孤对电子立体化学活性对氧酸盐体系大倍频效应的响应机理研究

Nonlinear optical (NLO) materials with high second harmonic generation (SHG) frequency conversion efficiency is the key materials for laser technology field, especially, the related research has become one crucial project in the national development plan of space laser technology. However, high second harmonic generation frequency conversion efficiency needs a rigorous condition: (1) large SHG response; (2) high laser damage threshold which strongly depends on the band gap in crystal, usually wide band gaps are not benefit for large NLO effect. Based on our previous experience in the design and synthesis of NLO borates Pb2Ba3(BO3)3Cl, Bi3OF3(IO3)4 with large SHG responses about 3-6 times of KH2PO4(KDP), the project will further focus on lone electronic pair metal borates (carbonates, etc.) to carry out the following research: to characterize the intensity of stereochemically active lone electronic pair (SCALP), and analyze how the interaction between the cations and the anionic groups affects the activity of SCALP; to identify the electronic states correlated to SHG response, clarify the direct and indirect contributions from SCALP, and reveal the origin of large SHG response; to explore the strategy on how to balance the contradiction between large SHG responses and wide band gaps, predict and synthesize materials utilized in the NLO field, 3-5 new compounds are expected by the material screening method; 1 new crystal with UV cutoff<250 nm is expected. The project will offer new NLO materials for space laser technology, the method studied will improve the traditional exploration mode of new materials and give references for structure prediction and material screening; the improvement of platform will also benefit the talent-development during the project.

高激光倍频转换效率非线性光学材料是激光技术的核心材料，特别是国家在空间激光等领域的重要发展方向。高激光倍频转换效率要求具备“大倍频效应-宽带隙”相消关系苛刻条件，课题组前期通过引入含孤对电子阳离子获倍频效应达3-6倍于磷酸二氢钾的Pb2Ba3(BO3)3Cl、Bi3OF3(IO3)4等，在此基础上，本项目拟以含孤对电子阳离子氧酸盐为研究目标，通过解决含孤对电子阳离子立体化学活性程度标示等问题，分析阳离子-阴离子耦合作用对立体化学活性影响机制；表征出与倍频效应关联的电子态，阐明含孤对电子阳离子引入所产生直接和间接贡献响应机理，揭示大倍频效应内在规律；提出平衡大倍频-宽带隙相消关系的研究策略，进行新结构预测及筛选并指导制备材料；筛选3-5种新化合物，制备1种满足条件非线性光学晶体。该项目实施为空间激光等领域提供材料基础；为改善材料直线式研发模式提供技术支撑；为区域科技发展和人才建设提供平台。

高激光倍频转换效率非线性光学材料是激光技术的核心材料，特别是国家在空间激光等领域的重要发展方向。本项目以含孤对电子阳离子氧酸盐为研究目标，发展了含孤对电子阳离子立体化学活性程度标示分析方法，分析Pb-O、Bi-O、Sb-S等阳离子-阴离子耦合作用对立体化学活性影响机制；表征出与倍频效应关联的电子态，阐明含孤对电子阳离子引入所产生直接和间接贡献响应机理，揭示大倍频效应内在规律；设计了Pb-O-X（X=卤素）、PbB4O6F2、K2Na(IO3)2(I3O)等新材料。在该项目支持下，相关成果申请中国发明专利2项，相关成果发表3篇Chem. Mater.（影响因子=9.8）、2篇Sci. China. Mater.（影响因子=8.2）、1篇Phys. Rev. Lett. (影响因子=9.1)等材料、物理类著名SCI期刊上19篇，其中作为第一、第二标注SCI论文为11篇；培养硕博士研究生4名。