Two-Dimensional Nanosheets by Rapid and Efficient Microwave Exfoliation of Layered Materials

Layered materials beyond graphene have generated renewed interests in numerous fields. Liquid-phase exfoliation methods face essential challenges in their universal application toward various two-dimensional materials (2DMs), short processing time, high yield, chemical stability, ultrathin thickness, and large lateral size of the nanosheets. To date, few reported methods are satisfactory in these requirements. We develop a general microwave-assisted, rapid (30 min), efficient (up to 50% yield), and potentially scalable approach to exfoliate 2DMs into mono- and few-layer nanosheets of superior chemical stability and large lateral size. 2DMs including h-BN, g-C3N4, BP, TMDs (MoS2, WS2, MoSe2), Zn2(bim)4, and Ti3C2Tx are tested for exfoliation in different fluid media including organic solvents and PF6–-containing ionic liquids (ILs). The nanosheets (e.g., BP) are surprisingly stable, probably attributed to solvation shells preventing the exfoliated sheets from reacting with water and oxygen. Theoretical sim...