Plasma Synthesis of Silver Nanoparticles in Ionic Liquid: An Analysis on the Effects of Concentration, Reaction Time, and Plasma Parameters on the Size and Morphology of Silver Nanoparticles

The aim of this research is to create silver nanoparticles (Ag NPs) directly in an ionic liquid (IL) using a DC plasma source and to understand the effects of polarity of the plasma source, concentration of silver salt in the IL, plasma current, and reaction time on the size and shape of the synthesized Ag NPs. ILs are salts that are liquid below 100℃, have low vapor pressure, low toxicity, and are able to provide stabilization for Ag NPs, eliminating the need for other capping and stabilizing agents. To synthesize the nanoparticles, we mix silver salt (AgBF4) into the IL, [BMIM][BF4], which is then exposed to the DC plasma source in a vacuum chamber. Reactive species in the plasma reduce silver ions in the solution, thereby creating neutral silver atoms that coalesce and form Ag NPs. The size and shape of Ag NPs after synthesis were measured using scanning electron microscopy and UV-Visible absorption spectroscopy. Results show that plasma synthesis under various conditions creates Ag NPs with diameters ranging from 10-200 nm. In this work, we present the effects of these different conditions on resulting nanoparticle size.