  The interface between a liquid and a solid is the location of plethora of
intrincate mechanisms at the nanoscale, at the root of their specific emerging
properties in natural processes or technological applications. However, while
the structural properties and chemistry of interfaces have been intensively
explored, the effect of the solid-state electronic transport at the fluid
interface has been broadly overlooked up to now. It has been reported that
water flowing against carbon-based nanomaterials, such as carbon nanotubes or
graphene sheets, does induce electronic currents, but the mechanism at stake
remains controversial. Here, we unveil the molecular mechanisms underlying the
hydro-electronic couplings by investigating the electronic conversion under
flow at the nanoscale. We use a tuning fork-Atomic Force Microscope (AFM) to
deposit and displace a micrometric droplet of both ionic and non-ionic liquids
on a multilayer graphene sample, while recording the electrical current across
the carbon flake. We report measurements of an oscillation-induced current
which is several orders of magnitude larger than previously reported for water
on carbon , and further boosted by the presence of surface wrinkles on the
carbon layer. Our results point to a peculiar momentum transfer mechanism
between fluid molecules and charge carriers in the carbon walls mediated by
phonon excitations in the solid. Our findings pave the way for active control
of fluid transfer at the nanoscale by harnessing the complex interplay between
collective excitations in the solid and the molecules in the fluid.
