【作者】 韩坤；

【导师】 杨柏；

【作者基本信息】 吉林大学 ， 高分子化学与物理， 2006， 博士

【摘要】 具有优异的光电性能的II-VI族半导体材料,在光电转换,光致发光,生物标记,传感等领域都有着极其诱人的前景。但由于半导体材料在环境稳定性及生物相亲性等方面存在缺陷,人们便借助各种物理和化学方法来解决这一问题。其中通过与其他介质的复合是一个重要的途径,而针对这些复合结构的研究才刚刚起步。这些问题的解决无论在理论上研究胶体的界面性质还是在实际的应用中都显得十分重要。本论文采用不同的方法来实现半导体材料和化学稳定的二氧化硅材料的复合与杂化,并最终实现材料的多功能化。主要包括四方面的工作:第一我们利用简单的溶胶-凝胶法成功地制备出了窄分散的CdTe-SiO2杂化微球,我们发展的这一方法最大的优点在于水相的CdTe纳米晶不需要任何的修饰,而得到的杂化微球不但很好地保持了纳米晶的发光性质,而且其尺寸也可以在相当大的尺寸范围内可调。第二,我们提出一种新的制备CdTe-silica复合纳米粒子的方法,在该方法中纳米晶的表面的巯基羧酸配体与含有环氧官能团的硅烷偶联剂反应并进一步实现了在纳米晶表面生成非常薄的二氧化硅壳层。第三,我们对另一种重要的半导体材料ZnO与二氧化硅的复合进行了研究并通过非常简单易行的方法制得了ZnO/SiO2核壳胶体微粒或核壳膜层材料,并进一步通过刻蚀除去核层的ZnO部分得到中空的二氧化硅微粒或膜层。第四,结合文献工作和我们的实验结果,我们提出了关于II-VI族半导体材料与二氧化硅之间都具有着非常好的界面相容性的推测,并进一步选取了两种II-VI族半导体材料来证实这一推测。在理论分析上,我们探讨了胶体间的“界面相容性”就是相似相容这一原理在胶体界面间的一个具体反映,这一结论的得出为构造更为复杂和多样的杂化材料提供了理论上的指导和技术上的支持。更多还原

【Abstract】 Due to outstanding photo-electronic properties, II-VI semiconductormaterials have shown great prospect in optoelectronic conversion, sensor,luminescence and biological imaging. It is necessary to fabricatesemiconductor-inert materials because of stability and consistency ofsemiconductor materials reacting with organism. Base on this idea, we try toprepare II-VI semiconductor-silica composites and have prepared CdTe-SiO2doped composite microspheres, core-shell composite nanoparticles and films. First, based on prepared high quality CdTe nanocrystals aqueous, we havesynthesized monodisperse, doped CdTe-SiO₂ composite microspheres by a facileand prevalent method. Without any modifying or altering, the CdTe nanocrystalscan be incorporated into SiO₂ matrix by sol-gel method in St?ber system. Thismethod changing the idea that the nanocrystals have to be modified by silaneligands with thio or amido group before introducing into silica, moreover, themethod has simplified the process. The composite microspheres can be controlledfrom 150 nm to 1.4 μm in diameter. We have prepared four kinds of CdTenanocrystals with different stabilizers and it is found that MPA molecular is thebest stabilizers for synthesizing CdTe-SiO2 composites. Because of the protectingof silica matrix, the nanocrystals in composite microspheres are more stable tosurroundings changing than the CdTe in solution. The mechanism of reaction hasalso been invested and more kinds of composites are expected to be synthesizedwith this method. The CdTe-SiO2 composite microspheres can be used as buildingblock to prepare photonic crystals in future.In order to prepare CdTe-silica composite nanoparticles, the nanocrystalshave been coated with a thin silica film by grafting silane ligands with epoxy, atthe same time, the nanocrystals bave been dissolved in ethanol. The CdTe-silicacomposite nanoparticles can be modified with functional group by grafting silaneligands in ethanol. The functional CdTe-silica nanoprticles will show more effectin biological imaging, et al.We have also synthesized composite colloid particles with silica and animportant semiconductor-ZnO, and the ZnO/SiO2 core/shell composite particlesor films have been obtained. ZnO microparticles or film have been proved to becoated with silica directly by a sol-gel method, the ZnO need not any pretreatmentand the thickness of silica shell are controllable. We have coated three kinds ofdifferent ZnO particles and one kind ZnO thin film with silica shell, respectively.Without doubt, the stable silica shell on ZnO particles or films will help ZnOextend its application in more fields. When the ZnO cores are etched, silicahollow microparticles or hollow film are obtained. These hollow particles or filmwill show potential application in drug releasing and micro-reaction room.In order to study the consistence of II-VI semiconductor and silica, we haveextended more II-VI materials to be coated with silica. Based on synthesizing ofZnO/SiO2 core/shell particles and films successfully, HgO, CdS and CdCO3（precursor of CdO） microparticles have also been coated with silica directly bythe same method. We make a presupposition about the interface consistence ofII-VI semiconductor materials and silica based on our experiment result andreference: II-VI semiconductor materials can all be coated with silica directly by asimple sol-gel method because of good interface consistence between them. Webelieve that the interface consistence is the idiographic embodiment of “similitudeis compatible”. This presupposition provides theoretical direction of synthesizingmore composites of II-VI semiconductor materials and silica, moreover, thecomposites can help II-VI semiconductor materials show more effect inoptoelectronic fields.更多还原