Corrosion under Front Electrodes of Crystalline Silicon Photovoltaic Cells Predominantly Contributes to Their Performance Degradation

To address the origin of the elevated series-resistance (R
_s
), which is a primary cause of corrosive degradation observed in field-aged photovoltaic (PV) modules, we evaluated the electrical characteristics of PV cells corroded with acetic acid vapor. The increase in R
_s
was detected at the interface between the front electrodes and the associated silicon wafer, where is identical to the location of a novel impedance emerging by the corrosion. These results suggest that the corrosive degradation is virtually governed by the evolution of electrical characteristics in front surface, but not that in rear surface of PV cells.