<i>trans</i>/<i>cis</i>-Isomerization of Fluorene-Bridged Azo Chromophore with Significant Two-Photon Absorbability at Near-Infrared Wavelength
作者:Chih-Chien Chu、Ya-Chi Chang、Bo-Kai Tsai、Tzu-Chau Lin、Ja-Hon Lin、Vincent K. S. Hsiao
DOI:10.1002/asia.201402896
日期:2014.12
efficient blue‐light‐induced trans‐to‐cis photoisomerization with a rate constant of 2.04×10−1 min−1 at the photostationary state (PSS). The open‐aperture Z‐scan technique that adopted a femtosecond (fs) pulse laser as excitation source shows an appreciably higher 2PA cross‐section for the fluorene‐derived azo chromophore than that for common azobenzene dyes at near‐infrared wavelength (λex=800 nm). Furthermore
含偶氮材料已被证明具有二阶非线性光学(NLO)特性,但是涉及三光子吸收(2PA)的三阶NLO特性却鲜有报道。在这项研究中,我们证明了新型的偶氮发色团与双边二苯氨基芴(DPAFs)作为π骨架的显着2PA行为。作为供电子性基团DPAF引起红移π-π*吸收带中心在470nm,因此允许高效的蓝色光诱导的反式-到-顺光异构化用的2.04×10的速率常数-1 分钟-1的photostationary状态(PSS)。开孔Z采纳了飞秒(fs)的脉冲激光器作为激励光源示出了相当高的2PA横截面为芴衍生的偶氮发色团比用于在近红外波长共同偶氮苯染料(〜扫描技术λ EX = 800纳米)。此外,无论分子几何形状如何,fs 2PA响应都非常均匀。在计算模型的基础上,从外围二苯胺通过芴π桥到中心偶氮基团的分子内电荷转移(ICT)过程对于这种显着的2PA行为至关重要。