Synthesis of blue photoluminescent WS2 quantum dots via ultrasonic cavitation

Blue photoluminescent WS2 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 WS2 flakes to its quantum dots. The as synthesized WS2 QDs showed blue photoluminescence upon UV excitation. The synthesized WS2 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 WS2 QDs was obtained as 5 nm in average.