Enhanced piezoresponse and nonlinear optical properties of fluorinated self-assembled peptide nanotubes
Enhanced piezoresponse and nonlinear optical properties of fluorinated self-assembled peptide nanotubes
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DOI：
10.1063/1.5110562
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发表时间：
2019-11-01
期刊：
影响因子：
1.6
通讯作者：
Guha, Suchismita
中科院分区：
文献类型：
--
作者：
Khanra, Soma;Vassiliades, Sandra V.;Guha, Suchismita
自组装L，L-二苯基丙氨酸（FF）纳米结构为光子学和非线性光学提供了一个有吸引力的平台。FF纳米管的非线性光学（NLO）系数依赖于管的直径[S. Khanra等人，Phys.Chem.Chem.Phys.19（4），3084-3093（2017）]。为了进一步增强FF的NLO性质，我们寻找结构修饰。在这里，我们报告的合成氟化FF二肽取代一个邻氢原子在每个FF的苯基由氟原子。密度泛函理论计算产生的见解氟化FF（F1-FF）的最低能量构象。Fl-FF类似于FF自组装成微米长度的管。研究了掺杂对薄膜压电响应和非线性光学特性的影响。发现Fl-FF的压电d（15）系数比FF纳米管的压电d（15）系数高10倍以上，并且单个Fl-FF纳米管的二次谐波产生（SHG）偏振强度是单个FF纳米管的20倍以上。此外，我们获得了SHG图像，以比较FF和F1-FF管的强度。这项工作表明了氟取代在其他自组装仿生肽中用于增强非线性光学响应和压电性的潜力。(C)2019年作者。
Self-assembled L,L-diphenylalanine (FF) nanostructures offer an attractive platform for photonics and nonlinear optics. The nonlinear optical (NLO) coefficients of FF nanotubes depend on the diameter of the tube [S. Khanra et al. Phys. Chem. Chem. Phys. 19(4), 3084-3093 (2017)]. To further enhance the NLO properties of FF, we search for structural modifications. Here, we report on the synthesis of fluorinated FF dipeptides by replacing one ortho-hydrogen atom in each of the phenyl groups of FF by a fluorine atom. Density-functional theoretical calculations yield insights into minimum energy conformers of fluorinated FF (Fl-FF). Fl-FF self-assembles akin to FF into micron-length tubes. The effects of fluorination are evaluated on the piezoelectric response and nonlinear optical properties. The piezoelectric d(15) coefficient of Fl-FF is found to be more than 10 times higher than that of FF nanotubes, and the intensity of second harmonic generation (SHG) polarimetry from individual Fl-FF nanotubes is more than 20 times that of individual FF nanotubes. Furthermore, we obtain SHG images to compare the intensities of FF and Fl-FF tubes. This work demonstrates the potential of fluorine substitution in other self-assembled biomimetic peptides for enhancing nonlinear optical response and piezoelectricity. (C) 2019 Author(s).