EFFECT OF SINTERING CONDITIONS ON ELECTRICAL RESISTIVITY OF PRINTED SILVER INKS

Thermal sintering is a simple, cost-effective, and high-throughput option for printed silver inks with nanoparticles. Low-temperature sintering processes are necessary for printed electronics to accommodate substrates or polymer components that cannot withstand high temperatures. However, it is difficult to reach a low level resistivity with printed silver nanoparticles sintered at low temperatures. This study focused on the effect of solvent evaporation during the sintering process and the effect of ligands on the resistivity of the final product. The present investigation used commercial silver ink due to its excellent properties such as low cracking, high uniformity, and good adhesion to the substrate. The solvent was a mixture of propylene glycol monomethyl ether and diethylene glycol monomethyl ether. Thermal gravimetric analysis and differential scanning calorimetry were used to characterize the temperatures of solvent evaporation and ligand decomposition. The resistivities of the sintered silver inks were measured. The study found that preheating was effective in helping achieve lower resistivity and that the removal of ligands could further decrease the resistivity by about 20%.