Engineering the thermopower in semiconductor-molecule junctions: towards high thermoelectric efficiency at the nanoscale

TL;DR

This paper explores a method to enhance thermoelectric efficiency in molecular junctions by chemically tuning molecular states and using semiconducting electrodes, aiming for high thermopower and figures of merit.

Contribution

It introduces a combined approach of chemical tuning and semiconducting electrodes to optimize thermoelectric performance in molecular junctions.

Findings

Large thermopower achievable in molecular junctions.

Suppression of electron-like contributions improves efficiency.

Potential for high figures of merit in designed junctions.

Abstract

We propose a possible route to achieve high thermoelectric efficiency in molecular junctions by combining a local chemical tuning of the molecular electronic states with the use of semiconducting electrodes. The former allows to control the position of the HOMO transmission resonance with respect to the Fermi energy while the latter fulfills a twofold purpose: the suppression of electron-like contributions to the thermopower and the cut-off of the HOMO transmission tails into the semiconductor band gap. As a result a large thermopower can be obtained. Our results strongly suggest that large figures of merit in such molecular junctions can be achieved.