential hopping (22,25,(30)(31)(32), coherent one-step tunneling (33)(34)(35)(36)(37), or a fast coherent/incoherent channel coupled with a low hopping-rate redox channel (38)(39)(40). The former rests on the assumption that an electron (or a hole) hops from one electrode to the molecule first and then out of the molecule to the second electrode after losing its phase coherence (i.e., full vibrational relaxation of the molecule in the intermediate electronic state).…”

Section: Significancecontrasting

confidence: 99%

Transition from stochastic events to deterministic ensemble average in electron transfer reactions revealed by single-molecule conductance measurement

Wang

et al. 2019

Proc. Natl. Acad. Sci. U.S.A.

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Electron transfer reactions can now be followed at the single-molecule level, but the connection between the microscopic and macroscopic data remains to be understood. By monitoring the conductance of a single molecule, we show that the individual electron transfer reaction events are stochastic and manifested as large conductance fluctuations. The fluctuation probability follows first-order kinetics with potential dependent rate constants described by the Butler–Volmer relation. Ensemble averaging of many individual reaction events leads to a deterministic dependence of the conductance on the external electrochemical potential that follows the Nernst equation. This study discloses a systematic transition from stochastic kinetics of individual reaction events to deterministic thermodynamics of ensemble averages and provides insights into electron transfer processes of small systems, consisting of a single molecule or a small number of molecules.

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Section: Significancecontrasting

confidence: 99%

Transition from stochastic events to deterministic ensemble average in electron transfer reactions revealed by single-molecule conductance measurement

Wang

et al. 2019

Proc. Natl. Acad. Sci. U.S.A.

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“…/HOPG can be explained by redox‐mediated electron tunneling (RMET) through surface‐confined redox‐active molecules . RMET was experimentally observed by STM (and/or tunneling spectroscopy), for example, for the adlayers on gold terminated by redox‐active moieties, such as viologens, ferrocene, and transition‐metal complexes –. Thus, the in situ STM measurements confirm the strong binding of redox‐active PTM radicals to HOPG step edges.…”

Section: Resultsmentioning

confidence: 76%

Covalent Modification of Highly Ordered Pyrolytic Graphite with a Stable Organic Free Radical by Using Diazonium Chemistry

Seber

Rudnev

Droghetti

et al. 2016

Chemistry A European J

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A novel, persistent, electrochemically active perchlorinated triphenylmethyl (PTM) radical with a diazonium functionality has been covalently attached to highly ordered pyrolytic graphite (HOPG) by electrografting in a single-step process. Electrochemical scanning tunneling microscopy (EC-STM) and Raman spectroscopy measurements revealed that PTM molecules had a higher tendency to covalently react at the HOPG step edges. The cross-section profiles from EC-STM images showed that there was current enhancement at the functionalized areas, which could be explained by redox-mediated electron tunneling through surface-confined redox-active molecules. Cyclic voltammetry clearly demonstrated that the intrinsic properties of the organic radical were preserved upon grafting and DFT calculations also revealed that the magnetic character of the PTM radical was preserved.

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“…A redox-assisted enhancement of the tunnelling current was reported before for a variety of molecules bound to metal electrodes. [10][11][12] However, the present study represents the first report on a redox-molecule enhanced response in a nanoscale tunnelling junction as formed between a metal (gold) STM tip and a silicon substrate modified with a covalently attached functional molecule at an electrochemical solid/liquid interface. We notice that the enhancement of the tunnelling current in metal|molecule|metal tunnelling junctions is observed when both substrate and tip potentials approach the potential of the redox process under study.…”

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confidence: 82%

Electrochemical scanning tunnelling spectroscopy of a ferrocene-modified n-Si(111)-surface: electrolyte gating and ambipolar FET behaviour

et al. 2011

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Structural aspects of redox-mediated electron tunneling

Cited by 18 publications

References 58 publications

Transition from stochastic events to deterministic ensemble average in electron transfer reactions revealed by single-molecule conductance measurement

Transition from stochastic events to deterministic ensemble average in electron transfer reactions revealed by single-molecule conductance measurement

Covalent Modification of Highly Ordered Pyrolytic Graphite with a Stable Organic Free Radical by Using Diazonium Chemistry

Electrochemical scanning tunnelling spectroscopy of a ferrocene-modified n-Si(111)-surface: electrolyte gating and ambipolar FET behaviour

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