trans/cis-Isomerization of fluorene-bridged azo chromophore with significant two-photon absorbability at near-infrared wavelength.
Chem Asian J
; 9(12): 3390-6, 2014 Dec.
Article
en En
| MEDLINE
| ID: mdl-25294108
Azo-containing materials have been proven to possess second-order nonlinear optical (NLO) properties, but their third-order NLO properties, which involves two-photon absorption (2PA), has rarely been reported. In this study, we demonstrate a significant 2PA behavior of the novel azo chromophore incorporated with bilateral diphenylaminofluorenes (DPAFs) as a π framework. The electron-donating DPAF moieties cause a redshifted π-π* absorption band centered at 470 nm, thus allowing efficient blue-light-induced trans-to-cis photoisomerization with a rate constant of 2.04 × 10(-1) min(-1) at the photostationary state (PSS). The open-aperture Z-scan technique that adopted a femtosecond (fs) pulse laser as excitation source shows an appreciably higher 2PA cross-section for the fluorene-derived azo chromophore than that for common azobenzene dyes at near-infrared wavelength (λex =800 nm). Furthermore, the fs 2PA response is quite uniform regardless of the molecular geometry. On the basis of the computational modeling, the intramolecular charge-transfer (ICT) process from peripheral diphenylamines to the central azo group through a fluorene π bridge is crucial to this remarkable 2PA behavior.
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1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Compuestos Azo
/
Fotones
/
Flúor
Idioma:
En
Revista:
Chem Asian J
Año:
2014
Tipo del documento:
Article
Pais de publicación:
Alemania