The Effect of Stabilizer and Particle Size on the Conductivity of Silver Patterns

Abstract

As recent trends of flexibility for electronics, the interest on various silver pastes with higher quality has been increased more and more. In this paper, conductive silver pastes were prepared with silver nanoparticles (Ag-NPs) which were synthesized by chemical reduction process. Ag-NPs were obtained with silver salts and short-chain alkylamine such as hexylamine, octylamine, and decylamine. The resulting Ag-NPs had an average diameter of 9 nm, 86 nm, and 148 nm, respectively, containing 4.5 %, 3.1 %, and 1.1 % of residual organics, which made them possible to disperse in organic solvents such as α-terpineol. A silver paste with a solids content of about 50 wt. % was prepared by dispersing the Ag-NPs in terpineol with acrylic resin, photoinitiator, and additives. Silver neodecanoate (Ag-ND) complex was added to silver paste, for the purpose of increasing stability of dispersion. And silver films were patterned by screen printing on PU coated PET substrates. Silver films were irradiated by ultraviolet (UV) light for 10 minutes at about 45 ˚C. The conductivity of silver film was improved by thermal sintering at 200 ˚C for 10 minutes. After thermal sintering, the resistivity was decreased under the 5.0 × 10¹ μΩ/cm.