【作者】 林映霞；

【导师】 曹立新；

【作者基本信息】 中国海洋大学 ， 环境科学， 2003， 硕士

【摘要】 纳米材料被誉为21世纪的材料，纳米发光材料在形态和性质上的特点使其在应用上有着体相材料不可比拟的优势，它将有助于纳米电子器件的发展。纳米微粒的限域效应有可能使材料的量子效率获得提高，但是随着粒子的减小，越来越多的原子处于表面层，而表面态大多对发光起猝灭作用。大量表面态的存在制约着纳米发光材料的发展，因此纳米发光材料走向实用，首当其冲的课题就是研究和控制表面态。 本文制备了核—壳结构的Cu²⁺掺杂的ZnS纳米粒子以及普通的没有壳的Cu²⁺掺杂的ZnS纳米粒子，并且研究了ZnS无机壳层对ZnS：Cu纳米粒子发光性质的影响，目的在于用简单的方法得到核—壳结构的Cu²⁺掺杂的ZnS纳米粒子，了解掺杂纳米材料的发光过程和表面态对能量传递的影响，为设计高效的、高亮度的纳米发光材料提供一些理论上的参考。 本工作的主要内容和结果如下：： 1、采用胶束方法制备了核—壳结构的Cu²⁺掺杂的ZnS纳米粒子以及普通的没有壳的Cu²⁺掺杂的ZnS纳米粒子，对制备二者的最有效的条件进行了研究，结果发现，溶液的pH=7～8；[Zn²⁺]：[多聚磷酸钠]≈2：1时，若[Zn²⁺]≈5×10^-4mol／L，[Zn²⁺]：[Cu²⁺]=300：1，则普通的没有壳的Cu²⁺掺杂的ZnS纳米粒子发光效果较好；在符合上述条件情况下，同时满足[Zn²⁺]核：[Zn²⁺]壳=1：1的条件，则制得的核—壳结构的Cu²⁺掺杂的ZnS纳米粒子发光效果最好。 2、对核—壳结构的Cu²⁺掺杂的ZnS纳米粒子光学性质的研究表明：随着ZnS壳层的增厚，激发光谱红移，发射光谱也红移，调节其厚度可以得到最强的发射位置在470nm左右。完整的、适当厚度的ZnS壳层可以很好的钝化粒子表面，减少无辐射复合中心的数目，提高荧光发射强度。 3、对核—壳结构的Cu²⁺掺杂的ZnS纳米粒子以及普通的没有壳的Cu²⁺掺杂的ZnS纳米粒子的光学性质进行了对比研究，结果发现，粒径相同，Cu²⁺掺杂浓度也相同的核—壳结构的ZnS：Cu纳米粒子在470nm左右的发光大约是普通的没有壳的Cu²⁺掺杂的ZnS纳米粒子发光的2.5倍。说明，ZnS壳层对纳米粒子表核一壳结构的zns:cu纳米粒子的制备及表面修饰对对其发光性质的影响面起到了修饰作用，增大了c矿+到纳米粒子表面的无辐射复合中心的距离，堵塞了某些无辐射跃迁的通道，从而增强了47Otun左右的发光。 4、通过对粒径大小影响的研究和对c矿十掺杂方式不同的研究，发现采用置换方式做核，可以使C矿+更好的进入zns的晶格，增大cu2+发光的比例。更多还原

【Abstract】 With different properties from their bulk materials, semiconductor nanomaterials have drawn considerable interests. As a new type of luminescent materials, there are two key factors determining their optical proerties. Quantum confinement effect may result in the quantum yield raising, but the surface states usually act as radiationless recombination centers. Researching and controlling the effect of surface states on the luminescence of nanoparticles were important for the application of luminescent nanomaterials. So the surface modification of nanoparticles which could passivate the surface becomes an active research field.In this paper, core-shell ZnS: Cu nanoparticles and common ZnS: Cu nanoparticles were prepared in colloid ways, and the effect of the shell which was a layer of ZnS on ZnS: Cu nanoparticles was studied, The purpose of the paper is to study the luminescent progresses of nanocrystals and to provide some theoreticals and experimental bases for establishing modle of energy transfer and its practical application. The important results which were obtained in the paper were list as following:It was studied that the luminescence of ZnS: Cu nanoparticles was good at the condition following: pH = 7~8; [Zn2+]: [Na5P3Oio] 2: 1, [Zn2+] ^5 X l(T4mol/L, [Zn2+]: [Cu2+] = 300: 1. The core-shell ZnS: Cu nanoparticles has best luminescence at the station: [Zn2+]core: [Zn2+]shell = 1 : 1.Studies of the core-shell ZnS: Cu nanoparticles indicated that the maximum luminescence in the region of about 470nm can be obtained by tuning the thickness of ZnS shell. The complete ZnS shell which had an appropriate thickness could enhance the lunminescence of the nanoparticles. If the thickness of ZnS shell further increased, the luminescence at 470nm reduced. These results indicated that ZnS shell made all the Cu2+ ionsoccupy the sites in the nanoparticles, increasing the distance of Cu2+ ions to the surface, blocking a good number of nonradiative relaxation paths, leading to the enhancement of the lunminescence at 470nm. But when the thickness of ZnS shell further increased, the concentration of Cu2+ in the ZnS nanoparticles would discrease, which may result in the reducing of the luminescence.更多还原