title: Two photon absorption properties of 1,3,5-tricyano-2,4,6-tris(styryl)benzene derivatives.
abstract: Two-photon absorption (TPA) properties of 1,3,5-tricyano-2,4,6-tris(styryl)benzene derivatives have been investigated. Comparison of the absorption and fluorescence spectra reveals that these compounds show large Stokes shifts, which increase gradually as the conjugation length increases. One-photon absorption and excitation spectra are similar except that the latter exhibit several peaks near lambda(max). It is also found that the one- and two-photon-induced fluorescence excitation spectra are quite similar, which indicates that the one- and two-photon allowed-excited states are the same. The peak TPA cross section values (delta(max)) measured with nanosecond pulses by the two-photon-induced fluorescence method are in the range (50-2620) x 10(-50) cm4 s/photon. The delta(max) value increases as the donor strength and conjugation length increase. A linear relationship is observed between delta(max) and beta, and this delta-beta relationship is found to serve as a useful synthetic strategy for the design of novel TPA dyes with the octupolar structure.
authors.affiliation: Molecular Opto-Electronics Laboratory, Department of Chemistry and Center for Electro- & Photo-Responsive Molecules, Korea University, 1-Anamdong, Seoul 136-701, Korea.
authors.forename: B R
authors.initials: BR
authors.lastname: Cho
authors.forename: K H
authors.initials: KH
authors.lastname: Son
authors.forename: S H
authors.initials: SH
authors.lastname: Lee
authors.forename: Y S
authors.initials: YS
authors.lastname: Song
authors.forename: Y K
authors.initials: YK
authors.lastname: Lee
authors.forename: S J
authors.initials: SJ
authors.lastname: Jeon
authors.forename: J H
authors.initials: JH
authors.lastname: Choi
authors.forename: H
authors.initials: H
authors.lastname: Lee
authors.forename: M
authors.initials: M
authors.lastname: Cho