Output evaluation of a world’s highest efficiency flat sub module with InGaP/GaAs/InGaAs inverted triple-junction solar cell under outdoor operation

We discussed the outdoor operation of a fixed flat sub module with an InGaP/GaAs/InGaAs inverted metamorphic triple-junction solar cell (IMM module) for the first time in the world. The global solar spectrum distribution was assessed using the average photon energy (APE) and spectral matching ratio (SMR) indexes in this study. The conversion efficiency of the IMM module was more than 30% and was markedly affected by APE rather than by module temperature under real environmental conditions. SMRBottomTop markedly increased in the high APE region. In the case of APE of more than 1.60 eV, the photocurrent of the bottom subcell decreased owing to the blue-rich spectrum, which limited the short-circuit current. The absorption region of the bottom subcell overlapped with the water absorption region in the solar spectrum; therefore, environmental conditions such as water precipitation greatly affected the output of the current-matching inverted triple-junction solar cell.