Exciton dynamics and hidden structures of poly(di-n-hexylsilane) film: Experimental and theoretical study

We report here the measurements of the absorption spectra, photoluminescence spectra and the time response of the luminescence intensity in poly(di-n-hexylsilane) film at 2 K. The excitation energy dependence of the luminescence peak and the rise time of 70 ps are observed. In order to explain these results, numerical diagonalization of a one-dimensional Frenkel exciton Hamiltonian with disorder has been carried out, and the luminescent process is formulated with the assumption that the exciton does not change the site by phonon scattering. We have estimated the transition dipole moment mu(0) = 0.93 x 10(-29) Cm and the transition 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 Science B.V. All rights reserved.