Browse Articles
Discover research articles across all indexed journals
Green LEDs with V-defects formed from intentional dislocation half-loops
Group III-nitride light emitting diodes (LEDs) suffer from poor efficiency for longer wavelength emission. This is partly due to increased polarization-induced barriers to vertical carrier injection at InGaN/GaN interfaces in the polar c-plane, where higher In-content is required for long-wavelength emission. Polarization-induced barriers can be bypassed by lateral carrier injection through the semipolar sidewalls of V-defects, which form at the apex of threading dislocations (TDs) during kinetically limited growth. This increases wall-plug efficiency (WPE) through the reduction of forward voltage (VF). TD and resulting V-defect density can be controlled through the formation of edge dislocation half-loops prior to V-defect opening. In this work, we demonstrate a green V-defect LED with optimized AlGaN caps with high external quantum efficiency (EQE) and WPE. The green V-defect LED demonstrated here with such a device structure achieves a peak EQE and a peak WPE of 43.9% and 37.0%, respectively.
Fluorine‐Rich Catalyst‐Induced Interphase Engineering to Enable the First Ah‐Level FeF <sub>3</sub> Conversion Solid‐State Batteries
ABSTRACT Conversion‐type FeF 3 cathodes promise ultrahigh energy density but suffer from sluggish reaction kinetics and interfacial instability in solid‐state battery systems. Here, we designed a fluorine‐rich NaBiF 4 @Bi 2 O 3 catalyst‐initiated polymer electrolyte via in situ ring‐opening polymerization of 1,3‐dioxolane. The NaBiF 4 phase initiates polymerization and serves as a fluorine reservoir, while Bi 2 O 3 participates in regulating the fluorine environment and contributes to the formation of a Li 3 Bi alloy clusters during cycling. This electrolyte enables the construction of LiF/NaF/Li 2 O‐reinforced solid electrolyte interface with embedded Li 3 Bi domains, delivering the homogeneous Li + flux and dendrite‐free Li deposition, enabling the stable Li‖Li symmetric cell cycling for 9700 h. The electrolyte demonstrates broad compatibility with both intercalation and conversion cathodes, achieving excellent cycling stability (800 cycles) in LiFePO 4 and high areal capacity (6 mAh cm −2 ) in LiNi 0.8 Co 0.1 Mn 0.1 O 2 . The Bi 2 O 3 component further catalyzes the interfacial dissociation of LiF at FeF 3 cathode and promotes the dynamic evolution of fluorine‐rich cathode electrolyte interphase, enabling the remarkable reversibility in FeF 3 conversion chemistry (641 mAh g −1 at 0.2 C and 300 cycles at 1 C). A 20‐layer FeF 3 ‐based pouch cell is demonstrated with a discharge capacity exceeding 1 Ah for the first time, marking a critical milestone toward practical high‐energy FeF 3 batteries.
Thermally tunable high-voltage breakdown and divergent avalanche nonlinearity in planar SnO2 nanofilm varistors
We present a planar, dopant-segregation-free SnO2 nanofilm varistor on a polycrystalline Al2O3 substrate that achieves a kilovolt-level breakdown voltage (V1 mA ≈ 759 V at 300 K). By directing the conduction pathway laterally across approximately 200 grain boundaries in series, this architecture overcomes the low-voltage limitations of conventional vertical thin films. Within the compliance-limited window, the device exhibits a pronounced divergent nonlinearity without bulk-resistance rollover. This steep current rise is analytically identified as an avalanche-type divergence, α(V)=V/(V*−V), driven by an electro-thermally assisted barrier collapse under localized Joule heating. To capture the full I–V trajectory across 200–500 K, we formulate a cascade model employing logistic soft-switch weights to govern the competitive transitions among Ohmic leakage, thermionic emission, and avalanche multiplication. The critical divergence voltage V* follows a strict Arrhenius scaling with an effective activation energy of ∼33 meV, reflecting how ambient thermal energy exponentially accelerates the pre-breakdown conductivity to reach the thermal runaway threshold. This planar nanofilm provides a lithographically defined, circuit-compatible platform, complementary to bulk ceramics, for on-chip transient voltage suppression.
Triboelectric E‐Skin for Robotic Perception of Hazardous Chemical Leaks
ABSTRACT The rapid identification of chemical composition, temperature, and dynamic behavior of leaked liquids by robots during accidental spills of hazardous chemicals would significantly reduce the potential risks to both human health and the environment. Here, we designed a flexible, palm‐shaped liquid‐sensing e‐skin (PSLSES) featuring 128 metal electrodes fabricated via flexible printed circuit (FPC) technology and coated with a fluorinated ethylene propylene (FEP) film. By capturing the local triboelectrification signals along the droplet's trajectory, PSLSES enables multimodal dynamic liquid sensing, simultaneously achieving liquid composition identification, temperature sensing, as well as droplet motion tracking through visualized trajectory patterns. Integrated with a one‐dimensional convolutional neural network (1D CNN), PSLSES achieves an ultrahigh identification accuracy of 99.5% across 21 types of liquids, with a high monitoring resolution down to the ppb level and 98% accuracy in identifying liquid temperature. This includes deionized water, acids, bases, salts, and organic solutions, demonstrating broad liquid identification versatility. Compared with previously reported E‐skin systems, it achieved faster identification (0.3 s), a lower detection limit (0.1 ppb), broader liquid recognition, and higher accuracy. The integration of PSLSES into wearable robotics systems opens new ways for robots to assist humans in analyzing and handling chemical leakage in hazardous environments.
A reconfigurable, broadband light-field mapper for illusionary effects
The manipulation of light field is pivotal for advancing optical technologies. Here, we present a reconfigurable optical system based on lens-fiber networks that function as a light-field mapper, capable of generating macroscopic optical illusions. This system employs a lens array to decompose the incident light field, which is then transmitted via a fiber network and reconstructed by a second lens array. This process establishes a reconfigurable mapping between input and output light fields. Through proof-of-principle experiments, we demonstrate “free-space” illusion devices, where light rays traverse the mapper—including embedded opaque objects—in straight lines, effectively mimicking propagation through free space. Our work introduces a flexible platform for light-field manipulation with potential applications in virtual reality, optical computing, and secure communication.
Microwave-photonic control of optically accessible spin defects in diamond
A growing variety of optically accessible spin qubits have emerged in recent years as key components for quantum sensors, computers, and memories. However, the scalability of conventional spin-based quantum architectures remains limited by direct microwave delivery, which introduces thermal noise, electromagnetic crosstalk, and design constraints for cryogenic, high-field, and distributed systems. In this work, we present a unified framework for RF-over-fiber (RFoF) control of spins accessible through optically detected magnetic resonance (ODMR) spectroscopy of nitrogen-vacancy (NV) centers in diamond. The RFoF platform relies on an intensity-modulated 1310 nm laser carrying microwave signals over fiber and a high-speed photodiode for optical-to-electrical conversion to drive NV spin transitions. We report an RFoF power-conversion efficiency of 3.42% for an RF output PRF,out=−5.5 dBm at 2.87 GHz, enabling clear resolution of Zeeman splitting in proportion to an applied magnetic field. The RFoF architecture provides a path toward low-noise, thermally isolated, and cryo-compatible ODMR systems at sub-THz frequencies, thus bridging conventional spin-based quantum sensing protocols with emerging distributed quantum technologies.
Physical reservoir computing using all-solid-state LaZrO/InO electric double-layer thin-film transistor
Machine-learning-based AI prediction drives rising electricity use and processing demands, raising sustainability concerns. Reservoir computing reduces training by optimizing only output weights, and physical reservoir computing (PRC) further accelerates processing by exploiting physical phenomena. Yet, many hysteresis-based PRCs depend on costly or unstable materials and fabrication methods unsuited to scale, limiting practical deployment. This study evaluated the potential of all-solid-state electric double-layer (EDL) thin-film transistors, incorporating a lanthanum zirconium oxide solid electrolyte and an indium oxide semiconductor, for PRC applications. The drain current (ID) and gate current (IG) as functions of gate voltage (VG) displayed pronounced hysteresis, with the extent of hysteresis dependent on both the drain voltage (VD) and the VG scanning rate. The ID response to pulsed VG inputs demonstrated a clear dependence on the preceding input pulse VG, thereby validating the device's short-term memory properties. In the second-order nonlinear autoregressive moving average task, the minimum normalized mean square error (NMSE) was 7.71 × 10−3 and 7.56 × 10−3 when utilizing the IG response as virtual nodes comprising 40 and 80 points, respectively. Furthermore, the NMSE demonstrated a strong correlation with memory capacity, particularly with the coefficient of determination associated with the correlation for up to two previous data points. The all-solid-state EDL-TFT-based physical reservoir, with its miniaturization, air stability, and broad pulse operating range, offers a scalable and robust platform that could enable practical integration of PRC into next-generation AI devices, advancing energy-efficient and durable hardware solutions.
An engineered metal-to-insulator transition in a two-dimensional network of degenerate phosphorus quantum dots in silicon
Phosphorus quantum dots (QDs) in silicon are a prominent candidate for semiconductor quantum computing based on donor spins. In this work, we report the formation of degenerate phosphorus QDs with a radius of 3 nm confined in a two-dimensional plane in silicon. A multilayer of SiO2/POx/SiO2 on Si substrate is first deposited by atomic layer deposition, which serves as the capping layer, doping source, and doping mask. Defective channels in the SiO2 doping mask layer are then created by random argon (Ar) ion implantation. Finally, phosphorus dopants from the doping source layer, driven by pulsed laser annealing, diffuse through the defective channels in SiO2 into Si substrate, forming phosphorus QDs confined in a two-dimensional (2D) plane near the Si surface. By reducing the Ar dose, we observe a sharp metal-to-insulator transition (MIT) in the resulting 2D electron system. Based on the MIT model for quantum dots, we find that each Ar ion implantation has a chance of only 6.4%–8.1% to create a phosphorus quantum dot.
Recent Advances in Cholesteric Liquid Crystal Elastomers: Fabrication, Functionalization, and Applications
ABSTRACT Cholesteric liquid crystal elastomers (CLCEs) are a vibrant subset of photonic materials exhibiting extraordinarily mechanochromic properties that make them an ideal platform for the development of displays, sensing, anti‐counterfeiting, and camouflage technologies. In recent years, researchers have increasingly extended the structure and morphology of CLCEs to uncover their fascinating functionalities and promising applications. In this review, the historical development of CLCEs is retrospect, recent advances in the preparation methods are highlighted, and the well‐ordered CLCEs with extended functionality are introduced. Within this scope, we highlight the unique advantages of CLCEs and present recent progress in expanding their structural, morphological, and functional versatility. We conclude with an outlook on current challenges and near‐term application opportunities.
Quantitatively separating superexchange and direct exchange interactions in 2D ferromagnetic materials
Two-dimensional (2D) ferromagnetic (FM) materials are promising candidates for emerging energy-efficient electronic devices. Various modulation strategies have been proposed to increase their rather low Curie temperatures, including ligand substitution, strain, and voltage control. Fundamentally, the improvement of the Curie temperature can be attributed to strengthened FM superexchange interactions, weakened direct exchange interactions, or both. With only a qualitative understanding, the effects of the modulation strategies on the entangled superexchange and direct exchange interactions, and hence on the Curie temperatures, often cannot be unambiguously determined. Therefore, we propose a descriptor-based computational approach to quantitatively separate the contributions of the superexchange and direct exchange interactions to each magnetic exchange parameter. The approach combines density-functional calculations with the exchange mechanisms, and we apply it to the archetypal 2D magnetic monolayers CrSX (X= Cl, Br, or I). This work provides a basis for rationally designing and modulating 2D FM materials to achieve high Curie temperatures.
Electrothermal Oxidation of Ethylene Glycol Over Co <sub>3</sub> O <sub>4</sub>
ABSTRACT Purely electrocatalytic routes for the selective oxidation of alcohols are often limited by overpotential, mass transport, and kinetics due to multiple proton‐coupled electron‐transfer steps. We report the electrothermal oxidation of ethylene glycol (EG) over cobalt oxide (Co 3 O 4 ) spinel acting simultaneously as an electrocatalyst and a solid thermocatalyst by integrating enhanced temperature and 15 bar O 2 pressure in alkaline electrolyte at controlled current density. Enhanced EG oxidation was observed with increasing temperature from 30°C to 90°C. Glycolate and formate were the main products, while oxalate was only detected in long‐term experiments at lower current densities. Selectivity shifted from formate at low temperature, caused by electrochemical C–C cleavage, to rapid glycolate desorption at increased thermal conditions. The virtual Faradaic efficiencies (vFEs), which are the sum of all charge stored in the reaction products, reached 180% at 90°C, confirming that thermal oxidation by O 2 at high pressure contributes to an additional oxidative electron transfer at the solid‐electrolyte interface beyond the applied electrochemical potential. These findings demonstrate that superimposing thermal and electrochemical driving forces boosts performance and enables control over reaction pathways. The approach establishes a conceptual and practical framework toward synergy between electro‐ and thermocatalytic heterogeneous alcohol oxidation toward sustainable chemical transformations.
Geometric and size effects on the thermal conductivity of fishbone-like nickel nanowires
Thermal conductivity at the nanoscale often deviates significantly from that of bulk materials due to the mean free path of heat carriers becoming comparable to the system's dimensions, which challenges traditional heat transfer models. While magnetic nanowires are widely employed in various applications, their thermal properties remain poorly understood. This study investigates the thermal conductivity of nickel nanowires with a fishbone-like structure, focusing on the influence of flank angles (45°, 90°, and 135°) and characteristic sizes. Our results show that thermal conductivity decreases with decreasing flank angle relative to the heat flow direction, with this effect becoming negligible as the wire width approaches the microscale. Additionally, the thermal conductivity demonstrates a stronger size dependence in nanowires with acute flank angles (45°) compared to those with obtuse angles (135°). These results experimentally demonstrate a coupled effect of flank angle and characteristic width on the thermal conductivity of fishbone-like nickel nanowires, providing new insights into geometry-dependent thermal transport and offering guidance for the structural design of efficient thermal management systems.
A metal-free phosphorus–oxygen/nitrogen–carbon configuration as an effective metal–nitrogen–carbon analog for accelerated lithium-sulfur redox kinetics
The practical deployment of lithium-sulfur batteries is limited by the polysulfide shuttle effect arising from sluggish sulfur redox kinetics. While metal–nitrogen–carbon (M–N–C) catalysts are effective in promoting sulfur conversion, their synthesis suffers from metal aggregation and the mass penalty of transition metals reduces the practical energy density. Here, we design a metal-free phosphorus–oxygen/nitrogen–carbon (P–O/N–C) electrocatalyst that functionally mimics M–N–C configurations, offering simplified synthesis without metal-related issues. Spectroscopic analysis confirms the formation of P–O/N–C coordination sites. Electrochemical evaluation reveals that PONCNT exhibits superior catalytic activity in accelerating polysulfide conversion, particularly for the rate-limiting Li2S nucleation process, with a low Tafel slope and high Li2S deposition capacity. Crucially, this catalytic behavior faithfully reproduces the hallmark of M–N–C catalysts: moderate polysulfide adsorption but dramatically accelerated conversion kinetics, demonstrating that enhanced kinetics, not strong trapping, is the primary origin of its performance. This work establishes a metal-free strategy for constructing M–N–C analogs, opening a pathway toward lightweight, low-cost electrocatalysts for high-energy lithium-sulfur batteries.
Diastereoselective Synthesis of Axially Chiral Skipped Ene–Allenes Containing a Quaternary Stereocenter by Cyclopropene–Allene Metathesis
ABSTRACT Functionalized skipped ene–allenes (1,4‐enallenes) bearing an all‑carbon quaternary stereocenter were prepared by a diastereoselective ring‐opening metathesis of mesomeric cyclopropene and allene for the first time. A strategic pairing of a broad range of allenes with cyclopropenes revealed a new way to access high reactivity and chemoselectivity, and delivered products with excellent diastereoselectivity at low Ru catalyst loading. Mechanistic studies delineate the reactivity order of the metathesis partners, identify the key diastereoselectivity‐determining step, and clarify the main factors governing the cross‐/homo‐metathesis ratio and diastereoselectivity. The presence of allenyl–Bpin, –silyl, and –germanyl groups allows highly chemoselective functionalization at the allene over the terminal alkene, demonstrating the synthetic utility of the products as versatile intermediates in organic synthesis
Uniaxial strain-induced spin textures transition in the kagome magnet Fe3Sn2
The mechanical control of magnetism represents a promising frontier in spintronics. However, its experimental application is mostly confined to the elastic strain regime, which limits the exploration of magnetic responses under larger strain. Here, by applying uniaxial compressive strain to induce plastic deformation in an Fe3Sn2 lamella, we directly observed the room-temperature transformation of stripes into an intermediate state comprising vortices, stripes, and antivortex chains. This intermediate state was accessed by cycling either the magnetic field under fixed strain or the strain under a fixed magnetic field. The mixed state is metastable and evolves into vortices under the applied magnetic field. Micromagnetic simulations indicate that large strain induces a transition from out-of-plane easy axis to easy-plane anisotropy in Fe3Sn2, thereby facilitating the stripe-to-vortex transformation. By unraveling the strain-mediated interactions between magnetic anisotropy and domain structures, we provide crucial insights for the development of strain-controlled spintronic devices.
Interface charge inhomogeneity at Al2O3/OH-diamond (111) characterized by time-resolved scanning nonlinear dielectric microscopy
Inversion-channel diamond metal-oxide-semiconductor field-effect transistors (MOSFETs) suffer from channel mobility far below the bulk value, yet the microscopic origin of this limitation has not been fully elucidated. Because carriers in the inversion layer are confined close to the MOS interface, spatial inhomogeneity of interface charges is expected to play an important role through Coulomb scattering. However, such effects cannot be fully assessed by conventional macroscopic capacitance–voltage (CV) profiling. Here, we investigated local charge states at the Al2O3/OH-diamond (111) interface used in inversion-channel diamond MOSFETs by local CV profiling based on time-resolved scanning nonlinear dielectric microscopy. The measured local CV profiles exhibit substantial spatial fluctuations with clustered non-uniformity. The corresponding interface charge fluctuation, estimated from the local CV profiles, was smaller than that previously obtained for an as-oxidized SiO2/SiC interface but larger than that for a nitrided SiO2/SiC interface. Numerical device simulations incorporating the experimental data indicate that these spatially fluctuating interface charges can induce Coulomb scattering more strongly than expected from the macroscopic interface characterization. This leads to a significant reduction in the peak field-effect mobility.
Bio-based self-powered triboelectric sensor for intelligent early-warning monitoring in rhythmic gymnastics
Rhythmic gymnastics is characterized by high flexibility, explosive power, and multi-joint coordination; during vertical jumps (VG), kick leg (KL), split leap (SL), and landing, the lower limbs are readily exposed to complex mechanical loads and injury. To address the limitations of current motion-capture systems, force platforms, and inertial sensing technologies in portability, continuous monitoring, and power supply, this study develops a bio-based fiber/graphene-enhanced triboelectric nanogenerator (BG-TENG). The graphene conductive network, in concert with a Kapton elastic layer, Cu electrode, and PTFE negative tribolayer, forms a flexible contact-separation sensor. The device achieves optimal output at 3 wt. % graphene loading and exhibits stable voltage responses and favorable cycling performance under varied velocities, loads, and bending angles. When deployed on the plantar region, ankle joint, and knee joint and validated in conjunction with an IMU, the BG-TENG effectively characterizes ankle acceleration, knee flexion-extension angle, and plantar deformation. Using multichannel signals, a recognition model was established for correct and injury-state movements involving VG, KL, and SL, enabling accurate classification of six action categories and real-time visualized early warning through an upper computer system. This system offers a green, flexible, and wearable intelligent-monitoring strategy for early warning of sports injuries, movement-quality assessment, and personalized training feedback.
DRP1-mediated mitochondrial fragmentation is a druggable vulnerability in multiple myeloma
Mitochondrial dynamics is a key regulator of cellular homeostasis, orchestrating metabolic reprogramming that fuels tumor progression and treatment resistance. In multiple myeloma (MM), however, the functional relevance of mitochondrial remodeling has not been fully defined. Using ultrastructural analyses, we reveal that MM cells display a highly fragmented mitochondrial network, a phenotype further exacerbated in both cell lines and primary MM cells resistant to proteasome inhibitors. Transcriptomic profiling across multiple patient-derived datasets consistently demonstrated upregulation of DNM1L gene, which encodes the mitochondrial fission GTPase DRP1, particularly in relapsed and refractory MM, and revealed a significant association with inferior overall survival. Disrupting mitochondrial fission, either through genetic targeting of DNM1L or pharmacologic inhibition of DRP1 with the selective small molecule inhibitor Drpitor1a, resulted in pronounced mitochondrial dysfunction, impaired oxidative phosphorylation, and potent anti-myeloma activity in vitro, culminating in a hybrid cell death program with a predominant apoptotic component accompanied by ferroptotic features. These effects were recapitulated in vivo in a bortezomib-resistant xenograft model, where either DNM1L depletion or DRP1 inhibition produced similar outcomes. Mechanistically, the transcription factor c-MYC upregulated DNM1L expression, and DRP1-dependent mitochondrial fragmentation sustained MYC-driven oxidative metabolism and lipid synthesis. Altogether, these findings establish aberrant mitochondrial fission as a pathogenic hallmark of MM and highlight DRP1 inhibition as a promising therapeutic approach, especially for relapsed or refractory disease.
A LiNbO3 A1 Lamb-wave resonator with Archimedean spiral electrodes
Lithium niobate (LiNbO3) thin-film-based A1 Lamb-wave resonators hold significant promise for high-frequency broadband radio frequency acoustic devices because of their high phase velocity and large electromechanical coupling. Most reported devices employ straight-strip interdigital electrodes. Although this configuration is relatively mature for A1-mode excitation, there remains room for further exploration in structural topology and coordinated device-parameter design. Here, we experimentally demonstrate a suspended A1 Lamb-wave resonator based on Archimedean spiral electrodes. The proposed structure incorporates a central release window and can be extended to multiple electrode pairs and turns, thereby providing greater design flexibility. Experimental results show that a one-pair, two-turn spiral resonator based on a Z-cut LiNbO3 thin film realizes the target A1-mode resonance near 4 GHz. At a duty factor of 0.38, the device achieves an electromechanical coupling coefficient of 30.17%, a Bode-Q of 471, and a figure of merit (FoM) of 142, indicating good overall performance. In addition, extension to multi-pair, multi-turn spiral electrodes enables tunable static capacitance (C0), highlighting the potential of this configuration for the co-design of resonant unit parameters. These results indicate that the Archimedean spiral electrode provides a viable structural solution for high-frequency A1 resonators and offers new insights into the topology design and performance optimization of related devices such as filters, sensors, actuators, and antennas.
Brightening otherwise-weak molecular electroluminescence via intermolecular energy transfer
Manipulating the electroluminescence of organic molecules is important for the development of advanced organic light-emitting diodes (OLEDs). Here, we demonstrate a single-molecule sensitization strategy to brighten an otherwise-weak molecular emitter by using the scanning tunneling microscope induced luminescence (STML) technique. We show that while the free-base phthalocyanine (H2Pc) molecule is a bright emitter, the molecule upon double deprotonation ([Pc]2−) exhibits electroluminescence that is suppressed by three orders of magnitude. The extremely weak emission of [Pc]2− is traced to a misalignment of its frontier orbitals with the substrate, which fundamentally shifts the excitation from an efficient carrier-injection mechanism in H2Pc to an inefficient inelastic electron scattering process in [Pc]2−. However, by bringing a zinc-phthalocyanine (ZnPc) molecule close to it to form a donor–acceptor dimer (ZnPc–[Pc]2−), we introduce an intermolecular energy transfer pathway that enhances the luminescence of [Pc]2− by approximately 135-fold. Furthermore, combined with theoretical calculations, the dependence of STML spectra on the intermolecular distances (d) indicates that the energy-transfer mechanism is dominated by Förster resonance energy transfer. Our findings demonstrate a viable strategy for overcoming molecular-level charge-injection limitations and provide actionable guidelines for designing OLED architectures with enhanced luminescence efficiency.