Towards Molecular Dynamics Modelling of Mesoscale Bulk Heterojunction Morphologies

The performance of organic photovoltaics (OPVs) based on solution processed polymer:fullerene or polymer:polymer active layers is crucially dependent on the 3D morphology of the mesoscale bulk heterojunction. Here, we use Molecular Dynamics (MD) simulations of single indacenodithiophene-co-benzothiadiazole (IDTBT) polymers in solution to study their persistence lengths, since long persistence lengths are believed to be crucial for high charge mobilities and strong optical absorption.

Furthermore, we present initial efforts towards simulating the dynamics of blend microstructure formation at reasonable computational costs by employing coarse-grained (CG) MD models, i.e. describing several atoms in a unified manner. Through this, we hope to aid the interpretation of experimental 3D imaging and refine the current, predominantly phenomenological, hypotheses which are based on indirect experimental probing of 3D morphology.