Kinetic Monte Carlo modeling on organic solar cells: Domain size, donor-acceptor ratio and thickness

Organic solar cells have received a lot of attention in the last few decades. Extensive experimental work has been conducted to improve organic solar cell performance. However, a much more realistic and accurate model needs to be developed that can simulate and predict photovoltaic performance for organic solar cells. In this work, a Kinetic Monte Carlo (KMC) model was developed to simulate the morphological variation of organic solar cells and its effects on photovoltaic parameters. This model is currently based on P3HT: PCBM system and can be easily extended to any low bandgap polymer solar cells. The novelty and advancement of this work is that this new KMC simulation model can simulate three different parameters including domain size, donor-acceptor ratio and active layer thickness in the same model and predict the efficiency of organic solar cells on the variation of these parameters. This simulation model has been validated by photovoltaic performance from fabricated devices. The optimized parameters of simulation and fabrication are correlated and the simulation results are in agreement with the experimental results. With the assistance from this model, researchers may be able to simplify the complex fabrication processing by identifying optimal conditions such as domain size, donor-acceptor ratio and active layer thickness via this new simulation model.