Relationship between Dynamic Planarization Processes and Exciton Delocalization in Cyclic Oligothiophenes.
In cyclic molecular structures, while the effect of conformational disorder on exciton delocalization is well understood, the impact of dynamic planarization processes remains unclear due to a lack of detailed investigation on the associated exciton dynamics. Thus, we have investigated the exciton delocalization of π-conjugated linear and cyclic oligothiophenes in the course of dynamic planarization processes by time-resolved fluorescence spectra measurements and theoretical calculations. Especially, through a comparative analysis of linear and cyclic oligothiophenes, we found that the evolution of 0-0 and 0-1 vibronic bands is strongly related to the conformations of cyclic molecular systems, reflecting the extent of exciton delocalization. Collectively, we believe that our findings are applicable to various π-conjugated organic materials and will provide new insights into the relationship between exciton delocalization and cyclic molecular conformation.
†Spectroscopy Laboratory for Functional π-Electronic Systems and Department of Chemistry, Yonsei University, Seoul 120-749, Korea.
Pyosang
P
Kim
†Spectroscopy Laboratory for Functional π-Electronic Systems and Department of Chemistry, Yonsei University, Seoul 120-749, Korea.
Kyu Hyung
KH
Park
†Spectroscopy Laboratory for Functional π-Electronic Systems and Department of Chemistry, Yonsei University, Seoul 120-749, Korea.
Woojae
W
Kim
‡Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan.
Tomoya
T
Tamachi
‡Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan.
Masahiko
M
Iyoda
†Spectroscopy Laboratory for Functional π-Electronic Systems and Department of Chemistry, Yonsei University, Seoul 120-749, Korea.
Dongho
D
Kim
bond length alternation; conformational heterogeneities; fluorescence up-conversion; linear and cyclic molecular structure; time-resolved fluorescence spectra; vibronic band