Dielectric Relaxation Research Articles

High-temperature variable range hopping conduction and dielectric relaxation in CoFe2O4 ceramic

CoFe2O4 ceramic was fabricated using a sol-gel auto-combustion process. The cubic spinel structure with F d −3 m space group symmetry was confirmed through the Rietveld refinement of the XRD pattern of CoFe2O4 sintered at 800 °C for 4 h. The cobalt vacancies at the tetrahedral site were verified by electron density distribution calculated through the maximum entropy method. The impedance spectroscopy study revealed that the grain boundary was dominant compared to the grain in the electrical properties of CoFe2O4. The total dc resistivity was fitted by the variable range hopping (VRH) model, demonstrating that the charge carriers for conduction mechanism confirm to the VRH model. The density of localized states (N(EF)) near the Fermi level was found to be 1.07 × 1019 eV−1-cm−3. The hopping energy (EH) and hopping length (R) of the charge carriers were estimated to be 0.29 eV and 2.28 nm, respectively, at 473 K.

Graphene nanoplatelets anchored into Ag doped spinel CoFe2O4 nanohybrid: Synthesis, structural, electrical, superior dielectric and room temperature induced ferromagnetism performance for high frequency device application

Graphene (GnPs) incorporated Ag-CoFe2O4 nanocomposite was synthesized using a simple solvothermal method using green synthesis method by okra plant extract. The prepared materials were micro-analyzed by X-ray diffraction (XRD) measurements, Fourier transform-infrared (FT-IR) spectra, Field emission scanning electron microscope (FESEM) and transmission electron microscopy (TEM) microanalysis. The average particle size obtained from XRD data was calculated to be 32.6 nm for Ag- CFO nanoparticles and 24 nm for GnPs doped Ag- CFO nanocomposite which was in good agreement with the particle size (in nm) estimated from the FESEM and TEM micrographs. The effective charge carriers transfer from the from Ag- CFO nanoferrites to graphene pallets and in case of GnPs incorporated Ag- CFO nanocomposite and the long-drawn-out recombination of electron–hole pairs were evidently shown by means of room temperature PL measurements. The photocurrent values well support the PL measurements signifying transfer of the electron-hole pairs. Light dependent Electrochemical Impedance Spectroscopy indicates the incidence of a light dependent dielectric relaxation phenomenon. Massive dielectric values with low loss suggest the GnPs doped nanohybrid to be well suited for high frequency device application. Interestingly, incorporation of GnPs alters the electronic configuration of the nanocomposites inducing ferromagnetic interaction.

Effect of k-ion-rich substitution on structural, thermally assisted relaxation processes in Na0.5Bi0.5TiO3 relaxor ferroelectric

Utilizing a complex impedance technique, we employed a probing approach to investigate the dielectric relaxation and electrical transport characteristics in lead-free Na0.5-xKxBi0.5TiO3 compositions (where x = 0.30, 0.35, 0.40, and 0.45). X-ray diffraction and Raman analysis confirmed the tetragonal phase of all compositions. This study affirms the presence of mostly bulk resistive (grain) contributions in the materials. The most notable grain resistance (Rg) was found at approximately 0.8 M ohm-m for the composition with x = 0.45 at a temperature of 500 °C. The increase in Rg strongly supports the role of K+1 as a suppressor of grain growth, leading to an increased presence of grain boundaries with an enhancement in intrinsic breakdown strength. This study validated the occurrence of non-Debye-type dielectric relaxation across all examined compounds with Negative Temperature Coefficient of Resistance (NTCR) type behavior. The pivotal role of oxygen vacancies in the conduction mechanism was affirmed through Arrhenius's theory. Particularly, the most elevated Ea values, 1.37 eV, and 1.48 eV, were observed in the case of x = 0.45 (NKBT-45). The similarity between activation energies derived from conduction and relaxation processes supports that the responsible charge carriers governing electrical transport remain consistent. Moreover, evidence of Polar Nanoregions (PNRs) formation is indicated by the separation observed between normalized Z″(f) and M″(f) peaks in NKBT-45. This observation suggests a transition from long-range conduction to localized dipolar relaxation.

Radiofrequency dielectric spectroscopy study: Effects of pH, hydrogen bond donors and acceptors on the attachment of spectrin skeleton to the lipid membrane of erythrocytes.

Band 3 protein and glycophorin C are the two major integral proteins of the lipid membrane of human red blood cells (RBCs). They are attached from below to a network of elastic filamentous spectrin, the third major RBC membrane protein. The binding properties of the attachments to spectrin affect the shape and deformability of RBCs. We addressed band 3 and glycophorin C attachments to spectrin by measuring the strength of two recently discovered radiofrequency dielectric relaxations, βsp (1.4 MHz) and γ1sp (9 MHz), that are observable as changes in the complex admittance of RBCs in medium. In medium at pH 5.2, and also in media with protic substances (formamide, methylformamide, or urea), the βsp relaxation became inhibited that is attributable to detachment of glycophorin C from spectrin. In medium at pH 9.2, we observed inhibition of γ1sp relaxation attributable to detachment of band 3 from spectrin, as also was seen in media with aprotic substances difluoropyridine, dimethylsolfoxide, dimethylformamide, acetone, sodium tetrakis(4-fluorophenyl)borate), chlorpromazine, thioridazine and trifluopiperazine. The viscogenic cosolvents (glycerol, ethylene glycol, or i-erythritol) inhibited both the βsp and γ1sp relaxations and significantly lowered their characteristic frequencies. Our observations indicate that the glycophorin C attachment to spectrin has nucleophilic centers whose saturation disconnects this attachment and inhibits the βsp relaxation, whereas at band 3-spectrin attachment site, it is the saturation of electrophilic centers that weakens this attachment and inhibits the γ1sp relaxation.

Studies on Structural and Dielectric Relaxation of Disordered Barium Titanate due to La3+ Doping

Studies on Structural and Dielectric Relaxation of Disordered Barium Titanate due to La3+ Doping

Broadband magnetic and dielectric properties of U-type hexaferrite Sr4CoZnFe36O60

Sr4CoZnFe36O60 ceramics with U-type hexaferrite crystal structure were for the first time prepared and their structural, dielectric, magnetic and magnetoelectric properties were characterized. Broadband dielectric spectra (1 Hz −1 GHz) showed giant permittivity due to two Maxwell-Wagner dielectric relaxations whose frequencies follow the Arrhenius law. These relaxations are caused by inhomogeneous conductivity in the ceramic grains and their boundaries. Temperature and magnetic field dependences of magnetization revealed ferrimagnetic phase transition at Tc1 = 635 K and other two magnetic phase transitions at Tc2 = 305 K and Tc3 = 145 K. Magnetoelectric measurement at 10 K revealed only small polarization 35 nC/m2 which has probably extrinsic origin, so the sample is probably not multiferroic. The observed magnetocapacitance effect (-0.8 %) was attributed to the magnetoresistance (-4 %) caused by non-homogeneous conductivity of the ceramics. High-frequency magnetic permeability measured up to 1.8 GHz evidences the Curie-Weiss behavior above Tc2 and Tc3 and two magnetic field-dependent excitations which exhibit anomalies at magnetic phase transitions. We attributed these excitations to the magnetic domain wall dynamics.

Temperature and frequency dependent response of electrical conduction and dielectric relaxation mechanism in CuCr2O4 tetragonally distorted spinel chromite

Herein, the polycrystalline CuCr2O4 (CCO) electro-ceramic was prepared via the sol-gel self-combustion route. The X-ray powder diffraction analysis at room temperature revealed that the CCO chromite was synthesized in a single phase tetragonally distorted normal spinel structure with I41/amd space group. Transmission electron microscopy (TEM) and selected area electron diffraction (SAED) investigated the polycrystalline nature of the compound. The microstructural analysis by field emission scanning electron microscopy (FESEM) explored the surface morphology of micron-sized grains (Gs) distinguished by well-pronounced grain boundaries (GBs) available for electrical response of the material. The color mapping images of elements by energy-dispersive X-ray spectroscopy (EDS) divulged the homogeneous distribution of elements in the compound. The surface chemistry of the compound was studied by X-ray photoelectron spectroscopy (XPS). This information helped in understanding the electronic states of the ions contributing to the electrical networks and mechanisms responsible for the charge transport within the CCO system. The dielectric relaxation and electrical transport properties were analyzed using complex impedance spectroscopy (CIS) over the experimental range of frequency and temperature from 40 Hz to 1 MHz and 243–493 K, respectively. The experimental complex impedance data were analyzed by RGQGRGBQGB equivalent circuit model which resolved the electro-active contributions of bulk and interface of the CCO spinel to its electrical dynamics. The dispersion in AC conductivity was explained by Jonscher's double power law which provided evidence of small polaron hopping (SPH) as a dominant transport mechanism governing electrical conduction in the compound. The temperature-dependent DC conductivity pattern exhibited an Arrhenius-like behavior that followed Mott and Davis's model of SPH. The analysis of complex electrical modulus M*(ω,T) professed the localized and de-localized movements of the charge carriers. The dielectric permittivity response of CCO followed Havriliak-Negami (HN) phenomenology that divulged the existence of non-Debye type dielectric relaxation processes. The interfacial polarization was observed to be accountable for the dispersion in dielectric loss spectra.

Phase Engineering on Amorphous/Crystalline γ‐Fe2O3 Nanosheets for Boosting Dielectric Loss and High‐Performance Microwave Absorption

AbstractTo design and develop efficient microwave absorbents via phase engineering is still less studied. The unique properties caused by constructing heterophase structure hold the potential to strengthen absorbing capability toward microwave radiation. Herein, amorphous/crystalline γ‐Fe2O3 nanosheets (Fe‐H) are carefully fabricated through a controlled annealing process. The matched Fermi levels formed on both sides of the heterophase interface not only provides efficient interfacial polarizations but also facilitates the transport of electrons with less scattering over the whole Fe‐H nanosheets. Thereby, both of the conduction loss and dielectric polarization relaxation are promoted, leading to a strengthened attenuation toward electromagnetic wave radiation. The as‐synthesized Fe‐H sample exhibited a minimum reflection loss of ‐89.5 dB centered at a thickness of 2.00 mm, associated with an effective absorption bandwidth (reflection loss ≤ ‐10 dB) reaching 6.45 GHz. All of these behaviors are superior to its pure amorphous absorbent and bare crystalline counterpart. Furthermore, this heterophase engineering strategy is valid when extended to Co and Ni based oxides, suggesting its universality and generality for promoting microwave absorption. Henceforth, this study indicates a favorable potential of the synthesis and application of amorphous/crystalline materials as heterophase microwave absorbents.

Dielectric relaxation and hydrogen bonding studies of 1-iodobutane 1,4-dioxane mixture using TDR technique

Complex dielectric measurements by using the Time Domain Reflectometry technique between the frequency range 10 MHz to 30 GHz have been accomplished for different concentrations of 1-iodobutane (IDB) and 1, 4-Dioxane (DX) binary mixtures at 5 °C to 25 °C temperatures. Debye model was used to fit the complex permittivity spectra of IDB-DX binary mixture. The Luzar model is applied to calculate the average number of hydrogen bonds in IDB-IDB and IDB-DX molecules. The measured value of hydrogen bond density is found to be maximum for this binary mixture at dioxane concentration VDX ≈ 0.7. To study the dielectric behavior and to observe the modification in the strength of hydrogen bond in the presence of other nonpolar molecule is the main aim of the proposed work. Measurement of Kirkwood correlation factor and Bruggeman factor provide the valuable information regarding the formation of hydrogen bonded molecular multimers and intermolecular interaction in the binary mixture. Information on the molecular interactions in binary mixtures is also provided by the study.

Dielectric relaxation and thermodynamic study of aqueous Glycine using time domain reflectometry technique

Using the Time Domain Reflectometry technique in the frequency range of 10 MHz to 50 GHz, the complex permittivity spectra of Glycine (Gly) with water combination have been determined over the complete concentration range of mole fractions and in temperature range of 10–25 °C. The Cole-Davidson model was used to fit the intricate permittivity spectra for Gly and water.The non-linear least square fit method has been used to compute the static dielectric constant (ε0), relaxation time (τ), effective Kirkwood correlation factor (geff), excess permittivity (ε0E), (1/τ)E excess inverse relaxation time (1/τ)E and Bruggeman factor (fB). An automated density and sound velocity meter, the Anton Paar DSA 5000 M and viscosity with Lovis 2000 M/ME, was used to measure the density, sound velocity, and viscosity of aqueous solutions. FT-IR spectra are used to identify the conformation assessments of hydrogen bonding development between complicated mixtures.

Structural and dielectric relaxation studies of 1, 4, and 1, 3 -butanediol–1, 4-dioxane mixtures using TDR technique

Time domain reflectometry (TDR) was used to examine the complex dielectric permitivity spectra (CPS) of binary mixtures of 1,4, and 1,3 butanediol (BD) with 1,4 Dioxane (Dx) at high frequencies (10 MHz–50 GHz). Both systems show the Cole–Davidson type of relaxation process. The least squares fit (LSF) method is applied to compute dielectric relaxation parameters from the CPS. The interest of the ongoing research is to understand the molecular associations, orientation of electric dipoles, and change in electric dipole density in the liquid mixture with the help of excess dielectric parameters, Bruggeman factor (fB) and the Kirkwood correlation factor for both systems.

Cyclic voltammetric formation of hollow porous γ-MnO2 microspheres as stable electrodes for high-performance supercapacitors

Cyclic voltammetry enables the fast formation of a binder-free γ-MnO2 electrode at room temperature, which features hollow porous microspheres with electrically connected networks. This process leads to a significantly improved supercapacitive performance compared to conventional binder-based MnO2, which requires chemical conversion at high temperature. Compared to amorphous MnO2, the hollow γ-MnO2 microsphere has a higher content of Mn3+, which facilitates the adsorption/desorption of electrolyte ions and redox reactions at the electrode-electrolyte interface. The hollow porous γ-MnO2 exhibits a high specific capacitance of 405 F g−1 at 1 A g−1 and demonstrates excellent rate capability, with a specific capacitance of 250 F g−1 at 50 A g−1. Remarkably, the specific capacitance remains almost unchanged after 3000 charge/discharge cycles at 10 A g−1. The electrochemical impedance spectroscopy confirms that the γ-MnO2 electrode with hollow porous microspheres outperforms its counterpart, due to its shorter dielectric relaxation time (1.4 s), lower contact resistance, and smaller charge and mass transfer resistances. The novel binder-free γ-MnO2 electrode with hollow porous microspheres provides electrically connected networks, large active sites, and rapid ion transport within the pores and crystal tunnels. This enables faster and more efficient charge storage.

Structural, dielectric relaxation and conduction mechanism in Ho-doped Bi0.5Na0.5TiO3 ceramics

Structural, dielectric relaxation and conduction mechanism in Ho-doped Bi0.5Na0.5TiO3 ceramics

Prominent energy storage density and efficiency of Na0.5Bi0.5TiO3‐based ceramics via multiscale amelioration strategy

AbstractEco‐friendly ceramic capacitors gradually become an important section of pulsed power devices. However, the synchronous realization of ultra‐high energy storage density (Wrec > 6 J/cm3) and efficiency (η > 90%) is difficult. Thus, a novel multiscale amelioration strategy in Na0.5Bi0.5TiO3‐based ceramics is proposed to achieve ultra‐high energy storage density and efficiency. The multiscale amelioration strategy for (Na0.5Bi0.47La0.03)0.94Ba0.06TiO3 (NBLBT) ceramic focuses on grain size, bandgap width, and dielectric relaxor behavior, which can be regulated by introducing Sr(Al0.5Nb0.25Ta0.25)O3 (SANT). On the one hand, the refined grain size and increased bandgap width are conducive to improving the breakdown strength. On the other hand, the optimized dielectric relaxation behavior is beneficial to suppress the remanent polarization. Accordingly, an ultrahigh Wrec = 6.89 J/cm3 and η = 90.1% are simultaneously achieved in 0.84NBLBT‐ 0.16SANT ceramic. In addition, the sample synchronously possesses excellent thermal and frequency stability (a variation within 5% in Wrec and η), transient discharge rate of t0.9 ∼ 78.8 ns and a high‐power density of PD ∼ 114.5 MW/cm3. This study provides an effective strategy to further develop pulsed power devices.

Microwave Dielectric Relaxation of Univalent and Bivalent Electrolyte Solutions.

The microwave dielectric relaxation of aqueous solutions of univalent (KCl, NaCl, NaI) and bivalent (CaCl2, MgCl2) electrolytes at concentrations between 0.1 and 1 M at 25 °C was investigated using a vector network analyzer (0.5≤ ν ≤ 40 GHz). The spectra of these electrolyte systems are characterized by a symmetrical broadening of the main relaxation peak and were fitted using the Cole-Cole equation. In our analysis, we provide insights into the underlying physics of the relaxation events at microscopic and mesoscopic scales by using a 3D phase space trajectory that is based on the interactions of the relaxing dipole units with their surroundings and Frohlich's B function. The effect of the solutes on the H-bond network of water with increasing concentration is evident in the microwave dielectric spectra through decreasing dielectric strengths and relaxation times. It was found that the number of perturbed water molecules is higher in the case of bivalent electrolytes and appears to be proportional to the ionic radius. In our approach, the particular dependence between the broadening parameter α and the relaxation times τ reflects the rate of interactions between the elementary dipole units and their surroundings. We provide a quantitative analysis of the level of perturbation caused by the presence of ions in the hydrogen-bond network of water. It was found that the H-bonded network of water is highly perturbed in univalent systems compared to bivalent systems due to weaker bonded hydration shells. Finally, we found significant differences between the dielectric response of NaCl and NaI. The differences, originating in the counterions Cl- and I-, which are characterized by large ionic radii and consequently weaker electric fields in their vicinity, confirm that the effect of weakly hydrated ions should not be neglected in microwave dielectric spectra analysis.

An insight into the effect of carbon nanofillers in glass fibre epoxy nanocomposites through dielectric spectroscopy

Interfacial characteristics of nanocomposites are critical limiting factors in the design of polymer nanocomposites. The nanocomposites have complex structures and play a pivotal role in controlling functional properties. Analysis of interfacial layers in polymer nanocomposites, existing between the polymer matrix and the nanoparticles plays a major role in determining their characteristics. High-frequency analysis of electrical conductivity and dielectric properties of carbon nanofillers which are embedded in an epoxy matrix were analysed using alternating current dielectric spectra. This article provides a correlation between the electrical transport properties and dielectric behaviour of epoxy carbon nanocomposites at different temperatures are investigated with variations in frequency. Electrical transport properties of nanocomposites are primarily dictated by electron tunnelling and matrix, nanofillers conductivity. Dielectric spectroscopy in the frequency range 10 Hz–8 MHz has been performed on epoxy nanocomposites with and without hybrid carbon nanofillers at one weight percentage (2:3 ratio). Dominant dielectric relaxation mode is observed in the base composite at a low-frequency region (≥10 Hz), whereas nanocomposite with hybrid carbon nanofillers is observed to induce two dielectric relaxations in the kHz region. Increase in non-monotonic variations in dielectric spectra makes the nanocomposite suitable for high temperature low sag conductor core, aerospace and cryogenic engineering applications.

Collective and non-collective molecular dynamics in a ferroelectric nematic liquid crystal studied by broadband dielectric spectroscopy.

A great deal of effort has been recently devoted to the study of dielectric relaxation processes in ferroelectric nematic liquid crystals, yet their interpretation remains unclear. In this work, we present the results of broadband dielectric spectroscopy experiments of a prototypical ferroelectric nematogen in the frequency range 10 Hz-110MHz at different electrode separations and under the application of DC bias fields. The results evidence a complex behavior in all phases due to the magnitude of polar correlations in these systems. The observed modes have been assigned to different relaxation mechanisms based on existing theoretical frameworks.

Temperature-dependent hydration behavior of aqueous lysine: an approach towards protein binding through dielectric spectroscopy

Present work reports interaction between water and amino acid lysine for understanding the physicochemical properties that will be useful in the structure formation of protein. The dielectric relaxation of aqueous lysine was systematically investigated over a temperature range spanning from 298.15 K to 278.15 K, encompassing frequencies ranging from 10 MHz to 30 GHz, and across a concentration range of 0.152 M to 0.610 M. Within this study, aqueous lysine revealed the presence of two distinct relaxation modes. The low-frequency relaxation process (l-process) is primarily associated with the relaxation of lysine molecules, whereas the high-frequency relaxation process (h-process) is attributed to water molecules interacting with lysine. Several key dielectric parameters, including static dielectric constant (εj), relaxation time (τj), dipole moment (μj), correlation factor (gj), and the number of water molecules rotationally bonded by solute molecules (Zib), were meticulously determined. These parameters were interpreted in terms of molecular interactions, hydrogen bonding, hydrophobicity, and Lys-Lys binding. Additionally, various thermodynamic parameters such as molar enthalpy (ΔHj), molar entropy (ΔSj), and molar free energy (ΔFj) were calculated to provide further insights into the system’s characteristics and behavior. Communicated by Ramaswamy H. Sarma

Temperature dependent magnetic and electrical transport properties of lanthanum and samarium substituted nanocrystalline nickel ferrite and their hyperthermia applications

Structural, optical, temperature dependent magnetic and electrical properties have been investigated for the nanocrystalline NiFe1.97RE0.03O4 (RE = La3+ and Sm3+) compound. Without any signs of a secondary REFeO3 phase, the Rietveld refinement reveals a single-phase spinel structure possessing cubic symmetry for current samples. The decrease in lattice constant has been observed as a result of RE ions substitution. The TEM micrographs reveal nanosized particles with an average size of 35 ± 3 nm and 32 ± 3 nm for La3+ and Sm3+ substituted samples. EDX spectra of both samples show good compositional homogeneity. HRTEM micrographs of both samples show well resolved lattice fringes and their inter-planar spacing matches with that obtained from the Rietveld analysis of the XRD patterns. The concentration of Fe2+ and Fe3+ ions has been estimated from the XPS spectra analysis and it is found to be ∼ 22% and 78% for NiFe1.97La0.03O4 and, 20% and 80% for NiFe1.97Sm0.03O4 compound. The optical energy band gap for rare earth substituted samples is found to be more than that of pure nickel ferrite. The value of saturation magnetization (Ms) and magneto-crystalline anisotropy constant (K1) estimated from the “Law of Approach to Saturation” equation for rare earth substituted samples are found to be less than that of pure nickel ferrite. However, an enhanced value of coercivity has been observed with RE substitution. ZFC (zero field cooling) and FC (field cooling) DC magnetization curves measured at 100 Oe in the temperature range of 60–400 K reveal a combination of weak and intermediate forms of magnetic interaction between the particles for both samples. Temperature dependent analysis of saturation magnetization and coercivity employing modified Bloch’s law and Kneller’s relation supports the nanomagnetic behavior of both samples. Under an AC magnetic field of 14.92 kA/m and frequency 337 kHz, the SAR and ILP values have been found to be ∼ 331 W/g and 4.22 nHm2/kg for NiFe1.97La0.03O4 and, ∼ 241 W/g and 3.21 nHm2/kg for NiFe1.97Sm0.03O4. The dielectric relaxation data have been analyzed at various temperatures ranging from 40 to 300 0C over the frequency range 100 Hz-1 MHz using electrical impedance spectroscopy. The dielectric constant for rare earth substituted samples is found to be more and their AC conductivity is observed to be less than that of pure nickel ferrite. The analysis of temperature dependent AC conductivity employing Jonscher’s power law suggests that the charge carrier’s conduction mechanism of both samples follows the small polaron hopping mechanism below 200 0C, thereafter; it follows the correlated barrier hopping mechanism. The activation energy estimated by imaginary impedance spectra is found to be 0.411 eV and 0.398 eV for NiFe1.97La0.03O4 and NiFe1.97Sm0.03O4 which is more than that of pure nickel ferrite. The Cole-Cole plots at different temperatures suggest the presence of non-Debye-type relaxation. The modeling of Cole-Cole plots with equivalent circuits for both samples confirms the contribution of both grain and grain boundary in electrical conduction. The estimated stretching exponential factor by fitting the modified KWW (Kohlrausch-Williams-Watts) equation to the imaginary modulus curve reveals relatively more dipole-dipole interaction in NiFe1.97Sm0.03O4 than that of the La3+ substituted sample.

Optical properties and dielectric relaxation of polypyrrole and poly (3-hexylthiophene)

In the present work, polypyrrole (PPy) and poly (3-hexylthiophene) (P3HT) are prepared via oxidation polymerization, and their optical and dielectric properties in comparison with their originating monomers are investigated. The chemical structure of both polymers is confirmed by FTIR spectroscopy. Investigation of the optical properties of the prepared polymers showed that the band gap of PPY is 1.25 eV, whereas that of P3HT is 1.79 eV. In addition, P3HT showed a refractive index of high values in the visible region compared to PPy. Dielectric relaxation of both monomers and polymers was studied in the frequency range of 10–1 ≤ ν /Hz <107 for comparison. Furthermore, temperature dependencies of their electrical properties are investigated. The DC conductivity values of PPy and P3HT are found to be 2× 10–7 S cm−1 and 2× 10–4 S cm−1, at T = 313 K, respectively, which is the ranges of semiconductors and conductors reflecting the remarkable enhancement of conductivity according to the polymerization process. The temperature dependence of the DC conductivity for the monomers and polymers follows the Vogel−Fulcher−Tammann (VFT) equation. The parameters of the frequency-dependent provide basic information for adjustment of the structural properties of the conjugated polymers and finding the theoretical limits controlling the charge transport.