Journal of Materials Science: Materials in Electronics最新文献

The development of environment-friendly, lead-free piezoelectric ceramics is a significant challenge in advanced functional materials. In this work, (1–ϕ) [Li₀.₀₆(K₀.₅Na₀.₅)₀.₉₄NbO₃]–ϕSrBi₂Nb₂O₉ [(1–ϕ)KLNN–ϕSBN] ceramics (ϕ = 0 and 0.5 mol%) were synthesized via solid-state reaction. Structural analysis confirmed an orthorhombic-to-tetragonal phase transition due to SBN incorporation in KLNN. Microstructure evolved from uniform to cubical-platelet grains (~ 0.3–0.4 μm) with increased porosity. The dielectric measurements confirm enhanced phase stability, with the orthorhombic-tetragonal transition temperature shifting from 230 to 330 °C, alongside retention of elevated Curie temperatures (Tc > 550 °C). The KLNN-SBN (0.5 mol %) composition exhibited optimal dielectric performance (ε_r ≈ 352, tan δ ~ 0.09 at 50 kHz) at room temperature. AC conductivity followed Johnson’s power law with a small-polaron tunneling conduction mechanism, while impedance spectroscopy confirmed non-Debye relaxation. This study also demonstrates that the KLNS5 sample achieves a significantly higher remanent polarization of 2.24 μC/cm² compared to 1.38 μC/cm² in KLN, indicating enhanced ferroelectric properties resulting from compositional modification.

Silicon (Si) is regarded as one of the most promising anode materials for next-generation lithium-ion batteries due to its exceptionally high theoretical capacity. However, its practical application remains limited by severe volume expansion and intrinsic low electrical conductivity, leading to electrode pulverization, unstable solid electrolyte interphase, and rapid capacity fading. Here, we develop a novel nano-silicon/edge-hydroxylated graphene (Si@EHG) composite synthesized via a potassium persulfate (KPS)-assisted high-energy ball milling strategy. This scalable and environmentally benign approach enables edge-selective hydroxylation of graphite without compromising its sp²-conjugated basal plane, thereby maintaining high electronic conductivity while introducing reactive –OH groups at the edges. The edge hydroxyls promote the formation of robust Si–O–C interfacial bonds with the native SiO_x layer, effectively enhancing interfacial adhesion, stabilizing the SEI, and enabling uniform lithium-ion transport. Among the composites, the Si@EHG-3% electrode exhibits the best performance, delivering a high initial discharge capacity of 3030.9 mAh·g⁻¹, 73.94% capacity retention after 100 cycles, and superior rate capability. Electrochemical impedance spectroscopy and lithium-ion diffusion coefficient analysis reveal that EHG incorporation significantly reduces charge transfer resistance and improves ion transport kinetics. This work demonstrates a rational and scalable interfacial engineering strategy based on edge-functionalized carbon materials, providing new insights for the design of high-capacity, durable silicon anodes for advanced lithium-ion batteries.

A major challenge in SnO₂-based NO₂ gas sensors is their limited sensitivity and selectivity at low operating temperatures. To address this, the present work employs plasma jet-assisted Co₃O₄ nanoparticle decoration as a simple, low-cost, and scalable strategy to enhance gas- ensing performance. In this study, tin oxide (SnO₂) thin films were prepared at 400 °C temperature by a simple spray pyrolysis. The films were then decorated with cobalt oxide (Co₃O₄) nanoparticles using an atmospheric plasma jet at different exposure times (5 and 10 min). X-ray diffraction (XRD) of the bare films revealed the coexistence of SnO₂ and SnO phases with variations in crystallite size observed after the nanoparticle decoration. Films exposed to a longer plasma treatment (10 min) exhibited an additional Co₃O₄ phase, confirming the successful deposition of cobalt oxide nanoparticles. FE-SEM images indicate the surface modifications by the appearance of nanoparticles whose number density increased with decoration time. FTIR spectra displayed the characteristic bands of tin oxide along with new absorption bands attributed to cobalt oxide. Optical absorption spectra demonstrated a red shift in the absorption edge following nanoparticle deposition. Gas-sensing measurements revealed a notable enhancement in NO₂ response after decoration, with the best performance achieved at a 5-min exposure time. The optimized sample exhibited a maximum sensitivity of nearly twice that of the pristine film toward 60-ppm NO₂ at 200 °C, while longer decoration times reduced performance. These results confirm the effectiveness and simplicity of atmospheric plasma jet nanoparticle decoration for environmental monitoring applications.

In this work, a quick solution combustion approach was used to successfully synthesise pure and 5 mol% gallium (Ga)-doped titanium dioxide (TiO₂) nanoparticles. In order to determine their suitability as photoanodes, the structural, morphological, and optical characteristics of the resulting materials were examined, and their performance in dye-sensitized solar cells (DSSCs) sensitized with Moringa oleifera leaf extract was evaluated. X-ray diffraction (XRD) confirmed the formation of the anatase phase, while transmission electron microscopy (TEM) revealed improved lattice contrast and particle dispersion in the Ga-doped TiO₂. UV–visible spectroscopy showed enhanced dye adsorption and light-harvesting capability for the doped samples, and these structural and optical modifications contributed to improved electron transport and reduced charge recombination. DSSCs based on Ga-doped TiO₂ achieved a power conversion efficiency of 3.7%, significantly higher than the 1.97% observed for undoped TiO₂. These results demonstrate that Ga doping effectively enhances the structural, optical, and photovoltaic performance of TiO₂ photoanodes, providing a sustainable strategy for environmentally friendly DSSCs.

This work investigates the influence of thermal annealing on the structural, optical, dielectric, electronic, and nonlinear properties of thermally evaporated Azure A chloride (AZACl) thin films. XRD results show improved crystallinity and preferential orientation with crystallite size increasing from 44 to 51 nm as the annealing temperature reaches 523 K. UV–Vis measurements reveal enhanced absorption and a distinct red shift in the Q- and B-band optical gaps, with E_g1 decreasing from 1.68 to 1.52 eV and E_g2 from 3.44 to 2.80 eV. Dispersion and dielectric analyses indicate an increase in the high-frequency dielectric constant, enhanced polarization effects, and longer dielectric relaxation time after annealing, reflecting improved molecular ordering and defect-related charge dynamics in the AZACl films. Optical and electrical conductivities also rise significantly, while the nonlinear susceptibility and nonlinear refractive index are enhanced, indicating improved nonlinear optical response. Gaussian 09 software was used to perform quantum-chemical calculations, including structure optimization and simulation of the absorption spectrum of AZACl. These results demonstrate that controlled thermal annealing is an effective route for tuning the optical and nonlinear optical properties of AZACl thin films, highlighting their potential for optoelectronic and photonic applications.

The research study exposes the consequence of annealing temperature and ZrO₂–ZnO composition ratio on co-precipitation-derived nanocomposites with emphasis on their potential for optoelectronic and photocatalytic applications. Nanocomposites with varying molar ratios of ZrO₂ and ZnO were synthesized and annealed at temperatures in the range 673 to 1173 K. XRD analysis revealed a crystalline transition of zirconia from tetragonal to monoclinic phase with increasing annealing temperature, along with the persistence of the hexagonal wurtzite structure of ZnO. Higher ZrO₂ content modified the surface morphology of ZnO, reducing nanoparticle aggregation and enhancing the effective surface area. EDS confirmed the targeted stoichiometry, whilst XPS demonstrated systematic binding energy shifts with increasing ZnO concentration. The increasing amount of ZnO in the nanocomposite is found to be altered the optical bandgap from 5.2 to 3.03 eV. Photoluminescent studies further revealed the formation of defects and modifications in electronic excitation levels, as a function of annealing temperature. Correlated colour temperature (CCT), varying from 4000 to 6000 K, and colour purity calculations conducted on the prepared nanocomposites, suggests potential for optoelectronic applications attributed to improved charge separation and surface properties. The synthesized composites demonstrated notable photocatalytic activity, with a maximum degradation efficiency and rate constant up to 77% and 0.00715 min⁻¹ respectively.

Dyes discharged from industrial units pose threats and dangers to both living organisms and the environment. Degradation of dyes to safe components is a benign approach to control or minimize their polluting effects. In this context, photocatalytic degradation by materials such as TiO₂ is a viable option because this process is driven by renewable solar energy. However, the photocatalysis suffers from relatively low efficiency due to limitations such as slow surface kinetics and higher recombination of charges. Herein, we demonstrate that glycerol treatment of TiO₂ offers dual advantages, namely morphological changes and metal-vacancy creation that lead to better efficiency for the dye degradation process. When 5% glycerol is used, the morphology transforms from particulate to nanoflakes, thereby leading to a significant improvement in the specific surface area from 3.7 to 7.9 m²/g. Further, ESR and XPS results confirm the creation of Ti vacancies, which may lead to defect states as well as spin polarization effects. Photodetection experiments confirm both the presence of defect states and longer recombination time of charge carriers in 5% glycerol-treated samples. Dye degradation experiment performed under a magnetic field shows an increase from 68 to 72% for pristine samples and glycerol-treated samples, respectively. This shows that the dye degradation process is influenced by both surface area enhancement and spin polarization induced reduction in recombination. Further, an increase in dye degradation efficiency in a magnetic field also indicates the probable influence of the Lorentz force in charge separation.

Conventional microwave-absorbing materials struggle to meet modern demands for ‘thinness, light weight, wide bandwidth, and strong absorption’ in complex electromagnetic environments. Furthermore, emerging applications require new functionalities, specifically low-frequency absorption and multi-band response. To address these challenges, this work designs and constructs a multi-mechanism synergistic absorbing system based on a rare earth-transition metal Y-Co (Y₂Co₁₇) alloy. The system is fabricated via heterogeneous deposition and thermal treatment to obtain ZnO@YCo composites. The results offer significant implications for the development of low-frequency and multi-band electromagnetic wave-absorbing materials. The main research contents and findings are as follows: A heterogeneous deposition method was employed to introduce needle-like ZnO heterostructures on the surface of YCo particles, followed by thermal treatment to optimize the absorption performance of ZnO@YCo composites. By adjusting the heat treatment temperature, the ZnO morphology was tuned. At 300 °C, the ZnO coating exhibited a well-defined structure with minimal agglomeration. The material demonstrated enhanced low-frequency absorption while retaining good performance in the high-frequency range (14–18 GHz). At a thickness of 6 mm, the minimum RL of ZnO@YCo reached − 5.86 dB at 5.6 GHz, outperforming the pristine YCo powders (RL > − 2.5 dB), thus exhibiting promising low-frequency absorption capabilities.

In this study, we report the synthesis of highly porous cadmium oxide nanostructures (CdO NSs) tailored for high-performance supercapacitor applications. Although CdO possesses promising physicochemical properties, its intrinsic limitation lies in its relatively low electrical conductivity, which restricts its practical use as a super capacitor electrode material. To address this challenge, we strategically engineered oxygen vacancies and incorporated silver (Ag) and activated carbon (AC) onto the CdO surface, effectively enhancing its electrical conductivity and electrochemical activity. The structural characterization of the synthesized CdO NSs revealed a highly porous framework with abundant active sites and well-defined diffusion pathways, facilitating efficient ion transport and charge storage during electrochemical processes. Electrodes fabricated from the optimized CdO-based composites, namely Ag@CdO and AC/Ag@CdO, exhibited an impressive specific capacitance of 752.55 F g⁻¹ and outstanding cycling stability, retaining 98.53% of their initial capacitance after 1000 continuous charge–discharge cycles at a current density of 1 A g⁻¹. These findings underscore their strong potential as robust and efficient electrodes for next-generation super capacitor devices. Furthermore, the facile synthesis route employed in this work offers a cost-effective and time-efficient alternative to complex fabrication procedures, eliminating the need for elaborate composite architectures while substantially improving the electrochemical performance of CdO-based materials. A series of multifunctional nanocomposites—CdO, Ag@CdO, and AC/Ag@CdO—were fabricated via a straightforward co-precipitation process and systematically characterized using XRD, FT-IR, UV-DRS, PL, FT-Raman, FE-SEM, HR-TEM, XPS, and EDX. XRD confirmed progressive by Aruna Subramanian https://doi.org/10.1007/s10854-025-15631-z

The unique size-dependent structural and physical properties of Cr doped spinel ferrites have garnered significant attention due to their wide-ranging applications. In this work, CoCrₓFe_2-xO4 (x = 0.0, 0.5, 1.0, 1.5, and 2.0) nanoparticles were synthesized using the citrate–gel auto-combustion method and sintered at 700 °C. XRD analysis confirmed a pure cubic spinel phase for all samples, with the lattice parameter decreasing slightly from 8.3862 Å to 8.3835 Å as chromium content increased. HRTEM imaging revealed predominantly spherical particles with an average grain size of approximately 40 nm. Magnetic characterization showed a significant decrease in saturation magnetization (Ms) from 41.74 emu/g for x = 0.0 to 1.37 emu g⁻¹ for x = 2.0, representing a reduction of ~ 96.7%, while the magnetic moment per formula unit decreased from 1.72 to 0.21 μB. Conversely, the coercivity (Hc) exhibited an overall increase relative to the doped samples, peaking at 1303.8 Oe for the pure cobalt ferrite. Dielectric studies indicated that the dielectric constant (ε’) and loss tangent (tanδ) decreased with increasing frequency, following the Maxwell–Wagner interfacial polarization model. Specifically, ε’ values for x = 0.0 dropped from approximately 1500 to near-constant values at higher frequencies. AC conductivity (σ_AC) was found to rise with frequency, consistent with the small polaron hopping (SPH) mechanism. These results demonstrate that Cr³⁺ substitution effectively tunes the magnetic and electrical response of cobalt ferrites for multifunctional applications.