Ultrasound-Assisted Synthesis of SnS₂ Quantum Dots Using Acetone as Solvent

A sonochemical synthesis of SnS₂ quantum dots using acetone as a solvent is investigated. Two different tin sources (SnCl₂∙2H₂O or SnCl₄∙5H₂O) as well as two different sulfur sources (thioacetamide or Na₂S₂O₃) were applied. The sonication time was also varied between 60 and 120 min. Resulting products of syntheses were characterized with the following techniques: powder X-ray diffraction, electron microscopy (SEM and HR-TEM), Raman and FT-IR spectroscopies, the Tauc method, and X-ray photoelectron spectroscopy. Obtained SnS₂ nanostructures were in the form of quantum dots in the case of synthesis lasting 60 min (size of crystallites in the range of 3.5-7 nm) and in the form of elongated nanorods of length ca. 25-30 nm and width of 5-6 nm in the case of synthesis lasting 120 min. XPS analyses revealed that the surface of the obtained products contained a significant amount of tin at the second oxidation state (i.e., SnS). The quantum dots produced in the synthesis lasting 60 min showed a value of energy bandgap of 2.7 eV indicating potential applications in photocatalysis.