Highly sensitive two-photon chromophores applied to three-dimensional lithographic microfabrication: design, synthesis and characterization towards two-photon absorption cross section
作者:Youmei Lu、Fuyuki Hasegawa、Takamichi Goto、Satoshi Ohkuma、Setsuko Fukuhara、Yukie Kawazu、Kenro Totani、Takashi Yamashita、Toshiyuki Watanabe
DOI:10.1039/b309023j
日期:——
A series of D–π–A–π–D type chromophores were synthesized by the dehydration reaction of 4-R2N-benzaldehye (R = Ph, Bun, Et, Me) and diaminomaleonitrile (corresponding to the chromophores 1, 2, 3 and 4, respectively), in which a polar imino double bond (–CN–) replaced the double bond (–CHCH–) in the π-conjugated centers. Femtosecond laser induced fluorescence intensity was used to evaluate two-photon absorption (TPA) cross sections, δ, using a USB-2000 CCD. Results show a change of terminal groups from Ph2N– to Me2N– influenced the δ value significantly through a change of the quantum yield, φ. However, the two-photon absorption peak position was only slightly affected. The chromophores 2 and 3 were found to afford polymers in the presence of the functional triacrylate monomer at low laser power at 755 and 820 nm. This demonstrated that the enhanced δ value was not a main factor in the improvement of chromophore two-photon photosensitivity. Such information can be useful in the design of more efficient two-photon chromophores for imaging and power-limiting applications.
通过 4-R2N 苯甲醛(R = Ph、Bun、Et、Me)和二氨基马来腈(分别对应发色团 1、2、3 和 4)的脱水反应合成了一系列 D-π-A-π-D 型发色团,其中极性亚氨基双键(-CN-)取代了 π 共轭中心的双键(-CHCH-)。利用 USB-2000 CCD,用飞秒激光诱导荧光强度来评估双光子吸收(TPA)截面δ。结果表明,将末端基团从 Ph2N- 转变为 Me2N-,会通过量子产率 φ 的变化对 δ 值产生显著影响。在 755 纳米和 820 纳米的低激光功率下,发色团 2 和 3 在功能性三丙烯酸酯单体的存在下生成聚合物。这表明,δ 值的提高并不是改善发色团双光子光敏性的主要因素。这些信息有助于设计更高效的双光子发色团,用于成像和功率限制应用。