Synergistically manipulating the shape of alkyl-chain and asymmetric side groups of non-fullerene acceptors enables organic solar cells to reach 18.5% efficiency
Xinyu Tong,
Zhenyu Chen,
Jingyu Shi,
Jinfeng Ge,
Wei Song,
Yuanyuan Meng,
Ziyi Ge
Affiliations
Xinyu Tong
Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Zhejiang 315201, PR China; Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, PR China
Zhenyu Chen
Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Zhejiang 315201, PR China; Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, PR China
Jingyu Shi
Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Zhejiang 315201, PR China; Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, PR China
Jinfeng Ge
Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Zhejiang 315201, PR China
Wei Song
Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Zhejiang 315201, PR China
Yuanyuan Meng
Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Zhejiang 315201, PR China
Ziyi Ge
Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Zhejiang 315201, PR China; Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, PR China; Corresponding author.
Side-chain modification and asymmetric design for non-fullerene acceptors (NFAs) have been proven to be effective methods for harvesting high-performance organic solar cells (OSCs). Combining the two molecular design strategies, we adopted phenyl chain and alkyl chains with different shapes to develop two novel asymmetric NFAs, named BTP-P2EHC11 and BTP-P2EHC2C4. Compared with BTP-P2EHC2C4 attached 2-ethylhexyl side chain, BTP-P2EHC11 with linear alkyl side chain have slightly red-shifted absorption and intensive absorption strength. Moreover, the PM6:BTP-P2EHC11 blend film presents higher and more balanced charge mobilities, reducing charge recombination, tighter intermolecular packing and more favorable fibrous network morphology with appropriate phase separation than PM6:BTP-P2EHC2C4, which lead to significantly enhanced short-circuit current density (JSC) of PM6:BTP-P2EHC11-based devices. Thus, the OSCs based on PM6:BTP-P2EHC11 achieve a superior power conversion efficiency (PCE) of 18.50% with a good trade-off among open-circuit voltage (VOC) of 0.876 V, JSC of 26.85 mA cm−2 and fill factor (FF) of 78.65%, while PM6:BTP-P2EHC2C4-based device exhibits a lower PCE of 17.49%. Our investigation elucidates that the combination of finely optimizing the shape of alkyl-chain and asymmetric side groups of NFAs could pave a promising avenue toward morphology optimization and performance promotion of OSCs.
