Achieving 17.4% Efficiency of Ternary Organic Photovoltaics with Two Well-Compatible Nonfullerene Acceptors for Minimizing Energy Loss

A power conversion efficiency (PCE) of 16.2% is achieved in PM6:BTP-4F-12 based organic photovoltaics (OPVs). On the basis of efficient binary OPVs, a series of ternary OPVs are constructed by incorporating MeIC as the third component. The open circuit voltages (V(OC)s) of ternary OPVs can be gradually increased along with the incorporation of MeIC, suggesting the formation of an alloy state between BTP-4F-12 and MeIC with good compatibility. The energy loss (E-loss) of ternary OPVs can be decreased compared with that of two binary OPVs, contributing to theV(OC)improvement of ternary OPVs. The short circuit current density (J(SC)) and fill factor (FF) of ternary OPVs can also be simultaneously enhanced with MeIC content up to 10 wt% in acceptors, leading to 17.4% PCE of the optimized ternary OPVs. TheJ(SC)and FF improvement of ternary OPVs is thought to result from the optimized ternary active layers with more efficient photon harvesting, exciton dissociation and charge transport. The 17.4% PCE and 79.2% FF is among the top values of ternary OPVs. This work indicates that a ternary strategy is an emerging method to simultaneously minimizeE(loss)and optimize photon harvesting as well as improve the morphology of active layers for realizing performance improvement for OPVs.