Synthesis, characterization, and optical properties of two-photon-absorbing octupolar molecule with an s-triazine core

✍ Scribed by Feng Xu; Zhenwei Wang; Qihuang Gong

• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 159 KB
• Volume: 29
• Category: Article
• ISSN: 0925-3467
• DOI: 10.1016/j.optmat.2005.12.003

✦ Synopsis

The octupolar molecule with s-triazine as the p-electron deficient core, N-ethylcarbazole groups as the electron-donating end-groups, 2,4,6-tris[2-(N-ethyl-3-carbazole)carboxethenyl]-1,3,5-s-triazine(III), was prepared. The assemblies of III,2,carboxethenyl]-1,3,5-s-triazine(I), and 2-methyl-4,6-bis [2-(N-ethyl-3-carbazole)carboxethenyl]-1,3,5-s-triazine(II), were also prepared. The linear and nonlinear spectra of these compounds regularly vary: (1) the spectral positions (k max values) of the linear absorption, the one-photon excited fluorescence (OPEF) and the two-photon excited fluorescence (2PEF) show regular red-shifts when the branch number increases from I to III; (2) the OPEF and the 2PEF intensities are all increased significantly when going from I to III. Excited by femtosecond laser at 800 nm wavelength, the fluorescence intensities of II, III show a quadratic dependence on the pump intensity, suggesting that the emission originates from a 2PA process. Two-photon absorption (2PA) cross-section of II, III is 397 GM and 994 GW, respectively. The value of r 2 /MW of II, III varies with the ratio of 1.0:1.8.