Disorder effects in the electronic properties of organic solar cells

Organic solar cells have a complex physical structure that self-assembles from a solution of polymers and fullerenes into nanoscale domains. This so-called bulk heterojunction has enables organic solar cells to reach above 10% efficiency. The talk will focus on the role of localized electronic states arising from disorder and defects. Similar to the inorganic amorphous semiconductors, disorder introduces exponential band tails and deep traps in the electronic structure which play a central role in the electronic transport and recombination mechanisms. In addition, light-induced effects in organic solar cells are remarkably similar to the Staebler-Wronski effect in amorphous silicon.