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Nondoped organic light-emitting diodes (OLEDs) are of paramount importance for display and lighting applications owing to their advantages of facile fabrication and outstanding stability. However, nondoped OLEDs achieving extraordinary electroluminescence (EL) performance and low turn-on voltage (

Herein, a N-rich metal-organic framework (MOF) with four kinds of cages, Zn

Constructing high-quality white organic light-emitting diodes (WOLEDs) remains a big challenge because of high demands on the electroluminescence (EL) performance including high efficiency, excellent spectral stability, and low roll-off simultaneously. To achieve effective energy transfer and trap-assisted recombination in the emissive layer, herein, four Ir(III) phosphors, namely

Polyoxometalates (POMs) have a broad array of applied platforms with well-characterized catalysis including photocatalysis to achieve aliphatic C(sp3)-H bond functionalization. However, the reaction mechanism of POMs in organic transformation remains unknown due to the complexity of POM structures. Here, a challenging [W10O32]4-/Ni metallaphotoredox-catalyzed C(sp3)-H arylation of alkane has been investigated by density functional theory (DFT) calculations. The calculation revealed that the superficial active center located in bridged oxygen of *[W10O32]4- is responsible for the abstraction of a foreign hydrogen atom and the activation of a C(sp3)-H bond. Furthermore, we discussed this activated process using the direct activation model of the C(sp3)-H σ-bond to deepen our mechanistic understanding of POM mediated C-H bond activation via the hydrogen atom transfer (HAT) pathway. Specifically, comparing three common mechanisms for nickel catalysis inducing by Ni0, NiI, and NiII to construct a C-C bond, the nickel catalytic cycle induced by the NiI active catalyst is profitable in kinetics and thermodynamics. Finally, a radical mechanism merging the ([W10O32]4--*[W10O32]4--[HW10O32]4--[W10O32]4-) decatungstate reductive quenching cycle, ([HW10O32]4--[H2W10O32]4--[HW10O32]4-) electron relay, and (NiI-NiII-NiI-NiIII-NiI) nickel catalytic cycle is proposed to be favorable. We hope that this work would provide a better understanding of the unique catalytic activity of decatungstate anions for the direct functionalization of the C(sp3)-H bond.

Lead halide perovskites (LHPs) with excellent performance have become promising materials for optoelectrical devices. However, as for the dual-color emission LHPs (DELHPs), the low photoluminescence quantum yield (PLQY) hinders their applications. Herein, a simple low-cost room-temperature post-synthetic modification strategy is used to achieve a near-unity PLQY of DELHPs. It is proven that ZnBr2 plays an important role as an inorganic ligand in reducing surface defects to induce a 95.4% increase in the radiative decay rate and a 99.5% decrease in the nonradiative decay rate in the treated DELHPs compared with the pristine DELHPs. The performance of the blue emission from the surface lattice is greatly improved via the modification of ZnBr2. DELHPs with different ratios of blue and green emissions are obtained by changing the specific surface area and ZnBr2 concentration. The distribution and mechanism of Zn2+ are discussed using the research model based on these DELHPs. The first example of the single-layer dual-color perovskite electroluminescence device is realized from DELHPs. This work provides a new perspective for improving the performance of DELHPs, which will greatly accelerate the development of emission materials of LHPs.

Photocatalytic carbon dioxide reduction (CO2RR) is considered to be a promising sustainable and clean approach to solve environmental issues. Polyoxometalates (POMs), with advantages in fast, reversible, and stepwise multiple-electron transfer without changing their structures, have been promising catalysts in various redox reactions. However, their performance is often restricted by poor thermal or chemical stability. In this work, two transition-metal-modified vanadoborate clusters, [Co(en)2]6[V12B18O54(OH)6]·17H2O (V12B18-Co) and [Ni(en)2]6[V12B18O54(OH)6]·17H2O (V12B18-Ni), are reported for photocatalytic CO2 reduction. V12B18-Co and V12B18-Ni can preserve their structures to 200 and 250 °C, respectively, and remain stable in polar organic solvents and a wide range of pH solutions. Under visible-light irradiation, CO2 can be converted into syngas and HCOO- with V12B18-Co or V12B18-Ni as catalysts. The total amount of gaseous products and liquid products for V12B18-Co is up to 9.5 and 0.168 mmol g-1 h-1. Comparing with V12B18-Co, the yield of CO for V12B18-Ni declines by 1.8-fold, while that of HCOO- increases by 35%. The AQY of V12B18-Co and V12B18-Ni is 1.1% and 0.93%, respectively. These values are higher than most of the reported POM materials under similar conditions. The density functional theory (DFT) calculations illuminate the active site of CO2RR and the reduction mechanism. This work provides new insights into the design of stable, high-performance, and low-cost photocatalysts for CO2 reduction.

The solid-solid conversion of Li2S2 to Li2S is a crucial and rate-controlling step that provides one-half of the theoretical capacity of lithium-sulfur (Li-S) batteries. The catalysts in the Li-S batteries are often useless in the solid-solid conversion due to the poor contact interfaces between solid catalysts and insoluble solid Li2S2. Considering that ultrafine nanostructured materials have the properties of quantum size effects and unconventional reactivities, we design and synthesize for the pomegranate-like sulfur nanoclusters@nitrogen-doped carbon@nitrogen-doped carbon nanospheres (S@N-C@N-C NSs) with a seed-pulp-peel nanostructure. The ultrafine S@N-C subunits (diameter ≈5 nm) and effects of a spatial structure perfectly realize the rapid conversion of ultrafine Li2S2 to Li2S. The S@N-C@N-C seed-pulp-peel NS cathodes exhibit excellent sulfur utilization, superb rate performance (760 mAh g-1 at 10.0 C), and an ultralow capacity decay rate of about 0.016% per cycle over 1000 cycles at 4.0 C. The proposed strategy based on ultrafine nanostructured materials can also inform material engineering in related energy storage and conversion fields.

For the electrochemical reduction of CO2, CO is a crucial single-carbon product and a major intermediate to multicarbon products. Direct dimerization of CO is the most charming channel to C2 products, although the corresponding kinetic energy barrier causes a huge gap compared with other alternative pathways. The effective CO migration among multiple catalytic sites is predominant but has not been fully explored during the C-C bond formation and further protonation processes. Herein, the entirely planar global-minimum Ni2B5 monolayer with multikinds of catalytic sites is selected as an appropriate instance, on which CO can effectively migrate among different types of sites with the highest barrier of 0.64 eV. Most importantly, the computed ultralow barrier of direct *CO dimerization (0.17 eV), the limiting potentials for CH2CH2 (-0.13 V), and CH3CH2OH (-0.17 V) reach the optimal value until now, which all happen on the p-p type of dual-CO adsorption configurations after CO migration. Moreover, the hydrogen reduction side reaction is uncompetitive with the CO electrochemical reduction on all possible adsorption sites. This study demonstrates the significance of CO migration and opens a new avenue for CO reduction to high-density multicarbon products on the surface of catalysts possessing multikinds of catalytic sites.

Recent experimental work reported that visible-light photoredox catalysis coupled with primary sulfonamides and electron-deficient alkenes could efficiently construct C-C bonds at the α-position of primary amine derivatives under mild conditions. Here, a systematic study was conducted to explore the non-negligible excited-state single-electron-transfer (SET) processes and the catalytic cycle. Hydrogen atom transfer (HAT) catalysis containing different site-selective functionalization, involved as a critical process during the reaction, was computationally characterized. The superiorities of iridium-based photoredox catalysts in terms of photoabsorption properties, phosphorescence rates, and electron-transfer rates for SET processes were focused on. In addition, the function of quinuclidine in the entire photocatalytic reaction was also probed. These intrinsic properties and detailed insights into the mechanism are supposed to be helpful to the understanding of the C-C bond functionalization reaction and the future application of the iridium-based photoredox catalyst.

The search for highly stable hydrogen evolution reaction (HER) catalysts with high activity, multiple active sites, and excellent electrical conductivity is crucial to promote the development of hy...

Phytopathogenic fungal infections have become a major threat to agricultural production, food security, and human health globally, and novel antifungal agents with simple chemical scaffolds and high efficiency are needed. In this study, we designed and synthesized 38 8-hydroxyquinoline metal complexes and evaluated their antifungal activities. The results showed that most of the tested compounds possessed remarkable in vitro antifungal activity. Especially, compound 1e exhibited the highest antifungal potency among all target compounds, with EC50 values of 0.0940, 0.125, 2.95, and 5.96 μg/mL, respectively, against Sclerotinia sclerotiorum, Botrytis cinerea, Fusarium graminearum, and Magnaporthe oryzae. Preliminary mechanistic studies had shown that compound 1e might cause mycelial abnormalities of S. sclerotiorum, cell membrane permeability changes, leakage of cell contents, and inhibition of sclerotia formation and germination. Moreover, the results of in vivo antifungal activity of compound 1e against S. sclerotiorum showed that 1e possessed higher curative effects than that of the positive control azoxystrobin. Therefore, compound 1e is expected to be a novel leading structure for the development of new antifungal agents.