Conformational effect on energy transfer in single polythiophene chains.
Herein we describe the use of regioregular (rr-) and regiorandom (rra-) P3HT as models to study energy transfer in ordered and disordered single conjugated polymer chains. Single molecule fluorescence spectra and excitation/emission polarization measurements were compared with a Förster resonance energy transfer (FRET) model simulation. An increase in the mean single chain polarization anisotropy from excitation to emission was observed for both rr- and rra-P3HT. The peak emission wavelengths of rr-P3HT were at substantially lower energies than those of rra-P3HT. A simulation based on FRET in single polymer chain conformations successfully reproduced the experimental observations. These studies showed that ordered conformations facilitated efficient energy transfer to a small number of low-energy sites compared to disordered conformations. As a result, the histograms of spectral peak wavelengths for ordered conformations were centered at much lower energies than those obtained for disordered conformations. Collectively, these experimental and simulated results provide the basis for quantitatively describing energy transfer in an important class of conjugated polymers commonly used in a variety of organic electronics applications.
Center for Nano and Molecular Science and Technology, Department of Chemistry and Biochemistry, University of Texas, Austin, Texas 78712, United States.
Takuji
T
Adachi
Girish
G
Lakhwani
Matthew C
MC
Traub
Robert J
RJ
Ono
Christopher W
CW
Bielawski
Paul F
PF
Barbara
David A
DA
Vanden Bout
D004735:Energy Transfer; D031541:Fluorescence Resonance Energy Transfer; D008958:Models, Molecular; D008968:Molecular Conformation; D011108:Polymers / Q000737:chemistry*; D013876:Thiophenes / Q000737:chemistry*
D011108:Polymers; D013876:Thiophenes; C066730:polythiophene