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Interfacial lattice mismatch and adverse reaction are the key issues hindering the development of nickel oxide (NiOx)‐based inverted perovskite solar cells (PVSCs). Herein, a p‐chlorobenzenesulfonic acid (CBSA) self‐assembled small‐molecule (SASM) is adopted to anchor NiOx and perovskite crystals to endow dual‐passivation. The chlorine terminal of SASMs can provide growth sites for perovskite, leading to interfacial strain release. Meanwhile, the sulfonic acid group from SASMs can passivate surface defects of NiOx, conducive to charge carrier extraction. In addition, the self‐assembled layer inhibits the adverse interfacial reaction by preventing NiOx contact with perovskite. Therefore, the NiOx/CBSA‐based PVSCs obtain a champion power conversion efficiency (PCE) of 21.8%. Of particular note, the unencapsulated devices can retain above 80% of their initial PCE values after storage in a nitrogen atmosphere for 3000 h, in air with a relative humidity of 50–70% for 1000 h, and heating at 85 °C for 800 h, respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] • The interfacial redox reaction between NiO x and perovskite is obstructed. • SaC-100 is developed as a modifier layer in NiO x -based perovskite solar cells. • SaC-100 can efficiently reduce the open-circuit voltage loss of device. • SaC-100 can inhibit perovskite decomposition ascribed from interfacial reaction. In NiO x -based perovskite solar cells (PVSCs), the interfacial redox reaction between Ni3+ (on the surface of NiO x) and A-site cation salt (MAI in perovskite precursor solution) is invariably ignored. This adverse reaction will generate PbI 2 -rich hole extraction barriers at the NiO x -perovskite interface, which limits hole transmission and increases charge recombination, thus resulting in open-circuit voltage (V oc) loss. Furthermore, it will accelerate perovskite degradation by deprotonating the precursor amine and oxidizing iodide to interstitial iodine, which induces the severe instability of devices. Herein, a physical separation strategy by introducing a modifier layer to obstruct the detrimental reaction is explored. The results demonstrate that the trimethylolpropane tris(2-methyl-1-aziridinepropionate) (SaC-100) depositing onto NiO x can suppress the reaction between Ni3+ and MAI to endow the improvement of conductivity and reduction of interfacial defects, thus reducing V oc loss and enhancing device stability. Moreover, the interfacial energy level alignment and the morphology of perovskite are also optimized. As a result, the PVSCs device based on NiO x /SaC-100 presents the best power conversion efficiency (PCE) of 20.21% with a superior V oc value of 1.12 V. Furthermore, the device shows better light and thermal stability because of the hindering effect and defect passivation effect of SaC-100. [ABSTRACT FROM AUTHOR]

Lead‐free 2D antimony‐based halide perovskites with excellent optoelectronic properties, low toxicity, and good intrinsic stability are promising for photovoltaic devices. However, the power conversion efficiency (PCE) of antimony‐based perovskite solar cells (PSCs) is still lower than 3% due to the poor crystallinity and random orientation. Herein, it is found that the Cs3Sb2ClxI9‐x films prepared by adding methylamine chloride as an additive to the precursor solution can form a mixed intermediate phase with 0D dimer phase and 2D layered phase after low pressure treatment. During the annealing process, the 0D dimer phase will completely transition to 2D layered phase due to the partial replacement of I by Cl. Compared to adding SbCl3 directly, this method considerably increases the crystallinity of Cs3Sb2IxCl9‐x films. The obtained films have a preferential orientation along the (201) direction, which is beneficial for charge carrier transportation. Consequently, the champion device shows a PCE of 3.2%, which is one of the highest efficiencies achieved for inorganic Sb‐based PSCs with the n‐i‐p architecture to date. [ABSTRACT FROM AUTHOR]