Induced degradation on c-Si solar cells for concentration terrestrial applications

There are several factors that can affect the reliability of concentration solar cells and influence the final devices performances. Electrical characterizations like the dark I-V curve in reverse and forward bias, the I-V curve under illumination and the quantum efficiency are generally used to test the stability of the cells. For this reason also in the packaging processes, used for making external connections, great attention is devoted to guarantee maximum reliability versus thermally induced expansions, contractions and/or stresses which might cause a degradation of the device performance. After the observation of the effects due to the packaging process of ENEA c-Si concentration solar cells, we analyze the attitude of the completely "packed" device to dissipate heat as compared to a commercial c-Si back contact concentration solar cell. Then we propose accelerated degradation tests to study, through electrical characterizations, the reliability of ENEA solar cell against high light intensities and umidity. In particular, for both ENEA and commercial devices the effects of each considered degradation mechanism on final behavior will be reported.