Microwave-assisted synthesis of WS₂ nanowires through tetrathiotungstate precursors

Tungsten disulfide (WS₂) nanowires have been synthesized through a microwave-assisted chemical route that uses tungstic acid, elemental sulfur and monoethanolamine as starting reagents for obtaining a precursor solution of tetrathiotungstate ions. Acidification of the precursor solution yields amorphous precipitates, which lead to the formation of nanowires of WS₂ with thickness of about 5-10 nm when heated at 750 °C under argon atmosphere for 1.5 h. Phase and the microstructure of the prepared powders have been investigated through x-ray powder diffraction and high-resolution transmission electron microscopy, respectively. Optical absorption of the WS₂ powders reveals a red shift of the exciton bands compared to bulk WS₂.