Applied Physics A最新文献

Photocatalytic purification represents a cornerstone in next-generation clean energy and environmental technologies.The use of heterostructures improves photocatalytic activity. In this work, Zn_0.92 Co_0.08O/ Mo_0.92 Mg_0.08S₂ nanocomposite (CZ-MM) has been synthesized by hydrothermal method. The purpose of this research is to investigate the performance of this nanocomposite for the degradation of the dye methylene blue (MB). Unlike conventional ZnO/MoS₂ or Co–ZnO systems, this material exploits a synergistic dual-doping mechanism, where Co and Mg dopants modulate band structures and create interfacial charge-bridging states. Properties of samples were investigated using X-ray diffraction (XRD), Raman spectroscopy, FT-IR spectroscopy, scanning electron microscopy (SEM) and Field Emission Scanning Electron Microscopy (FESEM), UV-vis diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL) and Brunauer-Emmett-Teller method (BET). The photocatalytic performance of Zn_0.92 Co_0.08O, Mo_0.92 Mg_0.08S₂ and prepared nanocomposites were compared for the degradation of MB dye under visible light irradiation. The highest degradation rate of MB by CZ-MM nanocomposites was about 89% in 120 min, which is significantly higher than the efficiency of Zn_0.92 Co_0.08O (26%) and Mo_0.92 Mg_0.08S₂ (44%). The improvement of photocatalytic performance in nanocomposite is attributed to the synergistic effect of Zn_0.92 Co_0.08O and Mo_0.92 Mg_0.08S₂. The results of BET analysis showed that CZ-MM nanocomposite (12.52 m²/g) has a larger surface area than doped MoS₂ (8.49 m²/g). Based on the obtained results, the composite that contained more Mg-doped MoS₂ had better performance. From a visionary perspective, this approach could lay the foundation for self-regulating photocatalytic surfaces – materials that dynamically adapt their charge landscape, much like autonomous systems in advanced robotics or AI-driven energy platforms. In essence, this work not only optimises photocatalysis but also redefines our understanding of light–matter interactions at the nanoscale a concept that could have as profound an impact on next-generation clean-tech industries as reusable rockets have had on aerospace.

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Laser ablation for creating microstructures on diamond surfaces serves as an effective strategy to address the heat dissipation issues in high-heat-flux electronic devices. Achieving uniform ablation on diamond surfaces is crucial for fabricating such microstructures. This study employs a low-cost laser processing technique combined with CNC software to fabricate high-precision microstructures with limited heat-affected zones on polycrystalline diamond surfaces. The ablation mechanisms and quantitative material removal of three differently oriented single-crystal diamonds were characterized using confocal laser scanning microscopy and molecular dynamics simulations. Results indicate that the (111)-oriented single-crystal diamond exhibits the highest removal volume of 1.0 × 10¹⁵ nm³, followed by the (110) orientation with 7.5 × 10¹⁴ nm³, and the (100) orientation with the smallest removal volume of only 6.2 × 10¹⁴ nm³. Additionally, the grain orientation of polycrystalline diamond and the morphological evolution after ablation were investigated using Raman spectroscopy, electron backscatter diffraction, and atomic force microscopy. The removal volume follows the order of (111) >(110) >(100), which is consistent with the experimental results from single-crystal diamonds. Based on these findings, a laser processing strategy was developed by pre-characterizing grain orientations and adjusting laser energy via CNC programming to compensate for removal volume differences caused by crystallographic orientations. This method effectively suppresses “over-ablation” and “non-uniform ablation,” thereby improving the surface flatness of the processed areas. This study not only deepens the understanding of the laser ablation mechanism on diamond but also provides a feasible solution for high-quality and high-precision micro-processing of diamond.

BiFeO₃ (BFO) and GdFeO₃ (GFO) are perovskite structured materials with rich physical properties. This work investigates the influence of annealing temperature (450, 550 and 600 °C) and the use of GFO buffer layer on the microstructural, optical and magnetic properties of BFO/GFO films synthesized by sol-gel spin-coating technique. The films were compared with that of BFO film annealed at 550 °C. From X-ray diffraction analysis, the introduction of GFO layer reduced the lattice parameters and enhanced the crystallinity, purity and particle growth of BFO layer. From atomic force microscopy analysis, the surface of BFO/GFO film annealed at 550 °C showed better particle shape uniformity and less porosity in comparing with BFO film. As the annealing temperature increased from 450 to 600 °C, the energy band gap (E_g) reduced from 2.73 to 2.64 eV. The E_g reduced from 2.71 eV for BFO film to 2.68 eV for BFO/GFO film. Intensity of photoluminescence peaks of the BFO/GFO film increased with the increasing of annealing temperature and with the introduction of GFO layer. The annealing temperature increasing led to enhance the BFO/GFO film magnetization (M_s). However, the BFO/GFO film exhibited a lower M_s 28.2 emu/cm³ compared to BFO film with M_s 29.6 emu/cm³.

A series of deep reddish - orange emitting Sm³⁺ - activated Ca₈ZnGd(VO₄)₇ nanophosphors has been successfully produced using the solution combustion technique. Through X-ray diffraction patterns (XRD), the structural properties of the produced nanomaterials are examined. Crystallisation in the trigonal lattice with space group as R3c (161) is confirmed by the Rietveld refinement technique. The morphological and elemental characteristics of the nanomaterials have been thoroughly characterised using SEM, TEM (scanning and transmission electron microscope) and EDAX (energy dispersive X-ray analysis). The Ca₈ZnGd_1 − x(VO₄)₇:xSm³⁺ (x = 5 mol %) samples exhibited a noticeable emission peak at 704 nm when excited at 408 nm. A doping concentration of 5 mol % was determined to be optimal. The Inokuti-Hirayama model and Dexter’s theory were used to validate the dipole-dipole type of interlinkages as a genuine phenomenon for concentration quenching. Quantum efficiency (85.14%), non-radiative rate (211.2 s^− 1), and radiative lifetime (0.7032 ms) are computed. The Commission Internationale de I’Éclairage (CIE) chromaticity coordinates indicated that the phosphor materials exhibited a high level of colour purity (92.39%). Additionally, the latent fingerprint (LFP) images stained with the produced nanophosphor exhibit outstanding visualization capabilities on numerous surfaces. According to these findings, fabricated nanophosphors have the potential to be useful for white LED applications and LFP identification.

Inspired by the pitcher plant’s needle-like surface, a novel open microchannel architecture with a positively curved base is proposed, creating a wedge-shaped sidewall-base interface that enhances capillary-driven fluid spreading speed and coverage. The arched substrate amplifies solid-liquid contact area, stabilizes wetting pathways, and intensifies capillary forces, enabling precise fluid transport without external power. Experiments and simulations demonstrate that this layered geometry maximizes aerosol contact area in mist-flow collection, boosting droplet capture efficiency by 30% while maintaining stable channel flow. The curved-bottom microchannel offers a bioinspired fluid control solution for microfluidic systems, particularly valuable for miniaturized devices requiring stable flow and efficient mass transfer in environmental monitoring, medical diagnostics, and bioengineering. Its structural innovation provides theoretical foundations and design paradigms for water-harvesting microfluidics.

The magnetic, dielectric and photocatalytic properties of Fe and Ni co-doped Co₃O₄ nanoparticles (NPs) were studied in detail. XRD was done for the phase formation and structural analysis, which confirmed pure spinel phase of Co₃O₄ using Rietveld refinement. The average crystallite size was calculated using refinement data which showed an increase from 16 to 32 nm with co-doping due to increased crystal growth and defects. Surface morphology was studied by using TEM analysis which revealed non-spherical shaped NPs with dense agglomeration having average particles size of 120 nm for undoped and 137 nm for FN44 co-doped, respectively. The increase in average particle size with co-doping is associated with increased crystal growth caused by co-dopants. Magnetic measurements indicate the onset of ferromagnetism (FM) with co-doping which gets strengthen with increasing Fe doping and maximum magnetization was attained for FN62 sample (6% Fe and 2% Ni). The ZFC/FC measurements showed T_N transition at 42 K for undoped NPs which is shifted towards lower temperatures with co-doping. An irreversible ZFC/FC behavior is observed for co-doped samples which also indicates the presence of FM behavior. Photodegradation efficiency was tested using time dependent photodegradation experiment performed against MO-dye, which revealed a rapid and increased degradation efficiency with co-doping attributed to increased charge carrier concentration. FN44 sample (4% Fe and 4% Ni) showed maximum and fast degradation percentage of 89% with 81% degradation in just 30 min, which is attributed to increased electron-hole recombination caused by Fe ions. Frequency-dependent dielectric measurements revealed an abrupt increase in dielectric constant of about 87.6% with co-doping. This is attributed to metallic Fe²⁺ dopant atoms which causes an increase in charge concentration hence, supplying more charges for polarization, furthermore Fe³⁺ and Fe²⁺ ions favored small polaron hopping mechanism. AC conductivity was enhanced to 3.44 × 10^− 7 Sm^− 1 with co-doping as compared to 1.88 × 10^− 8 Sm^− 1 for undoped NPs, due to increased electrical conductivity and grain boundary effects caused by Fe and Ni ions.

In this work, we have synthesized TiO₂ nanograins (NGs) thin films of different thicknesses of 125 nm, 300 nm and 500 nm on glass substrates using DC magnetron sputtering method under optimized conditions. The nitrogen dioxide (NO₂) gas sensing properties can be enhanced by increasing the exposed surface area of active gas sensing element at nanoscale. Due to high surface to volume ratio, nanostructured TiO₂ thin film-based sensing elements revealed high surface area to react with analyte gas molecules. As a result, the surface reactivity is enhanced which caused to improve the gas sensing properties significantly. The NO₂ gas sensing performance along with the sensing mechanism of the developed TiO₂ NGs sensor were discussed in detail under low detection limit (2–50 ppm) at different operating temperatures (25–370 °C). TiO₂ thin film of thickness 300 nm exhibited excellent sensing properties and the sensor response of 21.5% and response/recovery time of (52 s/84 s) were observed to 10 ppm NO₂ in dry synthetic air at 270 °C. Moreover, the selectivity, stability, and reproducibility were also carried out for better device performance. Therefore, the nanostructured thin film based gas sensors paves a new approach to fabricate low cost and high performance gas sensor for detection of trace amount of NO₂ in the environment. 

Graphical Abstract

In this study, the (3+1) dimensional generalized Yu-Toda-Sasa-Fukuyama equation (YTSF) and its relevance to physical and engineering systems are investigated. We apply the newly developed (phi ^6)-model expansion method to reduce the YTSF equation to a set of ordinary differential equations, allowing for the construction of exact analytical solutions. The resulting soliton solutions, expressed in terms of Jacobi elliptic functions, include parabolic dark solitons, shock wave solutions, bell-shaped solitons, W-shaped solitons, U-shaped solitons, and smooth periodic solitons. These solutions are derived using Maple and are graphically illustrated through 2D, 3D, and contour plots with Mathematica. Solitons, known for their ability to retain shape and velocity over long distances, are ideal for data transmission in electric communication systems. To evaluate the robustness of the model, sensitivity analysis is performed, demonstrating how small changes in initial conditions can significantly influence system dynamics. This study is novel in applying the (phi ^6)-model expansion method to the (3+1)-dimensional generalized YTSF equation for the first time, offering a diverse set of new soliton solutions with potential applications in the design and optimization of modern communication systems. It is very helpful for researchers and engineers to create electric communication systems and make better judgments.

Methyl orange (MO) is a common azo dye that harms human health and is used in the food, paper, and textile sectors. MO detection at low levels is crucial. This study used the hydrothermal method to synthesize a manganese dioxide-titanium dioxide nanocomposite (MnO₂-TiO₂). The synthesized nanocomposite was examined using physicochemical methods, including Energy Dispersive X-ray analysis (EDAX), X-ray Diffraction Spectroscopy (XRD), Field Emission Scanning Electron Microscopy (FESEM), X-ray Photoelectron Spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy (FTIR). The cyclic voltammetry (CV) was used to sense the amount of MO dye. The MnO₂-TiO₂ modified graphite electrode (GE) had a superior current response at a pH of 8. For this MnO₂-TiO₂ modified GE, a linear range of 1–5 µM with a correlation coefficient (R²) of 0.97, a detection limit of 1 µM, a quantification limit of 3.5 µM, and a sensitivity of the sensor is 3 µA.µM^− 1.cm^− 2 were obtained. The findings should be viewed as a beginning point for developing a portable device that aids in onsite monitoring.

Ethylene glycol is a volatile organic compound (VOC), poses severe threats to human health. Thus, efficient monitoring of ethylene glycol is crucial. In this study, ZnO microspheres self-assembled from ZnO nanosheets are synthesized via a simple hydrothermal approach with urea as the medium, subsequent doping with noble metal Pt yielded Pt-ZnO nanosheet-like microspheres (Pt-ZnO NSs) for enhanced ethylene glycol sensing. Pt-ZnO NSs sensor exhibits a high response of 310.74 toward 100 ppm ethylene glycol at 210 °C, with response/recovery times of 45 s/14 s. This excellent performance originates primarily from the large specific surface area of Pt-ZnO NSs, which provides abundant adsorption sites for ethylene glycol molecules. Combined with Density functional theory (DFT) calculations, results demonstrate that Pt modification reduces the adsorption energy (-1.46 eV) of ZnO for ethylene glycol, and facilitates charge transfer between ZnO and gas molecules. Overall, these findings highlight the considerable potential of Pt-ZnO NSs for ethylene glycol sensing applications.