The stability of multi-junction a-Si solar cells

Experimental results on the stability of multijunction cells are presented. It is demonstrated that multijunction cells are more stable than single-junction cells and that the stability improves as the number of junctions increases. It is further shown that the rate of degradation of multijunction devices can be explained in terms of the rates of degradation of their individual i layers. It is thus possible to predict the amount of photodegeneration of multijunction devices after prolonged light soaking, knowing the rates of degradation of single-junction cells in terms of the i-layer thicknesses and the intensity of the illumination to which they are exposed.