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

Inks containing silver nanoparticles of 12 nm, 80 urn. 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 ink Jet printer were heated at temperatures ranging from 125 to 200 degrees C. The small particles formed less resistive films at 125 degrees C, while the larger ones provided better electrical conductivity above 150 degrees 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.