Redirecting wet-interfacial redox pathways for efficient inverted perovskite solar cells

Carbazole-based phosphonic acid self-assembled monolayers (SAMs) are essential for high-efficiency p-i-n perovskite solar cells. However, during processing, these SAMs inevitably contact perovskite inks, where their acidity triggers a dimethyl sulfoxide (DMSO)-mediated iodide redox reaction that imprints device performance, representing a universal bottleneck for inverted devices. We resolve this SAM-triggered redox mechanism and introduce chemistry-matched hydrazide additives to mitigate the degradation. These additives abrogate DMSO activation and redirect unwanted by-products toward benign hydrazide-formamidinium adducts. Consequently, we achieved power conversion efficiencies (PCEs) of 27.7% (certified 27.4%) in small-area (0.06 cm²) cells and 20.1% in 2.0 m² modules, along with T95 lifetimes of ~2000 hours of maximum power point tracking (MPPT) at 85°C and ~1500 hours MPPT at 85°C and 85% relative humidity.