Arrays of size-dispersed ZnSe quantum dots as artificial antennas: Role of quasi-coherent regime and in-gap states of excitons for enhanced light harvesting and energy transfer

Abstract

Densely packed thin films of semiconductor quantum dots (QDs) shows specific the optoelectronic properties originate from the QDs coupling that may pave the way for new controllable building blocks for quantum technologies and light-harvesting complexes in natural photosynthetic systems and photovoltaic cells. In this work we were compared the optical properties and an excitonic energy transfer (EET) process in an aqueous solutions and dense packed films of ZnSe QDs with a narrow size distribution. An unexpectedly large nonlinear increase in the photoluminescence (PL) intensity was detected in QDs films with the decrease of an excitation energy that can be explained by resonantly transferred of EET through the quantum states. We found that with decreasing of the excitation energy form of quasi-coherent regime of excitons and the quantum and surface PL emission increases by a factor ∼10 and ∼6, respectively, due to increasing the EET rate.