一维异质结构光电极的制备及其光电转换性能的研究

发布时间：2018-06-07 00:04

本文选题：太阳电池 + 半导体光电材料　；参考：《辽宁大学》2017年硕士论文

【摘要】：随着经济和科技的迅速发展,传统能源的快速消耗,环境也遭受到了相应的破坏,开发新型的绿色能源成为当前的一个重要目标。地表的太阳能具有环保、安全、寿命长和利用范围广等优势,因此太阳能是我们急需开发和利用的清洁能源并且有望成为人类最大的目标能源。半导体光电材料可作为利用太阳能的载体实现光电转换。ZnO和TiO2因具有来源广、成本低、电子迁移率高和光活性高等显著优点成为了研究最多的半导体光电材料,然而由于它们带隙较宽,主要吸收紫外光,不能有效利用可见光,导致基于ZnO和TiO2太阳电池的光电转换效率较低,它们在现实应用中就会受到某种程度的限制。因此,我们可以用窄带隙的半导体材料修饰ZnO和TiO2构筑纳米级别的异质结构或用有机染料敏化ZnO和TiO2构成复合体系,这样能够充分利用占太阳光谱中主要部分的可见光并且提高光电极在可见光下的光电转换效率。本文设计并合成了一维Fe2O3/TiO2和BiOI/TiO2/ZnO复合光电极,通过光电流技术、光伏技术以及平带电位的测试研究了材料的光电转换性能,探讨了光生电荷的传输机制,具体研究工作包括:1.用水热合成法在氟掺杂的二氧化锡(FTO)导电玻璃基底上分别制备了TiO2纳米棒阵列、Fe2O3纳米薄膜以及一维Fe2O3/TiO2纳米复合光电极,通过调节Fe2O3的量来选择该复合光电极的最佳光电性能。主要通过X-ray粉末衍射(XRD )、场发射扫描电镜(FESEM )、透射电镜(TEM )以及紫外可见漫反射光谱对材料的形貌进行分析。在模拟太阳光照射下进行光电流-时间、光电流-光伏和水氧化等实验,进而研究光电极的光电转换性能。通过对比测试得出,基于Fe203/Ti02太阳电池的光电转换效率达到0.2086% ,短路电流达到1.84 mA/cm2 ,开路电压为0.44 V ,证明Fe2O3/TiO2光电极具有最佳的光电性能。根据平带电位的测试以及能带结构研究了光生电荷传输机理。2.用水热合成法分别在FTO导电玻璃基底上制备了 ZnO纳米棒阵列和TiO2纳米棒阵列,然后用化学沉积的方法在ZnO纳米棒上制备TiO2/ZnO纳米棒阵列最后再用化学沉积的方法对以上三个样品进行BiOI敏化制得BiOI/ZnO和BiOI/TiO2和BiOI/TiO2/ZnO光电极。通过XRD、FESEM和紫外可见漫反射光谱对以上六个样品进行形貌分析,在模拟太阳光下进行光电流、光伏和水氧化的测试。通过对比六个电极的测试结果得出,基于BiOI/TiO2/ZnO太阳电池的光电转换效率最高,达到0.3173% ,短路电流达到2.788 mA/cm2 ,证明BiOI/TiO2/ZnO光电极具有较好的光电转换性能。水氧化的实验结果显示了BiOI/TiO2光电极的起始电压最低,BiOI/TiO2/ZnO光电极的光电流最高,进一步证明BiOI/TiO2/ZnO具有优越的光电性能。根据平带电位初步探讨了光电效应理论。
[Abstract]:With the rapid development of economy and science and technology and the rapid consumption of traditional energy, the environment has been destroyed accordingly. Therefore, the development of new green energy has become an important goal at present. Surface solar energy has the advantages of environmental protection, safety, long life and wide range of use. Therefore, solar energy is a clean energy that we need to develop and use urgently, and is expected to become the largest target energy of mankind. Semiconductor optoelectronic materials can be used as carriers of solar energy to realize photoelectric conversion. ZnO and TiO2 have become the most studied semiconductor optoelectronic materials because of their wide source, low cost, high electron mobility and high photoactivity. However, because of their wide band gap, which mainly absorbs ultraviolet light and can not utilize visible light effectively, the photoelectric conversion efficiency based on ZnO and TiO2 solar cells is low, and they will be limited to some extent in practical applications. Therefore, we can use narrow band gap semiconductor materials to modify ZnO and TiO2 to construct nanoscale heterostructures or to use organic dyes to sensitize ZnO and TiO2 to form composite systems. In this way, the visible light, which is the main part of the solar spectrum, can be fully utilized and the photoelectric conversion efficiency of the photoelectrode under the visible light can be improved. In this paper, one-dimensional Fe2O3/TiO2 and BiOI/TiO2/ZnO composite photoelectrodes are designed and synthesized. The photoelectric conversion properties of the materials are studied by photocurrent technology, photovoltaic technology and flat band potential measurement, and the mechanism of photocharge transmission is discussed. The detailed research work includes: 1. TiO2 nanorod array Fe _ 2O _ 3 nanocrystalline film and one-dimensional Fe2O3/TiO2 nano-composite photoelectrode were prepared on fluorine-doped tin dioxide (FTO) conductive glass substrate by hydrothermal synthesis. The optimum optoelectronic properties of the composite photoelectrode were selected by adjusting the amount of Fe2O3. The morphologies of the materials were analyzed by X-ray powder diffraction, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and UV-Vis diffuse reflectance spectroscopy (UV-Vis). The photocurrent-time photocurrent-photovoltaic and water oxidation experiments were carried out under simulated solar irradiation to study the photoelectric conversion performance of the photoelectrode. The results show that the photoelectric conversion efficiency is 0.2086%, the short circuit current is 1.84 mA/cm2 and the open circuit voltage is 0.44 V based on the Fe203/Ti02 solar cell. It is proved that the Fe2O3/TiO2 photoelectrode has the best photoelectric performance. Based on the measurement of flat band potential and the energy band structure, the photoinduced charge transport mechanism was studied. ZnO nanorod arrays and TiO2 nanorods arrays were prepared on FTO conductive glass substrates by hydrothermal synthesis. Then the TiO2/ZnO nanorod arrays were prepared on ZnO nanorods by chemical deposition. Then the three samples were sensitized with BiOI by chemical deposition to obtain BiOI/ZnO BiOI/TiO2 and BiOI/TiO2/ZnO photoelectrodes. The morphologies of the above six samples were analyzed by means of XRDX FESEM and UV-Vis diffuse reflectance spectroscopy. Photocurrent photovoltaic and water oxidation measurements were carried out under simulated sunlight. Compared with the test results of six electrodes, the photovoltaic conversion efficiency of the solar cell based on BiOI/TiO2/ZnO is the highest, up to 0.3173%, and the short-circuit current is 2.788 mA/cm2. It is proved that the BiOI/TiO2/ZnO photoelectrode has better photoelectric conversion performance. The experimental results of water oxidation show that the initial voltage of BiOI/TiO2 photoelectrode is the lowest and the photocurrent of BiOI/TiO2/ZnO photoelectrode is the highest. It is further proved that BiOI/TiO2/ZnO has superior photoelectric performance. The theory of photoelectric effect is preliminarily discussed according to the flat band potential.
【学位授予单位】：辽宁大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O646.5

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