Mode-Specific Vibrational Analysis of Exciton Delocalization and Structural Dynamics in Conjugated Oligomers

Woojae Kim; Shinya Tahara; Hikaru Kuramochi; Satoshi Takeuchi; Taeyeon Kim; Tahei Tahara; Dongho Kim

doi:10.1002/anie.202102168

Mode-Specific Vibrational Analysis of Exciton Delocalization and Structural Dynamics in Conjugated Oligomers

Woojae Kim, Shinya Tahara, Hikaru Kuramochi, Satoshi Takeuchi, Taeyeon Kim, Tahei Tahara, Dongho Kim

Department of Chemistry

Research output: Contribution to journal › Article › peer-review

Abstract

Exciton delocalization in organic semiconducting polymers, affected by structures at a molecular level, plays a crucial role in modulating relaxation pathways, such as charge generation and singlet fission, which can boost device efficiency. However, the structural diversity of polymers and broad signals from typical electronic spectroscopy have their limits when it comes to revealing the interplay between local structures and exciton delocalization. To tackle these problems, we apply femtosecond stimulated Raman spectroscopy in archetypical conjugated oligothiophenes with different chain lengths. We observed Raman frequency dispersions of symmetric bond stretching modes and mode-specific kinetics in the S₁ Raman spectra, which underpins the subtle and complex interplay between exciton delocalization and bond length alternation along the conjugation coordinate. Our results provide a more general picture of exciton delocalization in the context of molecular structures for conjugated materials.

Original language	English
Pages (from-to)	16999-17008
Number of pages	10
Journal	Angewandte Chemie - International Edition
Volume	60
Issue number	31
DOIs	https://doi.org/10.1002/anie.202102168
Publication status	Published - 2021 Jul 26

Bibliographical note

Funding Information:
We thank Prof. Masahiko Iyoda at Tokyo Metropolitan University for providing us with a series of L-nTs investigated in this study. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT; No. 2020R1A5A1019141). The quantum chemical calculations were supported by the National Institute of Supercomputing and Network (NISN)/Korea Institute of Science and Technology Information (KISTI) with supercomputing resources including technical support (TS-2020-RE-004). W.K. acknowledges financial support from the NRF Grant funded by the Korean Government (NRF-2015H1A2A1033685-Global Ph.D. Fellowship Program).

Funding Information:
We thank Prof. Masahiko Iyoda at Tokyo Metropolitan University for providing us with a series of s investigated in this study. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT; No. 2020R1A5A1019141). The quantum chemical calculations were supported by the National Institute of Supercomputing and Network (NISN)/Korea Institute of Science and Technology Information (KISTI) with supercomputing resources including technical support (TS‐2020‐RE‐004). W.K. acknowledges financial support from the NRF Grant funded by the Korean Government (NRF‐2015H1A2A1033685‐Global Ph.D. Fellowship Program). L‐T n

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© 2021 Wiley-VCH GmbH

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Catalysis
Chemistry(all)

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@article{45da43242e134a158a4757468d94b375,

title = "Mode-Specific Vibrational Analysis of Exciton Delocalization and Structural Dynamics in Conjugated Oligomers",

abstract = "Exciton delocalization in organic semiconducting polymers, affected by structures at a molecular level, plays a crucial role in modulating relaxation pathways, such as charge generation and singlet fission, which can boost device efficiency. However, the structural diversity of polymers and broad signals from typical electronic spectroscopy have their limits when it comes to revealing the interplay between local structures and exciton delocalization. To tackle these problems, we apply femtosecond stimulated Raman spectroscopy in archetypical conjugated oligothiophenes with different chain lengths. We observed Raman frequency dispersions of symmetric bond stretching modes and mode-specific kinetics in the S1 Raman spectra, which underpins the subtle and complex interplay between exciton delocalization and bond length alternation along the conjugation coordinate. Our results provide a more general picture of exciton delocalization in the context of molecular structures for conjugated materials.",

author = "Woojae Kim and Shinya Tahara and Hikaru Kuramochi and Satoshi Takeuchi and Taeyeon Kim and Tahei Tahara and Dongho Kim",

note = "Funding Information: We thank Prof. Masahiko Iyoda at Tokyo Metropolitan University for providing us with a series of L-nTs investigated in this study. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT; No. 2020R1A5A1019141). The quantum chemical calculations were supported by the National Institute of Supercomputing and Network (NISN)/Korea Institute of Science and Technology Information (KISTI) with supercomputing resources including technical support (TS-2020-RE-004). W.K. acknowledges financial support from the NRF Grant funded by the Korean Government (NRF-2015H1A2A1033685-Global Ph.D. Fellowship Program). Funding Information: We thank Prof. Masahiko Iyoda at Tokyo Metropolitan University for providing us with a series of s investigated in this study. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT; No. 2020R1A5A1019141). The quantum chemical calculations were supported by the National Institute of Supercomputing and Network (NISN)/Korea Institute of Science and Technology Information (KISTI) with supercomputing resources including technical support (TS‐2020‐RE‐004). W.K. acknowledges financial support from the NRF Grant funded by the Korean Government (NRF‐2015H1A2A1033685‐Global Ph.D. Fellowship Program). L‐T n Publisher Copyright: {\textcopyright} 2021 Wiley-VCH GmbH",

year = "2021",

month = jul,

day = "26",

doi = "10.1002/anie.202102168",

language = "English",

volume = "60",

pages = "16999--17008",

journal = "Angewandte Chemie - International Edition",

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AU - Kim, Woojae

AU - Tahara, Shinya

AU - Kuramochi, Hikaru

AU - Takeuchi, Satoshi

AU - Kim, Taeyeon

AU - Tahara, Tahei

AU - Kim, Dongho

N1 - Funding Information: We thank Prof. Masahiko Iyoda at Tokyo Metropolitan University for providing us with a series of L-nTs investigated in this study. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT; No. 2020R1A5A1019141). The quantum chemical calculations were supported by the National Institute of Supercomputing and Network (NISN)/Korea Institute of Science and Technology Information (KISTI) with supercomputing resources including technical support (TS-2020-RE-004). W.K. acknowledges financial support from the NRF Grant funded by the Korean Government (NRF-2015H1A2A1033685-Global Ph.D. Fellowship Program). Funding Information: We thank Prof. Masahiko Iyoda at Tokyo Metropolitan University for providing us with a series of s investigated in this study. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT; No. 2020R1A5A1019141). The quantum chemical calculations were supported by the National Institute of Supercomputing and Network (NISN)/Korea Institute of Science and Technology Information (KISTI) with supercomputing resources including technical support (TS‐2020‐RE‐004). W.K. acknowledges financial support from the NRF Grant funded by the Korean Government (NRF‐2015H1A2A1033685‐Global Ph.D. Fellowship Program). L‐T n Publisher Copyright: © 2021 Wiley-VCH GmbH

PY - 2021/7/26

Y1 - 2021/7/26

N2 - Exciton delocalization in organic semiconducting polymers, affected by structures at a molecular level, plays a crucial role in modulating relaxation pathways, such as charge generation and singlet fission, which can boost device efficiency. However, the structural diversity of polymers and broad signals from typical electronic spectroscopy have their limits when it comes to revealing the interplay between local structures and exciton delocalization. To tackle these problems, we apply femtosecond stimulated Raman spectroscopy in archetypical conjugated oligothiophenes with different chain lengths. We observed Raman frequency dispersions of symmetric bond stretching modes and mode-specific kinetics in the S1 Raman spectra, which underpins the subtle and complex interplay between exciton delocalization and bond length alternation along the conjugation coordinate. Our results provide a more general picture of exciton delocalization in the context of molecular structures for conjugated materials.

AB - Exciton delocalization in organic semiconducting polymers, affected by structures at a molecular level, plays a crucial role in modulating relaxation pathways, such as charge generation and singlet fission, which can boost device efficiency. However, the structural diversity of polymers and broad signals from typical electronic spectroscopy have their limits when it comes to revealing the interplay between local structures and exciton delocalization. To tackle these problems, we apply femtosecond stimulated Raman spectroscopy in archetypical conjugated oligothiophenes with different chain lengths. We observed Raman frequency dispersions of symmetric bond stretching modes and mode-specific kinetics in the S1 Raman spectra, which underpins the subtle and complex interplay between exciton delocalization and bond length alternation along the conjugation coordinate. Our results provide a more general picture of exciton delocalization in the context of molecular structures for conjugated materials.

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ER -

Mode-Specific Vibrational Analysis of Exciton Delocalization and Structural Dynamics in Conjugated Oligomers

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