Researchers from the University of Potsdam, HZB, Humboldt University of Berlin and The Chinese University of Hong Kong recently took a step toward understanding and improving the stability of perovskite solar cells. Despite their impressive efficiencies, lead-based perovskite solar cells still struggle with long-term instability and the inherent toxicity of lead. These issues stem largely from mobile halide ions within the perovskite structure, which migrate under operational conditions, leading to device degradation.
To tackle this challenge, the team investigated ion migration in four representative perovskite compositions: pure lead-based, mixed lead–tin, and two tin-based perovskites synthesized using different solvents (DMSO and DMF–DMI). Their detailed quantitative measurements revealed striking differences in ion density and mobility across these materials. The lead-based perovskites exhibited the highest ion densities, while incorporation of tin reduced these values slightly. Tin-based perovskites processed with DMSO showed further improvement, but the real breakthrough came from those prepared using the DMF–DMI solvent, which displayed an ion density almost ten times lower than in the lead-based counterparts.
Even more promising, the DMSO-free tin perovskites maintained device stability over extended operation, reaching T80 ≈ 600 hours with minimal ionic losses. The results confirm that tin-based materials not only offer an environmentally friendly alternative but also exhibit intrinsically slower degradation and smaller ion-induced instabilities. By suppressing ion migration, these materials overcome one of the biggest barriers to perovskite commercialization.
This work highlights the potential of tin-based perovskites and underscores the importance of solvent engineering in their fabrication. As the researchers note, continued optimization of processing methods and defect passivation could further reduce ion densities and unlock even greater performance. The study provides a clear path forward for developing stable, non-toxic, and high-efficiency thin-film solar cells - bringing perovskite photovoltaics one step closer to sustainable, commercial viability.
