Staebler-Wronski Effect

Amorphous silicon-based solar cells exhibit a significant decline in their efficiency during their first few hundred hours of illumination; however, the degradation of multiple layer solar cells and of nanocrystalline silicon cells is much lower. The

single-junction cell loses about 30 % of its initial efficiency after about 1000 hours; the triple-junction module loses about 15 % of its initial efficiency (see Fig. 41.2).

All amorphous silicon-based solar cells exhibit such degradation with light, which is called the Staebler-Wronski effect (Staebler and Wronski 1977a, 1977b). The effect anneals out nearly completely within a few minutes at temperatures of about 160 0 C, and anneals substantially in outdoor deployment at summer operat­ing temperatures of 60 0 C.

The Staebler-Wronski effect contributes to noticeable seasonal variations in the conversion efficiency of a-Si:H as observed for modules in the field in Switzerland (since during the winter season the daytime temperature was insufficient for anneal­ing), but there was no discernible, permanent degradation of this module over the three-year extent of this test; one study over ten years does suggest degradation of about 0.7 % per year (Gregg et al. 2005), which is comparable to the long-term degradation of c-Si cells.

Updated: August 24, 2015 — 4:02 pm