基于ZnO量子点的异质结构可控制备和光学性质研究

发布时间：2017-12-28 21:12

  本文关键词：基于ZnO量子点的异质结构可控制备和光学性质研究　出处：《南昌航空大学》2016年硕士论文　论文类型：学位论文

  更多相关文章： CdS/ZnO异质结构 ZnS/ZnO异质结构 CuS花状结构 光学特性 光催化 电化学

【摘要】：半导体异质结构纳米材料在光探测、光催化和太阳能电池等方面具有广泛的、潜在的应用。本文主要在两种不同的纳米带上生长ZnO量子点,构成异质结构,并研究了异质结构的光学特性。另外,CuS是一种重要的II-VI族半导体材料,在储能器件等方面有潜在应用,本文采用水热发成功合成了CuS微米花结构,采用电化学方法研究了基于CuS超级电容的充放电性能,为其在超级电容器方面的应用奠定基础。主要研究内容和结论如下:(1)CdS/ZnO异质结构及其光学性质研究。首先采用热蒸发法制备基底CdS纳米带,接着以CdS纳米带为基底,采用热分解乙酸锌溶液的方法成功制备了CdS/ZnO一维异质结构。通过乙酸锌浓度、热分解温度以及反应时间等参数的优化,有效地控制在纳米带表面生长ZnO电子点的尺寸和分布。通过XRD,FESEM和TEM等测试,探索得到了影响ZnO量子点尺寸和分布的最佳生长条件。室温PL光谱测试结果表明:CdS/ZnO异质结构在508.95nm和699.69nm处有两个发光带,分别对应于本征发射和缺陷发射。与CdS纳米带的光致发光谱相比,发生了明显的红移现象,且本征发射峰明显增强,而缺陷发射峰在逐渐减弱。拉曼光谱测试表明,CdS/ZnO异质结构两个频移峰中心位于299.11cm-1和601.97cm-1,与CdS纳米带相比,其峰位向低波数方向发生了移动,即发生了红移现象。(2)CdS/ZnO异质结构光催化性能研究。通过降解10mg/L的罗丹明B溶液研究了CdS/ZnO异质结构的光催化性能。当在紫外可见光下照射35min时,CdS/ZnO异质结构一定浓度的罗丹明B溶液的两次降解率分别为97.62%和92.18%,与CdS纳米带对相同浓度的罗丹明B溶液的降解率90.94%和82.01%相比,光催化效率明显提高,且光腐蚀现象降低。这说明Zn O量子点扩展了纳米带的光响应范围,并且通过半导体复合,CdS激发产生的光生电子能有效地转移到ZnO的导带,从而实现光生电子空穴对的有效分离,提高了光催化活性。(3)ZnS/ZnO异质结构及其光学性质研究。采用相同方法,在ZnS纳米带表面成功生长ZnO量子点,构成ZnS/ZnO异质结构。借助于XRD,EDS,FESEM及TEM测试技术对样品的形貌和结构进行表征分析。研究了ZnS/ZnO异质结构的光学性能。研究结果表明:采用乙酸锌热分解的方法,可以有效地实现在不同半导体纳米带上生长ZnO量子点,控制量子点的分布和尺寸。(4)利用水热法,以硝酸铜和硫脲为原材料,成功合成了CuS花状结构。通过FESEM观察其形貌,分析了其生长机制。发现CuS花状结构是由纳米片聚集而形成,粒径约为2um,分布均匀。通过循环伏安法,循环稳定性测试以及交流阻抗谱的测试研究了CuS电极的电化学性能。当扫描速率为5mv/s时,CuS电极的比电容为170.948F/g,相比于文献报道的基于CuS的电容器,本文具有更高的比电容和循环稳定性。
[Abstract]:Semiconductor heterostructure nanomaterials have a wide range of potential applications in light detection, photocatalysis and solar cells. In this paper, ZnO quantum dots are grown on two different nanoscale bands to form a heterostructure, and the optical properties of the heterostructures are studied. In addition, CuS is a kind of important II-VI semiconductor materials have potential applications in energy storage devices, the water heat synthesis of CuS micron flower structure, studied the charge discharge performance of CuS based on super capacitor by electrochemical method, lay the foundation for its application in the super capacitor. The main contents and conclusions are as follows: (1) the study of CdS/ZnO heterostructure and its optical properties. First, the substrate CdS nanobelts were prepared by thermal evaporation. Then, the one-dimensional heterostructure of CdS/ZnO was successfully prepared by thermal decomposition of zinc acetate solution on the basis of CdS nanobelts. By optimizing the concentration of zinc acetate, thermal decomposition temperature and reaction time, the size and distribution of ZnO electron points on the surface of nanoscale have been effectively controlled. The optimum growth conditions for the size and distribution of ZnO quantum dots were investigated by XRD, FESEM and TEM tests. The room temperature PL spectra test results show that the CdS/ZnO heterostructures have two luminescent bands at 508.95nm and 699.69nm, which correspond to the intrinsic emission and the defect emission respectively. With the CdS nanobelts photoluminescence spectra compared to red shift phenomenon, and then the peaks increased significantly, but the defect emission peak gradually weakened. Raman spectra show that CdS/ZnO heterostructure two frequency peak centered at 299.11cm-1 and 601.97cm-1, compared with CdS nanobelts, shifted the peak wave number direction, namely red shift phenomenon. (2) study on the photocatalytic properties of CdS/ZnO heterostructure. The photocatalytic properties of CdS/ZnO heterostructures were studied by Luo Danming B solution degrading 10mg/L. When in the ultraviolet and visible light irradiation 35min, the degradation rate of B solution two times Luo Danming CdS/ZnO heterostructure concentrations were 97.62% and 92.18%, Luo Danming on the same concentration of B solution and CdS nanobelts degradation rate of 90.94% and 82.01% compared to the photocatalytic efficiency is improved obviously, and reduce the corrosion phenomenon of light. This indicates that Zn O quantum dots extend the optical response range of nanobelts, and the photogenerated electrons generated by CdS excitation can be effectively transferred to ZnO conduction band through semiconductor recombination, so as to effectively separate the photoelectron hole pairs and enhance the photocatalytic activity. (3) the study of ZnS/ZnO heterostructure and its optical properties. Using the same method, the ZnO quantum dots were successfully grown on the surface of the ZnS nanoscale, and the ZnS/ZnO heterostructure was formed. The morphology and structure of the samples were characterized by XRD, EDS, FESEM and TEM. The optical properties of ZnS/ZnO heterostructures are studied. The results show that the thermal decomposition of zinc acetate can effectively achieve the growth of ZnO quantum dots on different semiconductor nanobelts and control the distribution and size of quantum dots. (4) by hydrothermal method, using copper nitrate and thiourea as raw materials, synthesis of CuS flower like structure. The morphology was observed by FESEM and its growth mechanism was analyzed. It is found that the flower structure of CuS is formed by the aggregation of nanoscale, and the particle size is about 2um, and the distribution is uniform. The electrochemical performance of the CuS electrode was studied by cyclic voltammetry, cyclic stability test and AC impedance spectroscopy. When the scanning rate is 5mv/s, the specific capacitance of CuS electrode is 170.948F/g. Compared with the CuS based capacitor reported in the literature, this paper has higher specific capacitance and cycle stability.
【学位授予单位】：南昌航空大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O471.1;TB383.1

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