Minimizing the Polarization-Type Potential-Induced Degradation in PV Modules by Modification of the Dielectric Antireflection and Passivation Stack

Potential-induced degradation in n-type modules is typically associated with a surface polarization effect. This paper shows that modifications at the cell level can minimize the potential-induced degradation of modules caused by a polarization effect. As is demonstrated on n-PERT cells, the potential-induced degradation can be reduced effectively by modification of the silicon nitride antireflection coating. Potential-induced degradation tests on mini-modules confirmed the predictions by the stipulated polarization-type potential-induced degradationmodel that the potential-induced degradation is minimized when an Si-rich, conductive layer with refractive index n = 2.4 is inserted between the wafer and the outer SiNx layer with refractive index n = 2.0. In this way, the optical and passivation properties of the cell are maintained. The proposed modifications are easy to implement in the manufacturing process and are therefore cost-effective.