In this work, two novel thermally activated delayed fluorescence (TADF) emitters, 2tDMG and 3tDMG, are synthesized for high‐efficiency organic light‐emitting diodes (OLEDs), The two emitters have a ...tilted face‐to‐face alignment of donor (D)/acceptor (A) units presenting intramolecular noncovalent interactions. The two TADF materials are deposited either by an evaporation‐process or by a solution‐process, both of them leading to high OLED performance. 2tDMG used as the emitter in evaporation‐processed OLEDs achieves a high external quantum efficiency (EQE) of 30.8% with a very flat efficiency roll‐off of 7% at 1000 cd m−2. The solution‐processed OLEDs also display an interesting EQE of 16.2%. 3tDMG shows improved solubility and solution processability as compared to 2tDMG, and thus a high EQE of 20.2% in solution‐processed OLEDs is recorded. The corresponding evaporation‐processed OLEDs also reach a reasonably high EQE of 26.3%. Encouragingly, this work provides a novel strategy to address the imperious demands for OLEDs with high EQE and low roll‐off.
A thermally activated delayed fluorescence emitter, 2tDMG, is designed and synthesized based on the donor (D)/acceptor (A) spatially intramolecular noncovalent interaction. The D/A units are connected via a rigid linker, thereby confining them into a close‐packed coplanar configuration for small singlet–triplet splitting energy. 2tDMG achieves a high external quantum efficiency of 30.8% with a low efficiency roll‐off in evaporation‐processed organic light‐emitting diodes (OLEDs).
Near‐infrared (NIR) organic solid‐state lasers play an essential role in applications ranging from laser communication to infrared night vision, but progress in this area is restricted by the lack of ...effective excited‐state gain processes. Herein, we originally proposed and demonstrated the cascaded occurrence of excited‐state intramolecular proton transfer for constructing the completely new energy‐level systems. Cascading by the first ultrafast proton transfer of <430 fs and the subsequent irreversible second proton transfer of ca. 1.6 ps, the stepwise proton transfer process favors the true six‐level photophysical cycle, which supports efficient population inversion and thus NIR single‐mode lasing at 854 nm. This work realizes longest wavelength beyond 850 nm of organic single‐crystal lasing to date and originally exploits the cascaded excited‐state molecular proton transfer energy‐level systems for organic solid‐state lasers.
Six‐level energy systems are constructed through the cascaded occurrence of excited‐state intramolecular proton transfer consisting of a first ultrafast proton transfer of <430 fs and a following dominant and irreversible proton transfer of ca. 1.6 ps, which support the NIR single‐mode lasing at 854 nm for exploiting energy‐level systems of OSSLs, especially at the NIR region from 780 to 2500 nm.
Although highly useful in supramolecular chemistry, pillararenes lack a fluorophore in their skeleton. Here we present BowtieArene, a novel fluorescent dual macrocycle, featuring a central ...tetraphenylethylene‐derived fluorophore and two pillar‐like, pentagon‐shaped cavities which are comparable to pillar5arene. This concisely prepared, figure‐of‐eight molecule exhibits vapor absorption and host–guest capabilities, as well as intriguing switchable fluorescence. The fluorochromism of BowtieArene can be triggered by multiple external stimuli including solvent, vapor, and mechanical force, with excellent reversibility and stability. Experimental and theoretical evidence indicate that the fluorochromism should be closely related to molecular packing.
Colorful bowtie: The novel fluorescent dual macrocycle BowtieArene features a central tetraphenylethylene‐derived fluorophore, double pillar‐like cavities, and solvent‐, vapor‐, and mechano‐induced fluorochromism. The switchable fluorescence is closely related to changes in the molecular packing mode.
Motivated by the concept of energy-optimized air/space vehicles, the design of more-electric and all-electric vehicles has become increasingly popular. With the advance of micro-electro-mechanical ...systems, on-board electronic/electrical devices become more integrated and miniaturized. It means that these highly-advanced devices should rely on a high heat-flux dissipation method to maintain an effective and safe operation. Spray cooling, universally recognized as the next-generation cooling scheme, has been extensively utilized in the thermal protection of the ground-based electric/electronic equipment. In contrast, the aerospace-oriented spray cooling (AOSC) application is extremely rare. It can be attributed to the fact that the research into the space/air-oriented spray cooling technologies is still in its infancy, which leads to a lack in the knowledge of alternations of flow patterns and heat transfer behaviors caused by the complicated space or high-altitude space. This paper presents a comprehensive review of the up-to-date published articles on AOSC and divides these published articles into four categories: 1) investigation into the effect of gravity on the cooling performance; 2) investigation into the effect of environmental pressure on the cooling performance; 3) study of the effect of acceleration and vibration on the cooling performance; 4) investigation of the aerospace spray cooling system. Additionally, comments, perspectives, and orientations are provided, in which several promising contributions are highlighted. This paper aims to promote the practical application of the AOSC system which could facilitate the development of the energy-optimized green air/space vehicle.
•A review of aerospace-oriented spray cooling technology is performed.•Gravity plays a significant role in the flow pattern and heat & mass transfer.•A heat transfer enhancement can be gained by flash Boiling/evaporation.•Gravity-immune spray cooling systems promote its practical aerospace application.•Affordable ground-based research method for aerospace application is imperative.
Algae-bacteria consortia treatment has been found to be a promising method for the remediation of aqueous systems. Given the scope of previous reviews on algae-bacteria interactions, the sections on ...chemical signaling between algae and bacteria don't cover the current knowledge gap, and recent advances of algae-bacteria consortia in aqueous remediation don't explore the full depth. Accordingly, the specific aim of this review was to thoroughly screen and summarize recent peer-reviewed literature on (1) the mechanism of algal selection and enrichment in wastewater treatment; (2) interactions between algae and bacteria in ecological niche environments; (3) chemical signaling between algae and bacteria; (4) aqueous remediation using the algae-bacteria consortia; and (5) advanced treatment techniques combined with algae-bacteria systems for improved aqueous remediation. The main current challenges and future perspectives in algae-bacteria consortia wastewater treatment are proposed, including: (i) comprehensively establishing the network of interactions between algae and bacteria, especially quorum sensing and phycospheric interactions; (ii) developing a detailed understanding of the chemical exchange between microbial species based on molecular diffusion processes; (iii) tracking complex algae-bacteria interactions in aquatic environments using machine learning (ML), providing a potential tool for the design of beneficial and customizable synthetic microbial communities for wastewater treatment; (iv) integrating advanced treatment techniques (e.g., MBRs, UV photolysis and biological activated carbon) with algae-bacteria consortia systems, increasing the sustainability and applicability of treatment processes. Therefore, this review provides guidance and insights on the future development of algae-bacteria consortia treatment systems and their potential application for aqueous remediation.
Adipocytes arising from mesenchymal stem cells (MSCs) requires MSC adipocyte commitment and differentiation of preadipocytes to mature adipocytes. Several signaling and some cytokines affect the ...adipogenesis of MSCs. This review focuses on the roles of TGF-β/SMAD signaling in adipocyte commitment of MSCs. BMP4 and BMP7 signaling are sufficient to induce adipocyte lineage determination of MSCs. The roles of BMP2, TGF-β, and myostatin signaling in this process are unclear. Other TGF-β/SMAD signaling such as BMP3 and BMP6 signaling have almost no effect on commitment because of limited research available, while GDF11 signaling inhibits adipocyte commitment in human MSCs. In this review, we summarize the available information on TGF-β/SMAD signaling regulation of MSCs in adipocyte commitment. Deeper study of this commitment mechanism will offer new approaches in treating obesity, diabetes mellitus, and obesity-related metabolism syndrome.
Voltage-gated ion channels are integral membrane proteins that respond to changes in membrane potential with rapid variations in membrane permeability to ions ....
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%.
The development of electrocatalysts capable of efficient reduction of nitrate (NO
) to ammonia (NH
) is drawing increasing interest for the sake of low carbon emission and environmental protection. ...Herein, we present a CuCo bimetallic catalyst able to imitate the bifunctional nature of copper-type nitrite reductase, which could easily remove NO
via the collaboration of two active centers. Indeed, Co acts as an electron/proton donating center, while Cu facilitates NO
adsorption/association. The bio-inspired CuCo nanosheet electrocatalyst delivers a 100 ± 1% Faradaic efficiency at an ampere-level current density of 1035 mA cm
at -0.2 V vs. Reversible Hydrogen Electrode. The NH
production rate reaches a high activity of 4.8 mmol cm
h
(960 mmol g
h
). A mechanistic study, using electrochemical in situ Fourier transform infrared spectroscopy and shell-isolated nanoparticle enhanced Raman spectroscopy, reveals a strong synergy between Cu and Co, with Co sites promoting the hydrogenation of NO
to NH
via adsorbed *H species. The well-modulated coverage of adsorbed *H and *NO
led simultaneously to high NH
selectivity and yield.
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.
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