Exciton-exciton scattering in disordered linear chains of poly(di-n-hexylsilane) - art. no. 115417

Citation
M. Shimizu et al., Exciton-exciton scattering in disordered linear chains of poly(di-n-hexylsilane) - art. no. 115417, PHYS REV B, 6411(11), 2001, pp. 5417
Citations number
37
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
PHYSICAL REVIEW B
ISSN journal
0163-1829 → ACNP
Volume
6411
Issue
11
Year of publication
2001
Database
ISI
SICI code
0163-1829(20010915)6411:11<5417:ESIDLC>2.0.ZU;2-X
Abstract
We have measured the time response of photoluminescence intensity in poly(d i-n-hexylsilane) films at 2 K with excitation densities from 1.2 x 10(17) t o 1.1 x 10(19) excitons cm(-3). At the highest density, the photoluminescen ce has a rise time of 1.4 ps, which is ascribed to the exciton-exciton scat tering time between initially photogenerated excitons. The inverse of rise times are sublinear to the excitation densities. The decay profiles are exp lained by the exciton-exciton annihilation with a rate constant of 1.0 +/- 0.5) x 10(-8) cm(3) s(-1). These processes are discussed in terms of excito n wave functions obtained by the one-dimensional Frenkel exciton model with disorder. We propose directional relaxation of excitons toward interacting points between different polymer chains as a mechanism for the efficient e xciton-exciton annihilation.