Over 15% Efficiency in Ternary Organic Solar Cells by Enhanced Charge Transport and Reduced Energy Loss
Hongtao Wang, Zhuohan Zhang, Jiangsheng Yu, Po‐Chen Lin, Chu‐Chen Chueh, Xin Liu, Shun Guang, Shenya Qu, Weihua Tang
Abstract
In this study, an efficient ternary bulk-heterojunction (BHJ) organic solar cell (OSC) is demonstrated by incorporating two acceptors, PC61BM and ITC6-4F, with a polymer donor (PM6). This reveals that the addition of PC61BM not only enhances the electron mobility of the derived BHJ blend but also facilitates exciton dissociation, resulting in a more balanced charge transport alongside with reduced trap-assisted charge recombination. Consequently, as compared to the pristine PM6/ITC6-4F device, the optimal ternary OSC is revealed to deliver an improved power conversion efficiency (PCE) of 15.11% with a boosted JSC, VOC, and fill factor (FF) simultaneously. The resultant VOC and FF are among the highest values recorded in the literature for the ternary OSCs with a PCE exceeding 15%. This result thus suggests that besides improving the charge transport characteristics in devices, incorporating a fullerene derivative as part of the acceptor can also improve the resultant VOC, which can reduce the energy loss to realize efficient organic photovoltaics.