Recombination rates for single colloidal quantum dots near a smooth metal film

Abstract

This paper presents experimental distributions of recombination rates for excitons in individual CdSe-ZnS core-shell quantum dots separated from a smooth gold film by a nanometre-scale dielectric layer. By measuring emission kinetics as a function of time, we obtain intrinsic recombination rates for single quantum dots. The distribution of recombination rates broadens and its maximum value increases as the separation between the dots and the metal decreases. The results agree with a semiclassical model that takes into account the randomly oriented two-dimensional dipole moments of the quantum dots.