Journal of Materials Science: Materials in Electronics最新文献

In this study, we present a novel composite electrode based on nitrogen and sulfur co-doped carbon quantum dots (NSCQDs), synthesized using Senna auriculata biomass, a natural and renewable source. X-ray diffraction (XRD) analysis revealed high crystallinity of the synthesized material, with the NSCQD signature being indistinct due to irregular stacking and low concentration. Scanning electron microscopy (SEM) confirmed the formation of larger spherical hybrid clusters, attributed to the incorporation of NSCQDs. We analyzed the composite electrode using cyclic voltammetry (CV) and differential pulse voltammetry (DPV), which revealed efficient electron transfer, minimal background current, and a broad detection range. The DPV analysis exhibited excellent linearity and sensitivity, with a proportional decrease in peak currents over a dopamine concentration range of 20–7000 nM. The sensor achieved a high sensitivity of 0.01521 µA/nM and a low detection limit of 0.1 nM. The modified electrode also demonstrated low noise and high reproducibility, underscoring its practical viability. This sustainable technique not only adheres to green chemistry principles, but it also improves the electrochemical characteristics of NSCQDs, making them extremely useful for dopamine sensing. The combination of NSCQDs and cobalt hexacyanoferrate (CoHCF) produced a composite electrode with high selectivity and sensitivity. The NSCQD/CoHCF composite electrode outperforms many existing sensor technologies and holds significant promise for reliable and efficient dopamine detection in real-world applications.

Photocatalytic CO₂ reduction for solar fuel production has garnered significant attention due to its potential to address both the energy crisis and CO₂ pollution. In this study, ZnCo₂O₄-rGO hybrid catalyst, specifically ZnCO₂O₄/10% rGO and ZnCo₂O₄/20%rGO, were designed by ultrasonic-assisted hydrothermal method for photocatalytic CO₂ reduction to address energy and environmental challenges. We evaluated the photocatalytic reduction ability of CO₂ to methanol and observed that incorporating rGO significantly reduced the recombination of photogenerated electron–hole pairs, thereby enhancing the photocatalytic activity of ZnCo₂O₄. Among the synthesized photocatalysts, ZnCo₂O₄ with 20% rGO exhibited the highest photocatalytic performance, attributed to its narrow band gap and efficient charge mobility. The ZnCo₂O₄/20%rGO heterogeneous photocatalyst maintaining its effectiveness through five consecutive reaction cycles without observable degradation in catalytic activity. ¹³CO₂ isotopic experiment validated that the produced methanol was from the photoreduction of CO₂. This result demonstrates that after 10 h of irradiation, the yield of methanol was 145 µmol/g, which is significantly higher than that obtained with pristine ZnCo₂O₄ (66.2 µmol/g) and previously-reported photocatalysts. This underscores that ZnCo₂O₄/20% rGO is a simple, efficient, and promising visible-light-driven photocatalyst for the photoreduction of CO₂ into solar fuels.

This work reports the growth and deposition of pure and Mg-doped nickel ferrite thin films (Ni_1-xMg_xFe₂O₄, x = 0.0,0.1,0.2,0.3,0.4 and 0.5) using spray pyrolysis technique. The thin films were deposited on clean and ultrasonicated pre-heated glass substrate. The structural characterizations were made using X-ray diffraction technique (XRD). All the thin films possess single-phase cubic spinel structure, as evidenced from the XRD analysis. The crystallite size was evaluated using Scherrer formula and found to be vary in the range of 11 nm to 21 nm. The structural parameters like lattice constant (a), unit cell volume (V), X-ray density (d_x), micro strain (ε) and dislocation density (δ) were obtained and their variation with Mg content is discussed. Lattice constant and unit cell volume increase with Mg content x, X-ray density decreases with Mg content x, and the other structural parameters do not show any systematic trend. The surface morphological observations were carried out using Field emission scanning electron microscopy technique (FE-SEM). The spherical grains with average grain size between 26 and 41 nm were observed. The FTIR spectra recorded at room temperature show two metal oxygen absorption bands within the range 400 cm⁻¹–600 cm⁻¹. Raman spectra reveal five active modes namely T₂g (3), Eg, A₁g characterizing the spinel structure. With Mg doping, the Raman modes slightly shifted. The optical properties were studied using UV–Visible spectroscopy technique. The band gap energy values obtained from Tauc plot vary between 1.61 eV and 1.90 eV. I–V studies reveal the ohmic nature showing high values of resistivity. The obtained results are useful for photocatalytic degradation and gas sensing application.

This paper presents a novel additively manufactured antenna array on a flexible polymeric substrate for conformal mobile applications. The antenna consists of two identical z-shape patch elements integrated with symmetrical arrangements and right-angle ground assemblies to converge the dispersed radiation pattern for gain improvement. For planar feeding and fabrication, the antenna is fed with a coplanar waveguide and, horizontal defected ground structures are used in the patch to achieve multiband characteristics. The prototype antenna, fabricated with silver nanoparticles (AgNPs) using precision piezoelectric inkjet-printing technique, exhibited operation across five different frequency bands: 0.58–0.83 GHz, 1.39–1.58 GHz, 2.40–2.43 GHz, 2.88–3.52 GHz, and 4.93–5.15 GHz, covering mobile radios, GPS, UMTS, Wi-Fi, ISM, Bluetooth, WLAN, WiMAX, and sub-6 GHz 5G applications. Surface morphological studies of deposited conductive pattern of silver nanoparticles are also evaluated to confirm its smooth and uniform deposition. The antenna demonstrates an omnidirectional pattern with a peak gain of 12 dBi at 3.21 GHz and a measured impedance bandwidth of 640 MHz that show a good agreement with the simulation. The prototype antenna is also tested under bent conditions (radius of 3, 4, and 5 cm) and, the measured performance depicts apart from the minor shift in S11, it still performs sufficiently well. Comparison with existing literature reveals a significant improvement in gain, making this antenna superior in performance. The antenna’s robust performance under deformation, combined with its high gain and multiband capabilities, makes it excellent candidate for wearable electronics and conformal wireless mobile communication applications. This work paves the way for future advancements in flexible and high-performance antennas for next-generation wireless technologies.

In this study, we used a one-step laser ablation method to combine In₂O₃ colloidal nanoparticles with multi-walled carbon nanotubes (MWCNTs) to create an In₂O₃ NPs-MWCNTs heterostructure for photodetectors. X-Ray Diffraction (XRD) analysis of the prepared samples revealed that the In₂O₃ NPs/MWCNTs nanostructure contained graphite peak at the (002) plane and In₂O₃ NPs crystalline peaks which are indexed to body-centred cubic phase. Transmission electron microscope (TEM) investigation revealed that In₂O₃ nanoparticles have a spherical shape nanoparticle with an average size of 20 nm, and 33 nm for In₂O₃ NPs -MWCNTs nanostructure. UV–Vis test showed that the optical energy gap of the In₂O₃ NPs decreased from 3.2 to 2.7 eV after incorporating CNTs. The I–V characteristics for the In₂O₃ NPs/Si and In₂O₃ NPs-decorated MWCNTs/Si photodetector were investigated under both dark and illumination cases. The responsivity of the In₂O₃ NPs/Si photodetector showed an increase from 0.43 to 1.15 A/W after introducing CNTs at a wavelength of 450 nm. The fabricated photodetector showed a high sensitivity for Vis–NIR detection. The limit detection of In₂O₃ NPs -MWCNTs/Si photodetector was determined to be 3.39 × 10¹¹ Jones at 450 nm.

In this work, ternary zinc sulphoselenide (ZnSSe) thin films were prepared using a cost-effective chemical technique on glass substrates by varying the deposition period at a bath temperature of 70 °C. The X-ray diffraction analysis revealed the nanocrystalline nature of the films, with a cubic zinc blende structure and a preferential orientation along the (111) plane. The crystallite sizes increase from 17 to 28 nm with an increase in deposition time. The field emission scanning electron microscope micrographs displayed uniformly distributed spherical nano-shaped grains across the substrate. Energy-dispersive X-ray analysis was used to obtain the chemical composition of the films. The optical analysis showed that all the films exhibit 70%–80% transmittance, and the optical energy band gap decreases from 3.23 to 3.16 eV with increasing deposition time. The observed intriguing properties of ZnSSe thin films prove their importance in a wide range of optoelectronic device applications.

Referring to the concept of overshoot in automatic control principle, this paper proposes a novel random vibration lifetime prediction model based on traditional Miner’s rule, which accounts for the transient response due to changes in the vibration amplitude of the input excitation. Additionally, a time-domain method for applying this model is introduced and employed to evaluate the random vibration lifetime of metal hermetic sealing structure. The power spectral density (PSD) of the response stress, obtained from finite element analysis (FEA) under random vibration, is converted into multiple time-history datasets through phase randomization and inverse fast Fourier transform (IFFT), followed by rainflow cycle counting to simplify the datasets into statistical combinations of different amplitudes and mean stress values. The time-domain dynamic performance indicator τ, calculated through explicit dynamic analysis with a value of 0.136, is used to characterize the system's overshoot and incorporated as a correction coefficient in the damage lifetime calculation formula. The predicted lifetimes based on different models are compared with experimental result and the prediction error of traditional Miner’s rule without overshoot correction is 5.8%. While the overall overshoot correction model tends to overestimate damage, with an error of 6.9%. The partial overshoot correction model, based on the mean value of amplitude differences, outperforms other models in accuracy and generality, reducing the error to 1.4%.

Chip capacitors used in pulsed filed can offer extraordinary discharge energy under elevated electric fields which can be used in high power pulse. However, the low energy density for dielectric ceramic limits the total discharge energy, instead, multilayer-structured design needs to be developed. The ensuing problem is to develop low-temperature sintered ceramics which can be used for the fabrication of multilayered ceramics by cofiring with low-cost Cu electrode. The present study aims to lower sintering temperature and tailors antiferroelectric performances of Cd-doped (Pb, La)(Sn, Zr, Ti)O₃ (PCLSZT) ceramics by phase regulation. The case indicates that the modification of Cd largely reduces the sintering temperature, while Ti regulation can gradually induce an orthorhombic-tetragonal phase transition to optimize dielectric energy storage. The promising energy properties can be obtained (Pb_0.955Cd_0.015La_0.02)(Sn_0.5Zr_0.45Ti_0.05)O₃ under a low field of 260 kV/cm with a charge energy density of 3.52 J/cm³, an energy efficiency of 85%, respectively, accompanied by a rapid discharge speed of t_0.9 = 0.74 μs. This indicates the tunability of energy property in AFE Cd-doped PCLSZT ceramics, thereby providing a potential alternative to develop emerging materials for multilayered pulsed power components.

Trimetallic CoNiMo-hydroxide nanoflakes structure has been effectively prepared on carbon cloth using hydrothermal method. Structural and morphology analysis of the prepared samples has been performed using XRD, FTIR, and FESEM. Galvanostatic charging–discharging (GCD), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) analysis offer valuable insights into the electrochemical properties of the synthesized materials. In this study, varying molar ratios of Co, Ni, and Mo salts are employed to modulate the morphology and electrochemical characteristics of the samples. As the concentration of Mo changes, the morphology transitions from nanorods to nanoflakes, which contributes to an increase in the specific capacitance (C_sp) of the electrode. For CoNiOH, obtained C_sp value is 66.28 F/g at current density of 1A/g which is enhanced to 293.4 F/g at 1 A/g by incorporating Mo in an optimized concentration ratio. The CoNi_(1-x)Mo_xOH electrode exhibits a significant specific capacitance of 307.8 F/g at 0.5 A/g current density. This electrode also showed good cyclic stability (i.e., the capacitance retention of 80% after 1200 cycles). Based on the performance, CoNi_(1-x)Mo_xOH as a hybrid supercapacitive material has high prospective for applications involving energy storage devices.