| Six new chromophores have been synthesized by Vilsmier, Wittig and Heck reactions: 4-n-butyloxy-styryl-triphenylamine(Tl), bis-(4-n-butyloxy-styryl-triphenylamine)(T2), tri-(4-n-butyloxy-styryl-triphenylamine)(T3) , 2,8-bis(4'-triphenylamine-vinyl)-dibenzo-thiophene(ST-G1), 2,8-bis[4'-di-4",4'"-di(p-n-butyloxy-styryl)-triphenylamine-vinyl]-di-benzothiophene(ST-Gl') , and 2,8-bis[4'-di-4",4'"-p-(triphenylamine-vinyl)-tri-phenyl-amine-vinyl]-dibenzothiophene(ST-G2). Investigation in photoluminescence properties and two-photon fluorescence of these six compounds in different solvents have shown:(1) The chromophores have strong emissive ability of fluorescence. The results have shown that the maximum fluorescence wavelength of six chromophores were red-shifted when the polarity of solvents were increased. Similarly, the maximum fluorescence wavelength is Einstein shift in the same solution with the conjugated degree increasing.(2) T3, ST-G1' and ST-G2 have the same fluorescent behavior as "D-π-A" type molecular materials in solution.(3) There may exist two emission mechanism, i.e. ICT and TICT state functioning in different solvents. These two emission state can transform in proper condition.(4) T1, T2, T3, ST-G1 and ST-G1' showed strong two-photon pumped up-conversion emission. The one-photon-excited and the two-photon-excited fluorescence behaviors are very much similar, suggestion that both to be the emission coming from the same excitation state.(5) It was found that ST-G1' have the biggest two-photon absorption cross section ( 6 tpa) as its rigid planar π-center and large conjugated extent. It is benefit to synthesize chromophores with large two-photon absorption cross section.
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