基于二阶姜－泰勒效应的非中心对称磷酸盐功能晶体化合物的设计、合成、结构与性质

项目名称： 基于二阶姜－泰勒效应的非中心对称磷酸盐功能晶体化合物的设计、合成、结构与性质

项目编号： No.21271109

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 数理科学和化学

项目作者： 孙同庆

作者单位： 南开大学

项目金额： 80万元

中文摘要： 自倍频晶体是一种新型复合功能材料，其基质化合物须易于激活离子掺杂，且结构上必须非中心对称。六配位的d0电子组态的过渡金属阳离子和含有非成键孤对电子的阳离子易受二阶姜－泰勒效应影响导致氧多面体畸变，从而形成非中心对称的结构基元；因电价相同、半径接近，Bi3+作为晶体组分易于稀土激活离子掺杂。本申请运用晶体工程思想，以自倍频功能为导向，利用[PO4]3-基元可形成丰富多样结构骨干的特点，复合含孤对电子的Bi3+离子和d0电子组态的过渡金属阳离子M（Ti4+、V5+、Nb5+、Mo6+或W6+），合成新的非中心对称结构的磷酸盐化合物，以发展新的功能晶体材料。课题将探讨Bi－M－P－O体系的结晶化学规律、原子成键性质和各种氧配位多面体畸变对晶体结构、对称性的影响；测试与非中心对称相关的倍频、压电、热释电等功能性质，分析晶体结构和性能之间的影响关系；并考查Nd3+、Yb3+离子在化合中的发光特性。

中文关键词： 非中心对称；磷酸盐；晶体生长；倍频；构效关系

英文摘要： Self-frequency-doubling crystal is a new kind of multi-functional materials, and its host compounds must be easily doped by active ions and be non-centrosymmetric. Octahedrally coordinated d0 transition metals and cations with stereo-chemically active lone pairs are easily susceptible to second order Jahn-Teller effect and form asymmetric structure units. Compounds made up of Bi3+ ion are easily doped by the rare earth active ions for their same valence and similar ionic radii. From the view of inorganic crystal engineering, we will synthesis new phosphate compounds with acentric structures by combining the Bi3+ ion with stereo-chemically active lone pairs, octahedrally coordinated d0 transition metals M (including Ti4+、V5+、Nb5+、Mo6+ or W6+) with the diversified unusual structures formed by [PO4]3- polyhedra, and explore new functional materials for self-frequency-doubling. Characteristics of chemical bonds and influences of cations' distortions on structure and symmetry will be discussed. Functional properties (such as frequency doubling, piezoelectricity and pyroelectricity) will be measured and the relationship of structure and properties will be analyzed. Finally, luminescence properties of Nd3+ and Yb3+ ions in new compounds will be also studied.

英文关键词： Noncentrosymmetric；Phosphate；Crystal Growth；Second Harmonic Generation；Relationship of Structure and Properties