Photoresponsive J-aggregation behavior of a novel azobenzene-phthalocyanine dyad and its third-order optical nonlinearity.
J Phys Chem B
; 112(25): 7387-94, 2008 Jun 26.
Article
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| MEDLINE
| ID: mdl-18512976
The photoresponsive J-aggregation behaviors of a novel azobenzene-substituted zinc phthalocyanine (azo-ZnPc dyad) were studied by UV/vis, fluorescence, and (1)H NMR spectroscopy. Upon illumination with 365 nm UV light, the trans-cis isomerization of azobenzene can efficiently reduce the steric hindrance around the peripheral oxygen atom of azo-ZnPc, shortening the possible distance between two phthalocyanine molecules and, consequently, greatly improving the tendency of J-aggregation of azo-ZnPc dyad. The third-order optical nonlinearities of the photoresponsive J-aggregates (before and after illumination) were measured by a Z-scan technique at 532 nm with a pulse duration of 25 ps. The Z-scan spectra revealed that all the samples possessed large positive nonlinear refraction and positive nonlinear absorption, exhibiting a self-focusing effect and reverse saturable absorption, respectively. The second molecular hyperpolarizabilities of the dyad in two conditions were measured to be 3.87 x 10(-30) and 4.82 x 10(-30) esu, respectively. All the results suggest that the azo-ZnPc dyad has potential in the field of nonlinear optics applications.
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01-internacional
Base de datos:
MEDLINE
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En
Revista:
J Phys Chem B
Asunto de la revista:
QUIMICA
Año:
2008
Tipo del documento:
Article
Pais de publicación:
Estados Unidos