【作者】 琚晓晖；

【导师】 封伟；

【作者基本信息】 天津大学 ， 材料学， 2009， 博士

【摘要】 氧化锌(ZnO)是一种宽带隙的半导体材料,具有优良的物理和化学性质,是目前光电子研究领域的热点。电化学自组装方法具有沉积速率高、操作温度低、可以在复杂衬底表面生长,成本低和环境友好等优点,而在材料合成领域受到广泛重视。本论文针对目前氧化锌材料研究领域的热点和难点,利用电化学自组装的方法在氧化锌材料制备和光电性能的应用方面开展了一系列的工作:详细研究了利用电化学自组装方法制备氧化锌薄膜和纳米粒子,探索了溶液化学法制备氧化锌纳米粒子的生长机理,讨论了制备条件对氧化锌纳米粒子的结构和光学性质的影响。将聚环氧乙烷(PEO)引入到电化学沉积电解液中,利用电化学方法控制ZnO的成核,利用PEO控制ZnO晶体的生长,获得分散的、具有高度c-轴取向的ZnO六棱柱,提出了PEO辅助定向生长ZnO纳米棒的机理,认为PEO与ZnO不同晶面的吸附强度不同,导致了ZnO侧面和端面的生长活性不同,从而促进了ZnO晶体的各向异性生长。定向生长的ZnO纳米棒阵列薄膜可用于聚合物太阳能电池结构,用以提高体系的电荷传输效率从而提高光伏电池效能。为此,我们制备了结构为ITO/ZnO/PAT6:PCBM/Au的本体异质结型聚合物光伏电池,当在器件结构中插入定向生长的ZnO纳米柱多孔薄膜层,电池的光伏性能有很大的改善,经过ZnO纳米柱生长分布密度和整体装置退火条件的优化分析,我们得到了光电转换效率为1.71%的的光伏电池。为了更加清楚的了解ZnO层在光伏电池结构中的作用,我们以相互浸润互穿网络型层层结构光伏装置为研究对象,分析对比了含不同结构ZnO层的器件性能,结果表明,定向生长的ZnO纳米柱多孔结构相比于平整结构的ZnO层更加有利于提高光电池的光伏性能;制备了含双层结构氧化锌的结构为ITO/double ZnO/C60/PAT6/Ag的光电池,在AM1.5(光强为100 mWcm-2)光照射下得到的光电转换效率为1.31%,短路电流为7.74 mAcm-2,开路电压为0.40 V和填充因子为41%。结合光电导原理,初步建立了关于不同结构ZnO薄膜对光电池效率的贡献的理论模型,分析了不同结构的氧化锌对光伏装置效能贡献的程度。并且以我们的理论分析为依据,提出了对该课题进一步研究的方向。更多还原

【Abstract】 Zinc oxide is a kind of wide band-gap semiconductor which has attracted extensive interest in the field of electrical and optical devices because of its multi-functionality. Electrochemical assembly is a simple and convenient method, has been extensively used in the synthesis of many different types of materials. It has several advantages such as low processing temperature, higher deposition rates, controllable film thickness and morphology.This dissertation was focused on the growth of ZnO thin films and nanoparticles using electrochemical assembly method, studying their physical properties, such as the structural, optical and electrical properties.Nonionic polymer poly (ethylene oxide) (PEO) was introduced into the zinc nitrate electrolyte to modulate the crystal growth and the morphology of ZnO by electrodeposition process. The PEO assistant oriented grown mechanism was put forward in this paper, different attached strength according to different crystal facets result in anisotropic grown activities between side facet and end facet.The ZnO arrays prepared by the electrochemical assembly method can be used as electron transportor in the solar cell, which can enhance the device’s performance. The bulk-junction type solar cell with the structure ITO/ZnO/PAT6:PCBM/Au was successfully fabricated. The cell’s photovoltaic performance was improved by inserting the oriented ZnO nanorod layer in the device. A device with a power coversion efficiency of 1.71% was obtained after optimizing the distribution of ZnO nanorods and the device’s annealing condition.In order to explore the effect of ZnO in the device further, different interpenetrating type devices with different structured ZnO were compared. The results implied the oriented porous structured ZnO has more contribution to the device’s performance compared to the flat structured ZnO. Double-layer ZnO structure was firistly used in the interpenetrating layer-layer type solar cell with the structure of ITO/double ZnO/C60/PAT6/Ag. Under AM1.5 irradiation, the device exhibits the excellent performace with a power coversion efficiency of 1.31%, a short circuit current of 7.74 mAcm-2, a open circuit voltage of 0.40 V and a fill factor of 41%. According to the photoconductive theory, a theoretic model about estimating the contribution value to the device’s photovoltaic performance was set up. Beae on this model, different devices with different structured ZnO were analysed, some new plans according to this topic was put forward.更多还原