Journal of Electronic Materials最新文献

A (Na_1/2Bi_1/2)TiO₃/polyvinylidene fluoride (PVDF) (0-3 type) composite with a volume fraction of 0.25/0.75 was fabricated via the melt-mixing technique, and its temperature-dependent energy harvesting characteristics were investigated using electromagnetic radiation (EMR) as a non-contact measurement technique. X-ray diffraction analysis confirmed the successful formation of (Na_1/2Bi_1/2)TiO₃ (NBT) and its composite with PVDF, whereas scanning electron microscopy revealed that NBT ceramic particles, ranging in size from 0.1 μm to 3 μm, were uniformly dispersed throughout the PVDF matrix. The electric modulus and dielectric studies indicated non-Debye relaxation, with charge transport characterized as a hopping type. As the temperature increased, both EMR and DC voltage exhibited a significant rise up to 90°C and subsequently showed a slight decline. Moreover, an increase in DC voltage (0.098–0.415 V) was observed with higher capacitor values. These findings, along with the apparent porosity (< 2%), low water absorption (< 0.091 wt.%), and tangent loss (~10⁻²) values, suggest the potential for integrating the composite into self-sustaining, low-power electronic systems. Consequently, the 0-3 type 0.25NBT/0.75PVDF composite presents a promising non-lead option for temperature-dependent energy harvesting and sensing/detection applications.

We used density functional theory and Monte Carlo simulations to look into the magnetic, electronic, and magnetocaloric (MC) properties of a half-metallic Co₂NbAl Heusler alloy. Phonon calculations confirmed its dynamical stability. Antisite disorder induced a half-metallic ground state, with a 0.62 eV bandgap in the minority spin channel and metallic behaviour in the majority spin channel. The magnetism primarily originates from Co atoms (1.10 μ_B), with a minor induced moment on Nb atoms (0.06 μ_B), while Al remains non-magnetic, resulting in a total moment of 2.03 μ_B/f.u. This value exceeds the experimentally reported 1.35 μ_B, likely due to A2-type antisite disorder. Monte Carlo simulations estimated the Curie temperature (T_C) at 348 K, closely matching the experimental value of 383 K, while the mean-field approximation significantly overestimated it at 541.8 K. The relative cooling power (RCP), derived from isothermal magnetic entropy changes, was 11.9 J kg⁻¹ at 0–1 T and 114.6 J kg⁻¹ at 0–9 T magnetic field changes, respectively. Co₂NbAl retained its half-metallicity under pressures up to 10 GPa. Beyond 2 GPa, the magnetic moment and magnetic exchange interaction strengths declined significantly, while the energy gap steadily decreased. The magnetic entropy change (–ΔS_m) increased, T_C decreased, and RCP increased nonlinearly. This showed that Co₂NbAl has a pressure-sensitive MC response.

Two-dimensional materials such as MoS₂ have garnered considerable attention as possible anode candidates for next-generation sodium-ion batteries (NIBs), to satisfy the growing need for energy storage devices. In this study, density functional theory (DFT) is used to examine the potential of MoS₂ as an anode material for NIBs. Ab initio molecular dynamics (AIMD) simulations verified the thermal and dynamic stability of pristine MoS₂, demonstrating structural stability in the range of 300–400 K. It was determined that the maximum adsorption energy (E_ad) for the adsorption of eight Na atoms is −12.74 eV. Furthermore, the exothermic adsorption process is confirmed by the formation energy (E_f) of −5.70 eV for eight Na atoms on the MoS₂ monolayer. When a single Na atom is adsorbed, the electronic band structure of pristine MoS₂ rises slightly from 1.73 to 1.75 eV. However, the bandgap shrinks and eventually disappears upon the adsorption of two Na atoms, signifying a shift to metallic behaviour and enhanced electronic conductivity. Its potential for large-scale energy storage devices is further highlighted by its high theoretical capacity of 1339 mAh g⁻¹. The estimated average open-circuit voltage (OCV) of 1.59 V confirms that Na-MoS₂ is a suitable anode material for NIBs. Furthermore, a diffusion barrier of 0.8 eV indicates moderate Na-ion mobility, which is advantageous for real-world battery applications. Overall, MoS₂ is a good option for next-generation NIB technology due to its strong Na–MoS₂ interaction and tunable electronic properties. Therefore, this work lays the groundwork for future research and development of MoS₂-based anode materials.

Silicon/expanded graphite (Si/EG) composites with nano-silicon-to-EG mass ratios of 1:2 (sample 1) and 1:1 (sample 2) were fabricated via freeze-drying and high-temperature vacuum heat treatment. The nano-silicon was loaded onto the surface of expanded graphite (EG) through the organic cracking of carbon. Initial charge capacity values of 922.9 mAh/g and 1269.9 mAh/g were obtained for sample 1 and sample 2, with initial coulombic efficiency of 78.45% and 79.83%, respectively, while the pure nano-silicon sample was only 49.81%. The reversible capacity after 260 cycles for sample 1 and sample 2 was 526.9 mAh/g and 920.8 mAh/g, with capacity retention ratios of 57.09% and 72.51%, respectively. Moreover, the cycling stability of sample 2 was found to be superior to that of sample 1 due to a more uniform distribution of higher silicon loading on the EG surface, which facilitates the formation of a stable solid electrolyte interface (SEI) film rich in LiF components. The incorporation of EG significantly improves the electrical conductivity and rate capability of silicon-based materials. The Si/EG composite demonstrates excellent high-rate charge/discharge ability due to excellent electrochemical kinetic performance. At current density of 1 A/g, the capacity of sample 1 and sample 2 reached 748.7 mAh/g and 1038.7 mAh/g, with capacity retention rates of 79.7% and 80.2%, respectively. Thus, the design of mass ratios for nano-silicon and EG is critical for obtaining a Si/EG composite with excellent cycle stability and high-rate performance.

This study explores the structural, electronic, and opto-magnetic properties of Y_0.25Mn_0.75Fe₂O₄ with Y = Co, Ni, Cr. The lattice parameters were calculated through structural optimizations utilizing functional Perdew–Burke–Ernzerhof–generalized gradient approximation (PBE-GGA), enabling the understanding of the materials’ performance. For spinel ferrite MnFe₂O₄, the electronic structure has been investigated using density functional theory (DFT), DFT + U (Hubbard on-site Coulomb interaction, U) and DFT + U + V (Hubbard U extension that includes inter-site Coulomb interaction, V). The superior accuracy and significant improvements in electronic properties have been demonstrated by DFT + U + V approach in comparison with GGA and DFT + U + V. Therefore, to explore the electronic and magnetic behavior of Y_xMn_1−xFe₂O₄, a DFT + U + V framework has been used. This approach provides a more accurate description of the electronic and magnetic properties of manganese–ferrites systems. The energy band gap values of 0.38 eV were calculated for MnFe₂O₄, 0.44 eV for Co_0.25Mn_0.75Fe₂O₄, 0.13 eV for Ni_0.25Mn_0.75Fe₂O₄, and 0.24 eV for Cr_0.25Mn_0.75Fe₂O₄, which clearly demonstrate the electronic modulation achieved through selective doping. Similarly, partial magnetic moments, interstitial magnetic contributions, and net magnetization analyses were carried out using spin-polarized (SP)-DFT calculations to explain the overall magnetic behavior. The effect of doping on magnetic properties has been observed and is evident by the net magnetic moment (μ_net) values, calculated to be 6.92 μ_B, 6.05 μ_B, 5.41 μ_B, and 6.67 μ_B for MnFe₂O₄, Co_0.25Mn_0.75Fe₂O₄, Ni_0.25Mn_0.75Fe₂O₄, and Cr_0.25Mn_0.75Fe₂O₄, respectively. This successful modification in electronic structure and magnetic behavior through selective doping of MnFe₂O₄ demonstrates the potential for advanced applications in spintronics and magnetic sensors with enhanced data storage.

This research underscores the capabilities of modified pencil graphite electrodes (PGE) in the electrochemical detection of ascorbic acid. The innovative design of the PGE/chitosan/thiophanate-methyl sensor, combined with the advantages of cyclic voltammetry and square wave voltammetry, offers a promising approach for developing sensitive and selective electrochemical sensors. The surface nano-modification of PGE with chitosan and thiophanate-methyl was confirmed through scanning electron microscopy. The parameters related to electrocatalysis were determined to be: the electron transfer rate constant (log Ks = 2.98), the charge transfer coefficient (α = 0.87), and the surface concentration of electroactive species (Γ = 1.13 × 10^-7 mmol/cm²). A linear correlation was identified for ascorbic acid concentrations between 40 and 380 nanomolars (nM), with a limit of detection established at 13.29 nM. The reproducibility of the modified PGE/chitosan/thiophanate-methyl assay, assessed at a concentration of 140 nM ascorbic acid using five constructed electrodes, resulted in a relative standard deviation (RSD) of 4.85%. The repeatability of the developed sensor for measuring 140 nM of ascorbic acid, determined through 12 measurements with a single constructed electrode, produced a relative standard deviation (RSD%) of 4.68% (146.57 ± 6.87). The electrochemical sensor, in contrast to conventional techniques, allows for rapid analysis, reduced expenses, and supports on-site testing. These sensors are essential tools for the analysis of human blood serum and pharmaceutical samples, as they are not affected by significant side effect interference.

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The renewable, low-cost, and superior physicochemical properties of coconut shell-derived activated carbon (AC) position it as an excellent material for supercapacitor applications. This study focuses on the synthesis, characterization, and electrochemical performance of AC produced from coconut shell using two different activation processes: phosphoric acid and sulphuric acid (PASA), and potassium hydroxide and sulphuric acid (SAPH). Comprehensive analyses of the morphology, pore structure, and electrochemical properties were conducted to elucidate the mechanisms driving the materials’ performance. The optimization of the activation process resulted in the SAPH-AC sample achieving a high specific surface area of 539 m²/g and a pore volume of 0.2772 cm³/g, as determined by Brunauer–Emmett–Teller (BET) and Barrett–Joyner–Halenda (BJH) analyses. The charge contribution analysis showed that SAPH-AC stores charge mainly through capacitive-controlled process, due to the dual activating agent, and exhibits electric double-layer capacitor (EDLC) characteristics. The SAPH-AC sample demonstrated outstanding electrochemical performance, with a specific capacitance of 420.333 F/g at 2 A/g and an impressive energy density of 58.38 Wh/kg in a three-electrode system. These findings underscore the potential of coconut shell-derived activated carbon as a sustainable, environmentally friendly solution for energy storage in supercapacitors, advancing the development of green energy technologies.

The global investigation for sustainable and energy-efficient materials has driven interest in multifunctional intermetallic compounds. Zirconium-based tellurides, such as the ({text{Zr}}_{6} {text{MTe}}_{2}) system, are promising candidates due to their unique layered structures, but their fundamental properties remain underexplored. Therefore, the present investigation employs density functional theory to evaluate the structural, electronic, plasmonic, and thermoelectric transport characteristics of intermetallic ({text{Zr}}_{6} {text{MTe}}_{2} left( {{text{M}} = {text{Co}},{text{Ni}}} right)) compounds. The structural stability of the studied layered intermetallic compounds is confirmed through optimized lattice parameters as well as negative formation energies. Electronic structure calculations reveal metallic behavior, with strong d-orbital contributions at the Fermi level and mixed covalent–metallic bonding characteristics, indicating robust conductivity along with potential anisotropic transport. Plasmonic investigations highlight pronounced ultraviolet resonances with low damping and high-quality factors, suggesting suitability for nanophotonic and ultraviolet plasmonic applications. Thermoelectric transport analysis further supports metallic conduction, characterized by low Seebeck coefficients, high electrical conductivity alongside tunable power factors, pointing toward possible improvement in efficiency via doping or Fermi level engineering. Finally, our investigated ({text{Zr}}_{6} {text{MTe}}_{2}) compounds emerge as stable multifunctional intermetallic systems, offering significant potential for next-generation plasmonic, energy conversion, and thermoelectric device applications.

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The development of dielectric ceramics with superior energy density and efficiency at high dielectric breakdown strength poses a significant challenge for high-power pulse devices and energy storage capacitors. In the present study, we aim to improve the energy storage performance of tungsten bronze structure and perovskite composite ceramics via configurational entropy (ΔS) and interfacial polarization strategies. The (1−x)(Ba_0.34Sr_0.33Ca_0.33)Nb₂O₆-xAgNbO₃ ceramics [(1−x)BCSN–xAN] (x = 0.0, 0.05, and 0.1) were prepared using the solid solution technique in air. The increase in entropy at high concentrations of AgNbO₃-AN caused cation disorder, improved crystal lattice symmetry, and disrupted the long-range ordering of BCSN, which in turn regulated the relaxation behavior. Furthermore, the lower ionic radius of Ag¹⁺ compared to A-site cations induced a reduction in grain size, an increase in the conductivity activation energy, and an increase in grain resistance, which collectively enhanced the breakdown strength at high AN content. The interfacial polarization (Δf) decreased from 18,596 Hz to 2320 Hz in the high-entropy ceramic, indicating improved breakdown strength. This cascade effect results in outstanding energy storage performance, ultimately achieving a recoverable energy density (W_rec) of 6.9 J/cm³ and efficiency (η) of 90.4% in 0.95BCSN-0.05AN ceramics, along with ultrahigh breakdown strength E_b of 710 kV/cm. This research indicates that entropy and interfacial polarization are effective methods for designing tetragonal tungsten bronze dielectric ceramics with ultrahigh comprehensive energy storage performance.

Vector vortex beams, as structured light fields with both orbital angular momentum and inhomogeneous polarization distribution, have shown significant potential in cutting-edge fields such as quantum information, high-dimensional optical communication, and super-resolution imaging. In recent years, metasurfaces, with their remarkable ability to control electromagnetic wavefronts at subwavelength scales, have become core devices for the efficient generation and dynamic manipulation of vector vortex beams. Research in this area holds substantial academic value and promising application prospects. This review systematically summarizes the progress made over the past five years in all-dielectric, metallic, and programmable metasurfaces for the generation and manipulation of vector vortex beams, and provides an in-depth analysis of the advantages of these three types of metasurfaces in this domain. Furthermore, the integration of artificial intelligence with metasurface design and applications is discussed, highlighting its potential to enable intelligent design strategies and adaptive control of structured light. Finally, the future development trends and possible breakthroughs in metasurface-based vector vortex beam manipulation are outlined.