Conformational Disorder and Ultrafast Exciton Relaxation in PPV-family Conjugated Polymers

被引:142
作者
Dykstra, Tieneke E. [1 ,2 ]
Hennebicq, Emmanuelle [3 ]
Beljonne, David [3 ]
Gierschner, Johannes [3 ,4 ]
Claudio, Gil [5 ]
Bittner, Eric R. [6 ,7 ]
Knoester, Jasper [8 ,9 ]
Scholes, Gregory D. [1 ,2 ]
机构
[1] Univ Toronto, Inst Opt Sci, Lash Miller Chem Labs, Toronto, ON M5S 3H6, Canada
[2] Univ Toronto, Ctr Quantum Informat & Quantum Control, Toronto, ON M5S 3H6, Canada
[3] Univ Mons, Ctr Res Mol Elect & Photon, Lab Chem Novel Mat, B-7000 Mons, Belgium
[4] UAM, Madrid Inst Adv Studies, IMDEA Nanosci, E-28049 Madrid, Spain
[5] Max Planck Inst Polymer Res, D-55021 Mainz, Germany
[6] Univ Houston, Dept Chem, Houston, TX 77204 USA
[7] Univ Houston, Ctr Mat Chem, Houston, TX 77204 USA
[8] Univ Groningen, Inst Theoret Phys, NL-9747 AG Groningen, Netherlands
[9] Univ Groningen, Zernike Inst Adv Mat, NL-9747 AG Groningen, Netherlands
基金
美国国家科学基金会;
关键词
SITE-SELECTIVE FLUORESCENCE; ENERGY-TRANSFER; MEH-PPV; POLY(P-PHENYLENE VINYLENE); POLY(PARA-PHENYLENE VINYLENE); TEMPERATURE-DEPENDENCE; INTERMEDIATE NEGLECT; EXCITATION TRANSFER; ABSORPTION-SPECTRA; CONDENSED PHASES;
D O I
10.1021/jp807249b
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
We report combined experimental and theoretical studies of excitation relaxation in poly[2-methoxy,5-(2'ethyl-hexoxy)-1,4-phenylenevinylene] (MEH-PPV), oligophenylenevinylene (OPV) molecules of varying length, and model PPV chains. We build on the paradigm that the basic characteristics of conjugated polymers are decided by conformational subunits defined by conjugation breaks caused by torsional disorder along the chain. The calculations reported here indicate that for conjugated polymers like those in the PPV family, these conformational subunits electronically couple to neighboring subunits, forming subtly delocalized collective states of nanoscale excitons that determine the polymer optical properties. We find that relaxation among these exciton states can lead to a decay of anisotropy on ultrafast time scales. Unlike in Forster energy transfer, the exciton does not necessarily translate over a large distance. Nonetheless, the disorder in the polymer chain means that even small changes in the exciton size or location has a significant effect on the relaxation pathway and therefore the anisotropy decay.
引用
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页码:656 / 667
页数:12
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