Use of the basal plane of 2D transition-metal dichalcogenides (TMDs) as supports for catalysts could widen their applications in fuel cells and chemical processing by taking advantage of their high specific surface area and semiconducting behavior. Here, we report molecular functionalization of monolayer MoS2 by a square-planar cobalt dithiolene complex. Samples were prepared using a simple immersion-dose procedure followed by rinsing and drying. Confocal Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) establish evidence for electronic coupling to the surface. Raman-active cobalt-ligand stretches are observed that display frequencies up to 35 cm-1 higher than for the free compound. XPS data similarly displays 0.3 eV lower molybdenum and sulfur binding energies along with a new Co 2p signal with 0.2 eV lower binding energy lower than that of the isolated complex. A 1:6 area ratio is determined by XPS using the S 2p region, indicative of a high level of surface functionalization. Atomic force microscopy images confirm large scale functionalization of the MoS2 with an average 2.3 nm increase in step edge height over clean MoS2. This provides a new avenue into studying electronic and catalytic tunability of TMDs.

Molecular functionalization of MoS2 by a cobalt dithiolene complex

256th National Meeting (2018)

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