Analysis Of Nyquist Plots Research Articles

Enhancing the Performance of Nanocrystalline SnO2 for Solar Cells through Photonic Curing Using Impedance Spectroscopy Analysis.

Wide-bandgap tin oxide (SnO2) thin-films are frequently used as an electron-transporting layers in perovskite solar cells due to their superior thermal and environmental stabilities. However, its crystallization by conventional thermal methods typically requires high temperatures and long periods of time. These post-processing conditions severely limit the choice of substrates and reduce the large-scale manufacturing capabilities. This work describes the intense-pulsed-light-induced crystallization of SnO2 thin-films using only 500 μs of exposure time. The thin-films' properties are investigated using both impedance spectroscopy and photoconductivity characteristic measurements. A Nyquist plot analysis establishes that the process parameters have a significant impact on the electronic and ionic behaviors of the SnO2 films. Most importantly, we demonstrate that light-induced crystallization yields improved topography and excellent electrical properties through enhanced charge transfer, improved interfacial morphology, and better ohmic contact compared to thermally annealed (TA) SnO2 films.

High-performance Bi2O3 nanoflakes for advanced energy storage applications

In this work, Bi2O3 nanoflakes (NFs) were synthesized using the co-precipitation method. To understand the crystal structure-surface morphology and their functional properties such as optical band-gap energy, specific capacitance and magnetic properties are examined by various analytical techniques including X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), High-Resolution Transmission Electron Microscopy (HRTEM), Vibrating Sample Magnetometer (VSM), UV–Visible Diffuse Reflectance Spectroscopy (UV-DRS), X-ray Photoelectron Spectroscopy (XPS), Raman Spectroscopy, and Cyclic Voltammetry (CV). FE-SEM confirmed the formation of the nanoflakes, while HRTEM verified their monoclinic crystal structure and provided details on the orientation of the lattice planes. XRD result showed distinctive peaks corresponding to the α-phase, indicating a crystallite size of 8.21 nm. Raman and XPS results are also demonstrated formation of the Bi2O3 NFs with their signature bands. VSM analysis revealed the presence of both magnetic and nonmagnetic phases in the Bi2O3 NFs. Optical studies indicated a promising band gap of 1.9 eV, suggesting potential for optoelectronic applications. Surface analysis confirmed the composition of Bi+ and O2− in the NFs. Additionally, electrochemical assessments through CV demonstrated a significant specific capacitance of 537 F/g at 20 mV/s. Nyquist plot analysis suggested an equivalent circuit R(CR)(CR), indicating an optimal fit. Furthermore, we have made the systematic comparison of optical band gap energy of Bi2O3 with reported different nanostructures such as Peanut, needles, rod and flakes and found that the present study nanoflakes offer much lower band energy compared to above mentioned all other morphologies. Due to the obtained lower energy band gap and specific capacitance performance of the Bi2O3 NFs, it is strongly suggested to the advanced energy storage applications.

Strong magnetoelectric coupling in novel Na0.5Bi0.5TiO3–BaFe12-2xCoxTixO19 multiferroic composite

Multiferroic composites of sol-gel synthesized Sodium Bismuth Titanate (Na0.5Bi0.5TiO3) and Co–Ti substituted Barium Hexaferrite (BaFe12-2xCoxTixO19; x = 0.0, 0.5, 1.0, 1.5 and 2.0) in the ratio 3:1 was synthesized through ceramic route. Successful formation of R3c rhombohedral and P63/mmc hexagonal phases corresponding to Na0.5Bi0.5TiO3 and BaFe12-2xCoxTixO19 respectively was confirmed from the XRD and Rietveld refinement pattern. The frequency and temperature dependence of dielectric constant and loss of the composite systems exhibited typical dispersion behaviour which could be understood using the Maxwell-Wagner model. Substituted samples showed enhanced dielectric behaviour where dielectric constant was observed to increase while loss tangent decreased. Using the Universal Jonscher's Power law (JPL), conductivition mechanisms of the composite systems were studied from the ac conductivity behaviour which revealed that the x = 0.0 sample followed Non-overlapping Small Polaron Tunnelling (NSPT) model while the remaining samples followed the Correlated Barrier Hopping (CBH) model. The complex impedance and Nyquist plot analysis showed the enhancement of resistive property in the x≠0 systems. Magnetic hysteresis loop measurements were conducted, and the associated parameters were determined with the assistance of the Law of Approach to Saturation (LAS). Favourable reduction in the magnetic anisotropy was observed indicating the disturbance of magnetic spin structure in the hexaferrite phase. The P-E loops established the novel room temperature multiferroic nature of the composite systems. Significant magnetoelectric coupling was detected at room temperature in all samples, with the x = 0.5 sample exhibiting the highest value of approximately 59.81 mV/cmOe. These desirable properties suggest that the composites may find future device applications as in magnetically tunable energy harvesting devices and self-powered magnetoelectric sensors in the future.

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.

Unveiling the potential of Dy+3 substituted Ni-Zn ferrites: A study of physical, magnetic, dielectric, and microwave properties

Utilizing microwave ferrites as primary materials holds great potential for high-frequency and high-power devices, opening up exciting possibilities for their application in such systems (circulators, phase shifters). The physical, magnetic, dielectric, and microwave properties of Ni0.5‒xDyxZn0.5Fe2O4; x = 0, 0.02, 0.04, 0.06, 0.08 (DNZF) are thoroughly investigated in the present study. XRD analysis confirms the presence of a distinct cubic spinel structure without additional phases. Dy substitution influences lattice constant and crystallite size, showing a clear correlation. Raman spectroscopy reveals a decline in peak intensity and a shift towards lower wavenumbers, indicating changes in cationic distribution upon Dy substitution. Surface morphology analysis shows an increase in average particle size as Dy substitution inhibits grain growth. XPS analysis indicates partial reduction, transforming Fe³⁺ into Fe²⁺. Saturation magnetization initially increases with Dy concentration, reaching a peak value of 69 emu/g at x = 0.02, and then decreases due to the effect of Dy's atomic size on magnetic moments. Real permittivity (ε') and loss tangent (tan δ) initially increase, reaching maximum values at x = 0.02, but decrease with higher Dy concentrations (x>0.04). The Nyquist plot analysis reveals that grain boundary resistance contributes significantly to the overall resistance. Permeability and permittivity analysis in the frequency range of 12.4 - 18 GHz (Ku band) demonstrates that both real and imaginary components of permittivity decrease with Dy substitution. These findings suggest promising prospects for the utilization of Dy-doped Ni-Zn ferrites in high-frequency devices like circulators and phase shifters, indicating their suitability for such applications.

Design of P110 steel wire beam electrode for high temperature and pressure environment and application for revealing corrosion mechanism

PurposeThe purpose of this work is to design the wire beam electrode (WBE) of P110 steel and study its corrosion behavior and mechanism under high temperature and pressure.Design/methodology/approachPackaging materials of the new type P110 steel WBE and high pressure stable WBE structure were designed. A metallurgical microscope (XJP-3C) and scanning electron microscopy (EV0 MA15 Zeiss) with an energy dispersive spectrometer were used to analyze the microstructure and composition of the P110 steel. The electrochemical workstation (CS310, CorrTest Instrument Co., Ltd) with a WBE potential and current scanner was used to analyze the corrosion mechanism of P110 steel.FindingsAccording to the analysis of Nyquist plots at different temperatures, the corrosion resistance of P110 steel decreases with the increase of temperature under atmospheric pressure. In addition, Rp of P110 steel under high pressure is maintained in the range of 200 ∼ 375 Ωcm2, while that under atmospheric pressure is maintained in the range of 20 ∼ 160 Ωcm2, indicating that the corrosion products on P110 steel under high pressure is denser, which improves the corrosion resistance of P110 steel to a certain extent.Originality/valueThe WBE applied in high temperature and pressure environment is in blank. This work designed and prepared a WBE of P110 steel for high temperature and pressure environment, and the corrosion mechanism of P110 steel was revealed by using the designed WBE.

Shining a light on clean energy: A rare earth-combined transition metal sulphide electrode In:SnO2/α-Tb2S3:MnS for photoelectrochemical applications

Transparent conducting rare earth metal electrode was fabricated for photoelectrochemical cells composed of Terbium sulphide and Manganese sulphide using the spin coating technique. X-ray diffraction analysis showed α-Tb2S3:MnS with a 46.9 nm crystallite size. The SEM analysis revealed rod-like elongated structures on clustered particles. X-ray photoelectron spectroscopy was employed to ascertain the core levels of Tb 4d, Mn 2p, and S 2p. The calculated optical bandgap of the composite material was found to be 2.4 eV. Several procedures were implemented to evaluate the electrical efficiency of the photoelectrode within the electrochemical cell. The photocurrent densities of the electrodes utilized in each of the experiments were significantly higher than those observed in the absence of light. At all scan speeds, a rise in photoelectrode specific capacitance was observed in the presence of illumination. The maximum specific capacitance under illumination was determined to be 638 Fg-1, as contrasting to 495 Fg-1 in dark at 5 mVs−1. Research findings indicate that CA exhibited a photocurrent density of 201 mA. The Nyquist plot analysis revealed the cell resistance of 154 Ω and a conductivity of 5.714 × 10−6 Scm−1. Consequently, these outcomes highlight the effectiveness of the photoelectrode for potential use in solar energy conversion systems.

Y2O3 electrodeposited TiO2 nanotube arrays as photoanode for enhanced photoelectrochemical water splitting

Y2O3 deposited TiO2 nanotubes (Y-TNTs) are investigated as photoanodes for efficient photoelectrochemical water splitting. Y2O3 is electrodeposited on TiO2 nanotubes for 5–15 min. The physicochemical and optical properties of Y-TNTs reveal that Y2O3 anchored on the TNTs enhances the visible light absorption. The Y-TNTs show good photocurrent response compared to pristine TNTs. Y2O3 deposition for 10 min on TNTs produces highest photocurrent of 609 μA cm−2 at 1.23 VRHE. Presence of Y2O3 increases the lifetime of the charge carriers as revealed by the Nyquist plot analysis and Mott-Schottky analysis. Y-TNTs-10 min sample shows 2.75 times higher photoconversion efficiency compared to pristine TNTs. Computational analysis shows that Y–TiO2 has negative free energy of adsorption for OER intermediates as compared to bare TiO2 which has positive values. The rare earth metal electrodeposition on TiO2 nanotubes is another approach to improve the photoelectrochemical water splitting activity without distorting the nanotube structure.

Investigation of the Electrochemical Performance of Titanium-Based MXene Hybridisation with Rice Husk Ash (RHA) as an Anode Catalyst Support Material

MXenes possess unique features that are useful for broader industrial development. However, although many different compositions of MXenes have been discovered, little research has been conducted on the optimal synthesis strategy for producing the best MXenes yield. Therefore, substantial work is performed on the synthesis’ structure and property relationship for direct methanol fuel cell (DMFC) applications since MXenes have been successfully hybridised with rice husk ash (RHA). In this study, to produce titanium-based MXene, Ti3C2 nanopowders are added to the rice husk ash matrix to synthesise hybrid RHA/MXene composites (R-MX). Using different weight percentages of MXene hybridised with rice husk ash (2 wt. % R-MX, 4 wt. % R-MX and 6 wt. % R-MX), different electrochemical properties are obtained. Meanwhile, electrochemical analysis is undertaken to investigate the methanol oxidation performance using Linear Sweep Voltammetry (LSV). The highest percentage of the R-MX hybrid composite, 6 wt. % MXene, showed the lowest Tafel slope (148 mV/dec) and the highest ionic exchange current density in the same Tafel analysis. Moreover, the incorporation of MXene into RHA produced good results from the chronoamperometry analysis (CA), with the highest percentage of the hybrid composite, R-6MX, showing the highest retention rate of 97.28%. Meanwhile, the Nyquist plot analysis showed an increasing semicircle arc diameter at the lower-frequency region, implying a lower interfacial charge resistance upon the addition of MXene into RHA. This outcome corresponded to the CA and LSV analysis findings, R-6MX showed a remarkable performance in terms of having the highest peak current density of 0.9454 mA/cm2 and retention rate of 97.28%. Both of these values show that hybrid R-6MX was able to maintain a high current for the entire duration. The current is maintained in a stable form for some time, proving that R-6MX was the most stable, with a minimal corrosion reaction and tolerance in a methanol medium. The results from this study enabled an evaluation of the possibility of utilising low-cost, green RHA material for fuel cell applications to promote sustainability. The novelty of this work is that a cheap source of silica-based RHA, a type of waste material, is incorporated with MXene through hybridisation processes.

A double perovskite BaCaZrMnO6: synthesis, microstructural dielectric, transport and optical properties

In this communication, synthesis (solid-state reaction) and characterization of a double perovskite BaCaZrMnO6 are reported. The Williamson–Hall method is used to compute average crystallite and micro-lattice strain in the prepared sample after structural analysis with X-Pert High-Score software. The sample's microstructural characteristics were investigated using a scanning electron microscope (SEM), and compositional purity was determined using energy dispersive x-ray spectroscopy (EDX). The Raman spectrum displays all atomic modes of vibration, providing information on phase, polymorphic crystallinity, and molecular interaction, as well as confirming the presence of all constituent elements. The ultraviolet visible spectrum research gives good bandgap energy for several optoelectronic devices. The impedance parameters have been measured using an impedance analyzer in a wide range of frequencies (102–106 Hz) and temperatures from 25 °C to 500 °C. The dielectric versus temperature and frequency analysis validates the Maxwell–Wanger type of dielectric dispersion. The impedance spectroscopy investigation indicates that the sample exhibits a negative temperature coefficient of resistance (NTCR), whereas the modulus analysis verifies a non-Debye type of relaxation process. The results of the ac conductivity research confirm a thermally activated relaxation process. Nyquist plot analysis reveals the NTCR character, which is well supported by Cole–Cole plots. The resistance versus temperature analysis supports the NTC thermistor nature, but the polarization–electric field (P–E) loop analysis reveals the presence of ferroelectric character, making it a strong option for temperature sensors and ferroelectric-related devices.

Development of physicochemically stable Z-scheme MIL-88A/g-C3N4 heterojunction photocatalyst with excellent charge transfer for improving acid red 1 dye decomposition efficiency

The MIL-88A/g-C3N4 heterojunction photocatalyst with high physicochemical stability and excellent charge transfer has been successfully developed in this study, and the synergistic effect and the photocatalytic mechanism of the MIL-88A/g-C3N4 composite for Acid Red 1 (AR1) dye decomposition has been discussed in detail. Under simulated-sunlight irradiation, the MIL-88A/g-C3N4 composite showed excellent photocatalytic efficiency for AR1 dye decomposition (100% decomposition efficiency within 30 min for 10 ppm AR1 dye) without the addition of any oxidizing agent, and the composite maintained 97% decomposition efficiency when used repeatedly. The Nyquist plot analysis and the electrochemical analysis results confirm that the improved photo-generated electrons and holes separation and transfer efficiencies of MIL-88A/g-C3N4 could be attributed to the Z-scheme structure formed between MIL-88A and g-C3N4, leading to excellent oxidation efficiency of AR1 dye. The effects of synthesis time of MIL-88A and coupling ratio of MIL-88A on the photocatalytic activity of MIL-88A/g-C3N4 heterojunction composites have been detailed evaluated in this study.

Electrical properties of ceramics based on Ag7TS5I (T = Si, Ge) solid electrolytes

The ceramic samples based on the synthesized compounds of Ag7TS5I (T ​= ​Si, Ge) solid electrolytes were prepared with using of micro- and nanocrystalline powders. Structural studies of powders obtained by grinding in an agate mortar as well as in a planetary ball mill were carried out by XRD and SEM techniques. Optical microscopy was used to estimate the size of crystallites after annealing of prepared ceramics. Temperature (292–383 ​K) and frequency (10 ​Hz–2 ​× ​106 ​Hz) dependences of total electrical conductivity of ceramic samples were investigated by impedance spectroscopy technique. Separation of electronic and ionic parts of electrical conductivity were carried out by the analysis of Nyquist plots using electrode equivalent circuits. The dependences of ionic and electronic components of the electrical conductivity on temperature and on average size of the crystallites were investigated for Ag7TS5I-based ceramics. The comparison of electrical parameters for Ag7TS5I (T ​= ​Si, Ge) crystals, composites and ceramics was performed.

Study of structural, dielectric and AC conductivity properties of SrMoO4

Strontium molybdate (SrMoO4) compound is synthesized using a solid-state reaction route. SrMoO4 was observed to form in tetragonal Scheelite structure with I41/a space group and is confirmed with the help of powder X-ray diffraction studies. The temperature-dependent dielectric constant measured at different frequencies indicated a maximum at around 795 K. The frequency-dependent dielectric maximum reveals the presence of a dielectric relaxation near 795 K. Further, the Nyquist plot analysis shows a depressed semi-circle and manifest the non-Debye type dielectric relaxation in SrMoO4. The SrMoO4 compound possesses a negative temperature coefficient of resistance and is confirmed by fitting the Nyquist plot with a suitable equivalent circuit. The AC conductivity studies ascertain that the observed conduction mechanism in the SrMoO4 as a translational type correlated barrier hopping. The temperature-dependent AC conductivity reveals that the obtained activation energies are comparable with the oxygen vacancies and are responsible for observed dielectric relaxation.

Influence of Cation Substitution on Ionic and Electronic Conductivity of (Cu1 – xAgx)7GeS5I Mixed Crystals

Impedance measurements of (Cu1−xAgx)7GeS5I mixed crystals are carried out in the frequency range from 10 Hz to 300 kHz and in the temperature interval 292–383 K. The temperature and frequency dependences of the electrical conductivity for (Cu1−xAgx)7GeS5I mixed crystals are studied. Based on the analysis of Nyquist plots and using the electrode equivalent circuits, the values of ionic and electronic components of the electrical conductivity are determined. The compositional behavior of the ionic and electronic conductivities, as well as the compositional behavior of their activation energies, are discussed. The ratio of ionic and electronic components of the conductivity for (Cu1−xAgx)7GeS5I mixed crystals was analyzed.

CuS–ZnS decorated graphene nanocomposites: Synthesis and photocatalytic properties

Fabrication of porous nanocomposites was synthesized by incorporating CuS–ZnS nanospheres and graphene layers via a simple method for efficient photocatalytic performance. The transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM) images showed that the as-prepared copper sulphide (CuS) and zinc sulphide (ZnS) nanomaterials are spherical in shape and uniformly dispersed in graphene layers. The strong bonding interaction between as-synthesized nanospheres and graphene layers were analysed by using XRD and XPS analysis. The Raman spectra analysis indicates the shifting of charge carriers between the nanospheres and graphene layers. The insertion of CuS–ZnS nanospheres significantly enhances the surface area, porosity, adsorbability and interplanar distances of the graphene layers due to the better synergistic effect. The formation of a p-n junction on the graphene surfaces was confirmed by Nyquist plot analysis. The photocatalytic degradation of methyl orange (MO) - rhodamine B (RhB) dyes mixture in aqueous solution of as-synthesized nanocomposites was compared with pristine graphene. The nanocomposites show better photocatalytic performance over a wide pH range of 4.45–10.38. The mechanism of photocatalytic degradation was also discussed. The stability and reusability of as-synthesized nanocomposites were also estimated. The obtained results showed the excellent dyes degradation efficiency of as-synthesized nanocomposites due to its excellent surface area, porosity, better UV light harvesting capacity and ultra-fast electron-hole transfer capacity. Hence, CuS–ZnS decorated Graphene is a potential photocatalyst for MO – RhB dyes mixture degradation in industrial applications.

Studies of structural and electrical properties of (Pb0.9Bi0.05Dy0.05)(Fe0.1Ti0.9)O3 ceramic

In this communication, detailed studies of structural, dielectric, and electrical characteristics of dysprosium (Dy)-modified bismuth ferrite–lead titanate (BiFeO3–PbTiO3) solid solution, [i.e., (Pb0.9Bi0.05Dy0.05)(Fe0.1Ti0.9)O3)], prepared by a standard high-temperature solid-state reaction route, have been reported. From the preliminary X-ray structural analysis with Rietveld refinement method, the structure of the material is found to be tetragonal. Detailed analysis of surface morphology, X-ray energy-dispersive spectra and elemental mapping has shown uniform distributions of grains of varying size and elemental composition of the compound. The frequency dependence of the dielectric constant has been explained by the Maxwell–Wagner model. As both the components of the solid solution (BiFeO3 and PbTiO3) have high-temperature ferroelectric transition, no dielectric anomaly has been observed in the said experimental range of our temperature dependence of dielectric studies. The detailed analysis of Nyquist plots, using impedance data collected in a wide range of frequency and temperature shows the contributions of both grains and grain boundaries in the resistive and capacitive characteristics of the prepared material. Both negative and positive temperature coefficients of resistance behaviour are observed in the material. The frequency and temperature dependence of ac conductivity obeys Jonscher’s power law and Arrhenius equation. The occurrence of electric field dependence (P–E) hysteresis loop at room temperature shows the ferroelectric property of the material.

Higher temperature order–disorder transition, electrical and optical properties of [N(C2H5)4]2Pd2Cl6compound

[N(C2H5)4]2Pd2Cl6hybrid compound with semiconducting character was synthetized and characterized by X‐ray diffraction, the thermal, optical and electrical properties. X‐ray diffraction indicates that the compound crystallize at room temperature in the orthorhombic system and (Immm) space group. Two endothermic peaks at, 343 K and 440 K were observed in the DSC measurements corresponding to the evaporation of water molecules and order‐disorder transition, respectively. The optical band gap (Eg= 4.34 eV) was deduced by the Tauc relation. The electrical properties was studied using the impedance spectroscopy in the frequency range of 0.1 Hz to 1 MHz and over the temperature range of 270 K to 480 K. The analysis of Nyquist plots revealed the presence of grains, grain boundaries and the electrode effects. The equivalent circuit was determined. The Ac conductivity was analyzed by the Jonsher low and the conduction mechanism was deduced based in the Elliot theory and indicate that the correlated barrier hopping model (CBH) was described the two regions II and IV and the overlapping polaron model (OLPT) the right model described the conduction in the regions I and III.

Structural, dielectric and electrical properties of BiFeO3 and BaTiO3 modified Bi(Mg0.5Ti0.5)O3

Bismuth barium magnesium ferric titanate (Bi0.5Ba0.5) (Mg0.125 Ti0.625 Fe0.25)O3 is fabricated through a standard ceramic technology route. By using various experimental techniques, the material has been characterized. Study of crystal structure using XRD (X-ray diffraction) data shows the rhombohedral system. Analysis of dielectric study reveals that the compound has low tangent loss and high dielectric constant at room temperature. At low frequencies and high temperatures, the existence of space charge polarization and the Maxwell–Wagner dielectric mechanism in the material has been realized. The existence of ferroelectricity in the material is confirmed by the PE loop. The impedance plots reveal that the compound shows semiconductor (based on negative temperature of coefficient of temperature) behavior at high temperature ≥ 300 °C. Analysis of Nyquist plots reveals the non-Debye type of dielectric relaxation and the contribution of grains and grain boundaries in the resistive and capacitive nature of the material. From the conductivity analysis, it can be seen that the sample obeys the Josher universal power law, and the Arrhenius type of conductivity. The low-leakage current of compound makes it suitable for the high temperature applications, and hence it shows probable Ohmic-type of conduction mechanism.

Studies of electric, dielectric properties, and conduction mechanism of {(C2H10N2)(MnCl (NCS)2)2}n polymer

AbstractDielectric and electrical properties correlated with the structure analysis have been studied for new crystalline polymer {(C2H10N2)(MnCl (NCS)2)2}n. The frequency and temperature dependence of dielectric constant (ε′), dielectric loss (ε″) and loss tangent (tanδ) in the temperature range 308‐348 K and frequency range 20 to 2 MHz have been made for {(C2H10N2)(MnCl (NCS)2)2}n. The Z′ and Z″ versus frequency plots are well fitted to an equivalent circuit model. The analysis of Nyquist plots is well fitted to an equivalent circuit consisting of series of combination of grains and grain boundary elements. The spectra follow the Arrhenius law with two activation energy the first in the region of temperatures before 332 K (Region I) and the second in the region after 332 K (Region II). An agreement between the experimental and theoretical results is discussed, and it is suggested that the ac conductivity can be explained by the correlated barrier hopping (CBH) and nonoverlapping small polaron tunneling model (NSPT) in regions I and II, respectively. The AC conduction mechanism is governed by the correlated barrier‐hopping (CBH) with WM (Region I) = 270 meV and a tunneling distance of 4.5 Å, whereas it becomes a small polaron tunneling mechanism (SPTM) mechanism with a WH (Region II) = 153 meV. The imaginary part of the electrical modulus formalism obeys the Kohlrausch‐Williams‐Watt (KWW) model. The theoretical Kohlrausch exponent (βKWW) confirms the existence of the transition phase on the new crystalline polymer in the vicinity of the 332 K as deduced by the DC and the AC conduction parameters. Thus, the near values of activation energies obtained from the impedance and modulus spectra confirm that the transport is through an ion hopping mechanism.

Impedance spectroscopy and transport properties of polymer-based flexible nanocomposites

The flexible nanocomposites of bismuth ferrite and polyvinylidene fluoride were prepared by the solution casting method. The X-ray diffraction technique confirms the presence of both the inorganic filler (bismuth ferrite) and polymer phases. Atomic force microscopy study shows the increasing values of root mean square (RMS) roughness in the nanocomposites. The modulus and impedance spectroscopy were performed to get insight contribution of grains, grain boundaries, and interfaces on the electrical properties. From the Nyquist plot analysis, grains effect is dominant over the grain boundaries and non-Debye type relaxation behavior is observed for the nanocomposites. Correlated barrier hopping (CBH) model is the most suitable model to explain the transport properties of the charge carriers. The hopping distance increases from 8.11 Å to 27.25 Å with increasing the content of inorganic fillers in the nanocomposites. The presence of the different conduction processes at various temperature regions is explained by the Arrhenius plot analysis.