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Homologous Ladder Cyclohexasilanes
Abstract We report the synthesis of five new examples of ladder cyclohexasilanes, possessing up to three consecutive fused rings and differing in relative ring fusion configuration and side chain structure. By coupling a 1,4‐dipotassiooligosilyl dianion to a cyclohexasilane, we obtained bi‐ and tricyclic ladder cyclohexasilanes. Combined experimental and theoretical studies suggested that annulation could favor the cis configuration under kinetic control, while the trans configuration predominates under thermodynamic control. Computational studies show that with each additional ring in the trans ‐diastereomeric series, the predicted onset of light absorption shifts to longer wavelengths.
Minimal addition of fumed nanoparticles suppresses droplet splashing
Droplet splashing is a common issue in various applications, from industrial processes to natural phenomena. This study demonstrates a method for suppressing droplet splashing by adding minute concentrations (as low as 0.1 wt. %) of fumed silica, titania, alumina, or magnesia nanoparticles to glycerol–water mixtures. Surprisingly, the suppression is more effective at higher impact velocities, where splashing is typically more severe. Our high-speed imaging and rheological measurements reveal that this effect arises from the emergence of elasticity in the nanofluids at extreme shear rates. This emergent elasticity, due to particle agglomeration and network formation, is demonstrated in the dilute fumed metal oxide nanofluids. Based on our findings, we propose a splashing threshold applicable to all liquids, including the non-Newtonian nanofluids studied here. This threshold is validated using Drop Impact Viscometry to accurately measure viscosity at high shear rates. These results offer an approach to designing splash-resistant liquids with minimally altered bulk properties.
Charge transfer rate modulated energy loss in indoor organic photovoltaic cells
Minimizing energy loss is pivotal for achieving high-performance indoor organic photovoltaic (IOPV) cells, where charge transfer (CT) rate critically governs exciton-to-charge conversion efficiency. Nevertheless, the fundamental correlation between CT rate and energy loss remains insufficiently understood. In this study, we systematically investigate how CT rate affects the radiative and non-radiative energy loss in IOPV devices employing PBDB-T donor and three wide-bandgap BTA3 series acceptors. A developed global fitting model for charge separation pathways demonstrates that the intra-moiety delocalized excitations and CT states show comparable contributions to exciton dissociation efficiency (each accounting for approximately 50%). Notably, our findings reveal that excessive driving forces can paradoxically reduce CT rate, resulting in prolonged existence of CT states at the donor:acceptor interfaces that amplifies radiative and non-radiative recombination. The lower CT rate-mediated energy loss becomes increasingly dominant under indoor weak illumination compared to standard solar conditions due to reduced density of CT states and intensified influence of trap states. This elucidates a CT rate-dependent energy loss mechanism that warrants greater consideration in the design of IOPVs. These results highlight the importance of CT rate modulation for suppressing energy loss, providing valuable insights for the rational design of photovoltaic materials for diverse indoor energy harvesting applications.
Dual Cofactor Co‐Decorated Covalent Organic Framework as an Electron Transfer Regulator for Biomimetic Dioxygen Activation
Abstract Mimicking the synergy of multiple active sites of oxygenase to achieve selective O 2 activation for various oxidations is a very challenging but meaningful task. By introducing the reduced nicotinamide adenine dinucleotide (NADH) active site dihydropyridine amido (DHPA) moiety and heme, a dual cofactor co‐decorated covalent organic framework (COF) was obtained to duplicate the synergistically catalytic function of the cytochrome P450 for biomimetic O 2 activation. Covalent co‐decoration of dual cofactors in COFs ensures the rapid photogenerated electron transfer from DHPA to heme Fe III to generate Fe II , selectively activating O 2 to form Fe III −O 2 •− resembling the cytochrome P450 for improving the performance of alcohol oxidation, avoiding conventionally complex multistep cofactor shuttling and regeneration. Control experiments of a COF analogue containing heme but not DHPA suggested that this dual cofactor construction strategy renders COFs excellent activity and selectivity for O 2 activation. As far as we know, this represents the first case of introducing dual cofactor into COFs to echo the cytochrome P450. The well‐defined structural characters and the finely modified bioactive properties open a new avenue to develop novel COFs, which not only augment the diversity of the COF family but also broaden the application of COFs in the field of biomimetic catalysis.
Mitigation of self-heating in AlGaN/GaN HEMTs using transferred LPCVD-grown h-BN
With the increasing power density of GaN-based power devices, the self-heating effect has become a significant bottleneck, impacting device reliability and performance, which makes effective thermal management essential. Hexagonal boron nitride (h-BN), with its high thermal conductivity and excellent electrical insulation, offers a promising solution for heat dissipation. In this Letter, we demonstrate that the transferred low-pressure chemical vapor deposition-grown h-BN effectively mitigates self-heating in AlGaN/gallium nitride high electron mobility transistors. All 12 tested devices showed increased current after BN transfer. The average current density in the saturation region improved from 819 to 924 mA/mm, and the current retention rose from 89% to 98%. Thermo-reflectance measurements revealed a significant reduction in channel temperature from 179 to 115 °C under a power density of 21 W/mm. The improvement is attributed to the high in-plane thermal conductivity of h-BN, which is proven by the hotspot models. This approach shows promise as a practical method to reduce self-heating and enhance the thermal reliability of GaN-based power transistors.
Achieving optimized spin–orbit torque efficiency and energy savings with Pt1−x(VO2)x/Co multilayer films
Spin–orbit torque (SOT)-driven magnetization switching has demonstrated exceptional scalability, high-speed operation, and low-power characteristics in spintronic devices, making it a promising candidate for next-generation energy-efficient memory technologies, such as spin–orbit torque magnetic random-access memory (SOT-MRAM). Traditional Pt-based materials often enhance the SOT efficiency through alloying or doping, but these approaches typically involve trade-offs between power consumption and SOT performance. To address these limitations, this study proposes an innovative strategy by uniformly incorporating VO2 into Pt, achieving dual optimization of SOT efficiency and electrical performance. The magnetization switching current density was reduced to 3 × 106 A/cm2, corresponding to a damping-like torque efficiency (ξDL) of 0.27, and the volume power density decreased to 5.1 × 1011 mW cm−3. The values are reduced by approximately ninefold and 40-fold, respectively, compared to pure Pt. Thus, VO2-doped Pt provides a pathway for the design of low-power, high-efficiency SOT-MRAM devices.
A high-entropy Al-based halide electrolyte enables cost-effective, high-performance all-solid-state batteries
Rare-earth halides are promising solid electrolytes (SEs) because of their comprehensively superior ionic conductivity, excellent electrochemical oxidative stability, and mechanical softness. However, their application is limited by their reliance on rare earth and expensive elements. While chloroaluminates offer an economical alternative, they typically suffer from low ionic conductivities. This study reports a high-entropy aluminum (Al)-based halide SE, Li1.245Al0.745(ZrPSiB)0.0636O0.7Cl3.1, synthesized from inexpensive precursors using a high-entropy strategy. Rietveld refinement with an internal standard reveals that mechanical milling produces this composition with ∼39.7% amorphous content alongside a monoclinic LiAlCl4 phase. X-ray photoelectron spectroscopy elucidates the competitive roles of non-bridging oxygen and bridging oxygen within the modified halide framework. This structural modification results in a tenfold increase in ionic conductivity (0.2 mS cm−1 at 25 °C) compared to pristine LiAlCl4. All-solid-state batteries (ASSBs) employing the Li1.245Al0.745(ZrPSiB)0.0636O0.7Cl3.1 as a catholyte with single-crystalline LiNi0.8Co0.1Mn0.1O2 cathodes demonstrate excellent cycling stability over 200 cycles at upper cutoff potentials of 4.2 and 4.3 V vs Li/Li+. This work highlights the potential of high-entropy chloroaluminates as cost-effective solid electrolytes for ASSBs.
Exploring Excited State Proton Transfer in Thin Films Under Vibrational Strong Coupling
Abstract Molecular structure, solvent/matrix, the surrounding environment, and molecular vibrations can influence the excited‐state proton transfer (ESPT) process. Theoretical studies predict that light‐matter strong coupling can modify the energy barrier for proton transfer reactions. Here, we experimentally explore the role of vibrational strong coupling (VSC) on the ESPT using the weak photoacid, 7‐hydroxy‐1‐naphthalenesulfonate (N8S) as the probe. The ESPT in N8S can occur through a solvent/matrix bridge connecting the proton‐donating and accepting units. To check the role of VSC, we embedded N8S in a poly(vinyl alcohol) (PVA) matrix and strongly coupled the ─OH stretching vibrational modes of PVA. The steady‐state and time‐resolved emission analysis reveal that the quantum yield of RO − emission and the ESPT rate constant enhance by a factor of two under VSC, compared to the noncavity, half‐cavity, and off‐resonance films. Our findings indicate that VSC can be a tool to control the proton transfer processes, opening avenues for developing physically tunable photoacid‐based sensors.
Synchronization of propagating spin waves in spin Hall oscillators: A micromagnetic study
In this study, we investigate the synchronization of propagating spin waves in a spin-torque oscillator device layout using micromagnetic simulations. This design enables individual probing of the dc current in each oscillator, allowing precise control over the synchronization state and providing direct phase measurement. Our findings reveal that two adjacent oscillators achieve phase locking when they maintain a constant phase difference, either in-phase or anti-phase, depending on their separation distance. This work offers insights into spin-torque oscillator synchronization mechanisms and paves the way for improved control and functionality in spintronic devices.
Ligand-assisted ion exchange enabled ultralong compositionally graded perovskite nanowires
The bandgap engineering of halide perovskites via ion exchange has attracted extensive attention in recent years. However, the composition tuning at the microscale is still challenging due to complicated procedures for achieving spatial resolution. Herein, we report a facile and efficient approach for fabricating ultralong, compositionally graded CsPbBr3 − 3xI3x nanowires (NWs). By incorporating a ligand barrier onto the NW surface, the ion exchange is confined only to both ends of the NWs, leading to a compositional gradient extending over tens of micrometers along individual NWs. Further study shows that the funnel-like energy band structure facilitates the transport of photo-generated carriers, as evidenced by the excellent spectral and optoelectronic performance of the gradient NW device. Such ligand-assisted, spatially resolved band engineering is conducted at ambient conditions without additional process of nanofabrication or micro-manipulation, which is suitable for integration into miniaturized optoelectronic devices.
Switchable nonlinear optical isolator in MXene
We investigate the microdynamics of MXene (Ti3C2Tx) flakes under the influence of two opposing effects: light-induced alignment and Brownian motion. The interplay between these effects gives rise to spatial self-phase modulation patterns. Light-induced alignment initiates the formation of diffraction rings, while Brownian motion acts to counter this process. The dominance of each effect is governed by the optical absorption property of the solvent. Leveraging this mechanism, we develop a switchable nonlinear optical isolator using a single-phase MXene dispersion. Upon application of a control beam, the device transitions from a nonlinear optical isolator that exhibits ring patterns in only one direction to a symmetric configuration that displays ring patterns in both directions. This simple device holds promises for applications in optical switching and logic operations.
ALD-derived high-<i>k</i> ZrAlOx dielectrics for boosted performance of CNTs/ZTO CMOS inverter
In this study, high-k dielectric zirconium aluminum oxide (ZrAlOx) and zirconium oxide (ZrO2) have been fabricated via atomic layer deposition. The effects of Al doping on the capacitance characteristics, leakage performance, surface roughness, and chemical composition of the ZrO2 and ZrAlOx gate insulators are investigated. ZnSnO thin-film transistors (ZTO TFTs) and carbon nanotube (CNT) TFTs have been integrated into the high-k dielectrics. By combining CNT TFTs with ZTO TFTs, complementary metal–oxide–semiconductor (CMOS) inverters have been developed, and the role of Al doping in enhancing the electrical characteristics of both TFTs and CMOS inverters has been investigated. The results show that, compared to CMOS inverters with ZrO2 gate insulators, those with ZrAlOx allow carriers to transport more smoothly at the interface and reduce carrier scattering, demonstrating a better performance with a smaller hysteresis (0.21 V), lower power consumption (5.0 × 10−8 W), higher gain (43.8), and better voltage transfer characteristics. This research provides theoretical support and practical value for the development of next-generation integrated circuits.
Cryogenic magnomechanics for thermometry applications
Cavity magnomechanics combines strong coupling between magnons in a dielectric material and microwave cavity photons with long-lived mechanical resonances. Forming a triple resonance condition, this hybrid quantum system promises many advantages in quantum technologies, yet has never been studied at the cryogenic temperatures required to reveal such quantum properties. We report the observation of magnomechanics at cryogenic temperatures down to 9 K. The experiment was conducted using a yttrium iron garnet sphere inside a microwave cavity, where we measured both the thermomechanical motion and the temperature-dependence of the magnon linewidth.
NH3 release during the evaporation of different types of atmospheric precipitation: A case study in Changchun, China
Comparison of the inter-recti distance in nulliparous women measured in supine and standing positions using ultrasound imaging
The cross-sectional area of the erector spinae muscle is an adverse indicator for patient with acute exacerbation of chronic obstructive pulmonary disease
A novel green biosynthesis approach and structural characterization of Ag–Fe bimetallic nanoparticles using the red alga Galaxaura rugosa
Abstract A novel green and eco-friendly approach has been used to biosynthesize Ag–Fe bimetallic nanoparticles (Ag–FeBNPs) by using the water extract of the red alga species; Galaxaura rugosa. The surface plasmon resonance band of Ag–FeBNPs is positioned at 327 nm. X-ray diffraction analysis (XRD) illustrated the crystalline nature of biogenic nanoparticles with average diameters of 32.6 nm. Transmission electron microscopy (TEM) and selected area electron diffraction (SAED) showed that the particles have a crystalline spherical shape with a size range from 19.95 to 37.11 nm. Scanning electron microscopy (SEM) and Energy dispersive analysis (EDAX) give the surface morphology and elemental composition of Ag–FeBNPs, which are spherical in high intensity. Fourier transmittance infrared spectroscopy (FTIR) showed various stretching vibrations at 3421, 1598, 1384, 1035, and 865 cm−1. These findings suggest that biomolecules play a crucial role in forming and stabilizing Ag–FeBNPs. Zeta potential values show − 16.1 mV. This study demonstrates the promising future of Ag–FeBNPs for nanobiotechnology and nanoscience, offering an environmentally friendly and simple approach for nanoparticles biosynthesizing. In addition, the synthesized Ag–FeBNPs exhibit properties that make them suitable for potential applications in biomedical fields, environmental remediation, and catalysis.
Lack of association between the rs1842681 polymorphism of the LOC105372028 gene and functional outcomes after stroke
Genomic epidemiology of Mycobacterium tuberculosis in Wales
Abstract Identification of factors contributing to tuberculosis (TB) transmission can guide targeted measures to reduce morbidity. Varying findings for factors associated with TB genomic clustering exist. We describe Mycobacterium tuberculosis strain diversity, drug-resistance, and ongoing transmission in Wales using single nucleotide polymorphisms (SNP)-based typing to infer lineage and clusters. TB cohort data on isolates from Welsh residents from 2012 to 2022, patient level data from the National TB Surveillance System and SNP-based data, were merged. Descriptive epidemiology and logistic regression modelling were used to identify factors associated with genotypic clustering. 215 cases were included in the cluster analysis (66% male and 46% born outside of the UK); 115/215 belonged to 30 genomic clusters belonging to lineages 2–4. Most clusters corresponded to Lineage 4 and were distributed within South Wales. There were significant differences in the distribution of ethnicity, age group, and deprivation (Welsh Index of Multiple Deprivation, WIMD) in our sample compared to the Welsh population. Resistance to rifampicin and isoniazid and predicted resistance to ethambutol, aminoglycosides, pyrazinamide, and quinolone was low. Factors associated with increased odds of clustering included being UK-born and having pulmonary disease. Due to the identification of the above factors associated with TB genomic clustering, as well as the differences in ethnicity, age group, and WIMD quintile, prevention strategies for TB screening targeted towards these groups may be considered. Future work may evaluate the utility of additional control measures within these populations when the onset case in a genomic cluster has any of these characteristics.