Simultaneously Enhancing the <i>J</i><sub>sc</sub> and <i>V</i><sub>oc</sub> of Ternary Organic Solar Cells by Incorporating a Medium-Band-Gap Acceptor
Min Zhang, Min Zeng, Xiong Deng, Zhijie Zhou, Xiaoxiao Tan, Songting Tan, Bin Zhao, Jianqi Zhang, Yingping Zou
Abstract
Ternary organic solar cells (OSCs) are fabricated with a PM6:Y6 blend film as the host system and a medium-band-gap (MBG) acceptor (BTIC-Cl) with a high-lying lowest unoccupied molecular orbital (LUMO) energy level as the third component. The ternary blend film PM6:Y6:BTIC-Cl (1:1.2:0.2, wt/wt) possesses a more favorable morphology, better ordered face-on π–π stacking, higher charge mobilities, and more balanced charge transfer than the binary blend films and other ternary blend films. As a result, the ternary OSC with the ratio of 1:1.2:0.2 shows an impressive power conversion efficiency of 16.60% with synchronously enhanced Jsc of 27.25 mA cm–2 and Voc of 0.86 V, which are distinctly superior to those of the binary OSCs based on PM6:Y6 (15.50%) and PM6:BTIC-Cl (12.66%). These results provide an insight into the role of an MBG small-molecule acceptor with a high-lying LUMO energy level in ternary OSCs.