Modelling transport in nanoparticle organic solar cells using Monte Carlo methods

Water-based nanoparticle (NP) organic solar cells eliminate the need for harmful organic solvents during deposition. However, the core-shell NP structure should limit charge extraction resulting in poor performance. Here, we use dynamic Monte Carlo modelling to show that for optimised NP structures the core-shell character does not severely limit performance. Simulations further reveal that small NPs are more susceptible to extensive phase segregation, which diminishes charge carrier percolation pathways from the cores to the electrodes and thus inhibits charge extraction. Simulated performance behaviour was used to propose an explanation for the experimentally observed change in performance due to annealing.