A new 2-methylimidazole-assisted liquid-exfoliation method for a rapid scalable fabrication of chemically pure MoS2 nanosheets

A new liquid exfoliation method of pristine MoS2 in a hot solution of 2-methylimidazole for a rapid fabrication of 1–2 nm-thick MoS2 nanoflakes is developed. The method makes it possible to produce large amounts of stable MoS2 hydrosols with concentrations 0.21–0.53 mg/ml within 2–4 h. Energy-dispersive X-ray spectroscopies and thermogravimetric analysis confirmed chemical purity of MoS2 after the removal of 2-methylimidazole with water. The as-formed MoS2 nanoflakes have a relatively narrow size distribution (50 ± 25 nm) and exhibit a strong aggregation-dependent luminescence at 420–475 nm. The thin films obtained from the MoS2 nanoflakes by spin-coating possess good semiconductor properties showing a non-ohmic linear current-voltage dependence and a surface resistivity up to 7.9 × 10–2 Ω·сm. The reported method may provide an affordable, experimentally simple and ecology-friendly alternative to commonly used techniques for fabricating MoS2 nanosheets with a potentially useful combination of size and properties for further applications in hybrid and composite materials.