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Efficient, Thermally Stable, and Mechanically Robust All‐Polymer Solar Cells Consisting of the Same Benzodithiophene Unit‐Based Polymer Acceptor and Donor with High Molecular Compatibility
Author(s) -
Lee JinWoo,
Sun Cheng,
Ma Boo Soo,
Kim Hyeong Jun,
Wang Cheng,
Ryu Jong Min,
Lim Chulhee,
Kim TaekSoo,
Kim YunHi,
Kwon SoonKi,
Kim Bumjoon J.
Publication year - 2021
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.202003367
Subject(s) - materials science , polymer , thermal stability , acceptor , polymer solar cell , organic solar cell , polymerization , compatibility (geochemistry) , energy conversion efficiency , toughness , chemical engineering , polymer chemistry , composite material , optoelectronics , physics , engineering , condensed matter physics
All‐polymer solar cells (all‐PSCs) are a highly attractive class of photovoltaics for wearable and portable electronics due to their excellent morphological and mechanical stabilities. Recently, new types of polymer acceptors ( P A s) consisting of non‐fullerene small molecule acceptors (NFSMAs) with strong light absorption have been proposed to enhance the power conversion efficiency (PCE) of all‐PSCs. However, polymerization of NFSMAs often reduces entropy of mixing in PSC blends and prevents the formation of intermixed blend domains required for efficient charge generation and morphological stability. One approach to increase compatibility in these systems is to design P A s that contain the same building blocks as their polymer donor ( P D ) counterparts. Here, a series of NFSMA‐based P A s [P(BDT2BOY5‐X), (X = H, F, Cl)] are reported, by copolymerizing NFSMA (Y5‐2BO) with benzodithiophene (BDT), a common donating unit in high‐performance P D s such as PBDB‐T. All‐PSC blends composed of PBDB‐T P D and P(BDT2BOY5‐X) P A show enhanced molecular compatibility, resulting in excellent morphological and electronic properties. Specifically, PBDB‐T:P(BDT2BOY5‐Cl) all‐PSC has a PCE of 11.12%, which is significantly higher than previous PBDB‐T:Y5‐2BO (7.02%) and PBDB‐T:P(NDI2OD‐T2) (6.00%) PSCs. Additionally, the increased compatibility of these all‐PSCs greatly improves their thermal stability and mechanical robustness. For example, the crack onset strain (COS) and toughness of the PBDB‐T:P(BDT2BOY5‐Cl) blend are 15.9% and 3.24 MJ m –3 , respectively, in comparison to the PBDB‐T:Y5‐2BO blends at 2.21% and 0.32 MJ m –3 .