Disorder effects in the electronic properties of organic solar cells

Abstract

Bulk heterojunction organic solar cells have a complex physical structure made up of nanoscale domains of donors and acceptors, each of which is a disordered material. Understanding the electronic properties has proved controversial, with several competing models of transport and recombination. The talk will focus on the role of localized electronic states introduced by the disorder or by impurities. Disorder introduces exponential band tails and deep traps in the electronic structure and experiments show that these play a central role in the electronic transport and recombination mechanisms. Trap creation induced by irradiation is also shown to cause degradation of some solar cells.