Ac Conductivity Research Articles

From experimentation to prediction: comprehensive study of dielectric properties through experimental research and theoretical modeling

This study discusses the experimental findings on the frequency & temperature influences on the dielectric (constant (ε1) and loss (ε2)) of some chalcogenide materials based on Se83Bi17 composition performed in the temperature range 303 K–393 K and frequency range (100–1000000 Hz). As the frequency increases, multiple polarization mechanisms contribute to the reduction of the dielectric constant. The addition of germanium (Ge) to a composition increases ε1 more than tellurium (Te). The dielectric loss decreases with frequency while increasing with temperature and AC conductivity. Understanding these behaviors is important for material characterization and applications in fields like electronics and solar cells. The theoretical section introduces adaptive neuro-fuzzy inference systems (ANFIS), which are utilized in the estimation of the dielectric characteristics of Se83Bi17 (SB), Se83Bi17Te5 (SB-T), and Se83Bi17Ge5 (SB-G). Experimentation-related data are a source of input. ANFIS model of the Takagi–Sugeno type has been trained. With MATLAB, the most effective networks are created. The outcomes of the ANFIS modeling are exceptional. The accuracy of the modeling process is due to the error values. This study demonstrates that the ANFIS technique can accurately anticipate the dielectric properties of the compositions under consideration when they are formed into thin films. The ANFIS can describe the experimental data of the dielectric (constant (ε1) and loss (ε2)) of some chalcogenide materials for all the mentioned temperatures and frequencies. This leads to using the ANFIS model to produce the dielectric (constant (ε1) and loss (ε2)) of some chalcogenide materials for various temperatures and frequencies which there are no experimental data yet to compare with.

Impact of gadolinium doping on BiFeO3-PbZrO3 for energy storage applications: Structural, microstructural, and thermistor properties

The solid-state reaction technique is used to prepare the Gd-doped BiFeO3-PbZrO3 at concentrations x = 0.05, 0.10, 0.15, and 0.20 with chemical formula 0.5(BiGdxFe1-xO3)-0.5(PbZrO3). Room-temperature XRD data are used to compute structural characteristics, such as dislocation density, microstrain, crystallite size, and percentage of crystallinity. The SEM micrographs indicate the spherical, tightly packed nature of materials with limited porosity. The extent to which the composites work at high temperatures (175–400 °C) as NTC thermistors. Understanding the properties of the NTC thermistor requires the calculation of the resistor constant, sensitivity index, and activation energies. Based on the frequency- and temperature-dependent AC conductivity of the composites, a high density of states was calculated.

Electrical, ferroelectric and electro-caloric properties of lead-free Ba0.85Ca0.15Ti0.95(Nb0.5Yb0.5)0.05O3 multifunctional ceramic

In this study, lead-free Ba0.85Ca0.15Ti0.95(Nb0.5Yb0.5)0.05O3 (BC15TYN5) ceramic has been successfully obtained through the conventional solid-state reaction. It has been found the multifunctionality of the BC15TYN5 ceramic. It exhibits ferroelectric properties, with a significant remanent polarization value of about Pr = 9.36 μC/cm2, and a recoverable energy storage density value of about Wrec = 42.21 mJ/cm3. Additionally, it displays a dielectric permittivity of about ε′r = 7230 around TC = 80 °C, and an electro-caloric strength value of about ξ = 0.12 K mm/kV. It's worth noting that these values surpass those typically found in BaTiO3 ceramics elaborated with similar experimental conditions. Electrical study (impedance, modulus, and conductivity characteristics) is essential for characterizing the BC15TYN5 material, determining its suitability for various technological applications, and optimizing manufacturing processes. The Cole-Cole plots exhibited two relaxations associated with the contribution of the grains and grain boundaries. The relaxation times for both grains and grain boundaries showed temperature-dependent variation following Arrhenius relation. The measured AC conductivity was evaluated by applying the Jonsher power law. Based on the thermal evolution of the exponent S, it was confirmed that the conduction mechanism follows the Correlated Barrier Hopping (CBH) model. These properties make BC15TYN5 ceramic suitable for applications such as dielectric capacitors, ferroelectric random-access memories, electrical energy storage units, and electro-caloric refrigeration systems.

Structural, Microstructural, and Electrical Properties Study of Pb(Sn0.45Ti0.55)O3 Ceramics

We undertook a comprehensive investigation of the the structural, dielectric, and electrical characteristics of Pb(Sn0.45Ti0.55)O3 ceramics prepared using the conventional solid-state route. A meticulous preparation protocol, involving solvating various precursors, was followed by extensive characterization employing X-ray diffraction, scanning electron microscopy, and dielectric studies. The synthesized sample features a single-phase tetragonal structure with P4mm symmetry. Using impedance spectroscopy, electrical transport properties of the polycrystalline Pb(Sn0.45Ti0.55)O3(PST) ceramic were studied in detail. Relaxation and conduction mechanisms of the material were inferred using complex impedance, complex electric modulus, and frequency dependent ac conductivity analysis. Impedance spectroscopy results reveal the range of frequencies in which the grain, grain boundary, and electrode effects are dominant. Above certain temperatures, the imaginary component of impedance (Z//) exhibits some resonant type peaks at different frequencies indicating relaxor nature of the sample. The activation energy obtained for both the relaxation and conduction process indicates the role of doubly-ionized oxygen vacancy in the conduction mechanism of the sample. The dielectric relaxation occurring at low frequency and high temperatures is related to the space charges associated with the ionized oxygen vacancies being trapped at the grain boundaries. The Cole-Cole plots confirm the poly-dispersive nature of dielectric relaxation in the sample.

Effect of calcination temperature on structural, morphological elastic and electrical properties of MgO nanoparticles synthesized by combustion method

This study explores the influence of calcination temperature on the properties of MgO nanoparticles (MgO NPs) synthesized via the solution combustion method. Through X-ray diffraction (XRD) and scanning electron microscopy (SEM), structural and morphological changes were investigated. Elastic and dielectric properties were analyzed using computational tools and impedance spectroscopy. Results show that the prepared nanomaterial is belongs to a cubic system and a space group of F m −3 m. Increasing in the calcination temperature (550 °C and 750 °C) enhances crystallinity, reduces defects, and improves structural uniformity. Elastic properties exhibit notable improvements, with Young's modulus increasing from 356.43 GPa for pristine MgO to 364.6 GPa for MgO calcined at 750 °C. Dielectric studies were conducted in the frequency range from 50 to 5 MHz at room temperature. Dielectric analysis reveals enhanced properties, including increased dielectric constant and AC conductivity with rising temperature. The study emphasizes the pivotal role of calcination temperature in tailoring MgO NPs for diverse applications.

Enhancing the performance of optoelectronic potential of CuO/Al nanoplats in a PVC for medium voltage cables applications

This study investigates the potential of incorporating CuO and Al nanoplates into a polyvinyl chloride (PVC) matrix to enhance the performance of medium voltage cables. The incorporation of nanoparticles into the PVC insulation material aims to improve the electrical, dielectric, and optical properties of the cable. The nanocomposite films were synthesized by dissolving PVC in tetrahydrofuran (THF) solvent and adding a mixture of 5 wt% CuO and Al nanoparticles. Fourier-transform infrared spectroscopy (FTIR) analysis confirmed the successful incorporation of the nanoparticles into the PVC matrix. The optical properties of the PVC/AlNPs and PVC/CuONPs + AlNPs nanocomposite films were characterized, revealing a decrease in band gap energy (4.35 eV) and Urbach tail energy (0.3702 eV) for the PVC/CuONPs + AlNPs film compared to the PVC/AlNPs film (4.5 eV and 0.41816 eV, respectively). Additionally, the PVC/CuONPs + AlNPs film exhibited higher absorption coefficients and increased electron delocalization and conjugation (carbon cluster value of 62.53). The dielectric properties of the CuONPs + AlNPs nanocomposites were investigated, with the sample containing 1.5% AlNPs demonstrating the highest AC conductivity (2.029 × 10−3 S/m), dielectric constant, and dielectric loss across the frequency range. Simulations of electric field distribution revealed that the PVC/CuONPs+1.5% AlNPs nanocomposite cable exhibited a more uniform electric field distribution compared to the PVC market cable, contributing to a reduction in electrostatic tension and a relative permittivity increase from 2.25 to 2.35. The electric potential distribution along the cable radius remained similar for both cable samples. These findings demonstrate the potential of nanocomposite insulation materials in enhancing the performance of medium voltage cables, paving the way for improved reliability, longevity, and efficiency.

A comparative study on the effects of multi-walled carbon nanotubes and graphene nanoplates incorporated for improved thermal conductivity and dielectric properties of polyvinyl chloride

In the present work, the improvement in the thermal conductivity and dielectric behavior in the frequency range of 0.025–5 MHz of polyvinyl chloride (PVC) films incorporated with graphene nanoplates (GNs) and multi-walled carbon nanotubes (CNTs) were investigated. The neat PVC and PVC composites consisting of different filler ratios of 0.25, 0.5, 0.75, and 1 wt% were synthesized using the casting technique. The increase in the concentration of GNs or CNTs up to 0.75 wt% enhanced the dielectric constant, ac conductivity, q-factor, F-factor, thermal conductivity, and total impedance of PVC composites. The values of the investigated parameters are slightly higher for PVC-CNTs composites compared to PVC-GNs composites. A further increase in concentration to 1 wt% reduces these parameters, but still more than PVC consisting of 0.5 wt% fillers. The mechanism of correlated barrier hopping (CBH) could be successfully used to describe the AC electrical conductivity of both PVC-GNs and PVC-CNTs composites thin films. Furthermore, the glass transition and decomposition temperatures were determined and found to be dependent on the filler ratio and type, and the thermal stability was increased after adding the GNs or CNTs nanofillers. These findings have drawn special attention to developing PVC composites that can be used in various industrial fields including flexible and wearable technologies, power devices, supercapacitors, electric vehicle battery systems, and aerospace components.

Investigation of Morphology, Optical and Electronic Ac Conduction of the Olivine Manganite Compound: NaMnPO4

AbstractThe evolution of multifunctional materials is an outstanding research area, which aims to improve the versatility of materials according to their broad domains of usage. Focus interest was paid here to the orthophosphate compound, in particular, the olivine NaMnPO4 material. This compound was synthesized by a solid‐state method and investigated using numerous techniques. Primary room‐temperature structural analysis evidences the sample synthesized in the orthorhombic structure and its phase purity. The sample‘s average grain size was calculated to be around 420 nm. Further, the band gap for our material was found to be (Eg=4.4 eV) by optical analysis of UV‐visible spectroscopy, revealing that our compound is a potential candidate for optoelectronic applications. The electrical behavior study‘s main results confirm the ferroelectric character of the sample and support the aim of deepening the knowledge of the material according to its thermally stimulated conduction processes through impedance spectroscopy. Electrical studies revealed the dominant transport processes across various temperature and frequency ranges, leading to the NSPT model. The frequency dependency relates to frequency‐dispersive dielectric spectra, conduction mechanisms, and relaxation phenomena. The obtained results show perspective and suggest that the material under study has a wide range of potential electronic applications.

First principles study on the effects of Li deintercalation on the structural properties of a novel mixed transition metal cathode material LiNi0.75Mn0.125Fe0.125PO4 and investigation of its electric properties

Identifying and developing new cathode materials for Lithium-ion batteries (LIBs) that can achieve the desired balance between performance and environmental requirements is very challenging. Some of the key factors being highly considered in those searches include energy density, voltage, structural stability, cost, and abundance. In this work, ternary doped cathode material LiNi0.75Mn0.125Fe0.125PO4 was synthesized using sol gel method. The structural analysis using Rietveld refinement showed an orthorhombic structure with Pnma space group. The DFT + U calculations were investigated to study the structural and electronic properties during Li deintercalation in Li1-xNi0.75Mn0.125Fe0.125PO4 (0 ≤x ≤ 1). It was found that the material remained structurally stable throughout the deintercalation process. During deintercalation, the Li1-xNi0.75Mn0.125Fe0.125PO4 showed a semiconducting nature for x = 0 and x = 0.25, respectively with Eg = 1.75 eV and 0.57 eV. Then, the material becomes semi-metal for x = 0.5 and x = 0.75 and returns to the semiconducting behavior for x = 1 with Eg = 0.38 eV. The formation energy calculations indicated that the material formed a solid solution throughout the Li concentration range (0 ≤x≤), with values ranging from −17 eV to −1 eV. The voltage decreases from 4.7 eV to 3.4 eV during deintercalation. The Nyquist plot showed the presence of different relaxation processes for LiNi0.75Mn0.125Fe0.125PO4 material. A semiconducting behavior was confirmed. The ac-conductivity as a function of frequency follows the double Jonscher power law. A low dissipation factor was observed, which also decreased with frequency. This shows that LiNi0.75Mn0.125Fe0.125PO4 material could be a good cathode for LIBs.

Wet synthesis of magnetically retrievable Mn/Nd co-doped cobalt ferrites for visible light-driven photocatalytic annihilation of azo dye

In this study, a surfactant assisted wet-chemical method was used to synthesize manganese and neodymium co-doped cobalt ferrite [Co1-xFe2-y O4 (x = Mn, y = Nd)]. The co-doping strategy was adopted to enhance the magnetic properties, tune the band gap, and hamper charge–recombination in the spinel ferrite during the photocatalytic application. Different dopant concentrations, namely Mn = Nd = 1.1 %, 2.2 %, 3.3 %, and, 4.4 %, were used to synthesize MNCF-1, MNCF-2, MNCF-3, and MNCF-4 samples, respectively. The pristine (CF) and co-doped samples (MNCF) were characterized via TGA, PXRD, Raman, FTIR, and UV/Vis techniques to examine the impact of co-doping on the various physicochemical and thermal properties. The optical study proposed the MNCF-4 sample with a band gap value of 2.88 eV as most suitable for visible-light harvesting. A dielectric study showed that co-doped ferrite with a higher dopant concentration (MNCF-4) exhibits boosted AC conductivity and substantially decreased leakage current as compared to the bare and co-doped samples. As the concentrations of the co-dopants increase, the coercivity field (Hc) decreases while the remanent magnetization (Mr) and saturation magnetization (Ms) increase. The MNCF-4 material exhibited the highest magnetic properties, ensuring its full and quick magnetic recovery at the completion of the photocatalytic process. In the context of photocatalytic applications, it was observed that the MNCF-4 catalyst exhibited a mineralization rate constant value of 0.016 min−1 for 92.5 % crystal violet (CV) dye. To mitigate the impact of dye sensitization, the photocatalytic efficiency of MNCF-4 material was assessed by using phenol as a representative colourless organic pollutant. The enhanced magnetic properties of the MNCF-4 catalyst enable its complete magnetic recovery and 90.2 % retention of the photocatalytic activities after five reusability tests.

Multiple relaxation mechanisms in SrBi2Nb2O9 ceramic tweaked by tin and samarium incorporation in assistance with single-step microwave sintering

Non-stoichiometric lead free polycrystalline Sr0.8Sn0.2Bi1.75Sm0.25Nb2O9 (SSBSN) ferroelectric ceramics were synthesized through conventional solid step route method by incorporating ball milling and microwave sintering method. X-ray diffraction along with the Rietveld refinement technique confirms the single-phase orthorhombic structure with A21 crystal symmetry. Additionally, the short-range ordering was confirmed by Raman spectroscopy. Doping induced crystallite size and strain were further calculated from the Williamson-Hall plot, which comes around 150 nm and 1.48 × 10–3 respectively. A plate like morphology with an average grain size of 0.41 μm was confirmed by scanning electron microscopy (SEM). A diffuse type ferroelectric to paraelectric phase transition was recorded at 395 °C, mostly arising due to structural heterogeneity at the inter-ferroelectric phase boundary. The temperature and frequency-dependent dielectric measurement of SSBSN ceramic reveal a Maxwell–Wagner relaxation, with prominent dielectric loss in a low frequency regime perhaps due to the generation of leakage current in the SSBSN system. Frequency dependent ac conductivity indicates the polaron assisted hopping mechanism in SSBSN, which further obeys Jonscher’s formulation. The intra and intergranular contributions to impedance in SSBSN ceramics were probed by the complex impedance spectroscopy (CIS) technique. A non-Debye type relaxation mechanism in SSBSN ceramics was indicated by the Cole–Cole plot, whereas the conduction mechanism and transport properties were briefly studied using modulus spectroscopy.

Synthesis of nickel-cobalt ferrite/graphene oxide nanocomposites

Current investigation is an attempt to study the structural, optical, magnetic and dielectric properties of Ni0.5Co0.5Fe2O4/graphene oxide (NCF/GO) nanocomposites. NCF/GO nanocomposites were synthesized through the ultrasonication technique. NCF nanoparticles (NPs) and GO (with varying weight percentages of GO) were synthesized through sol–gel auto-combustion and modified Hummer’s method, respectively. The effect of nickel–cobalt ferrite NPs incorporation on graphene oxide was studied using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, ultraviolet–visible (UV–Vis) spectroscopy, field emission scanning electron microscopy (FESEM), vibrating sample magnetometer (VSM) and Impedance Analyzer. electrical and dielectric measurements. XRD and FTIR studies showed and confirmed the formation of both spinel for the NCF NPs and amorphous graphene oxide for NCF/GO nanocomposites. The crystallite size and lattice parameter for NCF NPs were found in the range of 21–47 nm and 8.33–8.36 Å, respectively. The optical band gap was found in the range of 1.73–1.83 eV with increasing GO concentration. VSM studies revealed that the saturation magnetization (Ms) value for NCF/GO nanocomposites is found to be decreased from 59 emu/g (for NCF) to 30 emu/g (for 60 wt% of GO) with increased GO weight percentage. There was a drastic variation observed in the value of coercivity (Hc) for NCF and NCF/GO nanocomposites. However, it remains almost constant within NCF/GO nanocomposites. Dielectric studies showed the exponentially decaying nature of dielectric constant and loss tangent with logarithmic frequency. Further, the dielectric constant is increased with increasing GO content. A maximum dielectric constant is observed for NCF/GO nanocomposites with 60 wt% of GO. The AC conductivity is found to be increasing with an increase in GO weight percentage and showed its sharply increasing nature at higher frequencies.

The effect of Fe content on the dielectric properties of TlGa(0,999)Fe(0,001)S2 thin films

0,1 % iron containing Thallium Gallium Sulfide (TlGaS2 and TlGa(0,999)Fe(0,001)S2) thin films were deposited by thermal evaporation in the thickness range 20–200 nm. Raw bulk TlGaS2 and TlGa(0,999)Fe(0,001)S2 crystals were produced using the Bridgman technique. Iron (Fe) content was free, and the bonding content of a polarized charged group in the crystal and thin films was detected in the X-ray diffraction patterns. The dielectric characteristics of the thin films were determined by dielectric spectroscopy. The dielectric results showed Fe content polarizing in space-charge characteristics in the 1–100 Hz frequency range. Besides, the position and magnitude of dipolar polarization supported the presence of dipolar polarized charged groups having Fe content. In addition, it was realized that the void density explicitly affects the dielectric constant. The void density decreased toward higher thicknesses, whereas the dielectric constant increased. The ac conductivity results contributed to evaluating the effect of thickness for each thin film. The overall analysis indicated that even a small percentage of Fe (0,1 %) has a remarkable impact on the dielectric properties and electrical conduction of TlGa(0,999)Fe(0,001)S2 thin films. This analysis can provide opportunities to improve the electrical abilities of Thallium Gallium Sulfide (TlGaS2) thin films, which have applications as receivers of visible and infrared emission, X-ray and gamma-ray detectors, neutron detectors, barometers, and piezoelectric photoresistors if the presence of Fe is considered as investigated in TlGa1−xFexS2 thin films.

Influence of Pr3+ ions on structural, photoluminescence, dielectric, and mechanical properties of barium lithium fluoroborate glasses

The influence of Praseodymium Oxide (Pr6O11) on the physical, optical parameters, photoluminescence, dielectric, and mechanical properties for 20BaF2 + 10Li2O+(70-x) B2O3 + xPr6O11 (where x = 0.0, 0.5, 1.0, 1.5 and 2.0 mol %)] glasses was investigated. FTIR spectra of the borate glass network doped with Pr6O11 demonstrate the vibrational modes. The current study found that adding Pr3+ ions to the glass increased the glass density, packing density (VP), oxygen packing density (OPD), and rare earth ion concentration (N). The optical parameters include refractive index molar refraction and molar polarizability, optical transmission, and reflection loss. All the optical parameters increased except optical transmission decreased with the rising of Pr3+ ions in the glass. The photoluminescence emission intensity increased with the concentration of Pr3+ ions. The dielectric constant decreased while AC conductivity increased with the applied frequency, particularly in the high-frequency region. The elastic moduli, including longitudinal, shear, bulk, Young, and microhardness increased with increasing the content of Pr3+ ions in the glass.

Studies on silver-doped magnesium ferrite utilizing the sol–gel process in terms of structure, magnetism, electricity, and electrochemistry

Silver added magnesium ferrite (Mg1-xAgxFe2O4) nanofine grains were prepared by the sol–gel technique from magnesium, silver, and ferrous precursor materials, maintaining the pH value that was subsequently investigated for sensing applications. X-ray diffraction (XRD) analysis of the ferrite samples showed (Mg1-xAgxFe2O4) cubic spinel structure, larger crystallite size, and other characteristics. Using Fourier transform infrared spectroscopy, the active and functional groups with potential stretching analysis were extracted (FTIR). Using an energy dispersive X-ray (EDAX) spectrum and a scanning electron microscope (SEM), the surface characteristics, features, and the samples purity were examined. The magnetic behavior was examined using the vibrating sample magnetometer (VSM) in relation to pertinent parameters like saturation magnetization (Ms), coercivity (Hc), and retentivity (Mr). It was found that the greater Ms in 1.0 is ferromagnetic. The LCR meter was used to estimate the dielectric constants (ε'&ε''), loss (tanδ) with AC conductivity (σAC), and cyclic-voltammetry was used to assess the electrochemical behavior of the samples. A study is conducted on potential polarizations at both ranges of frequencies. The acquired facts are thoroughly analyzed and comprehended.

Temperature and frequency dependence of conductivity, density of states, and dielectric permittivity of ternary metal chalcogenide PbSnSe2 flake

The mechanically cleaved flake of ternary metal chalcogenide PbSnSe2 was transferred onto the interdigitated electrodes to form electrical contacts. The temperature dependent (180 K–250 K) electrical properties were then analyzed employing complex impedance spectroscopy from 2 kHz to 2 MHz. A detailed analysis of Nyquist plots proposed the space charge dependent behavior and negative temperature coefficient of PbSnSe2 flake. The AC conductivity followed Jonscher's power law with s-parameter value being less than unity. The values of s-parameter increased with rise in temperature suggesting the presence of non-overlapping small polaron tunneling (NSPT) in the PbSnSe2 flake. From this NSPT model, tunneling distance, hopping energy, and density of states (DOS) were estimated at temperatures from 180 K–250 K. The dielectric permittivity showed dispersion at lower frequencies and the tangent loss was also found to be directly related to temperature. A single semicircular arc in complex modulus analysis showed the dominance of bulk effect in the material.

Trap states and carrier diffusion lengths in NiO/β-Ga2O3 heterojunctions

We report the electrical properties, deep trap spectra, and diffusion lengths of non-equilibrium carriers in Ni Schottky diodes and NiO/Ga2O3 heterojunctions (HJs) prepared on the same n−/n+ β-Ga2O3 epi structures. The heterojunctions decrease the reverse current of Ga2O3 high-power rectifiers. In HJs, in contrast to Schottky diodes, the capacitance and AC conductance show a prominent frequency and temperature dependence, suggesting the presence of two temperature activation processes with activation energies of 0.17 and 0.1 eV. The deep trap spectra of the Schottky diodes and HJs differ by the absence in the HJ of deep electron traps E2* with level near Ec − 0.7 eV considered to be an important center of non-radiative recombination. This correlates with the observed increase in the diffusion length of non-equilibrium charge carriers in the HJs to 370 nm compared to 240 nm in the Schottky diodes. The diffusion length of charge carriers in p-NiO was found to be quite short, 30 nm. Possible reasons for the observed differences and possible origin of the minority-trap-like feature commonly reported to be present in the deep level spectra of HJs and also observed in our experiments are discussed.

Synergistic effect of gold nanoparticles decorated functionalized carbon nanotubes nanohybrids on the thermal, dielectric, and sensing properties of polyaniline ternary nanocomposites

AbstractThe synthesis of gold nanoparticles reinforced functionalized single‐walled/multi‐walled carbon nanotubes nanohybrid based polyaniline nanocomposites were carried out using in situ polymerization. The chemical interaction and nanostructured morphology of the synthesized nanocomposites are studied using ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, x‐ray diffraction analysis, x‐ray photoelectron spectroscopy, and field emission scanning electron microscopy. Thermal stability of synthesized PANI/Au@f‐SWNTs is boosted by a magnitude of 30°C as compared with the pristine PANI matrix, which is attributed to a strong barrier effect because of the development of tortuous path that resulted from a uniform distribution of Au@f‐CNTs throughout the PANI matrix. For PANI/Au@f‐SWNTs, the AC conductivity and dielectric permittivity are improved by a value of 83.58 S/cm and 1.35 × 10−5 as well as the dielectric loss is reduced by a factor of 0.11 in comparison with the pure PANI matrix at an applied frequency of 106 Hz. PANI/Au@f‐SWNTs and PANI/Au@f‐MWNTs ternary nanocomposites exhibited excellent selectivity toward the hazardous Cr(VI) heavy metal ions in an aqueous medium with a limit of detection of 0.74 and 0.89 μM with a binding constant of 1.028 × 105 and 3.46 × 104 M−1, respectively, that can be selective and sensitive for the detection of Cr(VI) metal ions in water at trace level.

Silver nanoparticles reinforced on silk fibroin/carboxymethylcellulose composite films for electrical applications

This study proposes the fabrication of silver nanoparticles (AgNPs) on silk fibroin-carboxymethylcellulose (SF-CMC) composite films for advancement in electronic device applications. Bombyx mori silk fibroin is a biopolymer that is used as a bio-template in the fabrication of AgNPs. Various silver nitrate (AgNO3) combinations are added to the prepared SF solution to synthesize AgNPs. To develop stand-alone biopolymer-nanocomposite (SF-CMC/AgNPs) films, SF-AgNPs colloidal solution is blended with CMC solution. Ultra Violet – Visible (UV–Vis), Photoluminescence (PL), Fourier Transform Infra-red Spectroscopy (FT-IR), X-ray diffraction (XRD), Transmission Electron Microscopy (TEM) and Atomic Force Microscopy (AFM) have been employed to the prepared SF-CMC/AgNPs composites toevaluate the physical, chemical, structural, morphological, and topographical information of the composite films. Furthermore, the composites are subjected to LCR Hi-tester and electrochemical workstation CH instrument to analyze the AC, DC conductivity, dielectric characteristics, and electrochemical impedance analysis of SF-CMC/AgNPs composites. The UV–visible spectra reveals the formed nanoparticles in spherical shape with average particle size 35–40 nm. XRD reveals the formed AgNPs in face centred cubic (FCC) structure; TEM reveals the average particle size of 35 nm. AC conductivity of the SF-CMC/AgNPs composite found to be 4.0 × 10−4 to 8.04 × 10−4 S/cm. In spite of the presence of AgNPs, measurements of the dielectric behaviourof pure CMC and SF-CMC materials exhibit good dielectric performance. The obtained results demonstrated that the SF-CMCfilms exhibit significant conductivity following AgNPs incorporation and may therefore be used in biosensor and wearable electronic device applications.

Influence of Ni2+ ions on structural, spectral and dielectric properties of Sr–Co spinel ferrites synthesized by sol-gel auto-combustion route

Nickel substituted Sr–Co nano spinel ferrites with composition Sr0.5-xNixCo0.5Fe2O4 (0.0, 0.1, 0.2, and 0.3) were prepared with the help of a sol-gel auto combustion route. The prepared materials were sintered at 800 for four and a half hours. Analysis of XRD confirmed that the material is composed of a cubic spinel structure with a single phase, and its space group is Fd-3m. Rietveld refinement of X-ray diffraction data was done for all prepared compositions using FULLPROF software. As the composition under study contains more nickel than lattice constant, crystalline size, X-ray density, and bulk density decrease. The dielectric properties were observed about frequency. The dielectric properties revealed that dielectric loss, dielectric constant, and ac conductivity decrease with increasing the Ni2+ content. The activation energy (ΔE) was calculated from the slope of Arrhenius plots. The ΔE found in the range of 0.580–0.096 eV. The analysis of XPS was carried out to examine the elemental state of annealed samples. The prepared material is suitable for employment in applications involving high frequencies because the Ni-doped Sr–Co ferrites with the greatest Ni2+ concentration have the lowest dielectric loss, dielectric constant, and tangent loss value.