First-principles study on the structures and electronic properties of the PbnI and PbnI2 (n = 1–6) clusters

Abstract

To investigate the configurations and the electrical performance of the Pb–I films, the geometries and electronic properties of the Pb[Formula: see text]I and Pb[Formula: see text]I2 (n = 1–6) clusters are calculated by density functional theory at the GGA/PBE functional. The results reveal that I atoms prefer to occupy the symmetrical positions which are far from the centers of the Pb[Formula: see text] clusters. The Pb2I2 clusters are more structurally stable than the neighbors by the average binding energy. The PbI, Pb3I, PbI2, Pb4I2 and Pb6I2 clusters are more dynamically stable than their neighbors by the HOMO–LUMO gaps. The adsorption capacity of an I atom on the Pb2 cluster is the strongest compared to those of the other Pb[Formula: see text] (n = 1–6) clusters. NBO analysis reveals that the 5p orbital of I atoms in the Pb–I clusters acquires more electrons than the 5s orbital loses.