磷酸盐深紫外非线性光学材料的探索合成、晶体生长和性能研究

Deep-Ultraviolet (Deep-UV) nonlinear optical (NLO) crystals are applied as the key devices in many advanced scientific instruments. So far the sole NLO crystal that can produce the deep-UV coherent laser through direct second harmonic generation is the beryllium borate KBBF, but its commercial production and applications are heavily hindered by the highly toxic beryllium. Based on our previous studies, we propose that the phosphates possess the excellent capability of optical transparency in deep-UV region while not containing the toxic beryllium, so fully satisfy the requirements for deep-UV NLO applications. Therefore, phosphates are a new class of deep-UV NLO materials distinct from the conventional beryllium borates. In this project, we will use the molecular engineering search and design methods, including composition modulations, element substitutions and NLO-active group tailoring, to thoroughly explore new deep-UV NLO materials in the alkaline and alkaline-earth phosphate systems by further introducing halogen F- or engraft Si-O/S-O functional groups. At the same time, we will adopt the first-principles simulations to investigate the relationships between NLO properties and microscopic structures, such as compositions, atomic groups and their packing manners, in the deep-UV phosphate NLO materials. The structure-properties understandings can further help experiments to perform the materials search and design. It is expected that 1-2 new phosphates with good deep-UV NLO performance will be discovered. We will then perform the primary crystal growth for these materials, and study their fundamental physical and chemical properties. The successful fulfillment of this project may obtain new deep-UV NLO crystals that can break the commercial barrier of “200 nm wall”, and provide the material support to consolidate the leading role of China in this research field.

深紫外非线性光学（NLO）晶体是许多高端科学仪器的重要核心器件，但目前唯一可用的氟铍硼酸钾晶体存在含剧毒铍元素等问题，难以实现商业化。我们的前期研究发现：不含铍的磷酸盐，透光性能依然可满足深紫外NLO应用的需要，是一类有别于传统铍硼酸盐的新型深紫外NLO材料。本项目拟采用组分调控、元素取代、分子剪裁等晶体工程学手段，对碱金属和碱土金属磷酸盐体系进行深入探索，或进一步引入卤素F-或嫁接硅氧或硫氧功能基元，得到高性能的新型深紫外NLO材料；基于第一性原理的计算模拟，总结分析此类材料的NLO性能随组分、微观结构基元及其组装方式的变化规律，为其设计和可控制备提供科学依据；筛选出1-2种综合性能优秀的磷酸盐深紫外NLO材料，进行初步的晶体生长，并研究相关物化性能，为后续研究和应用奠定基础。本项目的顺利实施，有望获得可突破商业化壁垒的新型深紫外NLO晶体，为巩固我国在该领域的国际领先地位提供材料支撑。

深紫外非线性光学（NLO）晶体是许多高端科学仪器的重要核心器件，但目前唯一可用的氟铍硼酸钾晶体存在含剧毒铍元素等问题，难以实现商业化。不含铍的磷酸盐，透光性能依然可满足深紫外NLO应用的需要，是一类有别于传统铍硼酸盐的新型深紫外NLO材料。本项目采用晶体工程学手段，对碱金属和碱土金属磷酸盐体系进行了深入探索，合成了RbNaMgP2O7、CsNaMgP2O7、Cs2LiPO4、RbBPO4F、CsBPO4F、LiCs2Y2(PO4)3、CsLiCdP2O7等7种新型磷酸盐深紫外非线性光学晶体材料，获得了它们的单晶结构、紫外-可见漫反射光谱和粉末倍频效应等重要数据；基于第一性原理的计算模拟等手段，揭示了此类材料的NLO性能随组分、微观结构基元及其组装方式的变化规律新机制，为此类材料的设计和可控制备提供了科学依据；筛选出了RbNaMgP2O7、CsNaMgP2O7、Cs2LiPO4等综合性能优秀的磷酸盐深紫外NLO材料，进行了初步的晶体生长并获得了其大尺寸单晶，并初步研究了它们的生长工艺和相关物化性能，为后续研究和应用奠定了良好基础。同时，我们受到上述工作成果启发，在其它材料体系中成功获得了多种结构新颖、性能优异的新型非线性光学晶体材料。该项目有效推动了该领域相关研究进一步向前发展，并为巩固我国在该领域的国际领先地位提供了相关材料支撑。项目相关研究成果发表22篇SCI学术论文，1篇EI论文，其中IF>4的论文17篇，包括第一/通讯作者论文J. Am. Chem. Soc. 3篇、Angew. Chem. 1篇、Chem. Mater. 1篇，Coord. Chem. Rev. 2篇，另外，申请专利4项，获得授权3项，在项目执行期间培养培养硕士毕业生2名、博士毕业生2名。