Reinder Coehoorn: Charge transport and excitonic processes in disordered organic semiconductors - which molecular-scale details are relevant?

Simulation methods of the charge transport and excitonic processes in disordered organic semiconductor materials necessarily neglect details of the molecular-scale structure and the electronic interactions. Obtaining the most relevant parameters in a well-resolved way from experiment is often difficult. Therefore, one may ask to what extent simulations of e.g. the performance of light-emitting diodes (OLEDs) and organic photovoltaic (OPV) devices are predictive, and how relevant molecular-scale details can be deduced from more advanced simulations and experiments. In this talk, recent work which aims at the development of really predictive models is discussed: (i). Ab initio modeling of the hole mobility in application-relevant small-molecule OLED materials, including the positional, energetic and transfer integral disorder, and (ii). Experimental studies of triplet exciton diffusion and annihilation in phosphorescent OLED materials. In both cases, the use of advanced kinetic Monte Carlo simulations is shown to be crucial as a means to understand the interplay between all processes.