Journal of Materials Science: Materials in Electronics最新文献

Praseodymium oxide (Pr₆O₁₁) was embedded in the polyvinyl alcohol (PVA) matrix with different contents for the first time, using the casting method for preparation. Combining rare earth oxides with a polymer matrix has gained a lot of interest in optical applications lately. The impact of Pr₆O₁₁ on the PVA’s morphology and bandgap energy was our interest in the present study. PVA’s structure and morphology were determined via X-ray diffraction (XRD), Raman, Fourier transform infrared (FTIR), and scanning electron microscope (SEM) techniques. The XRD showed the influence of Pr₆O₁₁ on the characteristic peak of the PVA, indicating the change in the PVA’s structure and producing a new one. FTIR and Raman analyses demonstrated the combination and interaction between the Pr₆O₁₁ nanoparticles and the functional groups of the PVA. The optical constants were investigated through the absorbance data recorded from the UV–Visible spectrophotometer. The PVA’s bandgap energy (direct/indirect) was reduced to 4.51/2.13 eV, and the refractive index increased to 2.0902 after adding 4 wt.% Pr₆O₁₁ nanoparticles. Other optical parameters were determined and showed an improvement with the additive of Pr₆O₁₁ to the PVA matrix. The obtained matrix showed promising characteristics for optical materials applications.

Economical nano-scale CaCO₃ particles with superior aqueous dispersion and facile preparation process of sand milling are demonstrated. The spin-coated CaCO₃, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and CaCO₃-doped PEDOT:PSS films are characterized with scanning electron microscope, atomic force microscope, X-ray/ultraviolet photoelectron spectroscopy, current–voltage characteristics and impedance spectroscopy analysis, confirming good surface morphology and satisfactory hole injection properties. With CaCO₃-doped PEDOT:PSS tailoring hole injection and 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole as emitter, efficient near ultraviolet organic light-emitting diodes have been constructed. The device gives maximum external quantum efficiency of 1.16%, radiance of 1.95 mW/cm², and stable electroluminescent spectra peaking at 395–404 nm.

Soft magnetic materials play a crucial role in various devices, making them indispensable in modern electrical engineering and electronics. In this work, Mn_0.1Fe_0.1Gd_x thin films were synthesized through an electrodeposition method, with the Gd concentration systematically varied to study its effect on the films properties. As the Gd content increased, the magnetic properties of the films were enhanced, particularly in terms of their low coercivity, making them highly suitable for soft magnetic applications. Surface morphology analysis showed cauliflower-like agglomerates, which grew larger as the Gd content increased. The optical properties were also influenced by the Gd content, as demonstrated by strong absorption in the visible region, making these films potentially useful for applications requiring both magnetic and optical functionalities. The XRD patterns confirmed the crystalline structure of the films, while EDX analysis validated the elemental composition and uniform distribution of Gd within the films.

Potassium sodium niobate-based ferroelectric materials are potential alternatives to Pb-based perovskites due to their outstanding ferroelectric and piezoelectric properties. In our previous work, (Na_0.5K_0.5)_1-xAg_xNb_1-xTa_xO₃ was constructed with a coexistence of orthorhombic and tetragonal phases at room temperature, successfully regulating various polarization properties. However, despite the x = 0.075 sample's excellent piezoelectric and ferroelectric characteristics, the significant coercive field it exhibits poses a challenge for polarization. Further investigation is needed to address this issue. This study introduces SrTiO₃ as a second phase into (Na_0.5K_0.5)_0.925Ag_0.075Nb_0.925Ta_0.075O₃, effectively regulating the microstructure and disorder. Moreover, leveraging the synergistic effect of phase boundary and disorder engineering, the ferroelectric properties are well modulated at room temperature. These results provide valuable methods and guidance for regulating ferroelectric properties in lead-free ferroelectrics.

Bismuth iron oxide is a promising material that can exhibit ferroelectric and ferromagnetic phenomena simultaneously at room temperature. However, some problems related to bismuth iron oxide include volatile nature of bismuth oxide and large value of leakage current. Present study is an attempt to address these problems by doping manganese (Mn) in BiFeO₃ with varying Mn concentration from 1 to 5wt%. The sols of undoped and doped BiFeO₃ are processed by microwave-assisted sol–gel method at a power of 720 W. These sols are spin deposited on copper substrates and annealing was performed at temperature of 350 °C. XRD analysis shows the incorporation of doping ions without altering the rhombohedral structure. Crystallite size is found to be less than cycloidal spin structure. Ferromagnetic nature with high value of saturation magnetization was observed in doped samples. The microwave synthesized thin films show normal and anomalous behavior, i.e. U-shaped dielectric response. The dominant role of grain boundaries is observed from Cole–Cole plots. ME coupling is observed for the samples that makes this material an interesting system to be considered in magneto electric applications.

Nanocomposites offer a wide range of applications and have the potential to revolutionize various industries. Through carefully selection of the matrix material and nanoparticles, it becomes possible to fabricate materials that possess customized properties, hence, tailoring to specific needs and efficiently addressing challenges encountered in various applications. Zinc oxide (ZnO), strontium ferrite (SrFe₁₂O₁₉), and their nanocomposites ZnO/xSFO (x = 1%, 3%, and 5%) have been synthesized using the co-precipitation method. X-ray diffraction assures the crystal structure of ZnO, SFO, and their nanocomposites, with crystallite size of 27 nm for ZnO and 41 nm for nanocomposites. High-resolution transmission electron analysis shows the semi-spherical agglomerated polycrystalline particles with particle size 25 nm, 9 nm, and 47 nm for ZnO, SFO, and ZnO/5%SFO, respectively. The dielectric characteristics and ac conductivity were examined as a function of frequency (4–8 MHz) and at different temperatures ranging from 30 to 180 °C. The results obtained at room temperature show the dielectric constant, dielectric loss factor, and ac conductivity are enhanced by increasing SFO content, reaching their peak at a concentration of 3% SFO. The mass attenuation coefficient of incident neutrons in the energy range from 10^–5 eV to 20 MeV was studied to evaluate the ability of the prepared samples as neutron-shielding materials. SFO sample has higher neutron attenuation capability than other investigated samples. The study indicates that the total mass attenuation coefficient in the 1 eV to 1 MeV neutron energy range primarily results from elastic interactions for all materials under investigation. The results indicate that higher SFO concentrations in ZnO result in a slight increase in absorption at low energies and in elastic scattering at higher energies. Furthermore, the results indicated that the attenuation coefficient of the samples for fast neutrons in the range of 2 MeV to 12 MeV is (approx) 0.14 cm⁻¹, a notably high value compared to many shielding materials reported in various literature.

Exploring prospective materials to develop efficient and durable supercapacitor electrode becomes a key challenge for researchers. For this, halide perovskite gained considerable attention in diverse fields because of their flexible chemistry and outstanding ionic conductivity. However, their use for energy storage found limited. In this perspective, halide perovskite (LiZrBr₃)-based composites with rGO were synthesized by solid-state reaction method, aimed to fabricate advanced supercapacitor electrodes with enhanced supercapacitive performance. The physico-chemical properties were thoroughly characterized using techniques including XRD, FE-SEM, EDX, CV, GCD, and EIS. XRD confirmed the phase purity. FE-SEM coupled with EDX confirmed the incorporation of rGO in halide perovskite with porous type morphology along with the presence of the constituent elements Li, Zr, Br, and C. BET confirmed the mesoporous structure. From electrochemical analysis, CV showed pseudocapacitive character of the electrode. The high specific capacitance (1328.5 F/g), power density 340.4 W/Kg), and energy density (59.1 Wh/Kg) in case of composite were achieved with an exemplary cyclic performance of 91.2% over 3000th charging-discharging cycles, as compared to pure at current density of 0.5 A/g. EIS analysis further supported these findings, as the Nyquist plot showed a small semicircle, indicating low charge transfer resistance for the LiZrBr₃/rGO composite. The observed results proposed that halide perovskite composites (LiZrBr₃/rGO) hold great promise for advancing next-generation energy storage devices as supercapacitor electrodes.

In this work, the characterization and testing of sensing properties of ZnTe powders for detecting carbon monoxide were investigated. The ZnTe synthesis was reached by a solvothermal process, using three different green solvents, methanol, ethanol, and isopropanol. The structural, morphological, and compositional properties of ZnTe powders were analyzed by X-ray diffraction, XRD, scanning electron microscopy, SEM, and atomic force microscopy, AFM, and X-ray energy dispersion (EDS), respectively. XRD confirmed the zincblende-type cubic phase of ZnTe, with crystallite sizes of the order of 69 nm. SEM images of all synthesized samples showed a surface covered with particles of different sizes and irregular morphologies. Finally, the sensing response of ZnTe samples to CO was measured for concentrations varying from 1 to 500 ppm at different operating temperatures, 100, 200, and 300 °C. The highest sensitivity, 18.4, was obtained for ZnTe samples synthesized from isopropanol as solvent, so ZnTe powders showed a good response for CO detection, resulting these materials promising to be applied as gas sensors.

The present work analyses the effect of transition metal decoration on field emission properties of vertically aligned carbon nanotubes (VACNTs). Several transition metals (Co, Ni, Cu, and Zn) have been decorated on VACNTs to examine the role of d-state occupancy on the field emission properties. It is found that d-state occupancy does play a role in governing the current density, and it is not always possible to explain the field emission results only on the basis of conventional parameters like field enhancement factor and work function. The present study shows that among the studied transition metals and their oxides, Zn and CuO-decorated VACNTs give the most promising field emission results.

The interaction between TiO₂ and V₂O₅ can not only improve the physico-chemical properties of the material but also the dielectric and conductive properties of the material. For this purpose, TiO₂ samples with 5, 7, and 10 wt% V₂O₅ were prepared by the impregnation method to investigate the dielectric properties and AC conductivity. The phase composition and morphology of the V₂O₅/TiO₂ samples were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM)-scanning transmission electron microscope (STEM). Regardless of the vanadium content, the samples exhibit non-spherical structures and particles with size in the range of 60–200 nm. The small V₂O₅ peaks in XRD were detected at 7.0 and 10 wt% V₂O₅. In addition, the specific surface area for 5 and 7 wt% V₂O₅ was determined to be 9.2 m²/g, but at 10 wt% V₂O₅ the surface area of the sample decreases to 7.5 m²/g as the titanium dioxide pores are filled by vanadium. The DR–UV–Vis spectra of V₂O₅/TiO₂ samples showed that the sample with 5 wt% V₂O₅ has isolated tetrahedrally coordinated V⁵⁺ species and increasing the V₂O₅ loading leads to the formation of octohedrally coordinated V⁵⁺ species in V₂O₅ clusters. Comparison of the Raman spectra of V₂O₅/TiO₂ and TiO₂ samples showed the formation of α-V₂O₅ on the TiO₂. In addition, a detailed analysis of the Nyquist diagrams shows how sensitively the electrical properties of the materials react to changes in temperature and frequency. Jonscher’s power law is used to analyze alternating current and conductivity, and it is found that the fluctuation of the exponent “s” adequately describes the conduction mechanism and agrees with CBH models. As the TiO₂ concentration increases, the value of the activation energy generated decreases. The higher presence of Ti⁴⁺ ions due to the increase in molar volume is the cause of this increase in charge carrier mobility. The effect of the grain and grain boundary on the overall impedance is revealed by a dielectric study, which also confirms that the combination of titanium dioxide and vanadium oxide nanoparticles improves the dielectric and AC conductivity of the samples.