On the Accuracy of Spectral Adjustment for Performance Measurements of Multijunction Solar Cells

Accurate measurement of the performance of multijunction solar cells under Standard Test Conditions (STC) requires adjustment of the spectral output of the solar simulator to achieve a spectral irradiance matching condition under which the current in each junction under the solar simulator is the same as the current that the particular junction would carry under the reference spectrum. To quantify if this condition has been achieved, a "current balance" is calculated for each junction, typically labeled Zi for the i-th junction and it is generally accepted that 0.99