【作者】 陈观娇；

【导师】 钟新华；

【作者基本信息】 华东理工大学 ， 应用化学， 2011， 硕士

【摘要】 近年来科学界发展了多种具有优异性能的复合纳米晶(主要包括合金纳米晶、核／壳结构纳米晶、掺杂纳米晶)。而当今的科研趋势是向着环境友好型,成本节约型,操作简易型的方向发展。半导体纳米晶的制备技术在逐渐成熟的过程中,也与主流趋势同步,逐渐的向着采用无毒的低成本的化合物的方向发展。本文采用不同的方法合成了高质量的核/壳结构的CdSe/CdS/ZnS纳米晶和掺杂纳米晶Mn:ZnS。CdSe/CdS/ZnS纳米晶中CdSe核的制备过程没有涉及烷基磷(如三辛基膦,TOP)之类的昂贵的高毒性的物质,而是直接采用硒粉作为硒源合成了闪锌矿结构CdSe核。CdSe核上的CdS和ZnS壳层的生长过程采用普通商用的单分子前驱物CDC(二乙基二硫代氨基甲酸镉)和ZDC(二乙基二硫代氨基甲酸锌),代替了以往作为前驱物的有毒的有机金属物质,比如双(三甲基硫化硅)和二乙基锌。在实验操作更简单的同时,制备的CdSe/CdS/ZnS半导体纳米晶具有很高的荧光量子产率(有机相中高达90%,以及通过MPA配体交换转移至水相后仍高达60%。掺杂纳米晶Mn：ZnS的制备采用了成核掺杂的方法。制备的Mn：ZnS纳米晶的荧光量子产率达到了54%。实验结果表明制备尺寸尽可能小的MnS核是实验成功的关键因素。通过采用配位能力相对较弱的十二硫醇作配体、合适的反应温度以及合适的Mn：S比例可以控制MnS核的尺寸,从而实现增强锰的发射峰强度的目的。并且通过研究光谱特性的变化推断了CdSe/CdS/ZnS纳米晶和掺杂纳米晶Mn：ZnS形成的机理,以及通过TEM、XRD等测试方法对产物的结构进行了表征。更多还原

【Abstract】 Recent years, the scientific community has developed a variety of semiconductor nanocrystals with excellent performance (including alloy nanocrystals, core/shell structure nanocrystals, doped nanocrystals). However, the current research trend is toward the direction of environmentally friendly, cost savings, operating simple. As the synthesis technology of semiconductor nanocrystals is becoming mature, the mainstream trend is gradually toward the use of low-cost and non-toxic compounds.With different methods we synthesize core/shell structured nanocrystals CdSe/CdS/ZnS and doped nanocrystals Mn:ZnS. The preparation of CdSe core does not involve highly toxic and expensive substances such as alkylphosphine (TOP, etc.) which is used as solvent in most approaches. During the CdS and ZnS shell growth process on the CdSe core, a kind of common commercial single molecule precursor CDC(cadmium diethyl dithiocarbamate) and ZDC(zinc diethyl dithiocarbamate)are used instead of the toxic organic metals, such as bis(trimethylsilyl)sulfide and diethyl zinc. In the experiment, not only operation is more simplely, but also the fluorescence quantum yield of CdSe/CdS/ZnS nanocrystals is high (up to 90% in organic phase, and up to 60% in the water phase through the MPA ligand exchange). Doped nanocrystals Mn:ZnS is prepared by nucleation-doping method. The fluorescence quantum yield of Mn:ZnS nanocrystals is up to 54%. The results show that prepareing the smallest size of MnS nucleus is a critical factor. Through the use dodecanethiol as ligand which have the relatively weak coordination ability, a suitable reaction temperature and the right Mn:S ratio, we can control the size of MnS core. As a result, the Mn emission intensity can be enhanced. What’s more, by studying the spectral characteristics we inferred the formation mechanism of CdSe/CdS/ZnS and doped nanocrystals Mn:ZnS, and characterize the structure of the product by TEM, XRD and other testing methods.更多还原