Subcell I-V characteristic analysis of GaInP/GaInAs/Ge solar cells using electroluminescence measurements

The I-V characteristics of the individual subcells of a monolithic Ga 0.50 In0.50 P/ Ga0.99 In0.01 As/Ge triple-junction solar cell have been extracted from measurements of the electroluminescence peak intensity as a function of the electroluminescence injection current. By using the spectral reciprocity relation between the electroluminescence and the quantum efficiency, the individual subcell I-V characteristics were derived. It is shown that the subcell dark I-V characteristics and the subcell illuminated I-V characteristics are accessible under variable spectral illumination conditions.