Performance Mapping of Multijunction Solar Cells Based on Electroluminescence

Electroluminescence intensity maps of all three subcells of space grade III-V multijunction cells were obtained with the help of dedicated imaging sensors at a range of different injection currents. Solely based on these data, making use of the homogeneity of one subcell, the local diode properties of an equivalent single junction cell were obtained and converted into spatial distributions of open circuit voltage (V _oc) and current at a fixed operating voltage (I _op). On a sample basis of more than 200 cells, V _oc and I _op characterizing the entire cell were determined with an accuracy of plusmn3 mV and plusmn5 mA, respectively.