Charge Transfer through Redox Molecular Junctions in Nonequilibrated Solvents

Henning Kirchberg, Michael Thorwart, Abraham Nitzan

Research output: Contribution to journalArticlepeer-review

Abstract

Molecular conduction operating in dielectric solvent environments is often described using kinetic rates based on the Marcus theory of electron transfer at a molecule-metal electrode interface. However, the successive nature of charge transfer in such a system implies that the solvent does not necessarily reach equilibrium in such processes. Here we generalize the theory to account for solvent nonequilibrium and consider a molecular junction consisting of an electronic donor-acceptor system coupled to two metallic electrodes and placed in a polarizable solvent. We determine the nonequilbrium distribution of the solvent by solving diffusion equations in the strong- and weak-friction limits and calculate the charge current and its fluctuating behavior. In extreme limits, the absence of the solvent or fast solvent relaxation, the charge-transfer statistics is Poissonian, while it becomes correlated by the dynamic solvent between these limits. A Kramers-like turnover of the nonequilibrium current as a function of the solvent damping is found. Finally, we propose a way to tune the solvent-induced damping using geometrical control of the solvent dielectric response in nanostructured solvent channels.

Original languageEnglish
Pages (from-to)1729-1737
Number of pages9
JournalJournal of Physical Chemistry Letters
Volume11
Issue number5
DOIs
StatePublished - 5 Mar 2020
Externally publishedYes

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