Excitation dynamics in sigma-pi conjugated silylene-biphenylene copolymers

We have measured absorption spectra, luminescence spectra and the time resp onse of luminescence intensity in sigma-pi conjugated polymers of silylene- biphenylene copolymers in tetrahydrofuran solution at room temperature. In order to investigate the sigma-conjugated length dependence of optical prop erties, we have prepared the three copolymers which have different silylene chain lengths of m = 1, 2 and 6. It is found that the excitations are stro ngly localized at biphenylene units for m = 1 and that a strong lattice rel axation occurs for m = 2. For m = 6, the charge transfer excitation from si lylene units to biphenylene units is indicated. (C) 2000 Elsevier Science B .V. All rights reserved.