Micelle‐Induced Nucleation and Surface Chemical Polishing Co‐Strategy for Efficient Tin‐Lead Mixed Perovskite Solar Cells

Tin-lead mixed perovskite (TLP) solar cells, due to their tunable bandgap, have emerged as one of the most promising candidates for approaching the Shockley-Queisser limit. However, the strong Lewis acidity of the tin-halide component in TLP increases the propensity for defect formation and phase separation during the fabrication process. In this study, a bimolecular synergistic regulation approach that combines micelle-induced nucleation and surface chemical polishing for crystallization control and defect passivation in TLP solar cells is introduced. The TLP precursor micelle-induced nucleation strategy modifies the characteristic of the micelles through hydrogen-bonding and selective coordination with 4-hydrazinylbenzonitrile hydrochloride (HBN), thereby lowering the critical nucleation concentration and accelerating the uniform and simultaneous nucleation of the perovskite. This crystallization control strategy significantly enhances the quality of TLP films and suppresses defect introduction during the uncontrollable film formation process. The surface chemical polishing strategy entails the passivation of TLP interface defects with hydrazine-based phenylsulfonamide hydrochloride (HSA), inhibiting the oxidation of divalent tin and optimizing charge carrier extraction at the interface. Ultimately, a TLP solar cell with a power conversion efficiency of 24.01% is achieved, and the encapsulated device exhibits an T80 value of 391 h under prolonged illumination.