Ultrafast depolarization of the fluorescence in a conjugated polymer

TitleUltrafast depolarization of the fluorescence in a conjugated polymer
Publication TypeJournal Article
Year of Publication2005
AuthorsRuseckas, A., Wood P., Samuel I. D. W., Webster G. R., Mitchell W. J., Burn P. L., and Sundstrom V.
JournalPhysical Review B
Date Publishedsep
AbstractThe effect of the extent of pi electron conjugation on the primary photophysics in semiconducting polymers is reported. A rapid depolarization of photoluminescence and transient absorption, which indicates a reorientation of the transition dipole moment by similar to 30 degrees on a sub-100 fs time scale, is observed in the fully conjugated polymer poly[2-(2'-ethylhexyloxy)-5-methoxy-1,4-phenylenevinylene] (MEH-PPV). In contrast, partially conjugated polymers exhibit a much slower depolarization. The results reveal rapid changes of exciton delocalization in the fully conjugated MEH-PPV driven by structural relaxation.