Large-scale synthesis of polyhedral Ag nanoparticles for printed electronics

Printed electronics mainly use ink that contains silver with a high weight fraction to print conductive patterns. The synthesis of polyhedral Ag nanoparticles has been previously reported for lab-scale batches with a low weight fraction. The clean synthesis of large batches with homogeneous size and shape and high-volume fraction and conductivity is still challenging. Here, we report an original pathway to yield large batches of high weight fraction (typically 60 g of 50 wt% ink). The synthetic route goes through the formation of Ag₂O, which is then reduced by H₂O₂ in the presence of a stabilizing polymer. The mechanism is discussed in view of the phase and composition analysis of the samples during the reaction. After printing lines of Ag NPs, the electrical properties of the Ag lines were measured, and the results are discussed along with the microstructure. The electrical resistivity reached values as low as 6.6 times the bulk value after mild annealing at 200 °C for 45 minutes.