title: Chain-Length-Dependent Exciton Dynamics in Linear Oligothiophenes Probed Using Ensemble and Single-Molecule Spectroscopy.
abstract: Exciton dynamics in π-conjugated molecular systems is highly susceptible to conformational disorder. Using time-resolved and single-molecule spectroscopic techniques, the effect of chain length on the exciton dynamics in a series of linear oligothiophenes, for which the conformational disorder increased with increasing chain length, was investigated. As a result, extraordinary features of the exciton dynamics in longer-chain oligothiophene were revealed. Ultrafast fluorescence depolarization processes were observed due to exciton self-trapping in longer and bent chains. Increase in exciton delocalization during dynamic planarization processes was also observed in the linear oligothiophenes via time-resolved fluorescence spectra but was restricted in L-10T because of its considerable conformational disorder. Exciton delocalization was also unexpectedly observed in a bent chain using single-molecule fluorescence spectroscopy. Such delocalization modulates the fluorescence spectral shape by attenuating the 0-0 peak intensity. Collectively, these results provide significant insights into the exciton dynamics in conjugated polymers.
authors.affiliation: Spectroscopy Laboratory for Functional π-Electronic Systems and Department of Chemistry, Yonsei University , Seoul 03722, Korea.
authors.forename: Tae-Woo
authors.initials: TW
authors.lastname: Kim
authors.affiliation: Spectroscopy Laboratory for Functional π-Electronic Systems and Department of Chemistry, Yonsei University , Seoul 03722, Korea.
authors.forename: Woojae
authors.initials: W
authors.lastname: Kim
authors.affiliation: Spectroscopy Laboratory for Functional π-Electronic Systems and Department of Chemistry, Yonsei University , Seoul 03722, Korea.
authors.forename: Kyu Hyung
authors.initials: KH
authors.lastname: Park
authors.affiliation: Spectroscopy Laboratory for Functional π-Electronic Systems and Department of Chemistry, Yonsei University , Seoul 03722, Korea.
authors.forename: Pyosang
authors.initials: P
authors.lastname: Kim
authors.affiliation: Spectroscopy Laboratory for Functional π-Electronic Systems and Department of Chemistry, Yonsei University , Seoul 03722, Korea.
authors.forename: Jae-Won
authors.initials: JW
authors.lastname: Cho
authors.affiliation: Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University , Hachioji, Tokyo 192-0397, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Shimizu
authors.affiliation: Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University , Hachioji, Tokyo 192-0397, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Iyoda
authors.affiliation: Spectroscopy Laboratory for Functional π-Electronic Systems and Department of Chemistry, Yonsei University , Seoul 03722, Korea.
authors.forename: Dongho
authors.initials: D
authors.lastname: Kim