二维材料/铁电薄膜异质结的光电化学效应及其调控机理研究

The semiconductor-based photoelectrochemical technology shows great prospect in solving energy and environmental issues, but the low solar energy utilization and quantum efficiency of traditional photoelectrode materials are still the main obstacle for their applications. The development of highly efficient photoelectrodes with visible light response is vital to the industrial application of photoelectrochemical technology. In the project, ferroelectric materials BiFeO3 (BFO) with visible light absorption performance will be combined with two dimensional (such as MoS2、g-C3N4 ) to harness their synergistic effect，thereby extending the excitation wavelength, suppressing the recombination of photogenerated carriers, and improving the stability of the photoelectrodes. First, two dimensional materials/ferroelectric heterostructure photoelectrodes with various architectures will be designed and constructed. The key factor that affects the size, shape, distribution of the two dimensional materials and the performance of the ferroelectricity in the heterostructure will be systematically investigated, so as to realize the controllable synthesis of the heterostructure. Then, the photoelectrochemical performance of the two dimensional materials/ferroelectric heterostructure photoelectrodes will be systematically researched. With the help of the theoretical works, the microstructure and the interface of the heterostructure, the ferroelectricity, and the microstructure of the two dimensional materials on the photoelectrochemical performance will be also discussed, which can help us to reveal the behind mechanism of the synergistic effect between two dimensional and ferroelectric materials. It is expected that the study in this project can construct experiment and theoretical basis for the development and application of high-performance two dimensional materials/ferroelectric photoelectrodes.

半导体光电化学技术在解决能源和环境问题方面有着广阔的应用前景，但传统光电极的太阳能利用率和量子效率低仍是限制其应用的主要因素，开发可见光响应的高性能光电极是光电化学技术的关键。本项目拟将具有可见光响应的铁电薄膜（BiFeO3）与二维材料（主要以MoS2、g-C3N4为主）复合构筑成异质结光电极，通过发挥二者的协同优势，达到拓宽光响应范围、促进光生载流子分离、提高光电极稳定性的目的。首先将从二维材料单元尺寸、形状控制以及铁电薄膜性能等方面入手，系统地研究影响二维材料与铁电薄膜复合方式的关键因素，实现异质结体系的可控合成。其次，深入研究二维材料/铁电薄膜异质结光电化学性能。最后与理论工作相结合，探讨复合体系和异质界面的结构类型、铁电薄膜状态、二维材料组成和结构等对光电化学性能的影响。揭示二维材料与铁电薄膜之间的协同作用机制，为二维材料/铁电薄膜异质结光电极的实际应用提供实验和理论基础。

半导体光电化学技术在解决能源和环境问题方面有着广阔的应用前景，但传统光电极的太阳能利用率和量子效率低仍是限制其应用的主要因素，开发可见光响应的高性能光电极是光电化学技术的关键。通过本项目的实施，我们实现了具有可见光响应的铁电薄膜（BiFeO3）与二维材料（主要以MoS2、g-C3N4为主）复合异质结光电极的有效构筑，通过发挥二者的协同优势，达到了拓宽光响应范围、促进光生载流子分离、提高光电极稳定性的目的。本项目分三个层次进行了研究，1、从二维材料单元尺寸、形状控制方面入手，系统地研究了影响二维材料的能带结构和导电类型，完成了二维纳米复合材料的适配选型。2、从材料的极化大小、退极化场以及铁电屏蔽场等耦合作用入手，系统研究了铁电极化对异质结光电化学特性的调控作用，提出了局域铁电极化对光生空穴传输的保护机制和铁电光伏各向异性的物理本质。3、系统研究了二维材料/铁电（薄膜、粉体）材料复合光电极的光电化学性能，理清了界面异质结对光电化学性能提升的物理根源，并深入挖掘了多结复合的协同效果；并与理论工作相结合，探讨复合体系和异质界面的结构类型、铁电薄膜状态、二维材料组成和结构等对光电化学性能的影响。