A 19% efficient and stable organic photovoltaic device enabled by a guest nonfullerene acceptor with fibril-like morphology

A nonfullerene acceptor, isoIDITC, capable of exhibiting fibril-like morphology, is utilized as a third component in organic photovoltaic devices. A power conversion efficiency of 19% is achieved in ternary PM6:BTP-eC9:isoIDITC bulk-heterojunction devices.