Abstract
This paper is a review of already published work. Exciton-relaxation processes in organic solids are discussed. Pyrene and poly(phenylenevinylene) (PPV) crystals are investigated as two examples of strong exciton–phonon coupled systems. Free-exciton luminescence is observed simultaneously with self-trapped exciton luminescence in these crystals. Since the presence of a self-trapping (a barrier that separates the free-exciton state from the self-trapped exciton state) directly affects the exciton-relaxation process and excimer (self-trapped exciton) -formation time, attention is focused to reveal the presence of the barrier. The intensity and the decay time of transient free-exciton luminescence are discussed, as is the rise of self-trapped exciton luminescence. The exciton-relaxation path within the free-exciton band is also discussed. In pyrene above 120 K, the structural phase-transition point, most of the photoproduced excitons relax directly toward the self-trapped state, and only a small fraction of them relax to the bottom of the free-exciton band. At temperatures below 60 K no exciton relaxes to the bottom of the free-exciton band, except in the case when excitons are produced close to the bottom of the free-exciton band. In PPV all the photoproduced excitons relax to the bottom of the free-exciton band.
© 1990 Optical Society of America
Full Article | PDF ArticleMore Like This
Takayoshi Kobayashi, Masayuki Yoshizawa, Uwe Stamm, Makoto Taiji, and Masamitsu Hasegawa
J. Opt. Soc. Am. B 7(8) 1558-1578 (1990)
A. Antonetti, D. Hulin, A. Migus, A. Mysyrowicz, and L. L. Chase
J. Opt. Soc. Am. B 2(7) 1197-1203 (1985)
M.-C. Nadeau, G. Duchateau, M. Dumergue, N. Fedorov, D. Descamps, S. Petit, G. Geoffroy, and P. Martin
J. Opt. Soc. Am. B 35(5) 1119-1126 (2018)