Shin Bong-Rim, Puc Uros, Park Yu-Jin, Kim Dong-Joo, Lee Chae-Won, Yoon Woojin, Yun Hoseop, Kim Chaeyoon, Rotermund Fabian, Jazbinsek Mojca, Kwon O-Pil
Department of Molecular Science and Technology, Ajou University, Suwon, 16499, South Korea.
Institute of Computational Physics, Zurich University of Applied Sciences (ZHAW), Winterthur, 8401, Switzerland.
Adv Sci (Weinh). 2023 Dec;10(34):e2304767. doi: 10.1002/advs.202304767. Epub 2023 Oct 22.
In the development of new organic crystals for nonlinear optical and terahertz (THz) applications, it is very challenging to achieve the essentially required non-centrosymmetric molecular arrangement. Moreover, the resulting crystal structure is mostly unpredictable due to highly dipolar molecular components with complex functional substituents. In this work, new organic salt crystals with top-level macroscopic optical nonlinearity by controlling the van der Waals volume (V ), rather than by trial and error, are logically designed. When the V of molecular ionic components varies, the corresponding crystal symmetry shows an observable trend: change from centrosymmetric to non-centrosymmetric and back to centrosymmetric. All non-centrosymmetric crystals exhibit an isomorphic P1 crystal structure with an excellent macroscopic second-order nonlinear optical response. Apart from the top-level macroscopic optical nonlinearity, new organic crystals introducing highly electronegative fluorinated substituents with strong secondary bonding ability show excellent performance in efficient and broadband THz wave generation, high crystal density, high thermal stability, and good bulk crystal growth ability.
在开发用于非线性光学和太赫兹（THz）应用的新型有机晶体时，实现基本所需的非中心对称分子排列极具挑战性。此外，由于具有复杂功能取代基的高偶极分子成分，所得晶体结构大多不可预测。在这项工作中，通过控制范德华体积（V）而非反复试验，合理设计出具有顶级宏观光学非线性的新型有机盐晶体。当分子离子成分的V发生变化时，相应的晶体对称性呈现出可观察到的趋势：从中心对称变为非中心对称，再变回中心对称。所有非中心对称晶体均呈现同构的P1晶体结构，具有出色的宏观二阶非线性光学响应。除了顶级宏观光学非线性外，引入具有强二级键合能力的高电负性氟化取代基的新型有机晶体在高效宽带太赫兹波产生、高晶体密度、高热稳定性和良好的块状晶体生长能力方面表现出色。
