Transient Dynamics in Molecular Junctions: Coherent Bichromophoric Molecular Electron Pumps

TL;DR

This paper explores how quantum coherences in single-molecule junctions can be harnessed to create electron pumps, demonstrating transient excitation can induce charge transfer without bias, with potential applications in energy conversion.

Contribution

It introduces a novel mechanism utilizing intra-molecular quantum coherences for electron pumping in bi-chromophoric molecular junctions, highlighting transient excitation effects.

Findings

Transient excitation induces charge transfer without bias.

Quantum coherence enables selective electron pumping.

Potential application in energy conversion and storage.

Abstract

The possibility of using single molecule junctions as electron pumps for energy conversion and storage is considered. It is argued that the small dimensions of these systems enable to make use of unique intra-molecular quantum coherences in order to pump electrons between two leads and to overcome relaxation processes which tend to suppress the pumping efficiency. In particular, we demonstrate that a selective transient excitation of one chromophore in a bi-chromophoric donor-bridge-acceptor molecular junction model yields currents which transfer charge (electron and holes) unevenly to the two leads in the absence of a bias potential. The utility of this mechanism for charge pumping in steady state conditions is proposed.