Symmetric and asymmetric charge transfer process of two-photon absorbing chromophores: bis-donor substituted stilbenes, and substituted styrylquinolinium and styrylpyridinium derivatives

Citation
Xm. Wang et al., Symmetric and asymmetric charge transfer process of two-photon absorbing chromophores: bis-donor substituted stilbenes, and substituted styrylquinolinium and styrylpyridinium derivatives, J MAT CHEM, 11(6), 2001, pp. 1600-1605
Citations number
28
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science","Material Science & Engineering
Journal title
JOURNAL OF MATERIALS CHEMISTRY
ISSN journal
0959-9428 → ACNP
Volume
11
Issue
6
Year of publication
2001
Pages
1600 - 1605
Database
ISI
SICI code
0959-9428(2001)11:6<1600:SAACTP>2.0.ZU;2-X
Abstract
Two-photon absorption properties of a series of symmetrically substituted s tilbenes and asymmetrically substituted stilbene-type derivatives with the same conjugated length have been investigated. The effective two-photon abs orption cross sections, delta (TPA), as large as 62.0 x 10(-48) cm(4) s pho ton(-1) for D-pi -D molecules and 48.5 x 10(-48) cm(4) s photon(-1) for D-p i -A counterparts have been observed. The effect of these two types of chro mophores on the peak position of the linear absorption, one-photon fluoresc ence as well as two-photon absorptivity is reported. Dipole moment change b etween the ground and the first excited states (Delta mu (ge)), and the tra nsition dipole moment between the first and second excited states (M-ee') h ave also been calculated. It was found that the asymmetrically substituted derivatives possess relatively large Delta mu (ge), whereas the symmetrical counterparts show an increase in M-ee'. Although a large two-photon absorp tion resonance is due to the simultaneously high values of M-ee' and Delta mu (ge), correlated to intramolecular charge transfer, the former function is larger. These results obtained have demonstrated that the magnitude and the peak position of two-photon absorption depend not only on the amount bu t also on the direction of the intramolecular charge transfer.