Journal of Electronic Materials最新文献

Copper-to-copper (Cu–Cu) bonding is a key technology for enabling multi-chip stacking in three-dimensional integrated circuits (3D ICs). Among various bonding methods, thermal compression bonding is the most commonly used technique for forming reliable Cu–Cu joints. However, reducing the bonding temperature while maintaining high bonding quality remains a major challenge, particularly for thermally sensitive devices. Due to the size-dependent properties of metal nanostructures, their sintering temperatures are significantly lower than those of bulk materials, making them attractive as bonding interlayers. Copper nanowire arrays (Cu NWAs) are especially promising due to their excellent electrical, thermal, and mechanical performance. Nevertheless, their tendency to oxidize in air increases the overall process complexity. In this study, Cu NWAs with an average diameter of 177.7 nm were fabricated on copper substrates using template-assisted electrodeposition. The effects of three organic solvents, namely glycerol, ethylene glycol (EG), and polyethylene glycol (PEG), on the heating behavior of Cu NWAs in ambient air were systematically investigated. Glycerol demonstrated superior antioxidant and reducing properties. Through glycerol-assisted sintering at 210°C for 15 min in air under a pressure of 7.59 MPa, Cu–Cu joints with an average shear strength of 20.41 MPa were obtained. However, as the bonding pressure increased from 20 MPa to 40 MPa, the shear strength decreased. Coarsening of nanowires was observed when the sintering temperature was increased to 230°C. In contrast, without glycerol protection, nanowires were found to transform into nanotubes. This work provides a feasible route for low-temperature Cu–Cu bonding in ambient conditions, which could support the advancement of interconnects in 3D ICs.

With the urgent demand for high-performance energy storage materials in the global energy transition, traditional experimental trial and error methods are difficult to meet the rapid research and development needs owing to long cycles and high costs. In recent years, the deep integration of computational materials science and artificial intelligence (AI) technology has provided revolutionary tools for the rational design and performance optimization of energy storage materials. This article systematically reviews the progress of research on energy storage material computation and AI systems. At the traditional method level, quantum mechanics computation (such as VASP, Quantum ESPRESSO), molecular dynamics (such as LAMMPS, GROMACS), and high-throughput computing platforms (such as Materials Project) have achieved accurate predictions of material electronic structure, interface dynamics, and high-throughput screening. At the AI-driven level, generative models (GNoME, 3D-GPT), graph neural networks (MEGNet, CGCNN), and experimental computational closed–loop systems (such as the autonomous driving laboratory A-Lab) have significantly accelerated the discovery and reverse design of new materials. Further focusing on the integration trend of multi-scale modeling and AI, physical information-driven AI models (DPMD, PINNs) and cross-scale integration platforms (ASE, MedeA) are driving the collaborative improvement of material simulation accuracy and efficiency. However, data scarcity, computational bottlenecks caused by multi-physics coupling, and barriers to tool industrialization remain current challenges. In the future, sustainable design paradigms, open-source ecological construction, and human-machine collaboration models will lead the research and development of energy storage materials into the era of “digital priority.” This article aims to provide a technical roadmap reference for interdisciplinary research and call for collaboration between academia and industry to overcome key bottlenecks and accelerate the innovation breakthrough and large-scale application of energy storage materials.

Traditionally sintered (TS) BiFeO₃-0.33PbTiO₃-0.13Ba(Zr_0.5Ti_0.5)O₃ (BF-PT-BZT) ceramics have attracted much attention due to their high Curie temperature (T_C) and excellent piezoelectric properties. However, the rapid reduction of resistivity and coarse grain size greatly limit their resistivity and mechanical strength at elevated temperatures. In this work, BF-PT-BZT ceramics were prepared using the two-step sintering (TSS) solid-state reaction method. Specimens were first sintered at a higher temperature (T₁) without holding and then sintered at a lower temperature (T₂) for 8 h. The results show that not holding at T₁ effectively inhibited grain growth, while a long sintering time at T₂ promoted ceramic densification. BF-PT-BZT ceramics sintered at T₁and T₂of 1085°C and 950°C, respectively, exhibited enhanced T_C and piezoelectric constant (({d}_{33})) of 465°C and 370 pC/N, respectively. The resistivity at 400°C of the TSS ceramics was as high as 5.05 (times ) 10⁵ Ω·cm, which is higher than that of the TS ceramics. X-ray photoelectron spectroscopy (XPS) analysis revealed that two-step sintering reduces the concentration of defects and oxygen vacancies, resulting in enhanced insulation properties of BF-PT-BZT ceramics. Our results indicate that TSS-treated BF-PT-BZT ceramics exhibit reduced grain size and enhanced piezoelectric properties, making them suitable for high-temperature piezoelectric sensor and actuator applications.

In the fields of wearable sensors, energy harvesting and actuator applications, organic–inorganic composite piezoelectric materials have gained significant research interest owing to their tunable performance, flexibility, light weight, and facile fabrication. In this work, composite piezoelectric films were fabricated by dispersing hydroxylated BaTiO₃ (BTO-OH) nanoparticles into polyvinylidene fluoride-hexafluoropropylene copolymer (P(VDF-HFP)). The β phase content was found to increase with filler concentration, reaching a maximum of 89.67% in films containing 50% BTO-OH, which acted as a nucleating agent for β phase crystallization. Moreover, the 50% BTO-OH composite film exhibited exceptional dielectric properties, featuring a dielectric constant of 19.8 and a loss tangent of 0.08 at a frequency of 10³ Hz. The maximum polarization reached 8.8 μC cm⁻² under an electric field of 3000 kV cm⁻¹. The piezoelectric strain coefficient d₃₃ reached 20.5 pC N⁻¹. This work offers an efficient and low-cost approach to the fabrication of BTO-based dielectric and piezoelectric composites.

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The development of spintronic, nonlinear photonic, and optoelectronic technologies depends on multifunctional single crystals. In this work, slow ethanol evaporation was used to generate red-colored (E)-(3-(3-methylthiophen-2-yl)acryloyl)ferrocene (TF) single crystals over a period of 59 days. The crystals formed in the monoclinic system (space group Cc) with a unit cell volume of 1479.12 ų. Excellent optical transparency was demonstrated by the crystals, which have a strong absorption edge at 258 nm and maintain ~ 69% transmittance across the visible and near-infrared spectrum. Notably, TF crystals use femtosecond pulse optical rectification to produce broadband terahertz radiation. They exhibited a high piezoelectric coefficient of 22.86 pC/N, strong ferromagnetism, and noticeable ferroelectric polarization switching with remnant polarization. Mechanical hardness of about 130 kg/mm² was achieved. According to nonlinear optical characterization, there was a noticeable third-order susceptibility (7.14 × 10⁻⁸ esu) and a second harmonic generation efficiency that was 3.2 times that of potassium dihydrogen phosphate (KDP). TF crystals are interesting prospects for multifunctional device applications due to their unusual combination of optical transparency, terahertz emission, ferromagnetism, ferroelectricity, piezoelectricity, and strong nonlinear optical response.

Sintered silver is widely used for reliable interconnects in silicon carbide (SiC) power module packaging but is limited by high cost and significant ionic migration issues. Sintered copper offers a promising, cost-effective alternative. Despite its potential, comparative studies on the mechanisms behind the high reliability of sintered copper remain limited. This work develops finite element models of SiC power modules with sintered silver and sintered copper die attaches for comparative thermomechanical analysis and fatigue lifetime prediction, where the viscoplastic behavior is represented using the Anand model and fatigue lifetime is predicted based on the Engelmaier model. The results show significant stress concentration at the die attach interfacial corners near the substrates, with higher stresses in the sintered copper layer and larger equivalent viscoplastic strain in the sintered silver layer. The viscoplastic dissipation energy density in both die attach layers concentrates at the interfacial corners near the directionally bonded copper substrate, where fatigue cracks are more likely to initiate. Cracks initiate earlier in the sintered silver layer than in the sintered copper layer. Although the sintered copper layer experiences higher thermal stress, the higher yield strength of sintered copper and the lower coefficient of thermal expansion (CTE) mismatches between the sintered copper and the copper substrate result in less viscoplastic strain accumulation in the sintered copper layer, leading to less fatigue damage in the sintered copper layer than in the sintered silver. The fatigue lifetime of SiC power modules with sintered copper die attach is significantly longer than that with sintered silver, and the simulation results align with experimental observations.

Rotational speed is one of the critical parameters for evaluating the operating status of rotating machinery. For its detection, a kind of soft-magnetic particle was selected, called carbonyl iron particles (CIPs), having excellent magnetic response characteristics. A sensitive unit based on the magnetoresistance effect was designed in combination with CIPs for sensing the rotational speed, being called the magnetoresistance sensitive unit (MRSU). The magneto-induced performance of the MRSU was investigated by using a self-built experimental system, and the magnetoresistance characteristics of the MRSU were studied through static and dynamic magnetic field-dependent experiments. The mechanism of the magnetoresistance effect was explored and analyzed from the microscopic level, and the relationship between the resistance and the excitation magnetic field was qualitatively deduced. Different test rotational speeds were set in this study, and the output voltage signals of the voltage dividing circuit were used to characterize the rotational speed. The research results show that the range of magnetic field effects on CIPs can be divided into a magnetic working region and a magnetic saturation region, and the excitation magnetic field had a significant impact on the magnetoresistance effect of the MRSU, for both the absolute and the relative magnetoresistance effect within the magnetic working range. In addition, the MRSU exhibited periodic pulse output signals that were consistent with the rotational speed at different test values, indicating that it not only offered very good accuracy but also possessed good temporal stability. The MRSU showed exhibited good magneto-sensitive performance and a stable response, enabling a novel approach for rotational speed detection.

High configurational entropy (ΔS) in dielectric ceramics is promising for high-power pulse applications. However, their low recoverable energy storage density (W_rec) and low breakdown strength (E_b) remain major challenges for achieving superior energy storage performance. Herein, three different systems were investigated on the basis of low-entropy (Na_0.5Bi_0.5)TiO₃ (NBT, ΔS = 0.69R), medium-entropy (Na_0.3Bi_0.3Sr_0.3Ba_0.1)TiO₃ (NBBST, ΔS = 1.31R), and high-entropy (Bi_0.2Na_0.2Nd_0.2K_0.2Ba_0.2)TiO₃ (NNBBKT, ΔS = 1.61R) ceramics, derived from the NBT system, to disrupt their long-range ferroelectric order via A-site cation disorder. The results revealed that the high-entropy ceramic significantly induced a weakly coupled relaxor phase along with suppression of remnant polarization, leading to a remarkable increase in breakdown strength. The elevation of grain resistance (R_g) at high entropy caused a mismatch between grain and grain boundary resistance (R_gb), resulting in the pinching of interfacial polarization. These cascade effects achieved a high W_rec of 6.2 J/cm³ with a large conversion efficiency (ƞ) of 92.8% at an ultra-high E_b of ~500 kV/cm in the high-entropy NNBBKT ceramic. The present work demonstrates that high entropy and the suppression of interfacial polarization are promising strategies for enhancing the energy storage performance of dielectric ceramics.

As a key material for power conversion equipment, soft magnetic composites require high magnetic permeability and low eddy current losses to adapt to the development of high-frequency and miniaturization of electronic devices. In this work, in order to effectively combine the advantages of organic and inorganic coating agents, FeSiBCr amorphous soft magnetic composites insulated with silicone/Fe₃O₄ composite coating were fabricated, and the effect of the content of silicone/Fe₃O₄ on the magnetic properties of the composites was investigated. A simplified finite element model was developed using Maxwell software to investigate the mechanism of insulating coating effects on eddy current losses in the composites. The results show that the density of the soft magnetic composite coated with 5% silicone resin/Fe₃O₄ increased by 14.9%. Appropriate addition of silicone/Fe₃O₄ coating agent thus improved the frequency performance of the FeSiBCr soft magnetic composite, demonstrating good high-frequency stability. When the content of silicone/Fe₃O₄ was 3%, the real part of the permeability of the material was the largest, the eddy current loss factor and hysteresis loss factor were the lowest, and the magnetic loss value was the lowest. Core loss of the 3 wt.% silicone/Fe₃O₄-coated sample was 41.53 W/kg (at 0.05 T and 140 kHz), which was decreased by 19.23% compared to that with 1 wt.% silicone/Fe₃O₄ coating.

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Natural dyes have made dye-sensitized solar cells (DSSCs) a promising technology owing to their biodegradability, affordability, fabrication simplicity, and cost-effectiveness. This study used the response surface method to determine the best anthocyanin extraction conditions from black plum (Syzygium cumini) fruits. Anthocyanins from several plants have been isolated for photovoltaics. However, anthocyanins from Syzygium cumini differ from other sources owing to their wider spectrum coverage, greater light-harvesting efficiency, chemical resistance, and sustainability. The experimental parameters considered for optimization included pH, extraction time, temperature, and solvent type. The analysis of variance (ANOVA) showed that pH and solvent type significantly affect the extraction of anthocyanin dye among the selected variables, with a p value < 0.05. The model was able to accurately predict the maximal extraction yield of anthocyanin from black plum with a relative error of 0.59 %, as indicated by the experimental data. The extracted dyes were characterized regarding their size distribution, surface charge characteristics, and energy states. The results showed that the extracted dyes possessed an average diameter of 0.3 nm and a zeta potential of ± 5 mV, signifying adequate colloidal stability for adsorption onto the TiO₂ surface. However, the experiments showed that the anatase TiO₂ paste with a mean size of 21.88 nm, a porosity of 0.49, and a pore size of 13.24 nm was a good candidate for dye adsorption. The impact of electrolyte conductivity on the cells efficiency was assessed by injecting iodide/triiodide at various concentrations into the cells. The photovoltaic experiments demonstrated that increasing the electrolyte conductivity from 15.96 mS/cm to 26.3 mS/cm increased the efficiency and short-circuit current of the DSSC by 78% and 44.5%, respectively. However, as the electrolyte conductivity increased further, efficiency and short-circuit current decreased, owing to increased recombination and obstruction of light absorption by the electrolyte. The results indicated that coating the internal and external surfaces of the semiconductor with a concentrated dye solution enhanced light-harvesting efficiency; however, it is essential to optimize the electrolyte solution’s concentration to prevent recombination reactions throughout the cell and attain greater efficiency.