Enhanced ferromagnetic properties achieved by F-doping in BaFe1-xMnxO3-δ.

Tailoring the crystal structure, spin, and charge state of perovskite oxides through fluorine ion doping is an attractive and effective strategy, which could significantly modify the physical and chemical properties of base oxides. Here, BaFe1-xMnxO3-δ (x = 0, 0.1, 0.2, 0.3) and BaFe1-xMnxO2.9-δF0.1 (x = 0.1, 0.2, 0.3), belonging to 6H-type BaFeO3-δ, are prepared and investigated to evaluate the impact of F- doping. The distortion of crystal structure and the reduced average valence of Mn and Fe confirm the preference for F- substitution in the hexagonal layer, which are found as the key factors for the improved magnetic properties, including ferromagnetic ordering temperature, coercive force, and remanent magnetization. Moreover, the valence reduction of B-site ions and the increased resistance distinctly indicate the expense of electron hole via fluorine doping. This work describes the adjustment of crystal structure, electronic configuration, and ferromagnetic performance by simple F- doping, which provides a prospect for practical magnetic materials.

Zn-doped NiSe2@Ni(OH)2 nanocomposites as binder-free electrodes for asymmetric supercapacitors with impressive performance.

The low stability and poor activities of transition metal selenides (TMSs) in alkaline electrolyte limit their application in supercapacitors. Metal doping and hybridization of various electroactive materials with different properties are utilized to enhance the electrochemical performance of TMSs by optimizing their electronic structure and providing rich electrochemical active sites. Herein, we report a simple two-step hydrothermal method for the growth of Zn-doped NiSe2 and Ni(OH)2 nanocomposites on Ni foam [Zn-NiSe2/Ni(OH)2]. The resulting material delivers high specific capacity (1525.8 C g-1/564.7 mA h g-1 at 6 A g-1 and 1220 C g-1 at 10 A g-1) in a three-electrode system. A Zn-NiSe2/Ni(OH)2//porous carbon (PC) aqueous asymmetric supercapacitor (ASC) was built by utilizing Zn-NiSe2/Ni(OH)2 as the positive electrode and PC as the negative electrode. This Zn-NiSe2/Ni(OH)2//PC ASC shows an energy density of 75.8 W h kg-1 at a power density of 916.1 W kg-1 and achieves a specific capacity retention of 100% after 25 000 cycles at 10 A g-1. These results reveal that the Zn doping and the hybridization of NiSe2 with Ni(OH)2 can obtain impressive electrochemical properties in ASCs.

Ligand Engineering of Inorganic Lead Halide Perovskite Quantum Dots toward High and Stable Photoluminescence.

The ligand engineering of inorganic lead halide perovskite quantum dots (PQDs) is an indispensable strategy to boost their photoluminescence stability, which is pivotal for optoelectronics applications. CsPbX3 (X = Cl, Br, I) PQDs exhibit exceptional optical properties, including high color purity and tunable bandgaps. Despite their promising characteristics, environmental sensitivity poses a challenge to their stability. This article reviews the solution-based synthesis methods with ligand engineering. It introduces the impact of factors like humidity, temperature, and light exposure on PQD's instability, as well as in situ and post-synthesis ligand engineering strategies. The use of various ligands, including X- and L-type ligands, is reviewed for their effectiveness in enhancing stability and luminescence performance. Finally, the significant potential of ligand engineering for the broader application of PQDs in optoelectronic devices is also discussed.