Probing the Strong Near-IR Two-Photon Transition in Supramolecular Triphenylamine-based Polymers by Nonlinear Absorption Spectroscopy.,The Journal of Physical Chemistry B

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Probing the Strong Near-IR Two-Photon Transition in Supramolecular Triphenylamine-based Polymers by Nonlinear Absorption Spectroscopy.
The Journal of Physical Chemistry B ( IF 2.8 ) Pub Date : 2020-06-15 , DOI: 10.1021/acs.jpcb.0c04127
Jessica Dipold ₁ , Marcelo G Vivas ₂ , Guy Koeckelberghs ₃ , Jonathas P Siqueira _{1,

4} , Leonardo De Boni ₁ , Cleber R Mendonca ₁

Affiliation

Due to their capability of film formation and remarkable optical features, semiconductor polymers with high two-photon absorption (2PA) have been studied as potential candidates for the development of organic photonic platforms. Furthermore, there is a high demand for photonic devices operating in the near-infrared (IR) region. However, the magnitude of the nonlinear optical response of random coil polymers in the IR region is weak due to the loss of molecular structure caused by increasing the π-conjugated backbone. Thus, herein we aim to investigate the molecular structure and 2PA features relationship for four polymers with supramolecular (helical) rodlike structure. Such polymers have a rigid core based on triphenylamine groups connected to the chiral binaphthalene units and a strong electron-withdrawing group (EWG). This kind of structure allows a very high chromophore density, which was responsible for generating 2PA cross-section between 305 GM and 565 GM in the near-IR (900–1300 nm), depending on the EWG strength. in light of the two-level model within the sum-overstates approach, we estimated the degree of intramolecular charge transfer induced by 2PA in the IR region, and values as high as 50–70% were found. Such a critical outcome allows the 2PA cross-section in the IR region to remain high even though the ratio between the visible/IR-band 2PA cross-section increases as a function of EWG strength.

中文翻译：

通过非线性吸收光谱探测超分子三苯胺基聚合物中的强近红外双光子跃迁。

由于其成膜能力和出色的光学特性，具有高双光子吸收（2PA）的半导体聚合物已被研究为开发有机光子平台的潜在候选者。此外，对在近红外（IR）区域中运行的光子器件有很高的要求。然而，由于由π共轭骨架的增加引起的分子结构的损失，IR区域中的无规卷曲聚合物的非线性光学响应的强度很弱。因此，本文旨在研究四种具有超分子（螺旋）棒状结构的聚合物的分子结构和2PA特征关系。这样的聚合物具有基于与手性双萘单元连接的三苯胺基的刚性核和强吸电子基团（EWG）。这种结构允许很高的生色团密度，这取决于EWG强度，在近红外（900-1300 nm）中产生305 GM和565 GM之间的2PA截面。根据总和状态法中的两级模型，我们估计了2PA在红外区引起的分子内电荷转移的程度，发现其值高达50-70％。即使可见光/ IR波段的2PA横截面之间的比率随EWG强度的增加而增加，这种关键结果也可以使IR区域中的2PA横截面保持较高。我们估计了2PA在IR区域引起的分子内电荷转移的程度，发现该值高达50-70％。即使在可见光/ IR波段2PA横截面之间的比率随EWG强度的增加而增加，这种关键结果也可以使IR区域中的2PA横截面保持较高。我们估计了2PA在IR区域引起的分子内电荷转移的程度，发现该值高达50-70％。即使在可见光/ IR波段2PA横截面之间的比率随EWG强度的增加而增加，这种关键结果也可以使IR区域中的2PA横截面保持较高。

更新日期：2020-07-16

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