Control and enhancement of single-molecule electroluminescence through strong light-matter coupling

TL;DR

This paper demonstrates that strong light-matter coupling in plasmonic nanocavities can enhance electroluminescence efficiency in single-molecule junctions by controlling excited state formation, offering new design principles for molecular optoelectronics.

Contribution

It introduces a method to improve electroluminescence efficiency in single-molecule junctions through strong light-matter coupling and state control, advancing molecular optoelectronic device design.

Findings

Enhanced electroluminescence efficiency via strong coupling

Selective control of excited state formation in junctions

Discussion of polaritonic states' role in efficiency

Abstract

The energetic positions of molecular electronic states at molecule/electrode interfaces are crucial factors for determining the transport and optoelectronic properties of molecular junctions. Strong light--matter coupling offers a potential for manipulating these factors, enabling to boost in the efficiency and versatility of these junctions. Here, we investigate electroluminescence from single-molecule junctions in which the molecule is strongly coupled with the vacuum electromagnetic field in a plasmonic nanocavity. We demonstrate an improvement in the electroluminescence efficiency by employing the strong light--matter coupling in conjunction with the characteristic feature of single-molecule junctions to selectively control the formation of the lowest-energy excited state. The mechanism of efficiency improvement is discussed based on the energetic position and composition of the formed polaritonic states. Our findings indicate the possibility to manipulate optoelectronic conversion in molecular junctions by strong light--matter coupling and contribute to providing design principles for developing efficient molecular optoelectronic devices.