Outstanding Maximum Research Articles

Three‐Dimensional VTe2/MXene/CNT Ternary Architectures for the Development of High Performance Microsupercapacitors

AbstractRapid advancements in portable electronics have created a demand for ultrathin power sources. Microsupercapacitors (MSCs) are becoming a competitive and advantageous option for these applications. It is widely recognized that to develop MSCs with exceptional performance, electrode materials having two‐dimensonal (2D) permeable channels, structural scaffolds with high‐conductivity and large surface area are suitable. Vanadium ditelluride (VTe2) stands out as an ideal material platform in this context. Its unique combination of metallic properties and exfoliative characteristics‐stemming from the conducting Te–V–Te layers held together by weak van der Waals interlayer interactions‐ renders it highly promising for high‐performance MSCs. This study is the first to report that the restacking issues and electrochemical performance of VTe2 can be successfully avoided by the simultaneous incorporation of MXene and CNT to form a ternary hybrid. Here, a laser‐induced graphene (LIG)‐based MSC utilizing VTe2/MXene/CNT as the active electrode material is fabricated. This MSC achieve fabrications an outstanding maximum energy density of 6.84 µWh cm−2 and a power density of 304.7 µW cm−2. This significant achievement demonstrates the potential of this LIG‐based MSC to advance the design of high‐performance micro‐energy storage devices.

Enhanced energy storage efficiency of an innovative three-dimensional nickel cobalt metal organic framework nanocubes with molybdenum disulphide electrode material as a battery-like supercapacitor

Recently, metal-organic frameworks (MOFs) with transition metal sulfides have gained much attention as electrode materials for supercapacitors (SCs). In this work, 3D-NCMOF@MS NCs, incorporating two-dimensional molybdenum disulphide (2D-MS) nanosheets and three-dimensional nickel cobalt-MOF nanocubes (3D-NCMOF NCs) are synthesized by a solvothermal and precipitation process. Owing to their enhanced electrical conductivity and huge surface area, the 3D-NCMOF@MS NCs produce superior electrochemical responses in SCs compared to 2D-MS and 3D-NCMOF NCs. The results demonstrate that the synergistic 3D-NCMOF@MS NCs increased specific capacitance up to 1048 Fg−1 at 1 Ag−1, revealing outstanding cycle stability with a capacitance retention of 99.06 %. Besides, the exposed high-power density of 3D-NCMOF@MS NCs reached 400 W kg−1 as well as an outstanding maximum energy density of 188.64 Wh kg−1. Such synergistic effects of the multivalent states of Ni, Co, and Mo promote electrochemical characteristics, implying that the 3D-NCMOF@MS NCs could potentially be used in energy storage systems, boosting electrochemical performance.

Designing nano-heterostructured nickel doped tin sulfide/tin oxide as binder free electrode material for supercapattery

New generation of electrochemical energy storage devices (EESD) such as supercapattery is being intensively studied as it merges the ideal energy density of batteries and optimal power density of supercapacitors in a single device. A multitude of parameters such as the method of electrodes preparation can affect the performance of supercapattery. In this research, nickel doped tin sulfide /tin oxide (SnS@Ni/SnO2) heterostructures were grown directly on the Ni foam and subjected to different calcination temperatures to study their effect on formation, properties, and electrochemical performance through X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and electrochemical tests. The optimized SnS@Ni/SnO2 electrode achieved a maximum specific capacity of 319 C g− 1 while activated carbon based capacitive electrode exhibited maximum specific capacitance of 381.19 Fg− 1. Besides, capacitive electrodes for the supercapattery were optimized by incorporating different conductive materials such as acetylene black (AB), carbon nanotubes (CNT) and graphene (GR). Assembling these optimized electrodes with the aid of charge balancing equation, the assembled supercapattery was able to achieve outstanding maximum energy density and power density of 36.04 Wh kg− 1 and 12.48 kW kg− 1 with capacity retention of 91% over 4,000 charge/discharge cycles.

Refractive index sensing characteristics of PCF-SPR based on dual-plasmon materials

Abstract In this paper, a photonic crystal fiber (PCF) refractive index sensor based on surface plasmon resonance (SPR) with dual plasmonic materials (indium tin oxide and gold) is proposed. We innovatively designed a dual-core PCF structure and pore arrangement effectively enhancing the coupling effect. Using two different plasma materials, phase matching is achieved at two different wavelengths for the evanescent and surface plasmon waves, resulting in dual resonance peaks. The refractive index sensing is accomplished by measuring the dual-peak resonance shift, which expands the detection wavelength and RI detection ranges. The sensor can detect analytes with refractive indices ranging from 1.32 to 1.43 at wavelengths between 0.4 um and 1.4 um. We optimized the photonic crystal fiber structure and studied the sensing performance of the sensor, improving its sensitivity. Simulation results indicate that the designed PCF sensor exhibits outstanding maximum dual-peak shift sensitivity (DPSS), reaching up to 28,000 RIU-1, along with maximum amplitude sensitivity (AS) and wavelength sensitivity (WS) of 18,500 RIU-1 and 34,500 RIU-1, respectively, in the direction of y-polarization. Furthermore, the sensor achieves high resolution, and the figure of merit (FOM) values can reach up to 5.134×10-7 and 2758. Consequently, the proposed sensor can provide high-precision and extensive-range measurements of solution refractive indices within the visible and infrared light spectrum, and it holds potential application prospects in numerous fields, such as food safety testing and chemical substance detection.

Fabrication of Hierarchically Porous “Fish Cage”‐like Carbonaceous Nanomaterials via Soft Template‐assisted Strategy for Cr Removal: Accelerated Stepped Adsorption and Enhanced Coordination Effect

The negative impact of heavy metal pollution, specifically chromium (VI), on human health is well‐documented. To solve this issue, hollow anisotropic hierarchically porous “Fish Cage”‐like carbonaceous nanomaterial (N,S‐HFC‐180) with multi‐active groups is synthesized. Hierarchically porous structure provides stepped adsorption effect. The addition of K2C2O4 leads to the specific surface area of N,S‐HFC‐180 increases to 1914.21 m2·g‐1 (an increase of ~552 times compared to HFC‐180). Thiourea introduces multi‐active groups act as “Barbs” in “Fish Cage” further reducing Cr(VI) to Cr(III) and sequestrating Cr(III) by coordination effect. Subsequent batch studies suggest that N,S‐HFC‐180 exhibits a high removal capacity of 164.29 mg·g‐1 for Cr(VI) at pH = 2. The kinetics and isotherm analyses display an outstanding maximum adsorption capacity of 393.88 mg·g‐1 at 298 K. In addition, even after seven cycles, the removal rate of Cr(VI) using N,S‐HFC‐180 remains > 85.00%, and it effectively reduces the concentration of electroplating wastewater from 55.82 to 0.14 mg·L‐1. Pore filling, chemical reduction and chelation, hydrogen bond and electrostatic attraction are the primary adsorption drivers. The results suggest that, the recoverable N,S‐HFC‐180 highlights its viability for practical applications in wastewater treatment processes.

Decoding the Impact of Molecular Configuration on High‐Efficiency Blue Hot Exciton Emitters

AbstractRealizing highly efficient organic light‐emitting diodes (OLEDs) based on “hot exciton” emitters is crucial for the widespread use of purely organic electroluminescence. Herein, it is demonstrated that the radiative decay rate, modulated by molecular configuration, plays a vital role in determining the optoelectronic properties of hot exciton materials. The proof‐of‐concept isomers, TPA‐1IPCN and TPA‐3IPCN, and TPA‐1IANCN and TPA‐3IANCN are intentionally designed and successfully synthesized. By employing a novel donor–acceptor–acceptor (D–A'–A) molecular architecture, implementing a molecular isomerization strategy, incorporating diverse steric hindrance moieties, and strategically manipulating the positioning of functional groups, precise modulation of the molecular configuration can be achieved to enable accurate regulation of the radiative decay rate. Consequently, various optoelectronic properties, including photoluminescent wavelength, photoluminescence quantum yield, fluorescence lifetime, packing mode in aggregated state, and molecular horizontal dipole ratios in films, undergo significant modifications. As a result, non‐doped blue OLED based on TPA‐1IPCN exhibits outstanding maximum external quantum efficiency (EQE) of 10.3% with minimal efficiency roll‐off—one of the highest reported values for blue OLEDs based on hot exciton materials.

Manipulating the photophysical properties of multi-donor molecules for fast reverse intersystem crossing in solution-processed OLED devices

The slow reverse intersystem crossing (RISC) rate in thermally activated delayed fluorescence (TADF) emitters result in extended exciton lifetime and pronounced efficiency loss at high luminance level. To address this limitation, we have developed and characterized a series of novel compounds featuring triazine cores substituted with tert-butyl carbazole moieties at various positions and quantities. The objective here is to fine-tune the charge transfer properties, thereby enhancing the efficiency of the RISC process. Our studies reveal that through-space charge transfer is more effective than long-range through-bond charge transfer in minimizing the singlet-triplet energy gap and accelerating RISC. The optimized compound, 4tCzTrz, exhibits an exceptionally fast RISC rate of 1.02 × 107 s−1 and a high photoluminescence quantum yield of up to 100 %. Solution-processed organic light-emitting diodes (OLEDs) incorporating this molecule have achieved outstanding maximum external quantum efficiencies of around 20 %, whether used as an emitter directly or as a sensitizer to boost overall emission efficiency.

Fabrication and electrochemical performance of Ni[sbnd]Cu carbonate/hydroxide-based electrodes for high-performance supercapacitors

The increasing usage of high-performance equipment necessitates the exploration of new energy storage solutions. Supercapacitors offer significant advantages over secondary batteries, including longer lifespan, faster charge/discharge rates, higher power density, and greater reliability. Three-dimensional porous NiCu(CO3)(OH)2 nanowires were directly synthesized on Ni foam using a binder-free hydrothermal method as positive electrodes in high-performance supercapacitors. The unique nanowire structure of NiCu(CO3)(OH)2 plays a pivotal role in enhancing electrical performance by providing substantial surface area, improving electrode/electrolyte contact, and shortening ion diffusion paths. The use of Ni- and Cu-based binary transition metal electrodes contributes to high specific capacitance, rapid charge-discharge rates, and excellent cycling stability, collectively resulting in the development of high-capacity supercapacitors. Furthermore, density functional theory calculations were employed to elucidate the electrode formation energy based on the Ni/Cu ratio, assessing the structural stability of electrodes and offering insights for future energy storage device development. The optimized NiCu(CO3)(OH)2 nanowire compound exhibited an outstanding maximum specific capacity of 211.1 mAh g−1 at 3 A g−1. Furthermore, an asymmetric supercapacitor was constructed using the NiCu(CO3)(OH)2 composite as the positive electrode and graphene as the negative electrode. The resulting asymmetric supercapacitors demonstrate a remarkable energy density of 26.7 W h kg−1 at a power density of 2534 W kg−1, along with exceptional cycling stability, retaining 91.3% of its capacity after 5000 cycles. Consequently, the asymmetric supercapacitors incorporating NiCu(CO3)(OH)2 exhibit superior electrical properties compared to most previously reported Ni- and Cu-based asymmetric supercapacitors.

Anti-Oxidized Self-Assembly of Multilayered F-Mene/MXene/TPU Composite with Improved Environmental Stability and Pressure Sensing Performances.

MXenes, as emerging 2D sensing materials for next-generation electronics, have attracted tremendous attention owing to their extraordinary electrical conductivity, mechanical strength, and flexibility. However, challenges remain due to the weak stability in the oxygen environment and nonnegligible aggregation of layered MXenes, which severely affect the durability and sensing performances of the corresponding MXene-based pressure sensors, respectively. Here, in this work, we propose an easy-to-fabricate self-assembly strategy to prepare multilayered MXene composite films, where the first layer MXene is hydrogen-bond self-assembled on the electrospun thermoplastic urethane (TPU) fibers surface and the anti-oxidized functionalized-MXene (f-MXene) is subsequently adhered on the MXene layer by spontaneous electrostatic attraction. Remarkably, the f-MXene surface is functionalized with silanization reagents to form a hydrophobic protective layer, thus preventing the oxidation of the MXene-based pressure sensor during service. Simultaneously, the electrostatic self-assembled MXene and f-MXene successfully avoid the invalid stacking of MXene, leading to an improved pressure sensitivity. Moreover, the adopted electrospinning method can facilitate cyclic self-assembly and the formation of a hierarchical micro-nano porous structure of the multilayered f-MXene/MXene/TPU (M-fM2T) composite. The gradient pores can generate changes in the conductive pathways within a wide loading range, broadening the pressure detection range of the as-proposed multilayered f-MXene/MXene/TPU piezoresistive sensor (M-fM2TPS). Experimentally, these novel features endow our M-fM2TPS with an outstanding maximum sensitivity of 40.31 kPa-1 and an extensive sensing range of up to 120 kPa. Additionally, our M-fM2TPS exhibits excellent anti-oxidized properties for environmental stability and mechanical reliability for long-term use, which shows only ~0.8% fractional resistance changes after being placed in a natural environment for over 30 days and provides a reproducible loading-unloading pressure measurement for more than 1000 cycles. As a proof of concept, the M-fM2TPS is deployed to monitor human movements and radial artery pulse. Our anti-oxidized self-assembly strategy of multilayered MXene is expected to guide the future investigation of MXene-based advanced sensors with commercial values.

Urchin-like CO2-responsive magnetic microspheres for highly efficient organic dye removal

CO2-responsive materials have emerged as promising adsorbents for the remediation of refractory organic dyes-contaminated wastewater without the formation of byproducts or causing secondary pollution. However, realizing the simultaneous adsorption−separation or complete removal of both anionic and cationic dyes, as well as achieving deeper insights into their adsorption mechanism, still remains a challenge for most reported CO2-responsive materials. Herein, a novel type of urchin-like CO2-responsive Fe3O4 microspheres (U-Fe3O4 @P) has been successfully fabricated to enable ultrafast, selective, and reversible adsorption of anionic dyes by utilizing CO2 as a triggering gas. Meanwhile, the CO2-responsive U-Fe3O4 @P microspheres exhibit the capability to initiate Fenton degradation of non-adsorbable cationic dyes. Our findings reveal exceptionally rapid adsorption equilibrium, achieved within a mere 5 min, and an outstanding maximum adsorption capacity of 561.2 mg g−1 for anionic dye methyl orange upon CO2 stimulation. Moreover, 99.8% of cationic dye methylene blue can be effectively degraded through the Fenton reaction. Furthermore, the long-term unresolved interaction mechanism of organic dyes with CO2-responsive materials is deciphered through a comprehensive experimental and theoretical study by density functional theory. This work provides a novel paradigm and guidance for designing next-generation eco-friendly CO2-responsive materials for highly efficient purification of complex dye-contaminated wastewater in environmental engineering.

Highly Efficient Copper(I) Emitters Supported by Secondary Metal‐Ligand Interactions

AbstractThe most prominent way of tuning optoelectronic properties of copper(I) emitters is primary‐sphere ligand engineering, but little attention is placed on noncovalent interactions. Here, an effective strategy is demonstrated to introduce secondary metal‐ligand interactions into two‐coordinate Cu(I) emitters with the goals of optimizing conformations and improving optical properties. As a proof of concept, a panel of Cu(I) complexes is developed via chalcogen‐heterocyclic engineering on the 1,2‐positions of carbazole ligand. The S‐embedded complexes have distinct noncovalent metal‐ligand interactions originating from S···Cu orbital contacts, verified by single‐crystal structure and theoretical simulation. Thanks to the flattened conformations stabilized by secondary metal‐ligand interactions, the optimized Cu(I) emitters afford high emission quantum yields of up to 93% and short radiative lifetimes of down to 0.8 µs. Cu‐12BT and Cu‐12BF support the resultant organic light‐emitting diodes (OLEDs) delivering outstanding maximum external quantum efficiencies (EQEs) of 24.3% and 28.6%, respectively, among the best performance for Cu(I) emitters. The optimal devices based on Cu‐12BF also achieve 18.7% EQE at the practical luminance of 100 nits. This work unlocks the large potential of noncovalent interactions in developing excellent Cu(I) emitters for cost‐effective and high‐efficiency OLEDs.

Boosted electrostatic interaction by surface sulfonation over Calixarene-TPE copolymer for prompt adsorption of cationic contaminates

Removal of cationic pollutants, including dyes, herbicides, and antibiotics from water is significant owing to their persistence, bioaccumulation, carcinogenicity, mutagenicity, and reproductive risks. In this paper, a calixarene-tetraphenyl ethylene containing copolymer adsorbent, named CP-TPE, was synthesized using the Suzuki-Miyaura coupling reaction between the resorcinol calixarene and tetraphenyl ethylene boric acid esters. Subsequently, the phenolic groups on the CP-TPE were further reacted with chlorosulfonic acid, resulting in a sulfonated product named CP-TPE-SO3H. The introduction of the sulfonate groups not only significantly improved the hydrophilicity of CP-TPE-SO3H but also enhanced the electrostatic interaction between CP-TPE-SO3H and cationic molecules, achieving an outstanding maximum adsorption capacity for paraquat (representative herbicide, 300.06 mg g−1) and tetracycline hydrochloride (representative antibiotic, 888.74 mg g−1), which surpassed the majority of reported polymeric adsorbents. Moreover, the k2 of CP-TPE-SO3H on TC (0.0407 g mg−1 min−1) reached the maximum value reported so far. This study demonstrated the significance and superiority of sulfonation modification in synthesizing POPs-based adsorbents, which can be potentially employed in real wastewater treatment.

Unlocking the luminescent potential of Pr3+/Yb3+ Co-doped Y2Mo4O15 for advanced thermometry applications

In this study, Pr3+/Yb3+ co-doped Y2Mo4O15 phosphor was successfully synthesized using the traditional citric acid-assisted sol-gel method, with the aim of exploring its potential for optical thermometry applications. The structural and morphological characteristics of the synthesized sample were comprehensively analyzed through X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). Photoluminescence and temperature-dependent luminescence properties were systematically investigated within a temperature range of 298 K to 508 K, employing 473 nm excitation. To assess the temperature sensing capabilities of the phosphors, we utilized both the fluorescence intensity ratio (FIR) and fluorescence lifetime (FL) techniques. Optical temperature measurements were conducted through both thermal and non-thermal coupling methods. Our findings revealed that the FIR (I547/I490) exhibited an outstanding maximum sensitivity of 1.27% K−1, accompanied by remarkably low-temperature uncertainty (δT) values ranging from 0.04 to 0.83 K. This outstanding performance makes it the optimal choice for temperature sensing. Additionally, when employing FL thermometry, the maximum sensitivity (Sr) was determined to be 0.21% K−1 at 538 K. These results strongly indicate the significant potential of Y2Mo4O15: Pr3+/Yb3+ in the realm of optical thermometry, offering promising opportunities for precise and reliable temperature measurements.

Hydrogen-Bonded Organic Framework Derived 2D N, O Co-Doped Carbon Nanobelt with Tunable Pseudocapacitive Contribution for Efficient Capacitive Deionization.

Defect engineering is recognized as an attractive method for modulating the electronic structure and physicochemical characteristics of carbon materials. Exploiting heteroatom-doped porous carbon with copious active sites has attracted great attention for capacitive deionization (CDI). However, traditional methods often rely on the utilization of additional heteroatom sources and strong corrosive activators, suffering from low doping efficiency, insufficient doping level, and potential biotoxicity. Herein, hydrogen-bonded organic frameworks (HOFs) are employed as precursors to synthesize N, O co-doped porous carbon via a simple and green reverse defect engineering strategy, achieving controllable heavy doping of heteroatoms. The N, O co-doping triggers significant pseudocapacitive contribution and the surface pore structure supports the formation of the electric double layer. Therefore, when HOF-derived N, O co-doped carbon is used as CDI electrodes, a superior salt adsorption capacity of 32.29±1.42mgg-1 and an outstanding maximum salt adsorption rate of 10.58±0.46mgg-1min-1 at 1.6V in 500mgL-1 NaCl solution are achieved, which are comparable to those of state-of-the-art carbonaceous electrodes. This work exemplifies the effectiveness of the reverse nitrogen-heavy doping strategy on improving the carbon structure, shedding light on the further development of rational designed electrode materials for CDI.

Design and performance assessment of novel Fe3O4 decorated nanoblend of guar gum/graphene oxide flakes and CuO for mitigation of fluoroquinolones from wastewater

Organic-inorganic nanoblends particularly, polysaccharide-blended-inorganic ones, possess interesting properties and hence versatile applications, due to which they have become the focus of much research attention, lately. The present study reports the fabrication of magnetic guar gum/graphene oxide nanocomposite blended with CuO to obtain a novel nanoblend, mGG/GO/CuO NB, through a two-stepped synthesis route: preparation of GO via Improved Hummers technique followed by mGG/GO/CuO NB preparation using co-precipitation method. The nanocomposite was subsequently investigated for its capacity for adsorptive elimination of ciprofloxacin from aqueous medium. It was identified using typical physico-chemical techniques, such as XRD, Raman, and FTIR spectroscopy; EDX and FESEM for morphological investigation; as well as VSM, pHZPC and TGA. The Langmuir isotherm model and the pseudo second order model are obtained as the isotherm model and kinetic model that can best depict the adsorption behaviour. The Langmuir isotherm model provided an outstanding maximum adsorption capacity value of 769.23 mg g−1 for CPX removal. Thermodynamics studies witness a spontaneous adsorption with an exergonic behaviour supported by a ΔGo value of −11.74 kJ mol−1 and ΔHo value of −49.976 kJ mol−1 as well as an increase in ΔSo value (+189.32 mol−1). Columbic/electrostatic interactions, hydrophobic interactions, hydrogen bonds, and electron-donor-acceptor (EDA) interactions are the main interacting forces predicted to be pivotal in the adsorption mechanism.

Safe and stable Li–CO2 battery with metal-organic framework derived cathode composite and solid electrolyte

Li–CO2 batteries receive wide attention due to their strategic utilization of CO2 and high energy density. However, their practical application is hindered by sluggish kinetics and safety hazards. Herein, a stable and highly conductive ceramic-based solid electrolyte (Li1.4Al0.4Ti1.6(PO4)3) is used to enhance the safety aspect. In contrast, a metal-organic framework (MOF) based catalyst is introduced to ensure low polarization and long cycle life for Li–CO2 batteries. The as-prepared Li–CO2 cell delivers an outstanding maximum specific capacity of 6698 mA h g−1 at 100 mA g−1 current density. Besides, the cell shows a stable performance over 100 cycles of charge-discharge with a cut-off capacity of 500 mA h g−1. Later, the post-cycling analysis is performed to evaluate the electrode degradation mechanism. Further, to understand the interactions between the Co3O4-based catalyst and carbon-based host electrode with discharge product, we perform first-principles calculations based on density functional theory. This work shows great potential for the use of MOF cathode catalyst in Li–CO2 battery and is believed to be particularly promising for a stable operation.

Outstanding adsorption capacity of iron oxide synthesized with extract of açaí berry residue: kinetic, isotherm, and thermodynamic study for dye removal.

Contamination of water by toxic dyes is a serious environmental problem. Adsorbents prepared by an environmentally safe route have stood out for application in pollutant removal. Herein, iron oxide-based nanomaterial composed of Fe(III)-OOH and Fe(II/III) bound to proanthocyanidins, with particles in the order of 20 nm, was prepared by green synthesis assisted by extract of açaí (Euterpe oleracea Mart.) berry seeds from an agro-industrial residue. The nanomaterial was applied in the adsorption of cationic dyes. Screening tests were carried out for methylene blue (MB), resulting in an outstanding maximum adsorption capacity of 531.8 mg g-1 at 343 K, pH 10, 180 min. The kinetics followed a pseudo-second-order model and the isotherm of Fritz-Schülnder provided the best fit. Thermodynamic data show an endothermic process with entropy increase, typical of chemisorption. The proposed mechanism is based on the multilayer formation over a heterogeneous adsorbent surface, with chemical and electrostatic interactions of MB with the iron oxide nanoparticles and with the proanthocyanidins. The high adsorption efficiency was attributed to the network formed by the polymeric proanthocyanidins that entangled and protected the iron oxide nanoparticles, which allowed the reuse of the nanomaterial for seven cycles without loss of adsorption efficiency.

3D Architectural MXene‐based Composite Films for Stealth Terahertz Electromagnetic Interference Shielding Performance

AbstractThe terahertz frequency range is gaining popularity in security, stealth technology, and the future 6G network communication. For the control of severe terahertz electromagnetic interference (EMI) pollution, frequency‐selective stealth‐capable shielding materials are being explored to mask terahertz signals. For the realization of masking terahertz signals, the robustness, lightweight, and shape‐conformable materials with excellent terahertz EMI shielding/absorption are crucial. Here, the study reports the fabrication of 3D symmetric pyramidal architectural MXene composite films with frequency‐selective stealth performance characteristics via the facile drop casting method. With the high absorption capability of 2D MXene layers, the MXene composite films exhibit substantial terahertz stealth performance. 3D pyramidal microstructure design leads to frequency selective surface‐assisted reflection resonance in the frequency range of 0.6–1.1 THz. The MXene composite film demonstrates an outstanding maximum terahertz shielding effectiveness (SE) of up to 70.4 dB and a specific SE of 0.55 dB µm−1. These terahertz SE values exceed all of those for MX‐based shielding material designs reported in the literature. The investigation will open a new direction toward developing terahertz EMI shielding thin films with easy integration into any surface for stealth capabilities.

Characteristics of Regional GPS Crustal Deformation before the 2021 Yunnan Yangbi Ms 6.4 Earthquake and Its Implications for Determining Potential Areas of Future Strong Earthquakes

The 2021 Yangbi Ms 6.4 earthquake in Yunnan, China, occurred in an area where the Global Positioning System (GPS) geodetic observations are particularly intensive. Based on a detailed retrospective analysis of the GPS observations of about 133 stations distributed in the proximately 400 km × 400 km region that contains the area affected by the earthquake., we obtain a high-resolution GPS velocity field and strain rate field and then derive the present-day slip rates of major faults in the region with the commonly used half-space elastic dislocation model and constraints from the GPS velocity field. Furthermore, by calculating the seismic moment accumulation and release and deficit rates in the main fault segments and combining with the distribution characteristics of small earthquakes, we evaluate the regional seismic risk. The results show that (1) there was a localized prominent strain accumulation rate around the seismogenic area of the impending Yangbi Ms 6.4 earthquake, although this was not the only area with a prominent strain rate in the whole region. (2) The seismogenic area of the earthquake was just located where the strain direction was deflected, which, together with the localized outstanding maximum shear strain and dilatation rates, provides us with important hints to determine the potential areas of future strong earthquakes. (3) Of all the seismogenic fault segments with relatively high potentials, judged using the elapsed time of historical earthquakes and effective strain accumulation rate, the middle section of the Weixi–Qiaohou fault has a higher earthquake risk than the southern section, the Midu–Binchuan section of the Chenghai fault has a higher risk than the Yongsheng section and the Jianchuan section of the Jianchuan–Qiaohou–Lijiang–Xiaojinhe fault has a higher risk than the Lijiang section.

Exploring Efficient Blue Thermally Activated Delayed Fluorescence Emitters by Constructing Intramolecular Hydrogen Bonds

AbstractEfficient blue organic luminescent materials are highly desired for full‐color displays and white lighting based on the organic light‐emitting diode (OLED) technique, but the exploration of robust blue emitters remains challenging. In this work, a series of efficient blue thermally activated delayed fluorescence materials comprised of a benzonitrile acceptor, pyridine bridge, and carbazole‐based donors is designed and synthesized. Intramolecular hydrogen bonds are formed in these molecules, which improve molecular planarity and rigidity. These molecules exhibit excellent thermal stability, high photoluminescence quantum yields, and large horizontal dipole ratios. Highly efficient non‐doped and doped OLEDs are fabricated using these molecules as emitters, providing deep‐blue to sky‐blue lights with outstanding maximum external quantum efficiencies and good operational device lifetime. These results indicate that building intramolecular hydrogen bonds can be an effective strategy for the construction of efficient and robust blue emitters for OLED applications.