posted on 2024-02-05, 14:06authored byAngela
L. Paoletta, Latha Venkataraman
Biased
metal–molecule–metal junctions emit light
through electroluminescence, a phenomenon at the intersection of molecular
electronics and nanoplasmonics. This can occur when the junction plasmon
mode is excited by inelastic electron current fluctuations. Here,
we simultaneously measure the conductance and electroluminescence
intensity from single-molecule junctions with time resolution in a
solution environment at room temperature. We use current versus bias
data to determine the molecular junction transport parameters and
then relate these to the expected current shot noise. We find that
the electroluminescence signal accurately matches the theoretical
prediction of shot-noise-driven emission in a large fraction of the
molecular junctions studied. This introduces a novel experimental
method for qualitatively estimating finite-frequency shot noise in
single-molecule junctions under ambient conditions. We further demonstrate
that electroluminescence can be used to obtain the level alignment
of the frontier orbital dominating transport in the molecular junction.