Strongly luminescent monolayered MoS2 prepared by effective ultrasound exfoliation

Abstract

Intense ultrasound in a pressurized batch reactor was used for preparation of monolayered MoS₂nanosheets from natural mineral molybdenite. Exfoliation of bulk MoS₂ using ultrasound is an attractive route to large-scale preparation of monolayered crystals. To evaluate the quality of delamination, methods like X-ray diffraction, Raman spectroscopy and microscopic techniques (TEM and AFM) were employed. From single- or few-layered products obtained from intense sonication, MoS₂quantum dots (MoSQDs) were prepared by a one-pot reaction by refluxing exfoliated nanosheets of MoS₂ in ethylene glycol under atmospheric pressure. The synthesised MoSQDs were characterised by photoluminescence spectroscopy and laser-scattering particle size analysis. Our easy preparation leads to very strongly green luminescing quantum dots.