Process Dependent Instabilities In Cu(In,Ga)Se2 Solar Cells Under Water Ingress

CIGS solar cell degradation due to the impact of moisture and heat treatment was studied as a function of sputtering pressure of the transparent conductive oxide (TCO) deposition. The devices were immersed in deionized water for up to 72 hours. The results were compared and showed decrease in efficiency with time. The performance loss was mainly driven by change in shunt resistance, impacting the FF. Decrease in current density and increase in series resistance were also noted. Interestingly, performance loss was found to be more drastic for the devices with TCO deposited at higher pressure than at lower pressure.