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Proceedings Paper

Long-lived polarons and triplet excitons in ladder-type poly(p-phenylenes) and poly(p-phenylene ethynylenes)
Author(s): Jonathan Partee; Joseph Shinar; Wilhelm Graupner; Guenther Leising; Scott W. Jessen; Arthur J. Epstein; Yi Wei Ding; Thomas J. Barton
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Paper Abstract

Recent x-band optically detected magnetic resonance studies of spin 1/2 polaron and spin 1 triplet exciton dynamics in ladder-type poly(p-phenylene) and poly(p-phenylene ethynylene) (PPE) films and solutions are described. The results suggest that the polaron resonance is due to interchain polaron pairs with lifetimes 10 microsecond(s) <EQ (tau) <EQ 4 ms range. The absence of delayed fluorescence at such times as well as other observations lead to the conclusion that the mechanism responsible for this resonance is the nonradiative quenching of singlet excitons by the polarons, whose population decreases at the field-for- resonance. The full-field triplet pattern is 700 - 1200 G wide, consistent with a triplet localized on a phenylene ring. In frozen toluene solutions of PPE, the amplitudes (Delta) I/I of both the polaron and half-field triplet resonances decrease similarly with concentration, and increase similarly with laser power P as P(alpha ), where 1/3 <EQ (alpha) <EQ 1/2. Hence, the triplet resonance is believed to be due to triplet intrinsically trapped and stabilized at similar interchain sites. Possible scenarios which link the processes yielding the resonances are also discussed.

Paper Details

Date Published: 1 December 1997
PDF: 14 pages
Proc. SPIE 3145, Optical Probes of Conjugated Polymers, (1 December 1997); doi: 10.1117/12.295527
Show Author Affiliations
Jonathan Partee, U.S. Dept. of Energy (United States)
Iowa State Univ. (United States)
Joseph Shinar, U.S. Dept. of Energy (United States)
Iowa State Univ. (United States)
Wilhelm Graupner, Technische Univ. Graz (Austria)
Guenther Leising, Technische Univ. Graz (Austria)
Scott W. Jessen, The Ohio State Univ. (United States)
Arthur J. Epstein, The Ohio State Univ. (United States)
Yi Wei Ding, Iowa State Univ. (United States)
Thomas J. Barton, U.S. Dept. of Energy (United States)
Iowa State Univ. (United States)


Published in SPIE Proceedings Vol. 3145:
Optical Probes of Conjugated Polymers
Z. Valy Vardeny; Lewis J. Rothberg, Editor(s)

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