Titelangaben
Heun, S. ; Mahrt, R. F. ; Greiner, Andreas ; Lemmer, Ulrich ; Bässler, Heinz ; Halliday, D. A. ; Bradley, D. D. C. ; Burn, P. L. ; Holmes, Andrew B.:
Conformational effects in poly(p-phenylene vinylene)s revealed by low-temperature site-selective fluorescence.
In: Journal of Physics: Condensed Matter.
Bd. 5
(1993)
Heft 2
.
- S. 247-260.
ISSN 1361-648X
DOI: https://doi.org/10.1088/0953-8984/5/2/012
Abstract
Low-temperature site-selective fluorescence (SSF) Spectroscopy is employed to study morphological effects on the conformation of poly(p-phenylene vinylene) (PPV) and its phenyl-substituted, soluble derivative poly(phenylphenylenevinylene) (PPPV). Samples of PPV prepared as spin-coated thin films and stretch-aligned free-standing films, and samples of PPPV prepared as cast films and as blends with poly(methylmethacrylate) and polycarbonate have been studied. The results that we present are consistent with the notion that each polymer sample consists of an army of ordered chain segments whose average length reflects the perfection of the local structure. The statistical distribution of the segment lengths is responsible for inhomogeneous broadening of the optical spectra (absorption and emission). The dominant electronic excitation created by photoexcitation across the pi-pi* energy gap is a singlet exciton that can execute a random walk among the chain segments. SSF spectroscopy allows us to distinguish the contributions to the apparent fluorescence Stokes shift that arise from energy relaxation through excitation migration (spectral diffusion) and from structural relaxation of the polymer chain (self-localization). The structural contribution to the Stokes shift approaches zero in well aligned PPV and reaches values of up to 500 cm-1 in highly disordered PPPV films. The SSP method also provides a means of assessing the extent of phase separation that occurs in PPPV blends.
Weitere Angaben
Publikationsform: | Artikel in einer Zeitschrift |
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Begutachteter Beitrag: | Ja |
Zusätzliche Informationen: | ISI:A1993KH87300012 |
Keywords: | CONJUGATED POLYMERS; VIBRATIONAL-SPECTRA; SINGLE-CRYSTALS; SPECTROSCOPY; MODEL; ABSORPTION; EXCITON; LIGHT; PPV |
Institutionen der Universität: | Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Chemie > Lehrstuhl Makromolekulare Chemie II > Lehrstuhl Makromolekulare Chemie II - Univ.-Prof. Dr. Andreas Greiner Fakultäten Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Chemie Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Chemie > Lehrstuhl Makromolekulare Chemie II |
Titel an der UBT entstanden: | Nein |
Themengebiete aus DDC: | 500 Naturwissenschaften und Mathematik > 540 Chemie |
Eingestellt am: | 16 Apr 2015 10:39 |
Letzte Änderung: | 12 Jul 2022 11:36 |
URI: | https://eref.uni-bayreuth.de/id/eprint/10320 |