Adsorption-Induced Solvent-Based Electrostatic Gating of Charge Transport through Molecular Junctions

TL;DR

This paper demonstrates how solvent molecules can reversibly modulate charge transport in molecular junctions by shifting electrostatic potentials, supported by first-principles calculations and experiments.

Contribution

It introduces a combined theoretical and experimental approach to explain solvent-induced conductance changes via electrostatic effects in molecular junctions.

Findings

Solvent molecules can alter conductance by over 50%.

Electrostatic model accurately predicts conductance changes.

Solvent effects offer a new method for controlling molecular-scale transport.

Abstract

Recent experiments have shown that transport properties of molecular-scale devices can be reversibly altered by the surrounding solvent. Here, we use a combination of first-principles calculations and experiment to explain this change in transport properties through a shift in the local electrostatic potential at the junction caused by nearby conducting and solvent molecules chemically bound to the electrodes. This effect is found to alter the conductance of bipyridine - gold junctions by more than 50%. Moreover, we develop a general electrostatic model that quantitatively predicts the relationship between conductance and the binding energies and dipoles of the solvent and conducting molecules. Our work shows that solvent induced effects are a viable route for controlling charge and energy transport at molecular-scale interfaces.