Fluorescence decay rate statistics of a single molecule in a disordered cluster of nanoparticles

The statistical properties of the fluorescence lifetime of single emitters in disordered systems are discussed. The contribution of radiative and nonradiative processes to the spontaneous decay rate is analyzed using a simple analytical model, in full agreement with exact numerical simulations. The relative fluctuations of the decay rate are shown to exhibit two well-defined regimes dominated either by near-field scattering or by absorption processes. In both regimes, the averaged apparent quantum yield remains high enough to permit practical measurements. Lifetime fluctuations could thus be used a probe of the local environment in complex systems at the nanometer scale.