Simplified Y6-Based Nonfullerene Acceptors: In-Depth Study on Molecular Structure–Property Relation, Molecular Dynamics Simulation, and Charge Dynamics

Dohun Yuk, Min Hun Jee, Chang Woo Koh, Won Woo Park, Hwa Sook Ryu, Dongchan Lee, Shinuk Cho, Shafket Rasool, Sungnam Park, Oh Hoon Kwon, Jin Young Kim, Han Young Woo

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)

Abstract

Two new Y6 derivatives of symmetrical YBO-2O and asymmetrical YBO-FO nonfullerene acceptors (NFAs) are prepared with a simplified synthetic procedure by incorporating octyl and fluorine substituents onto the terminal 2-(3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile (INCN) moiety. By moving the alkyl substituents on the Y6 core to the terminal INCN moiety, the lowest unoccupied molecular orbital of the YBO NFAs increases without decreasing solubility, resulting in high open-circuit voltages of the devices. Molecular dynamics simulation shows that YBO-2O/-FO preferentially form core–core and terminal–terminal dimeric interactions, demonstrating their tighter packing structure and higher electron mobility than Y6, which is consistent with 2D grazing incidence X-ray scattering and space charge limited current measurements. In blend films, the hole transfer (HT) from YBO-2O/-FO to the polymer donor PM6 is studied in detail by transient absorption spectroscopy, demonstrating efficient HT from YBO-FO to PM6 with their suitable energy level alignment. Despite the simplified synthesis, YBO-FO demonstrates photovoltaic performance similar to that of Y6, exhibiting a power conversion efficiency of 15.01%. Overall, this design strategy not only simplifies the synthetic procedures but also adjusts the electrical properties by modifying the intermolecular packing and energy level alignment, suggesting a novel simplified molecular design of Y6 derivatives.

Original languageEnglish
Article number2206547
JournalSmall
Volume19
Issue number10
DOIs
Publication statusPublished - 2023 Mar 8

Bibliographical note

Funding Information:
D.Y., M.H.J., C.W.K., and W.-W.P. contributed equally to this work. This work was supported by the National Research Foundation (NRF) of Korea (2019R1A2C2085290, 2020M3H4A3081814, 2019R1A6A1A11044070, 2019R1A6A1A11053838, 2022R1A4A1033247, and 2021R1A2C3008724). The authors appreciate Prof. Chang Seop Hong for thermogravimetric analysis. This work was also supported by the KU-KIST School Program.

Funding Information:
D.Y., M.H.J., C.W.K., and W.‐W.P. contributed equally to this work. This work was supported by the National Research Foundation (NRF) of Korea (2019R1A2C2085290, 2020M3H4A3081814, 2019R1A6A1A11044070, 2019R1A6A1A11053838, 2022R1A4A1033247, and 2021R1A2C3008724). The authors appreciate Prof. Chang Seop Hong for thermogravimetric analysis. This work was also supported by the KU‐KIST School Program.

Publisher Copyright:
© 2022 Wiley-VCH GmbH.

Keywords

  • alkyl chain engineering
  • energy loss
  • molecular dynamics
  • nonfullerene acceptors
  • organic solar cells
  • transient absorption spectroscopy

ASJC Scopus subject areas

  • Biotechnology
  • General Chemistry
  • Biomaterials
  • General Materials Science

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