Synthesis of Indium(III) Sulfide by The Chemical Precipitation Method

In this study, indium sulfide (In₂S₃) nanostructures were successfully synthesized via a chemical precipitation method using indium chloride (InCl₃) and elemental sulfur in an alkaline medium. Tartaric acid was employed as a complexing agent to stabilize indium (III) ions and prevent their hydrolysis over a wide pH range. The synthesis was carried out at pH 10–11, resulting in a brown precipitate, which was identified as In₂S₃ by various physicochemical analyses. Thermogravimetric analysis (TGA) revealed a total mass loss of 18.52 mg upon heating from 293 K to 1023 K, corresponding to the oxidation of In₂S₃ to In₂O₃. The experimentally determined mass ratio of indium to sulfur (59.03:40.97) was consistent with the stoichiometry of In₂S₃. Elemental analysis confirmed the close match between theoretical and experimental values of indium and sulfur content. X-ray diffraction (XRD) analysis indicated that the synthesized material crystallized in a tetragonal structure with lattice parameters a = 4.012 Å and c = 39.21 Å. Scanning electron microscopy (SEM) images revealed that the product consisted of nanorods with diameters ranging from 173 to 261 nm. The combined results confirm that the synthesized compound corresponds to stoichiometric In₂S₃ with well-defined nanostructured morphology, making it a promising candidate for optoelectronic and semiconductor applications.