Yue Qing-Gang, Zhou Sheng-Hua, Li Bingxuan, Wu Xin-Tao, Lin Hua, Zhu Qi-Long
College of Chemistry, Fuzhou University, Fuzhou 350002, China.
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China.
Inorg Chem. 2022 Jan 24;61(3):1797-1804. doi: 10.1021/acs.inorgchem.1c03820. Epub 2022 Jan 11.
Multinary rare-earth chalcogenides with d-block transition metals have attracted considerable attention owing to their intriguing structural architectures and promising practical applications. In this work, three quaternary rare-earth sulfides, BaRECdS (RE = Sm, Gd, or Tb), have been obtained by the high-temperature solid-state method. These compounds are isostructural and belong to the noncentrosymmetric orthorhombic space group 2 (No. 36). The basic structural unit contains unique two-dimensional anionic [RECdS] layers, which are separated by Ba cations. Remarkably, BaSmCdS exhibits a high second-harmonic-generation intensity (1.8 times that of AgGaS) and a significantly higher laser-induced damage threshold (14.3 times that of AgGaS), which is the first case possessing an infrared (IR) nonlinear optical (NLO) property in the quaternary AE/RE/TM/Q (AE = alkaline-earth metals; RE = rare-earth metals; TM = d-block transition metals; and Q = chalcogen) systems. Moreover, theoretical investigations of the structure-property relationship indicate that the combined action of various types of NLO-active units makes the main contribution to the SHG activity. This discovery may shed light on broadening the frontiers of IR-NLO materials.
具有d 族过渡金属的多元稀土硫族化合物因其引人入胜的结构架构和颇具前景的实际应用而备受关注。在本工作中，通过高温固态法制备了三种四元稀土硫化物BaRECdS（RE = Sm、Gd或Tb）。这些化合物同构，属于非中心对称正交空间群2（编号36）。基本结构单元包含独特的二维阴离子[RECdS]层，由Ba阳离子分隔。值得注意的是，BaSmCdS表现出高的二次谐波产生强度（是AgGaS的1.8倍）和显著更高的激光诱导损伤阈值（是AgGaS的14.3倍），这是四元AE/RE/TM/Q（AE = 碱土金属；RE = 稀土金属；TM = d族过渡金属；Q = 硫族元素）体系中首例具有红外（IR）非线性光学（NLO）性质的情况。此外，对结构 - 性能关系的理论研究表明，各类NLO活性单元的共同作用对SHG活性起主要贡献。这一发现可能为拓宽红外NLO材料的前沿领域提供启示。
