二维钙钛矿范德华异质结光电性质和电子输运性质研究

二维范德华异质结不仅具备优异的电学、光学和力学性质，还具有新的物理现象及功能，成为材料与器件领域的研究热点，展现出重要的应用前景。二维钙钛矿集合了二维材料和钙钛矿材料的优异特性，但是基于二维钙钛矿和新型二维材料构建的范德华异质结的界面光电性质及电子输运特性尚不清楚，极大限制了该钙钛矿范德华异质结在光电器件中的应用。本项目基于申请人前期对范德华异质结界面性质的系统研究，拟采用密度泛函理论及非平衡格林函数方法，构建二维钙钛矿/n型二硫化钼和二维钙钛矿/p型磷烯全二维范德华异质结构和器件模型，深入研究界面电子态和电子输运性质，阐明范德华相互作用对整个异质结能级、光学性质和电子输运性质的影响机制。进而通过施加外延电场、平面应力、界面耦合、掺杂及改变二维钙钛矿层数等方法，调控二维钙钛矿范德华异质结中各组份能带弯曲及界面势垒高度，为研制新型全二维钙钛矿范德华异质结光电器件提供重要理论指导。

The two-dimensional van der Waals heterostructure not only owns excellent electrical, optical and mechanical properties, but also exhibits new physical phenomena and functions, which becomes a research focus in the field of materials and devices, and shows significant potential for future optoelectronic applications. Two-dimensional perovskites own the excellent properties of two-dimensional materials and perovskite materials. But, the interface photoelectrical properties and Electron transport properties of the new two-dimensional materials and the two-dimensional perovskite materials van der Waals heterostructure are unclear and the application of two-dimensional perovskite materials in optoelectronic devices is greatly limited. In this project, the interfacial electronic structures and transport properties of (C4H9NH3)2PbBr4/n-MoS2 and (C4H9NH3)2PbBr4/p-BP two-dimensional van der Waals heterostructure and device will been investigated by using density functional theory coupled with nonequilibrium Green’s function method. The mechanism of the influence of van der Waals interaction on the energy levels, optical absorption and transport properties of the whole heterostructure will be elucidated. The energy band bending and interface barrier height of each component in the heterostructure will be tuned by applying the epitaxial electric field, stress, interface coupling, doping and changing the number of two-dimensional perovskite layers, which provide important theoretical guidance for the development of novel two-dimensional perovskite van der Waals heterostructure photoelectric device.