CHAPTER 10: Charge Generation, Recombination and Transport in Organic Solar Cells

In this chapter we review the current understanding in the organic solar cell (OSC) research community on the three critical processes in OSC device operation: charge generation, charge recombination and charge transport. The charge generation process in OSCs can be described by either the classical exciton theory or the ultrafast charge generation theory; the former is still widely accepted in the community, however the latter has been steadfastly gaining more support in recent years. The charge recombination process in OSC devices is predominantly bimolecular recombination, which is small yet not negligible in high efficiency OSC devices. The charge transport process in OSCs is strongly affected by charge trapping states, however the exact physics is still not totally clear and requires deeper understanding.