Electronic Properties of Triangle Molybdenum Disulfide (MoS) Clusters with Different Sizes and Edges.

The electronic structures and transition properties of three types of triangle MoS clusters, (Mo edge passivated with two S atoms), (Mo edge passivated with one S atom), and (S edge) have been explored using quantum chemistry methods. The highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gap of B and C is larger than that of A, due to the absence of the dangling of edge S atoms. The frontier orbitals (FMOs) of A can be divided into two categories, edge states from S at the edge and hybrid states of Mo and S covering the whole cluster. Due to edge/corner states appearing in the FMOs of triangle MoS clusters, their absorption spectra show unique characteristics along with the edge structure and size.