Journal of Materials Science: Materials in Electronics最新文献

In this paper, alkali-free boroaluminosilicate glasses with low thermal expansion coefficient and low dielectric loss were prepared. The effect of Bi₂O₃ substitution for CaO on structure, thermal expansion, elastic modulus, and dielectric properties of the samples was investigated by Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), thermal dilatometer, ultrasonic thickness gauge, and impedance analyzer. The results show that the polymerization degree of the glass network structure increases first and then decreases, which reaches the highest with the substitution of 0.5 mol% Bi₂O₃ for CaO. The thermal expansion coefficient and dielectric constant decrease and then increase, while elastic modulus shows the opposite trend, which is attributed to the change in the glass network structure. The atomic mass of Bi much greater than that of Ca causes the obvious increase of glass density. The ionic radius of Bi³⁺ ions is larger than that of Ca²⁺ ions, making it more difficult to migrate through the glass network, reducing dielectric loss. In particular, the sample with 0.5 mol% Bi₂O₃ substitution shows excellent properties, such as low thermal expansion coefficient (3.07 × 10^–6/K), high elastic modulus (80.58 GPa), low dielectric constant (5.52), and dielectric loss (3.15 × 10^–3), which is very suitable for use as chip packaging material.

In this study, a hot-pressing sintering (HPS) was firstly performed for LiZnTi ferrites sintered from 850 to 1050 °C. To analyze feasibility of co-firing, the as-sintered HPS^1st samples were then subjected to a traditional sintering (TS) process at 950 °C. The influences of sintering temperature and second sintering on the crystal phase formation, microstructure, and gyromagnetic properties of the LiZnTi ferrite were systematically investigated. X-ray diffraction confirmed that all the samples exhibited a pure spinel structure. SEM images indicated that the grain size and bulk density of the samples have increased with the increase in temperature. Due to the second sintering with a long time, all the samples exhibited a secondary growth. The magnetic hysteresis (M-H) loops confirmed that sintering temperature could enhance saturation magnetization intensity and the samples kept a stable value after second sintering. The results of ferromagnetic resonance (FMR) linewidths revealed that the 1000HPS^1st sample had a small value (ΔH = 298.25 Oe) and could also keep a good and stable value after second sintering. Thus, the LiZnTi ferrite sample prepared by hot-pressing sintering was feasible for co-firing with other ceramic (dielectric ceramic) for microwave applications.

The development of X band (8.2–12.4 GHz) electromagnetic wave (EMW) absorbing materials with small thickness and effective absorption bandwidth is crucial for the advancement of portable electronic devices and stealth materials. This study uses an ultrasonic approach and electrostatic self-assembly to create a three-dimensional network structured film, integrating points (liquid metal, LM; nickel particles, Ni), lines (bacterial cellulose, BC), and surfaces (graphene oxide, GO) through vacuum filtration and freeze-drying. In the Ni/LM/GO/BC composite films, BC and GO serve as “donors” for LM anchoring and packaging, while also providing the basic “skeleton” or “grid” for constructing the three-dimensional structures. This resulted in the formation of numerous heterogeneous interfaces and conductive networks among BC, GO, and the metal particles. The GO/BC (GB) film exhibits poor electromagnetic wave absorption performance and does not meet the required standards. However, when LM was added alone, the performance improved, and the EAB extended across the X band. The introduction of magnetic Ni nanoparticles further enhanced the EWA capacity, owing to the combined dielectric and magnetic loss mechanism. The composite film achieved a minimum reflection loss of − 43.56 dB at 2.8 mm and an EAB of 4.2 GHz, effectively covering the X band. The enhanced EWA performance can be attributed to the synergistic effects of dielectric loss, magnetic loss, interfacial polarization, and the multilayer structure. This study demonstrates that a promising wideband EMW absorbing film was developed by exploiting the synergistic electromagnetic effects.

With low redox potential, natural abundance and cost-effective of sodium resources, sodium-ion batteries (SIBs) are considered as a promising alternative for the currently dominant energy storage devices, i.e., lithium-ion batteries. However, developing suitable anode materials is still a challenge for the practical applications of SIBs. Alloy anodes have high specific capacity and low operating voltage, but the inherent volume expansion results in rapid capacity decay and poor cycling stability. Herein, focus on this issue, a novel carbon-coated alloy composite (SbSn@C) was synthesized by the solid-phase reduction of chloride method. Surface morphology analysis confirms that the SbSn@C composite exhibits a porous structure with a carbon layer of 20–30 nm, which can accommodate volume expansion. Furthermore, the synthesized SbSn@C composite exhibits impressive electrochemical performance with a good reversible capacity (450.5 mAh g⁻¹ after 100 cycles, 90% capacity retention). As expected, such synthesis strategy provides a basis for the development of cost-effective and environmentally friendly sodium-ion batteries.

In this study, flexible elastomers are developed as microwave absorbers for industrial and defence applications by incorporating strontium ferrite (SrFe₁₂O₁₉) and titanium carbide (TiC) into a thermoset polyurethane (PU) matrix. These samples are characterized for their morphological, structural, and thermal properties employing FE-SEM, FTIR, XRD, and TGA analysis, respectively. The hardness, tensile test, and tear resistance of elastomers are used to determine the mechanical properties. These elastomers are characterized for their microwave absorption properties in X-band frequency region. It exhibits a minimum reflection loss (RL) of − 28.14 dB in the X-band with a bandwidth of 3.5 GHz. The synergistic interaction between magnetic-dielectric phases improves the impedance matching within the thermoset polyurethane elastomer. SrFe₁₂O₁₉-TiC/PU elastomer exhibits excellent thermal, mechanical, and electromagnetic absorption properties, making them ideal for use in microwave absorption applications, including industrial such as anechoic chambers and defence purposes.

This study reports the synthesis of tin (IV) oxide (SnO₂) nanoparticles (NPs) using the micro-emulsion method and its performance on n-type Si semiconductors under various operating conditions. The physical characteristics of SnO₂ were examined using XRD, SEM, TEM, and UV–Vis analysis. XRD analysis revealed that SnO₂ has a crystalline structure with an average crystallite size of 14.4 nm. The optical band gap energy of SnO₂ was determined as 3.4 eV using UV–Vis analysis. Additionally, the current–voltage (I–V) characteristics of the Au/SnO₂/n-Si/Al and Au/n-Si/Al devices were measured in darkness to explore the influence of SnO₂ nanomaterial on their electrical parameters. From the I–V measurements, the rectification ratio, saturation current, ideality factor, and barrier height values for the SnO₂/n-Si device were determined to be 4.35 × 10⁴ (at ± 2 V), 1.96 × 10^–9 A, 1.57, and 0.81 eV, respectively. For electro-optical characteristics of the SnO₂/n-Si device, the I–V measurements were conducted under both visible light and UV light (365 nm) conditions. The SnO₂/n-Si device, featuring a self-powered property, exhibited superior ON/OFF ratio, responsivity, and detectivity under UV light compared to white light illumination. Therefore, we can assert that the SnO₂/n-Si device holds significant promise for sensitive light detection applications, particularly in UV-sensitive optoelectronic devices.

Designing and developing friction layer materials that are environmentally friendly and recyclable is key to preparing triboelectric nanogenerators (TENG). Herein, a recyclable friction layer material, CFPU-X, has been introduced. This material is dynamically crosslinked through a Diels-Alder reaction between a polyurethane (MPU) containing maleimide groups and carboxylated cellulose nanocrystals with furan groups. The reaction enhanced the cross-linking degree of polyurethane, resulting in a significant increase in tensile strength, with CFPU-15 exhibiting a maximum value of 18.18 MPa, a 761.61% improvement over MPU. Notably, CFPU-9 demonstrated self-toughening properties, possibly attributed to the growth of molecular chains in the same space after heating and redissolution. This resulted in an increase in hydrogen bonding content and a more compact reconfigured crosslinked network, leading to a 145.83% increase in elongation at break. The CFPU-12 TENG is expected to be utilized in medical diagnostics, motion analysis, and health monitoring. This study offers worthy ideas for the development of recyclable materials for high-performance, flexible energy harvesters.

Diluted magnetic semiconductors (DMSs) are vital for advancing spintronic technology, though the origin of their ferromagnetic properties remains contentious. The fundamental question persists whether these magnetic properties arise from intrinsic material characteristics or dopant incorporation. This study investigates the effects of rare earth Nd³⁺ ion doping in SnS₂ to address this uncertainty and explore potential optoelectronic applications. We synthesized two-dimensional Nd-doped SnS₂ nanoparticles (Sn_1−xNd_xS₂) with varying Nd concentrations (x = 0.00, 0.01, 0.03, 0.05, 0.07) and examined their structural, morphological, optical, and magnetic characteristics. X-ray diffraction and Raman studies confirmed the hexagonal phase of SnS₂ nanoparticles. FESEM revealed flower-like or layered structures, while EDAX and XPS confirmed the presence of Sn⁴⁺, S²⁻, and Nd³⁺ ions without impurities. Optical properties, including refractive index and bandgap, were tunable through Nd doping. Raman analysis showed a red shift in the A_1g mode, indicating successful Nd incorporation. Photoluminescence spectra exhibited defect-related emissions, including a sharp near-infrared peak relevant to fiber optic communications. Notably, weak room temperature ferromagnetism was observed in Nd-doped SnS₂ nanoparticles in the low field, potentially linked to Sn vacancies. Magnetic field and magnetization (M–H) measurements of Nd-doped SnS₂ demonstrate the coexistence of ferromagnetic and paramagnetic behavior at low temperatures.

Among the notable features of the lead-free material KNbO₃ (KNb) are its exceptional energy storage density (W_rec) and high breakdown electric field strength (E_b). However, the considerable energy loss associated with KNb limits its applicability in energy storage, adversely affecting both W_rec and efficiency (η) under strong electric fields. This study explores an innovative approach to enhance the energy storage capacity of NBT-SrT-xKNb ceramics (x = 0.1–0.4). The incorporation of KNb disrupts the long-range ordered structure and effectively reduces grain size, resulting in the formation of polar nanoregions (PNRs) that help mitigate energy density loss. As the concentration of KNb increases, significant improvements in both W_rec and η are observed. NBT-SrT-xKNb (x = 0.3) exhibits the best performance among all variations, achieving a high energy storage density (W_rec = 3.13 J/cm³), rapid conversion efficiency (η = 85%), and excellent breakdown strength. Under a mild electric field 30 kV/cm, the substitution of KNb results in a significant strain response of approximately 0.24%. Additionally, a longitudinal strain value of 129 pC/N was recorded. These lead-free ceramics present compelling candidates for current energy storage applications as well as next-generation electro ceramics.