Controllable Iodoplumbate-Coordination\nof Hybrid Lead\nIodide Perovskites via Additive Engineering for High-Performance Solar\nCells

The crystallization and growth of perovskite crystals\nare two crucial\nfactors influencing the performance of perovskite solar cells (PSCs).\nMoreover, iodoplumbate complexes such as PbI<sub>2</sub>, PbI<sub>3</sub><sup>–</sup>, and PbI<sub>4</sub><sup>2–</sup> in perovskite precursor solution dictate both the quality of perovskite\ncrystals and the optoelectrical performance of PSCs. Here, we propose\nan iodoplumbate-coordination strategy that employs pentafluorophenylsulfonyl\nchloride (PTFC) as an additive to tailor the crystal quality. This\nstrategy directly affects the thermodynamics and kinetics of perovskite\ncrystal formation by regulating hydrogen bonds or coordination bonds\nwith Pb<sup>2+</sup> or I<sup>–</sup> ions. Subsequently, the\nsynergistic effect of the PTFC and FA<sup>+</sup> complex was beneficial\nfor intermediate-to-perovskite phase transition, improving the crystalline\nquality and reducing the defect density in the perovskite film to\nsuppress nonradiative recombination loss. Consequently, the treated\nPSCs achieved a power conversion efficiency (PCE) of 24.61%, demonstrating\nenhanced long-term stability under both light and thermal stress.\nThe developed device retained 92.53% of its initial PCE after 1200\nh of continuous illumination and 88.6% of its initial PCE after 600\nh of 85 °C thermal stability tests, respectively, both conducted\nin N<sub>2</sub> atmospheres.