Two-dimensional (2D) ferromagnetic materials with high spin polarization are highly desirable for spintronic devices. 2D Janus materials exhibit novel properties due to their broken symmetry. However, the electronic structure and magnetic properties of 2D Janus magnetic materials with high spin polarization are still unclear. Inspired by the successful synthesis of a ferromagnetic FeCl2 monolayer and 2D Janus MoSSe and WSSe, we systematically study the electronic structure and magnetic properties of Janus FeXY (X, Y = Cl, Br, and I, X ≠ Y) monolayers. Based on the Goodenough–Kanamori–Anderson theory, the ferromagnetism stems from the superexchange interaction mediated by Fe–X/Y–Fe bonds. The band gaps of spin-up channels are large enough (>4 eV) to prevent spin flipping, which is beneficial for spintronic devices. Additionally, the sizable magnetocrystalline anisotropy energy (MAE) indicates that Janus FeXY monolayers are suitable for information storage. More importantly, the half-metallic character is still kept in Janus FeXY monolayers, and their magnetic properties are enhanced by the biaxial compressive strain. The MAE of FeClI and FeBrI increases by 1 order of magnitude, and the Curie temperature of FeXY monolayers enhances by 100%. These results provide an example of the 2D Janus half-metallic materials and enrich the 2D magnetic material library.

IntroductionConverting solar light into chemical energy such as hydrogen via artificial photosynthesis is a promising approach to address Solar-driven water splitting is in urgent need for sustainable energy research, for which accelerating oxygen evolution kinetics along with charge migration is the key issue. Herein, Mn 3+ within π-conjugated carbon nitride (C 3 N 4 ) in form of Mn-N-C motifs is coordinated. The spin state (e g orbital filling) of Mn centers is regulated by controlling the bond strength of Mn-N. It is demonstrated that Mn serves as intrinsic oxygen evolution reaction (OER) site and the kinetics is dependent on its spin state with an optimized e g occupancy of ≈0.95. Specifically, the governing role of e g occupancy originates from the varied binding strength between Mn and OER intermediates. Benefiting from the rapid spin state-mediated OER kinetics, as well as extended optical absorption (to 600 nm) and accelerated charge separation by intercalated metal-to-ligand state, Mn-C 3 N 4 stoichiometrically splits pure water with H 2 production rate up to 695.1 µmol g −1 h −1 under simulated sunlight irradiation (AM1.5), and achieves an apparent quantum efficiency of 4.0% at 420 nm, superior to most solid-state based photocatalysts to date. This work for the first time correlates photocatalytic redox kinetics with the spin state of active sites, and suggests a nexus between photocatalysis and spin theory.

Valley degree of freedom of Bloch electrons provides a proper platform to realize information storage and processing. Using first-principles calculations, we propose that FeClBr monolayer is a ferromagnetic semiconductor with...

We developed type-II core−shell nanocrystals (NCs) with a chiral low-dimensional perovskite shell and an achiral 3D MAPbBr 3 core. The core−shell NCs exhibit spin-polarized luminescence at the first excitation band of the achiral core, which is due to the chiral-induced spin selectivity (CISS) effect-governed spin-dependent shell-to-core electron transportation and the subsequent electron− hole recombination in the core. The preferred spin state of the transferred electrons is determined by the handness of the chiral shell. For the core−shell NCs film, a photoluminescence quantum yield (PLQY) of 54% and a circularly polarized luminescence (CPL) with a maximum |g lum | of 4.0 × 10 −3 are obtained at room temperature. Finally, we achieved a spin-polarized light-emitting diode (spin-LED), affording a circularly polarized electroluminescence (CP-EL) with a |g CP-EL | of 6.0 × 10 −3 under ambient conditions.

Photothermocatalytic CO 2 reduction as the channel of the energy and environmental issues resolution has captured persistent attention in recent years. In 2 O 3 has been prompted to be a potential photothermal catalyst in this sector on account of its unique physicochemical properties. However, different from the metal-based photothermal catalyst with the nature of efficient light-to-thermal conversion and H 2 dissociation, the wide-bandgap semiconductor needs to be modified to possess wide-wavelength-range absorption and the active surface. It remains a challenge to achieve the two aims simultaneously via a single material modulation approach. In this study, one strategy of carbon doping can empower In 2 O 3 with two advantageous modifications. Carbon doping can reduce the formation energy of oxygen vacancy, which induces the generation of oxygen-vacancy-riched material. The introduction of oxygen defect levels and carbon doping levels in the bandgap of In 2 O 3 significantly reduces this bandgap, which endows it full-spectral and intensive solar light absorption. Therefore, the carbon doped In 2 O 3 achieves effective light-to-thermal conversion and delivers a 123.6 mmol g -1 h -1 of CO generation rate with near-unity selectivity, as well as prominent stability in photothermocatalytic CO 2 reduction.