Ac Conductivity Research Articles

An investigation for optical, photocatalytic, photoluminescence and dielectric properties of Cd0.40Ni0.60ZnO2 annealed nanocomposites

We report here the optical, photoluminescence (PL), and dielectric properties of Cd0.40Ni0.60ZnO2 nanocomposites annealed between 200 and 600oC. An increase in annealing temperature (Tann) up to 600oC correlates with a gradual increase in the crystallite and particle sizes. The surface area, pore radius, and pore volume are increased as Tann increases from 200oC to 300oC, and then decreased, but still higher than of 200oC. Similar behaviors were obtained for the absorbance carrier density, photocatlytic efficiency, degradation rate, PL intensity, dielectric constant, dielectric loss, ac conductivity, F-factor, series resistance, and electronic polarizability. While the energy gap, binding energy, impedance of grains and their boundaries, and effective capacitance show an opposite behavior. The relaxation times at the peak of dielectric parameters are between 11.54 and 159.24ns and between 35.23 and 24273.73ns, respectively. The Cole-Cole plot shows a single semicircle at Tann < 400oC and two successive semicircles at Tann> 500oC. The energy of PL of visible emissions is independent on the chosen Tann. These findings indicated that the nanocomposite annealed at 300oC can be used for water purification, telecommunications, solar cells, supercapacitor, and white light-emitting diodes (LEDs).

The study of the dependence of dielectric properties, electric modulus, and ac conductivity on the frequency and voltage in the Au/(CdTe:PVA)/n-Si (MPS) structures

The dielectric properties, electric modulus, loss tangent (tanδ), and ac conductivity of the fabricated Au/(CdTe:PVA)/n-Si (MPS) structures were investigated in wide-range frequency. By using the capacitance/conductance–voltage–frequency (C/G-V-f) measurements, the real/imaginary components of complex dielectric constant (εʹ, εʺ)/electrical modulus (M′\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$M{\\prime}$$\\end{document}, M′′\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$M{\\prime}{\\prime}$$\\end{document}), loss tangent (tanδ), and σac were calculated in wide-range frequency (2 kHz–0.7 MHZ) and voltage (± 2.5 V), and all results show that these parameters are a strong function of voltage and frequency. The observed decreases of εʹ and εʺ with increasing frequency were attributed to the existence of Nss, interlayer, and dipole polarizations. The value of εʹ was calculated as 128.38 (at 2 kHz and 2.5 V), which is quite higher than the maximum value of traditional SiO2. ln(σac)–ln(f) plot for 0.7 V shows three linear parts, indicating three different conduction mechanisms at low, intermediate, and high frequencies. These results show that the fabricated MPS structures can be successfully used instead of traditional metal–insulator–semiconductor as ultra-capacitors, which can use more electronic charges or energy.

Structural, magnetic, low and high frequency dielectric properties of Al-substituted M-type SrCe hexaferrites synthesized in the presence of tecomastans (yellow bell) leaves extract

This paper represents a study of the effect of Al-substitutions on structural, magnetic, and dielectric properties of Sr0·8Ce0·2Fe12-xAlxO19 (x = 0.00, 0.25, 0.50, 0.75 and 1.00) ferrites synthesized in presence of yellow bell leaves extract. All samples were synthesized using the sol-gel combustion technique with the influence of green synthesis by using leaves of Tecomastans (yellow bell) plant. These samples were preheated at 550 °C for 4 h and finally calcinated at 1150 °C for 6h. These samples were characterized using XRD, FTIR spectroscopy, SEM, VSM, LCR measurements, and VNA measurements. XRD analysis confirm the formation of a magnetoplumbite M-phase (hexagonal) with a minor impurity phase of CeO2 in all samples. Lattice parameters a and c are obtained from rietveld refinement, which are found in the range from 5.859 Å to 5.883 Å, and 22.96 Å to 23.05 Å respectively. FTIR spectra confirm the absence of organic compounds and the presence of an absorption band in the fingerprint region, which are linked to the stretching of the metal-oxygen bond at the octahedral and tetrahedral sites. The surface morphology of these samples is analyzed using SEM images. Grains with hexagonal plate shapes were observed in each sample. The average grain size varies in the range of 0.565 μm–1.455 μm. EDS data confirms the presence of desired elements in the respective sample. VSM analysis shows hard magnetic behavior in all samples. Magnetic parameters were found in the range, Ms: 36.281–43.397 emu/g, Mr: 12.297–19.841 emu/g, Hc: 2.0987–3.814 kOe. In low-frequency (20 Hz-2 MHz) dielectric measurements, the dielectric constant is high at low frequencies, which rapidly falls as frequency increases. Loss tangent curve shows a relaxation peak for each sample above 200 kHz. AC conductivity is very low in the order of 10−5 S/m in plateau region below 2 kHz, which increases as frequency increases. Cole-Cole plot suggests the effect of grain boundary contribution is higher in non-substituted sample compared to Al-substituted samples. In high-frequency (0.2 GHz–20 GHz) measurements, the dielectric constant remains almost constant. These values are found in the range 5–7.5. Low loss tangent of 0–0.16 were observed in every sample in this frequency domain, with AC conductivity of the order of 10−2 S/m.

Optical, Structural, and Dielectric Characteristics of Flexible PVA/PEG/ZnMn2O4/CuCo2O4/x wt % Melanin Blended Polymer Composites

Our research described in the current paper was aimed to alter the optical and dielectric characteristics of polyvinyl alcohol/polyethylene glycol blended polymers by incorporating different quantities of melanin and ZnMn2O4/CuCo2O4 to create flexible blended polymer composites suitable for applications like photocatalysis, capacitors, and different optoelectronic applications. The PVA/PEG/ZnMn2O4/CuCo2O4-x wt % melanin blended polymer composites were created using a casting technique. The structural properties of the fillers and various blends were investigated using an X-ray diffraction technique. A transmittance electron microscope was used to investigate the features of the ZnMn2O4/CuCo2O4. The optical properties of the PVA/PEG/ZnMn2O4/CuCo2O4-x wt % melanin blend composites, which included their linear and nonlinear optical parameters, were analyzed using a diffused reflectance technique. The direct and indirect optical energy gaps attained their lowest values (5.47, 3.22, and 2.97) and (5, 1.18) eV in PVA/PEG/ZnMn2O4/CuCo2O4 blended polymer. The doped blends exhibited superior absorbance efficiency in the UV spectra in both the UVA and UVB regions. In the UV and visible ranges doped blends with 15 and 10 wt % of melanin had the highest refractive index values, respectively. The highest dielectric constant and electric ac conductivity were achieved as the blend was loaded with 5 wt % melanin. The energy density value of the doped blend containing 10% melanin was the highest when compared to other doped melanin polymers. The maximum height electrical potential barrier of each blend was also calculated. The electric modulus was also studied. The intensities of the emission peaks in terms of fluorescence characteristics were reduced as the PVA/PEG blend was loaded with ZnMn2O4/CuCo2O4-x wt % melanin. In conclusion, the PVA/PEG/ZnMn2O4/CuCo2O4-x wt % melanin blended polymer composites are promising hybrid materials for use in a variety of applications.

The enhancement of electrical properties of TiO2/xCoFe2O4 nanocomposites for extended applications

The pure TiO2 and TiO2/xCoFe2O4 nanocomposites (0, 2, 4, and 6 wt. %) were synthesized using the sonomechanical method at room temperature. The prepared specimens were studied by scanning electron microscopy (SEM), energy-dispersive X-ray techniques (EDX), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and ac conductivity measurements. The sample exhibited homogeneous and well-distributed spherical nanoparticles of visible surface edges with average grain size ranging from 100 to 200 nm, as shown in the SEM micrograph. Raman spectra analysis showed the characteristic band for TiO2 at 141.2, 233.08, 447.13, 609.55, and 639.4 cm−1. The FTIR confirmed the interaction of CoFe2O4 and TiO2 reflecting the successful formation of nanocomposites. Compared to pristine TiO2, both the dielectric constant (ε') and conductivity were boosted by the inclusion of CoFe2O4. The behavior of the exponent factor (S) with temperature demonstrates that the conduction mechanism is the correlated barrier hopping (CBH) mechanism. The investigation of complex electric modulus established that the vertiginous nanocomposite had a non-Debye-type relaxation. The observed properties prove that TiO2/ xCoFe2O4 (x = 0, 2, 4, and 6 wt. %) nanocomposites are very functional for electric storage applications.

Tunability of impedance spectroscopy, electrical conductivity and optical properties of Cu-doped TiO2 nanostructures for optoelectronic device application

This paper details the successful fabrication of Cu-doped TiO2 nanostructures using a co-precipitation method. A thorough analysis of the structural and electrical characteristics of the nanostructure samples was carried out. It was found that all synthesized samples exhibited an anatase TiO2 structure. The XRD pattern indicated an average crystalline size of 23.19 nm for Cu-doped TiO2 nanostructures, whereas TiO2 nanostructures showed a size of 11.78 nm. The UV-Visible spectrum indicated a noticeable absorption band shift towards longer wavelengths, coupled with an increased absorption rate of light. Analysis of electrical conductivity showcased temperature-dependent variations in conductivity at high frequencies. Impedance spectroscopy unveiled improved conductivity upon the integration of Cu into TiO2 nanostructures. Nonetheless, at 300 K, copper doping resulted in a decline in electrical conductivity, whereas at elevated temperatures, Cu doping showed a increase in conductivity for the nanostructures samples. These findings underscore the potential and applicability of the nanostructures, showcasing improved AC conductivity and electrical characteristics, making them promising for various electrical applications.

Tuning the band gap, optical, mechanical, and electrical features of a bio-blend by Cr2O3/V2O5 nanofillers for optoelectronics and energy applications

This work presents a facile approach for controlling the optical and electrical parameters of a biopolymeric matrix for optoelectronics. Vanadium oxide (V2O5) and chromium oxide (Cr2O3) nanoparticles (NPs) were prepared and incorporated into the carboxymethylcellulose/polyethylene glycol (CMC/PEG) blend by simple chemical techniques. Transmission electron microscopy (HR-TEM), and X-ray diffraction (XRD) data showed that V2O5 and Cr2O3 exhibited spherical shapes with sizes in the range of 40–50 nm and 10–20 nm, respectively. In addition, the blend's degree of crystallinity was sensitive to the V2O5 and Cr2O3 doping ratios. The scanning electron microscopy (FE-SEM) and the elemental chemical analysis (EDAX) used to study the filler distribution inside the blend, and confirmed the existence of both V and Cr in the matrix. Fourier transform infrared (FTIR) spectroscopy showed that the dopants significantly affected the blend reactive (C–O–C, OH, and C=O) groups. The stress–strain curves illustrated the reinforcing effect of the dopants up to 1.0 wt\\%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ ext{wt\\%}$$\\end{document} Cr2O3/V. The transmittance and absorption index spectra in the visible-IR wavelengths decreased with increasing filler content. Utilizing Tauc's relation and (optical) dielectric loss, the direct (indirect) band gap narrowed from 5.6 (4.5) eV to 4.7 (3.05) eV at 1.0 wt\\%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ ext{wt\\%}$$\\end{document} Cr2O3/V. All films have an index of refraction in the range of 1.93–2.17. AC conductivity was improved with increasing filler content and temperature. The energy density at 50 °C is in the range of 1–3 J/m3. The influence of V2O5 and Cr2O3 content on the optical conductivity, dielectric constant, loss, and dielectric modulus of CMC/PEG was reported. These enhancements in electrical and optical properties, along with the potential for band gap engineering, offer promising prospects for advanced applications in optoelectronics and energy-related fields.

A Comprehensive Study of Cerium-Modified Bi2FeMnO6 Double Perovskite: Synthesis, Structure, Properties and Applications

This paper presents a detailed synthesis method by solid-state reaction route and typical characterization (structural, microstructural, dielectric, impedance, modulus, and optical properties) of a double perovskite material Bi2FeMn[Formula: see text]Ce[Formula: see text]O6. An orthorhombic crystal structure having an average crystallite size of 32.2[Formula: see text]nm is suggested by X-ray diffraction data (XRD). Scanning electron microscope (SEM) micrograph detects the presence of cylindrical nanorod-shaped distinct grains and well-defined grain boundaries in this material and the average grain size is 5.82[Formula: see text][Formula: see text]m. Furthermore, the purity and the presence of all constituent elements in the material were confirmed from energy dispersive X-ray (EDX) analysis and color mapping. Dielectric, impedance, modulus, and AC conductivity properties are studied within the temperature range of 25–500∘C and frequency range of 1[Formula: see text]kHz to 1[Formula: see text]MHz. The high dielectric constant at a low-frequency zone and low dielectric loss found in this material make it a promising candidate for better energy-storing devices. The negative temperature coefficient of resistance (NTCR) behavior is observed from the impedance study. The non-Debye relaxation is detected in the modulus study. The semiconducting nature of this material is verified by semicircular arcs observed in both Nyquist and Cole–Cole plots. The thermally activated conduction mechanism is confirmed by an AC conductivity study. The existence of Bi–O, Fe–O, Mn–O and Ce–O stretching vibrations are observed from the FTIR study and explain the presence of all constituent elements in the sample. The bandgap energy of 1.7[Formula: see text]eV is calculated from UV-DRS analysis and hence this material can be used for advanced optoelectronic and photovoltaic applications.

Structural, optical, and dielectric properties of aminated PMMA/GO polymer nanocomposite for storage device applications

A series of aminated PMMA/GO polymer nanocomposite (PNG) were synthesized by solution mixing in two step process. The synthesized PNG samples were analysed using X-ray diffraction (XRD), Fourier transform infrared (FTIR), Scanning Electron Microscope (SEM), energy dispersive X-ray analysis (EDAX), Thermo-gravimetric, differential thermal analysis (TG-DTA), UV–Visible spectroscopy (UV–Vis) and impedance spectroscopy. The X-ray diffraction (XRD) data indicated the existence of crystalline nature in PMMA and the reduction of graphene oxide (GO) which is also confirmed by TGA and DTA results. The interaction between graphene oxide nanoparticles and the functionalized polymer matrix has been validated using FTIR investigations. The SEM and EDAX measurements demonstrated the homogeneous dispersion of graphene oxide (GO) over the surface of the produced samples. The UV–Vis spectroscopy analysis revealed that the optical energy gap values of nano composites decrease as the amount of graphene oxide nanoparticles increases. All samples exhibited higher relative permittivity at low frequencies which is a key factor for high energy density. As the concentration of GO increases, the maximum peak of dielectric loss tangent also shifted to higher frequency due to increase in interfaces. The β relaxation is dominant in non-polar PMMA due to the functionalisation and dispersion of GO. The AC conductivity values increased with increase in concentration of GO. The single semicircle in plot from impedance spectroscopy and the drop in bulk resistance values of PNG samples made them as a good material for energy storage devices like supercapacitors.

The Role of Adsorption Phenomena in ac Conductivity Measurements of Dielectric Nanoparticle Suspensions

The authors of numerous measurements of conductivity for suspensions of nanoparticles of various types carried out in the last decade came to the general conclusion that the well-known Maxwell’s theory is not applicable to quantitative explanation of the properties of such systems. In the present work, we demonstrate that the Maxwell’s theory can be still applicable even for such systems, but the specifics of the standard ac measurements have to be correctly taken into account. Namely, the dependence of the capacitance of “metal–electrolyte” cuvette boundaries on nanoparticle adsorption, which in its turn dramatically depends on nanoparticle concentration, has to be taken into account. The latter circumstance strongly (via the RC characteristic of the circuit) affects the results of conductivity measurements. We propose the new algorithm of the impedance measurement data analysis for the particles’ concentration dependence of conductivity σ(ϕ) (where ϕ is the volume fraction of nanoparticles in suspension) for the suspensions of the diamante nanoparticles in alcohol which demonstrates the adequate correspondence of the Maxwell’s theory to the available experimental findings.

Influence of the Mn/Fe ratio on structural, optical, electrical and magnetic characteristics of MnFeMgNiO spinel ferrites

MnxFe2-xMg0.5Ni0.5O4spinel ferrite nanoparticles (0.0 ≤ x ≤ 1) were prepared utilizing a flash auto-combustion technique. The as-prepared ferrite nanoparticles have been investigated and characterized using X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), and Fourier transform infrared analysis (FTIR). The dielectric, optical and magnetic characteristics of the synthesized spinel ferrite samples were investigated using broadband dielectric spectroscopy (BDS), diffuse reflectance spectroscopy (DRS) and vibration sample magnetometers (VSM). The cubic phase spinel ferrite with space group Fd-3m was identified through XRD. X-ray diffraction indicates that the lattice constant increases and the crystallite size declines with increasing Mn concentration. The positions of the cations and their vibrational modes in the crystal structure with oxygen ions are demonstrated through the FTIR spectra. The morphology was examined using HRTEM showed polycrystalline cubic spinel structure with faceted planes. The optical band gap Eg was determined using Kubelka–Munk model where, it decreased from 1.79 eV to1.24 eV as Mn content increases. The replacement of manganese significantly affects the dielectric characteristics of the synthesized spinel ferrites. The real (ε′), imaginary (ε″) parts of dielectric constant and ac conductivity exhibit an increase in their values as manganese substitution (x) increases from 0 to 0.25 mol %, and thereafter decreases. The presence of a relaxation phenomenon in all prepared samples except the undoped sample (Ni0.5Mg0.5Fe2O4) is shown by the imaginary modulus’s (M′′) dependence on frequency. The magnetic properties exhibited soft ferrite nature with small hysteresis curve for all spinel ferrites samples. The magnetic properties of MnxFe2-xMg0.5Ni0.5O4 nanoparticles were measured and analysed, including saturation magnetization (Ms), remanence (Mr), coercivity (Hc), and squareness ratio. (Ms), and (Mr), exhibit an increase in their values as manganese substitution (x) increases from 0 to 0.25 mol %, and thereafter decreases while squareness ratio decreased. The magnetic parameters greatly affected by Mn substitution ratio.

Gamma-irradiation-induced tailoring of physical, electrical, optical, and mechanical properties of PVC/PANI/TiO2 nanocomposites for different applications

Gamma irradiation exhibits a complex influence on the properties of PVC/PANI/TiO2 nanocomposite films. XRD analysis reveals a non-monotonic response in crystallinity, with an initial increase at lower doses due to crosslinking followed by a decrease at higher doses attributed to polymer chain scission. Mechanical properties exhibit an improvement in tensile strength and Young's modulus at moderate doses (up to 100 kGy) due to crosslinking. However, excessive irradiation (>100 kGy) induces chain degradation, causing a decrease in both tensile strength and elongation at break. Similar dose-dependent behavior is observed in thermal properties, with moderate doses improving thermal stability and melting temperature before a decline at higher doses due to chain degradation. Gamma irradiation significantly affects AC conductivity, suggesting potential changes in structure, charge carrier density, and conduction mechanisms. While the core chemical structure remains largely unaffected, FTIR and UV–Vis spectroscopy analyses indicate alterations in the degree of crosslinking and optical properties, warranting further investigation. Refractive index increases with irradiation due to enhanced density and changes in polarizability. This study highlights the importance of tailoring the gamma irradiation dose to achieve desired properties in PVC/PANI/TiO2 nanocomposite films for various applications.

Effect of rare earth (Ho and Er) co-substitution on the magnetic and dielectric properties of nanocrystalline cobalt ferrites

Nanocrystalline cobalt ferrites co-substituted with rare earth Ho and Er (CoFe2-2xHoxErxO4, 0 ≤x≤0.10) have been synthesized via the sol-gel method. X-ray Diffraction (XRD) confirmed the single-phase spinel structure with reduced crystallite sizes (65 nm–12 nm), micro-strain (ε) and increased lattice constant (a) with Ho–Er co-substitution. Rietveld refinement and theoretical computation revealed Ho and Er occupancy at octahedral sites and Fe and Co ions redistribution between the tetrahedral and octahedral sites. Infrared spectroscopy, Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray spectroscopy (EDX) and X-ray Photoelectron Spectroscopy (XPS) supported the formation of the desired spinel structure, aggregated spherical morphology, chemical stoichiometry and elemental states. Magnetic measurements showed a systematic decrease in saturation magnetization (Ms), magnetocrystalline anisotropy (K1), coercivity (Hc) and Curie temperature (Tc) with Ho–Er co-substitution. Electron Spin Resonance (ESR) exhibited asymmetric resonance peaks, reduced resonance field (Hr), linewidth (ΔHpp) and deviation in Lande g values. Impedance spectroscopy revealed two conduction mechanisms (holes and electrons) with distinct activation energies (EaI and EaII). Modulus spectrum analysis confirmed the thermally activated sample-electrode effects and the Nyquist plots indicated the dominant contribution of the grain boundary resistance to the conduction process. A notable enhancement in the dielectric constant (ε′) was observed with Ho–Er co-substitution. The ac conductivity (σac) followed the Jonscher Power Law (JPL). The temperature-dependent frequency exponent s(T), suggests the existence of two conduction mechanisms: non-overlapping small polaron tunneling (NSPT) and correlated barrier hopping (CBH).

Effect of striae on the high temperature dielectric and electrical properties of lithium aluminosilicate glass-ceramics

Lithium Aluminosilicate glass-ceramics with striae (LAS-WS) and without striae (LAS-WoS) were processed using melt casting technique. LAS-WS and LAS-WoS samples were characterized and found stress birefringence >10 nm/cm and <10 nm/cm, respectively. LAS-WS and LAS-WoS samples were subjected to structural, microstructural, high temperature dielectric and electrical characterization. The presence of striation did not significantly affected the formation of β-spondumene structure during crystallization heat treatment. TEM image confirms the formation of nanocrystals in the glass matrix of lithium aluminosilicate glass-ceramics. The homogeneous distribution of LAS nanocrystals of average size of 3–6 nm is evident from TEM results. Stress birefringence distribution in lithium aluminosilicate glass-ceramic clearly shows the striae formation. Shadowgraphy images confirmed the striae free and striae containing regions in the glass-ceramic. The effect of striae on dielectric properties and AC conductivity was analysed using impedance spectroscopy and it was found that the value of the relative permittivity decreased from 415 (1.2 Hz) to 9.76 (1.2 MHz) for LAS-WoS and from 401 (1.2 Hz) to 10.3 (1.2 MHz) for LAS-WS, respectively. It was found that striae in LAS glass-ceramics influence the electrical impedance and AC conductivity relaxation process rather than relative permittivity. The effect of striae on crystallization and morphology are presented. Both the samples have shown crystallinity of more than 75 %. The electrical conductivity of σ = 2.0 × 10−3 S/cm for LAS-WoS and 2.7 × 10−3 S/cm for LAS-WS at 300 °C as well as σ = 4.6 × 10−3 S/cm for LAS-WoS and 6.9 × 10−3 S/cm for LAS-WS at 700 °C are found to be in good agreement due to increase in the electrical conductivity with temperature. The ionic conductivity of the material due to Li-ion mobility with respect to temperature and electric field and possible mechanism of AC conductivity are discussed. The results presented indicates the potential application of this material that demands high temperature operation of lithium aluminosilicate glass-ceramics.

Comprehensive analysis of Ni0.4Cu0.2Zn0.4Fe2-4xSn3xO4 nanospinel ferrites: Structural, electrical, and dielectric characterization through advanced techniques

This study extensively investigates Ni0.4Cu0.2Zn0.4Fe2-4xSn3xO4(x ≤ 0.10) nanospinel ferrites, denoted as NCZFe2-4xSn3xO4 NSFs, focusing on their structural, morphological, electrical, and dielectric characteristics. Utilizing various techniques such as SEM, EDX, TEM, XRD, and impedance analysis, the research confirms the cubic spinel structure and composition of the nanoferrites. The substitution of Sn4+ ions into Ni0.4Cu0.2Zn0.4Fe2O4 NSFs is explored, with a thorough examination of dielectric and electrical parameters up to 1.0 MHz and temperatures ranging from 20 to 180 °C. Complex impedance spectroscopy is employed to represent these parameters in a logarithmic 3D graph, revealing insights into ac/dc conductivity, activation energies, dissipation factor, dielectric constant, and loss. The study observes adherence to the power-law frequency rule in ac conductivity and highlights the impact of temperature and substitution ratios on grains, grain boundaries, and elemental composition. The investigation suggests a conduction mechanism involving electron and polaron hopping, and ionic contributions. Dielectric parameters show frequency-dependent changes that relate the dielectric constant to space charge polarization, inhomogeneous dielectric structure, impurities, and grains/grain boundaries. Cole-Cole impedance plots display semicircles dependent on substitution ratios and temperature, emphasizing contributions from grains, grain boundaries, and ionic mobilities. The Nyquist plots of Cole-Cole impedance functions further underscore substantial complexity in the conduction mechanism of the substituted NCZFe2-4xSn3xO4NSFs.

Improving the optical and dielectric characteristics of PVA/PVP/PEG/ZnWO4/CdS blends

This work aims to create novel nanocomposite blended polymers by incorporating (1−x)ZnWO4-xCdS into poly (vinyl alcohol) (PVA)/polyvinyl pyrrolidone (PVP)/polyethylene glycol (PEG) blend to employ these nanocomposites in various optoelectronic applications. This study focused on investigating the structural, optical and electrical features of PVA/PVP/PEG/(1−x)ZnMn2O4-xCdS blends. The x-ray diffraction and scanning electron microscope techniques were used to explore the structure and morphology of the formed samples. The structure and percentages of ZnWO4 and CdS in different fillers were performed using Rietveld method. The doped blends exhibited significant absorption of UVA and UVB types. The greatest amounts of absorption were observed when the filler contained 25 % CdS. The direct and indirect optical band gaps of the doped blend became 5.02 and (1.88, 2.37) eV as the amount of CdS became 25 % in the filler sample. The refractive index, optical dielectric constant, optical conductivity, and nonlinear optical parameters are affected by the amount of CdS in the fillers. The fluorescence spectra for the blends affected by the excitation wavelength and amount of CdS in the filler. The maximum energy density of the doped blend was reached when the amount of CdS in the filler reached 25 %. The purities of emitted color in the undoped blend are 83 % and 74 % under excitation wavelengths of 317 nm and 380 nm. The purity of the blend experienced a slight change when loaded with filler samples. As the ZnWO4 doping of the PVA/PVP/PEG blended polymer rose, its electrical dielectric constant and ac conductivity first enhanced and then irregularly declined as the filler's CdS content rose. Incorporating (1−x)ZnWO4-xCdS into the nanocomposite enhanced their optical and electrical properties, making them a potential material for flexible optoelectronic and energy storage uses.

Exploring multifaceted properties of Polypyrrole-Cobalt ferrite nanocomposites: A comprehensive study

The remarkable properties of Polypyrrole (PY) hold immense potential for revolutionizing electronic device technologies. From flexible electronics to high-performance sensors, PY and its nanocomposites offer a plethora of opportunities to engineer advanced electronic components with enhanced functionalities. The properties of Polypyrrole (PY), Cobalt ferrite (CF) and their nanocomposites (PY1, PY2, PY3, PY4) have been explored with increasing amount of Cobalt ferrite. Their synthesis and nano size are confirmed by X-ray diffraction and Fourier transform infrared spectroscopy. SEM confirmed the Walnut morphology of PY and it is maintained in nanocomposites but size of particles has been increased. Consequently, optical band gap (Eg) and thermal stability of samples observed from UV-Visible Spectroscopy and Thermogravimetric analysis get affected. A. C. Conductivity shows the dispersive nature and a significant increase can be seen from PY1 to PY4 i.e. ac conductivity increases with cobalt ferrite composition into the nanocomposites. Dielectric losses were explained using polarization effect and conductivity values of materials. Diamagnetic nature of PY changes into ferromagnetic in the nanocomposites. Electrodes of each sample were prepared using slurry method and their electrochemical analyses were done in 2 M KOH solution. By enhancing thermal stability, electrical conductivity, and capacitance while simultaneously reducing the optical band gap, the integration of Cobalt ferrite into the PY matrix unlocks new avenues for electronic device design. These advancements pave the way for the development of more efficient and sustainable electronic devices.

UV-Irradiation Effects on the Structural, Optical and Electrical Characteristics of Soft Blended Polymeric Materials Loaded with Multi-Walled Carbon Nanotubes (MWCNTs)

Undoped and doped polyvinylpyrrolidone/carboxy-methyl cellulose/zinc sulfide/nickel oxide (PVP/CMC/ZnS/NiO) nanocomposite blends with multi-walled carbon nanotubes (MWCNTs) were prepared using sol-gel and solid-state reactions and casting techniques. Various blends were formed and their composition and morphologies were characterized using X-ray diffraction (XRD) and scanning electron microscope (SEM) techniques. The structures of the nano-fillers were examined using the XRD technique. The influence of the concentrations of MWCNTs on the linear and nonlinear optical parameters of PVP/CMC/ZnS/NiO nanocomposite blends was examined. The optical band gap energies were decreased from (direct, indirect: 5.31, 5.06) eV for undoped blends to 4.38 and 3.34 eV for the blends doped with the highest concentration of MWCNTs (0.15 wt%). The refractive indices of the various blends were calculated based on the obtained optical band gap energies using various models. The effect of MWCNTs concentrations on the dielectric constants, energy density, electric modulus and ac conductivity at room temperature of the PVP/CMC/0.5ZnS-0.5NiO/x wt% MWCNTs samples were explored using an Inductance, L, Capacitance, C, and Resistance, R (LCR) meter bridge.

Structural and dielectric analysis of Cu-doped NiCo2O4 nanoparticles synthesized by green synthesis approach

The synthesis process of nanoparticles profoundly influences the chemical and physical properties of materials. Green synthesis, utilizing plant extracts as precursor materials, presents an environmentally friendly approach for producing metal oxide nanoparticles. In this study, we synthesized copper-doped nickel cobaltite (Ni1-xCuxCo2O4, x = 0.5) nanoparticles via a green synthesis method employing aloe vera leaf extract. Analysis of the XRD pattern revealed the formation of cubic spinel Ni0.5Cu0.5Co2O4 nanoparticles well-crystalline in nature (space group: Fd-3 m), free from secondary impurity phases. Crystalline size, determined using Debye Scherrer, modified Scherrer, and Williamson-Hall models, yielded values of ∼ 27 nm, ∼ 35 nm, and ∼ 62 nm, respectively. Dielectric studies conducted at room temperature revealed a frequency-dependent increase in dielectric constant. At lower frequencies, tangent loss (tan δ) showed higher values, which gradually decreased as frequency increased. Additionally, the AC conductivity demonstrated a significant increase with higher external field frequencies.

Developing polymer nanocomposite films of ZnO/NiFe2O4 nanohybrids, polyvinyl pyrrolidone, and chitosan for flexible electromagnetic applications and energy storage devices

The present study used ultra-sonication approach to manufacture ZnO/NiFe2O4 (ZNF) and casting technique to prepare ZnO/NiFe2O4–Cs/PVP nanocomposite films. The successful creation of these nanocomposites with a significant decrease in the % crystallinity of the polymer blend with doping agent was verified by XRD results. ZNF and the Cs/PVP chains interacted in the polymer nanocomposites, as seen by the spectra of the FTIR. To determine the direct and indirect optical band gaps, tauc graphs were studied using data from UV–Vis analysis. The results indicate that while the Urbach energy was found to increase, the optical band gaps decreased as the weight percentage of the nanofiller increased. Using a thermogravimetric approach, the thermal stability of the produced PNCs has been investigated. Conductivity experiments demonstrated that when the nanofiller ZNF content increased to 2.5 wt%, so did AC conductivity, the dielectric loss, and the dielectric constant. The correlation between the mechanism of conduction and the amount of nanoparticles indicates that an increase in the percentage of ZNF in nanocomposites could increase their conductivity, with values ranging from 3.72 × 10−12 for pure blend to 7.72 × 10−8 S/cm for 2.5%ZNF-Cs/PVP at 100 Hz. The dielectric measurements for the nanocomposite films showed an increase in dielectric losses and dielectric constant, which is indicative of the films' enhanced dielectric polarization. The results of characterization point to possible uses of these polymer nanocomposites in flexible optoelectronic and magneto-electronic applications and energy storage devices.