CIGS PV reliability - Current practices, challenges and approaches

The long term sustainable output power production from any photovoltaic array (PV) array depends on the climate (temperature and humidity) in which PV modules are deployed. The degradation of CIGS PV modules outdoors is complicated by various packaging methods (flexible or rigid), interconnect options (cell to cell interconnects or monolithic integration), the different manufacturing methods used to fabricate films in the CIGS stack and the corresponding material and interfacial properties of the semiconductor layers. There is a need to address the challenges in designing indoor accelerated tests with appropriate stress conditions to replicate the observed failure mode and in identifying the failure mechanisms responsible for the failure. This review paper gives an outline of the current practices, challenges and approaches in identifying the stress factors and degradation mechanisms responsible for the device failure by designing appropriate combinatorial stress tests and test structures for indoor accelerated stress tests and relating the results to outdoor module reliability.