Laser induced forward transfer of Ag nanoparticles ink deposition and characterization

In this work, we report on the printing of silver nanoparticles (Ag NPs) ink by means of laser-induced forward transfer (LIFT) process. The optimum conditions for printing circular shaped features using a Nd:YAG laser at 266 nm have been examined. A study of the influence of the laser fluence and the use of a pre-coated intermediate layer (sacrificial layer) on the donor substrate was performed in order to understand how these parameters affect the printed droplets morphology. We also provide a detailed discussion of the influence of the annealing temperature on the printed features morphology and on their resistivity. Based on these results, the conditions have been determined for printing uniform circular shaped droplets with a diameter as small as 25 μm and an average thickness of 150 nm. Atomic force microscopy on the cured printed droplets revealed a uniform surface morphology with no coffee ring effect. Finally, conductive features with reasonably low resistivity (approximately eleven times that of bulk silver) and at sufficiently low sintering temperatures (100-150 °C) were produced on silicon oxide on silicon and flexible polyimide substrates.