Conductive Paste Inks Prepared Using Ionic-Liquid-Stabilized Metal Nanoparticle Fluids and their Sintering Effect

Conductive paste inks have received considerable attention as facile conductive materials for the formation of electrode layers. However, conventional paste inks result in films with poor surface morphology. In addition, they require a high thermal annealing temperature for achieving high electrical conductivity because of their organic/inorganic composite structure, in which nanosized metal particles and polymeric organic binders are mixed in solvents. In this work, we prepare solvent-free and polymeric-binder-free metal nanoparticle (NP) fluids, which can be used as facile conductive pastes for forming an electrode layer after sintering at a considerably low temperature. We employ thiol-terminated imidazolium-type ionic liquid (IL-SH) molecules with a small molecular weight and fluidic behavior as the surface ligands of Ag NPs. IL-SH-stabilized Ag NPs exhibit fluidic behavior and metallic conducting properties at a considerably low sintering temperature of 250 °C. Graphical Abstract: (Figure presented.)