title: Origin of simultaneous donor-acceptor emission in single molecules of peryleneimide-terrylenediimide labeled polyphenylene dendrimers.
abstract: Förster type resonance energy transfer (FRET) in donor-acceptor peryleneimide-terrylenediimide dendrimers has been examined at the single molecule level. Very efficient energy transfer between the donor and the acceptor 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 important fraction of the investigated individual molecules (about 10-15%) show simultaneous emission from both donor and acceptor chromophores. The effect becomes apparent mostly after photobleaching of the majority of donors. Single molecule photon flux correlation measurements in combination with computer simulations and a variety of excitation conditions were used to determine the contribution of an exciton blockade to this two-color emission. Two-color defocused wide-field imaging showed that the two-color emission goes hand in hand with an unfavorable orientation between one of the donors and the acceptor chromophore.
authors.affiliation: Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200 F, 3001 Heverlee, Belgium.
authors.forename: Sergey M
authors.initials: SM
authors.lastname: Melnikov
authors.forename: Edwin K L
authors.initials: EK
authors.lastname: Yeow
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Uji-i
authors.forename: Mircea
authors.initials: M
authors.lastname: Cotlet
authors.forename: Klaus
authors.initials: K
authors.lastname: Müllen
authors.forename: Frans C
authors.initials: FC
authors.lastname: De Schryver
authors.forename: Jörg
authors.initials: J
authors.lastname: Enderlein
authors.forename: Johan
authors.initials: J
authors.lastname: Hofkens
mesh_terms: D001703:Biophysics / Q000379:methods; D002627:Chemistry, Physical / Q000379:methods; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods; D007091:Image Processing, Computer-Assisted; D007094:Imides / Q000737:chemistry*; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence / Q000379:methods; D008956:Models, Chemical; D015233:Models, Statistical; D009010:Monte Carlo Method; D010569:Perylene / Q000031:analogs & derivatives* / Q000737:chemistry; D017785:Photons; D011108:Polymers / Q000737:chemistry*; D011336:Probability; D013997:Time Factors
chemical_list: D007094:Imides; D011108:Polymers; C520054:peryleneimide-terrylenediimide; D010569:Perylene; C041325:polyphenylene sulfide