Non-aqueous synthesis of silver nanoparticles using tin acetate as a reducing agent for the conductive ink formulation in printed electronics

We have developed a process for the synthesis of silver nanoparticles protected with a passivating shell of dodecylamine in toluene media using tin(ii) acetate as a reducing agent. Based on the electrochemical series, during the reduction process Sn(ii) oxidizes into Sn(iv) which reduces Ag(i) into Ag(0). The nucleation and growth processes result in particles with diameters in the range 5-20 nm. This simple non-aqueous one pot synthesis can be easily scaled up to produce grams of nanoparticles in a matter of hours. The particles can also be dispersed in many non-aqueous solvents which make them a suitable candidate for many applications. Characterization of the end product using TEM, UV-Vis spectroscopy, and powder X-ray diffraction verified the presence of a silver metallic core whereas TGA confirmed the presence of a dodecylamine shell. The resulting particles were used in non-aqueous conductive ink formulation. The ink was used to print conductive tracks on flexible substrates like Epson photo paper and polyimide (Kapton) using an Aerosol Jet based printing technique.