Molecular attachment onto single-layer MoS₂ is facilitated by Nb doping

Nb doping in single-layer MoS₂ creates an electron deficiency in the 2D layer, which may facilitate functionalization of the layer. Using first-principle calculations, we investigated the relative molecular attachment energies of –CH₃, –CH₂ and –CH onto single-layer MoS₂ with or without Nb doping. If the number of Nb dopants in the layer matches the bond order of the ligand, the electron deficiency is compensated; this stabilizes the system by ~1 eV. Excess Nb does not contribute significantly to further stabilization but does facilitate attachment of additional ligands. The effect extends to one or two lattice constant separation between the Nb dopant(s) and the attachment site with only a modest reduction in the degree of stabilization. These results suggest that electron deficiency could be used as a general strategy for molecular attachment to 2D materials.