Kinetics of the Light and Elevated Temperature Induced Degradation and Regeneration of Quasi-Monocrystalline Silicon Solar Cells
We investigate the degradation and regeneration behavior of quasi-monocrystalline silicon passivated emitter and rear cells under illumination at elevated temperatures. The decrease and increase of the solar cell efficiencies over time is accelerated under increased temperature or illumination intensity. We examine the defect activation kinetics and determine rate constants both for the degradation and regeneration. We apply temperatures in the range of 37-140 °C and illumination intensities in the range of 0.1-1.4 suns. These conditions typically occur when operating solar modules in the field. The rate constants are strongly increased with increasing temperature and increasing illumination intensity. We perform multiple regressions fits of the degradation and regeneration data with different approaches for the illumination intensity dependence. A linear illumination intensity dependence on the rates of degradation and regeneration is found. Activation energies for the degradation and regeneration of (0.89 ± 0.04) eV and (1.07 ± 0.07) eV, respectively, are extracted that allow for identification of the defect activation and deactivation mechanisms.