Anion-mediated synthesis of monodisperse silver nanoparticles useful for screen printing of high-conductivity patterns on flexible substrates for printed electronics

Monodisperse silver nanoparticles (NPs) have been synthesized on a large scale by oxidation-reduction reactions in water by adding triethylamine to the aqueous solutions of AgNO3, glucose and poly(vinyl pyrrolidone). Different anions, including -SO42-, -PO43-, -CO32- and -Br-, are introduced to the above mentioned mixture to form slightly soluble silver compounds, which are used as the precursor to synthesize silver NPs. The effects of silver nitrate-glucose ratio and reaction temperature are investigated. The electrical performance of the as-obtained Ag NPs has been studied, and the results reveal that the -CO32- mediated-synthesized Ag NPs possess the lowest resistivity. Note that silver NPs can be well-dispersed in ethanol and generated as inks, which can be screen printed onto flexible polyester (PET) and paper substrates and form conductive patterns after a low-temperature sintering treatment. An optimal electrical resistivity can be reached at 5.72 mu Omega cm, which is much closer to the value of bulk silver (1.6 mu Omega cm). Evidently, the synthesized silver NPs could be considered as low-cost and effective materials that have a great potential application for flexible printed electronics.