Structure, Electronic, and Charge Transfer Properties of Organic Photovoltaics from Density Functional Theory Methods

Organic photovoltaic (OPV) cells have attracted considerable attention as renewable energy source with potential for large scale deployment. Among the most efficient OPVs are so-called bulk-heterojunction (BHJ) cells in which the active material consists of an electron donor and electron acceptor material. In this chapter we review how density functional theory (DFT) methods can be employed to characterize interfacial properties, UV-Vis absoprtion spectra, and photoinduced charge separation in BHJ-OPV donor-acceptor complexes based on semiconducting polymers as donor and fullerene derivatives as acceptor. The methods presented here are transferable also to other donor acceptor materials.