Long-Term Degradation Analysis of Perovskite Solar Cells over Three Years

Power‐conversion efficiencies (PCEs) in perovskite solar cells (PSCs) have risen to levels that now rival established photovoltaic technologies. Yet translation to market hinges not on peak efficiency alone, but on rigorous demonstrations of operational and long-term stability. The literature remains fragmented: many stability studies are short in duration, poorly harmonized, and therefore difficult to compare or interpret. Because PSCs possess materials properties and degradation pathways distinct from conventional semiconductors, their durability may need to be assessed against adapted, technology-specific criteria rather than by direct analogy. Here we examine the influence of storage on PSC aging over a three-year horizon. Devices with the architecture glass/FTO/compact-TiO₂/mesoporous-TiO₂/perovskite/Spiro-OMeTAD/Au were fabricated and stored in nitrogen gloveboxes under inert atmosphere. Despite the ostensibly benign conditions, ToF-SIMS and XRD analyses reveal progressive layer disintegration that correlates with a decline in PCE from an initial ~17% to ~8% after three years. A salient feature of the aging process is the time-dependent diffusion of lead species toward the metallic back contact, which emerges as a dominant pathway for interfacial degradation. Complementary photoluminescence measurements show pronounced emission quenching in the perovskite layer, consistent with the formation of nonradiative recombination centers associated with ion migration. Taken together, these results underscore the need for stability protocols that capture PSC-specific failure modes, especially interfacial evolution and ion-driven defect formation, even under inert storage. By clarifying how materials transport and interface chemistry govern performance loss over multi-year timescales, this study provides actionable guidance for lifetime engineering and the reliable scale-up of PSC technology toward commercialization.