  Hot charge carrier extraction from metallic nanostructures is a very
promising approach for applications in photo-catalysis, photovoltaics and
photodetection. One limitation is that many metallic nanostructures support a
single plasmon resonance thus restricting the light-to-charge-carrier activity
to a spectral band. Here we demonstrate that a monolayer of plasmonic
nanoparticles can be assembled on a multi-stack layered configuration to
achieve broad-band, near-unit light absorption, which is spatially localised on
the nanoparticle layer. We show that this enhanced light absorbance leads to
$\sim$ 40-fold increases in the photon-to-electron conversion efficiency by the
plasmonic nanostructures. We developed a model that successfully captures the
essential physics of the plasmonic hot-electron charge generation and
separation in these structures. This model also allowed us to establish that
efficient hot carrier extraction is limited to spectral regions where the
photons possessing energies higher than the Schottky junctions and the
localised light absorption of the metal nanoparticles overlap.
