混合钙钛矿太阳能电池界面结构的理论设计：稳定性与效率

Solar energy as clean and renewable energies, are expected to solve the energy crisis. The development of a stable and efficient new generation of photoelectric materials has become the focus of scientific research. Layerd organometal halide perovskite solar cells are expected to be industrialized as the third generation of solar cells. The synthesis of perovskite with mixed ions and surface modification could improve the performance of perovskite. However, duo to the structure of mixed perovskite is very complex, the relationship between the interface structures and the stability and the mechanism of the carrier transfer is unclear. It is difficult to further improve the stability while increase efficiency. In this project, we plan to combine multiple-scales calculations include high-throughput density functional theory (DFT) calculations, first-principle molecular-dynamics and time-dependent DFT calculations to investagate the interfaces between the perovskite and the electron/hole transport materials. We attempt to systematically study the relationship between the structure and the thermodynamic stability of mixed ion perovskite, simulate the dynamic process of water molecules on the modified surface and explore the mechanism of excited state carrier transfer between interfaces. Following these, the high-performance perovskite based photoelectric materials will be designed and optimization by adjusting the chemical composition. Our project can provide suggestions and scientific basis for the stable and efficient solar cells.

太阳能作为清洁可再生能源，有望解决人类面临的能源危机。开发稳定高效的新一代光电材料成为科学研究的重点。层叠钙钛矿太阳能电池有望作为第三代太阳能电池工业化生产。对钙钛矿进行混合离子与表面修饰，在一定程度上能够改善其性能。但是混合离子钙钛矿组分复杂，界面结构尚不清楚，导致其与稳定性关系不明确，载流子传输机制不明晰，存在稳定性与效率难以同时兼顾的问题。本项目拟通过高通量密度泛函理论，第一性原理分子动力学和非绝热分子动力学，多尺度方法结合，针对钙钛矿与电子空穴传输材料界面这一决定性位置，首先系统的研究混合离子钙钛矿界面化学组成结构与热力学稳定性的关系规律，然后模拟水分子在修饰表面的动力学演化过程，提高其表面动力学稳定性。在此基础上，深入探究界面间激发态载流子传输时间机制。在理解上述机制情况下，合理优化设计钙钛矿界面化学组成，为稳定高效的新型太阳能电池提供相关的科学依据。

通过第一性原理计算，分子动力学，非绝热电声耦合计算研究了卤化钙钛矿用于太阳能电池的光电性质进行了研究和探索。取得了一些创新成果和结论：1 发现了钙钛矿中有机离子偶极取向排列对钙钛矿电子性质的影响，其主要表现为带边电荷的局域现象，是由于偶极排列引起的区域静电势不均，导致带边能级变化引起的。2 总结归纳了钙钛矿相关计算的理论方法。3 对混合离子钙钛矿稳定结构进行了探索，运用了第一性原理分子动力学探究了混合离子钙钛矿在室温条件下结构演化过程以及电子性质的影响。此外，我们对其他新型材料如磷烯，C3N4进行了研究，发现了其新颖的机械性能，或者在催化方面的应用。