Lead‐based perovskite light‐emitting diodes (PeLEDs) have exhibited excellent purity, high efficiency, and good brightness. In order to develop nontoxic, highly luminescent metal halide perovskite materials, tin, copper, germanium, zinc, bismuth, and other lead‐free perovskites have been developed. Here, a novel 0D manganese‐based (Mn‐based) organic–inorganic hybrid perovskite with the red emission located at 629 nm, high photoluminescence quantum yield of 80%, and millisecond level triplet lifetime is reported. When applied as the emissive layer in the PeLEDs, the maximum recording brightness of devices after optimization is 4700 cd m−2, and the peak external quantum efficiency is 9.8%. The half‐life of the device reaches 5.5 h at 5 V. The performance and stability of Mn‐based PeLEDs are one order of magnitude higher than those of other lead‐free PeLEDs. This work clearly shows that the Mn‐based perovskite will provide another route to fabricate stable and high‐performance lead‐free PeLEDs.

The formability of antiperovskite [MX4]­XA3-type (A­(I) = alkali metals; M­(II) = transition metals; X = Cl, Br, I) can be predicted by building the analysis theory. To validate the prediction model, a series of cesium–manganese antiperovskite single crystals with different halogen mixing ratios were synthesized, which not only have [MX4]­XA3-type structures but also are ideal luminescent materials. As the most pure green emission fluorescent antiperovskite, [MnCl2Br2]­BrCs3 shows 520 nm emission with the high photoluminescence quantum yield (93.5%) at room temperature and ultrastable luminescent color from 77 to 523 K due to the strict confinement of high-density luminescent centers. By fabricating the perovskite film with the double-source thermal evaporation method, the first all-inorganic cesium–manganese halide antiperovskite light-emitting diode is reported, with maximum external quantum efficiency up to 12.5%, maximum luminance up to 3990 cd m–2, and half-life of 756 min operated at 5.0 V.

The perovskite light‐emitting diode (PeLED) based on lead has the advantages of excellent purity, high efficiency, and good brightness. In order to develop a highly luminescent and deep blue lead halide perovskite light emitting diode, here, a two‐dimensional layered lead perovskite owning the high deep blue photoluminescence quantum yield 80% at 445 nm is reported. In addition, the maximum recording brightness and the peak external quantum efficiency of the PeLED is 1315 cd m−2 and 3.08%, respectively, which outdoes that of previously reported deep blue lead PeLEDs. The half‐life of the device reaches 3.5 h at 5 V. This work clearly shows that the layered lead perovskite will provide a route to fabricate stable and high‐performance deep blue emission PeLEDs.

The Pd/TiO 2 catalysts with varying Pd nanoparticle sizes are used to study the control of selectivity toward the hydrogenation of 3-nitrostyrene (3-NS). Our results show the selectivities of 3-vinylanilline (3-VA) rise by decreasing the particle size, while the selectivity of 3-ethylnitrobenzene (3-EN) is the opposite. However, over the Pd/SiO 2 catalysts, 3-EN moieties are the dominant product regardless of their differences in particle size. We find that the electronic interactions between Pd NPs and the TiO 2 support rise by decreasing particle size, as a result, creating more admetals on the Pd NPs in contact with TiO 2 , which favorably adsorb the nitro group of 3-NS, thus resulting in enhanced selectivity of 3-VA. However, the classical strong metal−support interactions (SMSI) induced by reduction at elevated temperatures play no significant role in the controlling of selectivities of 3-VA and 3-EN. The SiO 2 -supported Pd NPs without electronic metal−support interactions (EMSIs) prefer the reduction of the vinyl group of 3-NS. This work underlines the importance of EMSI governing the selectivity for hydrogenation of unsaturated nitroarene reactions.