External electric field effects on state energy and photoexcitation dynamics of diphenylpolyenes

Takakazu Nakabayashi, Md Wahadoszamen, Nobuhiro Ohta

Research output: Contribution to journalArticlepeer-review

40 Citations (Scopus)

Abstract

External electric field effects on state energy and photoexcitation dynamics have been examined for para-substituted and unsubstituted all-trans-diphenylpolyenes doped in a film, based on the steady-state and picosecond time-resolved measurements of the field effects on absorption and fluorescence. The substitution dependence of the electroabsorption spectra shows that the dipole moment of the substituted stilbene in the Franck-Condon excited state becomes larger with increasing difference between the Hammet constants of the substituents. Fluorescence quantum yields of 4-(dimethylamino)-4′- nitrostilbene and 4-(dimethylamino)-4′-nitrodiphenylbutadiene are markedly reduced by an electric field, suggesting that the rates of the intramolecular charge transfer (CT) from the fluorescent state to the nonradiative CT state are accelerated by an external electric field. The magnitude of the field-induced decrease in fluorescence lifetime has been evaluated. The isomerization of the unsubstituted all-trans-diphenylpolyenes to the cis forms is shown to be a significant nonradiative pathway even in a film. Field-induced quenching of their fluorescence as well as field-induced decrease in fluorescence lifetime suggests that the trans to cis photoisomerization is enhanced by an electric field.

Original languageEnglish
Pages (from-to)7041-7052
Number of pages12
JournalJournal of the American Chemical Society
Volume127
Issue number19
DOIs
Publication statusPublished - 2005 May 18
Externally publishedYes

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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