Recent advancements have substantially enhanced the power conversion efficiency (PCE) of organic solar cells (OSCs), with reported values now exceeding 20%. Among these developments, OSCs fabricated on flexible plastic substrates have garnered significant interest owing to their notable benefits, including compatibility with roll-to-roll mass production, reduced weight, superior mechanical flexibility, and scalability [2]. Additionally, OSCs exhibit exceptional specific power (up to 40 W g⁻¹) alongside robust mechanical properties, rendering them highly promising for space applications. Consequently, a critical factor determining their viability for such use is their stability when exposed to cosmic radiation.

Herein, we present a systematic investigation of the stability of OSCs based on PM6:L8-BO donor-acceptor system under simulated space environment stressors, including ionizing radiation, extreme thermal cycling, and prolonged ultraviolet (UV) exposure. Our results demonstrate that these OSCs have a promising potential, sustaining high performance even at substantial radiation doses. Specifically, they retain their efficiency after exposure to 15 kGy of γ-radiation. High-energy electron irradiation (8.5–10 MeV) with a fluence of 10¹⁴ e/cm² caused a ~30% reduction in the device’s power conversion efficiency (PCE) compared to its initial value. Comparable degradation effects were observed after proton irradiation (18 MeV, fluence of 10¹³ p/cm²). Notably, these radiation doses correspond to levels accumulated over decades in low Earth orbit (LEO, e.g., the International Space Station’s orbit). When exposed to accelerated neutron flux (2 MeV, U-235 source, fluence up to 10¹⁴ n/cm²), OSCs demonstrated exceptional stability with no significant PCE loss. The cells also endured 500 hours of hard UV-light exposure, retaining up to 40% of their initial PCE. Additionally, the study evaluates OSCs’ resilience to white-light exposure. A series of experiments revealed their stability under extreme temperature fluctuations (+80°C to –85°C), withstanding at least 600 thermal cycles.

These results demonstrate the strong potential of OSCs as an emerging photovoltaic technology for space applications. Moreover, our findings reveal promising opportunities for developing next-generation organic semiconductor materials that could substantially improve OSCs performance and operational viability in real-world space environments.