Analysis of Light-Induced Degradation in Amorphous Silicon Alloy Solar Cells and Its Application to Accelerated Test Method

Light-induced degradation in amorphous silicon alloy single-junction solar cells has been studied systematically. The dependence of the light-induced degradation in the conversion efficiency and the other photovoltaic parameters on light intensity and bias voltage has been clarified quantitatively. It has been shown that the light-induced degradation characteristics of the photovoltaic parameters can be described by a single function of certain normalized parameters of the exposure condition. Theoretical background for the experimental results has been clarified by applying a defect creation model modified to the a-Si alloy solar cells. Moreover, using the above single function, we have proposed a new accelerated test method by indoor measurement under the solar simulator instead of outdoor testing under natural sunlight. The validity of the accelerated test method has been confirmed experimentally.