一维ZnO@ZnS核壳结构纳米材料的制备及其性能研究

发布时间：2018-01-11 13:00

  本文关键词：一维ZnO@ZnS核壳结构纳米材料的制备及其性能研究　出处：《东南大学》2017年硕士论文　论文类型：学位论文

  更多相关文章： 一维纳米材料 半导体材料 光催化剂

【摘要】：近年来直接带隙宽禁带半导体ZnO被广泛研究,较大带隙(3.37eV)和较高激子复合能(60meV)使得ZnO成为较为适合做蓝、紫外光电设备的材料之一。其独特的物理化学特性,使其在很多领域都有应用潜力,如传感器,场效应管,太阳能电池电极,纳米发电机等。垂直对齐的ZnO纳米线阵列,由于其特殊的一维结构和独特的性能而被广泛研究。在实际应用中,通过控制生长条件来合成形态和质量良好的纳米线是提高应用器件性能的关键。当ZnO和ZnS结合为ZnO@ZnS核壳结构的纳米线阵列时,ZnS作为功能层处于ZnO核和外界环境中间,这将极大的改变ZnO核的性能。因此,ZnO@ZnS核壳结构的纳米线阵列已经被报道对于器件性能的改善有很大的作用,比如,较好的光致发光,提高染料敏华太阳能电池的效率等。本文的主要工作如下:(1)利用微波辅助水溶液化学法在FTO玻璃衬底上制备了氧化锌纳米线阵列,通过自制的连续滴加溶液装置,实现了在较短时间内生长出超长的ZnO纳米线阵列。研究表明随着反应时间的增加,ZnO纳米线阵列的长度呈线性增加。通过对比不同种类的锌盐作为反应原料合成的ZnO纳米线阵列的形貌和长径比,发现采用醋酸锌作为锌源所合成的ZnO纳米线阵列生长速度较快,底部融合较少。因此醋酸锌是短时间内合成超长的ZnO纳米线阵列的理想锌源。(2)采用醋酸锌作为锌源所生长的ZnO纳米线阵列结晶性良好,密度适中。对该纳米线阵列进行光催化测试,发现随着纳米线长度的增加,其对甲基橙染料的降解速率增加。原因可总结为以下两点:一、我们所合成的纳米线具有独特的一维结构,为其光生电子的传输提供了良好的通道,利于光生电子-空穴的分离,进而提高了样品的催化效果。二、该ZnO纳米线具有较大的比表面积,为其污染物的附着提供了广阔的面积,从而提高了 ZnO纳米线的光催化效果。(3)在成功制备了一维ZnO纳米线的基础上,采用气相硫化法将ZnO表面一层硫化为ZnS,从而得到了 ZnO@ZnS核壳结构纳米线阵列,该样品仍然结晶性良好、排列整齐。通过控制硫化时间的长短,可以调控纳米线表面ZnS层的厚度。并且其光催化效果优于单纯的ZnO纳米线阵列,对于今后纳米复合材料在污水净化研究中的研究提供了实验依据。
[Abstract]:In recent years, direct bandgap wide band gap semiconductor (ZnO) has been widely studied. The larger band gap (3.37 EV) and the higher exciton compound energy (60 MEV) make ZnO more suitable for blue. Because of its unique physical and chemical properties, it has potential applications in many fields, such as sensors, field effect tubes, and solar cell electrodes. ZnO nanowire arrays with vertical alignment have been widely studied because of their special one-dimensional structure and unique properties. The key to improve the performance of application devices is to synthesize nanowires with good morphology and quality by controlling the growth conditions. When ZnO and ZnS are combined to form nanowire arrays with ZnO@ZnS core-shell structure. As a functional layer, ZnS is in the middle of the ZnO core and the external environment, which will greatly change the performance of the ZnO core. Nanowire arrays with ZnO@ZnS core-shell structure have been reported to have great effect on the improvement of device performance, for example, better photoluminescence. The main work of this paper is as follows: 1) ZnO nanowire arrays were prepared on FTO glass substrate by microwave-assisted aqueous solution chemistry. An ultra-long ZnO nanowire array was grown in a short time by a self-made continuous dripping device. The results show that the nanowire array grows with the increase of reaction time. The length of ZnO nanowire arrays increased linearly. The morphology and aspect ratio of ZnO nanowire arrays synthesized from different zinc salts were compared. It was found that the ZnO nanowire array synthesized by zinc acetate as a zinc source had a faster growth rate. Therefore zinc acetate is the ideal zinc source for the synthesis of ultra-long ZnO nanowire arrays in a short time.) the ZnO nanowire arrays grown by zinc acetate have good crystallinity. The photocatalytic test of the nanowire array shows that the degradation rate of methyl orange dyes increases with the increase of nanowire length. The reasons can be summarized as follows: 1. The synthesized nanowires have a unique one-dimensional structure, which provides a good channel for photoelectron transport, is conducive to the separation of photogenerated electrons and holes, and improves the catalytic effect of the samples. The ZnO nanowires have a large specific surface area, which provides a wide area for the adhesion of the pollutants. Therefore, the photocatalytic effect of ZnO nanowires was improved. On the basis of successfully preparing one-dimensional ZnO nanowires, the surface layer of ZnO was vulcanized to ZnS by gas phase vulcanization. The ZnO@ZnS core-shell nanowire arrays were obtained. The samples were still well crystallized and arranged neatly, and the curing time was controlled. It can control the thickness of ZnS layer on the surface of nanowires, and its photocatalytic effect is better than that of simple ZnO nanowire arrays, which provides an experimental basis for the future research of nanocomposites in wastewater purification.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36;TB383.1

【参考文献】

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