【作者】 徐永斌；

【导师】 任忠鸣；

【作者基本信息】 上海大学 ， 钢铁冶金， 2010， 博士

【摘要】 纳米材料的调控合成是纳米科技发展的重要组成部分,是研究纳米结构性能及其应用的基础。本论文围绕Bi属半导体纳米材料的液相调控合成进行研究,探讨了外加强磁场作用于抗磁性物质生长习性的影响;利用单源前驱体手段,调控合成了晶形可控的Bi2S3纳米晶和Sb2S3微米晶,考察了产物性能与尺寸和形状的依互性关系;通过模板法辅助合成,获得大量Bi2Te3纳米片,研究其晶体二维生长特性与晶体结构的内在联系;此外,还发展了低温湿化学合成Bi2Te3基n/p位掺杂固溶体技术,合成结晶性较好的Bi2(Te,Se)3和(Bi,Sb)2Te3纳米晶。论文主要内容归纳如下:1.强磁场诱导Bi纳米结构的生长。通过将强磁场引入反应体系,诱导Bi纳米结构的一维生长,考察了不同合成条件对产物形貌的影响。并进一步将该思路拓展到一维Te微米结构的合成上。从晶体学的角度出发,理论研究磁场作用非磁性低维体系材料的一维生长效应。结果显示,磁场通过延缓反应的进程,对生长晶面进行修饰,诱导纳米材料基元的一维生长。2.单源前驱体调控合成Bi2S3纳米结构。从单源前驱体出发,表面剂辅助调控合成Bi2S3纳米棒,通过IR谱图研究表面剂对Bi2S3生长基元的动力学调控作用。并以此为基础提出无模板调控合成手段,合成形貌可控的Bi2S3纳米结构。研究发现,溶剂的包覆效应作用于晶体的生长过程,调控产物生长形貌的变化。进一步的,将该思路拓展到形貌可控Sb2S3微米结构的合成上。合成得到的Bi2S3纳米晶具有宽化的带隙宽度。Bi2S3纳米晶和Sb2S3微米晶的荧光性能显示具有典型的形状依互关系。3.模板法调控合成Bi2Te3纳米片。利用表面剂辅助水热、溶剂热法调控合成形貌均一的Bi2Te3纳米片。研究表明,Bi2Te3内部复杂键合结构作用于晶体生长过程中的裂解,而表面剂分子(PVP, CTAB)对生长晶面的吸附和解吸附,作用于裂解晶面,动态调控晶体生长过程,获得沿垂直于c轴方向生长的Bi2Te3纳米片。进一步的,人为构造层状结构,利用混合溶剂作用反应过程,大规模合成Bi2Te3纳米片。层状前驱体的引入,首次在酸性条件下合成纯物相的Bi2Te3纳米晶。推翻了仅能在碱性体系中合成Bi2Te3晶体的认识。4.低温湿化学合成Bi2Te3基n/p位掺杂固溶体。利用低温湿化学手段,大规模合成结晶性较好的Bi2(Te,Se)3和(Bi,Sb)2Te3纳米晶。结果表明, Se位掺杂作用于晶体结构的层间解理,诱导晶体沿垂直于c轴方向生长,获得二维Bi2(Te,Se)3纳米晶。而Sb位掺杂并没有改变晶胞中的键合作用,对产物形貌没有影响。进一步的,反应过程中Sb源的选择是合成(Bi,Sb)2Te3固溶体的关键。更多还原

【Abstract】 Controlled synthesis of nanomaterials is one of the most important sections of nanoscience and nanotechnology, and also the base to investigate the distinctive properties and applications of nanostructures. This thesis studied solution-based controlled synthesis of Bi-related semiconductor nanomaterials, emphasizing on the effect of high magnetic field on the growth of diamagnetic materials, controlled synthesis of Bi2S3 nanocrystals and Sb2S3 microcrystals via a single precursor route, the relationship between the properties and size/shape of the nanocrystals, manipulated growth of Bi2Te3 nanoplates by surfactant assisted route, the dependent connection between crystal structure and the two dimensional (2D) growth trade and the controlled growth of Bi2(Te,Se)3 and (Bi,Sb)2Te3 solid solution through a simple aqueous chemical method at low temperature. The major contents of this dissertation are epitomized as follows:1. High magnetic field induced growth of Bi nanostructures. With the introduction of high magnetic field, one dimensional Bi nanostructure could be obtained. The effect of synthetic conditions on the shape of the nanocrystals was studied. Furthermore, the synthetic notion was extended to the growth of Te microrods. Besides, the effect of magnetic field on the one dimensional (1D) growth of diamagnetic materials was discussed. The results showed that when the magnetic field was introduced, the reaction process was slowed down, the crystal face was modified and the 1D growth trade was induced.2. Controlled synthesis of Bi2S3 nanocrystals via a single precursor route. With the help of surfactant, monodisperse Bi2S3 nanorods were obtained. Based on the IR observation, the effect of surfactant on the growth nucleus was discussed. Furthermore, a simple single precursor route without surfactant was issued, and the Bi2S3 nanocrystals with controlled shapes could be synthesized. The solvent effect held an important role during the crystal growth, which would induce the shape changes. Moreover, the novel idea was extended to the growth of Sb2S3 microrods with controllable shapes. The results showed that the band gap of Bi2S3 nanocrystals was larger than that in bulk materials. The PL performance of Bi2S3 nanocrystals and Sb2S3 microcrystals showed typical shape dependence.3. Manipulated growth of Bi2Te3 nanoplates by surfactant assisted route. Under the condition of surfactant assisted hydrothermal or solvothermal route, large amount of Bi2Te3 nanoplates were obtained. It showed that the crystal structure could act on the split process during the crystal growth. The surfactant molecules (PVP, CTAB) could adsorb to the crystal face, manipulate the growth process. The Bi2Te3 nanoplates with the growth direction perpendicular to c axis could be synthesized. Furthermore, an artificial lamellar structure has been adopted during the growth of Bi2Te3 nanoplates. With the help of lamellar precursor, pure Bi2Te3 nanocrystals could be prepared in an acidic reaction system, and the cognition that Bi2Te3 should be synthesized in an alkaline reaction system was overthrown.4. Controlled growth of Bi2(Te,Se)3 and Bi2(Te,Se)3 through a simple aqueous chemical method at low temperature. Large amount of Bi2(Te,Se)3 and (Bi,Sb)2Te3 nanocrystals could be synthesized via a chemical route. It showed that once Se doped into the lattice, it held the effect on the crystal split process, induced the two dimensional (2D) growth trade, and 2D Bi2(Te,Se)3 nanocrystals could be finally obtained. While Sb doped into the lattice, it did not show this effect. Furthermore, the Sb source is the key to synthesize pure Bi2(Te,Se)3 solid solution更多还原