The Effect of Ag Powder Surface Topography on the Viscoelastic Behavior of Thick-Film Ag Gridlines and Solar Cell Performance

The effect of silver powder surface topography is studied for screen-printed gridlines. For front-side solar cell metallization with Ag powders that have surface corrugations the thick-film viscoelastic recovery is improved. This resulted in a higher aspect-ratio of 0.38 for the gridlines with corrugatedsurface Ag powders compared with an aspect-ratio of 0.28 for gridlines with smoother-surface Ag powders. Moreover, dimensional variations are mitigated for gridlines with corrugated-surface Ag powders compared with gridlines having smoother-surface Ag powders. This led to a photocurrent enhancement, resulting in ~0.1 % absolute median efficiency improvement for c-Si solar cells having gridlines with corrugatedsurface Ag powders.