A Silver Lining for Space Solar Cells: Ag‐Enhanced CIGS Solar Cells Resist and Recover From Radiation

Cu(In, Ga)Se 2 (CIGS) solar cells are known for their remarkable radiation tolerance, making them promising candidates for space applications. While silver (Ag) incorporation has been reported to enhance absorber quality, its role in radiation‐induced defect formation and recovery dynamics remains insufficiently explored. In this study, a comparative investigation was conducted using CIGS absorber layers with and without Ag incorporation. Both types of devices were subjected to proton irradiation to simulate space radiation conditions, followed by heat‐light soaking (HLS) treatments to assess defect recovery and device stability. The results reveal that Ag incorporation effectively suppresses the formation of selenium vacancies ( V Se ) and the associated V Se – V Cu defect complexes. After HLS, defect states shift from deep levels to shallower ones or below detection, with significant recovery in carrier lifetime and radiative intensity. Thermal energy heals displacement damage, while light promotes charge‐state transitions of V Se – V Cu , leading to increased carrier concentration. Enhanced thermal conductivity and photoresponse in Ag‐incorporated samples further amplify recovery, enabling irradiated devices to retain up to 139% of their initial efficiency. These findings reveal a silver lining for space solar cells: Ag not only resists radiation damage but actively facilitates healing.