Room temperature recovery of light induced degradation in a-SI:H solar cells

In this paper, high intensity light-soaking and post-degradation room temperature recovery of single junction a-Si:H solar cells are investigated. After high intensity short term light-soaking, it was found that the degraded state was itself not stable. In the dark, fast degraded samples improved with time, even at room temperature. Two different sets of samples showed recovery rates in the range of 1% gain of relative efficiency per hour. Recovery kinetics were the same in the dark and under low intensity carrier generation. Continued high intensity light soaking resulted in a steady decrease of the recovery rate with time. To explain this behavior, the authors suggest the presence of a non-electronic, slow process related to lattice reconfigurations that lock-in the light-induced defect states