Xiao Rui, Yao Wen-Dong, Xing Wenhao, Tang Chunlan, Jiang Wenwen, Guo Sheng-Ping, Yin Wenlong
Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang 621900, P. R. China.
Yunnan Key Laboratory of Electromagnetic Materials and Devices, National Center for International Research on Photoelectric and Energy Materials, School of Materials and Energy, Yunnan University, Kunming 650500, P. R. China.
Inorg Chem. 2025 Jul 21;64(28):14437-14444. doi: 10.1021/acs.inorgchem.5c01715. Epub 2025 Jul 9.
Adjusting the structure of compounds through an anion partial substitution strategy is an effective means to explore nonlinear optical (NLO) materials. Here, a new oxysulfide CaGeOS (CGOS) crystallized in the centrosymmetric (CS) space group 2/ was synthesized by a high-temperature solid-solid reaction. Taking CGOS as the parent, the first quaternary NLO Ca-based oxyselenide CaGeOSe (CGOSe) crystallized in the noncentrosymmetric (NCS) space group 3 was obtained by anion partial substitution. The 0D structure of CGOS consists of isolated [GeOS] dimers, with Ca ions located between dimers to balance the charge. The 0D structure of CGOSe consists of isolated and parallelly arranged [GeOSe] dimers, with Ca ions located between dimers to balance the charge. The structural evolution between CGOS and CGOSe is elucidated. CGOSe has the widest band gap of 3.02 eV in the AEGeOQ (AE = Ca, Sr, Ba; Q = S, Se, Te) system. Apart from the obvious NLO activity, CGOSe exhibits a high laser-induced damage threshold of around 3.2 × AgGaS. The theoretical calculation results show that the [GeOSe] dimer is the main source of the SHG response. This work enriches the relatively less-explored Ca-based oxychalcogenides as NLO materials.
通过阴离子部分取代策略调整化合物结构是探索非线性光学（NLO）材料的有效手段。在此，通过高温固-固反应合成了一种在中心对称（CS）空间群2/中结晶的新型氧硫化物CaGeOS（CGOS）。以CGOS为母体，通过阴离子部分取代获得了第一种在非中心对称（NCS）空间群3中结晶的四元NLO钙基氧硒化物CaGeOSe（CGOSe）。CGOS的零维结构由孤立的[GeOS]二聚体组成，钙离子位于二聚体之间以平衡电荷。CGOSe的零维结构由孤立且平行排列的[GeOSe]二聚体组成，钙离子位于二聚体之间以平衡电荷。阐明了CGOS和CGOSe之间的结构演变。在AEGeOQ（AE = Ca、Sr、Ba；Q = S、Se、Te）体系中，CGOSe具有3.02 eV的最宽带隙。除了明显的NLO活性外，CGOSe还表现出约3.2×AgGaS的高激光损伤阈值。理论计算结果表明，[GeOSe]二聚体是SHG响应的主要来源。这项工作丰富了作为NLO材料而研究相对较少的钙基氧硫族化合物。
