Metal–organic-framework-assisted inhibition of interface oxygen migration for exceptional thermal stability of perovskite solar cells

Formamidinium (FA)-based perovskite solar cells (PSCs) have emerged as one of the most promising candidates for next-generation photovoltaics due to their exceptional power conversion efficiency (PCE). However, their commercial deployment is hindered by poor stability, particularly under strict environmental stresses like high temperature, with interface degradation and ion migration being key challenges. In this work, we introduce metal-organic framework (MOF) materials composed of assembled Zr clusters and functional amino/sulfhydryl groups at the SnO₂/perovskite interface within the n-i-p structure to address these issues. The incorporation of MOFs—specifically their robust framework with confined spatial structure and functional groups—plays a pivotal role in hindering oxygen migration from SnO₂ to perovskite, leading to enhanced thermal stability of both perovskite films and PSCs. Furthermore, the anchoring of MOF on SnO₂ and perovskite is essential for passivating interface defects, promoting perovskite crystallization, and reducing carrier recombination, all of which contribute to enhanced charge transport. As a result, the MOF-modified devices achieve a champion PCE of 25.22%, with the MOF-modified devices retaining 100% of their initial PCE after 2000 hours of thermal aging at 85 °C in N₂. This study highlights the structural integrity and functionality of MOFs for achieving high-performance and long-term stable PSCs.