One Batch Exfoliation and Assembly of Two-Dimensional Transition Metal Dichalcogenide Nanosheets Using Electrophoretic Deposition. Issue 11 (12th August 2015) - Oakes, Landon
Abstract : Two-dimensional (2-D) transition metal dichalcogenides (TMDs) are a family of nanostructures possessing exciting physical properties relevant toward applications often requiring fabrication of macroscopic films and networks. Here, we demonstrate electrophoretic deposition (EPD) for assembly of a broad range of 2-D TMDs, including molybdenum disulfide (MoS2 ), molybdenum diselenide (MoSe2 ), and tungsten disulfide (WS2 ), into uniform coatings that can be universally applied on both planar and porous three-dimensional foam electrodes. This assembly process can be directly coupled with solvent exfoliation to yield one-batch processing capable of transforming bulk TMD powders into functional films and coatings of 2-D TMD nanostructures. EPD from common exfoliating solvents 1-methyl-2-pyrollidone (NMP) and acetonitrile (ACN) indicates assembly kinetics governed by the inherent solution properties of the solvents, with poorer exfoliation in ACN compared to NMP, but more rapid deposition kinetics in ACN compared to NMP. In-situ absorbance monitoring indicates the capability to completely deposit all dispersed mass of highly purified 2-D TMDs onto a solid substrate. Overall, our work demonstrates EPD as a versatile and efficient route to assemble 2-D TMD nanostructures directly from exfoliated dispersions into planar and 3-D substrates for use in diverse applications.