【作者】 庄东填；

【导师】 林红；

【作者基本信息】 清华大学 ， 材料科学与工程， 2010， 硕士

【摘要】 染料敏化太阳能电池（DSC）是一种新型太阳能电池,其制作工艺简单、成本低,是硅电池的有力竞争者。然而,目前DSC存在着转换效率不高、长期稳定性差等缺点,限制了它的大规模应用。TiO₂是目前主要使用的光阳极材料,但是其表面态过多,电子迁移率较低,导致电子复合比较严重,电子传输速率较慢,成为制约电池效率提高的一个因素。ZnO具有与TiO₂类似的能带结构和较高的电子迁移率,是一种有希望的光阳极材料。本论文尝试使用电沉积法制备了一种新型的垂直基板生长的纳米带状ZnO光阳极并将其用于DSC。纳米带结构的光阳极可以减少界面电阻,进一步提高电子传输速率。发现电沉积的制备条件对ZnO光阳极的形貌有着显著的影响,因而对DSC的光电性能也起着直接的影响。研究发现,随着电解液浓度的降低,电沉积电压、电沉积温度的升高,所得电池的性能有所提高。同时,对影响ZnO电池性能的因素如膜厚、电极形貌等进行了详细的讨论。另一方面,ZnO会与常用的N719染料生成Zn²⁺/dye络合物,对电池的性能有较大的影响。为了抑制Zn²⁺/dye的生成,尝试对光阳极进行包覆以及采用量子点代替染料。发现由于包覆层的制备过程中有酸的存在,因而无法使用跟包覆TiO₂光阳极同样的方法来对ZnO光阳极进行包覆。因此本论文主要研究使用CdS量子点代替染料。讨论了敏化次数对电池性能的影响,在电沉积制备的ZnO纳米带光阳极上得到了与使用染料时相近的效率,说明量子点敏化对该ZnO光阳极是一种行之有效的敏化方式。更多还原

【Abstract】 Dye-sensitized solar cell （DSC）, a new type solar cell, will become a powerful competitor with silicon-based solar cells, owing to the simplicity of their fabrication procedures and low cost. However, its low light-to-energy conversion efficiency and poor long-term reliability limit its large-scale ap-plication. TiO2 is the primary photoanode material; however, the surface state may confine electron mobility and cause recombination, which limits the in-crease in cell conversion efficiency.ZnO has been regarded as a promising candidate photoanode material with its similar band gaps as TiO2 and higher electronic mobility. Here a new nanobelt type ZnO photoanode was fabricated by electrodeposition and ap-plied to DSC. Using nanobelt structure ZnO can efficiently reduce resistance at the interfaces of crystal grains. The electrodeposition conditions affected the ZnO morphology and thus the performance of DSC remarkly. The effi-ciency of DSC increased with decreasing surfactant concentration or increas-ing electrodeposition potential or temperature. The influencing factors of ZnO-based solar cells such as film thickness and ZnO film morphology were also investigated.On the other hand, as the generation of Zn²⁺/dye aggregates will limit the increase of ZnO-based solar cells efficiency, coating and quantum-dots were used to suppress the formation of Zn²⁺/dye aggregates. As the coating method for TiO2 photoanode will cause the formation of acid, it was not suitable for coating ZnO photoanode. Here quantum-dots were used to replace dye and efficiency comparing favorably with sensitized with dye was obtained, which indicated that quantum-dots were efficient sensitizer for the ZnO photoanode.更多还原