LETID in Legacy and Modern PV Modules: Accelerated Testing and Field Deployment

Joseph Karas, Ingrid Repins

Research output: NRELPoster


The kinetics of light- and elevated temperature-induced degradation (LETID) in silicon solar cells depend on the precise operating excess carrier density (?n) of the device. This dependency causes differences in the way LETID manifests in modern, higher-efficiency devices compared to lower-efficiency, legacy devices that might have been deployed in the field in previous years. In this work we model how different vintages of devices are expected to behave in both accelerated laboratory testing, as well as field deployment. The differing excess carrier densities encountered in various module vintages has implications both for interpreting accelerated test data, as well as identifying, diagnosing, and potentially treating LETID in the field.
Original languageAmerican English
StatePublished - 2022

Publication series

NamePresented at the 49th IEEE Photovoltaic Specialists Conference (PVSC 49), 5-10 June 2022, Philadelphia, Pennsylvania

NREL Publication Number

  • NREL/PO-5K00-83052


  • excess carrier density
  • light and elevated temperature induced degradation
  • PV modules


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