First-principles insights into the role of edges in the binding mechanisms of Au4 clusters on MoSe2 nanoflakes.

An atomistic understanding of the interaction between Au clusters and dichalcogenides nanoflakes of different polytypes is fundamental to improve our knowledge to the tuning of the physical-chemical properties of hybrid dimensional composite materials. Here, we report a density functional theory investigation into the changes of structural, energetic, and electronic properties induced by the adsorption of Au 4 clusters (planar and tetrahedron) onto Mo 16 Se 32 and Mo 3 6Se 7 2 nanoflakes of both 1T' and 2H polytypes. We found that the Au–Se interaction plays a critical role in the nature of the Au 4 /MoSe 2 interactions, in which there is a strong energetic preference for the S atoms located at the edges for all nanoflake sizes and polytypes. In summary, the Au⋯MoSe 2 binding mechanisms is composed of either (i) splitting of Se sp 2-orbitals interacting with Au sd 3-orbitals, or (ii) re-hybridized Au sd 3 splitting of Mo d z 2 -orbitals, with low charge transfer in both due to Au 4 cluster electron filling. Furthermore, the cluster/nanoflake adsorption energetics and structural distortions due to the Au⋯MoSe 2 interactions are mainly determined by the MoSe 2 edge configurations. Image 1 • We found that laterally stacked Au4/1T0-MoSe2 are the most stable configurations for both nanoflakes sizes, but with laterally stacked Au4/2H–MoSe2 exhibiting the more intense adsorption energies due to interaction of the Au4 clusters with 2H–MoSe2 armchair and zigzag configurations. • The S atoms at the edges plays a critical role in the Au-MoSe2 interactions. • The adsorption properties of Au4 on the MoSe2 nanoflakes are mainly determined by the edge configurations. [ABSTRACT FROM AUTHOR]