IV-VII族配合物型铁磁性半导体材料的合成与性能研究

Ferromagnetic semiconductor material formed by hybridizing organic semiconductor and molecular magnet is one of hot topics in material field. But the weak van der Waals interaction bonding between adjacent molecules of organic semiconductor makes carrier mobility of the material very low, which limits the response speed of device and therefore affects the application prospect of the material. This project will construct novel inorganic-organic hybrid ferromagnetic semiconductor material based on coordination compound by using inorganic compound semiconductor, which has high carrier mobility, as precursor. The inorganic part of such ferromagnetic semiconductor is the structural fragment of IV-VII compound MX2 (M = Sn, Pb; X = Cl, Br, I) semiconductor and the organic part is suitable organic ligand. The magnetic transition metal ion is introduced into such material during the structural regulation. Self-assembly of inorganic part, organic part and magnetic ion mainly through covalent bond gives rise to the target ferromagnetic semiconductor material at the molecular level. In this project, the structure and property will be characterized; the structural regulation law will be revealed; and by the help of theoretical calculation, the influences of magnetic metal ion and organic ligand on the electronic structure of M/X framework will be analyzed, and the mechanism on magnetic exchange interaction will be clarified, and the relation between the structure and property of material will be explicit; finally, the controllable preparation of ferromagnetic semiconductor material based on coordination compound, which has excellent optical, electrical and magnetic properties, will be achieved. This project will supply a brand new approach and theoretical support for the synthesis of new-style ferromagnetic semiconductor material.

杂化有机半导体和分子磁体形成铁磁性半导体材料是当前材料领域的研究热点之一,但由于有机半导体分子间弱的范德华力使得材料的载流子迁移率低，限制了器件的响应速度，因而影响了材料的应用前景。本课题提出基于具有高的载流子迁移率的无机化合物半导体构筑新颖的无机-有机杂化的配合物型铁磁性半导体材料。以IV-VII族化合物MX2（M = Sn，Pb；X = Cl，Br，I）半导体的结构碎片为无机组分，适当的有机配体为有机组分，结构调控的同时引入磁性过渡族金属离子，主要通过共价键合，在分子层次自组装形成配合物型铁磁性半导体材料。对材料进行结构表征和性能测试，揭示材料的结构调控规律，辅以理论计算，分析磁性离子及有机配体对M/X骨架的电子结构的影响，阐明磁交换机理，明晰材料结构与性能的关系，实现光电磁性能优异的配合物型铁磁性半导体材料的可控制备。本项目将为制备新型的铁磁性半导体材料提供一种崭新途径及理论支持。

本项目旨在以IV–VII族化合物MX2（M = Sn，Pb；X = Cl，Br，I）半导体的结构碎片为无机组分，适当的有机配体为有机组分，结构调控的同时引入磁性过渡族金属离子，主要通过共价键合，在分子层次自组装形成无机-有机杂化的配合物型铁磁性半导体材料。项目实施过程中，采用溶剂热法和溶液反应法，尝试了多样化的含氮、含氧、含硫和含磷的有机配体（如单齿、双齿和多齿配体，刚性和柔性配体，阴离子和中性配体）。研究成果如下：1）获得了含磁性金属离子Cu2+的配合物型半导体[Pb3I10Cu2(phen)4]n （phen = 邻菲罗啉）、[PbI5Cu(I)Cu(II)(phen)2(I2)0.5]n和[Pb2I6Cu(2,9-Me2-phen)]n。探讨了材料[Pb3I10Cu2(phen)4]n的结构与光电磁性能的关系，发现通过π–π堆积作用导致Cu2+间铁磁交换作用的产生，并结合理论计算，分析了磁性离子及有机配体对Pb/I骨架电子结构的影响。2）获得了含非磁性金属离子Cu+的异金属配合物型半导体材料，如[Pb3I8Cu2(bipy)2]n （bipy = 2,2'-联吡啶）、[PbI3Cu(2,9-Me2-phen)]n等。3）获得了以磁性金属离子Ni2+、Cu2+络合离子为模板的异金属半导体材料，如{[CuBr(phen)2][PbBr3]}n、{[Ni(bam)3][Pb2I6]}n （bam = 邻苯二胺）等。4）获得了以有机胺阳离子为模板的异金属半导体材料，如少见的3D {[debipy]2[Pb7Cu2I20]}n （debipy = N,N'-二乙基-2,2'-联吡啶）、2D {[debipy]2[PbCu6I12]}n等。5）研究了上述异金属半导体材料的合成条件、晶体结构及性能，丰富了此体系的结构，为制备新型的铁磁性半导体材料提供一种崭新途径及理论支持。