Abstract
We investigate mixtures of fullerenes and fullerene derivatives, the most commonly used electron accepting materials in organic solar cells, by using a combination of molecular dynamics and density functional theory methods. Our goal is to describe how mixing affects the molecular packing, mechanical properties, and electronic parameters (site energy disorder, electronic couplings) of interest for solar-cell applications. Specifically, we consider mixtures of: (i) C-60 and C-70; (ii) C-60, C-70, and C-84, and (iii) PC61BM and PC71BM.