Synthesis and Characterization of ZnS: Ag Nanocrystals Surface-capped with Thiourea1

Ag+-doped ZnS nanocrystals surface-capped with thiourea (expressed as ZnS: Ag/thiourea) were synthesized through sol-gel method with thiourea as a surface modifier and characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), X-ray fluorescence spectrum (XRF), infrared spectrum (IR), UV-Vis absorption spectrum(UV-Vis), and photoluminescence spectrum (PL). The results show that Ag+ ions are doped in ZnS nanocrys-tals, and the sulfur atoms in thiourea molecules coordinate with metal ions on the surface of the nanocrystals. The spherical ZnS: Ag/thiourea nanocrystals with an average diameter of 5 nm have good fluorescent characteristics, and therefore have great potential for use in molecular assembly and novel luminescence materials.