Over 18% ternary polymer solar cells enabled by a terpolymer as the third component

“Ternary blending” and “random terpolymerization” strategies have both proven effective for enhancing the performance of organic solar cells (OSCs). However, reports on combination two remain rare. Here, a terpolymer PM6-Si30 was constructed by inserting chlorine alkylsilyl-substituted benzodithiophene (BDT) unit (0.3 equivalent) into state-of-the-art polymer PM6. The exhibitsadeep highest-occupied-molecular-orbital energy good miscibility with PM6 BTP-eC9 (C9) enables its use as third component PM6:PM6-Si30:C9 bulk-heterojunction OSCs. resulting exhibit maximum power conversion efficiency (PCE) 18.27%, which is higher than that obtained optimized control binary PM6:C9-based OSC (17.38%). enhanced attributed to improved charge transport, favorable molecular arrangement, reduced loss suppressed bimolecular recombination. work demonstrates potential random in OSCs highlights new strategy construction ternary system photovoltaic performance.