A novel Ag nanoparticles purification method and the conductive ink based on the purified Ag nanoparticles for printed electronics

In this study, a novel method called membrane separation–centrifugation technology is used to purify the AgNPs. The TGA results showed that the AgNPs washed in this method only contained a minimal amount of organic residues (< 5 wt.%). Moreover, the XRD results indicate that the cleaned AgNPs are pure single-crystal cubic phase Ag without other impurities. Furthermore, according to the results of SEM and TEM, the AgNPs cleaned by this technology are nanoscale with an average particle size of only 50 nm and dispersed evenly without agglomeration. The colloid made from AgNPs purified by this method reveals a good Zeta potential of about -34.7 mV, which indicates the excellent stability of AgNPs. After the ink made by these AgNPs is dried at 150℃ for 10 min, a really low electrical resistivity only about 10.7 × 10 –6 Ω·cm is obtained. These results confirm that the membrane separation–centrifugation technology can significantly improve the performances of the AgNPs ink, which can be used in printed electronics.