# Light-driven molecular switching achieves 6-order magnitude conductance change in OPE dimers

## TL;DR

Researchers showed that light can switch the electrical conductance of OPE molecules by up to a million times, using azobenzene isomerization.

## Contribution

A 6-order magnitude conductance change in OPE dimers via light-driven isomerization of azobenzene.

## Key findings

- Light-induced E to Z isomerization of azobenzene alters quantum interference in OPE dimers.
- Conductance on–off ratio reaches up to 6 orders of magnitude.
- This performance matches the best molecular switches currently available.

## Abstract

Functional molecular devices have garnered significant research interest over the past ten years due to their promising potential for applications in both non-volatile memory and novel computing architectures. In this work, we investigate light-induced switching of electrical conductance in linear oligo(phenylene-ethylene)-based (OPE) molecules that incorporate an azobenzene bridging unit to form OPE dimers. We demonstrate that a light stimulus can cause electron transport through the molecule to switch from constructive to destructive quantum interference through an E to Z (trans to cis) azobenzene isomerisation, leading to an on–off conductance ratio of up to 6 orders of magnitude, which is comparable with the best molecular switches obtained to date.

(a) OPE3 meta and para-junctions. (b) Transmission T(E) vs. energy.