Narrow-line single-molecule transducer between electronic circuits and surface plasmons

TL;DR

This paper demonstrates a molecular wire-based transducer that couples electronic circuits to surface plasmons, enabling narrow-line emission control at cryogenic temperatures with potential applications in nanoscale photonics.

Contribution

It introduces a controllable single-molecule transducer bridging electronic circuits and surface plasmons, with tunable emission linewidth and detailed spectroscopic analysis.

Findings

Narrow-line emission at ~1.5 eV observed from molecular wire.

Control of linewidth achieved by detaching the emitter from surface.

Surface plasmons significantly influence excitation and emission processes.

Abstract

A molecular wire containing an emitting molecular center is controllably suspended between the plasmonic electrodes of a cryogenic scanning tunneling microscope. Passing current through this circuit generates an ultra narrow-line emission at an energy of ? 1.5 eV which is assigned to the fluorescence of the molecular center. Control over the linewidth is obtained by progressively detaching the emitting unit from the surface. The recorded spectra also reveal several vibronic peaks of low intensities that can be viewed as a fingerprint of the emitter. Surface-plasmon localized at the tip-sample interface are shown to play a major role on both excitation and emission of the molecular excitons.