High reliability three-stacked amorphous-silicon solar cell

The light-induced degradation in a-SiC, a-Si, and a-SiGe single cells was investigated under various illumination conditions. It was found that the degradation characteristics of μτ products in the single cells can be described simply by a function of the photogenerated current and the recombination current. The light-induced degradation in stacked cells was also investigated by evaluating the individual current-voltage characteristics. It was also found that degradation characteristics in component cells of stacked cells show good agreement with the characteristics predicted from the μτ product in single cells. By designing a high-reliability stacked cell using these results, an a-Si/a-Si/a-SiGe three-stacked solar cell was obtained with an initial conversion efficiency of 10.0% and a degradation ratio of 10% after a light exposure equivalent to a one-year field test