Journal of Materials Science: Materials in Electronics最新文献

Investigating natural substitutes for chemical reagents which detrimentally affect the ecosystem in analytical processes is equivalently crucial as designing readily accessible analytical instruments. Herein, highly photoluminescent carbon dots (CDs) were developed from natural precursor i.e., mustard pods via simple calcination method for fluorescent sensing of metal ions. The diverse instrumental analytical approaches were taken into consideration to characterize the developed CDs which confirmed its complete formation. The synthesized CDs were fluorescent, crystalline and quasi spherical with particle size ~ 8–10 nm. The fluorescent behavior of CDs was utilized in pollutant sensing, especially metal ion sensing for environmental remediation applications. High selectivity and sensitivity were observed towards ferric (Fe³⁺) ions through quenching phenomena by employing CDs in the presence of various other competitive metal ions with a detection limit of 0.042 µM. The efficacy of the developed system was explored in real water samples and exhibited excellent recovery values (> 96%). Further, the current effort not only solves the problem of toxic metal ion sensing but also overlays fortune boulevard towards the utilization of biocompatible precursor sources with extremely beneficial photophysical properties.

A novel semi-organic nonlinear optical crystal, L-asparagine lithium nitrate (LALN), has been synthesized by the slow solvent evaporation solution growth technique at room temperature. The crystalline nature of the grown crystal was characterized by the Powder X-ray diffraction (PXRD) method. The Fourier Transform Infrared Spectroscopy (FTIR) confirms the presence of the functional groups. UV–vis studies reveal a wide transparency window with an optical cutoff at 256 nm, corresponding to an estimated optical bandgap of 4.8 eV, signifying excellent optical quality with a low defect density. Thermo gravimetric analysis confirmed that the compound was stable up to 115 °C, whereas major decomposition occurred above 223 °C. The DTA curve depicts that the melting point of the LALN is around 271 °C. The elemental composition and presence were confirmed by EDAX analysis. Its relative SHG efficiency was found to be 0.65 times that of the standard potassium dihydrogen phosphate (KDP), confirming the non-centrosymmetric nature and significant nonlinear optical activity of the material. The dielectric studies showed frequency- and temperature-dependent polarization with low dielectric loss, hence confirming its suitability for optoelectronic devices.

Iron oxide (Fe₂O₃)/Polyvinylidene fluoride-co-hexafluoropropylene (PVDF-HFP) nanocomposite film is investigated for its potential electromagnetic interference (EMI) shielding applications, particularly in the X-band (8–12 GHz) region. For this purpose, pure PVDF-HFP and Fe₂O₃/PVDF-HFP nanocomposite films are prepared by the solution casting technique. The prepared nanocomposite was investigated through various studies. The characteristic functional group peaks in the Fourier-transform infrared spectroscopy (FTIR) study confirm the successful incorporation of Fe₂O₃ nanoparticles into the polymer matrix of PVDF-HFP. The crystalline structure of Fe₂O₃/PVDF-HFP is revealed by the X-ray diffraction (XRD) data, which shows distinctive peaks of PVDF-HFP and Fe₂O₃ phases. The field emission-scanning electron microscopy (FE-SEM) images depict the homogenous dispersion of the Fe₂O₃ nanoparticles within the polymer matrix and the interaction between the Fe₂O₃ nanoparticles and the PVDF-HFP matrix. Further, at 50 Hz & 150 °C, the incorporation of Fe₂O₃ nanoparticles increased the dielectric constant of PVDF-HFP from 15 to 24, while the dielectric loss decreased from 4.3 to 2.4, resulting in a Q factor improvement from 0.4 to 0.55. Fe₂O₃/PVDF-HFP nanocomposite exhibits frequency and temperature-dependent impedance and AC conductivity, transitioning from insulating to conductive states. Cole–Cole analysis, in addition to dielectric loss tangent, impedance-matching, and attenuation constant evaluations based on complex permittivity, confirms multiple relaxation processes, good impedance matching, and improved internal attenuation in the X-band. The electromagnetic interference shielding effectiveness (EMI SE) studies in the X-band region indicate adequate shielding effectiveness of 8.55 dB. Therefore, Fe₂O₃/PVDF-HFP nanocomposite film provides preferable EMI shielding capabilities, indicating its potential applications in secure communication systems.

This work investigates the effect of green-synthesized NiFe₂O₄ nanoparticles (NPs) on the ion transport and dielectric properties of polyethylene oxide (PEO)–NaNO₃–glycerol nanocomposite polymer electrolytes (NCPEs). NiFe₂O₄ NPs were synthesized via a microwave-assisted green route and incorporated at 0–5 wt.% with and without surface treatment, followed by calcination at 400 and 800 °C. FTIR analysis revealed strong polymer–filler interactions, evidenced by broadened O–H stretching and intensified Fe–O/Ni–O vibrations, which contributed to reduced crystallinity and enhanced ionic mobility. Samples with 0.5 wt.% NPs showed the highest dielectric response, whereas higher loadings suppressed polarization. The modulus formalism and Cole–Cole plots confirmed non-Debye relaxation and faster ion dynamics in optimized samples. For the best-performing composition (IB27: 0.5 wt.% surface-treated NiFe₂O₄ calcined at 800 °C), transport parameters were determined as tan δmax = 4.24, relaxation time τ = 1.049 µs, diffusion coefficient D = 1.13 × 10^⁻3 cm²/s, charge carrier density N = 5.9 × 1013 cm^⁻3, and mobility µ = 4.24 cm² V^⁻1 s^⁻1. To evaluate the combined effects of nanoparticle concentration, calcination temperature, and surface treatment, Response Surface Methodology (RSM) was employed, and contour plots are presented in the Results section. These statistical models confirmed that low filler content (0.5 wt.%), high calcination temperature (800 °C), and surface modification synergistically enhance conductivity. The optimized NCPE achieved a maximum DC ionic conductivity of 111 µS/cm, demonstrating the effectiveness of nanoparticle engineering and statistical optimization in tailoring polymer electrolytes for advanced solid-state sodium-ion batteries and related energy storage devices.

Electromagnetic pollution is a big challenge in today’s wireless technological environment. Microwave absorbers are designed to mitigate this problem. These are the materials that absorb electromagnetic radiation and mitigate its harmful effects on humans and electronic devices. Magnatoplumbite (M-type) hexaferrites with the molecular formula SrCo_yZr_yFe_12-2yO₁₉ were developed utilizing the sol–gel synthesis technique for microwave absorber applications. X-ray diffraction (XRD) was performed to investigate the structural purity of these synthesized hexaferrites. For the investigation on morphology, scanning electron microscopy (SEM) was done. An investigation on the magnetic characteristics was performed using different parameters like saturation magnetization (M_s), coercivity (H_c), remanence (M_r), and anisotropy field (H_a). There is a reduction in coercivity from 5011 to 2688 Oe, with a decrease in ({M}_{s}) from 151.84 to 87.72 emu/g. From the absorption analysis, it was evident that the doping of Zr⁴⁺ and Co²⁺ has improved the absorption. A reflection loss (RL) of -41.70 dB for an 8.3 mm thickness and an input impedance (Z_in) of 383.25 Ω was achieved for composition SrCoZr 5 with a -10 dB absorption bandwidth of 504 MHz. With high absorption and low thickness, the prepared hexaferrites may be a promising candidate for defence and industrial applications as a microwave absorber.

Ag paste has gained considerable attention due to its excellent thermal conductivity and high service temperature. During the sintering process, densification is achieved through neck formation between Ag particles, and a porous structure is inevitably formed. Although sintered Ag paste exhibits high thermal conductivity, its performance remains lower than that of bulk Ag due to the presence of pores. Therefore, introducing doped diamond into Ag paste has been proposed to enhance the effective thermal conductivity of Ag paste. However, accurately predicting and optimizing the effective thermal conductivity of diamond-doped Ag paste remains a major challenge, primarily due to the presence of pores and the complex nature of interfacial thermal resistance. Therefore, based on previous studies on effective medium theory, the influence of pores on the thermal conductivity of composites is considered. The thermal conductivity of three-phase composites composed of pores, doped materials, and matrix is simulated in this paper. Ag-based composites doped with 5 and 15 vol% diamond were fabricated, and the thermal conductivity of diamond-doped Ag paste was measured. The error between the experimental value and the predicted value was 2.4 and 4.1%, respectively. The error significantly lower than the 6 ~ 20% prediction errors commonly reported for sintered Ag paste and composite thermal-conductivity models in previous studies. The model covers the influence of pore shape and porosity, doping particle and matrix type, doping particle size and concentration, coating type and thickness on thermal conductivity, and achieves good consistency at low doping concentration, which can be used to predict the thermal conductivity of three-phase composites at low doping concentration.

Magnetic loss is a key factor limiting the application of nanocrystalline soft magnetic composite materials (n-SMCs) in high-frequency environments, and insulative coating and annealing treatment are important methods to reduce magnetic loss. In this study, a nano-La₂O₃ insulative coating was applied to the surface of FeSiBNbCu nanocrystalline magnetic powder via physical grinding combined with ultrasonic vibration. The effects of nano-La₂O₃ coating content (0–1 wt%) and annealing temperature (455–530 ℃) on the soft magnetic properties of the magnetic powder core were systematically investigated. The results showed that the nano-La₂O₃ coating could significantly improve the insulative performance between magnetic powders and effectively reduce the P_e of n-SMCs. With the increase of nano-La₂O₃ content, the P_e showed a trend of first decreasing and then increasing, reaching the lowest at 0.75 wt%. The P_e decreases from 193.43 mW/cm³ (with 0.0 wt% La₂O₃) to 142.537 mW/cm³ (with 0.75 wt% La₂O₃ at f = 1 MHz), representing a reduction of 26.3%. Meanwhile, by optimizing the annealing process, the residual internal stress in the magnetic powder core induced during compaction is effectively relieved, leading to a significant decrease in hysteresis loss. As the annealing temperature increases, the hysteresis loss of the magnetic powder core reaches its minimum at 505 °C. When the nano-La₂O₃ content was 0.75 wt% and the annealing temperature was 505 ℃, the prepared nanocrystalline magnetic powder core exhibited optimal soft magnetic properties: a stable effective permeability (22.47) and the lowest total loss (230.4 mW/cm³ at f = 1 MHz, B_m = 20 mT), which was 22.89% lower than that of the untreated sample. This study provides a new process scheme for the development of high-performance low-loss n-SMCs.

This work presents the deposition of lead sulfide (PbS) thin films on glass substrates prepared via chemical bath deposition (CBD). The influence of film thickness on surface morphology and structure is investigated. Film thicknesses (300-1200 nm) were prepared layer-by-layer. The films exhibit shiny, continuous, and homogeneous appearances. X-ray diffraction (XRD) reveals that the prepared films were polycrystalline with (200) preferred crystal orientation. Scanning Electron Microscopy (SEM) shows that the agglomeration of grains becomes bigger (increased from 90 ~ 225 nm) with film thickness. Optical transmission and reflectance were employed to study the optical properties of the films in the spectral range 200 to 2500 nm. The optical band gap of the films decreases from 1.55 eV down to 0.93 eV, corresponding to wavelengths 800 nm to 1.3 µm, as the thickness of the PbS film increases from 300 to 1200 nm. The absorption coefficient of the films varies from 10⁴ to 10⁵ cm^-1 in the spectral range of 300 to 2500 nm. The films’ refractive indices in the 800-850 nm range are similar for film thicknesses up to 600 nm, but they show a discontinuity at 850 nm for thicker films. Photoconductive response occurs for film thicknesses of 600 nm or less. In contrast, thicker films do not respond to light.

Thermoelectric materials that efficiently convert waste heat into electricity are gaining attention for their potential in next-generation energy harvesting technologies. In this study, we investigate Fe-doped antimony trisulfide (Sb₂S₃), a structurally anisotropic and abundant compound, as a promising candidate for thermoelectric applications. Fe was introduced via a chemical precipitation route (2, 6, 10, and 12%) and annealed under argon atmosphere. Structural analysis confirmed the orthorhombic Sb₂S₃ phase, with XRD revealing a minor Sb₂O₃ secondary phase at higher Fe concentrations, indicating dopant-induced oxidation and structural reordering. SEM and TEM analyses revealed dense grains and improved interconnectivity at optimal doping levels, while UV–Vis absorption showed band gap modulation from 1.79 eV to 1.60 eV due to Fe incorporation. Seebeck coefficient, electrical conductivity, and Hall measurements revealed a doping-induced conduction-type reversal from intrinsic n-type to p-type (2–10% Fe) and to n-type at 12% Fe accompanied by tunable carrier concentration. Thermal conductivity was suppressed at higher doping levels, attributed to enhanced phonon scattering, aided by grain boundaries and the secondary phases. The combined effects led to improved power factor and overall thermoelectric performance, demonstrating the critical role of Fe doping in tuning transport behavior. This study reports for the first time, that Fe incorporation alters the dominant carrier-type in Sb₂S₃, shifting its conduction mechanism. Such carrier-type modulation provides an effective strategy to optimize the Seebeck coefficient and electrical conductivity simultaneously, thereby offering new opportunities to engineer defect chemistry for improved thermoelectric applications.

A fluorescence enhancement strategy was successfully demonstrated by complexing fluorescein dye with cadmium sulfide (CdS) semiconductor quantum dots (QDs). The influence of varying QD concentrations on the photophysical behavior of 1 × 10⁻⁴ M fluorescein revealed that 5% w/w CdS QDs yielded the optimal balance for energy transfer efficiency and spectral modulation. Additionally, the effect of different dye concentrations within the complex was evaluated to understand concentration-dependent emission dynamics. Comprehensive photophysical characterization of the [Fluorescein: CdS QDs] system in ethanol was conducted, with particular focus on the underlying energy transfer mechanism. FRET-based analyses were employed to extract key parameters, including the critical transfer distance (R₀), thereby elucidating the nature and extent of QD-to-dye energy coupling. Fluorescence enhancement efficiencies were systematically studied under variable input powers using a continuous-wave blue diode laser (λ = 450 nm). The QD-dye hybrid exhibited relatively high emission efficiency, along with a significantly elevated fluorescence quantum yield.