Defects govern the electrical, mechanical, optical, and diffusion-related properties of metal oxides, making defect engineering a powerful strategy for tailoring material performance. Conventional approaches, including thermal annealing, chemical doping, ion implantation, and atmospherecontrolled processing, are largely constrained by equilibrium processing and provide limited control over defect type, spatial distribution, depth, and evolution. Pulsed laser processing offers a versatile platform for localized, non-equilibrium defect engineering in metal oxide nanomaterials. Hierarchical defect structures, including vacancies, dislocations, grain boundaries, and interfaces, can be generated and manipulated over multiple length scales to enhance charge transport, optoelectronic performance, and plasticity. These defects can also accelerate diffusion for low-temperature sintering and nanojoining. Beyond summarizing recent advances, this Perspective highlights emerging directions in defect-dynamics design, including the controlled generation, migration, interaction, and stabilization of defects through adaptive laser processing, as well as control over defect depth, orientation, and time-dependent evolution. Finally, predictive relationships among laser parameters, defect dynamics, and functional properties are expected to emerge through the integration of in situ characterization, multiscale modeling, and artificial intelligence, enabling application-specific design of advanced metal oxides.

COVID-19 remains a global health threat due to its rapid transmission and the emergence of new variants. Despite advances in vaccines and antiviral treatments, there remains a pressing need for alternative strategies that prevent viral entry at the earliest stage. Heparin, recognized for its electrostatic affinity toward the SARS-CoV-2 spike protein, has demonstrated potential in disrupting viral attachment. In response to this challenge, the present study proposes a modeled DNA origami-linker-heparin construct that integrates a DNA origami U-shaped cage with heparin through a spermidine-based linker, designed to investigate the structural and energetic behavior of tethered heparin chains in the presence of the SARS-CoV-2 RBD. Three hybrid complexes with varying heparin lengths were designed and evaluated using all-atom molecular dynamics simulations at 300, 310, and 320 K, with 320 K considered an elevated-temperature stress condition. The findings indicate that the complex containing decasaccharide heparin exhibits the most stable structure and the strongest interaction with the RBD, as evidenced by consistently lower electrostatic and van der Waals energies. Moreover, post-MD MM/PBSA calculations provided relative binding-energy estimates and revealed the energetic contributions of molecular-mechanics, polar-solvation, and nonpolar-solvation terms. These results suggest that the predicted interaction stability of the tethered heparin-RBD complexes arises from the combined effects of electrostatic interactions, solvation contributions, and persistent intermolecular contacts. Overall, the results provide a comparative structural and energetic characterization of three tethered heparin systems and identify the decasaccharide-containing construct as having the most favorable relative interaction energetics among the modeled systems. Experimental validation and matched control simulations will be required to determine biological relevance and any scaffold-dependent advantage.

To develop low-cost, high-performance catalysts for low-temperature carbon monoxide (CO) oxidation, a low-crystallinity calcite-type CaCO3 support was prepared by calcining calcium citrate at 500 ℃. Pd based catalysts with Pd loadings of 0.2-2 wt.% over the obtained CaCO3 supports were synthesized via excess impregnation, using palladium acetate as the precursor and acetone as the solvent. The Pd/CaCO3 catalysts were systematically characterized by XRD, N2 adsorption-desorption, TEM, EDS and XPS, and their low-temperature CO oxidation performance was evaluated. All catalysts exhibit mesoporous features with Type Ⅳ isotherms and Type H3 hysteresis loops, and 0.5Pd/CaCO3 displays the optimal specific surface area, pore volume and pore size.The average Pd particle size increases from 1.86 nm to 4.23 nm with rising Pd loading, and 0.5Pd/CaCO3 possesses highly dispersed ultrafine Pd particles of 2.21 nm. The control sample 0.5Pd/precipitated CaCO3 has a T100 of 130 ℃, while 0.5Pd/CaCO3 achieves complete CO conversion at 120 ℃ and retains stable conversion over 120 h of continuous testing, verifying the advantage of the self-made support. The better performance for calcining samples arises from the synergistic effect of Pd[0] and Pd[2+], 2 highly dispersed Pd nanoparticles, a developed mesoporous structure and the defect anchoring effect. This study provides a scalable, low-cost and efficient Pd-based catalytic approach for low-temperature CO oxidation.

As an effective tool to monitor the glucose level in the human body and to diagnose diabetes, glucose sensors are widely applied in medical practice and the daily life of patients. Cupric oxide (CuO) is a promising material for fabricating non-enzymatic glucose sensors. While CuO shows very good sensing performance and is easy to synthesise, the common wet chemical routes can result in varying nanostructures depending on various parameters, including temperature and pH. The present work explores the influence of the solution pH and base/acid addition order on the physico-chemical characteristics and sensing behaviour of CuO formed following a simple solution synthesis route. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Raman and IR spectroscopy were used to characterise the nanostructures. Although the synthesis route is robust with respect to the acid/base concentration, it is clear that an overall alkaline environment is needed for the successful formation of CuO nanostructures.

The size-dependent exchange-bias in Py/Ir23Mn77(IrMn) magnetic nanocaps was investigated. The magnetic cap structures were fabricated by depositing magnetic thin films of layer stack Py (40 nm)/Ir23Mn77(t= 3 nm, 5 nm, 7 nm)/Pt (5 nm) onto large, closely packed arrays of polystyrene spheres with diameters of 175 nm, 607 nm, and 1020 nm. By zero-field cooling below the blocking temperature of the antiferromagnetic IrMn grains, the spin structure of the Py layer is imprinted into the IrMn, which manifests as an increase in the vortex nucleation and annihilation fields. Under field cooling, either a displaced vortex state or a C-state can be stabilized. Furthermore, we investigated the distribution of blocking temperatures across the Py/IrMn sample series. Blocking temperature measurements indicated a distribution of IrMn grain stabilities, where the mean blocking temperature was found to increase with IrMn thickness but decrease with increasing nanocap diameter. This study demonstrates that the exchange bias in Py/IrMn magnetic vortex caps can be effectively tailored by varying the diameter of the cap structures and the thickness of the IrMn layer.

Driven by the globalization policy to cut greenhouse gas emissions from fossil fuels and the urgent need of clean energy, lithium-ion batteries (LIBs) have been continuously pushed toward higher energy density. In this pursuit, transition metal sulfides (TMSs) stand out for their high storage capacity, yet their intrinsic limitations on large volumetric strain and poor electric transport impede their adoption in commercial batteries. This review focuses on three earth-abundant TMS families (copper, zinc and manganese sulfides), and systematically evaluates the modification strategies developed over the past few years. Carbon-confined architectures such as core-shell, MXene hybrids and heteroatom-doped frameworks, consistently reliably stabilizes cycling across all three materials, and heterointerface engineering markedly boosts rate capability especially for zinc sulfides. Defect control through sulfur vacancies just opens a pathway to raise native conductivity, though it remains at an early stage of development. Apart from multi-strategy combinations, this review also surveys ternary/quaternary chalcogenides (e.g. Cu2ZnSnS4) and binder-free electrode fabrication including flame spray pyrolysis and direct growth on current collectors as emerging directions. Despite it is still existing hurdles like low initial Coulombic efficiency, unclear phase transition mechanisms and gap between lab and practical applications, design principles drawn from these three sulfides provide an adaptable blueprint to develop high-performance, cost-effective conversion anodes for next-generation LIBs.

This work demonstrates that mechanical exfoliation induces measurable distortions in the van der Waals (vdW) gap of layered crystals, while the annealing process can reduce this distortion. Using X-ray diffraction (XRD), lattice parameters were compared in bulk and mechanically exfoliated flakes of selected transition metal dichalcogenides and monochalcogenides. The results reveal a systematic expansion of the lattice parameter along the [00.1] direction (perpendicular to the vdW layers) in the exfoliated samples, corresponding to residual strain values from 0.037% for GeS to 0.39% for ZrS2. This suggests that exfoliation introduces residual structural strain into the crystal lattice. In contrast, optical measurements indicate that these lattice modifications have only a minor effect on the electronic band structure, as the energies of optical transitions do not change significantly. This observation is consistent with density functional theory (DFT) calculations, which show that although the lattice expands predominantly along the [00.1] direction compared to [10.0], the corresponding changes in band gap are small. The results highlight that residual strain is a consequence of mechanical exfoliation and likely a universal feature of two-dimensional layered materials. Ab initio calculations confirm that the vdW gap in mechanically exfoliated multilayer flakes is enlarged by 0.04-0.19% compared with bulk crystals. This observation is important for accurate modelling of heterostructures composed of mechanically exfoliated van der Waals crystals.

Predictive domain wall nucleation, propagation, and pinning is achieved by He[+] ion irradiation of spin-orbit torque thin film devices. Engineering the magnetic anisotropy landscape with nm precision, we demonstrate that non-irradiated gaps as small as 10 nm can act as reliable pinning sites, highlighting the potential of this method for device miniaturization. We also create artificial nucleation centers, enabling deterministic control of the switching process and subsequent reversal propagation. This study presents a simple and effective strategy for advancing nanoscale design of energy-efficient domain wall memory and logic devices.

Gallium oxide (Ga2O3) nanoparticles were synthesised via forced hydrolysis, employing a range of annealing temperatures from room temperature (24 °C) to 900 °C for pH starting conditions 7.5 and 9.5. The crystal phase was controlled using annealing treatment, and monitored using Raman spectroscopy, and the optical bandgap and luminescence were systematically investigated using UV‑vis spectrophotometry and cathodoluminescence. GaO(OH) formed between room temperature (24 °C) and 300 °C, with optimal crystal quality observed at 200-300 °C. Meanwhile α‑Ga2O3 emerged between 300 °C and 600 °C, peaking in quality at 500 °C, and β‑Ga2O3 was produced between 600 °C and 900 °C, with the highest quality achieved at 900 °C. A proof‑of‑concept UV photodetector demonstrated a responsivity of 72.1 μA/W at 250 nm, a photo‑to‑dark current ratio of 122, and a 250 nm/375 nm rejection ratio of 67. These results underscore the potential of this low‑cost synthesis route for UV detection and UV‑assisted gas sensing applications.

This work demonstrates a high-performance N-polar GaN/AlGaN metal-oxide-semiconductor high-electron-mobility transistor (MOSHEMT) fabricated via a thin-layer transfer technique. By transferring Ga-polar AlGaN/GaN epitaxial layers grown on a Si (111) substrate to a Si (100) substrate using surface activated bonding and Si substate removing techniques, high quality N-polar heterostructures on Si were achieved, which bypasses the direct N-polar epitaxial growth challenges. The fabricated N-polar MOSHEMT with 10 nm HfO2 gate dielectric and a 100 nm gate length exhibits a maximum drain current (Idmax) of 1.1 A/mm, an on-resistance (Ron) of 3.8 Ω·mm, a peak transconductance (gmmax) of 125 mS/mm, and a cutoff frequency/maximum oscillation frequency (fT/fmax) of 29/40 GHz. This approach enables N-polar GaN integration with cost-effective Si platforms, offering a scalable pathway for high-speed, high-power mm-wave applications.

Terahertz radiation sources based on the intrinsic Josephson junctions in the high-temperature superconductor Bi2Sr2CaCu2O8+δ(BSCCO) hold significant promise for applications in spectroscopy, imaging, and communications. However, the performance of these devices is often influenced by non-ideal material properties, particularly surface degradation arising from oxygen loss during fabrication. In this work, we investigate the origin of an experimentally observed excess voltage,Ve, defined as the deviation of the applied bias voltage from the value expected based on the ac Josephson relation and the measured emission frequency. This excess voltage indicates that a fraction of the intrinsic junctions within the stack do not actively contribute to coherent terahertz radiation. We hypothesize that this discrepancy stems from a thin, non-superconducting degradation layer on the BSCCO crystal surfaces and develop a three-dimensional coupled electro-thermal finite element model to test this hypothesis. By explicitly incorporating a resistive surface layer with modified electrical properties, our simulations reproduce the measured current-voltage characteristics across a temperature range of 30-70 K with significantly improved accuracy compared to models assuming a homogeneous stack. Both experimental data and numerical results reveal thatVeexhibits a non-monotonic dependence on bias current and decreases with increasing temperature, a behavior linked to the evolving thermal profile and hot spot formation within the device. Based on the quantitative agreement between simulation and experiment, we estimate the thickness of the degradation layer to be on the order of 5-10 nm. Our findings provide a consistent explanation for the excess voltage phenomenon and highlight the critical role of surface stoichiometry in governing the electrical and radiative performance of BSCCO terahertz emitters. This work offers essential insights for the accurate modeling and future optimization of superconducting terahertz sources.

Colloidal lead sulfide (PbS) nanocrystals (NCs) are emerging as cost-effective, solution-processable materials for infrared (IR) detection. Their use in a space environment is conditioned by their radiation tolerance. This study investigates the intrinsic robustness of PbS NC-based photoconductive devices to high-dose X-ray irradiation (up to 1.6 Grad [PbS]), far above requirement for deep-space operation. PbS NC films exhibit gradual performance degradation without abrupt thresholds, attributed to their polycrystalline nature, which localizes defects and mitigates long-range lattice disruption. Optoelectronic measurements reveal a drop in both the dark and illuminated response, yet the signal-to-noise ratio improves due to the faster decay of dark current. Spectroscopic analyses (XPS/HAXPES) confirm that the conductivity change can be attributed to X-ray-induced oxidation, which affects both Pb and S, forming sulfate and lead hydroxide phases that propagate throughout the NC volume. This oxidation reduces the effective NC size, blue-shifting the excitonic peak. Despite this, PbS NCs exhibit exceptional radiation hardness, comparable to that of radiation-hardened CMOS devices. These findings position PbS NCs as viable candidates for space-born IR detection, especially in oxygen-free environments where oxidation is naturally limited.

While traditional hydrogen peroxide detection methods each have their own advantages in different application scenarios, some methods still suffer from issues such as insufficient sensitivity, limited specificity, complex procedures, or poor resistance to interference. In this study, we developed an Au@Ag core-shell surface-enhanced Raman spectroscopy (SERS) nanoprobe incorporating the Raman-reporting molecule 5,5'-Disulfanediylbis(2-nitrobenzoic acid), for the highly sensitive and specific quantitative detection of H2O2. Gold nanoparticles were prepared using the sodium citrate reduction method, and Au@DTNB@Ag nanoprobes were synthesized via the seed-growth method. The structures were systematically characterized using transmission electron microscopy, zeta potential measurements, and Raman spectroscopy. By combining finite element simulations with density functional theory calculations, we have elucidated the SERS enhancement mechanism underlying the synergistic interaction between electromagnetic and chemical enhancement in this nanoprobe; based on the concentration-dependent oxidative etching effect of H2O2 on silver shells, a quantitative SERS detection method for H2O2 using the nanoprobes was established, and systematic methodological validation was completed. The results indicate that the prepared Au@DTNB@Ag nanoprobes possess a uniform core-shell structure and excellent SERS activity. The characteristic Raman peak of DTNB at 1294 cm[-1] was selected as the quantitative analysis signal. Within a concentration range of 0.12 μM to 29.4 μM, a good dose-response relationship was observed between H2O2 concentration and Raman signal intensity. Fitting with a four-parameter logistic model yielded a calibration curve R[2] of 0.99915. The detection stability was excellent, coefficients of variation for measured concentrations at medium and high concentration levels were all below 10%, and the spike recoveries met the acceptable standards for trace analysis. The detection method developed in this study is simple to operate and provides rapid results. It demonstrates certain advantages in terms of sensitivity and resistance to interference, offering a new technical option for the quantitative detection of H2O2 in complex matrix samples in the food, environmental, and biological sectors.

Carbohydrates play critical roles in all living systems, serving as structural components and energy sources, and mediating cell-cell recognition. Inspired by the multivalent display of glycans on cell surfaces, synthetic glyconanomaterials have been developed where multivalent ligand presentation leads to significantly enhanced binding affinity towards carbohydrate-binding proteins, i.e., lectins, and have been used in applications such as biosensing, imaging, targeted drug delivery, and diagnostics. One of the key parameters governing glyconanomaterial-lectin interactions is the carbohydrate density on glyconanomaterials, which dictates the binding affinity with lectins. Accurate quantification of ligand density is therefore essential for establishing meaningful structure-property relationships. This review summarizes common analytical methods used to quantify carbohydrate density on glyconanomaterials, including colorimetric assays, thermogravimetric analysis (TGA), nuclear magnetic resonance (NMR) spectroscopy, and cleavable probe-based approaches. For each method, the underlying principles, experimental considerations, and limitations are discussed. Representative literature examples are highlighted to show the influence of nanoparticle composition, size, and conjugation chemistry on reported ligand density values. Future efforts include developing standardized protocols and reference materials to ensure accurate and reproducible results.

Ammonia (NH3) gas sensors play an essential role in agricultural production, industrial manufacturing, human health protection and environmental monitoring. However, development of the room-temperature NH3-sensing materials with sensitive response remains challenging. In this work, SnS2/Ti3C2Tx composites with S vacancies are prepared by the hydrothermal process in which the introduction of a high concentration of CH4N2S promotes the formation of S vacancies. Compared with SnS2, the optimized SnS2-Ti3C2Tx composites exhibit a response of 71.5% to 300 ppm NH3, enhancement of 90%, as well as excellent reproducibility, long-term stability, and selectivity. During NH3 sensing, SnS2 with S vacancies not only provides more active sites for NH3 adsorption but also exhibits a modified electronic structure of SnS2 with improved NH3 adsorption. Ti3C2Tx, with high electrical conductivity, provides electron-transfer channels. The interfacial heterojunction facilitates charge transport and provides abundant active sites for NH3 adsorption. The results suggest significant potential for designing two-dimensional materials with tunable sensing properties through defect and heterojunction engineering.