Rapid and Accurate Measurement of Ideality Factor and Parasitic Resistances of Thin Film Solar Cells

The sunshade method for the measurement of the ideality factor and resistances of solar cells is commonly used in silicon solar cells. However, the method is rarely employed for thin-film solar cells. In this paper, the sunshade method is applied to CIGS solar cells, and it is shown that the three major assumptions of the method remain valid for CIGS solar cells. The extracted parameters are compared to those calculated using other common methods, and the ideality factors and R s values are quickly determined and found to be nearly the same as those extracted through illuminated I–V fitting and dark I–V fitting.