Intramolecular Interactions of Highly 蟺-Conjugated Perylenediimide Oligomers Probed by Single-Molecule Spectroscopy
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- 作者：Jae-Won Cho ; Hyejin Yoo ; Ji-Eun Lee ; Qifan Yan ; Dahui Zhao ; Dongho Kim
- 刊名：The Journal of Physical Chemistry Letters
- 出版年：2014
- 出版时间：November 6, 2014
- 年：2014
- 卷：5
- 期：21
- 页码：3895-3901
- 全文大小：434K
- ISSN：1948-7185
文摘
Highly 蟺-conjugated perylenediimide (PDI) oligomers are promising low band gap organic materials for various applications in optoelectronics. In this work, individual fluorescence dynamics of ethynylene- and butadiynylene-bridged dimeric and trimeric PDIs (PEP, PBP, and PEPEP) were monitored and analyzed by single-molecule fluorescence spectroscopy to gain information on the degree of extension of 蟺-conjugation through the acetylene bridge in PDI multichromophores. The simultaneous measurements of fluorescence intensity, lifetime, and spectrum indicate a sequential decrease in 蟺-conjugation upon photobleaching of PDI monomer units. Furthermore, Huang鈥揜hys (HR) factors, S, are obtained to evaluate the degree of electronic coupling in view of 蟺-conjugation and overall rigidity between the PDI units in PDI oligomers at the single-molecule level. In addition, butadiynylene-bridged dimeric PDI (PBP) reveals conformational heterogeneity due to the long butadiynylene linker. These results suggest a new way to control the photophysical properties of the PDI multichromophoric system by expansion of 蟺-conjugation and modification with different linker groups.