Functionalization\nof Monolayer MoS<sub>2</sub> with\nLayered Multimolecular Architectures

Two dimensional van der Waals materials have attracted\nattention\ndue to their unique properties that arise in the monolayer versus\nbulk limits. Monolayer MoS<sub>2</sub> has been at the forefront of\n2D materials due to its broad applicability in catalysis, photovoltaics,\nand spintronics. To realize the capabilities of MoS<sub>2</sub> enabled\ntechnology, it is necessary to engineer interfaces where charge carriers\ncan be funneled toward or away from the surface. Molecular systems\nare a versatile strategy to enable this. Ion-linked molecular architectures\nhave been used previously to circumvent difficult and taxing synthetic\nmethods. Here, we demonstrate the growth of metal ion-linked bilayers\n(ILBs) on monolayer MoS<sub>2</sub> consisting of a first layer spacer\n(4-mercaptobenzoic acid, MBA) with a Zn(II) ion linked to a fluorophore\n(BODIPY). Using a combination of Atomic Force Microscopy and Raman\nspectroscopy, we resolved intrinsic S-vacancies in the MoS<sub>2</sub> lattice via S–H bond breaking of MBA. X-ray Photoelectron\nSpectroscopy confirmed that Zn(II) acetate can coordinate to carboxylate\ngroups on MBA. With photoluminescence microscopy, we determined that\nBODIPY emission is observable only in the presence of a metal ion,\nconfirming the growth of a multimolecular ion-linked supramolecular\nassembly on MoS<sub>2</sub>.