中国海洋大学张弛团队报道了通过硫氰酸锌维数工程制备强紫外-可见-近红外二次谐波。相关研究成果发表在2024年10月7日出版的《美国化学会杂志》。

精确调制基元的空间取向和连接模式，对于非线性光学（NLO）材料的某些至关重要的光学功能（特别是二次谐波发生（SHG）和光学带隙）至关重要。然而，人们尚未对高效宽带非线性光学材料的设计结构实现足够的控制。

利用维度增加可能导致的微观极化变化，该文中，研究人员首次提出了一种零维（0D）到三维（3D）的维度增加策略，以实现强宽带SHG响应。通过去除SHG无活性的[NH₄]⁺抗衡阳离子和位于(NH₄)₂Zn(SCN)₄·3H₂O内相邻离散[Zn(SCN)₄]构建块。

从(NH₄)₂Zn(SCN)₄·3H₂O到Zn(SCN)₂的0D到3D维度工程，从紫外到近红外区域(SHG@300–1050nm）显著增强了SHG响应和高效的宽带活性（8×KH₂PO₄@1064 nm，前者c.f. 2 × β-BaB₂O₄ @ 380 nm带隙为4.18 eV, 30 × KH₂PO4 @ 1064 nm, 后者2 × KTiOPO₄ @ 2100 nm带隙为4.78 eV）。

理论计算和晶体结构分析表明，Zn(SCN)₂类金刚石结构内的配位键连接的[Zn(SCN)₄]构建块，是其巨大宽带SHG响应的原因。

附：英文原文

Title: Toward Strong UV–Vis–NIR Second-Harmonic Generation by Dimensionality Engineering of Zinc Thiocyanates

Author: Haijun Zhang, Xingxing Jiang, Yiran Zhang, Kaining Duanmu, Chao Wu, Zheshuai Lin, Jun Xu, Jinhu Yang, Zhipeng Huang, Mark G. Humphrey, Chi Zhang

Issue&Volume: October 7, 2024

Abstract: The precise modulation of the spatial orientations and connection modes of primitives is vital for certain critically important optical functions for nonlinear optical (NLO) materials (specifically, second-harmonic generation (SHG) and optical bandgap); however, we are yet to achieve a sufficient level of control for the designed construction of efficient broadband NLO materials. Exploiting the changes in microscopic polarization that may result from dimensional increase, we propose herein a zero-dimensional (0D)-to-three-dimensional (3D) dimensionality-increase strategy to realize strong broadband SHG responses for the first time. The novel 3D pseudo diamond-like Zn(SCN)2 has been synthesized by removing SHG-inactive [NH4]+ counter cations and H2O molecules that are located between the adjacent discrete [Zn(SCN)4] building blocks within the 0D (NH4)2Zn(SCN)4·3H2O. The 0D-to-3D dimensionality engineering, proceeding from (NH4)2Zn(SCN)4·3H2O to Zn(SCN)2, results in significantly enhanced SHG responses and efficient broadband activity (8 × KH2PO4 @ 1064 nm, 4.18 eV bandgap for the former c.f. 2 × β-BaB2O4 @ 380 nm, 30 × KH2PO4 @ 1064 nm, 2 × KTiOPO4 @ 2100 nm, 4.78 eV bandgap for the latter) from the UV to the NIR regions (SHG@300–1050 nm). Theoretical calculations and crystal structure analyses reveal that the coordination-bond-connected [Zn(SCN)4] building blocks within the diamond-like structure of Zn(SCN)2 are responsible for its giant broadband SHG responses.

DOI: 10.1021/jacs.4c09172

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.4c09172