Electronic structure and optical performance of PbI2/SnSe2 heterostructure

•The PbI2/SnSe2 heterostructure possesses an indirect band gap semiconductor and exhibits a type-I band alignment.•The optical absorption of the PbI2/SnSe2 heterostructure in both the visible light and ultra-violet regions is enhanced.•Type-I to type-II band alignment and the semiconductor to metal transitions are also observed in the PbI2/SnSe2 heterostructure when the electric field is applied. Constructing van der Waals heterostructures can be considered as an effective strategy for generating new physical phenomena that merit for high-efficiency nanodevices. Here, we construct the PbI2/SnSe2 heterostructure using first-principles calculations and explore its electronic structure and optical performance as well as the effects of electric fields. The PbI2/SnSe2 heterostructure owns an indirect band gap and exhibits type-I band alignment, making it promising candidate for light emission applications. Furthermore, the optical absorption of the PbI2/SnSe2 heterostructure in both the visible light and ultra-violet regions is enhanced as compared with that of the PbI2 and SnSe2 monolayers. Furthermore, in the PbI2/SnSe2 heterostructure, the electric fields can convert the type-I to type-II band alignment and tune the transition from semiconductor to metal. Our results provide useful guidance for practical application in high-efficiency nanodevices.