Functional Materials Design via Structural Regulation Originated from Ions Introduction: A Study Case in Cesium Iodate System
作者:Min Zhang、Cong Hu、Tushagu Abudouwufu、Zhihua Yang、Shilie Pan
DOI:10.1021/acs.chemmater.7b05252
日期:2018.2.13
Tailored structural regulation to achieve novel compounds with special properties is very attractive and important for functional material design. In this paper, CsIO3 was selected as a maternal structure and three new derivatives, namely, CsIO2F2, Cs3(IO2F2)3·H2O, and Cs(IO2F2)2·H5O2, were successfully prepared by introducing different units (F–, H2O, H5O2+, and IO2F2–) under hydrothermal condition for the first time. Then, the structural transformations were schematically analyzed and the corresponding properties originated from ions introduction were investigated. Therein, noncentrosymmetric CsIO3 and CsIO2F2 exhibit good nonlinear optical properties with large second-harmonic generation (SHG) effects (15 × and 3 × KH2PO4), wide band gaps (4.2 and 4.5 eV), wide transmittance ranges (∼0.27–5.5 μm), and high laser damage thresholds (15 × and 20 × AgGaS2, respectively), which shows that they are potential nonlinear optical materials in near-ultraviolet to mid-infrared. To further analyze the structure–properties relationship, the first-principles calculations are applied to explore the origins of the optical properties, such as birefringences and SHG responses. Moreover, the protonated (H5O2)+ cations in Cs(IO2F2)2·H5O2 imply that it may feature enhanced conductivity, which was tentatively verified by the resistivity tests via the conventional dc four-probe method. The study case of structural regulation realized by ions introduction in this work may give a feasible guidance for functional materials design.
通过量身定制的结构调整来获得具有特殊性质的新型化合物,这对于功能材料的设计非常有吸引力,也非常重要。本文选择 CsIO3 作为母体结构,首次在水热条件下引入不同单元(F-、H2O、H5O2+ 和 IO2F2-),成功制备了三种新的衍生物,即 CsIO2F2、Cs3(IO2F2)3-H2O 和 Cs(IO2F2)2-H5O2。然后,对其结构转变进行了示意性分析,并研究了离子引入所产生的相应性质。其中,非中心对称的 CsIO3 和 CsIO2F2 表现出良好的非线性光学特性,具有较大的二次谐波发生(SHG)效应(15 × 和 3 × KH2PO4)、宽带隙(4.2 和 4.5 eV)、宽透射率范围(∼0.27-5.5 μm)和高激光损伤阈值(分别为 15 × 和 20 × AgGaS2),这表明它们是近紫外至中红外的潜在非线性光学材料。为了进一步分析结构与性能之间的关系,研究人员应用第一性原理计算探讨了双折射和 SHG 响应等光学特性的起源。此外,Cs(IO2F2)2-H5O2 中的质子化 (H5O2)+ 阳离子意味着它可能具有增强的导电性,这一点已通过传统直流四探针法的电阻率测试得到初步验证。这项工作中通过引入离子实现结构调整的研究案例可为功能材料的设计提供可行的指导。