Controlling the conductance of molecular junctions using proton transfer reactions: A theoretical model study

TL;DR

This study presents a theoretical model demonstrating how intramolecular proton transfer reactions can be used to control the conductance of molecular junctions, enabling potential applications as molecular transistors or diodes.

Contribution

A generic quantum model showing how proton localization influences conductance, controlled by external electric fields, with analysis across different hydrogen bond regimes.

Findings

Proton transfer can switch junctions between high and low conductance states.

Weak hydrogen bonds with significant energy barriers enable transistor-like behavior.

Control of conductance depends on proton localization and external electric fields.

Abstract

The influence of an intramolecular proton transfer reaction on the conductance of a molecular junction is investigated employing a generic model, which includes the effects of the electric field of the gate and leads electrodes and the coupling to a dissipative environment. Using a quantum master equation approach it is shown that, depending on the localization of the proton, the junction exhibits a high or low current state, which can be controlled by external electric fields. Considering different regimes, which range from weak to strong hydrogen bonds in the proton transfer complex and comprise situations with high and low barriers, necessary preconditions to achieve control are analyzed. The results show that systems with a weak hydrogen bond and a significant energy barrier for the proton transfer can be used as molecular transistors or diodes.