导　　师： 白玉白;李铁津

学科专业： G0304

授予学位： 博士

作　　者： ;

机构地区： 吉林大学

摘　　要： 半导体量子点正向人们展示着其独特的性质魅力，并拥有着广阔而深远的应用背景，吸引了众多科学工作者积极投入到这一研究领域中。CDTE作为一种重要的半导体量子点材料，被我们选作研究对象。本论文系统研究了CDTE量子点的制备、组装、复合与初步的应用。具体内容如下： 首先在水相合成了高发光的巯基乙酸包覆的CDTE量子点，讨论了各种反应条件对CDTE生长速度、发光性质的影响。利用CDTE具有较大的偶极矩这一特性，通过部分除去量子点表面有机配体，实现了CDTE量子点的一维组装，制备了CDTE纳米线。并在此基础上，用巯基乙酸和半胱氨酸两种混合配体，首次可控生长了高质量的水溶性CDTE纳米棒。 开创性地用金纳米粒子作为种子，构建了CDTE纳米晶的球形组装体，并探讨了这种结构形成的机制。通过与通常条件下制备的CDTE量子点相比较，发现了其与结构相关的特殊的光谱性质，提出了纳米晶“离域激子态”的概念。 系统研究了CDTE量子点与无机SIO2的复合。分别在水相和乙二醇相制备了CDTE/SIO2复合物，并对它们的性质进行了具体研究。还利用静电相互作用，对CDTE量子点和SIO2纳米粒子进行组装，制备了SIO2/CDTE核壳结构微球材料。 首次将CDTE量子点与温敏性高分子PNIPAM的复合，制备了高发光的CDTE/PMIPAM水凝胶，实现了水溶性CDTE量子点材料向体相材料的转变，将量子点和PNIPAM两种材料的特性融为一体，可能发展成为一种特殊的多功能材料。实验结果证实，CDTE/PNIPAM水凝胶的发光对外界温度变化非常敏感。 此外，还对CDTE材料的应用进行了一些初步研究，探讨了CDTE量子点作为荧光探针用于乙肝疾病免疫层析检测的可能应用；首次将CDTE量子点与纳米棒用于二价金属阳离子的定性和定量分析。 Recently, colloidal luminescent semiconductor nanocrystals are of great interest for both fundamental research and technical applications, due to their unique properties. Colloidal luminescent semiconductor nanocrystals have several inherent functional advantages compared to organic dyes. The photoluminescence /(PL/) emissions of high-quality semiconductor nanocrystals are narrow, symmetric, and strongly size-dependent. The absorption spectra of nanocrystals with different sizes all extend from the onset to deep UV. These spectral features make it possible to carry out multiple labeling with a single-laser setup. Core//shell nanocrystals formed by growing a lattice-matched, higher band gap material on the top of the core are quite stable against photo-oxidation. With the recent developments in synthetic chemistry, nearly monodisperse, highly luminescent semiconductor plain core and core//shell nanocrystals covering an entire optical window could be prepared at low cost with so-called greener approaches. All thos e features have attracted tremendous interest in exploring novel materials based on semiconductor nanocrystals. CdTe was chosen because it was a representative example of the important luminescent semiconductor nanocrystals that has been used in numerous applications, such as in light-emitting devices, photoelectrochemical cells, photonic and biological labels. My dissertation is focused on the preparation, assembly, composite and primary application of luminescent CdTe nanocrystals. Now many novel results are obtained from our experiments. The main results are outlined as followings. /(1/) Preparation of CdTe quantum dots /(QDs/), nanowires and nanorods. Control of luminescent properties and shape of nanocrystals has been playing a critical role in this very active field. The thioglycolic acid /(TGA/)-capped CdTe QDs were prepared using the reaction between Cd/(ClO4/)2 6H2O and NaHTe in aqueous solution. The effects on luminescent properties of CdTe QDs were studied under a serial of reaction conditions, such as the change of pH value, the amount of TGA added, the ratio of reaction precursor /(Cd2+ to Te2'/) in detail. The relative optimal conditions were found for synthesis of different sized CdTe QDs. The CdTe QDs prepared as above were spontaneously organized into luminescent CdTe nanowires. One of the key steps in the preparation of nanowires from nanoparticles was the partial removal of stabilizer. The permanent dipole moment of CdTe is the driving force. Based on this result, the dipole moment of semiconductor and the chelate function between the amino acid ligands and ions of transition elements were utilized in the strategy for achieving CdTe nanorods. To the best of our knowledge, this is the first report of synthesis of highly luminescent water-soluble CdTe nanorods. HREM image has shown that the /(200/) plane of cubic crystal lattice was the predominant growth orientation. The aspect ratio and the PL peak of CdTe nanorods could be easily controlled by the refluxing time. /(2/) Fabrication of unique structure and photoluminescence of Au//CdTe nanostructure materials Now building and patterning of semiconductors nanocrystals into two- and three- dimensional organized and designed structures is an important goal in materials chemistry for the application of the ordered system in electronic, sensor, and photonic devices. CdTe QDs were self-organized into spherical aggregates using Au as seeds. The formation mechanism is considered to be a cooperative effect of dipole-dipole interaction and the nanocrystals growth in the given reaction environment. 'Abnormal' red shift of the photoluminescence peak of the spherical aggregates was observed. The unique structure is related to their 'abnormal' photoluminescence. In the spherical aggregates, the distance between each CdTe nanocrystals is very small, and there is strong dipole-dipole interaction between the CdTe nanocrystals, which leads to the formation of so-called exciton states, which are delocalized over several CdTe nanocrystals. /(3/) Incorporation of lum

关 键 词： 发光 纳米晶 制备工艺 量子点

分 类 号： [O649]

领　　域： [理学] [理学]