Strong two-photon absorption and two-photon excited fluorescence emission of heterofluorene derivatives

✍ Scribed by Xiaomei Wang; Ping Yang; Wanli Jiang; Guibao Xu; Xiaozhi Guo

• Publisher: Elsevier Science
• Year: 2005
• Tongue: English
• Weight: 498 KB
• Volume: 27
• Category: Article
• ISSN: 0925-3467
• DOI: 10.1016/j.optmat.2004.08.081

✦ Synopsis

Two new chromophores: 2,8-bis[2-(4 0 -ethoxylphenyl)-5-(4 0 -styryl)-1,3,4-oxadiazole]dibenzothiophene (abbreviated as SO-G1) and 2,8-bis[(2-(4 0 -ethoxylphenyl)-5-(4 0 -styryl)-1,3,4-oxadiazole-N-ethylcarbazole (abbreviated as NO-G1) that exhibit strong twophoton absorption and enhanced two-photon excited fluorescence were synthesized based on ''push-pull-core-pull-push'' elongated molecules built from a rigid dibenzothiophene or carbazole. Both chromophores in different solvent are highly transparent across almost the whole visible spectrum region and possess highest fluorescence quantum yield of 0.89 for NO-G1 and 0.46 for SO-G1. Pumped by a visible wavelength (700-800 nm) of Ti: sapphire femto-second laser pulses, strong two-photon excited (TPE) fluorescence located at 440-510 nm with the TPE fluorescence emission cross-section (d TPF ) being 21-8.2 times as much as that of fluorescein reference and strong two-photon absorption (TPA) cross-section (d TPA ) of 454-377 GM have been observed.