Femtosecond time-resolved laser action in poly( p-phenylene vinylene) films: stimulated emission in an inhomogeneously broadened exciton distribution

Femtosecond time-resolved studies of photoluminescence (PL) and stimulated emission (SE) have been conducted in neat thin films of poly( p-phenylene vinylene) derivatives. For high excitation intensity I, we found that the SE spectral narrowing is accompanied by a dramatic lifetime shortening from ∼...

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Bibliographic Details
Published in:Chemical physics letters 1999-12, Vol.314 (5), p.564-569
Main Authors: Lee, C.W, Wong, K.S, Huang, J.D, Frolov, S.V, Vardeny, Z.V
Format: Article
Language:English
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Summary:Femtosecond time-resolved studies of photoluminescence (PL) and stimulated emission (SE) have been conducted in neat thin films of poly( p-phenylene vinylene) derivatives. For high excitation intensity I, we found that the SE spectral narrowing is accompanied by a dramatic lifetime shortening from ∼250 to ∼3 ps, which enhances energy migration within the inhomogeneously broadened exciton distribution. In addition, the SE is delayed with respect to the PL onset by a few picoseconds, depending on I and the illumination stripe length. In some cases, a second delayed SE is formed in the film due to the continuing energy migration into exciton states with superior radiative coupling.
ISSN:0009-2614
1873-4448
DOI:10.1016/S0009-2614(99)01178-1