A first-principles study of interfacial vacancies in the β-CsPbI/1T-MoS heterostructure towards photocatalytic applications.

Halide perovskite (HP) composites with transition metal dichalcogenides (TMDs) have attracted attention as promising photocatalysts for hydrogen production through solar-driven water splitting but their working mechanism is yet unclear. Here, we propose novel heterostructures composed of all-inorganic HP β-CsPbI and metallic TMD 1T-MoS and investigate the influence of interfacial vacancies on their interfacial properties using first-principles calculations. Using CsPbI(001)/MoS(001) interface slab models with a minimal lattice mismatch, we calculate the interface formation and interlayer binding energies, finding that the PbI-terminated interfaces have better stability and stronger binding strength than the CsI-terminated ones and iodine vacancy enhances the binding properties.