Results from femtosecondrpicosecond transient absorption spectra measurements in the near-infraredrvisible spectral region of the red form of a soluble polycarbazolyldiacetylene in a polyethylene matrix are reported. Intrachain singlet and triplet excitons are identified by the different dynamics of the photoinduced bands. The results are consistent with the ultrafast generation -200 fs. of triplet pairs by fission of a singlet state located below the first optically allowed electronic state. In the picosecond time domain, triplet pairs undergo a random walk in a one-dimensional path with statistically distributed traps and partially dissociate into long-lived (150 micros. localized triplets.
TRIPLET EXCITON GENERATION AND DECAY IN A RED POLYDIACETYLENE STUDIED BY FEMTOSECOND SPECTROSCOPY
COMORETTO, DAVIDE;CUNIBERTI, CARLA EMILIA;MUSSO, GIANFRANCO;DELLEPIANE, GIOVANNA
1999-01-01
Abstract
Results from femtosecondrpicosecond transient absorption spectra measurements in the near-infraredrvisible spectral region of the red form of a soluble polycarbazolyldiacetylene in a polyethylene matrix are reported. Intrachain singlet and triplet excitons are identified by the different dynamics of the photoinduced bands. The results are consistent with the ultrafast generation -200 fs. of triplet pairs by fission of a singlet state located below the first optically allowed electronic state. In the picosecond time domain, triplet pairs undergo a random walk in a one-dimensional path with statistically distributed traps and partially dissociate into long-lived (150 micros. localized triplets.
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