A novel non-destructive characterization method to investigate hot-spot formation in CIGS solar cells using lock-in thermography

This paper introduces a novel non-destructive characterization method to investigate reverse bias hot-spot formation in Cu(In,Ga)Se2 (CIGS) solar cell technologies based on lock-in thermography (LIT). CIGS solar cells technology is an innovative thin-film technology that is well known for its high efficiency. It is well known that partial shading can degrade module performance in CIGS and other thin-film technologies. Partial shading can lead to a reverse bias over cell which in turn leads to the formation of small hot-spots. Recent studies demonstrate that a positive feedback effect involving the high positive thermal coefficient of junction breakdown can play an important role in the formation of these hot spots. The LIT based method we present here allows the quantification of this positive feedback effect. This will allow a more detailed study of reverse bias hot-spot formation.