QE(λ,VF) and I(VF) measurements on single and triple-junction a-Si:H solar cells

QE(λ, V_F) and I(V_F) were measured on a-Si:H single and triple-junction junctions with an integrated instrumentation system that has been previously reported by the author (1996). The goal of the investigations is to develop techniques for characterizing cells under power-generating conditions that may be useful in understanding cell operation and optimizing cell designs. The measurements suggest that photodegradation, and the associated defect states, play on important role in QE(λ, V_F) under dark and light bias conditions as V_F approaches the maximum power point