Crystalline silicon short-circuit current degradation study: initial results

Following our observation of slow degradation of short-circuit current (I_sc) in crystalline silicon (x-Si) modules that was correlated with ultraviolet (UV) exposure dose, we initiated a new study of individual x-Si cells designed to determine the degradation cause. In this paper, we report the initial results of this study, which has accumulated 1056 MJ/m² of UV dose from 1-sun metal-halide irradiance, equivalent to 3.8 years at our test site. At this time, the control samples are unchanged, the unencapsulated samples have lost about 2% of I_sc, and the samples encapsulated in module-style packages have declined from 1% to 3%, depending on cell technology.