Can the Staebler-Wronski Effect Account for the Long-Term Performance of a-Si PV Arrays?

We suggest a model for the Staebler-Wronski degradation of a-Si-based solar cells that can account for long-term performance observations of deployed a-Si photovoltaic modules. The model suggets that the stabilization of the Staebler-Wronski degradation does not occur because an equilibrium between light-induced degradation and thermal or light-induced recovery is reached. Rather, stabilizationoccurs because the degradation phenomenon itself is self-limiting, i.e., once enough degradation has been introduced, the degradation process diminishes. This model shows that the module performance and the long-term power output of an a-Si PV array depend not only on the operating conditions, but also, on the temperature history of light exposure. This makes it difficult to accurately predictthe exact amount of degradation in the field.