Liu Yi, Zhu Pengfei, Fan Qingshun, Zhao Zihao, Wei Linjie, Ma Yu, Xu Haojie, Guo Wuqian, Luo Junhua, Sun Zhihua
State Key Laboratory of Structure Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, 350002, P. R. China.
University of Chinese Academy of Sciences Beijing, Beijing, 100049, P. R. China.
Adv Sci (Weinh). 2025 Jan;12(3):e2412218. doi: 10.1002/advs.202412218. Epub 2024 Nov 24.
To modulate nonlinear optical (NLO) effects of crystalline material holds great application potential in the photoelectronic and optical fields. Organic configurationally-locked polyene represents an exciting NLO family with large second harmonic generation (SHG) effects, whereas it is a huge blank to switch and modulate their NLO property through external stimuli. For the first time, here present unusual thermo-enhanced SHG activities are presented in a polyene-based NLO compound, 2-{3-[2-(4-pyrrolidinphenyl)vinyl]-5,5-dimethylcyclohex-2-enylidene}malononitrile (1), giving a record-high magnitude of SHG enhancement up to ≈170% during its isomorphic phase transition. Theoretical analysis discloses this behavior stems from the reduced degree of torsion in the π-conjugated structures in 1, as verified by dihedral angles between its pyrrolidine and phenyl planes. As the first study on thermo-enhanced SHG properties of organic crystals, this work affords a new avenue of modulating physical properties to fabricate high-performance photoelectronic and optical devices.
调控晶体材料的非线性光学（NLO）效应在光电子和光学领域具有巨大的应用潜力。有机构型锁定多烯是一类令人兴奋的具有大二次谐波产生（SHG）效应的NLO家族，然而，通过外部刺激来切换和调制它们的NLO性质却是一个巨大的空白。在此，首次在一种基于多烯的NLO化合物2-{3-[2-(4-吡咯烷基苯基)乙烯基]-5,5-二甲基环己-2-亚基}丙二腈（1）中呈现出异常的热增强SHG活性，在其同构相变过程中，SHG增强幅度高达约170%，创历史新高。理论分析表明，这种行为源于1中π共轭结构的扭转程度降低，这一点通过其吡咯烷和苯平面之间的二面角得到了验证。作为对有机晶体热增强SHG性质的首次研究，这项工作为调制物理性质以制造高性能光电子和光学器件提供了一条新途径。
