Highly concentrated MoS2 nanosheets in water achieved by thioglycolic acid as stabilizer and used as biomarkers†
Abstract
In this work, we reported the synthesis of water soluble MoS2 quantum dots from the monolayer nanosheets of MoS2, using thioglycolic acid (TGA) with a sonication method. The gaps between the MoS2 layers were enlarged by the stirring process. Meanwhile TGA molecules strongly binding to the defect sites of MoS2 would reduce the van der Waals force between the MoS2 layers through sonication. This led to the improved dispersion of MoS2 monolayers in water. The addition of TGA molecules not only exfoliated the bulk of MoS2, but also modified the surface of MoS2 with carboxylic acid groups. As a result, highly concentrated MoS2 nanosheets were produced in water. Subsequently, heavy metal-free MoS2 quantum dots with sustained fluorescence emission, which were fabricated from hydrothermal treatment of MoS2 monolayers, can be utilized as cell biomarkers.