Indoor characterisation of thin-film PV modules installed for 4.6 years in desert conditions

Degradation of commercially available CdTe and CIGS PV modules installed in the desert conditions, are not well understood, because they have been in operation for relatively short period compared to crystalline silicon PV technology. In this paper, we investigate the degradation rate of both these thin-film technologies using indoor characterization methods. The calculated annual degradation rate of CdTe technology (1.3-2.2 percent/year) is lower than CIGS (5.3-8.8 /year). The main cause of this degradation is the reduction in fill factor caused by formation of permanent shunts. These shunts were characterized using Electroluminescence and microscopic imaging.