IN-SITU FORMATION OF HUMIDITY-SENSITIVE DEVICES FOR THE EVALUATION OFSOLAR PANEL ENCAPSULATIONS

A certain deterioration of solar panels under long-term working condit ions can be attributed to the effect of humidity entrapment or penetra tion in the encapsulate polymer. Afterwards, corrosion of contacts can be initiated, with device failure as a consequence. A measuring techn ique that allows the monitoring of humidity changes inside the finishe d solar panel is described. The electrical characteristics of the enca psulating polymer are monitored by electrochemical impedance spectrosc opy, using screen-printed interdigitated electrodes as electrical cont acts. The alumina substrate containing the sensing structure is encaps ulated under circumstances identical to those used for the solar cells , and the humidity-related electrical characteristics of the encapsula ting polymer itself are used as the sensor signal. The in fluence of t he construction of multilayer structures with different protective top layers (glass, Tedlar(R)) on humidity is reported.