Electronic Properties of Triangle Molybdenum Disulfide (MoS 2 ) 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.