Current induced light emission and light induced current in molecular tunneling junctions

TL;DR

This paper presents a model showing that light can induce current in unbiased molecular junctions with charge-transfer molecules and that bias can cause light emission, both observable with realistic parameters.

Contribution

It introduces a simple generic model demonstrating light-induced current and light emission in molecular tunneling junctions, a novel insight into their optoelectronic behavior.

Findings

Light-induced current occurs in unbiased junctions with charge-transfer molecules.

Bias can induce light emission exceeding molecular excitation energy.

Both effects are predicted to be observable with realistic parameters.

Abstract

The interaction of metal-molecule-metal junctions with light is considered within a simple generic model. We show, for the first time, that light induced current in unbiased junctions can take place when the bridging molecule is characterized by a strong charge-transfer transition. The same model shows current induced light emission under potential bias that exceeds the molecular excitation energy. Results based on realistic estimates of molecular-lead coupling and molecule-radiation field interaction suggest that both effects should be observable.