Metallic Lead to Perfect Perovskite: A Bottom-Up Vapor-Assisted Colloidal Strategy for High-Performance Solar Cells

Using elemental lead (Pb 0 ) as a precursor offers an upstream and atom-economical alternative route for perovskite synthesis. However, producing perovskite solar cells (PSCs) from Pb 0 remains fundamentally challenging because Pb 0 is hard to convert to Pb 2+ via ordinary approaches, while any remaining Pb 0 acts as deep-level defects in perovskite. To address this challenge, Pb 0 first reacts with I 2 in N, N -dimethylformamide and dimethyl sulfoxide, yielding well-dispersed PbI 2 colloidal precursors that facilitate subsequent full conversion to perovskites through vapor–solid reaction with formamidinium iodide vapors. Devices starting from Pb 0 perform much better than those from as-purchased PbI 2, in both efficiency and stability, achieving vapor-assisted solution-processed 22.65% efficiency under simulated AM1.5G illumination (over 20.65% from PbI 2 ). These findings suggest that high-quality perovskites may also be prepared from PbI 2 alternatives, even its upstream material Pb.