Synthesis of blue photoluminescent WS2 quantum dots via ultrasonic cavitation

Blue photoluminescent WS 2 quantum dots (QDs) were synthesized using a simple top-down method from natural raw mineral tungsten disulfide via tip ultrasonication followed by centrifugation in a water-ethanol (0.7/0.3 ratio) as eco-friendly solvent. Cavitation process at a high power (300   W) led to the breaking of bulk WS 2 flakes to its quantum dots. The as synthesized WS 2 QDs showed blue photoluminescence upon UV excitation. The synthesized WS 2 QDs were analysed by UV–vis and photoluminescence spectrophotometry , transmission electron microscopy , atomic force microscopy and X-ray diffraction. According to the transmission electron microscopy images, the size of WS 2 QDs was obtained as 5   nm in average.