Regulated Crystallization Through Intermolecular Interactions Bridging for Efficient Tin‐Based Perovskite Solar Cells

Abstract Tin halide perovskite (THP) has emerged as a promising lead‐free material for high‐performance solar cells, attracting significant attention for their potential use for energy conversion. However, the rapid crystallization of THP due to its high Lewis acidity and easy oxidation of Sn 2+ leads to poor morphology and rampant defects in the resulting perovskite films. These strongly hamper the advances in efficiency and stability in THP solar cells. Herein, a comprehensive crystallization regulation strategy is demonstrated by introducing methyl carbazate (C 2 H 6 N 2 O 2 , MeC) to regulate the crystallization kinetics of perovskite through inter‐molecular interactions. The coordination bonds (O…Sn) and hydrogen bonds (N─H…O) between MeC and perovskite bridge the perovskite lattice together, helping suppress the oxidation of Sn 2+ , meanwhile, restraining the fast crystallization of perovskite in the precursor solution, by enhancing nucleation sites. More importantly, the connection by MeC can reduce the deep‐level trap state defect density, significantly restraining non‐radiative recombination and improving the carrier lifetime. Consequently, this facile strategy offers valuable insights into THP crystallization kinetics and allows an enhanced high power conversion efficiency from 10.43% to 14.02% to be achieved with good stability.