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Three-dimensional halide-based perovskites have emerged as promising semiconducting light harvesters for thin-film solar cell fabrication; however, their intrinsic instability under humidity restricts their potential commercialization. To address such challenges, the development of low-dimensional/layered Dion–Jacobson (DJ) phase perovskites has recently gained substantial attention due to their intriguing environmental stability and competitive power conversion efficiency. In this Review, we have screened and focused our investigation on the DJ phase in layered perovskites for solar cell fabrication, especially elucidation of the active role played by organic spacer cations. We also discuss the possible strategies that can be employed to further push the performance of DJ-based perovskite solar cells.

Three-dimensional bimetallic nanoframes with high spatial diffusivity and surface heterogeneity possess remarkable catalytic activities owing to their highly exposed active surfaces and tunable electronic structure. Here we report a general one-pot strategy to prepare ultrathin octahedral Au 3 Ag nanoframes, with the formation mechanism explicitly elucidated through well-monitored temporal nanostructure evolution. Rich crystalline defects lead to lowered atomic coordination and varied electronic states of the metal atoms as evidenced by extensive structural characterizations. When used for electrocatalytic methanol oxidation, the Au 3 Ag nanoframes demonstrate superior performance with a high specific activity of 3.38 mA cm −2 , 3.9 times that of the commercial Pt/C. More intriguingly, the kinetics of methanol oxidation on the Au 3 Ag nanoframes is counter-intuitively promoted by carbon monoxide. The enhancement is ascribed to the altered reaction pathway and enhanced OH − co-adsorption on the defect-rich surfaces, which can be well understood from the d-band model and comprehensive density functional theory simulations.

Stretchable light‐emitting diodes (LEDs) and electroluminescent capacitors have been reported to potentially bring new opportunities to wearable electronics; however, these devices lack in efficiency and/or stretchability. Here, a stretchable organometal‐halide‐perovskite quantum‐dot LED with both high efficiency and mechanical compliancy is demonstrated. The hybrid device employs an ultrathin (<3 µm) LED structure conformed on a surface‐wrinkled elastomer substrate. Its luminescent efficiency is up to 9.2 cd A−1, which is 70% higher than a control diode fabricated on the rigid indium tin oxide/glass substrate. Mechanical deformations up to 50% tensile strain do not induce significant loss of the electroluminescent property. The device can survive 1000 stretch–release cycles of 20% tensile strain with small fluctuations in electroluminescent performance.