Enhanced Thermoelectric Performance in Hybrid Nanoparticle--Single Molecule Junctions

TL;DR

This paper proposes hybrid nanoparticle-molecule junctions as highly efficient thermoelectric converters, demonstrating significant improvements in thermopower and figure of merit through a generic model, robustness, and realistic parameters.

Contribution

It introduces a novel hybrid nanoparticle-molecule junction design that significantly enhances thermoelectric performance compared to conventional molecular junctions.

Findings

Thermopower can reach hundreds of microvolts per Kelvin.

Thermoelectric figure of merit approaches close to one.

Performance remains robust under disorder and decoherence.

Abstract

It was recently suggested that molecular junctions would be excellent elements for efficient and high-power thermoelectric energy conversion devices. However, experimental measurements of thermoelectric conversion in molecular junctions have indicated rather poor efficiency, raising the question of whether it is indeed possible to design a setup for molecular junctions that will exhibit enhanced thermoelectric performance. Here we suggest that hybrid single-molecule nanoparticle junctions can serve as efficient thermoelectric converters. The introduction of a semiconducting nanoparticle introduces new tuning capabilities, which are absent in conventional metal-molecule-metal junctions. Using a generic model for the molecule and nanoparticle with realistic parameters, we demonstrate that the thermopower can be of the order of hundreds of microvolts per degree Kelvin, and that the thermoelectric figure of merit can reach values close to one, an improvement of four orders of magnitude improvement over existing measurements. This favorable performance persists over a wide range of experimentally relevant parameters, and is robust against disorder (in the form of surface-attached molecules) and against electron decoherence at the nanoparticle molecule interface.