Over 18% ternary polymer solar cells enabled by a terpolymer as the third component
Wenhong Peng, Yuanbao Lin, Sang Young Jeong, Zewdneh Genene, Artiom Magomedov, Han Young Woo, Cailing Chen, Wandi Wahyudi, Qiang Tao, Jiyong Deng, Yu Han, Vytautas Getautis, Weiguo Zhu, Thomas D. Anthopoulos, Ergang Wang
Abstract
“Ternary blending” and “random terpolymerization” strategies have both proven effective for enhancing the performance of organic solar cells (OSCs). However, reports on the combination of the two strategies remain rare. Here, a terpolymer PM6-Si30 was constructed by inserting chlorine and alkylsilyl-substituted benzodithiophene (BDT) unit (0.3 equivalent) into the state-of-the-art polymer PM6. The terpolymer exhibitsadeep highest-occupied-molecular-orbital energy and good miscibility with both PM6 and BTP-eC9 (C9) and enables its use as a third component into PM6:PM6-Si30:C9 bulk-heterojunction for OSCs. The resulting cells exhibit maximum power conversion efficiency (PCE) of 18.27%, which is higher than that obtained for the optimized control binary PM6:C9-based OSC (17.38%). The enhanced performance of the PM6:PM6-Si30:C9 cells is attributed to improved charge transport, favorable molecular arrangement, reduced energy loss and suppressed bimolecular recombination. The work demonstrates the potential of random terpolymer as a third component in OSCs and highlights a new strategy for the construction of a ternary system with improved photovoltaic performance.