Characteristics of Ag powders coated with Pb-based glass material prepared by spray pyrolysis under various gas environments

Ag powders coated with Pb-based glass material for Si solar cell application are directly prepared by spray pyrolysis in various gas environments. Pb-based glass is successfully formed in the composite powders irrespective of gas environment. The composite powders have bimodal size distributions of nanometer and submicron sizes. However, the number of nano-sized powders decreases when the reducing gas was used as the carrier gas. The silver-conducting films fired at 700 and 800 °C have dense structures without pores irrespective of the gas environment in the preparation of the composite powders. Glass materials are uniformly segregated between micron-sized silver grains. The conducting film formed from the composite powders prepared under 20% H₂/Ar atmosphere have sheet resistance of 7.8, 6.8, 5.1 and 5.9 mΩ/sq at firing temperatures of 500, 600, 700 and 800 °C, respectively.