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

摘要

A molecular wire containing an emitting molecular center is controllablysuspended between the plasmonic electrodes of a cryogenic scanning tunnelingmicroscope. Passing current through this circuit generates an ultra narrow-lineemission at an energy of ? 1.5 eV which is assigned to the fluorescence of themolecular center. Control over the linewidth is obtained by progressivelydetaching the emitting unit from the surface. The recorded spectra also revealseveral vibronic peaks of low intensities that can be viewed as a fingerprintof the emitter. Surface-plasmon localized at the tip-sample interface are shownto play a major role on both excitation and emission of the molecular excitons.