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Chirality‐induced spin selectivity observed in chiral 2D organic–inorganic hybrid perovskite holds promise to achieve spin‐dependent electrochemistry. However, conventional chiral 2D perovskites suffer from low conductivity and hygroscopicity, limiting electrochemical performance and operational stability. Here, a cutting‐edge material design is introduced to develop a stable and efficient chiral perovskite‐based spin polarizer by employing fluorinated chiral cation. The fluorination approach effectively promotes the charge carrier transport along the out‐of‐plane direction by mitigating the dielectric confinement effect within the multi‐quantum well‐structured 2D perovskite. Integrating the fluorinated cation incorporated spin polarizer with BiVO4 photoanode considerably boosts the photocurrent density while reducing overpotential through a spin‐dependent oxygen evolution reaction. Furthermore, the hydrophobic nature of fluorine in spin polarizer endows operational stability to the photoanode, extending the durability by 280% as compared to the device with non‐fluorinated spin polarizer. [ABSTRACT FROM AUTHOR]

Chiral perovskites have emerged as promising next‐generation materials for polarization detection due to their excellent circularly polarized light (CPL) detection capabilities. However, they suffer from a low chiroptical response when fabricated as a polycrystalline thin film, limiting their potential range of applications. Herein, it is demonstrated that antisolvent dripping during the spin‐coating process can effectively improve the chiroptical properties of polycrystalline chiral perovskite thin films. Systematic analysis with different antisolvents reveals that the highly polar antisolvent chloroform interacts with dimethyl sulfoxide molecules via hydrogen bonding. This strong hydrogen bonding suppresses the formation of intermediate and secondary phases and accelerates the crystallization of chiral 1D perovskites, thus reducing the density of the iodine vacancies inside the perovskite thin films. The lower density of iodine vacancies also intensifies the asymmetric tilting inorganic distortion of PbI6 octahedrons, enhancing the chiroptical response of the fabricated chiral perovskite material. Photodetectors based on the chloroform‐treated chiral perovskite films achieve a remarkably high distinguishability of 0.31, outperforming previously reported photodetectors based on the chiral perovskites. The fabricated photodetectors also exhibit outstanding responsivity and detectivity with enhanced operational stability. [ABSTRACT FROM AUTHOR]

Recently, lead halide perovskites have attracted significant attention as promising absorber materials for photoelectrochemical (PEC) solar water splitting. However, charge‐accumulation‐induced ion migration at the interface causes perovskite degradation and efficiency loss. To suppress the charge accumulation and improve the PEC performance of the perovskite photoanode, a simple interface engineering is proposed by decorating the SnO2/perovskite interface with a mixture of polyethylenimine ethoxylated (PEIE) and chlorobenzenesulfonic acid (CBSA). The mixed CBSA+PEIE treatment effectively passivates the oxygen vacancies in SnO2 and adjusts the band alignment between SnO2 and the perovskite. The synergistic effects of the mixture treatment facilitate an effective carrier extraction at the SnO2/perovskite interface, enhance the PEC performance, and improve the stability of the device. The perovskite photoanode exhibits an impressive applied bias photon‐to‐current efficiency of 12.9% with an outstanding durability for 225 h. Furthermore, an unbiased solar water splitting is achieved using all the perovskite photoelectrodes, resulting in a remarkable unassisted solar‐to‐hydrogen efficiency of 10.9% and a continuous 22 h stable operation. [ABSTRACT FROM AUTHOR]

Oxygen evolution reaction (OER) as a half‐anodic reaction of water splitting hinders the overall reaction efficiency owing to its thermodynamic and kinetic limitations. Iodide oxidation reaction (IOR) with low thermodynamic barrier and rapid reaction kinetics is a promising alternative to the OER. Herein, we present a molybdenum disulfide (MoS2) electrocatalyst for a high‐efficiency and remarkably durable anode enabling IOR. MoS2 nanosheets deposited on a porous carbon paper via atomic layer deposition show an IOR current density of 10 mA cm–2 at an anodic potential of 0.63 V with respect to the reversible hydrogen electrode owing to the porous substrate as well as the intrinsic iodide oxidation capability of MoS2 as confirmed by theoretical calculations. The lower positive potential applied to the MoS2‐based heterostructure during IOR electrocatalysis prevents deterioration of the active sites on MoS2, resulting in exceptional durability of 200 h. Subsequently, we fabricate a two‐electrode system comprising a MoS2 anode for IOR combined with a commercial Pt@C catalyst cathode for hydrogen evolution reaction. Moreover, the photovoltaic–electrochemical hydrogen production device comprising this electrolyzer and a single perovskite photovoltaic cell shows a record‐high current density of 21 mA cm–2 at 1 sun under unbiased conditions. [ABSTRACT FROM AUTHOR]

Designing an appropriate oxygen evolution reaction (OER) catalyst for photoelectrochemical (PEC) water splitting is an urgent issue for providing high-efficiency solar to hydrogen energy production. Transition metals have been central to OER catalyst research due to their plentifulness and specific electronic structure, but overcoming their water oxidation limits, including high overpotential and sluggish kinetics, remains challenging. The effective usage of noble metals for the OER, such as an intentional introduction of low-concentration noble metals into earth-abundant materials, can complement the limited reserve of noble metals and largely enhance the entire efficiency of solar water oxidation. Herein, we developed an OER photoelectrode of Au-incorporated NiFe layered double hydroxide (LDH) placed on a strong light absorber n-type silicon (Au-NiFe LDH/n-Si). With a minimal Au content of 2.7% in the catalyst structure, synergistic effects between noble metal Au and transition metal-based NiFe LDH notably accelerated the OER kinetics while stabilizing the Si-based photoanode structure in corrosive alkaline electrolyte. Optimally fabricated Au-NiFe LDH through a facile two-step electrodeposition process on n-Si exhibited a high saturated photocurrent density of ∼37 mA cm−2, and the saturated photocurrent density could be reached at an early underpotential point of 1.2 V vs. RHE. Moreover, it operated for ∼50 hours in pH 11.5 electrolyte, showing 5 times higher stability than NiFe LDH/n-Si under the same alkaline conditions. One step further, a 1/48 decrease in recombination kinetics could be achieved through doping Au atoms into NiFe LDH, revealing the efficacious defect site passivation effect with the minimum amount of noble metal usage. [ABSTRACT FROM AUTHOR]