Chemical sintering of Ag nanoparticle conductive inks at room temperature for printable electronics

Silver (Ag) nanoparticles with a mean diameter of about 24.3 nm were synthesized by electroless deposition in an aqueous solution using PAA-Na and ascorbic acid as protective and reducing agents, respectively. The Ag nanoparticles were utilized as conductive ink and sintered at room temperature using different halide solutions (NaCl, NaBr, NaI, LiCl, KCl) at varying concentrations. A significant increase in particle size of about 174–990% was observed after sintering depending on the type of halide solution used. This also led to an increase in the electrical conductivity of the printed Ag pattern. Halide solutions with smaller ionic sizes generally promote the fusing of Ag nanoparticles, which results in larger Ag particles (NaCl > NaBr > NaI) and higher electrical conductivity. The use of an ionic stabilizer (PAA-Na salt) is more effective as a capping agent for Ag nanoparticles. Sintering is also more significant in samples stabilized by PAA-Na compared to those with PAA only.