Evolution of Corrosive Potential‐Induced Degradation at the Rear Side of Bifacial Passivated Emitter and Rear Solar Cells

Detrimental corrosive potential‐induced degradation at the rear side of bifacial solar cells has been found recently. This potential‐induced degradation effect is nonreversible and shows typical surface damages in the micrometer scale. However, also areas in the cells showing no such surface damage suffer from electrical losses. Cracks in the nanometer scale underneath the surface, that is, at the interface between Si bulk and Al 2 O 3 , turn out to be the cause of this effect, leading to depassivation effects. The emergence of these cracks is assumed to originate from oxidation of the Si bulk due to potential‐induced degradation stress.