Xu Jingjing, Xiao Yan, Wu Xiaowen, Zhang Bingbing, Wu Kui
State Key Laboratory of Crystal Materials and Institute of Crystal Materials, Shandong University, Jinan 250100, China.
College of Chemistry and Materials Science, Hebei University, Baoding 071002, China.
Dalton Trans. 2025 Mar 17;54(12):4903-4908. doi: 10.1039/d4dt03569k.
A combination of multiple anions (S and O) was developed as an effective method for exploring new, excellent nonlinear optical (NLO) oxysulfides with adjustable properties based on the flexible anion (S/O) ratio in their structures. It should be noted that mixed melilite-type oxysulfides, containing both alkaline earth (Ae) and trivalent lanthanide (Ln) metals, exhibit natural noncentrosymmetric (NCS) and disordered structures, demonstrating good NLO properties. Herein, we introduced low-coordination ZnS to replace high-coordination AeS in La-based melilite, thereby breaking the initial disordered structure and leading to the formation of a LaZnGaSO NLO material with an ordered structure. Property investigations showed that LaZnGaSO achieved a well-balanced NLO behavior, with a wide optical bandgap (3.0 eV) and an ultra-strong phase-matching second harmonic generation (SHG) response (1.9 × AgGaS). Among the melilite-type transition-metal oxysulfides, LaZnGaSO exhibited the largest powder SHG response, which was attributed to the synergetic contributions of LaSO, ZnS and GaSO anionic groups, based on SHG-density analysis. This indicates that LaZnGaSO is a potential NLO candidate for frequency conversion applications, and the combination of transition and lanthanide metals in its structure provides a feasible pathway to design new large SHG oxysulfides.
基于结构中灵活的阴离子（S/O）比例，开发了一种多种阴离子（S和O）组合的方法，作为探索具有可调性质的新型优异非线性光学（NLO）氧硫化物的有效手段。需要注意的是，同时含有碱土金属（Ae）和三价镧系金属（Ln）的混合镁黄长石型氧硫化物呈现出天然的非中心对称（NCS）和无序结构，展现出良好的NLO性质。在此，我们引入低配位的ZnS来取代La基镁黄长石中高配位的AeS，从而打破初始的无序结构，导致形成具有有序结构的LaZnGaSO NLO材料。性能研究表明，LaZnGaSO实现了良好平衡的NLO行为，具有宽光学带隙（3.0 eV）和超强的相位匹配二次谐波产生（SHG）响应（1.9×AgGaS）。在镁黄长石型过渡金属氧硫化物中，LaZnGaSO表现出最大的粉末SHG响应，基于SHG密度分析，这归因于LaSO、ZnS和GaSO阴离子基团的协同贡献。这表明LaZnGaSO是频率转换应用中潜在的NLO候选材料，其结构中过渡金属和镧系金属的组合为设计新型大SHG氧硫化物提供了一条可行的途径。
