Carrier lifetime model for the optical degradation of amorphous silicon solar cells

Abstract
The light-induced performance degradation of amorphous silicon solar cells is described well by a model in which the carrier lifetimes are determined by the dangling bond density. Degradation will be slower in solar cells operating at lower excess carrier concentrations. This is documented with a comparison of degradation data for cells at open circuit versus load, and for single versus cascade cells. At sufficiently long times, the efficiency will decrease at approximately the same rate for all cases, with an offset in time between the individual cases which can be calculated.