水电解质pH值的调控及其对p型染料敏化太阳能电池光电性能的影响和机理研究

The study of p-type dye-sensitized solar cells (p-DSCs) is of great importance for pn-DSCs which has theoretical energy conversion efficiency of 43%. However, up till now, these p-DSCs have been fabricated with liquid electrolytes using organic solvents. Such solvents have the potential disadvantages of high vapor pressure and, more importantly, are not environmentally friendly. Water as an earth-abundant resource and clean solvent is ideal for the preparation of the electrolytes. Based on the above reasons, we intend to introduce [Co(en)3]2+/3+ as redox couple into the preparation of aqueous electrolytes, in conjugation with two types of p-type working electrodes (NiO and CuCrO2) for the fabrication of p-DSCs. By adjusting pH of the electrolytes, we are able to optimize the flatband potential of the semiconductor working electrodes as well as the redox potential of the electrolytes, and eventually, the energy conversion efficiency and the stability of the p-DSCs. Moreover, we will study the mechanism of the hole recombination (either with reduced species in the electrolyte or with the reduced dye) at the interface between the working electrode and the aqueous electrolyte. This study will provide theoretical explanations for p-DSCs with good performance and stability.

p型染料敏化太阳能电池（p-DSCs）的研究对于大幅度提高叠层电池的光电转化效率（理论值为43%）具有非常重要的意义。可是目前看来，不仅关于p-DSCs的研究比较少，而且所研究的p-DSCs中仍旧使用了有毒、易燃并且易挥发的有机溶剂作为电解质溶剂。水具有无毒、低挥发、不燃烧、廉价易得等的优点，以它来代替有机溶剂可以缓解目前国内尤为迫切需要解决的环境污染问题。本项目针对环保和提高光电转换效率两方面的问题，将[Co(en)3]2+/3+氧化还原电对引入到水电解质的制备中，并采用两类不同的p型工作电极材料（NiO型和CuCrO2型）组装成DSCs。通过改变水电解质的pH值来调节半导体的平带电位和电解质的氧化还原电位，以此来优化太阳能电池的光电转换效率和稳定性。研究不同pH值对器件中工作电极/电解质界面处光生空穴的复合机制和影响规律，为高性能稳定性好的p型水DSCs提供理论指导。