One-Step Synthesis of Transition Metal Dichalcogenide Quantum Dots Using Only Alcohol Solvents for Indoor-Light Photocatalytic Antibacterial Activity

In this study, we report a one-step direct synthesis of molybdenum disulfide (MoS) and tungsten disulfide (WS) quantum dots (QDs) through a solvothermal reaction using only alcohol solvents and efficient () decompositions as photocatalytic antibacterial agents under visible light irradiation. The solvothermal reaction gives the scission of molybdenum-sulfur (Mo-S) and tungsten-sulfur (W-S) bonding during the synthesis of MoS and WS QDs. Using only alcohol solvent does not require a residue purification process necessary for metal intercalation. As the number of the CH groups of alcohol solvents among ethyl, isopropyl, and ()-butyl alcohols increases, the dispersibility of MoS/WS increases. The CH groups of alcohols minimize the surface energy, leading to the effective exfoliation and disintegration of the bulk under heat and pressure. The bulky -butyl alcohol with the highest number of methyl groups shows the highest exfoliation and yield. MoS QDs with a lateral size of about 2.5 nm and WS QDs of about 10 nm are prepared, exhibiting a strong blue luminescence under 365 nm ultraviolet (UV) light irradiation. Their heights are 0.68-3 and 0.72-5 nm, corresponding to a few layers of MoS and WS, respectively. They offer a highly efficient performance in sterilizing as the visible-light-driven photocatalyst.