Universal Approach towards 2D van der Waals Metal Chalcogenides from Molecular Building Blocks for Device Application

Layered materials beyond omnipresent graphene such as chalcogenide-based materials that possess tunable and defined crystallographic structures and elemental compositions offer a broad portfolio of potential applications in sensors, detectors, and energy storage devices. The lacking control of large scale and homogeneous formation of 2D layered materials MX₂ (X = S, Se) in commercial formation processes motivated us to develop a unique synthetic approach to layered 2D materials. Complete characterization of synthesized complexes enabled their controlled decomposition to desired materials.<br/>Herein we report a uniform synthesis of molecular building blocks to form (air)stable precursor classes [M{S(C₂H₄)₂NMe}_x] (M = Mo^IV, W^IV, Ti^IV, Zr^IV, Hf^IV, Nb^IV, Ta^IV, Sn^IV, x = 2; M = Ge^II, Sn^II, x = 1), which reliably delivered layered 2D <i>van der Waals</i> heterostructures.<br/>Following a simple synthetic protocol, the reaction of tridentate SNS donor ligand with suitable metal compounds resulted in (air)stable molecular precursors, which have been characterized on an atomic scale. These precursors enabled the formation of homogeneous crystalline layered chalcogenide based heterostructures by thermal decomposition MoS₂, WS₂, TiS₂, SnS/Se₂, SnS/Se. These molecular building blocks provide an extraordinary synthetic pathway to a unique molecular precursor class, which delivered viable approach for large scale synthesis to chalcogenide-based <i>van der Waals</i>materials for application in novel electronics, optics, and photonic devices.