Highly efficient blue-emitting three-dimensional (3D) lead−free halide perovskites with excellent stability have attracted worldwide attention. Herein, a doping route was adopted to incorporate Sb 3+ ions into the Cs 2 NaInCl 6 for decorating the electronic band structure. Due to the moderate electron−phonon coupling, the Sb 3+ -doped Cs 2 NaInCl 6 double perovskites showed a narrow and relatively unusual blue emission of self-trapped excitons (STEs). Density functional theory (DFT) calculation indicated that the doped Sb 3+ ions could break the parityforbidden transition rule and modulate the density of state (DOS) population effectively to boost the PLQY of STEs drastically. The optimized Sb 3+ :Cs 2 NaInCl 6 exhibited a PLQY of up to 75.89% and excellent stability under the consecutive illumination of 365 nm UV light for 1000 h. This kind of highly efficient lead-free Sb 3+ -doped Cs 2 NaInCl 6 double perovskites may overcome the bottlenecks of severe toxicity and insufficient stability and therefore have an extensive application in the scarce blue photonic and optoelectronic fields.

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Double perovskites exhibit low toxicity, intrinsic thermodynamic stability, and small carrier effective mass. Herein, a novel doping route was adopted to incorporate Mn ions into Cs2Na1–x Ag x BiCl6 double perovskites for engineering the band gap and tailoring the energy transfer. The as-prepared Cs2Na1–x Ag x BiCl6 (0 < x < 1) exhibited excellent photoluminescence and a broad self-trapped exciton (STE) band from 500 to 900 nm, which exhibited an abnormal emission peak blue shift with increasing temperature. For Mn-doped Cs2Na1–x Ag x BiCl6, the two photoluminescence (PL) bands from d–d transition emission of Mn ions and STEs were always observed simultaneously in the PL window. The distinct energy-transfer channel from the Mn2+ ion guest to the double-perovskite host resulted in the dominant Mn2+ emission. Our results will be helpful for further understanding the nature of the photophysics of double perovskites.

Zero-dimensional (0D) metal halides are in a blossoming status for their fascinating optoelectronic properties. Herein, an antimony-based metal halide of (C 16 H 28 N) 2 -SbCl 5 (C 16 H 28 N + = benzyltripropylammonium cations), where the isolated [SbCl 5 ] 2− clusters are surrounded by C 16 H 28 N + to form a 0D square-pyramidal structure, was synthesized and investigated. The (C 16 H 28 N) 2 SbCl 5 exhibited a broadband orange emission at 633 nm upon the low-energy irradiation (400 nm) with a near-unity photoluminescence quantum efficiency (97.8%). Interestingly, (C 16 H 28 N) 2 SbCl 5 showed an additional emission peak at 477 nm upon the higher-energy irradiation (300 nm), which is attributed to the transformation of the doublet of spin-orbit couplings into two independent self-trapped excitons (STEs). Temperaturedependent Raman spectra clearly revealed the characteristics of multi-phonon coupling, demonstrating a strong anharmonic electron-phonon interaction in (C 16 H 28 N) 2 SbCl 5 . Temperature-dependent emission spectra and density functional theory results illustrated that the observed dual-band emission originated from singlet and triplet STEs in [SbCl 5 ] 2− units. Combined with the efficient emission and excellent stability of (C 16 H 28 N) 2 SbCl 5 , a stable white-light-emitting diode with an ultra-high color rendering index of 96.6 was fabricated.

Various Mn 2 O 3 hollow structures, such as spheres, cubes, ellipsoids, and dumbbells have been synthesized through the following process: The surfaces of the prepared MnCO 3 microspheres, microcubes, and microellipsoids were oxidized by KMnO 4 to form a core/shell structure. Similarly, the surface of a dumbbelllike MnCO 3 intermediate can also be oxidized by KMnO 4 . As the MnCO 3 or MnCO 3 intermediate cores were dissolved by acid, the MnO 2 shells were formed. Calcining these MnO 2 shells at 500 °C, polycrystalline Mn 2 O 3 hollow structures were obtained. The morphologies of these hollow structures were similar to their precursors. The as-prepared hollow Mn 2 O 3 materials were used as adsorbents in water treatment, and the hollow Mn 2 O 3 spheres, cubes, ellipsoids, and dumbbells could respectively remove about 77%, 83%, 81%, and 78% of phenol.

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Phase pure titanium diboride (TiB2) powder of 100‐200 nm was synthesized from TiO2 and B2O3 using a molten‐salt‐assisted magnesiothermic reduction technique. The effects of salt type, Mg amount, reaction temperature, and TiO2 raw materials on the synthesis process were examined and the relevant reaction mechanisms discussed. Among the three chloride salts (NaCl, KCl, and MgCl2), MgCl2 showed the best accelerating‐effect. To synthesize phase pure TiB2, 20 mol% excessive Mg had to be used to compensate for the evaporation loss of Mg. Particle shape and size of raw material TiO2 showed little effect on the formation of TiB2 and its shape and size, suggesting that relatively cheaper and coarser TiO2 raw materials could be used for low‐temperature synthesis of TiB2 fine particles. The “dissolution‐precipitation” mechanism governed the overall molten salt synthesis process.