Corrosion of the transparent TCO (Transparent Conductive Oxide) layer is its opacity and applies to thin-film cells [1], as well as those produced from amorphous silicon [2]. The TCO corrosion occurs in the presence of leakage currents that generate a voltage between the cell and the ground, which causes sodium atoms, a component of glass, to enter the TCO layer. The corrosion progression starts at the edges of the photovoltaic module, then the process progresses to further areas of the cell. As a consequence, the layer becomes cloudy and the cell efficiency decreases.
Depending on the position of the TCO layer in the cell, we distinguish between substrate technologies, when the layer is directly adjacent to the glass layer of the cell, and superstrate technologies, when the TCO layer is separated from the glass by a luminate layer. For this reason, cells manufactured using substrate technology are most vulnerable. In order to prevent corrosion of the TCO layer, it is recommended to use transformer inverters (galvanic isolation) and to ground the pole „-” of the module table.