First-Principles and Experimental Insights into Interfacial Structures and Properties between MAPbI3 and ZnIn2X4 (X = S, Se)

The interface between the MAPbI3 perovskite and layered ZnIn2S4 was investigated by first-principles calculations combined with the experimental study. To begin with, four different types of interfacial configurations were established and carefully examined. The interaction occurring between MAPbI3 and ZnIn2X4 is mainly determined by weak van der Waals forces. The interfacial charge reorganization implies electron transfer from the MAPbI3 layer to the ZnIn2X4 layer across the interface. The PbI/ZnIn2X4 interface exhibits stronger interfacial interactions compared to those of the MAI/ZnIn2X4 counterpart. The interfacial adhesion work was found to depend more on the surface termination of MAPbI3 than on that of ZnIn2X4. Conversely, it was discovered that the interface potential drop, work function, and dielectric function within the MAPbI3/ZnIn2X4 interfaces are predominantly regulated by ZnIn2X4 termination rather than MAPbI3 termination. Chalcogen vacancies cause enhanced interfacial interactions owing to electron rearrangements at the interfaces. In the end, the MAPbI3/ZnIn2S4 heterostructure was successfully fabricated and then characterized, which effectively verified first-principles calculations. This study offers fundamental insights into the development of MAPbI3/ZnIn2X4 heterostructures, advancing perovskite-based optoelectronic devices.