Abstract
We use a combination of molecular dynamics simulations and density functional theory calculations to investigate the energetic disorder in fullerene systems. We show that the energetic disorder evaluated from an ensemble average contains contributions of both static origin (time-independent, due to loose packing) and dynamic origin (time-dependent, due to electron-vibration interactions). In order to differentiate between these two contributions, we compare the results obtained from an ensemble average approach with those derived from a time average approach. It is found that in both amorphous C-60 and C-70 bulk systems, the degrees of static and dynamic disorder are comparable, while in the amorphous PC61BM and PC71BM systems, static disorder is about twice as large as dynamic disorder.