Redox Liquid Phase Exfoliation of Layered Transition Metal Dichalcogenides (Postprint)

Layered transition metal dichalcogenides TMDs are an emerging class of 2-dimensional materials due to their diverse property suite, which range from semiconducting and semimetallic to metallic and superconducting.1 Their lamellar structure consists of a transition metal layer M sandwiched between two chalcogen layers X with strong M-X intralayer bonding. These layers are separated by a weak van der waals gap. At the few- to mono-layer limit, coupling between layers is reduced, in-plane confinement dominates, and the band structure changes. This affords unique opportunities for chemical sensing, catalysis, spintronics, single-photon emission, infrared optics, nanocomposites, coatings, and printable inks for nanoelectronics.25 Thus, a suite of processing methods have evolved to satisfy application-specific requirements, such as defect density, scale, cost, and integration. Top-down exfoliation of powders affords large volume use and compliments molecular-based monolayer growth for micro-fabricated devices.