有机-无机杂化钙钛矿光伏材料的相变机制及带隙调控

Solar photovoltaic power generation is to solve the increasingly serious energy and environment problem in current state. An effective methods is applied the organic-inorganic perovskite solar cells, which has achieved the photoelectric conversion efficiency of surge in just a few years. Of course, it is the most poplar and the highlights in energy research at present. Recently, it is devepoped a lot depend on the experimental research, which effectively promote the materials and devices designs, deepened to the complex system of charge generation and transport process of research, enhance the different crossover development in the field of photoelectric. But, at the same time, theoretical research and its mechanism remains to be further lacked. This project intends to through the organic-inorganic hybrid perovskite materials (CH3NH3PbX3) in the first principles calculation on the three phase structure of organic-inorganic perovskite. Using the first principle calculation for energy of organic ion at different orientation, by comparing the phonon spectrum and thermodynamic interpretation or reveal different crystal structure of the phase stability and mechanism of phase transformation. For MA+ and FA+ ions to form laminated will improve the working mechanism of the photovoltaic performance of the materials. Moreover, to control its band gap and select the doped element, we can get a suitable band gap to get more light from sun. We plan to know the mechanism of the excellent photovoltaic properties of organic-inorganic hybrid perovskite, which would help us to discover or increasing the properties of new solar cel materials from electron-atom view. All of the research would help us to explore the new type of low cost, high efficiency photovoltaic material.

太阳能光伏发电是解决目前日益严重的能源与环境问题的一种有效手段，有机-无机杂化钙钛矿太阳能电池, 在短短几年内实现了光电转换效率的飙升,成为目前新型太阳能电池的研究热点之一。 实验研究有效促进了材料和器件设计, 加深了对复杂体系的电荷产生、输运过程的研究, 增强了不同光电领域的交叉发展, 但同时理论研究和机理有待进一步加强。本项目拟通过有机-无机杂化钙钛矿材料(CH3NH3PbX3)中主要存在的三种相结构展开理论计算研究，采用第一原理计算获得有机离子不同取向的能量，通过研究声子谱和热力学解释或揭示相稳定性及不同晶体结构的相变机制。针对MA+离子和FA+离子形成叠层会提高材料的光伏性能进行工作机理研究，阐明其带隙调控机制，以及通过高通量计算选择和预测不同阴阳离子对钙钛矿光学性质的影响规律，从电子-原子层次上探索与改进新型钙钛矿太阳能材料，相关研究能够加速实现低成本、高效率的新型光伏材料。

太阳能光伏发电是解决目前日益严重的能源与环境问题的一种有效手段，有机-无机杂化钙钛矿太阳能电池, 在短短几年内实现了光电转换效率的飙升,成为目前新型太阳能电池的研究热点之一。实验研究有效促进了材料和器件设计, 加深了对复杂体系的电荷产生、输运过程的研究, 增强了不同光电领域的交叉发展, 但同时理论研究和机理有待进一步加强。本项目通过第一性原理计算对有机-无机杂化钙钛矿材料光电转换进行深入研究的同时，提出了几种新型的有机-无机杂化钙钛矿材料，包括CH3NH3CdxPb1-xI3、CH3NH3MgxPb1-xI3、零维钙钛矿材料等，并详细研究了其光学、力学性质。不仅在理论方面，本项目在实验方面也取得了突破。开发了几种有机无机杂化钙钛矿单晶的制备技术，并成功生长出超过1厘米的大尺寸有机无机杂化钙钛矿单晶。利用钙钛矿单晶，本项目对其诸多性质进行探究，发现其具有超低热导与超高热膨胀，从热学性能方面对提高钙钛矿器件本征稳定性提出指导，同时提出了钙钛矿材料在热电材料方面的应用潜力。