Journal of Materials Science: Materials in Electronics最新文献

Detailed investigation on microstructural, phases, morphological and dielectric behavior of polyvinylidene fluoride (PVDF) and its nanocomposites filled with MoS₂ and h-BN as 2d nanofillers has been carried out. Modifications in surface morphology with reduced spherulitic crystals size and lower crystallinity have been observed with the addition of nanofiller. Non-polar to polar phase conversion and excellent dielectric properties with the addition of nanofillers were experimentally measured over a temperature (80–473 K) and frequency range (10 Hz to 8 MHz). Strong interfacial polarization and interaction between PVDF dipoles and filler nanoparticles delays the relaxation process, typically showing a non-Debye behavior and were analyzed using the Havriliak–Negami function. To suppress electrode polarization, which typically appears at low frequencies obscuring the relaxation processes occurring in the low-frequency regime, electric modulus formulism was used and analyzed by using the modified Kohlrausch–Williams–Watts function.

Dexterous semi-organic Glycine doped Copper Sulphate (GDCS) single crystal was produced by slow evaporation solution growth method. Single crystal X-ray diffraction studies were used to authorize the crystal structure. It shows that the grown GDCS crystal belongs to the space group P1 with a triclinic crystal system and the found lattice parameters are a = 5.9758(14) Å, b = 6.1295(15) Å, c = 10.751(3) Å, α = 77.446(8) °, β = 82.358(8) °, γ = 72.691(7) °, volume = 365.99(15) ų. The interaction of characteristic functional groups was approved by FTIR and FT-Raman spectra. The optical properties were studied by UV–Vis-NIR and fluorescence analyses. The optical parameters such as optical band gap (4.33 eV), Urbach energy (4.971414 eV), steepness parameter. (4.7321 × 10^–3) and electron–phonon interaction (1.4088178 × 10²) were calculated. The observation of maximum intensity peak for the GDCS crystal at 545 nm pointed out green fluorescence emission. The third-order nonlinear optical properties of the synthesized crystal were analysed using the Z-scan technique. The third-order nonlinear optical parameters of GDCS single crystal such as absorption coefficient, nonlinear refractive index, third-order nonlinear optical susceptibility and second-order molecular hyperpolarizability have been computed. The result shows that the grown GDCS single crystal may be used for applications of holographic recording and two-wave mixing. The thermal lenience and decomposition mechanism of the grown compound was examined by simultaneous TG–DTA analysis. The kinetic parameters such as activation energy, frequency factor, entropy, enthalpy and Gibbs free energy were calculated using Coats–Redfern method. The dielectric characteristics of the synthesized crystal was studied by dielectric analysis. The dielectric parameters of the grown crystal such as plasma energy (18.656 eV), Penn gap (4.2042 eV), Fermi energy (14.5865 eV) and electronic polarizability have been calculated. The crystalline morphology was inspected by SEM analysis. It was noted from the SEM images that the surface of the produced crystal is smooth and contains of uniformly dispersed clusters. Its elemental composition was confirmed by EDAX analysis. In the EDAX spectrum, the occurrence of Cu, S and O intense peaks confirm the presence of copper, sulphur and oxygen in the grown GDCS single crystal respectively. The antibacterial activity of GDCS crystal against strains Pseudomonas aeruginosa, Serratia marcens and Staphylococcus aureus have been analysed. The antifungal activity of the sample against strains Candida albicans, Aspergillus niger and Aspergillus flaves were tested.

In this study, we investigate the photovoltaic properties of the Au/Si/CuSbS₂/Au junction thin films grown at different substrate temperatures using vacuum thermal evaporation. The GLAD technique was used to tilt the substrate at an angle of 60°. Our results show that increasing the substrate temperature increases the photovoltaic activity compared to films deposited at room temperature. The CuSbS₂ deposited at 150 °C showed the highest photovoltaic conversion efficiency(η) of 3.11%. These results highlight the potential of CuSbS₂ for photoconductive applications and open new avenues for further research in this field. Key diode parameters, including ideality factor (n), series resistance (Rs) and saturation current density (Js), were extracted from J-V measurements of (Au/Si/CAS-2/Au) structures fabricated at different substrate temperatures (RT, 150 °C and 200 °C). The analysis of J-V characteristics under 1000 W/m² illumination allowed the determination of key solar cell parameters, including short circuit current density (J_sc) of 1.21, 7.54, and 0.80 mA/cm², open circuit voltage (Voc) of 0.95, 1.33, and 0.58 V, fill factor(FF) of 0.32, 0.33, and 0.19, and solar conversion efficiency (η) of 0.37, 3.11, and 0.10% for different temperatures, respectively.

The direct generation of hydrogen (H₂) from seawater offers a sustainable pathway for renewable fuel production. Here, we report a spherical-clustered molybdenum oxide/intercalated chloride–poly(N-methylpyrrole) (MoO₃/Cl–PNMP) photocathode synthesized via a controlled chemical polymerization route and evaluated for photoelectrochemical (PEC) hydrogen evolution from seawater. The nanocomposite exhibits well-defined crystallinity and a narrow optical bandgap of approximately 1.32 eV, enabling efficient solar energy harvesting and charge transfer. Morphological analysis reveals uniformly distributed nanospheres (~ 30 nm) aggregated into larger clusters that provide enhanced surface area and light absorption across a broad spectral range. The PEC response of the MoO₃/Cl–PNMP electrode was systematically examined under various electrolytic conditions, including natural Red Sea water and synthetic seawater of comparable ionic composition, as well as under incident wavelengths spanning 340–730 nm to simulate full-spectrum solar irradiation. Hydrogen generation rates, determined by Faraday’s law, reached 1.2 µmol h⁻¹ cm⁻² in natural seawater and 1.1 µmol h⁻¹ cm⁻² in synthetic media. These results highlight the strong potential of seawater as an abundant, cost-free electrolyte and underscore the promise of the MoO₃/Cl–PNMP photocathode as a stable and efficient platform for solar-driven hydrogen production. This work advances the design of molecularly engineered photoelectrodes for sustainable energy conversion and contributes to the ongoing transition toward clean hydrogen technologies.

This study investigates the impact of erbium (Er3⁺) doping on the structural, thermoelectric, and electrical properties of titanium dioxide (TiO₂) nanoparticles synthesized via a straightforward ball milling approach. Pure TiO₂ and Er-doped TiO₂ (1%, 2%, and 3% Er) nanocrystalline powders were prepared and characterized using X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), density measurements, Seebeck coefficient analysis, and DC conductivity measurements. XRD and HRTEM results confirmed the formation of the anatase TiO₂ phase and the successful incorporation of Er3⁺, leading to a reduction in crystallite size (from 18.33 nm for pure TiO₂ to 14.19 nm for 3% Er-TiO₂) and an increase in lattice strain with higher doping concentrations. Density increased with doping, while molar volume decreased. Thermoelectric tests showed that pure TiO₂ and the sample with 1% Er-doping conducted electricity in a p-type manner, but at higher temperatures, the samples with 2% and 3% doping showed both p-type and n-type conduction. Crucially, Er3⁺ doping significantly enhanced the DC electrical conductivity and thermoelectric power (TEP) factor compared to undoped TiO₂. The conduction mechanism in the high-temperature region was identified as non-adiabatic small polaron hopping (SPH), with the improved conductivity attributed mainly to increased hopping carrier mobility. These findings highlight the effectiveness of Er3⁺ doping via ball milling in tailoring the properties of TiO₂ for potential thermoelectric applications.

Cobalt(II) coordination compound [(phenanthroline-κ²N,N′)-bis(6-phenylpyridine-2-carboxylate-κ²N,O)cobalt(II)] H2O (PPPC) was produced in a mixed water–ethanol medium using a controlled slow-evaporation method, producing optically transparent and morphologically stable crystals appropriate for the assessment of multifunctional properties. An orthorhombic P2₁2₁2₁ structure with a deformed octahedral Co(II) coordination environment was established by single-crystal X-ray diffraction. Optical studies showed exceptional transparency throughout the visible spectrum and a clearly defined absorption edge at 336 nm, suggesting suitable for photonic components. Dielectric research revealed a distinctive drop in loss and permittivity with frequency, which is consistent with little space-charge contribution and strong insulating behaviour. While the figure of merit showed excellent responsivity in the 42–45 °C region, indicating stable thermally induced polarisation dynamics, pyroelectric investigations showed a distinct peak near 50 °C. Switchable polarisation and weak ferromagnetic ordering were verified by ferroelectric and magnetic hysteresis tests, confirming PPPC’s status as a polar multifunctional material. A second-harmonic output of 71.32 mV, roughly three times that of KDP, was obtained using nonlinear optical characterisation using the Kurtz–Perry method. Ultrafast excitation generated broadband terahertz radiation through optical rectification. PPPC is positioned as a promising coordination crystal for new optoelectronic, nonlinear optical, and multifunctional device applications according to these combined structural and functional findings.

In this study, a sustainable triboelectric nanogenerator (TENG) was developed using biodegradable polylactic acid (PLA) and a non-biodegradable carbon fiber-reinforced PLA matrix (PLA-CF) fabricated via fused deposition modeling (FDM), coupled with a water-soluble polyvinyl alcohol (PVA) film prepared through the solvent casting method. The use of biodegradable and environmentally friendly polymer materials aims to address the ecological concerns associated with conventional non-biodegradable polymers used in TENG devices. Carbon fiber incorporation enhanced the triboelectric properties of PLA by improving its surface roughness, electron affinity, and mechanical strength. The fabricated materials were characterized using X-ray diffraction spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and water contact angle measurements. Mechanical strength was evaluated using a universal testing machine. The assembled TENG, comprising PLA/PLA-CF as the negative triboelectric layer and PVA as the positive triboelectric layer, demonstrated stable voltage output capable of lighting LEDs and functioning as a self-powered touch-counting sensor. This work highlights the potential of FDM-based polymer composites for efficient energy harvesting and interactive sensing applications.

This research investigates the effects of nitric acid (HNO₃) treatment on the structural, morphological, and electrochemical properties of Bi₂WO₆ nanosheets. The monoclinic structure of Bi₂WO₆ was verified by the X-ray diffraction (XRD) analysis. Morphological observations were made using Field emission scanning electron microscopy (FE-SEM). TEM, HRTEM and SAED confirm the formation of highly crystalline Bi₂WO₆ nanosheets with controlled morphology influenced by HNO₃ treatment. The FTIR spectrum showed absorption peaks 450 cm⁻¹ and 1000 cm⁻¹, due to the stretching and bending vibrational frequencies of Bi–W–O bonds. The Raman spectroscopy showed an active W–O stretching mode at 889 cm⁻¹. In a 3 M KOH aqueous electrolyte, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to evaluate the samples' electrochemical performance. Compared to earlier reported Bi₂WO₆ electrodes (generally 150–350 Fg⁻¹), the HNO₃ treated Bi₂WO₆ nanosheets exhibits relatively enhanced performance, achieving 422–449 F g⁻¹, resistance of 0.91 Ω, coulombic efficiency was 99.9%, and remarkable cycling stability (93.9% retention even after 5000 charge–discharge cycles), comparable with high-performing metal oxide supercapacitor electrodes.

Mixed halide perovskite films are important for various optoelectronic applications. This study involves the synthesis and characterization of mixed halide perovskite films MAPbBr_xI_3-x (where x = 0, 1, 2, 3), by maintaining a fixed 1:1 molar ratio of the methylammonium halide and lead halide in spin coating. The films were fabricated via the spin coating method on glass substrates. UV–visible absorption spectroscopy revealed a tunable optical bandgap ranging from 1.57 (MAPbI₃) to 2.27 eV (MAPbBr₃), corresponding to absorption edges that shifted from 788 to 547 nm as the bromine content increased. X-ray diffraction confirmed high crystallinity, particularly in MAPbBr₂I, which exhibited the most intense and sharp peaks. SEM analysis revealed varied morphologies influenced by the halide composition, with the fixed equimolar ratio resulting in well-defined and uniform crystal structures. Notably, MAPbBr₂I displayed a smooth and uniform surface, indicating superior film quality and minimized defect density. FTIR and Raman spectroscopy provided insights into molecular interactions, vibrational modes, and structural properties. This study uniquely highlights how maintaining a consistent organic-to-inorganic ratio influences the optical, structural, and morphological properties of mixed halide perovskites. The findings suggest that MAPbBr₂I, with its optimal crystallinity, bandgap, and morphology, is a promising candidate for optoelectronic applications.

Through capacitance–voltage and triangular voltage sweep (TVS) measurements, mobile positively charged ions were observed in structures with as-deposited amorphous Ta₂O₅ and crystalline β-Ta₂O₅ layers obtained after subsequent annealing of amorphous layers at 950 °C in O₂ and Ar atmospheres. Analysing the shift of the characteristic TVS peak corresponding to these defects at different temperatures, we determined the activation energy for ion drift to be 360 meV and 380 meV in amorphous and crystalline Ta₂O₅ layers, respectively. Ion-coupled mass spectrometry (ICP-MS) measurements revealed that Na was the predominant defect in the as-deposited Ta₂O₅, with its intensity significantly surpassing that of other defects. Consequently, we attribute the positively charged defects to interstitial Na⁺ ions, which are likely to be incorporated into the targets used for deposition.