The covalent functionalization of exfoliated semiconducting MoS 2 by 1,2-dithiolanes bearing an ethylene glycol alkyl chain terminated to a butoxycarbonyl-protected amine and a photoactive pyrene moiety is accomplished. The MoS 2 -based nanohybrids were fully characterized by complementary spectroscopic, thermal, and microscopy techniques. Markedly, density functional theoretical studies combined with X-ray photoelectron spectroscopy analysis demonstrate preferential edge functionalization, primarily via sulfur addition along partially sulfur saturated zig-zag MoS 2 molybdenum-edges, preserving intact the 2D basal structure of functionalized MoS 2 -based nanohybrids as confirmed by high-resolution transmission electron microscopy and electron energy loss spectroscopy. Furthermore, in the MoS 2 -pyrene hybrid, appreciable electronic interactions at the excited state between the photoactive pyrene and the semiconducting MoS 2 were revealed as inferred by steady-state and time-resolved photoluminescence spectroscopy, implying its high potentiality to function in energy conversion schemes.

The combination of graphene with molecules offers promising opportunities to achieve new functionalities. In these hybrid structures, interfacial charge transfer plays a key role in the electronic properties and thus has to be understood and mastered. Using scanning tunneling microscopy and ab initio density functional theory calculations, we show that combining nitrogen doping of graphene with an electric field allows for a selective control of the charge state in a molecular layer on graphene. On pristine graphene, the local gating applied by the tip induces a shift of the molecular levels of adsorbed molecules and can be used to control their charge state. Ab initio calculations show that under the application of an electric field, the hybrid molecule/graphene system behaves like an electrostatic dipole with opposite charges in the molecule and graphene sub-units that are found to be proportional to the electric field amplitude, which thereby controls the charge transfer. When local gating is combined with nitrogen doping of graphene, the charging voltage of molecules on nitrogen is greatly lowered. Consequently, applying the proper electric field allows one to obtain a molecular layer with a mixed charge state, where a selective reduction is performed on single molecules at nitrogen sites.