Revealing competitive Forster-type resonance energy-transfer pathways in single bichromophoric molecules.
We demonstrate measurements of the efficiency of competing Förster-type energy-transfer pathways in single bichromophoric systems by monitoring simultaneously the fluorescence intensity, fluorescence lifetime, and the number of independent emitters with time. Peryleneimide end-capped fluorene trimers, hexamers, and polymers with interchromophore distances of 3.4, 5.9, and on average 42 nm, respectively, served as bichromophoric systems. Because of different energy-transfer efficiencies, variations in the interchromophore distance enable the switching between homo-energy transfer (energy hopping), singlet-singlet annihilation, and singlet-triplet annihilation. The data suggest that similar energy-transfer pathways have to be considered in the analysis of single-molecule trajectories of donor/acceptor pairs as well as in natural and synthetic multichromophoric systems such as light-harvesting antennas, oligomeric fluorescent proteins, and dendrimers. Here we report selectively visualization of different energy-transfer pathways taking place between identical fluorophores in individual bichromophoric molecules.
Laboratory for Photochemistry and Spectroscopy, Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200 F, 3001 Heverlee, Belgium. johan.hofkens@chem.kuleuven.ac.be
Johan
J
Hofkens
Mircea
M
Cotlet
Tom
T
Vosch
Philip
P
Tinnefeld
Kenneth D
KD
Weston
Christophe
C
Ego
Andrew
A
Grimsdale
Klaus
K
Müllen
David
D
Beljonne
Jean Luc
JL
Brédas
Sven
S
Jordens
Gerd
G
Schweitzer
Markus
M
Sauer
Frans
F
De Schryver
D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D008956:Models, Chemical; D010569:Perylene / Q000737:chemistry; D055585:Physical Phenomena; D010825:Physics; D011108:Polymers / Q000737:chemistry; D013050:Spectrometry, Fluorescence / Q000379:methods*; D013997:Time Factors
D011108:Polymers; D010569:Perylene