纳米结构氧化锌的可控制备及其光伏性能研究

发布时间：2018-05-06 01:41

  本文选题：氧化锌 + 纳米阵列　； 参考：《西南交通大学》2014年博士论文

【摘要】：能源与环境的可持续发展是社会发展和人类文明的两大重要战略。随着人类对化石资源的不断消耗和对能源需求的日益增加,使得人们对清洁新能源的开发越来越重视。其中,太阳能具有资源丰富、分布广泛、绿色环保等特点,被认为是最具潜力的新能源之一。染料敏化太阳能电池(Dye-sensitized Solar Cells, DSSC)具有制作工艺简单和成本低廉等优点,因而具有良好的发展前景。纳米结构光阳极薄膜是DSSC的重要组成部分,其结构与组成直接影响电池的光伏性能,因此如何优化与设计光阳极结构是近年来DSSC领域研究的热点问题之一。本文针对优化和设计光阳极薄膜结构的关键问题,以ZnO微/纳结构材料为研究对象,通过水热法控制合成ZnO纳米阵列及ZnO多级纳米阵列结构,探讨了ZnO纳米结构的可控生长机制,系统研究了ZnO纳米结构对DSSC光电转换性能的影响规律。本文的具体工作和主要研究结果包括：1.通过水热法制备了ZnO纳米草阵列结构,研究了添加剂对ZnO纳米草形貌、尺寸、长径比的影响规律。结果表明,延长水热生长时间,ZnO纳米棒的直径和长度都呈增大趋势；进一步研究发现,向生长溶液中添加非极性聚乙烯亚胺(Polyethyleneimine, PEI)可以调控ZnO纳米结构的形貌和长径比：当PEI浓度由0增加至7 mM,ZnO纳米棒尖端形貌由六棱柱状逐渐转变为锥体状,长径比由34.34提高至93.83。此外,本文的研究还发现,Al3+也可以调控ZnO纳米结构的生长,向生长液中添加少量硝酸铝(0.25 mM), ZnO纳米棒的直径由465 nm显著地降低至210 nm；进一步增加硝酸铝浓度时,ZnO纳米棒的直径没有明显的变化。作者分析认为,ZnO晶核的晶面选择性吸附添加剂是调控ZnO纳米结构生长的主要原因。2.采用柠檬酸三钠辅助晶体二次生长,在ZnO纳米棒表面原位生长ZnO纳米片,制备了ZnO纳米棒-纳米片(ZnO NR-NS)多级纳米阵列结构,发展了基于柠檬酸三钠辅助ZnO异相成核原位制备ZnO多级纳米阵列结构新方法。表征结果表明,ZnO纳米棒表面均匀包覆ZnO纳米片,ZnO纳米片由纳米颗粒定向排列而成；同时,二次生长的温度对ZnO NR-NS多级纳米阵列结构具有重要影响。在此基础上,成功地将柠檬酸三钠辅助二次生长技术拓展至柔性金属基体(锌片、不锈钢网),制备出ZnO NR-NS多级纳米阵列结构。3.利用不同长径比的ZnO纳米草、ZnO NR-NS多级纳米阵列以及柔性基体ZnONR-NS多级纳米阵列制备了DSSC,并系统比较了其光伏性能。研究发现：用长径比大的ZnO纳米草制备的DSSC具有更高的短路电流密度和光电转换效率,其短路电流密度由1.93提高至2.90 mA·cm-2,光电转换效率由0.47%提高至0.73%,其原因是大的长径比具有更高比表面积能够吸附更多的染料；比较了利用ZnO纳米草与ZnO NR-NS多级纳米阵列所制备DSSC的光伏性能,发现后者的光电转换效率提高了近70%,由0.66%提高至1.13%,其原因在于ZnO NR-NS多级纳米阵列结构光阳极进一步提高了染料的负载量,同时还具有较高的光散射能力；基于柔性锌片ZnO NR-NS多级纳米阵列DSSC的光伏性能结果也表明,ZnO NR-NS多级纳米阵列有利于提高光电转换效率。4.通过柠檬酸三钠辅助水热生长技术制备了微米棒、多维结构微球和空心微球等ZnO低维结构,研究了基于不同形貌ZnO微/纳结构的DSSC光伏性能。系统研究结果表明：引入柠檬酸根离子能够改变ZnO晶核的本征生长方向,由原来的[001]晶向变为[100]晶向择优生长；当柠檬酸根离子浓度为1 mM时,得到直径为2-3 gm的ZnO多维结构微球,其形成机理经历了ZnO纳米颗粒的定向自组装形成纳米片,ZnO纳米片再自组装形成多维微球结构；当柠檬酸根离子浓度为4 mM时,形成直径为2-4 μm的ZnO空心微球,其生长过程则是先形成ZnO实心微球,经历Ostwald熟化过程演变成空心微球。研究了基于三种ZnO微/纳结构的DSSC光伏性能,结果表明ZnO多维结构微球的光电转换效率达到1.42%,明显高于ZnO微米棒和空心微球的光电转换效率(分别为0.41%和0.79%),分析认为这是多维结构微球内部高的染料负载量、优异的光散射能力以及较长的电子寿命共同作用的结果。5.采用浸渍法制备了导电聚苯胺(PANi)杂化ZnO纳米草结构,并研究了PANi杂化ZnO纳米草对光伏性能的影响。经FT-IR和Raman光谱证实PANi和ZnO之间存在类化学键的杂化作用；当PANi的浓度为100 mg·L-1时,经PANi杂化后的ZnO纳米草电极的光电转换效率提高了60%,由0.40%升高至0.64%。研究还发现,PANi与ZnO之间的杂化作用能够有效促进光生电子在界面的分离,这是杂化电极光电转换效率提高的重要原因。
[Abstract]:The sustainable development of energy and environment is the two important strategy of social development and human civilization. With the continuous consumption of fossil resources and the increasing demand for energy, people pay more and more attention to the development of clean energy. Among them, the solar energy is rich in resources, widely distributed, green and environmental protection, and is considered as a kind of characteristics. One of the most potential new energy sources. The Dye-sensitized Solar Cells (DSSC) has the advantages of simple process and low cost, so it has good prospects. The nanostructured photo anode film is an important part of DSSC. Its structure and composition directly affect the photovoltaic performance of the battery, so how to optimize the photovoltaic performance of the battery. In recent years, the design of the structure of the photo anode is one of the hot issues in the DSSC field. In this paper, the key problem of optimizing and designing the structure of the photo anode film is to control the synthesis of the ZnO nanowire array and the ZnO multistage nanoarray structure by the hydrothermal method. The controllable growth machine of the ZnO nanostructure is discussed. The effect of ZnO nanostructures on the photoelectric conversion performance of DSSC was systematically studied. The specific work and main results of this paper were as follows: 1. the structure of ZnO nanograss array was prepared by hydrothermal method, and the influence of additives on the morphology, size and length diameter ratio of ZnO nanoscale was studied. The results showed that the time of hydrothermal growth was prolonged, ZnO nanorods were prolonged. The diameter and length are all increasing, and further study shows that the addition of non polar polyethyleneimine (Polyethyleneimine, PEI) to the growth solution can regulate the morphology and length to diameter ratio of ZnO nanostructures: when the PEI concentration increases from 0 to 7 mM, the tip morphology of ZnO nanorods gradually transforms from six prism to cones, and the ratio of length to diameter is raised by 34.34. In addition to 93.83., the study also found that Al3+ could also regulate the growth of ZnO nanostructures, adding a small amount of aluminum nitrate (0.25 mM) into the growth liquid, and the diameter of ZnO nanorods decreased significantly from 465 nm to 210 nm, and there was no significant change in the diameter of ZnO nanorods when the concentration of aluminum nitrate was further increased. The crystal surface selective adsorption additive is the main reason for the regulation of the growth of ZnO nanostructures..2. uses sodium citrate three to grow the crystal two times, and the ZnO nanorods on the surface of ZnO nanorods are grown in situ. The ZnO nanorod nanoscale (ZnO NR-NS) multistage nanoarray structure is prepared, and the presence of sodium citrate three sodium is used to assist ZnO heterogenous nucleation in situ. A new ZnO multistage nanoarray structure was prepared. The results showed that the surface of the ZnO nanorods was uniformly coated with ZnO nanoscale, and the ZnO nanoscale was arranged by the nanoparticles. At the same time, the temperature of the two growth was important to the structure of ZnO NR-NS multilevel nanoscale arrays. On this basis, the sodium citrate three sodium was successfully assisted by two times. The technology is extended to the flexible metal matrix (zinc sheet, stainless steel mesh), and the ZnO NR-NS multistage nanoarray structure.3. is prepared by using different length to diameter ratio of ZnO nanoscale, ZnO NR-NS multistage nanoscale arrays and flexible matrix ZnONR-NS multilevel nanoscale arrays, and its photovoltaic performance is compared systematically. The study shows that the length to diameter ratio of ZnO nanometers is large. The DSSC prepared by grass has higher short circuit current density and photoelectric conversion efficiency. The short circuit current density is increased from 1.93 to 2.90 mA. Cm-2, and the photoelectric conversion efficiency is increased from 0.47% to 0.73%. The reason is that the larger diameter ratio is higher than the surface area and can adsorb more dyes; compared with the use of ZnO nanoscale and ZnO NR-NS multilevel nanoscale array It is found that the photovoltaic performance of DSSC is improved by nearly 70%, from 0.66% to 1.13%. The reason is that the ZnO NR-NS multi-stage nanoarray photoanode further improves the load of the dye, and also has high light scattering ability; based on the flexible zinc chip ZnO NR-NS multistage nanoscale array DSSC The performance results also show that the ZnO NR-NS multistage nanoarray is beneficial to the improvement of the photoelectric conversion efficiency (.4.) through the ZnO low dimensional structure, such as micron rods, multidimensional structure microspheres and hollow microspheres, through the technology of sodium citrate three sodium assisted hydrothermal growth. The research results of the DSSC photovoltaic performance based on the different morphology of ZnO micro / nano structures have been studied. Citric acid ions can change the intrinsic growth direction of ZnO nucleation, and grow from the original [001] crystal to [100] crystal. When the concentration of citric acid ion is 1 mM, the ZnO multidimensional microspheres with a diameter of 2-3 GM are obtained. The formation mechanism experienced the directional self-assembly of ZnO nanoparticles and the formation of nanoscale fragments and the self-assembly of ZnO nanoscale. A multi-dimensional microsphere structure was formed. When the concentration of citric acid ion was 4 mM, the ZnO hollow microspheres with a diameter of 2-4 m were formed. The growth process was first formed by the formation of ZnO solid microspheres, which evolved into hollow microspheres through the process of Ostwald ripening. The photovoltaic properties based on three ZnO micro / nano structures were studied. The results showed that the photoelectric microspheres of ZnO multidimensional structure were optoelectronic. The conversion efficiency is 1.42%, obviously higher than the photoelectric conversion efficiency of ZnO micron rods and hollow microspheres (0.41% and 0.79% respectively). It is considered that this is the high dye load in the multidimensional structure microspheres, the excellent light scattering ability and the longer electron life effect..5. is prepared by the impregnation method to prepare the conductive polyaniline (PANi) hybrid. The structure of ZnO nano grass and the effect of PANi hybrid ZnO nano grass on the photovoltaic performance were investigated. FT-IR and Raman spectra confirmed the presence of chemical bonds between PANi and ZnO. When PANi concentration was 100 mg L-1, the photoelectric conversion efficiency of ZnO nanoscale electrode after PANi hybrid increased by 60%, from 0.40% to the study. Now, the hybridization between PANi and ZnO can effectively promote the separation of photoelectrons in the interface, which is an important reason for the improvement of photoelectric conversion efficiency of hybrid electrodes.

【学位授予单位】：西南交通大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM914.4;TB383.1

【参考文献】

相关博士学位论文 前1条

1 李政道;基于微/纳结构Zn、Sn基氧化物的染料敏化太阳能电池光阳极制备、性能研究[D];南京大学;2013年

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