Mobile Oxygen Capture Enhances Photothermal Stability of Perovskite Solar Cells Under ISOS Protocols

Stability testing protocols from the International Summit on Organic and Hybrid Solar Cell Stability (ISOS) are essential for standardizing studies on the photothermally operational stability of perovskite solar cells (PSCs). Under photothermal conditions, the migration of oxygen from SnO₂ layer induces cationic dehydrogenation at the A-site of the perovskite, accelerating degradation to PbI₂. This leads to the formation of photoinduced I₂ and Pb⁰ defects, significantly compromising long-term stability. In this study, ordonezite (ZnSb₂O_6-x) as a multifunctional electron transport layer (ETL) that captures migrating oxygen atoms at the SnO₂/perovskite interface is introduced, effectively preventing degradation of the buried interface. Additionally, the lattice match between ZnSb₂O_6-x and perovskite facilitates well-ordered perovskite film growth. As a result, PSCs featuring ZnSb₂O_6-x ETLs achieved a high power conversion efficiency of 25.02% and retained 90.62% of their initial performance after 1000 h under the ISOS-D-2 protocol. Furthermore, devices demonstrated remarkable thermal stability, maintaining 83.69% of their original performance after 800 h of maximum power point tracking at 85 °C, meeting the stringent ISOS-L-2 protocol requirements.