Inkjet printable silver dispersions: Effect of bimodal particle-size distribution on film formation and electrical conductivity

Inks containing silver nanoparticles of 12 nm, 80 nm, and a 15%/85% mixture of the two sizes were used to evaluate the effect of particle size and size distribution on the electrical properties of sintered films. The silver layers deposited with a “drop-on-demand” inkjet printer were heated at temperatures ranging from 125 to 200 °C. The small particles formed less resistive films at 125 °C, while the larger ones provided better electrical conductivity above 150 °C. The inks containing mixed small and large particles yielded the most conductive silver films over the entire investigated temperature range. A mechanism explaining these results is proposed based on the evolution of film microstructure with temperature.