Mesoporous MOFs unlock concurrent gains in efficiency and stability of perovskite solar cells

Metal-organic frameworks (MOFs) materials have emerged as promising additives to enhance the crystallinity and durability of lead halide perovskite solar cells (PSCs). However, conventional MOFs provide limited infiltration of perovskite precursors and exhibit weak interfacial interactions, restricting their functional contributions. Here, we integrate a hierarchically mesoporous UiO-66(Ce) MOF into the perovskite active layer, which features enlarged pore sizes (around 10 nm) and abundant carboxylate (–COO − ) groups. This design promotes perovskite precursor diffusion and creates structured interfaces for crystallization, allowing for strong Pb 2+ coordination and guided crystal growth. Consequently, perovskite films demonstrate reduced trap density and improved charge transport. The resulting PSCs achieve an efficiency of 20.62 %, outperforming the pristine control (18.86 %). Notably, the devices show superior long-term stability, retaining 99 % of their initial efficiency after 30 days under ambient conditions, 82 % after 15 days at 60 °C in nitrogen, and stable output under continuous illumination. In addition, the mesoporous UiO-66 interlayer mitigates Pb 2+ leakage upon water exposure. These results highlight mesoporous MOFs as multifunctional additives for enhancing the efficiency, durability, and environmental safety of perovskite photovoltaics. • A hierarchically mesoporous UiO-66(Ce) MOF with ~10 nm pores was synthesized to enhance perovskite film quality. • Strong Pb 2+ –COO - coordination facilitates in situ crystallization and reduces trap density. • Modified PSCs achieved a higher power conversion efficiency than control device with reduced hysteresis and enhanced charge transport. • Devices maintained 99% efficiency after 30 days in ambient air and 82% after 15 days at 60 °C. • The mesoporous MOF layer significantly suppresses Pb 2+ leakage upon water exposure.