Dependency of silver nanoparticles protective layers on sintering temperature of printed conductive structures

Flexible electronics, which actual cover a significant part of electronic market, requires as low processing temperature as possible. Plastic foil type of substrates needs specific conditions for using it as a base of electronic circuits. For the practical production of printed electronics, one of important requirements is design the special type of inks with good printability and stability during printing conditions. Such inks should be easy to print, have to contain a high amount of silver and need relatively low 150°C sintering temperature. Silver metallic nanoparticles are the most popular conductive fillers for ink-jet printing application [1]. As is known, nanosized silver does not exist without protection layer around each particles. Nanosilver must be encapsulated by a protective shell of organic dispersants to avoid aggregation. When the metallic nanoparticle inks are heated, the dispersants should be effectively removed, allowing the remaining nanoparticles to be successfully sintered [2]. For such a case the most promising type of protective layer on Ag nanoparticles will be layer which should be removed in temperature not higher than 150°C. In the current paper several types of nanosilver with different polymer, carboxylate and amine type coating shells were described. Parameters of received nanonsilver and the results of the dynamics of removing the protective coating as a function of temperature and time were presented. We also made attempts to suspend our prepared nanosilver in inks medium as conductive fillers.