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.

We present the effect of the reducing agent (sodium borohydride) and stabilizing agent (dodecanethiol) on the sizes and shapes of AgNPs using TEM, UV–vis, X-ray and FTIR techniques .Figure optionsDownload as PowerPoint slideHighlights
► Silver nanoparticles were synthesized in the range 2.4–16.6 nm.
► Effect of dodecanethiol (DDT) and sodium borohydride ratios on the size was studied.
► The change of the surface plasmon band with particle size was confirmed.
► The coordination of the stabilizing agent with the surface of Nano-Ag particles was clarified.