Influence of light irradiation on the charge-accumulation-type potential-induced degradation of n-type front-emitter crystalline Si photovoltaic modules

Abstract We investigated the influence of light irradiation on the charge-accumulation-type potential-induced degradation (PID) of n-type front-emitter (n-FE) crystalline silicon (c-Si) photovoltaic (PV) modules. A PID test under one-sun irradiation leads to faster reductions of short-circuit current–density ( J sc ) and open-circuit voltage ( V oc ) compared to the case of a PID test in the dark. This indicates that light irradiation accelerates the charge-accumulation-type PID of the n-FE PV modules. The J sc and V oc reductions become slower under irradiation without ultraviolet (UV) light, showing almost the same time dependence as the PID test in the dark. The acceleration of PID by the addition of UV light may be explained by the excitation of electrons at K 0 centers in silicon nitride (SiN x ) and their faster drift to the surface by the electric field applied to SiN x .