Acenaphtho[1, 2- k]fluoranthene-Fused Diimide Derivatives: An Investigation of the Relationship Between Molecular Structure and Device Performance.

Organic electron-acceptor materials play an important role in organic electronics, especially in organic bulk heterojunction (BHJ) solar cells. Recently, many non-fullerene small molecular acceptors have been developed, in which aromatic fused-imides were proven to be a promising family of excellent electron acceptors. We developed a series of acenaphtho[1,2- k]fluoranthene-fused diimides, AFIs ( AFI1, AFI2 and AFI3), employing the Diels-Alder reaction as the crucial synthetic step. With electron-withdrawing diimide groups in their large conjugated backbone, AFIs display a LUMO level around −3.50 eV. These AFI compounds were used as the electron acceptors to fabricate organic photovoltaic devices. The power conversion efficiency (PCE) of up to 2.37 % was achieved with a high open-circuit voltage ( V_oc) up to 0.96 V. [ABSTRACT FROM AUTHOR]