Barrier technology providing exceptional stability of CIGS devices under accelerated damp heat conditions

Parallel to rapid prototype testing for moisture barrier performance, extensive failure mode analyses of inorganic direct cell coatings for CIGS solar cells have led to important conclusions regarding barrier degradation during exposure. Based on these analyses, a new strategy for direct cell barrier film technology has been developed that eliminates the primary root causes of failure. This approach provides exceptional damp heat stability to CIGS devices, even in the absence of additional encapsulation technology. Evaluation of time-to-failure data resulted in characteristic lifetime estimates of >1500 h at 85°C/85% RH for the new barrier film approach, compared to ~500 h for various silicon nitride based films under the same conditions. In fact, laboratory scale CIGS devices with the improved direct cell coating show >70% probability of surpassing 1000 h under damp heat stress and several cells have survived >3000 h under these conditions with less than 10% reduction in efficiency.