Resurfacing perovskite nanocrystals (NCs) with tight‐binding and conductive ligands to resolve the dynamic ligands—surface interaction is the fundamental issue for their applications in perovskite ...light‐emitting diodes (PeLEDs). Although various types of surface ligands have been proposed, these ligands either exhibit weak Lewis acid/base interactions or need high polar solvents for dissolution and passivation, resulting in a compromise in the efficiency and stability of PeLEDs. Herein, we report a chemically reactive agent (Iodotrimethylsilane, TMIS) to address the trade‐off among conductivity, solubility and passivation using all‐inorganic CsPbI3 NCs. The liquid TMIS ensures good solubility in non‐polar solvents and reacts with oleate ligands and produces in situ HI for surface etching and passivation, enabling strong‐binding ligands on the NCs surface. We report, as a result, red PeLEDs with an external quantum efficiency (EQE) of ≈23 %, which is 11.2‐fold higher than the control, and is among the highest CsPbI3 PeLEDs. We further demonstrate the universality of this ligand strategy in the pure bromide system (CsPbBr3), and report EQE of ≈20 % at 640, 652, and 664 nm. This represents the first demonstration of a chemically reactive ligand strategy that applies to different systems and works effectively in red PeLEDs spanning emission from pure‐red to deep‐red.
A solution‐phase ligand exchange strategy is used to resurface perovskite nanocrystal surfaces with a chemically active, short and conductive ligand, Iodotrimethylsilane (TMIS), which also functions as a surface passivant. Excellent conductivity and photostability allowed us to fabricate compact, high‐mobility and trap‐free perovskite NC films with high PLQY (>90%). As a result, we achieve CsPbI3 NC‐based PeLEDs with an EQE of ~23%.
Perovskite light‐emitting diodes (LEDs) emitting in the pure‐red range of 630–640 nm show promise in meeting the requirement of the Rec.2100 standard for high‐resolution displays. However, the ...high‐performing LEDs (external quantum efficiency, EQE >20%) in the pure‐red range suffer from half‐life time (luminance drop to 50% of the initial luminance) of <1.6 h, resulting from the injection/transportation barrier and surface‐defects–induced charge carrier quenching. Herein, a bi‐ligand synergy strategy is developed to address the T50 issue: the introduction of iodide‐rich ligands with different chain length increases the vacancy formation energy of halogen ions and enhances the exciton binding energy, resulting in a high photoluminescence quantum yield of over 92%. The treated CsPbBrx/I3−x films exhibit 34‐fold improved material stability related to the control at continuous aging at 100 °C. As a result, pure‐red LEDs with CIE coordinates of (0.698, 0.301) approaching the Rec.2100 standard are reported. These pure‐red LEDs exhibit a low turn‐on voltage of 1.8 V, which is the lowest among reported pure‐red perovskite LEDs, and even 0.15 V lower than the optical bandgap energy (1.95 eV); and a maximum EQE of ≈21% with fourfold enhanced T50 relative to the best previous pure‐red perovskite LEDs.
The iodide‐rich ligands in the bi‐ligand synergy strategy increase the vacancy formation energy of halogen ions, resulting in a high photoluminescence quantum yield of over 92%. The light‐emitting diodes exhibit a maximum external quantum efficiency of ≈21% with fourfold enhanced T50 relative to the best previous pure‐red perovskite light‐emitting diodes.
Recently, the emergence of photoactive metal–organic frameworks (MOFs) has given great prospects for their applications as photocatalytic materials in visible‐light‐driven hydrogen evolution. Herein, ...a highly photoactive visible‐light‐driven material for H2 evolution was prepared by introducing methylthio terephthalate into a MOF lattice via solvent‐assisted ligand‐exchange method. Accordingly, a first methylthio‐functionalized porous MOF decorated with Pt co‐catalyst for efficient photocatalytic H2 evolution was achieved, which exhibited a high quantum yield (8.90 %) at 420 nm by use sacrificial triethanolamine. This hybrid material exhibited perfect H2 production rate as high as 3814.0 μmol g−1 h−1, which even is one order of magnitude higher than that of the state‐of‐the‐art Pt/MOF photocatalyst derived from aminoterephthalate.
The in visible MOF: A high performance for visible‐light‐driven H2‐evolution is obtained with a new methylthio‐functionalized metal–organic framework (MOF) photocatalyst that is rationally designed and facilely prepared. This approach opens up a new way to achieve photocatalysis based on MOF materials with high quantum efficiency value (up to 8.9 %) and excellent photoactivity.
Separation is an important industrial step with critical roles in the chemical, petrochemical, pharmaceutical, and nuclear industries, as well as in many other fields. Although much progress has been ...made, the development of better separation technologies, especially through the discovery of high‐performance separation materials, continues to attract increasing interest due to concerns over factors such as efficiency, health and environmental impacts, and the cost of existing methods. Metal–organic frameworks (MOFs), a rapidly expanding family of crystalline porous materials, have shown great promise to address various separation challenges due to their well‐defined pore size and unprecedented tunability in both composition and pore geometry. In the past decade, extensive research is performed on applications of MOF materials, including separation and capture of many gases and vapors, and liquid‐phase separation involving both liquid mixtures and solutions. MOFs also bring new opportunities in enantioselective separation and are amenable to morphological control such as fabrication of membranes for enhanced separation outcomes. Here, some of the latest progress in the applications of MOFs for several key separation issues, with emphasis on newly synthesized MOF materials and the impact of their compositional and structural features on separation properties, are reviewed and highlighted.
The development of advanced separation materials is central to address challenging separation tasks in a number of essential industrial processes in the petrochemical, pharmaceutical, and nuclear industries. The emerging class of metal–organic frameworks (MOFs) has shown a great promise. The latest advances in MOF materials used for such applications are reviewed.
Abstract
Nationwide prospective surveillance of all-age patients with acute respiratory infections was conducted in China between 2009‒2019. Here we report the etiological and epidemiological ...features of the 231,107 eligible patients enrolled in this analysis. Children <5 years old and school-age children have the highest viral positivity rate (46.9%) and bacterial positivity rate (30.9%). Influenza virus, respiratory syncytial virus and human rhinovirus are the three leading viral pathogens with proportions of 28.5%, 16.8% and 16.7%, and
Streptococcus pneumoniae
,
Mycoplasma pneumoniae
and
Klebsiella pneumoniae
are the three leading bacterial pathogens (29.9%, 18.6% and 15.8%). Negative interactions between viruses and positive interactions between viral and bacterial pathogens are common. A Join-Point analysis reveals the age-specific positivity rate and how this varied for individual pathogens. These data indicate that differential priorities for diagnosis, prevention and control should be highlighted in terms of acute respiratory tract infection patients’ demography, geographic locations and season of illness in China.
Understanding the dynamics and underlying mechanism of carbon exchange between terrestrial ecosystems and the atmosphere is one of the key issues in global change research. In this study, we ...quantified the carbon fluxes in different terrestrial ecosystems in China, and analyzed their spatial variation and environmental drivers based on the long‐term observation data of ChinaFLUX sites and the published data from other flux sites in China. The results indicate that gross ecosystem productivity (GEP), ecosystem respiration (ER), and net ecosystem productivity (NEP) of terrestrial ecosystems in China showed a significantly latitudinal pattern, declining linearly with the increase of latitude. However, GEP, ER, and NEP did not present a clear longitudinal pattern. The carbon sink functional areas of terrestrial ecosystems in China were mainly located in the subtropical and temperate forests, coastal wetlands in eastern China, the temperate meadow steppe in the northeast China, and the alpine meadow in eastern edge of Qinghai‐Tibetan Plateau. The forest ecosystems had stronger carbon sink than grassland ecosystems. The spatial patterns of GEP and ER in China were mainly determined by mean annual precipitation (MAP) and mean annual temperature (MAT), whereas the spatial variation in NEP was largely explained by MAT. The combined effects of MAT and MAP explained 79%, 62%, and 66% of the spatial variations in GEP, ER, and NEP, respectively. The GEP, ER, and NEP in different ecosystems in China exhibited ‘positive coupling correlation’ in their spatial patterns. Both ER and NEP were significantly correlated with GEP, with 68% of the per‐unit GEP contributed to ER and 29% to NEP. MAT and MAP affected the spatial patterns of ER and NEP mainly by their direct effects on the spatial pattern of GEP.
National-based prospective surveillance of all-age patients with acute diarrhea was conducted in China between 2009‒2018. Here we report the etiological, epidemiological, and clinical features of the ...152,792 eligible patients enrolled in this analysis. Rotavirus A and norovirus are the two leading viral pathogens detected in the patients, followed by adenovirus and astrovirus. Diarrheagenic Escherichia coli and nontyphoidal Salmonella are the two leading bacterial pathogens, followed by Shigella and Vibrio parahaemolyticus. Patients aged <5 years had higher overall positive rate of viral pathogens, while bacterial pathogens were more common in patients aged 18‒45 years. A joinpoint analysis revealed the age-specific positivity rate and how this varied for individual pathogens. Our findings fill crucial gaps of how the distributions of enteropathogens change across China in patients with diarrhea. This allows enhanced identification of the predominant diarrheal pathogen candidates for diagnosis in clinical practice and more targeted application of prevention and control measures.
Lithium reactivity with electrolytes leads to their continuous consumption and dendrite growth, which constitute major obstacles to harnessing the tremendous energy of lithium-metal anode in a ...reversible manner. Considerable attention has been focused on inhibiting dendrite via interface and electrolyte engineering, while admitting electrolyte-lithium metal reactivity as a thermodynamic inevitability. Here, we report the effective suppression of such reactivity through a nano-porous separator. Calculation assisted by diversified characterizations reveals that the separator partially desolvates Li
in confinement created by its uniform nanopores, and deactivates solvents for electrochemical reduction before Li
-deposition occurs. The consequence of such deactivation is realizing dendrite-free lithium-metal electrode, which even retaining its metallic lustre after long-term cycling in both Li-symmetric cell and high-voltage Li-metal battery with LiNi
Mn
Co
O
as cathode. The discovery that a nano-structured separator alters both bulk and interfacial behaviors of electrolytes points us toward a new direction to harness lithium-metal as the most promising anode.
The role of cancer cell FOXP3 in tumorigenesis is conflicting. We aimed to study FOXP3 expression and regulation, function and clinical implication in human non-small cell lung cancer (NSCLC).
One ...hundred and six patients with histologically-confirmed NSCLC who underwent surgery were recruited for the study. Tumor samples and NSCLC cell lines were used to examine FOXP3 and its related molecules. Various cell functions related to tumorigenesis were performed. In vivo mouse tumor xenograft was used to confirm the in vitro results.
NSCLC patients with the high level of FOXP3 had a significant decrease in overall survival and recurrence-free survival. FOXP3 overexpression significantly induced cell proliferation, migration, and invasion, whereas its inhibition impaired its oncogenic function. In vivo studies confirmed that FOXP3 promoted tumor growth and metastasis. The ectopic expression of FOXP3 induced epithelial-mesenchymal transition (EMT) with downregulation of E-cadherin and upregulation of N-cadherin, vimentin, snail, slug, and MMP9. The oncogenic effects by FOXP3 could be attributed to FOX3-mediated activation of Wnt/β-catenin signaling, as FOXP3 increased luciferase activity of Topflash reporter and upregulated Wnt signaling target genes including c-Myc and Cyclin D1 in NSCLC cells. Co-immunoprecipitation results further indicated that FOXP3 could physically interacted with β-catenin and TCF4 to enhance the functions of β-catenin and TCF4, inducing transcription of Wnt target genes to promote cell proliferation, invasion and EMT induction.
FOXP3 can act as a co-activator to facilitate the Wnt-b-catenin signaling pathway, inducing EMT and tumor growth and metastasis in NSCLC.
Polymer electrolyte membrane water electrolysis (PEMWE) has been regarded as a promising technology for renewable hydrogen production. However, acidic oxygen evolution reaction (OER) catalysts with ...long‐term stability impose a grand challenge in its large‐scale industrialization. In this review, critical factors that may lead to catalyst's instability in couple with potential solutions are comprehensively discussed, including mechanical peeling, substrate corrosion, active‐site over‐oxidation/dissolution, reconstruction, oxide crystal structure collapse through the lattice oxygen‐participated reaction pathway, etc. Last but not least, personal prospects are provided in terms of rigorous stability evaluation criteria, in situ/operando characterizations, economic feasibility and practical electrolyzer consideration, highlighting the ternary relationship of structure evolution, industrial‐relevant activity and stability to serve as a roadmap towards the ultimate application of PEMWE.
The large‐scale application of polymer electrolyte membrane water electrolysis (PEMWE) is suffering from long‐term stability challenges in anodic oxygen evolution reaction (OER). This review provides a thorough discussion of degradation mechanisms, catalyst design principles and future research opportunities to serve as a cornerstone for overcoming the dilemma in acidic OER stability and achieving the industrialization of water electrolysis.
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