Dispersion behavior of two dimensional monochalcogenides.

Solution processable two-dimensional (2D) materials have provided an ideal platform for both fundamental studies and wearable electronic applications. Apart from graphene and 2D dichalcogenides, IVA-VI monochalcogenides (MMCs) has emerged recently as a promising candidate for next generation electronic applications. However, the dispersion behavior, which is crucial for the quality, solubility and stability of MMCs, has been quite unexplored. Here, the exfoliation and the dispersion behavior of Germanium (II) monosulfide (GeS) and Tin (II) monosulfide (SnS) nanosheets has been investigated in a wide range of organic solvents. Nine different organic solvents were examined and analyzed, considering the solvent polarity, surface tension, and Hansen solubility parameters. A significant yield of isolated GeS and SnS flakes, namely ~16.4 and ~23.08 {\mu}g/ml in 2-propanol and N-Methyl-2-pyrrolidone respectively were attained. The isolated flakes are few-layers nanosheets with lateral sizes over a few hundreds of nanometers. The MMCs colloids exhibit long-term stability, suggesting the MMCs applicability for scalable solution processable printed electronic device applications.