  We report on the luminescence's life-time and line-width from an array of
individual quantum dots; these were interfaced with graphene surface guides or
dispersed on a metal film. Our results are consistent with screening by charge
carriers. Fluorescence quenching is typically mentioned as a sign that
chromophores are interfacing a conductive surface; we found that QD interfaced
with conductive layers exhibited shorter life-time and line-broadening but not
necessarily fluorescence quenching as the latter may be impacted by molecular
concentration, reflectivity and conductor imperfections. We also comment on
selective life-time measurements, which, we postulate depend on the specifics
of the local density-of-states involved.
