1 MeV electron irradiation effect and damage mechanism analysis of flexible GaInP/GaAs/InGaAs solar cells.

In this study, the degradation behavior of flexible GaInP/GaAs/InGaAs (IMM3J) solar cells and their metamorphic subcells under 1 MeV electron irradiation was investigated. The remaining factors such as short-circuit current density (Jsc), open-circuit voltage (Voc), and maximum power (Pmax) were 95.62, 85.52, and 79.73%, respectively, at an irradiation fluence of 2 × 10¹⁵ e/cm². The spectral responses of the InGaAs and GaAs subcells degraded significantly, and the InGaAs subcell experienced greater degradation than the GaAs subcell after irradiation. In addition, the current-limiting unit was switched from GaInP to InGaAs after irradiation. Defect analysis by deep-level transient spectroscopy (DLTS) revealed that with increasing irradiation fluence, the defects that had the greatest impact on the performance of GaAs subcells were E_V + 0.36 and E_V + 0.42 eV. For InGaAs subcells, the defects that had the greatest impact on the performance were E_V + 0.29 and E_V + 0.24 eV. The decrease in the minority carrier lifetime is the main reason for the decrease in the electrical performance of solar cells, and the variation in the effective minority carrier lifetime (τ_eff) in the subcells with the irradiation fluence was calculated based on the DLTS results. At a fluence of 2 × 10¹⁵ e/cm², the τ_eff of the GaAs and InGaAs subcells decreased from 2.93 × 10⁻¹⁰ and 9.10 × 10⁻¹⁰ s to 1.56 × 10⁻¹¹ and 1.60 × 10⁻¹² s, respectively. These results provide a reference for predicting the degradation of short-circuit current and open-circuit voltage of flexible IMM3J. [ABSTRACT FROM AUTHOR]