三维类金刚石网格硫属化合物的探索合成，晶体生长及非线性光学性能研究

Mid- and far- infrared (MFIR) nonlinear optical (NLO) materials are crucial in the modern MFIR laser frequency conversion technology that includes optoelectronic device, resource exploration, long-distance laser communication. But the current commercial IR NLO materials, including AgGaS2, AgGaSe2, and ZnGeP2 surfer their own intrinsic drawbacks, therefore, exploration of novel MFIR NLO material system with high performance is a hot topic and a great challenge in this field. Our previous work revealed that 1) chalcogenides with 3D diamond-like frameworks(DLFs) have shown functionalization based on the substitutional flexibility; 2) several chalcogenides with 3D DLFs we obtained have exhibited large second-harmonic generation (SHG) coefficient dij and high laser induced damage thresholds (LIDTs); 3) their band gaps and properties depend on the identity and stoichiometry of the cation and anion, which infer a possibility to obtain high performance MFIR NLO compounds. Based on these knowledge, this proposal is aimed to systematically study the R/M’/M/Q systems (R = cations; M’= transition /main group metals; M = group13 metals; Q = chalcogenides), based on the platform of 3D DLFs by adjusting the cation/anion identity and stoichiometry; focusing on their exploration syntheses, crystal grown and second-order NLO properties. And theoretical studies have aided the understanding of electronic structures and NLO performances and to summary the correlations of the crystal structure–NLO property relationship. We are hoping to discover several new outstanding MFIR NLO materials, and to shed useful insight on the future study on high performance NLO materials.

中远红外非线性光学(NLO)材料在光电对抗、资源探测、远距离通讯等方面有重要的应用。由于AgGaS2, AgGaSe2, ZnGeP2等商业化晶体仍然存在一些自身的缺点，因此探索合成性能优良的新颖中远红外NLO材料仍是该领域的研究热点和难点。我们前期工作发现：1）三维类金刚石网格结构硫属化合物具有很好的结构可调性；2）获得数例化合物均具有大的二阶倍频系数和高的激光损伤阈值；3）该类化合物的能隙和性能随离子种类和计量比可调，有望借此获得高性能的中远红外NLO材料。为此，本项目拟利用三维类金刚石网格结构作为调控平台，系统开展R/M’/M/Q化合物探索合成和晶体生长。对所得化合物的NLO性能进行研究，并通过理论研究阐明其具有优异性能的特殊结构原因，总结归纳结构与性能的构效关系。本项目有望发现若干性能优良的中远红外NLO材料，为新颖红外NLO材料的结构调控、设计合成研究提供新思路。

按照计划书，本项目提出的研究目标是：合成一系列三维类金刚石网格结构硫属化合物，并对其进行结构表征以及晶体生长，对得到的晶体材料的红外非线性光学性能进行系统研究，总结归纳结构与性能的构效关系。同时也探索了一些具有非中心对称结构的硫属材料的红外非线性性能及相关的性能改性。本项目在国家自然科学基金面上项目(21771179)资助的四年中，按照拟定的计划开展相关的研究工作，较好的完成了项目计划书确定的研究任务和内容。设计合成了一系列具有三维类金刚石网格结构的硫属化合物，结合实验表征和理论计算对得到的晶体材料进行了相关非线性光学性能的研究。经过四年的努力，我们获得了一些有价值的研究成果，项目部分成果在Coord. Chem. Rev., Chem. Mater., Adv. Optical Mater., J. Mater. Chem. C, 等国际重要刊物上发表了26篇影响因子IF>4的论文，其中1篇入选ESI高被引（top 1%）论文以及3篇入选热点论文，出版专章1篇, 申请专利7项（授权2项），培养了3名硕士研究生。