Mechanism of silver/glass interaction in the metallization of crystalline silicon solar cells

In order to reveal the interaction between solid substances (Ag powder and glass frit) during the metallization of crystalline silicon solar cells, the effect of glass frit on the Ag powder sintering and the mechanism of Ag colloid formation in glass phase were investigated. The results show that the Ag powder could grow into larger grains as mixed with a certain amount of glass frit, because the corrosion of Ag by glass melt enabled early start of Ag sintering. This makes the internal grain size and electric resistivity of sintered Ag lines to be closely related to the glass content in the silver paste. Subsequently, it was found that the formation of Ag colloid in glass phase is a physical process rather than a chemical transformation process. Taking Pb-B-Zn-Al composite oxide glasses for exemplification, a feasible strategy of raising the solubility of Ag in glass melt is proposed.