Exceptional PbS/CsPbCl3 heterostructure based on the structural, electronic and optical properties of PbS/CsPbX3(X=Cl, Br, I)

The construction of heterojunction between NIR photoelectric materials and other types of materials has the potential to improve the performance of VIS-NIR photoelectric materials and broaden the absorption spectrum. In this study, the properties and theoretical calculations are carried out using the near-infrared photoelectric material PbS and the perovskite material CsPbX3 (X = Cl, Br, I) to build heterostructures. The appropriate lattice mismatch rates (4.5 %, 2 % and 4.6 %) between PbS and CsPbX3 (X = Cl, Br, I) ensure the feasibility of constructing PbS/CsPbX3 (X = Cl, Br, I) heterogeneous structures. The electronic properties calculations revealed physical mechanisms that improve luminous efficiency. Notably, the I-type band alignment (-5.02eV < PbS < -3.77eV, -5.85eV < CsPbX3 (X = Cl, Br, I) < -3.35eV) at the PbS/CsPbX3 (X = Cl, Br, I) interface facilitates efficient electron and hole transfer from the CsPbX3 (X = Cl, Br, I) quantum dots to the PbS material, which was further validated by the observed difference in charge density. Among them, the electron cloud of PbS/CsPbCl3 heterostructure is more obvious, and the charge transfer ability is better than that of the other two heterostructures. The heterostructures extend the light absorption range of CsPbX3 (X = Cl, Br, I) from visible to near-infrared under the influence of PbS. By comparing the light absorption functions, it is found that PbS/CsPbI3> PbS/CsPbCl3> PbS/CsPbBr3 in this range. Regarding comprehensive stability, charge density transfer, and optical properties, PbS/CsPbCl3 has the best performance. Under the premise of ensuring stability, different light absorption characteristics can be achieved by adjusting the composition of halogen atoms in PbS/CsPbCl3. This study provides a theoretical basis for enhancing the performance of the PbS/CsPbX3 (X = Cl, Br, I) heterostructures in VIS-NIR optoelectronic materials through investigations of their electronic and optical properties. It yields a promising approach for the design of high-performance VIS-NIR heterogeneous materials.