Miscibility screening promotes the efficiency and stability of P3HT-based organic solar cells Special Issue:Emerging Investigators

The power conversion efficiency of organic photovoltaics(OPVs)has witnessed continuous breakthroughs in the past few years,mostly benefiting from the extensive use of a facile ternary blending strategy by blending the host polymer donor:small molecule acceptor mixture with a second small molecule acceptor.Nevertheless,this rather general strategy used in the well-known PM6 systems fails in constructing high-performance P3HT-based ternary OPVs.As a result,the efficiencies of all resulting ternary blends based on a benchmark host P3HT:ZY-4Cl and a second acceptor are no more than 8%.Employing the mutual miscibility of the binary blends as a guide to screen the second acceptor,here we were able to break the longstanding 10%-efficiency barrier of ternary OPVs based on P3HT and dual nonfullerene acceptors.With this rational approach,we identified a multifunctional small molecule acceptor BTP-2Br to simultaneously improve the photovoltaic performance in both P3HT and PM6-based ternary OPVs.Attractively,the P3HT:ZY-4Cl:BTP-2Br ternary blend exhibited a record-breaking efficiency of 11.41%for P3HT-based OPVs.This is the first-ever report that over 11%efficiency is achieved for P3HTbased ternary OPVs.Importantly,the study helps the community to rely less on trial-and-error methods for constructing ternary solar cells.