Ag2S nanorice: Hydrothermal synthesis and characterization study

• Rice-shaped Ag2S nanoparticles have been synthesized via a hydrothermal route.
• Pyrrolidone rings of the PVP were involved in the morphology shaping process.
• Ammonia complexation showed deep impacts on morphology control.
• Tip part of the Ag2S nanorice could result in quantum confinement effects.

Silver sulfide (Ag2S) nanorice was synthesized by reaction between silver ammonia complex cation ([Ag(NH3)2]+) and sodium sulfide nonahydrate (Na2S·9H2O) in the presence of polyvinylpyrrolidone (PVP) through a hydrothermal method. The obtained products were characterized by X-ray powder diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FT-IR), ultraviolet–visible spectroscopy (UV–vis) and transmission electron microscopy (TEM). It was found that the as-prepared Ag2S nanocrystal was monoclinic, and the formation of the rice-shaped feature depended mainly on the type of silver source, influence of the pyrrolidone rings of the PVP, reaction time and temperature. Both the remarkable blue shift and the large band gap energy of 4.4 eV revealed that the tip part of the as-prepared Ag2S nanorice could result in quantum confinement effect.