The First Principle Investigation Of Interface Interaction And Electronic Properties Of Two-dimensional Materials/CH₃NH₃PbI₃

Environmental pollution and energy crisis caused by social development and population increase have become two important problems for sustainable development of human society.Semiconductor photocatalysts are one of the most promising technologies to solve the two big difficult problems due to its low energy,consumption recyclability and no secondary pollution and have been widely used.The key photocatalytic technology is to develop photocatalytic materials and most semiconductors are broadband gap semiconductors.Therefore,develop new and efficient photocatalytic materials has become an import way to promote the development of photocatalytic technology.Organic-inorganic hybrid perovskite material CH₃NH₃PbI₃（MAPbI₃）has excellent photoelectric properties and is considered as an ideal material in the field of photocatalysis.However,the instability in wet environment and lower light quantum efficiency hinders its wide application as a photocatalyst.In this paper,the photocatalytic activity and stability of two-dimensional layered materials/MAPbI₃ materials and their potential applications in the field of photocatalysis were investigated by using the first-principles calculation based on density functional theory.The results are as follows:（1）The interfacial interaction,electronic and optical properties between SnS and MAPbI₃ composites with different layers were systematically studied.The result shows that compared with pure MAPbI₃,two-dimension SnS/MAPbI₃（100）nanocomposites have smaller optical band gaps（0.94,0.78 and 0.64 eV）.The light absorption intensity of the composites increased significantly in the wavelength range of 300-600nm（the light absorption intensity is about three times of that）,and the light absorption range has been extended to the whole visible region,even in the infrared region.The type-Ⅱ,staggered,band alignment existing the SnS and the MAPbI₃ can effectively reduce the photoinduced carriers recombination rate,so as to improve the photocatalytic activity.Two-dimensional SnS layered materials can prevent MAPbI₃ from direct contact with water molecules and effectively improve the stability of MAPbI₃ in air.These results can be used for reference in the research and development of new and efficient nanocomposites based on MAPbI₃ materials.（2）The effect of interaction on the electronic structure and optical properties of GR/MAPbI₃（100）composite system was systematically studied.The results showed that the band gap of the composite system was reduced by GR modification（0.78,0.54and 0.36 eV）.The light absorption range of the composite system is extended to the whole visible region and even the infrared region,and the absorption intensity is significantly enhanced（about three times of the pure MAPbI₃ at the same wavelength）in the wavelength range of 300-600nm.The type-Ⅱ,staggered,band alignment existing the SnS and the MAPbI₃ can effectively improve the lifetime of the photoinduced carriers,improve its photocatalytic activity,and the graphene improve the stability of MAPbI₃.These results provide design ideas for promoting the development of composite photocatalytic materials based on MAPbI₃ materials.