Effect of stabilizing agent on the morphology and optical properties of silver nanoparticles

Silver nanoparticles (AgNPs) were prepared in different sizes and forms by reduction of AgNO3 using sodium borohydride as a reducing agent and different concentrations of dodecanethiol (DDT) as a stabilizing agent. The morphology and particle size were studied by Transmission Electron Microscopy (TEM) and the results showed that different sizes of AgNPs were formed. The particle size was controlled by changing the ratio between AgNO3 and (DDT) in the presence of NaBH4. Appearance of surface Plasmon band in the ultraviolet–visible spectra (420–445 nm) was due to the formation of AgNPs in different sizes. The data of FTIR and X-ray diffraction confirm that the DDT molecules have coordinated to the surface of Nano-Ag particles through their head-groups. AgNPs were synthesized from a large enough concentration of DDT and had a very small grain size. It was supposed that the surface-capped AgNPs prohibits significantly increased stability and dispersibility.