Ac Conductivity Research Articles

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.

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.

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.

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.

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.

Tailoring electrical properties of PVC/PEC/Co3O4 nanocomposites by electron beam irradiation for advanced medium voltage cable applications

This study aimed to investigate the effects of electron beam irradiation on the structural, optical, and electrical properties of polyvinyl chloride/pectin (PVC/PEC) nanocomposites incorporating hexagonal nanoplate Co3O4. Hexagonal nanoplate Co3O4 was synthesized and incorporated into PVC/PEC blends at 5 wt%. The nanocomposites were subjected to electron beam irradiation at varying doses (0, 10, 20, and 30 kGy). Various characterization techniques, including XRD, UV–Vis spectroscopy, AC conductivity, and dielectric measurements, were employed to analyze the irradiated samples. Additionally, electric field distribution simulations were performed for a 33 kV cable model. XRD analysis revealed the retention of Co3O4 crystallinity up to 30 kGy, while the polymer matrix showed degradation above 10 kGy. The optical bandgap decreased from 2.25 eV to 1.90 eV with increasing irradiation dose, indicating changes in the electronic structure. The optimized AC conductivity (37.17 × 10−6 S m−1) and minimum relative permittivity (2.28) were achieved for the 30 kGy irradiated sample with 5 wt% Co3O4. The electric potential distribution gradually decreased from 33,000 V to zero V. The systematic variations in structural, optical, and electrical properties demonstrated controlled tuning of charge transport mechanisms, making these nanocomposites potentially suitable for advanced cable systems. The simulation results showed that the inclusion of Co3O4 at 30 kGy helped maintain a uniform electric field distribution in the 33 kV cable model compared to an unfilled cable.

Variation of electrical properties with temperature for polyethylene oxide doped with 0.1 wt. % iodine

The electrical properties of thin films made of polyethylene oxide (PEO) dispersed with dopants fixed amount of iodine (0.1 wt. %) were studied using the AC impedance technique. The films were prepared by electrically casting method. In this present work, the variation of AC electrical conductivity with temperatures ranging from 30 oC to 55 oC at a frequency of 200 kHz for (PEO) film doped with 0.1wt. % iodine and undoped (PEO) film were studied. Physical quantities and parameters such as AC conductivity, impedance, dielectric constant, and dielectric loss, were determined. The observed values of the impedance (Z), dielectric constant ('), dielectric loss ("), and AC-conductivity (σAC) showed temperature dependence. It was found that the dielectric constant and the dielectric loss of the prepared thin films increased with doped (0.1wt. %) iodine complexes and also increased with the increase of temperature according to the polarization processes.

Preparation and opto-electrical characterization of poly(ethylene oxide) based polymer blends for electrochemical applications

Solid polymer electrolyte blends with varied compositions of poly(ethylene oxide) (PEO)/carboxymethyl cellulose (Na-CMC) in 10/90, 50/50, and 90/10 compositions have been successfully prepared by means of the solution cast technique at room temperature. The modification of the structural, optical, and electrical properties of the prepared blend samples was studied by employing XRD, FTIR, UV-Vis, and electrical impedance spectroscopy methods. X-ray diffraction studies revealed that the crystalline nature gradually transforms into amorphous as the Na-CMC content increases in the sample. The variation of bands noticed in the Fourier transform infrared spectroscope characteristic spectrum of the blends reveals the formation of complexes between the individual polymers. The analysis of optical properties using a UV-Vis spectrometer in the wavelength range of 900–1100nm, shows a gradual decrease in the optical indirect energy band gap with an increase in Na-CMC content in the blend. The study of the electrical properties of the blend carried out in the frequency range 50 Hz–1MHz and temperature range 303K–338K, using an electrical impedance analyzer reveals that, the dielectric constant and loss decrease with the rise in frequency, exhibiting the usual behavior of the polymers. AC conductivity is found to increase with an increase in temperature. The highest value of ionic conductivity is found to be 6.06 × 10−3Scm−1 for the blend with a 10/90 composition.

Investigation of the relationship between morphology-electrical transport phenomena in iron-doped quaternary glass nanocomposite

The Fe doped nano nanocomposite glassy system xFe·(1-x)·(0.3 V2O5·0.2MoO3·0.4CdO·0.1ZnO) (x = 0.2, 0.3, and 0.4) has been studied by different techniques. Lattice strain (ɛ) increases with increasing iron (x) content in the glass system, which facilitates the enhancement of electrical phenomena such as transport using the polaron hopping mechanism. The AC conductivity spectra at different temperatures have been computed using Almond–West formalism and a modified correlated barrier hopping model. AC, as well as DC conductivity, have increased with increasing Fe content in compositions. The DC activation energies are found to be 0.53, 0.48, and 0.44 eV for the values of x = 0.2, 0.3, and 0.4 respectively. Both DC activation energy (Eσ) and activation energy (EH) for hopping frequency have decreased with Fe content. AC conductivity scaling data has explored that the common electrical relaxation mechanism is temperature-independent as well as composition-dependent.

Optoelectronic properties of fluorine and antimony-doped tin dioxide nanoparticles

Nano-sized tin dioxide SnO2 (TO) has garnered great potential for use in optoelectronic applications, gas sensors, and solar cell technology thanks to its unique properties. These properties can be further enhanced by altering dopants and crystallinity. To achieve these aims, we successfully synthesized nanoparticles of fluorine (F) and antimony (Sb) doped tin dioxide by using a modified sol-gel method. The synthesis process involved supercritical drying of ethyl alcohol. The effect of doping on TO sample microstructure, optical and electrical properties was studied, which is crucial to understanding its potential applications. The X-ray diffraction pattern reveals that the nanoparticles crystallized in the tetragonal rutile structure with a size varying from 22 to 25 nm depending on element doping. The structural analysis was further proved by Raman spectroscopy and FTIR investigations. The optical band gap energy decreases upon the doping, as evidenced by the Eg values of 3.88, 3.87, and 3.72 eV corresponding to, FTO, and ATO respectively. This result proves that our compounds are good candidates for optoelectronic applications. Further, the electrical properties proved the semiconductor behavior for all the samples. Its conductivity is thermally activated, with a decrease in activation energy observed upon the addition of dopants. Moreover, the temperature dependence of the exponents's’of the (ac) conductivity proves that the conduction mechanism varies with dopants. The decrease of s values for undoped and FTO samples revealed a dominant correlated barrier hopping, while the increase of ‘s’ for ATO confirmed the tunneling hopping mechanism. Furthermore, the representation of real and imaginary parts of impedance has also been analyzed. Thus, the obtained results open exciting opportunities for using these samples in many fields that foster the combination of optical and electrical properties.

Investigating the effects of Mn content on the morphology and dielectric properties of CdS nanoparticles

CdS nanoparticles doped with Mn were synthesized by chemical precipitation using varying concentrations of Mn at Cd1-xMnxS, where (x) = 0.00, 0.03, 0.05, and 0.07. The samples were examined using scanning electron microscopy (SEM), energy dispersive X-ray techniques (EDX), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, dielectric properties, and AC conductivity measurements. SEM micrograph shows that pure CdS nanomaterial has agglomerates primarily composed of nanoparticles, whereas the sample with a concentration of 0.03 contains smaller particles. In response to the phonon confinement effect, The Raman spectra of CdS nanoparticles exhibited peaks at 303 cm−1 and 603 cm−1. In contrast, the Raman spectra of Mn:CdS nanocomposites displayed a prominent fundamental mode at 301 cm−1 and a less pronounced overtone mode at 601 cm−1. The dielectric properties and the AC conductivity of CdS have been investigated over a wide frequency range of 0.1 Hz to 10 MHz and at a variety of temperatures ranging from 298 to 423K. The real and imaginary parts of the complex dielectric constant (εʹ, εʹʹ), the electric modulus, and AC conductivity of CdS were found to depend on Mn content at different temperatures.

Development of High-Performance Polyindole/Silicon Carbide Nanocomposites for Optoelectrical and Sensing Applications.

In this study, silicon carbide (SiC)-reinforced polyindole (PIn) nanocomposites were prepared by a simple in situ polymerization method. The successful reinforcement of the nanofiller within the host matrix was characterized using different analytical techniques. The chemical bonding of SiC in the polymer was identified by the characteristic peak around 800 cm1 using Fourier transform infrared spectroscopy (FT-IR). The increment in intensity of the absorption and enhanced crystallinity of the samples upon the addition of nanofillers were analyzed using UV-vis spectroscopy and X-ray diffraction (XRD). The prepared specimens showed reduced optical bandgap energy (3.188 eV) and Urbach energy (2.315 meV) with an improved refractive index (2.348). The effect of nanoparticles on the surface morphology of the nanocomposites was studied using scanning electron microscopy (SEM), and a uniform dispersion of fillers in the matrix was found for PInSiC7. A high-resolution transmission electron microscopy (HR-TEM) revealed the shape and average particle size of the sample. X-ray electron spectroscopy (XPS) measurements confirmed the formation of the nanocomposite by exhibiting the presence of all elements in the corresponding spectra. The thermal stability and glass transition temperature of the nanocomposites were significantly improved with the addition of SiC. The temperature-dependent AC conductivity, dielectric parameters, complex impedance, and electrical modulus were also evaluated using an impedance analyzer. The increased electrical characteristics of the PInSiC7 sample can be attributed to the uniform spread and strong synergetic interaction of SiC with PIn. The results thus showcased the potential of the samples for use in optical and energy storage applications. This study was also extended to understand the ammonia sensing properties, which make it possible to design and develop gas sensors using the PInSiC nanocomposites.

Reinforced PEO/Cs polymers blend with Al2O3/TiO2 hybrid nanofillers: Nanocomposites for optoelectronics and energy storage

This work focuses on the meticulous preparation and characterization of polyethylene oxide (PEO)/chitosan (Cs) polymer blends infused with aluminum oxide nanoparticles (Al2O3 NPs) and sol-gel synthesized titanium oxide nanoparticles (TiO2 NPs). Employing the casting method, the study delves into a comprehensive analysis of the structural, optical, electrical, and dielectric properties exhibited by the resulting PEO/Cs-Al2O3/TiO2 nanocomposites. Structural evaluations utilized transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FT-IR). UV–Vis spectra showed enhanced optical properties, with the indirect optical energy gap decreasing from 5.23 eV to 5.01 eV for blends with 2.4 wt% Al2O3/TiO2 NPs. The AC conductivity of the polymeric nanocomposites showed enhanced values compared with the pure blend. Additionally, dielectric permittivity and modulus exhibit tunability, presenting advantageous prospects with varying Al2O3/TiO2 NPs concentrations in the PEO/Cs blend. The Nyquist plots reveal distinctive features, including semicircular arcs at the low-frequency part and an inclined spike at the high-frequency part, with decreasing arc radius corresponding to increasing nanofiller contents. These observations are best fitted to two models of equivalent circuits. The engineered PEO/Cs-Al2O3/TiO2 nanocomposite capacitor showed enhanced storage capacity and controlled conductance characteristics. The findings of this study revealed that these nanocomposites hold promise as bandgap tuners, optical sensors, permittivity-tunable nanodielectrics, and novel host matrices for the development of solid polymer flexible electrolytes, thereby contributing to the next generation of energy storage and conversion devices with superior performance.

Influence of Zirconium substitution on electrical properties of Nickel-Zinc Ferrites

The Zirconium substituted Nickel Zinc Ferrite nano particles with chemical composition of Ni(0.5-x)Zn(0.5-x)ZrxFe2O4, where the value of x varies from 0 to 0.2, have been synthesized by the sol-gel auto combustion method, using high purity nitrates and fuelling agent citric acid. The structural property was studies from X-ray diffraction spectra. The crystallite size decreases with increase in Zirconium substitution. The electrical property of the same was investigated by studying the dielectric constant, and AC conductivity. There are fluctuations in these properties with variation in Zirconium substitution in Ni-Zn Ferrite.

Doped holographic superconductors in the Gubser–Rocha model

We construct a doped holographic superconductor in the Gubser–Rocha model, and realize a superconducting dome in the middle of the temperature-doping phase diagram. It is worth noting that unlike in previous research, the profile of our dome shrinks inward near to zero temperature. From the numerical observation for the coupling dependence of the phase diagram, we find that the coupling between the two gauge fields plays a crucial role in the formation of the dome. We also analytically calculate the DC conductivity of the normal phase of the system in the momentum dissipation and obtain resistivity which is proportional to the temperature. The AC conductivity is calculated numerically.

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 - 2MHz. 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 -parameter value being less than unity. The values of -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.

Investigation on structural, optical, thermal, and dielectric properties of cellulose propionate/styrene-maleic anhydride copolymer/molybdenum nanocomposite prepared by pulsed laser ablation

Polymer nanocomposite films of cellulose propionate/styrene-maleic anhydride copolymer/molybdenum (CP/SMAC/Mo) were fabricated by pulsed laser ablation of Mo in the polymer solution for 10, 20, and 30 min. The films were then characterized by various analytical methods. X-ray diffraction (XRD) revealed that the addition of Mo to CP/SMAC removed the crystalline peaks of Mo without changing the amorphous nature of the copolymer. According to the scanning electron microscopy (SEM) and atomic force microscopy (AFM) patterns, Mo atoms were trapped in the amorphous polymer stacks. The energy-dispersive X-ray (EDX) spectrum features C, O, and Mo. FTIR confirmed the embedding of Mo in the polymers. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) were carried out on the samples. The pristine polymer film exhibited a band gap energy of 2.9 eV, which decreased to 2.05 eV because of the loading of the Mo nanoparticles. The intensity of the photoluminescence (PL) peak of the films increases with ablation time such that the absorption intensity of the film at a λmax of 426 nm increases by trifold during the 30 minutes of irradiation, which is consequently due to the increased amount of Mo in the nanostructure. The incorporation of Mo in the polymer matrix enhances the dielectric constant (ε') (6.28-18.13) and ac conductivity (σac) (3.19 × 10−5-1.12 × 10−4 S/cm) of the polymer with negligible dielectric loss. The results suggest possible technological utilization of these materials in such applications as supercapacitors, light-emitting diodes, and organic optoelectronic devices, among others.