Solvent effect on two-photon absorption (TPA) of three novel dyes with large TPA cross-section and red emission

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• 作者：Yiqun Tan^a ; Qiong Zhang^b ; Jiancan Yu^a ; Xue Zhao^c ; Yupeng Tian^b ; Yuanjing Cui^a ; Xiaopeng Hao^c ; Yu Yang^a ; ^{yuyang@zju.edu.cn} ; Guodong Qian^a ; ^{gdqian@zju.edu.cn}
• 关键词：Nonlinear optics ; Quadrupolar compounds ; Two-photon absorption ; Fluorescence ; Intramolecular charge transfer ; Solvent effect
• 刊名：Dyes and Pigments
• 出版年：2013
• 出版时间：April, 2013
• 年：2013
• 卷：97
• 期：1
• 页码：58-64
• 全文大小：823 K

文摘

Three novel organic dyes containing 2,6-dicarbonyl-pyridine as the central electron acceptor with different end-caped amino groups as donors in the D-¦Ð-A-¦Ð-D arrangement are designed and synthesized. All three molecules exhibit large TPA cross-sections (¦Ä?>?1000?GM). The cooperative effects of donor strength, conjugation length and solvent polarity on the TPA activity are studied. The conjugated system plays an important role on the enhancement of ¦Ä in the highly polar solvent, while donor strength has more impact on TPA properties. The influence of the solvent polarity on TPA properties is studied by two-photon excited fluorescence (TPEF) measurement. The result shows a nonmonotonic relationship between the TPA cross-section and the solvent, and the maximum of ¦Ä is found in solvents with moderate polarity. The ¦Ä of molecules with stronger donor reaches the maximum in more polar solvents. The highest ¦Ä is found to be 5250?GM in CHCl₃. All compounds exhibit large Stokes shifts due to the strong intramolecular charge transfer (ICT) effect.