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Barrierless Free Charge Generation in the High‐Performance PM6:Y6 Bulk Heterojunction Non‐Fullerene Solar Cell
Author(s) -
PerdigónToro Lorena,
Zhang Huotian,
Markina Anastasia,
Yuan Jun,
Hosseini Seyed Mehrdad,
Wolff Christian M.,
Zuo Guangzheng,
Stolterfoht Martin,
Zou Yingping,
Gao Feng,
Andrienko Denis,
Shoaee Safa,
Neher Dieter
Publication year - 2020
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.201906763
Subject(s) - materials science , fullerene , organic solar cell , photocurrent , heterojunction , dissociation (chemistry) , polymer solar cell , excitation , chemical physics , solar cell , coulomb , optoelectronics , polymer , chemistry , organic chemistry , composite material , electron , physics , quantum mechanics , electrical engineering , engineering
Organic solar cells are currently experiencing a second golden age thanks to the development of novel non‐fullerene acceptors (NFAs). Surprisingly, some of these blends exhibit high efficiencies despite a low energy offset at the heterojunction. Herein, free charge generation in the high‐performance blend of the donor polymer PM6 with the NFA Y6 is thoroughly investigated as a function of internal field, temperature and excitation energy. Results show that photocurrent generation is essentially barrierless with near‐unity efficiency, regardless of excitation energy. Efficient charge separation is maintained over a wide temperature range, down to 100 K, despite the small driving force for charge generation. Studies on a blend with a low concentration of the NFA, measurements of the energetic disorder, and theoretical modeling suggest that CT state dissociation is assisted by the electrostatic interfacial field which for Y6 is large enough to compensate the Coulomb dissociation barrier.