標題: Relaxation dynamics of 2,7-and 3,6-distyrylcarbazoles in solutions and in solid films: Mechanism for efficient nonradiative deactivation in the 3,6-linked carbazole
作者: Wang, TT
Chung, SM
Wu, FI
Shu, CF
Diau, EWG
應用化學系分子科學碩博班
Institute of Molecular science
公開日期: 22-Dec-2005
摘要: We performed time-resolved spectral investigations of two distyrylcarbazole derivatives, 2,7- and 3,6-distyrylcarbazole (2,7-DPVTCz and 3,6-DPVTCz, respectively), in dilute toluene solution and in solid films mixed with poly(methyl methacrylate) (PMMA). The lifetime of 2,7-DPVTCz in its excited state in solution is similar to 100 times as great as that of 3,6-DPVTCz, consistent with their photophysical nature. The former shows intense emission, but the latter is nearly nonfluorescent in a free environment. Moreover, the lifetime of 3,6-DPVTCz in its excited state increased also similar to 100 times when the molecule was encapsulated in a 3,6-DPVTCz/PMMA solid film, indicating that intramolecular motion of the molecule significantly affects the observed relaxation dynamics in a confined environment. Calculations on the excited states indicate that ail efficient intersystern crossing is activated upon twisting of the bridged C-C single bond in a free 3,6-linked carbazole; such efficient deactivation is impractical in 2,7-linked carbazole or for 3,6-linked carbazole in a PMMA matrix. Information obtained from experiments on femtosecond fluorescence enables LIS to distinguish crucial relaxation processes in the excited state for a profound understanding of the details of vibrational and electronic relaxations of 3,6-DPVTCz in Solution.
URI: http://dx.doi.org/10.1021/jp053940k
http://hdl.handle.net/11536/12953
ISSN: 1520-6106
DOI: 10.1021/jp053940k
期刊: JOURNAL OF PHYSICAL CHEMISTRY B
Volume: 109
Issue: 50
起始頁: 23827
結束頁: 23835
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