Subcell Characterization in Multijunction Solar Cells Using Pulsed Light

The photocurrent versus open-circuit voltage characteristic of individual subcells in a multijunction solar cell can be measured by illuminating the subcell with a pulse sequence of spatially homogeneous laser light. In this paper, we demonstrate the applicability of this method for four junction solar cells. Furthermore, the degradation of triple junction solar cells after electron irradiation is analyzed on the subcell level. Subcell performance parameters are derived, and results are compared with electroluminescence-based results. The influence of luminescent coupling and semitransparency effects to lower subcells are quantified by simulations.