Research on the enhancement of densification and electrical conductivity of silver-coated copper conductive films via oxidation–reduction sintering method

Metal electrodes of crystalline silicon solar cells need to possess good photoelectric conversion properties and play a critical role in converting solar energy into electrical energy, making it particularly important to obtain highly conducive, cost-effective and chemically stable materials. This paper prepared uniformly silver-coated copper powders (Cu@Ag) via electroless plating and a conductive film with low sheet resistance by air oxidation combined with hydrogen reduction sintering (jointly referred to as oxidation–reduction sintering). In addition, the densification mechanism of the Cu@Ag conductive film during sintering was revealed. Results showed that oxidation–reduction sintering promoted the diffusion between Cu and Ag, enhancing the plastic flow of phases and improving the densification of the conductive film. Moreover, the densification of the conducive films was further improved by designing multiple layers. The sheet resistance of the four-layer Cu@Ag conductive film was reduced to 1.5 mΩ/□ at 700 °C, while that of the four-layer Cu@Ag conductive film increased by only 0.6 mΩ/□ at 200 °C after eight days, much more stable than Cu film. This work demonstrates the tremendous potential of oxidation-resistant Cu@Ag conductive pastes in low-cost photovoltaic cells, electronics, and other commercial applications. Graphical