Optoelectronic properties and interfacial interactions of two-dimensional Cs(2)PbX(4)–MSe(2) (M = Mo, W) heterostructures

Constructing 2D inorganic perovskites and TMDs heterostructures is an effective method to design stable and high-performance perovskites optoelectronic applications. Here, we investigate the optoelectronic properties and interfacial interactions of Cs(2)PbX(4)–MSe(2) (X = Cl, Br, I; M = Mo, W) heterostructures using first-principles calculations. Firstly, six Cs(2)PbX(4)–MSe(2) interfaces remain stable in energy. With the halogen varying from Cl to I, the interlayer distances of Cs(2)PbX(4)–MSe(2) heterostructures increase rapidly. The CBM and VBM of monolayer Cs(2)PbX(4) are all higher than that of monolayer MSe(2) and the charges transfer from Cs(2)PbX(4) interfaces to MSe(2) interfaces when they contact. Both Cs(2)PbX(4)–MSe(2) heterostructures are type-II heterostructures, which can drive the photogenerated electrons and holes to move in opposite directions. What's more, Cs(2)PbCl(4)–MoSe(2) heterostructures exhibit the highest charge transport efficiency among Cs(2)PbX(4)–MoSe(2) heterostructures because Cs(2)PbCl(4)–MoSe(2) heterostructures have the lowest exciton binding energies among Cs(2)PbX(4)–MSe(2) heterostructures. In addition, the optical absorptions of all heterostructures are significantly higher than the corresponding Cs(2)PbX(4) monolayers and MSe(2) monolayers. The construction of Cs(2)PbX(4)–MoSe(2) heterostructures is beneficial for improving the photoelectric performance of two-dimensional perovskite devices. Lastly, we found that the Cs(2)PbI(4)–WSe(2) heterostructure has the largest PCE (18%) among Cs(2)PbX(4)–MSe(2) heterostructures. The Cs(2)PbCl(4)–MoSe(2) heterostructure exhibits great potential application in photodetector devices and the Cs(2)PbI(4)–WSe(2) heterostructure has great potential application in solar cells.