Preparation of High Concentration Dispersions of Exfoliated MoS2 with Increased Flake Size

By A. O’Neill, U. Khan, Jonathan N. Coleman. 2012

544 citations recorded by the source corpus.

Solvent exfoliation of inorganic layered compounds is likely to be important for a range of applications. However, this method generally gives dispersions of small nanosheets at low concentrations. Here we describe methods, based on sonication of powdered MoS2 in the solvent N-methyl-pyrrolidone, to prepare dispersions with significantly increased lateral nanosheet size and dispersed concentration. We find the concentration to scale linearly with starting MoS2 mass allowing the definition of a yield. This yield can be increased to ∼40% by controlling the sonication time, resulting in concentrations as high as 40 mg/mL. We find the nanosheet size to increase initially with sonication time reaching ∼700 nm (for a concentration of ∼7.5 mg/mL). At longer sonication times the nanosheets size falls off due to sonication induced scission. The nanosheets produced by such methods are relatively thin and have no observable defects. We can separate the dispersed nanosheets by size using controlled centrifugation. Th...

Subfields: Biomedical Engineering, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/821dcb763b5680a2598dd1ed69d1bd5d98101dbd

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Biomedical Engineering

In Materials Chemistry

Citations in the corpus

Few-layer MoS2: a promising layered semiconductor. (2014, background): “cause scission and tearing of the 2D material sheets, reducing their dimensions down to a few thousand nanometers or even smaller.(40,54,178,179,182,184) 186 Small sized MoS2 flakes are not easily utilized for electronic devices that are directly built on them.”
Production and processing of graphene and related materials (2020, background): “more exfoliated material is produced in shorter times, with concentrations in the range of ~1 g l−1 in <24 h for initial bulk material concentrations of 30–50 g l−1) [174, 186, 244].”
Two-dimensional MoS2: Properties, preparation, and applications (2015, methodology): “further optimized this method by carefully controlling the sonication time, resulting in higher reported flake concentration of about 40 mg/mL and relatively increasing flake size [30].”