UV-induced degradation of PERC solar modules with UV-transparent encapsulation materials

In this paper, we report on the stability of p-type passivated emitter and rear cells under ultraviolet (UV) exposure with various silicone nitride passivation coatings and embedded in different encapsulation polymers. Our results reveal that UV transparent polymers can result in a module power loss of up to 6% under a UV irradiation dose of 497 kWh/m2. We show that the degradation in power is caused by a reduction in open circuit voltage. This loss is related to an increased recombination in the cell, which we ascribe to a degradation of the surface passivation. With ray tracing simulations, we determine the number of photons reaching the passivation interface. Assuming that all photons with energies above 3.5 eV de-passivate the interface is in agreement with our experimental results. Copyright © 2017 John Wiley & Sons, Ltd.