Journal of Materials Science: Materials in Electronics最新文献

This study presents the design and dielectric characterization of an advanced ceramic material derived from mullite-modified bentonite, developed for next-generation electronic components and high-performance electrical insulation systems. A comprehensive structural and microstructural analysis was carried out using X-ray diffraction (XRD), X-ray fluorescence (XRF), field-emission scanning electron microscopy (FE-SEM), and Fourier-transform infrared spectroscopy (FT-IR), enabling a detailed assessment of phase composition, chemical structure, and morphology. Electronic and dielectric properties are central to understanding the functional behavior of insulating ceramics and to predicting their performance across different geometries and operating conditions. Our work adopts a robust methodological framework based on Nyquist and Bode representations, allowing a detailed examination of the complex impedance (Z*), electric modulus (M*), and permittivity (ε*) formalisms. Impedance measurements were conducted over a broad frequency range (0.1 Hz–10 MHz) and at elevated temperatures (400–850 °C), enabling a thorough exploration of the relaxation dynamics and conduction mechanisms governing the material’s dielectric behavior. The dielectric response and AC conductivity were extensively evaluated across the same frequency and temperature ranges. The results demonstrate a pronounced enhancement of both the real (ε′) and imaginary (ε′′) components of permittivity at 850 °C, particularly at low frequencies (0.1 Hz–1 kHz), highlighting the significant contribution of interfacial and space-charge polarization at high temperatures. Moreover, the frequency-dependent conductivity follows Jonscher’s universal power law, indicating that charge transport occurs predominantly through thermally activated hopping mechanisms involving both grains and grain boundaries. This finding underscores the complex, heterogeneous nature of the conduction pathways within the mullite-based ceramic matrix.

In this study, the synthesis, single-crystal X-ray analysis, photophysical properties, DFT, and docking studies of a chalcone analog (2E,4E)-5-(4-methoxyphenyl)-1-(thiophen-2-yl) penta-2,4-dien-1-one (MPT) are reported. The synthesis of the title compound was achieved by the conventional Claisen–Schmidt reaction. The identity of the title compound was confirmed by spectroscopic techniques, and by X-ray diffraction analysis of single crystals. In the solid state, the molecule exhibits weak π–π interactions. The fluorescence spectrum of the title compound in the solid state shows a broad emission with a λ_max at 517 nm and a significant Stokes shift of 142 nm. Using the Z-scan technique the third-order nonlinear optical properties of MPT were explored. The compound displayed a two-photon absorption (β = 2.36 × 10^–6 cmW⁻¹), nonlinear refraction (n₂ = 2.37 × 10^–10 cm²W⁻¹), and a third-order nonlinear susceptibility (χ⁽³⁾ = 3.84 × 10^–8 esu). Theoretical calculations provided insights into structural properties, including the HOMO–LUMO energy gap. Molecular docking studies revealed that the synthesized compound showed the binding affinities of -11.1, -4.9, and -6.6 kcal/mol against the SARS-CoV-2 receptor (PDB ID: DZP). Furthermore, docking studies also suggest that the molecule may inhibit ORF8, a viral immunoglobulin-like (Ig-like) domain protein essential for SARS-CoV-2 binding, fusion, and entry into host cells.

The effectiveness of a supercapacitor is greatly influenced by important factors related to the materials used and the synthesis method applied. In this study, we created flower-like NiCo₂O₄/CuS/rGO nanocomposites using a simple and straightforward chemical bath deposition (CBD) technique. We then conducted a thorough analysis with various characterization methods. We examined the electrochemical properties through galvanostatic charge–discharge (GCD), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). These methods revealed impressive cycling stability and excellent redox performance. Our nanocomposite achieved an outstanding specific capacitance (Cp) of 697.77 F/g at 0.5 A/g, and it retained 512 F/g even at 10 A/g. It also demonstrated remarkable electrochemical stability, holding onto 83.33% of its initial capacity after 1000 cycles. These findings truly highlight the exceptional electrochemical capabilities of NiCo₂O₄/CuS/rGO nanocomposites, making them highly efficient candidates for supercapacitor electrodes. What’s even more exciting is that their performance surpasses that of previously synthesized materials, showcasing their thrilling potential in next-generation energy storage applications.

A collection of oxyapatite-structured Ba₂La₃(SiO₄)₂(PO₄)O doped with varying amounts of Tb³⁺ ions (denoted as BLSPO: xTb³⁺) was prepared via the high-temperature solid-state reaction. The study comprehensively explored the crystalline characteristics, photoluminescence behaviors, and potential applications in LED devices. The XRD results confirmed its phase purity. Photoluminescence and excitation spectra analyses revealed that the optimal excitation wavelength for BLSPO: xTb³⁺ phosphors is 378 nm. Under this excitation, four sharp emission peaks were observed at 491 nm (⁵D₄ → ⁷F₆), 546 nm (⁵D₄ → ⁷F₅), 591 nm (⁵D₄ → ⁷F₄), and 626 nm (⁵D₄ → ⁷F₃). The best luminescent performance was achieved when the Tb³⁺ ion doping concentration was 10 mol%. The concentration quenching mechanism can be effectively explained by dipole–dipole interactions. Additionally, the thermal stability of two samples, BLSPO:10 mol%Tb³⁺ and BLSPO:20 mol%Tb³⁺, was tested. The results indicated an anomalous thermal quenching behavior, where the luminescence intensity increased with temperature rather than decreased. Specifically, the luminescence intensity of the BLSPO:10 mol%Tb³⁺ sample increased to 112% of its initial value at 480 K, while that of the BLSPO:20 mol%Tb³⁺ sample reached 111% at the same temperature, demonstrating exceptional thermal stability. When BLSPO:10 mol% Tb³⁺ samples were used to fabricate green and white LEDs, their CIE chromaticity coordinates were (0.369, 0.512) and (0.323, 0.342), respectively, falling within the green and white regions of the chromaticity diagram. This demonstrates the material’s broad application prospects in LED lighting and display technologies.

The development of novel photocatalytic materials for wastewater treatment through water-splitting mechanisms has garnered significant attention for environmental purification. In this study, we successfully designed and synthesized quantum dots of CdS, Cd₀.₄₉Cr₀.₀₁S, Cd₀.₄₈Cr₀.₀₁Gd₀.₀₁S, Cd₀.₄₇Cr₀.₀₁Gd₀.₀₂S, Cd₀.₄₈Cr₀.₀₁V₀.₀₁S, and Cd₀.₄₇Cr₀.₀₁V₀.₀₂S using a wet chemical method. Structural analysis confirmed that these synthesized quantum dots maintained a cubic zinc-blende crystal structure, like that of pristine CdS. Moreover, optical investigations indicated that all the synthesized samples displayed strong absorption properties in the visible region of the electromagnetic spectrum, making them well suited for photocatalytic uses. Photocatalytic activity tests indicated that Cd₀.₄₇Cr₀.₀₁Gd₀.₀₂S quantum dots demonstrated an impressive degradation efficiency of 92% against methylene blue (MB) organic pollutant in water, outperforming all other synthesized samples. The rate constant for Cd₀.₄₇Cr₀.₀₁Gd₀.₀₂S quantum dots was determined to be 0.0153, which is nearly four times higher than that of pure CdS quantum dots and 1.77 times greater than Cd₀.₄₇Cr₀.₀₁V₀.₀₂S quantum dots. These thorough analyses strongly suggest that Cd₀.₄₇Cr₀.₀₁Gd₀.₀₂S quantum dots are highly promising candidates for the degradation of organic pollutants in water bodies under simulated sunlight exposure.

This research has proven that Radar Absorbing Material (RAM) can be synthesized from natural materials by utilizing iron sand (Fe₃O₄) from volcanoes and coconut shell charcoal as sources of reduced graphene oxide (rGO). The PANI/rGO/Fe₃O₄ with Fe₃O₄ variation 0.5 g (PrGF1); 0.6 g (PrGF2); 0.7 g (PrGF3) were synthesized through a combination of coprecipitation, hummer modification, and in-situ polymerization methods. Characterization was carried out using X-ray diffraction (XRD), scanning electron microscope with energy dispersive spectroscopy (SEM–EDS), electro impedance spectroscopy (EIS), vibrating sample magnetometer (VSM), and vector network analyzer (VNA) to determine the crystal structure, morphology, electrical properties, magnetic properties, and microwave absorption capabilities in the X-band frequency range (8–12 GHz) respectively. The test results showed that increasing the Fe₃O₄ content strengthened the magnetic properties and supported impedance matching through a balance between dielectric and magnetic losses. The best sample, PrGF3, showed a maximum reflection loss value of − 42.41 dB at a frequency of 10.1 GHz, with a reflection coefficient of 0.0075, meaning 99.25% of electromagnetic waves were successfully absorbed. This study confirms that the use of natural materials such as iron sand and coconut shell charcoal can produce RAM that is lightweight, environmentally friendly, and has competitive absorption performance for electromagnetic (EM) wave absorber applications. In addition, this study found that thin samples also have good absorbance values, and all composites have balanced dielectric and magnetic losses.

Controlling synthesis parameters is vital for tailoring the multifunctional properties of magnetoelectric (ME) composites. In this work, we investigate the influence of pH on the structural, morphological, magnetic, and dielectric properties of NiFe₂O₄–BaTiO₃ (NFO–BTO) nanocomposites. Nickel ferrite (NFO) was synthesized via hydrothermal processing at pH values of 6, 8, 10, and 12, while BaTiO₃ (BTO) was prepared using a sonochemical route. X-ray diffraction (XRD) confirmed the formation of biphasic composite structures, with crystallite sizes ranging from 25 to 27 nm and improved phase purity at higher pH. High-resolution scanning electron microscopy (HRSEM) revealed pH-induced morphological variations, transitioning from agglomerated particles to more interconnected and uniform grains. Magnetic characterization using vibrating sample magnetometry (VSM) showed a significant increase in saturation magnetization (Ms) from 17.74 emu/g at pH 8 to 41.31 emu/g at pH 12, attributed to enhanced crystallinity and optimized cation distribution. Dielectric measurements revealed improved permittivity and lower dielectric loss at higher pH, linked to microstructural refinement and enhanced interfacial polarization. These results demonstrate that pH serves as a key tuning parameter for engineering the structural and functional behaviour of NFO–BTO composites, offering insights for the development of high-performance magnetoelectric materials.

This study investigates the development of sustainable, multifunctional vinyl ester composites by incorporating Calamusthwaitesii stem fibers, copper nanoparticles, and biocarbon fillers to enhance mechanical, dielectric, and electromagnetic interference (EMI) shielding properties. Among the formulations, MPB3, containing 40 vol% fiber and 3 vol% biocarbon, demonstrated superior mechanical performance, exhibiting high tensile, flexural, and impact strength, along with notable hardness, due to strong fiber-matrix adhesion and uniform filler dispersion that effectively improved stress transfer and crack resistance. In dielectric characterization, MPC5, reinforced with 40 vol% fiber and 5 vol% copper nanoparticles, achieved the highest permittivity and dielectric loss, attributed to enhanced interfacial polarization and dipolar relaxation arising from the conductive nanoparticle network. For EMI shielding, MPC3, with 40 vol% fiber and 3 vol% copper, delivered the maximum total shielding effectiveness at 18 GHz, driven by efficient absorption and reflection facilitated by well-distributed conductive pathways. SEM analysis corroborated these findings, revealing smooth surfaces in neat composites, fiber breakage in reinforced systems, uniform filler dispersion in high-performing samples, and slight agglomeration in lower-performing ones. Overall, the results demonstrate that integrating natural fibers with functional nanofillers can produce environmentally friendly composites with tunable mechanical, dielectric, and EMI shielding capabilities, highlighting their potential for advanced engineering applications.

The pristine polyvinyl alcohol (PVA) has certain limitations, specifically its electrical insulation properties and the absence of nonlinear optical activity, which limit its potential use in advanced optoelectronic and photonic devices. This study investigates the structural, linear/nonlinear optical, and electrical properties of polyvinyl alcohol (PVA) nanocomposite films doped with ultra-low loadings (0.01—0.1 wt%) of reduced graphene oxide (rGO). XRD and FTIR analyses confirm successful rGO incorporation and strong hydrogen bonding between rGO’s oxygen-containing functional groups and PVA’s hydroxyl groups. SEM reveals homogeneous rGO dispersion at low concentrations, with the onset of agglomeration near 0.1 wt%, consistent with percolation behavior. UV–Vis spectroscopy shows a redshift in absorption and tunable visible transparency with increasing rGO content. TAUC plot analysis indicates significant bandgap narrowing, with the direct gap decreasing from 5.81 to 4.96 eV and the indirect gap decreasing from 4.76 to 3.07 eV, attributed to interfacial hybridization and defect-induced states. Urbach energy rises sharply (0.94 → 5.64 eV), reflecting increased structural disorder. Remarkably, the third-order nonlinear optical susceptibility (χ³) increases by ten orders of magnitude (up to ~ 10^–6 esu), while the dielectric constant surges from 1.25 to 12.39 at 0.1 wt% rGO, driven by Maxwell–Wagner interfacial polarization. AC conductivity confirms the emergence of a percolation network at this threshold. These results demonstrate that trace rGO doping enables simultaneous, tunable enhancement of optical nonlinearity, dielectric response, and electrical conductivity, positioning rGO-PVA as a promising multifunctional platform for flexible optoelectronics, optical limiters, and energy storage devices.