Ternary Organic Photovoltaic Cells Exhibiting 17.59% Efficiency with Two Compatible Y6 Derivations as Acceptor

Efficient organic photovoltaic cells (OPVs) are fabricated using two structurally similar Y6 derivations (BTP-BO-4F and Y6-1O) as acceptor and PM6 as donor. The two binary OPVs exhibit a high fill factor (FF) (>76%), the complementary short-circuit-current density (J_SC) and open-circuit voltage (V_OC). The high FFs of binary OPVs indicate the good compatibility of corresponding materials to form efficient charge transport channels. A power conversion efficiency (PCE) of 17.59% is obtained from ternary OPVs with 15 wt% Y6-1O in acceptors, benefiting from the simultaneously improved J_SC of 26.13 mA cm⁻², a V_OC of 0.860 V, and an FF of 78.26%. The values of V_OC of ternary OPVs can be gradually increased along with the incorporation of Y6-1O, suggesting the preferred formation of an alloyed state between BTP-BO-4F and Y6-1O due to their good compatibility. Meanwhile, the cascaded energy levels of BTP-BO-4F and Y6-1O can form efficient electron transport channels in ternary active layers. The main contribution of Y6-1O can be summarized as enhancing photon harvesting, optimizing phase separation, and adjusting molecular arrangement. The experimental results may provide new insight on developing efficient ternary OPVs by selecting two well-compatible acceptors.