Prediction of Structure and Charge Transport in Itic-Derived Electron Acceptors for Plastic Solar Cells

The goal of this project is to help experimentalists choose molecules and conditions optimized for synthesizing high-efficiency solar cells made from organic components. The structure and packing of molecules in organic photovoltaics (OPVs) influences charge transport and overall solar cell efficiency. We develop new software for initializing, simulating, and analyzing the morphologies of candidate OPV compounds. Here we focus on using molecular dynamics (MD) simulations to predict the thermodynamically stable morphologies of electron acceptor molecules ITIC, ITIC-F4, and CZTPTZ8FITIC. The equilibrated molecular packings from the MD simulations are used to predict charge transport properties and for model validation when experimental measurements are available. We discuss the thermodynamic conditions that we observe correlate with assembly of morphologies with higher charge transport. We find that these three ITIC-derived electron acceptors assemble structures with low long-range order and that their favorable charge transport properties may arise from the isotropic network of pi-stacked connections between molecules.