Balanced Partnership between Donor and Acceptor Components in Nonfullerene Organic Solar Cells with >12% Efficiency |
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| Authors: | Yuze Lin Fuwen Zhao Shyamal K K Prasad Jing‐De Chen Wanzhu Cai Qianqian Zhang Kai Chen Yang Wu Wei Ma Feng Gao Jian‐Xin Tang Chunru Wang Wei You Justin M Hodgkiss Xiaowei Zhan |
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| Affiliation: | 1. Department of Materials Science and Engineering, College of Engineering, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Peking University, Beijing, China;2. Institute of Chemistry, Chinese Academy of Sciences, Beijing, China;3. MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand;4. Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, Suzhou, China;5. Biomolecular and Organic Electronics, IFM, Link?ping University, Link?ping, Sweden;6. Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA;7. State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, China |
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| Abstract: | Relative to electron donors for bulk heterojunction organic solar cells (OSCs), electron acceptors that absorb strongly in the visible and even near‐infrared region are less well developed, which hinders the further development of OSCs. Fullerenes as traditional electron acceptors have relatively weak visible absorption and limited electronic tunability, which constrains the optical and electronic properties required of the donor. Here, high‐performance fullerene‐free OSCs based on a combination of a medium‐bandgap polymer donor (FTAZ) and a narrow‐bandgap nonfullerene acceptor (IDIC), which exhibit complementary absorption, matched energy levels, and blend with pure phases on the exciton diffusion length scale, are reported. The single‐junction OSCs based on the FTAZ:IDIC blend exhibit power conversion efficiencies up to 12.5% with a certified value of 12.14%. Transient absorption spectroscopy reveals that exciting either the donor or the acceptor component efficiently generates mobile charges, which do not suffer from recombination to triplet states. Balancing photocurrent generation between the donor and nonfullerene acceptor removes undesirable constraints on the donor imposed by fullerene derivatives, opening a new avenue toward even higher efficiency for OSCs. |
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| Keywords: | fused ring electron acceptors nonfullerene solar cells organic solar cells photophysics |
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