Impact of surface passivation on UV stability of bifacial mc-Si PERC solar modules

Many research show that UV degrades the solar cell and module power. In this work, we study the UV stability of mc-Si bifacial PERC solar modules with different industrial silicon nitride (SiNx) passivation. We find that with exposure to UV at 60 °C, both VOC and JSC decrease then stabilize. The quantum efficiency analysis shows decreased response in both short (blue loss) and long (base collection loss) wavelength range. It infers that deteriorations were not only at passivation layers, but also in the silicon bulk, caused by UV-induced degradation and possible LeTID. No significant difference in degradation has been found between front and rear passivation, or between different PECVD, respectively. While thermal oxidation process employed in mass production effectively improved UV resistance.