Ultrafast Symmetry-Breaking Charge Separation in a Perylene Bisimide Dimer Enabled by Vibronic Coupling and Breakdown of Adiabaticity

Yongseok Hong, Felix Schlosser, Woojae Kim, Frank Würthner, Dongho Kim

Research output: Contribution to journalArticlepeer-review

Abstract

Perylene bisimides (PBIs) have received great attention in their applicability to optoelectronics. Especially, symmetry-breaking charge separation (SB-CS) in PBIs has been investigated to mimic the efficient light capturing and charge generation in natural light-harvesting systems. However, unlike ultrafast CS dynamics in donor-acceptor heterojunction materials, ultrafast SB-CS in a stacked homodimer has still been challenging due to excimer formation in the absence of rigidifying surroundings such as a special pair in the natural systems. Herein, we present the detailed mechanism of ultrafast photoinduced SB-CS occurring in a 1,7-bis(N-pyrrolidinyl) PBI dimer within a cyclophane. Through narrow-band and broad-band transient absorption spectroscopy, we demonstrate that ultrafast SB-CS in the dimer is enabled by the combination of (1) vibrationally coherent charge-transfer resonance-enhanced excimer formation and (2) breakdown of adiabaticity (formation of SB-CS diabats) in the excimer state via structural and solvent fluctuation. Quantum chemical calculations also underpin that the participation of strong electron-donating substituents in overall vibrational modes plays a crucial role in triggering the ultrafast SB-CS. Therefore, our work provides an alternative route to facilitate ultrafast SB-CS in PBIs and thereby establishes a novel strategy for the design of optoelectronic materials.

Original languageEnglish
Pages (from-to)15539-15548
Number of pages10
JournalJournal of the American Chemical Society
Volume144
Issue number34
DOIs
Publication statusPublished - 2022 Aug 31

Bibliographical note

Funding Information:
This work was supported by the National Research Foundation of Korea (NRF) through a grant funded by the South Korean government (MEST) (No. 2021R1A2C300630811) and by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (No. 2020R1A5A1019141). The quantum mechanical calculations were supported by the National Institute of Supercomputing and Network (NISN)/Korea Institute of Science and Technology Information (KISTI) with needed supercomputing resources, including technical support (KSC-2021-CRE-0473). This work has been supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) within the research unit FOR 1809 and the research program Solar Technology Go Hybrid of the Bavarian Ministry of Science and the Arts.

Publisher Copyright:
© 2022 American Chemical Society.

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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