Origin of Simultaneous Donor-Acceptor Emission in Single Molecules of Peryleneimide-Terrylenediimide Labeled Polyphenylene Dendrimers

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• 作者：Sergey M. Melnikov ; Edwin K. L. Yeow ; Hiroshi Uji-i ; Mircea Cotlet ; Klaus M&uuml ; llen ; Frans C. De Schryver ; J&ouml ; rg Enderlein ; Johan Hofkens
• 刊名：Journal of Physical Chemistry B
• 出版年：2007
• 出版时间：February 1, 2007
• 年：2007
• 卷：111
• 期：4
• 页码：708 - 719
• 全文大小：578K
• 年卷期：v.111,no.4(February 1, 2007)
• ISSN：1520-5207

文摘

Förster type resonance energy transfer (FRET) in donor-acceptor peryleneimide-terrylenediimide dendrimershas been examined at the single molecule level. Very efficient energy transfer between the donor and theacceptor prevent the detection of donor emission before photobleaching of the acceptor. Indeed, in solution,on exciting the donor, only acceptor emission is detected. However, at the single molecule level, an importantfraction of the investigated individual molecules (about 10-15%) show simultaneous emission from bothdonor and acceptor chromophores. The effect becomes apparent mostly after photobleaching of the majorityof donors. Single molecule photon flux correlation measurements in combination with computer simulationsand a variety of excitation conditions were used to determine the contribution of an exciton blockade to thistwo-color emission. Two-color defocused wide-field imaging showed that the two-color emission goes handin hand with an unfavorable orientation between one of the donors and the acceptor chromophore.