具有能隙梯度的全无机甲胺铅碘薄膜太阳能电池的能带设计、构筑与性能研究

钙钛矿型甲胺铅碘太阳能电池正经历令人惊讶的效率竞赛（近五年已由3.8%提升到15.7%），但许多基本科学问题有待解决。克服由材料制备本身引起的器件性能差异，并从光生载流子输运角度阐明不同类型电池的工作机理，是两个较为关键的科学问题。本项目拟综合采用液相、气相生长技术，通过优化生长条件，获得高质量带隙可调的甲胺铅碘薄膜；利用瞬态、稳态光致发光谱，测量其激子束缚能、载流子扩散长度等基本物理参数；利用能带理论，设计电池结构，调控界面结构，并寻找合适的无机空穴传输材料；最终组装出具有能隙梯度的全无机薄膜太阳能电池。进而，通过电流电压谱、量子效率谱和电化学阻抗谱等手段，系统研究甲胺铅碘吸光层能隙梯度及异质界面结构对电池效率的影响，从能带设计和界面调控角度，阐明不同电池光生载流子产生、分离、收集及复合规律。该项目不仅在学术上具有重要意义，还可为进一步优化甲胺铅碘薄膜电池结构与性能提供理论指导和材料基础

The efficiency of perovskite solar cell assembled with CH3NH3PbI3 is experiencing an amazing race, which was increased from 3.8% to 15.7% during the past five years. But, several fundamental issues need to be addressed. The two important questions are how to overcome the devices performance difference caused by the material preparation itself and how to clarify the working mechanism of different cell devices from point of view of photogenerated carriers transport properties. In this project, both solution and vapor deposition methods will be adopted and optimized to grow high quality CH3NH3PbI3 and its alloy with tunable bandgap. The exciton binding energy and carrier diffusion length will be measured by steady and transient photoluminescence spectroscopy. The device structure and its heterointerface will be designed and optimized with band gap theory and Anderson principle. Inorganic semiconductor will be selected for transporting holes defusing from optical active layer. Finally, P-i-N and DH perovskite thin film solar cells with bandgap grading will be fabricated and characterized with I-V, IPCE and EIS. The influences of CH3NH3PbI3 bandgap grading and interface heterostructure on the solar cell photovoltaic efficiency will be investigated. The photogenerated carriers transport mechanism like formation, separation, collection and recombination will be clarified by bandgap design and heterointerface control. This project is of great significance not only academically, but also provides theoretical guidance and materials basis for further optimization of device structure and properties of perovskite thin-film solar cells.