  Kinetic Monte Carlo (KMC) simulations have been previously used to model and
understand a wide range of behaviors in bulk heterojunction (BHJ) organic
photovoltaic devices, from fundamental mechanisms to full device performance.
One particularly unique and valuable aspect of this type of modeling technique
is the ability to explicitly implement models for the bicontinuous
nanostructured morphology present in these devices. For this purpose, an
Ising-based method for creating model BHJ morphologies has become prevalent.
However, this technique can be computationally expensive, and a detailed
characterization of this method has not yet been published. Here, we perform a
thorough characterization of this method and describe how to efficiently
generate controlled model BHJ morphologies. We show how the interaction energy
affects the tortuosity of the interconnected domains and the resulting charge
transport behavior in KMC simulations. We also demonstrate how to dramatically
reduce calculation time by several orders of magnitude without detrimentally
affecting the resulting morphologies. In the end, we propose standard
conditions for generating model morphologies and introduce a new open-source
software tool. These developments to the Ising method provide a strong
foundation for future simulation and modeling of BHJ organic photovoltaic
devices that will lead to a more detailed understanding of the important link
between morphological features and device performance.
