Journal of Electronic Materials最新文献

Bare and Ag@Sm-codoped ZnO nanobullets have been synthesized via a one-step hydrothermal technique with a 1-weight ratio of Sm and a variable 0.5–1.5 weight ratio of Ag. To investigate the actual role played by codoping, a comparative study of bare and Ag@Sm-codoped ZnO nanobullets to nanowires is carried out. The behavior of predicted simulation results and experimental results is the same. X-ray diffraction (XRD) patterns revealed that the nanobullets have grown along the (002) Bragg plane. The (002) peak positions of all codoped samples move towards the lower angle side compared with bare ZnO. The field emission scanning electron microscopy (FE-SEM) results of bare and 1 wt.% of Sm and 0.5 wt.%, 1.0 wt.%, and 1.5 wt.% of Ag codoped ZnO shows open-ended nanobullets with altered morphology from the nanobullets shape to an irregular nanowire shape with larger length and diameter. By increasing the doping content, the average diameter and size of nanowires increase, and the density of nanowires slightly decreases. The as-grown nanobullets to nanowire films were used as photo-electrodes in fabricating dye-sensitized solar cells (DSSCs). The cell made using a bare ZnO photoanode shows an overall power conversion efficiency (PCE) of 0.91%, and the cell made with 1 wt.% of Sm and 1.5 wt.% of Ag codoped ZnO photoanode shows a PCE of 4.43%, which is about 80% higher than that of the DSSC fabricated with bare ZnO. This increase in power conversion is either owing to rare-earth ions doping, which escalates the absorption of light in the wide range of the solar spectrum by up and down conversion, or because of the doping of Ag ions, which reduces the recombination of photo-generated electrons and boosts the high charge carrier mobility. These results show that high-power conversion DSSCs can be fabricated by modifying ZnO photoanodes with Ag and Sm.

The phonon-drag effect in monolayer graphene (MLG) and double-layer MLG–MLG systems has attracted considerable attention due to its potential for high-performance thermoelectric applications. In this double-layer MLG–GaAs–MLG structure, GaAs serves as a spacer layer that not only separates the two graphene sheets but also contributes piezoelectric phonons, thereby strongly influencing the phonon-drag thermoelectric effect. In this work, we investigate the phonon-drag thermoelectric coefficient in a double-layer MLG–GaAs–MLG structure, taking into account both deformation potential (acDP) and piezoelectric (acPE) acoustic phonon scattering mechanisms, as well as interlayer Coulomb screening within the random phase approximation (RPA) on different dielectric substrates (h-BN/Al(_2)O(_3)/HfO(_2)). The results reveal that at low temperatures, (S_g) is dominated by acPE, while at higher temperatures, acDP increases superlinearly with T up to the Bloch–Grüneisen temperature and becomes the primary mechanism, then gradually saturates above (T_{textrm{BG}}). The density dependence exhibits two regimes: at (T ll T_{textrm{BG}}), (S_g) decreases with increasing carrier density due to the Bloch–Grüneisen effect and enhanced screening; in contrast, for (T > T_{textrm{BG}}), (S_g) increases with density owing to the enlarged scattering phase space and the dominance of acDP. With increasing interlayer spacing, (S_g) increases progressively and saturates when (qd gtrsim 1 ; (text {with } q sim k_{F})) approaching the monolayer limit. Under asymmetric density conditions, (S_g) shifts toward the layer with higher conductivity, while dielectric environment effects are evident in the sequence (S_g^{text {HfO}_2}> S_g^{text {Al}_2text {O}_3} > S_g^{htext {-BN}}), though the differences diminish as the MLG interlayer spacing increases. These findings provide a comprehensive understanding of the phonon-drag mechanism in MLG–GaAs–MLG heterostructures and suggest effective thermoelectric tuning through carrier density engineering, interlayer spacing, and dielectric design, which are promising for the development of graphene-based thermoelectric devices.

This study investigates the enhancement of methylcellulose (MC)-based polymer electrolytes by incorporating zinc-doped calcium ferrite (CaZnFe₂O₄) as a nanofiller. The polymer electrolyte system consists of MC as the host polymer, sodium nitrate (NaNO₃) as the salt, and glycerol as a plasticizer. The structural, electrochemical, and dielectric properties of the prepared samples were analyzed to determine the impact of nanofiller addition. Electrochemical impedance spectroscopy demonstrated a dramatic decrease in bulk resistance from 325 Ω (undoped) to 22 Ω (5 wt.% CaZnFe₂O₄), resulting in a 13.8-fold increase in direct current (DC) conductivity (from 7.73 × 10⁻⁵ S/cm to 1.07 × 10⁻³ S/cm). A shift in tan δ peak frequency from ~324 kHz in solid polymer electrolytes (SPE)-No to ~474 kHz in SPE-N5 evidences enhanced charge carrier mobility (shorter relaxation time). Alternating current (AC) conductivity analysis suggests enhanced ion mobility due to strong polymer-filler interactions. The findings suggest that 5% CaZnFe₂O₄ is the optimal concentration for achieving high ionic conductivity and stable electrochemical performance. This optimized polymer electrolyte system holds potential for applications in energy storage devices, including supercapacitors and rechargeable batteries. X-ray diffraction results indicate a reduction in crystallinity with increasing nanofiller content, favoring ion transport. The scanning electron microscope (SEM) results reveal that the CaZnFe₂O₄ particle size is below 50 nm (~37 nm), which favors the easy dispersion of the nanofiller within the polymer matrix. Fourier-transform infrared spectroscopy showed shifts in O-H (3352 cm⁻¹) and C-O-C (1035 cm⁻¹) bands, confirming strong polymer–filler–ion interactions between the polymer matrix, salt, and nanofiller, facilitating improved ionic conductivity.

The continuous increase in nitrogen oxide (NO_x) emissions from combustion processes, primarily from industrial factories and gasoline-powered vehicles, poses a significant threat to all living organisms. The detrimental effects of NO_x on human health and the environment necessitate concentrated efforts to reduce these emissions. Various strategies have been developed to mitigate NO_x emissions from exhaust fumes. Recently, photocatalytic oxidation technologies for removing NO_x have gained considerable attention within the scientific community. Photocatalytic NO_x removal (PNR) is a promising environmentally friendly and cost-effective method for reducing NO_x concentrations at room temperature. This review categorizes and summarizes the multifaceted aspects of PNR. It provides a concise overview of the photocatalytic mechanism and the NO_x abatement process. Investigations reveal that the efficiency of NO_x removal significantly depends on the bandgap and positions of the valence and conduction band edges, which can be tuned by incorporating suitable dopants or forming heterojunctions. The charge transfer at the photocatalyst surface can be enhanced by employing various methods to tune the surface morphology. This review offers comprehensive details on the semiconductor materials used for NO_x abatement and discusses how their unique properties contribute to efficient PNR.

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In this work, we establish models of amorphous Ga₂O₃(a-Ga₂O₃) and its five vacancy defects using molecular dynamics and density functional theory. Through hybrid functional calculations, we calculate the electronic structure, defect formation energies, and optical properties of these models. We explain the structural characteristics of the a-Ga₂O₃ model through bond lengths, bond angles, and radial distribution functions. Based on the coordination of oxygen and gallium atoms in the a-Ga₂O₃ model, the defects are divided into three types of oxygen vacancies (V_O) and two types of gallium vacancies (V_Ga). Electronic structure calculations show that V_O will introduce defect states in the band gap, which are contributed by the O 2p states and Ga 4s or 4p states. The V_Ga will induce spin polarization through the dangling bonds of the 2p orbitals of the surrounding oxygen atoms. The defect formation energy of V_O is lower than that of V_Ga, and a-Ga₂O₃ is more likely to exhibit n-type conductivity. The discussion on the changes in the optical absorption spectra and the imaginary part of the dielectric function reveal that different types of V_O and V_Ga cause optical absorption near 3 eV, 2.88 eV, 3.28 eV, 1.6 eV, and 3.45 eV, respectively. The introduction of defects increases the number of absorption peaks and induces a red shift in the absorption edge. This work provides a reference for explaining the influence mechanism of neutral vacancy defects inside a-Ga₂O₃ materials on the electronic structure and optical properties of the material.

To address the issues of poor load-bearing capacity, low design efficiency, and the difficulty of integrating structural and functional design in current absorbing structures, a study on the integrated reverse design of load-bearing metamaterial absorbers was conducted. A parametric model of the load-bearing metamaterial absorber was developed using a combination of composite core structures and electromagnetic resonant layers. A dataset of electromagnetic and structural properties of the absorber was established. A deep learning-based forward prediction network for the absorber’s absorbance and a design parameter reverse prediction network were developed and trained, achieving high-accuracy predictions of both the absorbance and design parameters. Based on the forward and reverse prediction networks, an integrated reverse design method for metamaterial absorbers was proposed. This method enables the reverse design of the metamaterial absorber on the basis of specified electromagnetic and structural properties while addressing the issue of unattainable design goals through polar coordinate transformation. The method was applied to reverse design tasks for single-frequency, multi-frequency, and broadband load-bearing metamaterial absorbers. The proposed integrated reverse design method holds significant potential for applications in radar stealth material design for military targets, such as naval vessels, and offers broad generalizability and engineering applicability.

We present NanoSensorLab, an open-access MATLAB-based simulation toolbox grounded in Mie scattering theory for the advanced modeling and optimization of plasmonic nanoparticle-based sensors. The toolbox comprises two integrated modules: Nanoscattering, which computes scattering (Q_sca), absorption (Q_abs), and extinction (Q_ext) efficiencies alongside key optical metrics such as peak wavelength, line width, and quality factor (QF); and Nanosensor, which evaluates sensor performance parameters including sensitivity (S) and figure-of-merit (FOM). NanoSensorLab supports multilayered spherical geometries, nanoshells, nanomatryoshkas, and gain-assisted configurations, and incorporates a material library that includes noble metals, transition metal nitrides, and graphene with user-defined optical properties. The toolbox enables rapid design of high-performance LSPR-based sensors and facilitates parametric studies via an intuitive graphical interface. Simulations demonstrate that graphene-integrated TiN-based nanomatryoshkas can achieve sensitivities up to 925.28 nm/RIU, representing a 125.52% enhancement over conventional designs. Benchmarking against COMSOL Multiphysics validates the numerical accuracy of the implementation. NanoSensorLab offers a streamlined, customizable platform for designing plasmonic biosensors targeting biomedical diagnostics such as glucose monitoring and cancer cell detection. The toolbox is freely available at: https://github.com/aloksinghphy/Toolbox.

Understanding the mechanisms of charge storage in supercapacitors is crucial for optimizing their performance in advanced energy storage applications. Supercapacitors exhibit a blend of both electric double-layer capacitance (EDLC) and pseudocapacitance, making it essential to differentiate these contributions for material design and device optimization. Among various analytical methods, Dunn’s method, which uses cyclic voltammetry (CV) at varying scan rates, has emerged as a widely employed technique. As it is a relatively straightforward approach for deconvoluting capacitive and diffusion-controlled processes, this review provides a comprehensive overview of Dunn’s method, encompassing its theoretical background, analytical procedure, advantages, limitations, and applications across diverse electrode materials. Furthermore, the comparison of Dunn’s method with other electrochemical characterization techniques such as electrochemical impedance spectroscopy (EIS), galvanostatic charge–discharge (GCD), and Trasatti’s method also underscores future prospects for enhancing its accuracy and applicability. This review aims to serve as a practical guide for researchers looking to employ Dunn’s method in supercapacitor research.

This study systematically investigates the effects of surface finishes on the interfacial microstructure and shear-speed-dependent mechanical properties of Sn-Ag-Cu (SAC)-based solder joints. Two lead-free alloys, SAC305 and Innolot, were paired with four surface finishes, organic solderability preservative (OSP), immersion tin (ImSn), immersion silver (ImAg), and electroless nickel/immersion gold (ENIG), to assess their influence on intermetallic compound (IMC) formation, shear strength, and fracture behavior. Distinct IMC growth kinetics and morphologies were observed: OSP promoted rapid IMC growth with scalloped structures, while ENIG produced thinner, planar IMCs due to diffusion suppression. Innolot’s multi-element composition further refined IMC grains compared to SAC305. Shear testing across five speeds (0.01–1000 mm/s) revealed strong dependencies on both surface finish and strain rate. SAC305 joints followed a shear strength trend of ENIG > OSP > ImAg > ImSn, whereas Innolot exhibited more complex behavior, with OSP performing best at low speeds and ENIG at high speeds. Both alloys showed strain-rate strengthening, with SAC305 being more sensitive. Fracture modes shifted from ductile (bulk solder) to brittle (IMC interface) with increasing shear speed, with Innolot transitioning earlier. ENIG consistently outperformed other finishes by combining thin IMCs and robust adhesion, making it highly suitable for harsh environments. These findings offer valuable guidance for optimizing surface finishes in high-reliability electronic packaging.

Coal-based active carbon (CAC) is an ideal supercapacitor (SC) electrode material owing to its rich microporosity, high surface area, and excellent capacitance. Taixi anthracite (TXA) features high fixed-carbon content (<8% ash) and a well-ordered microporous structure. This renders TXA critical for CAC-based SC electrodes. For non-biomass SC electrodes, ash content management is critical. In this study, CAC was obtained by physical and chemical sequential activation of TXA using H₂O and KOH. Ultralow-ash D-CAC was prepared via oxalic acid deashing of CAC, with process conditions optimized. CAC’s extensive porosity enables efficient oxalic acid penetration and deashing. D-CAC demonstrated superior specific capacitance and cycling stability. D-CAC had the largest specific surface area of 2106 m²/g and a total pore volume of 1.03 cm³/g. D-CAC also exhibited a high specific capacitance of 339.4 F/g at a current density of 0.5 A/g. After 10,000 charge and discharge cycles, the specific capacitance showed a 99.1% retention rate. Furthermore, assembled symmetric SC exhibited a high specific capacitance of 156 F/g at 0.5 A/g and an energy density value of 6.25 Wh/kg with a power density of 12,500 W/kg. This organic acid (OA) deashing strategy enables the production of high-performance capacitive carbon.