A study on the radiation effects on flexible GaInP/GaAs/InGaAs triple-junction solar cells using photoluminescence measurements

Abstract Herein, the photoluminescence (PL) measurements were used to study and investigate the degradation behavior of flexible GaInP/GaAs/InGaAs inverted metamorphic triple-junction (IMM3J) photovoltaics (PV) under 1 MeV electron irradiation. The changes in PL intensity with varying electron irradiation fluence enabled the acquisition of effective minority carrier lifetimes ( τ eff ) for top GaInP, middle GaAs, and bottom InGaAs subcells under different irradiation conditions. Comparing the changes of τ eff before and after the electron irradiation, it was found that the τ eff of the InGaAs bottom subcell deteriorates most severely with increasing electron irradiation fluence. Based on the degradation behaviour of the solar cell output characteristics, it was confirmed that the overall performance degradation of the flexible GaInP/GaAs/InGaAs IMM3J solar cell is mainly due to the degradation of the current density of the InGaAs bottom subcell.