We have measured the time response of luminescence intensity in poly(di-n-hexylsilane) films with the excitation density from 1.2 × 1018 to 1.1 × 1020 excitons cm-3 at 2 K. At 1.1 × 1020 cm-3, we found that the rise times is 1.4 ± 0.5 ps and that the decay is nonexponential. The rise time is attributed to the exciton-exciton scattering time in which initially photo-generated excitons at 4 eV are scattered to the luminescent states at 3.4 eV. The nonexponential decay is ascribed to the bimolecular annihilation of excitons with the rate constant γ2 of (1.0 ± 0.5) × 10-8 cm3 s-1. A microscopic mechanism to explain this large γ2 is discussed.
|Number of pages||3|
|Journal||Journal of Luminescence|
|Publication status||Published - 2000 May|
|Event||International Conference on Luminescence and Optical Spectroscopy of Condensed Matter (ICL'99) - Osaka, Jpn|
Duration: 1999 Aug 23 → 1999 Aug 27