Probing the degradation pathways in perovskite solar cells

Perovskite solar cells (PSCs) have almost climbed up with established photovoltaic technologies in terms of power conversion efficiency. Hence, it is crucial to understand the operational as well as long-term stability for commercialization. However, stability studies are often conducted in non-standardized and short-term ways, resulting in data that cannot be understood effectively. Additionally, assessing the stability of perovskite solar cells, which have unique properties, may require adjusting common standards. Our research investigates the storage affects the aging of perovskite solar cells for a long period span of 3 years. Glass/FTO/compact-TiO₂/mesoporous-TiO₂/perovskite/Spiro-OMeTAD/Au structured solar cell devices are fabricated and tested for stability. The power conversion efficiency (PCE) drops significantly from 17 % to 8 % over three years of the stored perovskite solar cells in N₂ filled glove box, mainly due to the decomposition of the perovskite layer as confirmed by ToF-SIMS and XRD studies. Interestingly, lead (Pb) diffusion towards metallic contact becomes a dominating factor over time. Photoluminescence studies also confirm strong quenching of the perovskite layers emission spectra due to the defects through ion migration process. Our findings offer a pathway to understanding the longevity of PSCs and additionally provide an opportunity to manufacture large-scale PSCs with the aim of commercialization.