量子点敏化半导体多孔微球的构筑及其在太阳电池光阳极中的应用研究

To improve the visible-light utilization and photogenerated charges transfer performance, semiconductor porous microspheres with light scattering effect will be synthesized firstly. Then according to the principle of energy band matching, the electrodes based on semiconductor porous microspheres will be sensitized by the quantum dots. At last, the electrodes will be used as photoanodes to fabricate quantum-dots-sensitized solar cells. The properties of photogenerated charges in the photoanodes will be thoroughly and systematically studied by surface photovoltage measurements, and the law of generation, separation and recombination of photogenerated charges will be revealed. The relationship of the semiconductor thin film structure (interface structure, pore size, porosity, grain size, grain type), the behavior of photogenerated charges, photoelectric conversion efficiency of the solar cells will be explored to provide the basis for optimizing the structure and properties of the photoelectric conversion materials. The diffusion behavior of photogenerated electrons will be controlled by reducing the defect states and introducing electron transporting materials. At last, experimental and theoretical improvements of the photoanode model will be obtained to build quantum-dots-sensitized solar cells with high photoelectric conversion efficiency.

以提高可见光利用效率和光生电荷传输性能为目标，首先制备具有光散射效应的半导体多孔微球材料，再根据能级匹配原则设计量子点敏化的半导体多孔微球薄膜电极，最后以该电极为光阳极构筑高效量子点敏化太阳电池。利用表面光伏技术深入系统的研究所构筑的光阳极内部光生电荷性质，揭示该结构下光生电荷的产生、分离、复合过程的规律。探索半导体薄膜结构（界面结构、孔径、孔隙度、粒径、晶型）、光生电荷行为、太阳电池光电转换效率三者之间的关系，为优化光电转换材料的结构和性能提供依据。通过降低材料内部缺陷态以及引入电子传输材料来实现光生电子扩散的调控。最终从实验和理论上完善高效量子点敏化太阳电池光阳极模型，构筑具有高光电转换效率的量子点敏化太阳电池。

本研究围绕太阳电池光阳极材料的光散射、能带结构、界面电荷分离等问题，制备了尺寸在亚微米级别的高比表面积半导体多孔微球，依据能级匹配原则对半导体多孔微球进行了量子点敏化，最终作为太阳电池光阳极材料进行研究。通过系统的研究，积累了丰富数据，创立相应的理论模型，形成有创新特点的测试方法。取得了一些重要研究成果：1）TiO2介孔微球展现了良好的可见光光散射能力，比表面积达到197 m2/g。2）硫族半导体敏化的多孔微球具有很好的界面电荷分离能力，基于其制备的太阳电池短路电流达到8 mA/cm2。 3) p型半导体BiOI和石墨烯量子点（GOQDs）作为新型材料应用在量子点敏化太阳电池，获得了较好的光电转换效率。4）表面光伏调制频率技术被用于研究量子点敏化太阳电池光阳极材料，获得了光生电荷在电极内扩散传输及复合性质。