Radiative Decay of Quantum Dots in Dielectric Media: A New Approach to Models’ Validation Suitable for Emitters Showing Nonexponential Luminescence Decay

The radiative decay rate of various colloidal nanostructures depends on the refractive index of their environment due to local-field effects. This dependence is very material-specific and can be described by many different models. For various emerging colloidal nanostructures, it remains unknown if a particular model is appropriate until it is experimentally validated. The standard method, which has been used for validating models, applies only to colloidal nanostructures exhibiting single-exponential luminescence decays. In this way, many interesting nanostructures are eliminated from examinations, including different colloidal quantum dots, which very often show nonexponential luminescence decays. In this paper, we overcome this serious limitation. We describe a new method allowing for rigorous validation of different local-field models in the case of colloidal nanostructures characterized by nonexponential luminescence decays. Moreover, in contrast to the standard method, our new approach makes no assumptions about the effect of the dielectric environment on the nonradiative processes in colloidal nanostructures. In this paper, we use the new method to validate several local-field models, which have been used in the literature to describe colloidal semiconductor quantum dots.