Exciton transport in organic microcavities in the strong coupling regime

Abstract

Exciton transport plays a crucial rule both in natural phenomena, such as heat transport or photosynthesis, where energy has to be transported to a reaction center, and in artificial devices such as exciton transistors or organic solar cells, whose power conversion efficiency can be improved significantly when the exciton diffusion length is increased. Recently, it was demonstrated that exciton conductance in organic materials can be dramatically enhanced when the molecules are strongly coupled to an electromagnetic mode, due to the formation of collective polaritonic modes in the strong coupling regime [1]. However, there are a number of open question, such as the influence of having more than a single electromagnetic mode [2] and the role of intramolecular vibrations [3]. Inspired by these results, we first [4] address the problem of quantum emitters strongly coupled to a multimode field, which is a more realistic approach when analysing large nanostructures such as nanowires. We study the effects of number of modes and cavity dispersion on the formation of a dark-state channel and its effect on the transport efficiency. We next turn to study the influence of intramolecular vibrational modes on spectroscopic and exciton transport properties in strongly-coupled organic microcavities [5]. By including the intramolecular vibrations explicitly and treating the exciton-vibration coupling and exciton-cavity coupling at finite temperatures on an equal footing, we construct a microscopic theory of vibration-induced effects in the strong coupling regime.