Published online by Cambridge University Press: 25 February 2011
Amorphous silicon (a-Si) based solar cells with a double-stacked tandem structure have been studied with a view to reduce light-induced degradation in photovoltaic performance without lowering the initial conversion efficiency. We have attained a conversion efficiency of 11.3% in a 1cm2 a-Si/a-Si tandem cell and 10.8% in a 1cm2 a-SiC/a-Si tandem cell. Using an a-Si/a-Si tandem cell with an initial efficiency of more than 10%, we have carried out a light soaking test, and found that the degradation in conversion efficiency was about 10% under open-circuit condition after 600 hours exposure.