At this year’s fully online EU PVSEC, Michael Winter’s contribution on „Firing-Triggered LID (FT-LID) of the Carrier Lifetime in Cz-Si Wafers“ was awarded the EU PVSEC Poster Award.


So-called light-induced degradation effects are frequently observed in the majority of currently produced solar modules. These are due to a deterioration of the carrier lifetime (a measure of the quality of the material) in the silicon wafers used. Depending on whether the silicon used is monocrystalline (Czochralski Silicon or Cz-Si) or multicrystalline (mc-Si), the main degradation effect is either the activation of boron-oxygen (BO) defects or the so-called ‚Light and elevated Temperature Induced Degradation‘ (LeTID) effect. In addition, there have been several recent reports of LeTID-type effects on Cz-Si wafers and solar cells.

At the EU PVSEC Michael Winter presented his experimental approach to separate additional LeTID-type degradation effects in fired Cz-Si wafers from traditional BO defect activation. In the second part of his study, he compared the observed non-BO-related degradation effect in Cz-Si wafers with the standard LeTID effect typically observed in mc-Si material. He pointed out major differences that lead him to the conclusion that the detailed physics of the two degradation effects are not identical.

Watch Michael’s summary of his work here: