Biphasic Self-Assembly Pathways and Size-Dependent Photophysical Properties of Perylene Bisimide Dye Aggregates
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- 作者：Franziska Fennel ; Steffen Wolter ; Zengqi Xie ; Per-Arno Pl枚tz ; Oliver K眉hn ; Frank W眉rthner ; Stefan Lochbrunner
- 刊名：Journal of the American Chemical Society
- 出版年：2013
- 出版时间：December 18, 2013
- 年：2013
- 卷：135
- 期：50
- 页码：18722-18725
- 全文大小：300K
- 年卷期：v.135,no.50(December 18, 2013)
- ISSN：1520-5126
文摘
The concentration-dependent absorption and temperature-dependent fluorescence of the perylene bisimide dye PBI聽1 in methylcyclohexane point to a biphasic aggregation behavior. At intermediate concentrations and temperatures, respectively, a dimer with low fluorescence yield dominates, which cannot be extended to longer aggregates. Those are formed at high concentrations and low temperatures, respectively, via a second, energetically unfavorable dimer species that acts as a nucleus. A corresponding aggregation model reproduces accurately the concentration dependence and allows extracting the equilibrium constants and spectra of the distinct species. The differences in the photophysical properties indicate H-type excitonic coupling for the favored dimer and J-type characteristics for the extended aggregates which could be related to structural models based on DFT calculations. The energetics can be understood by considering hydrogen-bonding and 蟺鈥撓€-stacking interactions.