Fast Regeneration Processes to Avoid Light-Induced Degradation in Multicrystalline Silicon Solar Cells

Abstract

Light-induced degradation (LID) of multicrystalline silicon (mc-Si) solar cell performance has been reported to be surprisingly strong for conditions relevant under field operation. In paticular, solar cells with dielectrically passivated rear sides such as passivated emitter and rear cells are affected by this LID effect that can cause a loss of more than 10% <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rel</sub> in cell efficiency. With the root cause for the observed degradation being unknown to date, the underlying defect, however, has also been reported to be permanently deactivated under the same conditions at even longer time scales. However, a severe power loss due to the mc-Si specific LID is observed before the cells recover due to the long time scales of the regeneration under these conditions. Hence, regeneration on short time scales similar to the fast regeneration processes being reported for the boron–oxygen defect within p-type Czochralski-grown silicon is highly desirable also for p-type mc-Si, especially since mc-Si currently dominates industrial solar cell production. Within this work, partial regeneration of the defect causing the mc-Si specific LID is shown to be possible within less than 30 s, reducing the impact of LID by up to 60%, which leads to a significantly increased performance of the regenerated mc-Si solar cells.