Exciton- and Light-induced Current in Molecular Nanojunctions

TL;DR

This paper investigates how exciton and light interactions influence current flow in molecular nanojunctions, revealing that exciton coupling can significantly alter conduction and proposing optical methods to enhance charge transfer.

Contribution

It introduces a model showing exciton coupling's impact on current and proposes a chirped pulse technique for improved charge transfer in molecular junctions.

Findings

Exciton coupling can significantly affect source-drain current.

Electron-hole excitations can dominate conduction under certain conditions.

Chirped pulses can enhance charge transfer in unbiased junctions.

Abstract

We consider exciton- and light-induced current in molecular nanojunctions. Using a model comprising a two two-level sites bridge connecting free electron reservoirs we show that the exciton coupling between the sites of the molecular bridge can markedly effect the source-drain current through a molecular junction. In some cases when excited and unexcited states of the sites are coupled differently to the leads, the contribution from electron-hole excitations can exceed the Landauer elastic current and dominate the observed conduction. We have proposed an optical control method using chirped pulses for enhancing charge transfer in unbiased junctions where the bridging molecule is characterized by a strong charge-transfer transition.