Journal of Materials Science: Materials in Electronics最新文献

As a macromolecular substance, cellulose is susceptible to the formation of interaction forces between its chains, which ultimately result in the generation of crystalline regions. In this paper, the reversible dehydrogenation reaction of ascorbic acid is employed, whereby the combination of dehydroascorbic acid and the hydroxyl group on the molecular chain of methylcellulose forms hydrogen bonding with the purpose of occupying the hydroxyl group on the molecular chain and inhibiting the formation of hydrogen bonding between the chains, thus eliminating the crystalline zone of methylcellulose. The alteration of hydrogen bonding and the elimination of the crystalline region were identified through the utilization of Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). Concurrently, a copper paste is formulated. The addition of copper results in the intensification of the oxidation of ascorbic acid at temperatures in the range of 200 °C. This leads to the formation of oxalic acid, which subsequently forms copper oxalate with copper at high temperatures. This process then enters the ascorbic acid colloid, forming a conductive channel. In accordance with the principles, a low-temperature sintered copper paste was devised and manufactured, exhibiting a high viscosity recovery rate (75.8%), high adhesion, low resistivity (4.2*10⁻⁶Ω*cm), and objective aspect ratio (0.28) after screen printing.

The demand for sustainable energy storage materials drives the quest for eco-friendly, cost-effective alternatives to conventional electrodes, which frequently depend on hazardous or non-renewable substances. Hence, metal nanoparticles (Cu, Ni, and CuNi alloy) and their nanocomposites with elastin fibril (EF) and elastin monomer (EM) proteins have been synthesized by the chemical reflux method to explore their suitability for energy storage device applications. Among all the nanoparticle-protein combinations, the Cu-EM nanocomposite-based electrode shows the maximum specific capacitance (88 F g(^{-1})), areal capacitance (176 mF cm(^{-2})), and maximum energy density (12 Wh kg(^{-1})) at the applied scan rate of 10 mV s(^{-1}), according to the cyclic voltammetry results. According to electrochemical impedance spectroscopy, the same nanocomposite showed the least charge transfer resistance (0.9 (Omega)) and the least solution resistance (0.9 (Omega)). The cyclic stability performance of the Cu-EM electrode was measured through the galvanostatic charge discharge tests. The device demonstrates excellent capacitance retention of 80.2% after the 8000(^{th}) cycle. Thus, the Cu-EM nanocomposites display the best electrochemical performance among all the synthesized samples. It is inferred that the incorporation of Cu nanoparticles in the composite facilitates a fast electron transfer inside the active material, leading to an enhancement in the specific capacitance. The values of the electrochemical parameters, as exhibited, are acceptable for energy storage devices. The Cu-EM nanocomposites are flexible due to the presence of the protein. Thus, these nanocomposite-based electrodes can find applications in flexible energy storage devices. Furthermore, the synthesized material more closely adheres to cost-effective and environmental requirements.

High efficiency (η) is urgently desired for electronic energy storage devices. In this work, an extremely high energy storage efficiency (~ 99.5%) and energy storage density of 2.83 J/cm³ are achieved in lead-free relaxor ferroelectric (1–x)(0.9BaTiO₃–0.1BiMg_0.5Ti_0.5O₃)-xBi(Mg_0.5Sn_0.5)O₃[(1–x) (0.9BT–0.1BMT)–xBMS] ceramic (x = 0.09). Excellent temperature stability with a variation of η less than 1.5% is also obtained in a wide temperature range from 30 to 150 °C. Temperature dependence of the dielectric permittivity of (1–x)(0.9BT–0.1BMT)-xBMS exhibits a typical dipolar-glass-like relaxor ferroelectric behavior. As a result, the ultra-high efficiency of the ceramic is attributed to the weak-coupling polar nanoregions (PNRs) which are analyzed using the Vogel-Fulcher formula and phenomenological statistical model. These results not only help to understand the origin of high efficiency in the (1–x)(0.9BT–0.1BMT)-xBMS system but also provide an effective approach to improve the comprehensive properties of other lead-free ceramic systems used in next-generation power capacitors.

Manganese-based and vanadium-based compounds possess abundant valence states, making them highly promising for application in aqueous zinc-ion batteries. In this work, the manganese and vanadium-based composite material VO₂@MnCO₃@Mn₃N₂ was synthesized via the hydrothermal method. Through electrochemical performance testing, the optimal vanadium-to-manganese ratio and urea addition amount were selected. The study also compared the differences in electrochemical performance of the composite materials synthesized under various hydrothermal conditions and calcination conditions. The material with the best electrochemical performance delivered a maximum capacity of 436.6 mAh/g at the current density of 50 mA/g, and a maximum capacity of 325.4 mAh/g at the current density of 100 mA/g. Physical property characterization reveals that the composite material synthesized under optimal conditions consists of cube shapes with protrusions and nanoparticles, both of which are uniformly distributed within the composite. The nanoparticles are composed of both vanadium-based and manganese-based compounds. The Infrared spectroscopy, Raman spectroscopy and XPS analysis confirm that the valence states of the elements are consistent with those of VO₂ and MnCO₃. Refined XRD fitting shows that the main components of the composite material are VO₂, MnCO₃, and Mn₃N₂, with a molar ratio of vanadium to manganese at 1:1 and VO₂ accounting for 50% of the composition.

This study investigates the EMI shielding performance, mechanical, and dielectric properties of composite materials reinforced with waste silk fibers and biochar extracted from jackfruit rags, utilizing temperature aging techniques. Vinyl ester resin, selected for its reliability and water-resistant properties, served as the matrix material, while biochar from jackfruit rags and silk mats provided reinforcement. The biochar was effectively produced through a pyrolysis process at 750 °C, and the composite fabrication was achieved using a hand layup method followed by curing and post-curing processes. Among the tested specimens, VSB2, which contains 3-vol.% biochar, demonstrated superior mechanical properties, including a tensile strength of 131 MPa and a flexural strength of 152 MPa, significantly outperforming the base specimen V. The specimen also exhibited enhanced dielectric properties, with post-aging dielectric values of 5.8, 4.7, 3.7, and 2.6 at 8 GHz, 12 GHz, 16 GHz, and 18 GHz, respectively, indicating strong interaction between the biochar and the vinyl ester matrix. VSB2 also showed the highest EMI shielding effectiveness, with total shielding values of 31.5, 47.25, 63, and 68.25 dB at the respective frequencies, reflecting optimal absorption and reflection due to the well-dispersed biochar. The SEM analysis provided crucial insights into the microstructural enhancements responsible for these improvements. The uniform dispersion of biochar nanoparticles, and the improved interfacial bonding between fibers and the matrix, significantly contributed to the mechanical strength and durability of VSB2. Additionally, the study highlighted the positive impact of aging at 50 °C for 120 days, which further improved the dielectric and EMI shielding properties, confirming the composite’s stability and suitability for applications in high-temperature environments.

The aromatic organic 4-dimethylaminopyridine single crystals were grown by the slow evaporation solution growth method. The unit cell parameters of the grown 4-dimethylaminopyridine crystal were studied by single crystal and powder X-ray diffraction (PXRD) studies. The Fourier transform infrared (FTIR) and FT-Raman spectral analyses were used to identify the functional groups of the grown crystal. The UV–Vis–NIR studies reveal that the grown crystal cut-off wavelength is around 345 nm and the band gap was measured as 3.15 eV. The optical parameters such as the absorption coefficient (α), extinction coefficient (K), reflectance (R), refractive index (n), Urbach Energy (E_U)_, Steepness parameter (σ) and Electron–Phonon interaction (E_e–p) were calculated. The photoluminescence (PL) analysis was carried out, which shows the high intensity emission peak observed at 545 nm. The thermal analyses reveal that the grown crystal melting point is 115 °C and the decomposition point is 205 °C. The kinetic and thermodynamic parameters such as the activation energy, enthalpy, entropy and Gibbs free energy were calculated from the TGA data using the Coats–Redfern, Horowitz–Metzger and Piloyan–Novikova methods. The dielectric measurements were carried out with different frequencies at various temperatures using parallel plate capacitor method and the electronic parameters were also calculated. The activation energy was calculated from Arrhenius plot. The Vickers micro-hardness studies were performed to analyse the mechanical strength of the grown crystal. The work hardening coefficient, stiffness constant, yield strength, fracture toughness and brittleness were calculated. The nonlinear optical properties of the grown 4-dimethylaminopyridine single crystal were measured by the Z-scan technique.

In this paper the structural, dielectric and electrical conduction behaviour of Ca_6-xNa₂Y₂(SiO₄)₆(Cl)₂: xGd³⁺ (x = 0–0.05 mol%) chlorapatites prepared via hydrothermal process based on liquid–solid solution has been reported. The emergence of a monoclinic phase with P2₁/c space group is confirmed by x-ray diffraction (XRD) investigation. Space charge polarization is the predominant mechanism, according to dielectric studies that depend on frequency and temperature. Grain and grain boundary contributions to the thermally induced relaxation process are demonstrated using complex impedance spectroscopy. For all compositions, resistance of grain and grain boundaries exhibited negative temperature coefficient of resistance (NTCR) behaviour i.e., it decreases as temperature rises. The Nyquist plots indicated that the synthesized compounds appear non- Debye in nature. For all prepared compounds, the electrical modulus spectroscopy demonstrates that the electrical transport phenomenon occurs through both, short-range and long-range hopping of charge carriers. As frequency increases, the a. c. conductivity also increases, indicating that the compounds obey Jonscher’s power law.

High energy conversion sensors are a special kind of luminous material that plays an important role in fields including medical diagnostics, physics, and radiation detection. A growing trend in this field is the development of flexible, wearable sensors, fabricated on substrates like fabrics and polymers, which offer the flexibility needed to undergo mechanical deformation caused by the human body. In the current research, flexible Cerium doped Tungstate Oxide/Titanium Dioxide (WO₃/TiO₂: Ce) nanocomposite film was fabricated by a low-cost method based PVA matrix. Several techniques were used to characterize the produced nanopowders and study about their structural, morphological, and optical features. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and Raman all showed characteristic peaks for components relating to WO₃ and TiO₂ in the nanocomposite. Results from XPS confirmed strong interactions between WO₃ and TiO₂, with distinct binding energies indicative of specific oxidation states, including Ti⁴⁺, W⁶⁺, Ce⁴⁺, and Ce³⁺. Nanoparticles, with an average particle size of 60–65 nm, were uniformly distributed in the matrix according to the FESEM and TEM images. The behavior of alpha particles from a ²⁴¹Am source was analyzed through nanopowders and PVA polymer using Monte Carlo simulation, with optimal thicknesses confirmed by FESEM analysis. The optical characteristics were investigated using photoluminescence spectroscopy (PL), and ion beam-induced luminescence (IBIL). The produced nanocomposites were evaluated for their responses to ionizing radiation under a ²⁴¹Am alpha source; Prepared WO₃/TiO₂: Ce flexible nanocomposite film showed high-sensitivity (89.47%) to alpha irradiation and strong green emission at room temperature compared with pure WO₃ and TiO₂ films. Our findings highlight WO₃/TiO₂: Ce nanocomposite's potential as a promising optical flexible sensor for high-energy conversion in radiation detection and optical applications.

Metal–organic framework (MOF) compounds are particularly attractive as promising advanced functional materials in energy storage and conversion. However, they exhibit limited electrochemical properties due to their inherent instability and poor electrical conductivity. Herein, a high-conductive electrode material of trimetallic Co/Ni/Fe-MOF was prepared using a solvothermal method. The morphology, specific surface area, and electrochemical properties of the Co/Ni/Fe-MOF were measured. Experimental results show that Co/Ni/Fe-MOF materials have a mesoporous structure and a large available specific surface area of 17.04 m²·g⁻¹. When the discharge current density is 1 A·g⁻¹, the specific capacitance of Co/Ni/Fe-MOF is as high as 2290 F·g⁻¹. An asymmetric supercapacitor device was assembled using Co/Ni/Fe-MOF material as the positive electrode and activated carbon (AC) as the negative electrode. The Co/Ni/Fe-MOF//AC asymmetric supercapacitor has a power density of 7500 W·kg⁻¹ and an energy density of 132.3 Wh·kg⁻¹ in a potential window of 1.5 V. The excellent electrochemical properties of Co/Ni/Fe-MOF make it a wide application prospect as an electrode material for supercapacitors in the energy storage field.

Copper sulfide (CuS), under the category of metal sulfide, remains as promising anode for Sodium-ion Batteries (SIBs) with a theoretical capacity of 560 mAhg⁻¹. CuS suffers from polysulfide formation, severe capacity fading upon cycling. To address these issues addition of bio-carbon is sought as a measure in this work. A porous carbon has been successively synthesized from sodium alginate source with a specific surface area of 38.78 m²g⁻¹ and an average pore volume of 3.40 nm. The addition of prepared porous carbon to copper sulfide (CuS) enhances stability in the electrochemical performance with the value of 442 mAhg⁻¹ being the initial discharge capacity observed at a current density of 100 mAg⁻¹ over 500 cycles. The technology in performing solid-state reaction is well established and does not demand high infrastructure for atmospheric control thus facilitating large-scale production. Therefore, this work throws light on the benefit of adding bio-carbon to CuS.