EXCITON DYNAMICS AND HIDDEN STRUCTURES OF POLY(DI-N-HEXYLSILANE) FILM- EXPERIMENTAL AND THEORETICAL-STUDY

We report here the measurements of the absorption spectra, photolumine scence spectra and the time response of the luminescence intensity in poly(di-n-hexylsilane) film at 2 K. The excitation energy dependence o f the luminescence peak and the rise time of 70 ps are observed. In or der to explain these results, numerical diagonalization of a one-dimen sional Frenkel exciton Hamiltonian with disorder has been carried out, and the luminescent process is formulated with the assumption that th e exciton does not change the site by phonon scattering. We have estim ated the transition dipole moment mu(0) = 0.93 x 10(-29) Cm and the tr ansition time c(tr) = 1.2 x 10(12) s(-1). We also discuss the role of hidden structures at the low-lying exciton states which appear in the site representation of exciton wave functions. (C) 1998 Elsevier Scien ce B.V. All rights reserved.