An investigation on determinants of silver paste metallization contact performance on crystalline silicon solar cells

Since the application of silver (Ag) electrodes is of vital importance to the power output of crystalline silicon (c-Si) solar cells, the factors affecting Ag paste metallization contact performance on Si wafers need to get well understood. Herein, the correlation of Ag/Si contact resistivity and glasses used in Ag paste was studied comprehensively. Here taken for exemplification are three types of glass samples used in Ag paste, because the application of them can result in obvious differences in the contact interface characteristics as well as in the contact resistivity. It was found that the factors affecting contact resistivity include the formation of Ag colloids in the glass phase, the doping concentration in the contacted Si surface, and the fixed charge density and defect states density at the interface. In terms of these issues, the key functions and mechanisms of glasses used in Ag paste are elucidated, and also their effects on electrical performance of cells are discussed in this article.