Stability of isotype reference cells used for multi-source solar simulator calibration

Calibration of individual zones in a multi-source solar simulator using isotype reference cells presents unique challenges. Higher bandgap materials are used as filter layers to match the spectral response of an active isotype cell to its corresponding response in a full multijunction cell. Experimental results suggest that luminescence from these filter layers could occur during calibration of isotype references, thereby artificially increasing the current output. We show that proton irradiation of the filter layers can quench radiative recombination within these layers thereby reducing the luminescent coupling. We also take a look at transient responses from some isotype cells.