Premium
Regioregular Narrow‐Bandgap n‐Type Polymers with High Electron Mobility Enabling Highly Efficient All‐Polymer Solar Cells
Author(s) -
Sun Huiliang,
Liu Bin,
Ma Yunlong,
Lee JinWoo,
Yang Jie,
Wang Junwei,
Li Yongchun,
Li Bangbang,
Feng Kui,
Shi Yongqiang,
Zhang Baohua,
Han Dongxue,
Meng Hong,
Niu Li,
Kim Bumjoon J.,
Zheng Qingdong,
Guo Xugang
Publication year - 2021
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.202102635
Subject(s) - materials science , imide , band gap , polymer , electron mobility , ternary operation , electron acceptor , optoelectronics , homo/lumo , polymer chemistry , photochemistry , organic chemistry , composite material , molecule , chemistry , computer science , programming language
Narrow‐bandgap n‐type polymers with high electron mobility are urgently demanded for the development of all‐polymer solar cells (all‐PSCs). Here, two regioregular narrow‐bandgap polymer acceptors, L15 and MBTI, with two electron‐deficient segments are synthesized by copolymerizing two dibrominated fused‐ring electron acceptors (FREA) with distannylated aromatic imide, respectively. Taking full advantage of the FREA and the imide, both polymer acceptors show narrow bandgap and high electron mobility. Benefiting from the more extended absorption, better backbone ordering, and higher electron mobility than those of its regiorandom analog, the L15‐based all‐PSC yields a high power conversion efficiency (PCE) of 15.2% when blended with the polymer donor PM6. More importantly, MBTI incorporating a benzothiophene‐core FREA segment shows relatively higher frontier molecular orbital levels than L15, forming a cascade‐like energy level alignment with L15 and PM6. Based on this, ternary all‐PSCs are designed where MBTI is introduced as a guest into the PM6:L15 host system. Thanks to further optimal blend morphology and more balanced charge transport, the PCE is improved up to 16.2%, which is among the highest values for all‐PSCs. The results demonstrate that combining an FREA and an aromatic imide to construct regioregular narrow‐bandgap polymer acceptors provides an effective approach to fabricate highly efficient all‐PSCs.