Validated Method for Repeatable Power Measurement of CIGS Modules Exhibiting Light-Induced Metastabilities

Michael Deceglie, Timothy Silverman, Keith Emery, William Marion, Sarah Kurtz, Daniela Dirnberger, Alexandra Schmid, Stephen Barkaszi, Nicholas Riedel, Larry Pratt, Samantha Doshi, Govindasamy Tamizhmani

Research output: Contribution to journalArticlepeer-review

7 Scopus Citations


We report on the validation of a stabilization procedure designed to minimize variations in repeated power measurements at standard test conditions caused by transient light-induced metastabilities in copper indium gallium diselenide (CIGS) modules. Such metastable effects frustrate the repeatable and accurate measurement of a module's performance in the electrical state to which it stabilizes under normal operation outdoors. The procedure studied here is based on a light exposure followed by forward electrical bias as the module cools to the measurement temperature. The procedure was tested in a lab-to-lab intercomparison involving five different labs. Results show that the procedure is effective in yielding repeatable measurements and that the variations due to metastabilities are of roughly the same magnitude as those associated with variations in illumination conditions between different flash simulators. We also find that temperature-corrected measurements made immediately upon completion of the light exposure are less repeatable than those made after the module has cooled to 25°C under bias.

Original languageAmerican English
Article number6994210
Pages (from-to)607-612
Number of pages6
JournalIEEE Journal of Photovoltaics
Issue number2
StatePublished - 2015

Bibliographical note

Publisher Copyright:
© 2011-2012 IEEE.

NREL Publication Number

  • NREL/JA-5J00-63237


  • Characterization
  • copper indium gallium diselenide (CIGS)
  • light soak
  • metastability
  • photovoltaic
  • transient


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