【作者】 李胜军；

【导师】 杨世伟；

【作者基本信息】 哈尔滨工程大学 ， 材料学， 2008， 博士

【摘要】 在过去近二十年里，染料敏化纳晶太阳能电池一直是世界各国能源研究的热点课题。染料敏化纳晶太阳能电池已经成为最有可能取代传统的p-n结太阳能电池的光电转换器件。纳晶TiO₂薄膜电极是染料敏化太阳能电池的重要组成部分。本论文制备了ZnO修饰的纳晶TiO₂薄膜电极和具有规则球形大孔的纳晶TiO₂薄膜电极，并对所制备的新型TiO₂薄膜电极及其组成电池的性能进行了详细的研究。采用溶胶．凝胶水热法制备了锐钛矿结构的纳晶TiO₂薄膜电极，采用EC/PC电解质体系组装染料敏化太阳能电池。并通过对纳晶TiO₂薄膜太阳能电池中电解质体系的吸光度、交流阻抗、暗电流等参数的测量，研究了I₂和KI含量对电池光电性能的影响原因。在溶胶．凝胶水热法制备TiO₂胶体的过程中，加入醋酸锌，制备了ZnO修饰的TiO₂薄膜电极。在（EC:PC=1:1，V/V）+0.5mol/L KI+0.05mol/L12+0.05mol/L LiI电解质体系中，利用ZnO修饰的TiO₂薄膜电极组装的电池光电转换效率可达到5.89%，相对于纯TiO₂薄膜电极组装的电池提高了20%。通过暗电流、瞬态光电流、交流阻抗以及平带电位等测试探讨了ZnO修饰提高电池光电性能的机理。添加适量聚丙烯腈到EC/PC电解质体系（（EC:PC=1:1，V/V）+0.5mol/LKI+0.05mol/L U2）形成准固态电解质，组装了准固态染料敏化太阳能电池，研究了电池中的离子扩散性能和光电性能。发现随着电解质体系粘度的增加，I₃^-离子扩散系数急剧下降，进而在准固念染料敏化太阳能电池的光电转换过程中形成新的速控步骤I₃^-离子的扩散过程。通过TiO₂薄膜电极厚度、电解质中I2添加量等因素对I₃^-离子扩散及电池光电性能的影响研究，进一步证实在准固念染料敏化太阳能电池中I₃^-离子扩散过程很可能是电池光电转换过程的速控步骤。采用种子乳液聚合的方法制备了形状规则、颗粒分布均匀的聚苯乙烯微球，将制备的聚苯乙烯微球作为造孔剂应用到纳晶TiO₂薄膜电极的制备过程中，制备了含有规则球形孔隙的纳晶TiO₂薄膜电极。规则球形孔隙的存在提高了纳晶TiO₂薄膜电极的光散射性能，进而提高薄膜电极的吸光效率。比较I₃^-离子在不同孔隙结构纳晶TiO₂薄膜电极中的扩散性能，发现纳晶TiO₂薄膜电极的孔隙结构对I₃^-离子的扩散性能具有很大的影响，而且随着电解质粘度的增大，影响越来越明显。I₃^-离子在具有规则球形孔隙结构的纳晶TiO₂薄膜电极中具有较好的扩散性能，而且在含有200nm规则球形大孔的纳晶TiO₂薄膜电极中扩散性能最佳。将含有200nm规则球形大孔的纳晶TiO₂薄膜电极应用在准固态染料敏化太阳能电池中，可以削弱I₃^-离子扩散对电池光电性能的影响，提高电池在高光强下的短路光电流。更多还原

【Abstract】 Over the past decades dye-sensitised nanocrystalline solar cells have been the subject of intense research and development efforts. These systems provide a technically and economically credible alternative to classical p-n junction solar cells.The nanocrystalline TiO₂ electrode plays an important role in dye-sensitized solar cells. In this thesis, the TiO₂ electrode modified by ZnO and the TiO₂ electrode containing large regular spherical nanovoids were made, and the properties of the two new TiC₂ electrodes as well as the performance of assembled solar cell were also studied.The anatase nanocrystalline TiC₂ was prepared by sol-gel method. Dye-sensitized solar cell was assembled using the EC/PC solution as electrolyte. The influence mechanism of the content of I₂ and KI on the photoelectric properties of the solar cell was explored through the measurement of some parameters of the electrolytes such as absorbance, impedance and dark current.ZnO modified TiO₂ electrode was obtained by adding Zn（CH₃COO）₂·2H₂O during the preparing process of TiO₂ colloid. The conversion efficiency of 5.89% was achieved in the electrolyte- （EC:PC=1:1, V/V） +0.5mol L^-1 KI+0.05mol L^-1 I₂+0.05mol L^-1 LiI, which was much higher than the conversion efficiency of 4.98% obtained by the pure anocrystalline TiO₂ electrode. Some experiments, such as darck current, transient photocurrent, impedance and flat band potential, were carried out to explore the causes for the enhancement of conversion efficiency.Polyacrylonitrile was added into the electrolyte-（EC:PC=1:1, V/V） +0.5mol L^-1 KI+0.05mol L^-1 I₂ to prepare quasi-solid state electrolyte. Quasi-solid state dye-sensitized solar cell was assembled and the photoelectric properties and ion diffusion performance were investigated. With the increasing of the viscosity of electrolyte, the diffusion coefficient of I₃ ion decreased rapidly to be a new controlling step in the quasi-solid state dye-sensitized solar cell. This consequence was confirmed by the studying of effect of TiO₂ film thickness and the content of I₂ on the diffusion process of I₃ ion and the photovoltaic performance.Monodispersed polystyrene microspheres with uniform diameter and regular shape were obtained through seed emulsion polymerization. The polystyrene microspheres were used as pore former to prepare nanocrystalline TiO₂ film with regular spherical nanovoids. The presence of regular spherical nanovoids improved the light scattering property of the nanocrystalline TiO₂ electrode. More important thing was that the pore structure of nanocrystalline TiO₂ electrode had great effect on the I₃ ion diffusion properties in the solar cells and this effect was greater in the electrolyte with higher viscosity. The I₃ ion could diffuse more rapidly in the TiO₂ film with regular spherical nanovoids than the TiO₂ film with randomly packed pore structure and in the nanocrystalline TiO₂ film electrode with 200nm regular spherical nanovoids, I₃ ion had the highest diffusion velocity. The nanocrystalline TiO₂ electrode with 200nm regular spherical nanovoids was used in quasi-solid state dye-sensitized solar cells. It was found that the effect of I₃ ion diffusion performance on the photovoltaic properties was reduced and the short circuit current under high light intensity was improved.更多还原