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The spontaneously formed uncoordinated Pb 2 + defects usually make the perovskite films demonstrate strong n-type with relatively lower carrier diffusion length and serious non-radiative recombination energy loss. In this work, we adopt different polymerization strategies to construct three-dimensional passivation frameworks in the perovskite layer. Thanks to the strong C�N•••Pb coordination bonding and the penetrating passivation structure, the defect state density is obviously reduced, accompanied by a significant increase in the carrier diffusion length. Additionally, the reduction of iodine vacancies also changed the Fermi level of the perovskite layer from strong n-type to weak n-type, which substantially promotes the energy level alignment and carrier injection efficiency. As a result, the optimized device achieved an efficiency exceeded 24 % (the certified efficiency is 24.16 %) with a high open-circuit voltage of 1.194 V, and the corresponding module achieved an efficiency of 21.55 %.

The unavoidable iodine loss in the perovskite layer is closely related to carrier non‐radiative and device degradation. During the post‐annealing process, the fragile PbI bond is easy to break, leading to the formation of iodine vacancies and inducing stress‐driven structure collapse. Herein, a PbI6 octahedra stabilization strategy via building robust grain boundary modification networks is developed. The introduction of conjugated structure into amides can significantly enhance their anchoring ability with PbI units, while the π–π stacking effect of benzamide enables a passivation network with polymer‐like effect. This is well evidenced by the excellent properties in eliminated iodine loss and stabilized perovskite lattice. Therefore, benzamide modification not only transform the perovskite films from n‐type to p‐type by suppressing the iodine vacancy‐doping effect, but also reduces defect density, ultimately bringing the perovskite layer longer carrier diffusion length and better charge injection efficiency. Finally, the benzamide modified devices realize both high power conversion efficiency of 24.78% and excellent operating stability. Of particular note, the module efficiency with 14 cm2 active area is over 21%.

Solvents employed for perovskite film fabrication not only play important roles in dissolving the precursors but also participate in crystallization process. High boiling point aprotic solvents with O-donor ligands have been extensively studied, but the formation of a highly uniform halide perovskite film still requires the participation of additives or an additional step to accelerate the nucleation rate. The volatile aliphatic methylamine with both coordinating ligands and hydrogen protons as solvent or post-healing gas facilitates the process of methylamine-based perovskite films with high crystallinity, few defects, and easy large-scale fabrication as well. However, the attempt in formamidinium-containing perovskites is challenged heretofore. Here, we reveal that the degradation of formamidinium-containing perovskites in aliphatic amines environment results from the transimination reaction of formamidinium cation and aliphatic amines along with the formation of ammonia. Based on this mechanism, ammonia is selected as a post-healing gas for a highly uniform, compact formamidinium-based perovskite films. In particular, low temperature is proved to be crucial to enable formamidinium-based perovskite materials to absorb enough ammonia molecules and form a liquid intermediate state which is the key to eliminating voids in raw films. As a result, the champion perovskite solar cell based on ammonia post-healing achieves a power conversion efficiency of 23.21% with excellent reproducibility. Especially the module power conversion efficiency with 14 cm2 active area is over 20%. This ammonia post-healing treatment potentially makes it easier to upscale fabrication of highly efficient formamidinium-based devices.

Tin−lead (Sn−Pb) alloyed perovskites are promising candidates for next-generation photovoltaics due to their appropriate bandgaps for multijunction tandem solar cells, which can potentially overcome the Shockley-Queisser limit. However, their power conversion efficiency (PCE) and stability are still impeded by the poor absorber quality and defects caused by the oxidation of Sn 2+ . Here, we introduced trimethylsulfoxonium iodide (TMSI) as an additive along with SnF 2 to fabricate Sn−Pb perovskite films with enlarged grains and improved film quality. TMSI restrained the oxidation of Sn 2+ through molecular interactions, reducing the formation of detrimental Sn vacancies. As a result, a highly oriented Sn−Pb alloyed perovskite with a lower defect density was obtained, along with suppressed ion migration. The TMSI-treated Sn−Pb-based devices exhibited a champion PCE of 22.6% and outstanding stability, retaining 83% of their original efficiency after 6000 h of storage under a N 2 atmosphere and maintaining 88% of their initial value after 1200 h of continuous one-sun illumination.

Metal‐cation defects and halogen‐anion defects in perovskite films are critical to the efficiency and stability of perovskite solar cells (PSCs). In this work, a random polymer, poly(methyl methacrylate‐co‐acrylamide) (PMMA‐AM), was synthesized to serve as an interfacial passivation layer for synergistically passivating the under‐coordinated Pb2+ and anchor the I‐ of the [PbI6]4− octahedron. Additionally, the interfacial PMMA‐AM passivation layer cannot be destroyed during the hole transport layer deposition because of its low solubility in chlorobenzene. This passivation leads to an enhancement in the open‐circuit voltage from 1.12 to 1.22 V and improved stability in solar cell devices, with the device maintaining 95 % of the initial power conversion efficiency (PCE) over 1000 h of maximum power point tracking. Additionally, a large‐area solar cell module was fabricated using this approach, achieving a PCE of 20.64 %.

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Aiming to regulate the crystallization and reduce defects of perovskite film, an organic small molecule with sulfonyl, 3-ethylbenzo[d]isothiazole 1,1-dioxide (PSAD), is introduced into perovskite precursor solution. A variety of characterizations...