Electron Transfer rate between a electrode and a bridged redox

TL;DR

This paper derives a bias-dependent expression for electron transfer rates from a solvated redox to an electrode via a bridge, considering resonance tunneling and solvation effects, with implications for controlling electron flow.

Contribution

It provides an explicit analytical formula for electron transfer rates through a bridged molecule, incorporating bias, bridge length, and interaction effects, which was not previously available.

Findings

Electron transfer can be blocked at certain voltages with specific coupling values.

Resonance tunneling significantly influences transfer rates.

The model applies to bridges of arbitrary length, demonstrated with a 5-atom example.

Abstract

We derive an explict bias dependent expression for electron transfer reaction rate from a solvated redox to a electrode through a bridged molecule of arbitrary length. The interaction of the solvated redox with the solvent is modelled as a classical harmonic oscillator bath. The effect of competing process, namely resonance tunneling between redox and bridge and the solvation of the redox is investigated. Plots were produced for the case of 5 atom bridge. Our analysis shows that for certain suitable value of nearest-neighbour coupling, it is possible to block electron transfer in certain intermediate voltage regime