Improved dispersant-free liquid exfoliation down to the graphene-like state of solvent-free mechanochemically delaminated bulk MoS2

Abstract

Molybdenum disulfide (MoS2) was recently found to exhibit an indirect-to-direct gap transition when its thickness is reduced to a single S–Mo–S trilayer sheet, which opens up opportunities for a range of novel optoelectronic applications. Here we first report the possibility of dispersant-free efficient liquid exfoliation down to the graphene-like state of solvent-free mechanochemically delaminated bulk MoS2. The graphene-like, single-sheet structure of MoS2 nanoparticles in the dispersions is confirmed by mutually complementary experimental methods. The proposed approach essentially improves the known liquid exfoliation method based on the ultrasound disintegration of bulk MoS2, because the proposed mechanochemical treatment of the initial bulk MoS2 could provide 100% yield of the single-sheet nanoparticles without the use of dispersants.