【作者】 范海；

【导师】 钱逸泰；

【作者基本信息】 中国科学技术大学 ， 无机化学， 2008， 博士

【摘要】 本论文旨在探索和研究微尺度（微米～纳米）硒碲化合物半导体材料、结构控制合成以及特殊新颖形貌制备的新方法、新路线。以水热、溶剂热技术为基础,发展了一种以乙醇胺为基础的化学液相反应体系。我们以金属硒碲化合物半导体为例,通过改变实验条件,如原料摩尔比、溶剂体积比、表面活性剂浓度等,可以对产物的结构、物相及形貌进行有效的控制。论文主要内容归纳如下:1.发展了溶剂热合成技术,在乙醇胺—水混合溶剂体系中,控制合成了不同结构和形貌的CdSe纳米晶。通过控制乙醇胺/水的体积比,成功的控制得到了六方、立方相的CdSe以及它们的混合相。通过控制乙醇胺/水的体积比,还可以有效控制产物的形貌。2.设计出乙醇胺—聚乙二醇反应体系,在此体系中,合成了CdSe纳米棒构成的微米管。实验表明,乙醇胺/水的体积比,聚乙二醇的加入量对产物的形貌有很大的影响。根据实验结果,我们提出了以聚乙二醇形成的棒状胶束作为软模板,制备CdSe微米管的可能形成机理。3.设计出乙醇胺—聚乙烯醇反应体系,控制合成了不同物相和形貌的各种硒化镍微米晶体。系统研究了不同反应条件对产物物相和形貌的影响。通过控制原料Ni（Ac）₂·7H₂O和SeO₂的摩尔比从1:3变化到3:1,我们可以依次得到NiSe₂,NiSe₂和NiSe,NiSe,NiSe和Ni₃Se₂,不同物相的硒化镍晶体材料。通过控制聚乙烯醇的加入量,可以有效控制合成不同形貌的晶体。4.设计出乙醇胺—葡萄糖反应体系,控制合成了不同形貌的硫属化合物（Bi₂Se₃,CoTe）纳米材料,研究了不同反应条件对产物形貌的影响,并提出了可能的反应机理。（1）以Bi（NO₃）₃·5H₂O和SeO₂为原料,在上述体系中制备了花状Bi₂Se₃纳米晶。实验发现花状Bi₂Se₃纳米晶是由花状Se纳米晶为模板原位生成的。所制备的花状Bi₂Se₃纳米晶保持了模板的形貌。（2）我们在相同的反应体系中,以CoSO₄·7H₂O替换Bi（NO₃）₃·5H₂O,TeO₂替换SeO₂,制备了CoTe纳米管。实验发现,反应初期会生成Te纳米棒,随着反应时间的延长,在Te纳米棒的表面会生成CoTe纳米颗粒层,当反应时间增加到16小时时,即可得到CoTe纳米管。根据对反应过程的研究,我们提出了碲纳米棒原位模板法,生长CoTe纳米管的生长机理。5.设计出一种可逆化学反应的方法来制备Se晶体。实验发现,MnCl₂·4H₂O可以作为碱性中和剂,通过加入不同浓度的MnCl₂溶液,可有效改变反应溶液的碱性强度,从而控制Se晶核的初始生成浓度,进一步得到不同形貌的Se晶体（Se微米棒束、微米管和片状枝晶）。更多还原

【Abstract】 The goal of this dissertation is to explore and study novel synthetic methods and routes to synthesize semiconductor metal selenides and tellurides micro and nano-scale materials with controlled structures and various novel morphologies. Based on the hydrothermal and solvothermal technique,we developed an ethanolamine based reaction system in this thesis.Taking metal selenides and tellurides as example,by adjusting the reaction parameters,such as the molar ratio of raw materials,the volume ratio of solvents,the concentration of surfactants and so on,the crystal structure and the morphology of the products can be effectively controlled.The main contents can be summarized as follows:1.An ethanolamine and water mixed solution route was developed for the synthesis of CdSe nanocrystallines with controllable phase and morphology.The phase transition of CdSe nanocrystallines from zinc blende to wurtzite phase can be controlled by varying the volume ratio of ethanolamine and water in their mixed solution,and the morphologies of the CdSe nanocrystals are controlled simultaneously.2.A reaction solution made of ethanolamine and polyethylene glycol-20000 （PEG）was developed to synthesis of CdSe nanorod-assembled microtubes. Experiment revealed that both the solvent ethanolamine and surfactant PEG-20000 played a key role in the formation of nanorod-assembled microtubes.According to the experimental results,a possible formation mechanism was proposed using PEG micelle rods as soft templates to prepare CdSe nanorod-assembled microtubes.3.A reaction solution made of ethanolamine and Polyvinyl Alcohol（PVA）was proposed to synthesis of nickel selenides crystals with tunable phase and morphology. It was found that the phase of the products could be controlled by adjusting the Ni/Se ratio of the raw materials.With the ratio of Ni/Se increase from 1:3 to 3:1, NiSe₂,NiSe₂ and NiSe,NiSe,NiSe and Ni₃Se₂ can be successively obtained. Furthermore,by controlling the quantity of PVA added in the reaction,the products with different morphologies could be obtained.4.A reaction solution made of ethanolamine and glucose was proposed to controlled synthesis of metal chalcogenides（such as Bi₂Se₃ and CoTe）with different morphologies.The morphologies of the products could be greatly adjusted by varying the experimental parameters.Based on the above results,the possible mechanisms were proposed.（1）Using Bi（NO₃）₃·5H₂O and SeO₂ as raw materials, flower-like Bi₂Se₃ nanocrystals were prepared in the ethanolamine and glucose reaction solution.It was found that flower-like Bi₂Se₃ nanocrystals were formed based on the flower-like Se nanocrystals.The prepared flower-like Bi₂Se₃ nanocrystals kept the original morphology of flower-like Se nanocrystals.（2）In the same reaction solution,using COSO₄·7H₂O instead of Bi（NO₃）₃·5H₂O and TeO₂ instead of SeO₂,we prepared CoTe nanotubes.The experiment indicated that Te nanorods could be formed in the intermediate reaction process.With the reaction time prolonged,CoTe nanoparticles layers could be formed based on the Te nanorods,finally,CoTe nanotubes could be formed after the reaction time prolonged to 16 h.Based on the above results,an in-situ template-directed synthesis process was proposed to prepare CoTe nanotubes.5.A simple reversible chemical reacting process under hydrothermal conditions was proposed to grow t-Se crystals.By controlling the concentration of MnCl₂·4H₂O, the alkaline strength of the solution was controlled,and the initial concentration of the Se nuclei was controlled simultaneously.As a result,t-Se aligned microrod bundles,microtubes and dendrites could be obtained.更多还原