Small-molecule, nonfullerene acceptors for polymer bulk heterojunction organic photovoltaics

In the field of polymer bulk-heterojunction organic photovoltaics, fullerenes and fullerene derivatives clearly play the dominant role as acceptor materials. Recently, a number of research efforts have focused on the development of new small-molecule acceptors for this device configuration. Although few materials prepared to-date have demonstrated power conversion efficiencies close to those achieved with fullerenes, numerous design rules and some interesting new materials classes have been explored. This short review will highlight the progress toward higher efficiency in nonfullerene small-molecule acceptors for organic solar cells.