The role of donor-acceptor interfacial charge-transfer (CT) electronic states in photoelectric energy conversion in organic solar cells (Conference Presentation)

A critical component of any donor-acceptor (D-A) bulk heterojunction organic solar cell is the appearance of inter-molecular charge-transfer (CT) electronic states at their D-A interfaces. These electronic states play a determining role in the photo-physical processes that transform the energy of the absorbed sunlight into electrical power. Here, through integrated multiscale theoretical simulations, we have illustrated how factors such as the details of the molecular packing at the D-A interfaces, the electronic polarization effects, and the extent of electron/hole delocalization around the interface impact the nature of the CT states. Moreover, we have also discussed how the hybridization between the CT and local-exciton (LE) states impacts the spectroscopy characteristics of D-A blends, the recombination rates and consequently the voltage losses, which need to be minimized.