Indacenodithiophene-Based Medium-Bandgap Guest Acceptor Enables High-Efficiency Ternary Organic Solar Cells.

The ternary organic solar cells (OSCs) have been proven to be an effective strategy for achieving high power conversion efficiency (PCE), exhibiting substantial potential for continuous enhancement of device performance. In this work, a novel nonfullerene acceptor, IDT-FN, is developed utilizing a renowned indacenodithiophene (IDT) core and moderately intense electron-withdrawing terminal groups, serving as the third component in ternary OSCs. IDT-FN demonstrates excellent complementary light absorption and cascaded energy levels with the host materials D18 and CH-6F, resulting in enhanced photon harvesting and charge transport within the ternary blend.