Modulation of carrier‐induced defect kinetics in multi‐crystalline silicon PERC cells through dark annealing

In this letter, we report on significant changes caused after dark annealing to the kinetics of the carrier‐induced defect, present in p‐type multi‐crystalline silicon PERC cells. The characteristic shapes of the degradation and regeneration curves under light soaking at 75 °C are dramatically altered, depending on the temperature of an initial dark anneal on the non‐degraded cell. Dark annealing for a fixed time (2.5 h) at temperatures of 200 °C or below, is found to accelerate both the subsequent degradation and regeneration rate and the degradation severity, while at higher temperatures it appears that a possible second defect with a significantly longer degradation and regeneration rate is activated. Through a further increase of the dark annealing temperature, the magnitude of this slow degradation is suppressed. This data provides essential information into the role that thermal history plays in the behavior of the still unidentified defect or defects, which is crucial for future studies of the degradation and methods to mitigate it.