Direct ALD of amorphous MoS2 thin films for extra-terrestrial photovoltaic applications

Abstract

The design of solar cells for space applications demands a high power-to-weight ratio and resilience against extreme environments, including proton radiation and rapid temperature fluctuations. However, existing technologies come with drawbacks: III-V materials are expensive, CdTe and CIGS rely on scarce and toxic elements, perovskites suffer from stability issues, and silicon has limited limited tolerance to space-stressors. This study investigates ultra-thin amorphous MoS2 as a viable alternative, offering a balance of affordability, environmental sustainability, and robustness. Using atomic layer deposition (ALD), we enable scalable production of photovoltaic-grade amorphous MoS2 thin films, achieving large-area coatings with exceptional uniformity, smoothness, and precise thickness control. Passivation increases the charge carrier lifetime to approximately 100 ns, highlighting the potential for high specific power in a fully encapsulated module. Additionally, unpassivated films show minimal disorder when exposed to high-energy, high-fluence proton radiation. These results highlight the promise of amorphous MoS2 for space-based photovoltaics and lay the groundwork for further studies on its long-term durability in extraterrestrial conditions.