Molecular dynamics simulations turn morphology understanding on its head

Low donor content solar cells utilising a fullerene acceptor are interesting as they have remarkably high open circuit voltages and reasonable efficiencies in spite the of the donor only being present in a few wt%. Various explanations of how they work have been put forward but in a recent paper COPE and colleagues have shown using molecular dynamics simulations that the donor materials are distributed in the films at a distance that can enable a percolation pathway for charges to be extracted in spite of their concentration being below the expected percolation limit.