Synthesis And Research Of Silver Sulfide Nanocolloids

Nano semiconductor materials have significant potential for applications in thenonlinear optics, catalysis, medicine, magnetic media, functional materials, because oftheir quantum size effect, surface effect and macroscopic quantum tunneling effect.Among the semiconductor materials, the unique optical and optoelectronic propertiesof silver sulfide (Ag2S) nanoparticles made it have important application value insensor, catalysis, absorption and other fields. So the preparation of silver sulfidenanoparticles has become a hot research field. In recent years, the preparationtechnology of silver sulfide nanoparticles has a rapid development. However, findingsimple and rapid ways to synthesis of monodisperse silver sulfide nanoparticles withdifferent morphologies would become an important trend.In this paper, silver sulfide nanoparticles with hollow sphere-shape andrice-shape were synthesized in aqueous solution by adjusting the prepared method, thetype and concentration of silver source and sulfur source, complexing agent,protecting agent and reaction time and so on. The synthesized silver sulfidenanoparticles were characterized by X-ray diffraction, transmission electronmicroscopy, high resolution transmission electron microscopy, scanning electronmicroscopy, laser particle size analyzer, UV-vis spectroscopy and Fourier transforminfrared measurements.Firstly, the silver sulfide nanoparticles were synthesized by the liquid-phasesynthesis method at room temperature in aqueous solution. Secondly, the influencesof reaction parameters (the type and concentration of silver source, sulfur source,complexing agent, protecting agent and reaction time) on experiment results werediscussed in detail. Results showed that, the type of silver sources and sulfur sourceshave a close relationship with the formation of hollow nanosphere. Silver sulfidehollow nanospheres with an average length of about35nm has been synthesized atroom temperature just in0.5h using silver laurate(0.01mol/L) and thiourea(0.02mol/L) as raw materials, n-butylamine(1mL) as complexing agent,polyvinylpyrrolidone as protecting agent. The hollow structure of silver sulfidenanoparticles lend to a clear quantum confinement effect, which was testified by thelarge band gap energy of3.8eV. Based on previous work, silver sulfide nanoparticles were synthesized byhydrothermal method. The influences of reaction parameters on the products wereinvestigated. It was found that the formation of the rice-shape featured Ag2Snanoparticles depended mainly on the properties of sulfur source, the type andconcentration of sulfur source, complexing agent, protecting agent. Silver sulfidenanorice with an average length of about30nm has been synthesized at120?for10h, using silver laurate(0.01mol/L) and sodium sulfide(0.02mol/L) as rawmaterials, n-butylamine(1mL) as complexing agent, polyvinylpyrrolidone asprotecting agent. Compared with bulk silver sulfide, the obtained silver sulfidenanorice showed clear quantum confinement effect, which was testified by there-markable blue shift of its UV-visible absorption edge and the large band gapenergy of4.4eV.