Search Results (268)

We investigate the formation of surface periodic structures during ablation of a 20 nm aluminum film on a glass substrate by high-power terahertz pulses. Using subpicosecond pulses in the 0.5–3 THz range with a field strength of 15 MV/cm (fluence 0.3 J/cm²) generated in a DSTMS crystal pumped by a femtosecond Cr:Forsterite laser, we observe discrete growth of cone-shaped damage channels with a period of 20 µm at an energy density below the single pulse ablation threshold ($F_a\approx 0.15$ J/cm²). The channel length increases from pulse to pulse (for 8, 20, and 100 pulses) due to local current density enhancement at the channel tip. This enhancement scales inversely with the square root of the tip radius and reaches an order of magnitude. Surface morphology analysis reveals a thermomechanical mechanism governing film destruction. The observed self-organized periodic structures, whose orientation is strictly perpendicular to the THz electric field, hold promise for functional devices in the terahertz band, such as polarizers, near-field sensors, and spatially selective absorbers, provided the formation process can be regulated. Full article

Nanoporous films assembled by low-kinetic-energy deposition of individual nanoparticles are complex nanomaterials for a variety of applications, from gas sensing to neuromorphic computing. We develop a numerical strategy for assembling metallic nanoparticles into 25–40 nm thick films from an arbitrary distribution of Au nanoparticles in terms of their initial size and shape. We characterize the structural properties of the assembled films as a function of the initial nanoparticle distribution. The morphology of the deposited nanoparticles affects nanofilm thickness, porosity, and its internal structure, including the length, type, and density of dislocations. Film porosity and the average dislocation length mainly correlate with the size of deposited nanoparticles. At the same time, thickness and dislocation density can also be affected by the shape of the larger nanoparticles deposited. Full article

Large-area MoS₂ nanotube arrays were successfully prepared using a combination of simple and reliable electrochemical deposition and chemical etching techniques, with highly ordered ZnO nanorod arrays used as the template. The thickness of MoS₂ nanotube walls can be effectively controlled by adjusting the deposition time. The characterization results of SEM and TEM showed the successful preparation of MoS₂ nanotube arrays with different wall thicknesses. The composition of the obtained nanotube arrays was verified to be MoS₂ by EDS, XRD, and XPS characterizations. It is worth noting that compared to MoS₂ nanofilms, the as-prepared MoS₂ nanotube arrays exhibit stronger photoelectric response properties; the on/off ratio and photoresponsivity increased by 2.8 times and 3.8 times, respectively, mainly attributed to its significantly increased specific surface area. These research results provide new ideas for the large-area controllable preparation of MoS₂ low-dimensional nanostructures, as well as new material candidates for the development of low-cost and high-performance photodetectors. Full article

The precise spatiotemporal monitoring of dopamine is critical for understanding neurotransmission and neurodegenerative pathologies. While traditional electrochemical methods offer excellent temporal resolution, they lack the spatial resolution required to map network-wide dynamic events. To address this, we adapted a wide-field plasmonic electrochemical microscopy (PEM) platform to spatially image localized electrochemical reactions. Specifically, we leveraged the anodic electropolymerization of dopamine into a surface-confined polydopamine nanofilm to enable label-free, pixel-level optical quantification. Bulk solution testing demonstrated highly uniform sensor sensitivity, yielding an estimated single-pixel limit of detection of 14 pM. Furthermore, utilizing a custom injection system, we successfully imaged the real-time localized delivery of micromolar dopamine concentrations and demonstrated qualitative responsiveness of the integrated optical signal to delivered dopamine as a proof-of-concept for the platform. The platform functions as a spatially resolved mass integrator while simultaneously decoupling this chemical signal from transient hydrodynamic mechanical deformations caused by dopamine injection flow. Ultimately, this platform establishes the fundamental methodology required for future high-throughput spatial monitoring of complex neurotransmitter release dynamics across cellular networks. Full article

Pancreatic ductal adenocarcinoma (PDAC) is the most aggressive malignancy, characterized by rapid progression, early metastasis, and resistance to conventional therapies. Increasing evidence indicates that the behavior of residual tumor cells is strongly influenced by physicochemical properties of their microenvironment. Surface engineering strategies using nanostructured materials may therefore represent a complementary approach to modulating cancer cell activity. In this study, we investigated whether a graphene oxide (GO) aerosol nanofilm modifies the biological behavior of PDAC cells in vitro. The GO aerosol (4.5 g/L) was characterized using STEM, DLS, zeta potential measurements, LIBS, EDX, and FTIR spectroscopy. Ultrastructural analysis revealed thin, wrinkled GO sheets forming partially overlapping lamellar structures, while physicochemical characterization confirmed a highly oxidized stable nanomaterial. Human PDAC cell lines (BxPC-3 and AsPC-1) were cultured on GO-modified substrates to assess morphology (SEM), metabolic activity (XTT assay), migratory capacity (wound healing assay over 72 h), and expression of genes related to proliferation and epithelial–mesenchymal transition (EMT) by RT-qPCR. GO nanofilm significantly reduced cell viability and inhibited migration in both cell lines. SEM analysis demonstrated shortened cytoplasmic projections and altered membrane integrity. Gene expression profiling revealed cell line-dependent transcriptional responses, including modulation of components of the PI3K/AKT/mTOR pathway and EMT-associated markers. Collectively, our findings demonstrate that GO aerosol nanofilm alters PDAC cell morphology, viability, and migratory behavior in vitro. Surface-mediated modulation of tumor cell activity may represent a promising adjunct strategy for limiting residual cancer cell survival and metastatic potential. Full article

Quantitative detection of alkaline phosphatase (ALP) activity is crucial in clinical diagnosis and bioanalysis. Herein, we have developed a highly sensitive electrochemiluminescence (ECL) biosensor that employs a biomimetic zirconia interface as its core sensing platform. The interface was constructed by immobilizing o-phosphorylethanolamine (PEA) onto zirconium oxide nanofilms (ZrO₂NFs), forming a surface rich in Zr-O-P bonds. This design mimics phosphate recognition and enzyme-triggered dephosphorylation processes, where ALP catalyzes the hydrolysis of these bonds, triggering a direct switch in the ECL signal from Ru(bpy)₃²⁺-loaded gold nanocage (Ru-AuNCs) emitters. This sensor achieves a wide linear range of 0.100–100 U/L and a low detection limit down to 0.0899 U/L. Its practical utility was validated through the accurate detection of ALP in fetal bovine serum samples, confirming high recovery and reliability. This strategy highlights the potential of biomimetic zirconia interfaces in developing robust biosensors for early disease diagnosis. Full article

A bidirectional infrared absorber leveraging the Fabry–Perot resonance within a cascaded metal-dielectric nano-film structure is proposed. The absorber integrates a top Ag–VO₂–SiO₂ film stack, an intermediate thin Ag metal layer, and a bottom Al₂O₃–Ti–Al₂O₃ layer, enabling switchable narrowband and broadband absorption under forward and backward illumination, respectively. Under front illumination, the structure exhibits a high narrowband absorption peak of 98% at a wavelength of 1110 nm when VO₂ is in its metallic state. In contrast, when VO₂ transitions to its insulating state, the absorption peak shifts to 1165 nm. Additionally, under back illumination, ultra-broadband absorption is achieved, covering a wavelength range of 1000–2760 nm with an average absorption of 98%. The proposed absorber demonstrates excellent absorption performance with structural simplicity and low manufacturing cost, offering great potential for applications in solar photovoltaic devices, photodetectors, and related fields. Full article

Piezoelectric actuators are essential for sub-millimeter robots and reconfigurable microstructures owing to their advantages, including the ability to operate in air and high-speed response. However, the substantial performance degradation observed in piezoelectric actuators with sub-micrometer thickness poses a critical challenge for the design of low-voltage microactuators capable of achieving large bending curvature. Here we develop a coupled analytical–numerical framework for designing multilayer lead zirconate titanate (PZT) nanofilm microactuators under a low voltage constraint (≤5 V). An analytical multilayer beam model is extended to incorporate thickness-dependent material properties and an interfacial dead layer that reduces the effective electric field at small thicknesses. This enables rapid exploration of curvature and the neutral-axis position as functions of the thicknesses of PZT, electrodes, and the dielectric layer. Two- and three-dimensional finite-element simulations provide complementary predictions of neutral-axis location, voltage-dependent curvature response, and eigenmode shapes. The resulting design maps reveal a non-monotonic optimum for PZT thickness in the few-hundred-nanometer range to maximize the curvature change at low voltages and identify ultrathin top electrodes as a key design lever that enhances bending by reducing parasitic stiffness while shifting the neutral axis favorably. These findings offer quantitative guidelines for designing low-voltage, high-curvature piezoelectric microactuators for microrobotic systems. Full article

The current research investigates the electrochemical performance of plasticized nanocomposite solid polymer electrolytes derived from a polyethylene oxide (PEO)–polymethyl methacrylate (PMMA) blended system with lithium iodide (LiI) as the dopant salt and tin dioxide (SnO₂) nanoparticles as the inorganic nanofillers. Thin nanofilms of the synthesized electrolytes were prepared and progressively examined by using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), Ultraviolet visible (UV–Vis) spectroscopy, and Scanning electron microscopy (SEM). XRD characterization confirmed the successful establishment of the polymer electrolyte matrix and reflected a significant decrease in crystallinity upon the incorporation of nanofillers, whereas crystallite size was estimated using the Debye–Scherrer equation. FT-IR spectra showed prominent molecular interactions and complexation of polymer, salt, and nanofiller components. UV–Vis spectroscopy provides information on the optical absorption behavior, whereas the SEM micrograph shows the morphological features and homogeneity of plasticized nanocomposite solid polymer electrolyte films. The addition of SnO₂ nanofillers was shown to improve both the structural and electrochemical properties of the electrolyte system, highlighting its potential usage in solid-state batteries and other high-end electrochemical devices. These enhancements make the developed nanocomposite solid polymer electrolytes viable candidates for high-performance, flexible lithium-ion battery applications, offering a promising route toward safer and more efficient energy storage systems. Comprehensive electrochemical performance evaluation will be addressed in future studies. Full article

Magnetic-field-assisted electrocatalysis offers a powerful route to enhance the oxygen evolution reaction (OER) by coupling spin-dependent effects with magnetohydrodynamic phenomena. Here, we present a unified study of cobalt ferrite (CoFe₂O₄)-based nanofilms, elucidating the combined roles of rare-earth doping, nanoparticle size, film morphology, and electrode substrate magnetism on OER performance under external magnetic fields. The effect of UV-light irradiation is also investigated. CoFe₂O₄ and yttrium-doped CoFe₂O₄ nanoparticles were synthesized via thermal decomposition and self-combustion routes, yielding single-domain particles with distinct structural and magnetic properties, and assembled into homogeneous nanofilms using the Langmuir–Blodgett technique. Electrocatalytic measurements in alkaline media reveal that intrinsic OER activity is primarily governed by film compactness and charge-transfer efficiency, while the magnitude of magnetic-field-induced enhancement depends on the magnetic response of both the nanofilms and the supporting electrode. Ferromagnetic substrates promote enhanced catalytic activity under magnetic fields, whereas diamagnetic substrates can exhibit suppressed performance. Across all systems, the strongest enhancement is observed when the magnetic field is applied parallel to the electrode surface, reflecting the combined effects of spin polarization and Lorentz-force-driven mass transport. UV-light irradiation is also evaluated as an external stimulus to promote the reaction. Our findings establish a comprehensive framework for designing magnetically assisted OER electrocatalysts and demonstrate that magnetic-field effects can rival or complement rare-earth doping or UV-light irradiation, offering a sustainable pathway toward high-efficiency water oxidation. Full article

This study addresses the challenges of large-scale processing and resource utilization of mango waste in the Panzhihua region. Its focus is on investigating the key role of material ratio optimization in improving the humification quality of compost products. Three typical wet weight ratios of discarded mango and pruning branches were used (T1, T2, T3) toconduct high-temperature aerobic composting experiments under the stable environmental conditions provided by nanomembrane coverage. The temperature of the compost pile, nitrogen transformation, and dynamic changes in humic components were systematically monitored. The results showed that the T2 treatment achieved the optimal compost performance, entering the high-temperature period (≥55 °C) within 4 days, with a peak temperature of 61.9 °C, and the high temperature lasting for 13 days. The carbon-nitrogen ratio decreased by 46.6%, and the ammonia volatilization rate was the lowest (0.0135 mg/(m²·d)); the degree of humification was the highest, with the HA/FA ratio reaching 2.19 and the seed germination index being 222.49%. This study demonstrates that an appropriate “fruit-to-branch” ratio, under the stable environment created by nanomembrane coverage, can synergistically promote the compost humification process and product quality. This provides a reliable theoretical basis and technical pathway for the resource utilization of mango waste. Full article

Phase-change materials of the Ge–Sb–Te (GST) system are promising for non-volatile memory and programmable photonics owing to their reversible amorphous–crystalline transitions. Among these materials, GeSb₄Te₇ stands out for its optimal balance of thermal stability, switching speed, and energy efficiency. The properties of GST materials are critically dependent on structural defects, particularly germanium vacancies that occur during synthesis and operation. Using density functional theory, we demonstrate that Ge vacancies and Ge–Sb intermixing significantly influence the electronic and optical properties of GeSb₄Te₇. Positive binding energies reveal vacancy clustering tendencies, which systematically reduce p-type degeneracy and widen the band gap (from 0.47 to 0.67 eV at a 2.7% vacancy concentration). Consequently, the metallic optical response in the visible range diminishes, as reflected in the less negative real dielectric function. Furthermore, we extend our investigation to the fundamental building block of this material system, the GeSb₂Te₄ monolayer. By studying controlled interlayer displacements of Ge and Te atoms in an otherwise stoichiometric slab, we elucidate the switching mechanism in the two-dimensional limit. The pristine monolayer exhibits semiconducting behavior with an indirect band gap of 0.74 eV, while layer sliding induces a semiconductor-to-metal transition accompanied by pronounced changes in the optical absorption spectrum. The asymmetric energy barrier (1.69 eV forward, 0.60 eV reverse) suggests favorable reversible switching via structural distortions alone, without requiring chemical modifications. The obtained results, spanning from defective bulk crystals to structurally distorted monolayers, are important for the targeted optimization of GST material properties in memory devices, optical elements, and emerging nanoscale phase-change applications. Full article

Aniline (ANI) was electropolymerized on ITO substrates with different surface resistivities. The process was performed by cyclic voltammetry from an aqueous, homogeneous solution containing sulfuric acid and the aniline monomer using various numbers of cycles and scan rates. The resulting polymer films (PANI) were characterized by ATR-IR spectroscopy, spectroscopic ellipsometry and atomic force microscopy. The influence of ITO surface resistivity on the electropolymerization process, the quality of the obtained PANI layers, and their optical properties was evaluated. Homogeneous PANI films were produced on ITO substrates with surface resistivities of 15–25 Ω/sq, encompassing both emeraldine salt and emeraldine base forms. Although the film’s growth was rapid, it also led to adhesion issues. In contrast, for ITO substrates with surface resistivities of 70–100 Ω/sq and 80–100 Ω/sq, the resulting films showed improved adhesion but were less homogeneous. Nevertheless, the conductive emeraldine salt form of polyaniline was successfully obtained. The conductive form of polyaniline was obtained without any additional modifications to the electropolymerization procedure. Notably, the literature provides no systematic analysis of electropolymerization on ITO substrates with different surface resistivities, which opens up new research opportunities and provides a basis for the rational design and optimization of PANI-based electro-optical coatings for advanced sensing applications. Full article

Despite efforts to produce scalable, substrate-independent, low-defect-density, and high-quality MoS₂, this continues to be a critical challenge for industrial-scale applications. This work aims to present a chemical vapor deposition (CVD) method for growing high-quality and potentially large-area mono- to few-layer MoS₂ films via proximity between the Mo nanofilm substrate and the target substrates. By using stoichiometry-guided knowledge of Mo-S and Mo-O-S phase diagrams, Mo nanofilms are oxidized and then sulfurized under optimized conditions to grow high-quality, millimeter-scale mono- to few-layer MoS₂ films in proximity to the target substrate. We have achieved millimeter-scale continuous growth of MoS₂ revealed via optical microscopy. Two-dimensional Raman maps of Full Width at Half Maximum show high-quality growth, and photoluminescence-based B/A exciton amplitude ratio shows high crystalline and optical quality with low defect density. Full article

Three-dimensional ZnO structures were prepared by both thermal atomic layer deposition (ThALD) and plasma-enhanced atomic layer deposition (PEALD) on a sacrificial cellulose template. The synthetic approach consisted of ALD of conformal ZnO nanofilms on the fibrous cellulose template, followed by thermal removal of the polymer. The resulting calcinated samples, consisting of a scaffold of fused polycrystalline ZnO nanoparticles, showed a sevenfold and ninefold increase in photocatalytic activity against methyl orange under ultraviolet-A light, for the ThALD and PEALD samples, respectively, compared to the non-calcined samples prior to cellulose removal. In addition to the improved three-dimensional surface exposure and accessible active sites, it was suggested that the amount of hydroxyl groups on the surface and the density of nanoparticle packing in 3D ZnO structures are critical parameters for improving the photoinduced degradation of the dye. Full article