利用化合反应设计合成新颖非线性光学晶体化合物及其性能研究

Nonlinear Optical (NLO) materials are able to convert the laser wavelength and are widely used in many laser technology-related fields, such as communication, medical treatment, and space antimissile fields. But the current materials surfer their own intrinsic drawbacks and cannot satisfy the increasing application demands. Therefore, exploration of novel NLO material system with high performance is a hot topic and a great challenge in this field. Our previous work revealed that the “combination reaction” drives a desired structural transformation from centrosymmetric Ba8Ga2Sn7Se18 to noncentrosymmetric Ba10Ga2Sn9Se22 with well-maintained chain structural details. We thus named such a reaction “noncentrosymmetric combination reaction”. Based on these knowledge, this proposal is aimed to systematically study the novel NLO compounds in A/M/Sn/Q，A/Ga/Sn(M)/Q systems (A is alkali metals, alkali earth metals), focusing on the syntheses, crystal structures, coordination modes, bonding motifs and electron density distributions so as to uncover the micro mechanism driving such a centro-to-noncentrosymmetric structural transformation, and to establish the concept of “noncentrosymmetric combination reaction”. We hope these understandings will shed useful insight on the future study on high performance NLO materials. We anticipate to discover 1 novel NLO compounds with excellent performance in the mid- and far-IR region; publish at least 2 papers with JACS and Angew. Chem level and apply for 2-3 patents.

非线性光学（NLO）晶体材料能实现激光频率转换，在通讯、医疗、空间反导等领域得到广泛应用。发现高效NLO材料体系是该领域的热点和难点。我们前期工作发现新型的“无心加成反应”促成在结构特征保持不变的情况下，一维链结构从有心向无心的结构转变，生成无心化合物Ba10Ga2Sn9Se22。基于此，本项目将系统开展低维阴离子体系的“无心加成反应”研究，探索新颖A/M/Sn/Q，A/Ga/Sn(M)/Q化合物。以所得化合物为研究对象，开展配位模式、成键形式或电子云变形性等研究，发现有心-无心结构转变的微观机制，建立并完善“无心加成反应”概念。为新颖NLO材料的结构调控、设计合成研究提供新思路。本项目预期获得性能指标达到国际领先水平的新颖中远红外NLO化合物1种；发表2篇以上如JACS等的论文，申请发明专利2-3件。

本项目致力于新颖红外非线性光学化合物的探索合成、设计合成、及红外非线性光学性能提升的研究。开展了A/M/Sn/Q，A/Ga/Sn(M)/Q等体系新颖化合物的探索研究。提出结构匹配度调控策略实现商用AGS材料性能大幅提升、首次用实例证明非公度调制结构对NLO性能的增强作用等创新学术成果。发表标注文章12篇，其中美国化学会志1篇，德国应用化学2篇。培养了2名博士毕业，3名硕士毕业。其中1名硕士获评2019年北京市优秀毕业生。.（1）.首次用实例证明非公度调制结构对非线性光学性能的显著增强 .发现首例具有非公度调制结构的红外非线性光学化合物A2SnS5（A = Ba, Sr），相位匹配倍频强度为AgGaS2的1.1倍，激光损伤阈值为AgGaS2的8倍。由于非公度调制的作用，结构中Sn/S阴离子基团的畸变程度比没有调制结构，或只有一个方向调制结构的情况分别增大了44%和25%，因此显著增强了二阶倍频响应。（Angew. Chem. Int. Ed. 2020, 59, 11861—11865.）.（2）.结构匹配度调控策略实现商用AGS材料性能大幅提升.发现系列化合物LixAg1-xGaS2(0 < x <1.0)，单晶结构研究表明：Li掺杂能在很大的组分范围内（0-0.6）保持AGS四方晶体结构高对称性，这打破了长期以来的常规认识。其中Li0.60Ag0.40GaS2的性能研究表明，该材料透过截止边达到365 nm（比AGS的截止边缩短了180 nm）、大幅拓宽了AGS材料的应用波段范围；同时其激光损伤阈值得到大幅提升，达AGS的8.60倍，倍频效应强度能达到AGS的1.10倍。展现了良好的应用前景，尤其是有望解决AGS激光损伤阈值低，器件寿命短等问题。（Angew. Chem. Int. Ed. 2019, 58, 9979−9983.）