钙钛矿太阳能电池理论研究：界面结构、性质与调控

钙钛矿太阳能电池界面理论研究滞后于实验研发。拟为该电池建立相对完备的界面微观模型并探讨界面结构和性质对电池性能的影响机理：采用第一性原理计算辅以器件模拟方法在电子、原子和器件三种结构层次上系统研究电子传输层|CH3NH3PbI3光吸收层|空穴传输层|金属电极各界面的局域晶格结构（晶向匹配、晶格失配、紧邻层成分、键长、键角及晶格缺陷等）和光电性质（复介电常数、吸收系数、能带匹配、界面态及其密度、功函数和势垒等）。重点探究界面能带匹配、势垒和态密度对电池性能（开路电压、短路电流、填充因子和光电转换效率）的影响规律，在已有实验界面调控方法基础上寻求更多可能的界面调控措施。目的是用多层次结构的定量数据建立该电池的界面模型，深刻理解界面局域结构-性质-电池性能的相关关系，为设计电池（界面）化学成分、修饰界面结构、调控界面性质、发挥所谓“界面工程”的作用提供参考，为提高电池性能提供理论引导和帮助。

For the interfaces in peroviskite solar cell, theoretical investigation is behind the experimental research and development on them. We will establish relatively sophisticated interfacial micro-models for peroviskite solar cell and reveal the micro-mechanism of photoelectric properties affected by the interfaces (structures and properties). We will use the first principles calculation aided by device simulation to systematically study the local lattice structures and photoelectronic properties of the interfaces located in electron transfer material | CH3NH3PbI3 light-absorbing layer | hole transfer material | metal electrode at electronic, atomistic and device levels. For the local lattice structures, lattice direction match, lattice mismatch, chemical composition in the adjacent layers, bond lengths, bond angles and lattice defects will be considered. For the photoelectric properties, complex dielectric function, absorption coefficient, energy band alignment, interface states and their densities, work function and potential barriers will be calculated. The effects of energy band alignment, height of potential barrier and quantity of density of states are focused for the cell’s performance (open-circuit voltage, short-circuit current, fill factor and photoelectric conversion efficiency). Then more potential manipulation measures for the interfaces will be proposed basing on the previous experimental manipulation methods. The aim of this research is to construct the interface models, to deeply understand the relationship among the local lattice structures of the interfaces, interface properties and perovskite solar cell’s performances. As theoretical guides, quantitative results at multi-scale will be helpful to design chemical components of the cell’s materials and those at the interfaces, to modify the interface structures, to manipulate the interface properties, to take the advantage of so called interface engineering and then to improve the cell’s performances.