New insight into the size-controlled synthesis of silver nanoparticles and its superiority in room temperature sintering

Abstract

For the better application of room-temperature sintering in printed electronics, a low-cost and convenient approach to synthesize size-controlled silver nanoparticles (Ag NPs) ca. 37 nm in average diameter is presented. Monodisperse Ag NPs with a narrow size distribution were rapidly and routinely produced on relatively large scales through a typical polyol process using poly(vinyl pyrrolidone) (PVP) as the capping agent and poly(ethylene glycol) (PEG) to enhance the reducibility and viscosity of solvent. These Ag NPs would suffer a spontaneous sintering, which was triggered by the desorption of PVP from their surface, when they encountered a certain amount of Cl⁻; the eventual coalescence and Ostwald ripening processes would make their structure more compact and solid, leading to a high conductivity even up to 40% that of bulk silver.