Lifetime and linewidth of individual quantum dots interfaced with graphene

We report on luminescence lifetimes and linewidths from an array of individual quantum dots (QDs) that were either interfaced with graphene surface guides or dispersed on aluminum electrodes. The observed fluorescence quenching is consistent with screening by charge carriers. Fluorescence quenching is typically mentioned as a sign that chromophores are interfacing with a conductive surface (metal or graphene); we find that the QDs interfaced with the metal film exhibit shortened lifetime 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 angle-dependent lifetime measurements, which we postulate depend on the specifics of the local density-of-states involved.