Sonochemical synthesis of silver nanoparticles coated copper wire for low-temperature solid state bonding on silicon substrate

Silver nanoparticles (AgNPs) are directly grown on surface of ~25 μm copper wire by ultrasound-assisted chemical reduction. Silver nitrate is used as precursors, when polyvinylpyrrolidone (PVP) is added as a controller of the dimension of AgNPs. Influence of growth parameters such as precursor's concentration, ratio proportion of PVP and ultra-sonication on the growth of AgNPs coating are determined. The best morphology, size of the AgNPs are observed on copper wire. The results show that the copper wire coated with AgNPs of~100 nm diameter exhibits good antioxidation and ohmic contact after sinter on Si substrate at a temperature as low as 320℃, is especially suitable as a substitute for silver paste electrode used in silicon solar cells.