Two-Photon Excited Fluorescence and Second-Harmonic Generation of the DAST Organic Nanocrystals

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• 作者：Mei-Ling Zheng ; Katsumasa Fujita ; Wei-Qiang Chen ; Xuan-Ming Duan ; Satoshi Kawata
• 刊名：Journal of Physical Chemistry C
• 出版年：2011
• 出版时间：May 12, 2011
• 年：2011
• 卷：115
• 期：18
• 页码：8988-8993
• 全文大小：921K
• 年卷期：v.115,no.18(May 12, 2011)
• ISSN：1932-7455

文摘

The nonlinear optical properties of the size-controlled trans-4-[4-(dimethylamino)-N-methylstilbazolium] p-tosylate (DAST) organic nanocrystals (ONCs) have been investigated. The size and monoclinic crystal structure have been demonstrated by the scanning electron microscope, transmission electron microscope, and X-ray diffraction measurement. The DAST ONCs exhibited 6-fold enhanced fluorescence quantum yield and prolonged fluorescence lifetime compared to DAST molecular solution. The evaluations of two-photon excited fluorescence (TPEF) and second-harmonic generation (SHG) microscopes have been implemented for investigating the optical nonlinearities of DAST nanocrystals. The TPEF intensity of DAST ONCs was improved by a factor of 37.3 compared to DAST molecular solution. The extraordinary large two-photon absorption cross section up to 1.72 脳 10⁶ GM was observed. DAST ONC was demonstrated as a single crystal from the four-lobe polarization response in the SHG microscope. These results would provide DAST ONCs the opportunity for the potential application in photonics and bioimaging as nonlinear optical materials.