Indacenodifuran-Based Non-Fullerene Electron Acceptors for Efficient Polymer Solar Cells

Two indaceno[1,2-b:5,6-b']difuran-based non-fullerene acceptors (NFAs) IDF-IC and IDF-4F were designed and synthesized. IDF-IC and IDF-4F showed strong absorptions in the visible and near-infrared (NIR) region with narrow bandgaps of 1.56-1.62 eV. The power conversion efficiencies (PCEs) of PM6:IDF-IC and PM6:IDF-4F devices were 7.80% and 7.81%, respectively, with open-circuit voltages (V-oc's) of 0.905 and 0.736 V, short-circuit current densities (J(sc)'s) of 14.55 and 17.49 mA/cm(2), and fill factors (FFs) of 59% and 61%. These results demonstrate that the fused-ring furan-based NFAs could be one of the promising building blocks in constructing high performance NFAs.