Latest ArticlesThermally activated delayed fluorescence (TADF) materials driven by a through-space charge transfer (TSCT) mechanism have garnered wide interest. However, access of TSCT-TADF molecules with long-wavelength emission remains a formidable challenge. In this study, we introduce a novel V-type D-A-D-A' emitter, Trz-mCzCbCz, by using a carborane scaffold. This design strategically incorporates carbazole (Cz) and 2,4,6-triphenyl-1,3,5-triazine (Trz) as donor and acceptor moieties, respectively. Theoretical calculations alongside experimental validations affirm the typical TSCT-TADF characteristics of this luminogen. Owing to the unique structural and electronic attributes of carboranes, Trz-mCzCbCz exhibits an orange-red emission, markedly diverging from the traditional blue-to-green emissions observed in classical Cz and Trz-based TADF molecules. Moreover, bright emission in aggregates was observed for Trz-mCzCbCz with absolute photoluminescence quantum yield (PLQY) of up to 88.8%. As such, we have successfully fabricated five organic light-emitting diodes (OLEDs) by utilizing Trz-mCzCbCz as the emitting layer. It is important to note that both the reverse intersystem crossing process and the TADF properties are profoundly influenced by host materials. The fabricated OLED devices reached a maximum external quantum efficiency (EQE) of 12.7%, with an emission peak at 592 nm. This represents the highest recorded efficiency for TSCT-TADF OLEDs employing carborane derivatives as emitting layers.
The development of high-performance carbon-based composite hosts plays decisive roles in the electrochemistry of lithium sulfur batteries. Herein, a novel metal-ion induced gelation self-assembly technology is reported to construct sodium alginate carbon (SAC) based polar hierarchical carbon composites with cross-linked network architecture and in-situ co-grown cross-linked polar nanoparticles. Interestingly, it shows high versatility to an extensive array of materials including metals, alloys, and metallic oxides. As a representative, NiCo alloy nanoparticles are chosen to obtain the SAC/NiCo composite host for sulfur in LSBs, which possess superior physical/chemical adsorption capabilities and catalytic conversion kinetics to polysulfide in virtue of synergistic interaction between the hierarchical pore structures and NiCo catalyst. The designed SAC/NiCo-S cathode shows superior electrochemical performance with excellent rate capacity (2 C: 693.5 mAh/g) and enhanced cycling stability (764.3 mAh/g at 0.1 C after 240 cycles). This work provides a straightforward approach for fabricating multifunctional carbon composites with adjustable component for advanced energy storage system.
The bicarbonate-formate (HCO3− – HCO2−) interconversion provides a promising cycle for a conveniently accessible hydrogen storage system via reversible dehydrogenation and hydrogenation processes. Existing catalytic systems often use organic solvents, tedious optimization as well as manipulation of pH values, solvent, pressure and various additives. Herein, we present an operational, robust, safe and cost-effective catalytic system for hydrogen storage and liberation. We have established a unique catalytic system with two different solid organometallic assemblies (NHC-Ru and NHC-Ir) that facilitate the reversible transformation between sodium formate and bicarbonate in aqueous solutions collaboratively and efficiently. Notably, the NHC-Ru catalyst is privileged for the hydrogenation of sodium bicarbonate, whereas the NHC-Ir component enables the dehydrogenation of sodium formate, all in a single reaction vessel. What sets this system apart is its simplicity. The H2 discharging and recharging is simply regulated by heating the mixture with or without H2. Remarkably, this process requires no extra additives or supplementary treatments. Moreover, the reversible hydrogen storage system is durable and can be reused for over 30 cycles without a discernible decline in activity and selectivity. The strategic paradigm in this study shows significant practical potential in hydrogen fuel cell applications.
Histopathological analysis of chronic wounds is crucial for clinicians to accurately assess wound healing progress and detect potential malignancy. However, traditional pathological tissue sections require specific staining procedures involving carcinogenic chemicals. This study proposes an interdisciplinary approach merging materials science, medicine, and artificial intelligence (AI) to develop a virtual staining technique and intelligent evaluation model based on deep learning for chronic wound tissue pathology. This innovation aims to enhance clinical diagnosis and treatment by offering personalized AI-driven therapeutic strategies. By establishing a mouse model of chronic wounds and using a series of hydrogel wound dressings, tissue pathology sections were periodically collected for manual staining and healing assessment. We focused on leveraging the pix2pix image translation framework within deep learning networks. Through CNN models implemented in Python using PyTorch, our study involves learning and feature extraction for region segmentation of pathological slides. Comparative analysis between virtual staining and manual staining results, along with healing diagnosis conclusions, aims to optimize AI models. Ultimately, this approach integrates new metrics such as image recognition, quantitative analysis, and digital diagnostics to formulate an intelligent wound assessment model, facilitating smart monitoring and personalized treatment of wounds. In blind evaluation by pathologists, minimal disparities were found between virtual and conventional histologically stained images of murine wound tissue. The evaluation used pathologists' average scores on real stained images as a benchmark. The scores for virtual stained images were 71.1% for cellular features, 75.4% for tissue structures, and 77.8% for overall assessment. Metrics such as PSNR (20.265) and SSIM (0.634) demonstrated our algorithms' superior performance over existing networks. Eight pathological features such as epidermis, hair follicles, and granulation tissue can be accurately identified, and the images were found to be more faithful to the actual tissue feature distribution when compared to manually annotated data.
Manganese dioxide (MnO2) electrode material possesses the advantages of high energy density, structural diversity and high modification potential. This allows it become one of the important cathodes for aqueous zinc ion battery. However, the applications are limited by the poor electrical conductivity, narrow layer spacing and the ease of dissolution. Herein, we prepare MnO2-PVP@0.03GO composites by the co-modification of polyvinylpyrrolidone (PVP) pre-insertion layer and graphene oxide (GO) self-assembly layer. The Zn//MnO2-PVP@0.03GO cells deliver a discharge specific capacity of 442 mAh/g at a current density of 0.2 A/g. It also maintains 100% capacity for 1000 times cycling at 1 A/g. The assembled soft package batteries demonstrate superior flexibility and adaptability under different bending conditions.
The escalation in the incidence of multidrug-resistant Gram-negative bacteria is becoming a pressing global concern. Polymyxin B (PMB), a conventional antibiotic with notable therapeutic efficacy against Gram-negative bacterial infections, serves as a crucial final recourse against carbapenem-resistant Klebsiella pneumoniae (CRKP) infections. Nevertheless, the clinical usage of PMB is impeded by its pronounced nephrotoxicity and poor infection site targeting. This investigation is geared to construct a nanoparticle formulation (named HA-PMB@H) comprising hyaluronic acid (HA) and PMB via a simple Schiff base reaction and further coating HA by electrostatic action. HA-PMB@H shows an average size of (153.8 ± 24.3) nm, and a mean zeta potential of (−25.6 ± 5.2) mV. Additionally, PMB can be released from HA-PMB@H more thoroughly and efficiently at pH 5.5 compared to pH 7.4, which demonstrates the Schiff base modification of PMB paves the way for its release at focus of infection. The uptake ratio of HA-PMB@H by alveolar epithelial cells (RLE-6TN) surpassed that of free PMB devoid of HA, which facilitates to the intracellular sterilization of PMB. Furthermore, the employment of HA-PMB@H ameliorated the toxicity of PMB towards human embryonic kidney cells (HEK 293) and pulmonary microvascular endothelial cells (HULEC-5a). What is more, HA-PMB@H effectively managed severe pneumonia induced by CRKP samples from clinical patients diagnosed with CRKP infection in vivo, substantially enhancing the survival rate of mice. Consequently, this nano-delivery system holds promising clinical significance in the combat against drug-resistant bacterial infections.
Developing high performance electrocatalysts for the cathodic oxygen reduction reaction (ORR) is essential for the widespread application of fuel cells. Herein, a promising Pt2NiCo atomic ordered ternary intermetallic compound with N-doped carbon layer coating (o-Pt2NiCo@NC) has been synthesized via a facile method and applied in acidic ORR. The confinement effect provided by the carbon layer not only inhibits the agglomeration and sintering of intermetallic nanoparticles during high temperature process but also provides adequate protection for the nanoparticles, mitigating the aggregation, detachment and poisoning of nanoparticles during the electrochemical process. As a result, the o-Pt2NiCo@NC demonstrates a mass activity (MA) and specific activity (SA) of 0.65 A/mgPt and 1.41 mA/cmPt2 in 0.1 mol/L HClO4, respectively. In addition, after 30,000 potential cycles from 0.6 V to 1.0 V, the MA of o-Pt2NiCo@NC shows much lower decrease than the disordered Pt2NiCo alloy and Pt/C. Even cycling at high potential cycles of 1.5 V for 10,000 cycles, the MA still retains ~70%, demonstrating superior long-term durability. Furthermore, the o-Pt2NiCo@NC also exhibits strong tolerance to CO, SOx, and POx molecules in toxicity tolerance tests. The strategy in this work provides a novel insight for the development of ORR catalysts with high catalytic activity, durability and toxicity tolerance.
Engineering of sulfur vacancies on the basal plane of molybdenum disulfide (MoS2) may provide effective way to promote the catalytic activity. Although the sulfur vacancy density has previously been correlated with catalytic activity, direct evidence that vacancies create surfaces with enhanced electrocatalytic activity is still lacking. Here, we used a combination of scanning electrochemical cell microscopy (SECCM) with submicrometer resolution and photoluminescence imaging to show that sulfur vacancies in monolayer MoS2 microflakes lead to significant spatial heterogeneity in the electrochemical hydrogen evolution reaction (HER) activity. Specifically, colocated multi-microscopy unveils that regions with superior HER activity are associated with sulfur vacancy defects. As the vacancy density increases, the triangular flakes display significantly enhanced and spatially uniformly distributed electrocatalytic activity. Our multi-microscopic imaging approach using SECCM convincingly highlights the spatial heterogeneity of electrocatalytic activity across monolayer MoS2 by sulfur vacancy engineering.
The development of stable and efficient non-noble metal cocatalysts has arisen as a promising yet challenging endeavor in the context of photocatalytic overall water splitting. In this study, NiCo alloy cocatalysts were synthesized with nickel/cobalt metal organic framework (NiCo-MOF) as source of nickel and cobalt. Systematic characterization results demonstrate the successful deposition of alloy cocatalysts onto the surface of SrTiO3. The prepared SrTiO3 loaded NiCo-alloy can generate hydrogen and oxygen in a stoichiometric ratio for photocatalytic overall water splitting, achieving an apparent quantum yield of 11.9% at 350 ± 10 nm. Theoretical calculations indicate that the introduction of cobalt has a beneficial regulatory effect on the hydrogen evolution sites of Ni, reducing the free energy of H adsorption. The synergistic catalytic effect of bimetallic catalysts contributes to enhancing photocatalytic activity and stability. This study offers constructive insights for the development of high-efficiency and cost-effective cocatalyst systems.
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