Journal of Materials Science: Materials in Electronics最新文献

In the present study, ZnO thin films were prepared using RF magnetron sputtering and annealed at temperatures of 150 °C, 300 °C, and 450 °C. The physical properties of the as-grown and annealed ZnO films were studied using XRD, UV–visible, FESEM, and EDS characterization techniques. In addition, the ethanol gas-sensing properties of the films were investigated at room temperature under UV illumination. XRD confirmed enhanced wurtzite crystallinity with (002) orientation for the sample annealed at 300 °C, crystallite size increasing from 6.4 to 13.2 nm, and microstrain decreasing to 0.0089. FESEM showed uniform grains (72 ± 12 nm for the sample annealed at 300 °C); EDS verified the purity of the prepared samples. Band gap narrowed from 3.38 to 3.25 eV upon annealing. Under UV irradiation (365 nm, 2.67 mW cm⁻²), the 300 °C-annealed film exhibited n-type behavior with 18.5% sensitivity, 12 s response, 35 s recovery, and < 5% cycle variation to 1500 ppm ethanol at room temperature. Selectivity to ethanol over acetone and NO₂ was confirmed.

The demand for efficient, lightweight, and radiation-resistant photovoltaic systems for space applications involves the investigation of novel materials beyond conventional silicon. This study presents a thorough examination of spin-tailored magnetic quantum dot-sensitised solar cells (MQDSSCs) utilising doped zinc ferrite (ZnFe₂O₄ quantum dots (QDs) as photosensitisers. Vanadium (V³⁺) and cerium (Ce³⁺) ions were integrated into the ZnFe₂O₄ lattice (V_xZn_1−xFe₂O₄ and Ce_xZn_1−xFe₂O₄; x = 0.0–1.0) by a co-precipitation method to assess their influence on structural, magnetic, optoelectronic, and photovoltaic characteristics. Comprehensive characterizations such as X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), UV–Vis, Photoluminescence (PL), X-ray Photoelectron Spectroscopy (XPS), and Vibrating Sample Magnetometer (VSM) reveal that doping significantly modulates crystallite size (18–45 nm), lattice strain, cation distribution, bandgap, and magnetic ordering (M_s = 0.2–7.04 emu g⁻¹). Photovoltaic studies indicate improved device performance following doping, with Ce-doped ZnFe₂O₄ (x = 0.4) attaining a peak power-conversion efficiency (PCE) of 10.2% (V_oc = 0.703 V, J_sc = 20.5 mA cm⁻², Fill Factor = 70%), representing a 2.3-fold enhancement compared to the highest-performing V-doped sample (6.5% at x = 0.2). The enhanced performance of Ce-doped QDs is ascribed to bandgap narrowing generated by 4f orbitals, less charge recombination, and increased radiation tolerance. These results identify Ce_0.4Zn_0.6Fe₂O₄ as a viable choice for space-grade photovoltaic applications, presenting a distinctive amalgamation of elevated efficiency, magnetic-field flexibility, and durability in severe extraterrestrial environments.

Ferrite materials properties can be precisely tailored by adjusting their spinel structure to optimize cation distribution and electronic configuration. Furthermore, doping with various elements significantly enhances their functional qualities. An auto − combustion technique was used to dope nickel ferrite with different Mn²⁺ concentrations, producing the Ni_1−xMn_xFe₂O₄ (x = 0.1, 0.3, and 0.5) nanoparticle series. The crystallite size is compared with Debye–Scherrer, modified Debye–Scherrer, and the W − H plot, and the observations are recorded. The electrochemical investigations revealed a reversible and stable redox behaviour, with distinct potential plateaus indicating oxidation and reduction peaks, and a strong linear correlation (R² = 0.979). Notably, the specific capacitance analysis uncovered an inverse relationship between current density and charge storage capacity, with a maximum specific capacitance of 215 F g⁻¹ at 0.5 A g⁻¹ for NMF-0.5. This sample also showed power and energy density of 125 Wh kg⁻¹ and 14.9 W kg⁻¹, respectively. The electrical properties, such as AC conductivity, was studied using Joncher's power law fitting, with a conductivity of up to 3.37 × 10⁻⁵ S cm⁻¹ and a DC conductivity of 2.0 × 10⁻⁵ S cm⁻¹, highlighting the potential applications of the obtained materials in both low- and high-frequency ranges. The superior performance of this sample is attributed to the synergistic-effects of multivalent states, an exceptional porous structure, and minimal charge transfer resistance.

Uniform nanorod-like Eu²⁺, Tb³⁺, Cr³⁺ co-doped non-stoichiometric Mg–Al spinel was synthesized via hydrothermal treatment (140 °C × 24 h) followed by mild calcination at 1100 °C. The effects of stoichiometric ratio ((n_{{Mg^{2 + } }} :n_{{Al^{3 + } }}) = 1:x) on Tb³⁺ single-doped non-stoichiometric spinel were investigated, along with the energy transfer and multicolor luminescence regulation in Eu²⁺, Tb³⁺, Cr³⁺ co-doped samples. Results show that: As the Al stoichiometry increased from x = 2.0 to 3.2, the Tb³⁺ single-doped samples transformed from a mixture of aluminum-rich spinel and MgO phases into single-phase aluminum-rich spinel. At x = 4.0, the defect-rich aluminum-rich spinel structure exhibited the most significant enhancement effect on Tb³⁺ emission. Building upon the optimal Tb³⁺ single-doped system, the introduction of f-d transition ions (Eu²⁺ and Cr³⁺) formed effective co-doping without altering the host structure. Under 339 nm excitation, the Eu²⁺  → Tb³⁺ energy transfer efficiency reached 65.09%, enabling color-tunable emission from bluish green → pale blue → pure blue in Eu²⁺, Tb³⁺ co-doped samples. By varying excitation wavelengths between 330 and 377 nm, the Eu²⁺, Tb³⁺, Cr³⁺ tri-doped system achieved multicolor modulation from pure blue → pale blue → ultimately near-white light. This phosphor is therefore a promising candidate for multicolor display applications, especially for white-light emission.

Environment friendly CuInS₂ (CIS) quantum dots (QDs) are synthesized by the hydrothermal method using 3-mercaptopropionic acid (MPA) as a stabilizer. XRD studies of CIS QDs show chalcopyrite tetragonal structure, which is further confirmed by Raman spectroscopy. HRTEM analysis shows average particle size around 6.1 nm and inter planar spacing of 0.31 nm corresponding to (1 1 2) lattice plane of CIS QDs. XPS analysis provides insight into surface elemental analysis and oxidation states of CIS QDs. Optical properties are enhanced by varying parameters such as Cu: MPA concentration, Cu:In ratio, reaction time, pH, and reaction temperature. The bandgap determined from Tauc’s plot varied from 1.18 to 2.55 eV, confirming the strong quantum confinement effect. Chromaticity coordinates for CIS QDs were calculated using CIE-1931, and the coordinate shows orange-red color emission of CIS QDs. Variation of Urbach energy and fluorescence quantum yield (FQY) of the material as a function of various reaction parameters is studied to obtain defect-free highly fluorescent QDs. The study revealed a strong correlation between Urbach energy and FQY. Maximum FQY of 19.68% is achieved for CIS QDs of molar ratio 1:8. Excitation wavelength independent and intensity-dependent emission behavior demonstrates stable and tunable radiative recombination. The material also showed excellent photostability under prolonged irradiation of visible light. These findings establish MPA-capped CIS QDs as promising, eco-friendly wavelength converters for potential application in next-generation light-emitting diodes (LEDs) and other optoelectronic devices.

In this work, CeO₂/Fe₂O₃ nanocomposites were prepared via a microwave-assisted synthesis route followed by annealing, aiming to overcome existing limitations and enhance supercapacitor performance. Comprehensive characterization using XRD, FTIR, FESEM-EDS, and BET analyses confirmed significant improvements in structural and textural features, such as enlarged surface area, higher porosity, and abundant redox-active sites. Electrochemical testing revealed a remarkable specific capacitance of 980 F g⁻¹ at 1 A g⁻¹, notably surpassing that of pristine CeO₂. When assembled into an asymmetric device (CeO₂/Fe₂O₃//AC), the system delivered an energy density of 24.2 Wh kg⁻¹ and a power density of 500 W kg⁻¹, while maintaining 92.3% of its initial capacitance after 8000 charge–discharge cycles and achieving nearly 97% coulombic efficiency. The enhanced performance is attributed to the synergistic coupling of CeO₂ and Fe₂O₃, which boosts redox activity, facilitates rapid charge transfer, and improves ion diffusion. These findings highlight the promise of microwave-assisted CeO₂/Fe₂O₃ nanocomposites as candidates for next-generation high-performance supercapacitors.

Graphene-decorated spinel composites are emerging as a novel material with potential applications in flexible electronic devices and contemporary energy storage systems due to their robust mechanical properties, flexibility, cost-effectiveness, and lightweight nature. In the present study, the composite of Cu_0.3Co_0.7Ho_0.1Fe_1.9O₄ with 7.5% graphene has been synthesized through the sol–gel auto-combustion process. The X-ray diffraction analysis proves the formation of a single-phase face-centered cubic spinel structure. The lattice parameter is found to be 8.364 Å at the temperature of 600 °C and 8.330 Å at 900 °C. In the same way, the crystallite size decreases from 10.476 nm at 600 °C to 7.749 nm at 900 °C. The scanning electron microscope images indicate a uniform distribution of the grains with no significant alteration in the grain size with an increase in sintering temperature. Raman Spectra detect five different vibrational modes, where the A_1g and E_g modes are related to tetrahedral Fe–O stretching and O²⁻ bending vibration, and the T_2g modes are the vibrations of the octahedral sites. Vibrational bands found at 620–710 cm⁻¹ and 410–620 cm⁻¹ identify the A-site and B-site metal ions, respectively. Moreover, the ferrite composite that has been sintered at 800 °C has minimal dielectric losses and a minimal activation energy of 0.46 eV. Higher temperatures increase AC conductivity, particularly at high frequencies. Furthermore, the electrical conductivity of the studied composite changed between 2.69 × 10^–11 and 0.012 × 10^–11 Ω⁻¹ cm⁻¹. These characteristics underscore the potential of the studied composite for next-generation electronic devices.

In this study, bimetallic Co-doped SnSe nanoparticles are synthesized through the precipitation method. The nanoparticles were synthesized in five different ratios (i.e. 1%Co-doped SnSe named CSS1, 3%Co-doped SnSe named CSS2, 5%Co-doped SnSe named CSS3, 7%Co-doped SnSe named CSS4, and 9%Co-doped SnSe named CSS5). The CSS1, CSS2, CSS3, CSS4, and CSS5 nanoparticles were examined using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infra-red spectroscopy (FTIR), and transmission electron microscopy (TEM) studies. The XPS confirms the binding energy of the Co, Sn, and Se elements in the CSS3 nanoparticles. The TEM shows the images of interconnected rod-like and flower-like morphology. The CSS1, CSS2, CSS3, and CSS4 electrodes were used to study electrochemical performance in 1 M KOH. The CSS4 electrode attains a capacitive retention of 78% and a coulombic efficiency of 96% even after 1000 GCD cycles. Further, the CV curves obtained before and after the cyclic test shows an enhancement after 1000 GCD cycles, indicating its stability for use in supercapacitor electrodes.

Recently, Ni²⁺ doped inorganic luminescent materials have received extensive attention owing to their ability to achieve broadband near infrared II region (NIR-II) emission. However, reported materials still suffer from the disadvantages such as poor luminous thermal stability. Herein, a range of broadband NIR-II phosphors Mg₂LaTaO₆: Ni²⁺ (MLT: Ni²⁺) were synthesized successfully. The titled phosphors emit NIR-II light (1000–1700 nm) under 407 nm excitation, the full width at half maximum is as wide as 207 nm. Compared with existing NIR-II phosphors, MLT: Ni²⁺ phosphors present satisfactory thermal stability of luminescence (the integral intensity at 423 K is 81.07% of that at 273 K). Due to the weak crystal field and high structure stiffness, the materials exhibit high photoluminescence quantum efficiency (the optimal value is 45.3%). A pc-LED prepared by combining MLT: Ni²⁺ phosphor with near ultraviolet LED chip with a drive current of 100 mA and an output power of 2.36 mW. This work presents important reference significance for the exploring of Ni²⁺ doped NIR-II emitting phosphors with excellent luminous thermal stability.