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In the pursuit of highly efficient perovskite solar cells, spiro‐OMeTAD has demonstrated recorded power conversion efficiencies (PCEs), however, the stability issue remains one of the bottlenecks constraining its commercial development. In this study, we successfully synthesize a novel self‐polymerized spiro‐type interfacial molecule, termed v‐spiro. The linearly arranged molecule exhibits stronger intermolecular interactions and higher intrinsic hole mobility compared to spiro‐OMeTAD. Importantly, the vinyl groups in v‐spiro enable in situ polymerization, forming a polymeric protective layer on the perovskite film surface, which proves highly effective in suppressing moisture degradation and ion migration. Utilizing these advantages, poly‐v‐spiro‐based device achieves an outstanding efficiency of 24.54 %, with an enhanced open‐circuit voltage of 1.173 V and a fill factor of 81.11 %, owing to the reduced defect density, energy level alignment and efficient interfacial hole extraction. Furthermore, the operational stability of unencapsulated devices is significantly enhanced, maintaining initial efficiencies above 90 % even after 2000 hours under approximately 60 % humidity or 1250 hours under continuous AM 1.5G sunlight exposure. This work presents a comprehensive approach to achieving both high efficiency and long‐term stability in PSCs through innovative interfacial design. [ABSTRACT FROM AUTHOR]

Although the power conversion efficiency values of perovskite solar cells continue to be refreshed, it is still far from the theoretical Shockley-Queisser limit. Two major issues need to be addressed, including disorder crystallization of perovskite and unbalanced interface charge extraction, which limit further improvements in device efficiency. Herein, we develop a thermally polymerized additive as the polymer template in the perovskite film, which can form monolithic perovskite grain and a unique "Mortise-Tenon" structure after spin-coating hole-transport layer. Importantly, the suppressed non-radiative recombination and balanced interface charge extraction benefit from high-quality perovskite crystals and Mortise-Tenon structure, resulting in enhanced open-circuit voltage and fill-factor of the device. The PSCs achieve certified efficiency of 24.55% and maintain >95% initial efficiency over 1100 h in accordance with the ISOS-L-2 protocol, as well as excellent endurance according to the ISOS-D-3 accelerated aging test. Disorder crystallization of perovskite and unbalanced charge extraction limit the performance of perovskite solar cells. Here, the authors develop self-polymerizing additive to form monolithic perovskite grains with mortise-tenon structure, achieving efficiency over 24% and long device stability. [ABSTRACT FROM AUTHOR]

Recently, organic–inorganic metal halide perovskite solar cells (PSCs) have achieved rapid improvement, however, the efficiencies are still behind the Shockley–Queisser theory mainly due to their high energy loss (ELOSS) in open‐circuit voltage (VOC). Due to the polycrystalline nature of the solution‐prepared perovskite films, defects at the grain boundaries as the non‐radiative recombination centers greatly affect the VOC and limit the device efficiency. Herein, poly(vinylidene fluoride) (PVDF) is introduced as polymer‐templates in the perovskite film, where the fluorine atoms in the PVDF network can form strong hydrogen‐bonds with organic cations and coordinate bonds with Pb2+. The strong interaction between PVDF and perovksite enables slow crystal growth and efficient defect passivation, which effectively reduce non‐radiation recombination and minimize ELOSS of VOC. PVDF‐based PSCs achieve a champion efficiency of 24.21% with a excellent voltage of 1.22 V, which is one of the highest VOC values reported for FAMAPb(I/Br)3‐based PSCs. Furthermore, the strong hydrophobic fluorine atoms in PVDF endow the device with excellent humidity stability, the unencapsulated solar cell maintain the initial efficiency of >90% for 2500 h under air ambient of ≈50% humid and a consistently high VOC of 1.20 V. [ABSTRACT FROM AUTHOR]