Nonfullerene Acceptors Bearing Spiro-Substituted Bithiophene Units in Organic Solar Cells: Tuning the Frontier Molecular Orbital Distribution to Reduce Exciton Binding Energy.

Autor: Wang K; The Institute of Scientific and Industrial Research (SANKEN), Osaka University 8-1 Mihogaoka, Ibaraki, Osaka, 567-0047, Japan., Jinnai S; The Institute of Scientific and Industrial Research (SANKEN), Osaka University 8-1 Mihogaoka, Ibaraki, Osaka, 567-0047, Japan.; Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives (ICS-OTRI), Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan., Urakami T; Department of Molecular Engineering, Graduate School of Engineering, Kyoto University Nishikyo-ku, Kyoto, 615-8510, Japan., Sato H; Department of Molecular Engineering, Graduate School of Engineering, Kyoto University Nishikyo-ku, Kyoto, 615-8510, Japan.; Fukui Institute for Fundamental Chemistry, Kyoto University, Takano Nishihirakicho 34-4, Sakyo-ku, Kyoto, 606-8103, Japan., Higashi M; Department of Complex Systems Science, Graduate School of Informatics, Nagoya University Furo-cho, Chikusa-ku, Nago-ya, 464-8601, Japan., Tsujimura S; Department of Chemistry, Graduate school of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo, 657-8501, Japan., Kobori Y; Molecular Photoscience Research Center, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo, 657-8501, Japan., Adachi R; Graduate School of Natural Science & Technology, Okayama University, 3-1-1 Tsushima-naka, Okayama, 700-8530, Japan., Yamakata A; Graduate School of Natural Science & Technology, Okayama University, 3-1-1 Tsushima-naka, Okayama, 700-8530, Japan., Ie Y; The Institute of Scientific and Industrial Research (SANKEN), Osaka University 8-1 Mihogaoka, Ibaraki, Osaka, 567-0047, Japan.; Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives (ICS-OTRI), Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.
Jazyk: angličtina
Zdroj: Angewandte Chemie (International ed. in English) [Angew Chem Int Ed Engl] 2024 Nov 18; Vol. 63 (47), pp. e202412691. Date of Electronic Publication: 2024 Oct 15.
DOI: 10.1002/anie.202412691
Abstrakt: The development of nonfullerene acceptors (NFAs), represented by ITIC, has contributed to improving the power conversion efficiency (PCE) of organic solar cells (OSCs). Although tuning the electronic structures to reduce the exciton binding energy (E b ) is considered to promote photocharge generation, a rational molecular design for NFAs has not been established. In this study, we designed and developed two ITIC-based NFAs bearing spiro-substituted bithiophene or biphenyl units (named SpiroT-DCI and SpiroF-DCI) to tune the frontier molecular orbital (FMO) distribution of NFAs. While the highest occupied molecular orbitals (HOMOs) of SpiroF-DCI and ITIC are delocalized in the main π-conjugated framework, the HOMO of SpiroT-DCI is distributed on the bithiophene unit. Reflecting this difference, SpiroT-DCI exhibits a smaller E b than either SpiroF-DCI or ITIC, and exhibits greater external quantum efficiency in single-component OSCs. Furthermore, SpiroT-DCI shows improved PCEs for bulk-heterojunction OSCs with a donor of PBDB-T, compared with that of either SpiroT-DCI or ITIC. Time-resolved spectroscopy measurements show that the photo-induced intermolecular charge separation is effective even in pristine SpiroT-DCI films. This study highlights the introduction of spiro-substituted bithiophene units that are effective in tuning the FMOs of ITIC, which is desirable for reducing the E b and improving the PCE in OSCs.
(© 2024 The Author(s). Angewandte Chemie International Edition published by Wiley-VCH GmbH.)
Databáze: MEDLINE
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