Dc Conductivity Research Articles

Enhanced Efficiency of Silicon Solar Cell by New Salophen Complexes Embedded PMMA as Light Concentrators

The Schiff base N,N-bis(salicylidene)-o-phenylenediamine (salophen) was prepared by the condensation of salicylaldehyde with o-phenylenediamine in ethanol solution. Two new Zn(II) and Ni(II) salophen complexes, were synthesized, fully characterized by infrared (IR), 1H NMR spectroscopic measurements, UV–Vis spectra, photoluminescence (PL), and X-ray diffraction (XRD). The prepared complexes were used as phosphors to fabricate complexes/PMMA slab-based luminescent solar concentrators (LSC). The thermal stability of pure and doped PMMA polymer was examined by differential scanning calorimetry. Various parameters such as the optical energy gap, refractive index, AC and DC conductivity, dielectric constant, dielectric loss, Urbach energy, fluorescence quantum yield, and Stokes shift have been calculated and discussed. Optical absorption is carried out in wavelength region 200–900 nm at room temperature before and after the samples have been exposed to sunlight for up to 8 h. Photodegradation studies showed that the Zn(II) complex/PMMA LSC has the lowest rate of degradation compared with Ni(II) complex/PMMA LSC with the same concentration (0.06% weight). I–V characteristics of the photovoltaic devices with and without collectors were examined. The PV cell coupled with LSC shows an increase in maximum efficiency by about 50% compared to the normal one. This indicates that the proposed technique is very useful for improving the efficiency of solar cells.

Enhancing the Conductivity and Dielectric Characteristics of Bismuth Oxyiodide via Activated Carbon Doping.

Activated carbon/BiOI nanocomposites were successfully synthesized through a simplistic method. The produced composites were then characterized using XRD, TEM, SEM-EDX, and XPS. The results showed that BiOI with a tetragonal crystal structure had been formed. The interaction between activated carbon and BiOI was confirmed via all the mentioned tools. The obtained nanocomposites' electrical conductivity, dielectric properties, and Ac impedance were studied at 59 KHz-1.29 MHz. AC and dc conductivities were studied at temperatures between 303 and 573 K within the frequency range of 59 KHz-1.29 MHz. The 10% activated carbon/BiOI nanocomposite possessed dc and AC conductivity values of 5.56 × 10-4 and 2.86 × 10-4 Ω-1.cm-1, respectively, which were higher than BiOI and the other nanocomposites. Every sample exhibited increased electrical conductivity values as the temperature and frequency rose, suggesting that all samples had semiconducting behavior. The loss and dielectric constants (ε' and ε″) also dropped as the frequency increased, leading to higher dielectric loss. The Nyquist plot unraveled single semicircle arcs and a decreased bulk resistance, indicating decreased grain boundary resistance. Consequently, the electrical characteristics of BiOI, 1C/BiOI, 5C/BiOI, and 10C/BiOI implied their applicability as dielectric absorbers, charge-stored capacitors, and high-frequency microwave devices.

Nonlinear phenomena in charge transport properties of a hole-doped organic spin-liquid compound

The nonlinear electric conductivity of κ-(BEDT-TTF)4Hg2.89Br8, which is known as a hole-doped spin liquid, has been observed by single crystal transport measurements using dc and ac excitations. This compound is known as a charge transfer complex with strong magnetic fluctuations accompanied by electron mass enhancement at ambient pressure. We discuss the nonlinear dc conductivity drastically emerging below 100 K. We also performed ac impedance measurements of this compound and compared the results with those of a typical dimer-Mott compound of deuterated κ-(d8-BEDT-TTF)2Cu[N(CN)2]Br, located just near the Mott boundary. The analyses of the Nyquist plots of κ-(d8-BEDT-TTF)2Cu[N(CN)2]Br and κ-(BEDT-TTF)4Hg2.89Br8 reveal qualitatively different features. The former shows a behavior pertinent to the inhomogeneous distribution of domains due to a mixing of metal and insulating phases, taking into account the influence of the proximity effect, while the doped spin liquid has a distinct semicircle-type frequency dependence in its Nyquist plot in the whole temperature range studied. We conclude that the nonlinear conductivity is intrinsically peculiar to the doped dimer Mott system, where the charge degrees of freedom dominate the itinerancy. We attribute the anomalous features, such as non-Fermi liquid behavior, heat capacity enhancement, and strong antiferromagnetic fluctuations in κ-(BEDT-TTF)4Hg2.89Br8, to a kind of charge confinement effect retained in the hole-doped spin-liquid state.

Investigation on structural, optical, thermal, and dielectric properties of nanocomposite films based on chitosan containing vanadium pentoxide/zinc oxide and their potential for optoelectronics devices

Chitosan (Cs), zinc oxide (ZnO), and vanadium pentoxide (V2O5) nanoparticles (NPs) have been used to create ternary nanocomposite materials to improve their optical and electrical characterization. Physical methods have been used to investigate the effects of varying vanadium pentoxide nanoparticle contents on the optical and electrical characterization of the prepared films. In XRD results obtained, the characteristic peaks of pure chitosan are seen to be broken and vanished (especially at 15 wt.% V2O5 NPs). This means that when chitosan is filled with different concentrations of V2O5 nanoparticles, chitosan is very weak and simply broken, and only characteristic peaks of V2O5 appear. The average crystal size of V2O5 has been determined to be 25.4 nm. FTIR spectra approve the strong complexation between the nanoparticles and hydrogen bonds in the composite. The study suggests that the addition of zinc and vanadium nanoparticles to chitosan-based films can improve their thermal stability, which has potential applications in various industries, including packaging, biomedical, and environmental. Electrical studies indicate that as the content of embedded zinc/vanadium-filled-in chitosan rises, the ε′ value decreases. The observed decrease in the insulating behavior of chitosan aligns with the notion that doping reduces its insulating properties. This aligns with the enhanced electrical conductivity evident from the DC conductivity measurements. The study demonstrates that incorporating zinc oxide (ZnO) and vanadium pentoxide nanoparticles effectively influences the dielectric properties and relaxation behavior of chitosan. The given results suggest Ternary nano-composite chitosan-ZnO/V2O5 films for specific requirements in optical, optoelectronic applications.

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.

Correlation of thermal and electrical properties of silver germanophosphate glasses with their structural analysis by Raman and NMR spectroscopy

In present study glasses of the system Ag2O-GeO2-P2O5 were studied in the compositional series (50−x)Ag2O-xGeO2-50P2O5 with x = 0−40 mol%. Ag2O substitution by GeO2 results in a significant increase of both glass transition temperature, Tg, and crystallization temperature, Tc, up to 628 °C (Tg) and 851 °C (Tc) at x = 40 mol% GeO2. The glass structure was investigated from the analysis of 31P MAS NMR and Raman spectra. Both methods show transformation of phosphate glass network formed mainly by Q2 units to germanate-phosphate network formed by Q1xGe and Q21Ge phosphate units and germanate units. Raman spectra, in addition, reveal evolution of P‒O‒P linkages to P‒O‒Ge and Ge‒O‒Ge linkages through the glass series. DC conductivity trend upon GeO2 addition showed non-monotonic behaviour, which is related to structural changes in the glass-network.

Magnetoelectric Properties of Multiferroic Composites Based on BaTiO3 and Nickel-Zinc Ferrite Material.

The purpose of the present study was to learn the morphological, structural, ferroelectric, dielectric, electromechanical, magnetoelectric, and magnetic properties, and DC conductivity of BaTiO3-Ni0.64Zn0.36Fe2O4 (BT-F) multiferroic composites compacted via the free sintering method. The influence of the ferrite content in ceramic composite materials on the functional properties is investigated and discussed. X-ray diffraction studies confirmed the presence of two main phases of the composite, with strong reflections originating from BaTiO3 and weak peaks originating from nickel-zinc ferrite. BT-F ceramic composites have been shown to exhibit multiferroism at room temperature. All studied compositions have high permittivity values and low dielectric loss, while the ferroelectric properties of the BT component are maintained at a high level. On the other hand, magnetic properties depend on the amount of the ferrite phase and are the strongest for the composition with 15 wt.% of F (magnetization at RT is 4.12 emu/g). The magnetoelectric coupling between BT and F phases confirmed by the lock-in technique is the largest for 15 wt.% ferrite. In the present work, the process conditions of the free sintering method for obtaining BT-F multiferroic composite with good electrical and magnetic properties (in one material) were optimized. An improved set of multifunctional properties allows the expansion of the possibilities of using multiferroic composites in microelectronics.

Electrical/thermal conductivities of low-temperature sintered/Ag-decorated epoxy microspheres

The last decades composite production has benefited from additive manufacturing rendering production of special parts feasible and economical. Energy and time-consuming processes have improved significantly since the implementation of low temperature sintering methods. In this work, we prepare sub-micron powders in an attempt to produce conductive composites via compression sintering at a low overall production cost. Epoxy microspheres of glassy and rubbery type are synthesized in a controlled manner to inherit certain properties, and then decorated via a controlled deposition process of silver nanoparticles to form fine powders. The resulting fine powders are compressed at room temperature conditions to consolidate and hopefully sinter at post-cure. We study the structure-property relationship of the powder structure and the effect in the conductive properties that arise after consolidation. Remarkably, the compressed powders achieved DC conductivity with extremely low silver nanoparticle content (7.7 wt %, approx. 0.9 vol %) as compared with other literature reports and a promising increase in thermal diffusivity of about 18 % with just 4.2 wt % of silver nanoparticles.

Investigation of Dielectric Properties of Quaternary Ceramic 0.47BNT-0.04BT-0.37PMN-0.18PT

Dielectric dispersion analysis has been carried out for the first time on a new quaternary ceramic [0.47(Bi0.5Na0.5)TiO3-0.04BaTiO3-0.31Pb(Mg1/3Nb2/3)O3-0.18PbTiO3] having a morphotropic phase boundary composition. The measurement of the dielectric parameters has been carried out in the frequency range of 200 Hz to 2 MHz and temperature range from 30 oC to 300 oC. The material showed high dielectric constant, low dielectric loss, negligible DC conductivity and high ferroelectric to paraelectric transition temperature. A clear Debye type relaxation was observed in the dielectric constant and dielectric loss data. An interesting feature of two Debye peaks has been noticed in dielectric loss versus frequency curves in the temperature range 125 oC to 175 oC. These peaks shift towards higher frequencies when temperature is increased. The extracted relaxation times of the two peaks are three orders of magnitude different and have been found to follow the Arrhenius law with significantly different activation energies.

Effect of NASCION‐Type ceramic dispersion in PAN/PVA‐based blend polymer electrolyte: A structural, thermal, and electrical study

AbstractSolid flexible separators having adequate ion conductivity at ambient temperature along with good thermal and voltage stability are potential candidates for separators in all solid‐state ion batteries. In the present work, zirconium and niobium‐doped Li1.3Al0.3Ti1.7 (PO4)3 ceramic particles have been incorporated into a polyvinyl alcohol (PVA) and polyacrylonitrile (PAN)‐based blend that served as a flexible matrix to create a flexible polymer–ceramic framework and have been examined for conductivity, dielectric properties, voltage stability, thermal stability, and electrochemical performance. The flexible polymer–ceramic framework shows high thermal stability, improved conductivity, and a high‐voltage window. Optimized dc conductivity of 9.8 × 10−5 S cm−1 has been observed among all investigated samples, with an improved voltage stability of 4.94 V. Further, the Trukhan model has been used to understand the effect of filler loading on ion migration properties. The optimized solid polymer electrolyte (SPE) shows improved ion mobility (μ) of 5.13 × 10−2 cm2 V−1 s, number density (n) = 2.39 × 1015 cm3, and diffusion coefficient (D) of 2.09 × 10−3 cm2 s−1. It also shows a very high specific capacitance of ~10−4 Fg−1, excellent cycling stability, and 93.75% capacity retention after 100 cycles.

Generalized extremal branes in AdS/CMT and holographic superconductors

AdS4 generalized extremal branes are scrutinized in the context of AdS/CFT. Holographic superconductors are studied as dual objects to AdS4 generalized extremal branes, whose coefficients of response and transport in the dual condensed matter theory are calculated and discussed. The holographic Weyl anomaly is also addressed. The holographic superconductor bound current is shown to be enhanced by the parameter controlling the family of AdS4 generalized extremal branes, when compared to the standard AdS4-Reissner–Nordström black brane results. In the probe limit, the electrical DC conductivity for holographic superconductors with AdS4 generalized extremal branedual background is also reported.

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.

Contribution of strong electron-phonon interaction in the transport properties of La0.8Ca0.2Mn0.5Ni0.5O3 system

La0.8Ca0.2Mn0.5Ni0.5O3 NTC (negative thermal coefficient) thermo-sensitive material was prepared using a conventional solid-state reaction method. From the structural results, we found that the material is pure and crystallizes in the orthorhombic structure with a Pnma space group. It is found that the La0.8Ca0.2Mn0.5Ni0.5O3 ceramic can be used as an NTC thermistor compound in specific temperature sensors and attenuators. Based on Holsten's theory, detailed electrical investigations concerning the nature of the activated small polaron hopping mechanism were reported. The temperature dependence of the DC conductance was used to determine the electrical conduction processes that govern the transport properties of La0.8Ca0.2Mn0.5Ni0.5O3. Hence, the DC mechanisms exhibit changes from the variable range hopping at very low temperatures to the non-adiabatic small polaronic hopping at T = 210 K. In the intermediate temperature range, the semiconductor behavior of La0.8Ca0.2Mn0.5Ni0.5O3 was attributed to the contribution of the tunneling transport process. At various temperatures, the conductance spectra were discussed based on Jonscher and Bruce's laws. Contributions of the overlapping-large-polaron-tunneling, the correlated barrier hopping, the quantum mechanical tunneling, and the non-overlapping small polaron tunneling mechanisms to the transport properties were observed in the dispersive region of the conductance spectra. In addition, Summerfield scaling and corrected Summerfield scaling approaches prove that the charge mobility is temperature-dependent. The positive value of the correction parameter α = 1.2 confirms the presence of interactions in the studied sample.

How to fail the measure of DC conductivity or resistivity of polymeric materials

How to fail the measure of DC conductivity or resistivity of polymeric materials

Mixed conduction in iodovanadate glass-nanocomposites: DC conductivity, hopping frequency, and frequency response curves

Mixed conduction in iodovanadate glass-nanocomposites: DC conductivity, hopping frequency, and frequency response curves

Ionic Conductivity of a Lithium-Doped Deep Eutectic Solvent: Glass Formation and Rotation-Translation Coupling.

Deep eutectic solvents with admixed lithium salts are considered as electrolytes in electrochemical devices, such as batteries or supercapacitors. Compared to eutectic mixtures of hydrogen-bond donors and lithium salts, their raw-material costs are significantly lower. Not much is known about glassy freezing and rotational-translation coupling of such systems. Here, we investigate these phenomena by applying dielectric spectroscopy to the widely studied deep eutectic solvent glyceline, to which 1 and 5 mol % LiCl were added. Our study covers a wide temperature range, including a deeply supercooled state. The temperature dependences of the detected dipolar reorientation dynamics and ionic direct current (dc) conductivity reveal the signatures of glassy freezing. In comparison to pure glyceline, the lithium admixture leads to a reduction of ionic conductivity, which is accompanied by a reduction of the rotational dipolar mobility. However, this reduction is much smaller than that for deep eutectic solvents (DESs), where one main component is lithium salt, which we trace back to the lower glass-transition temperatures of lithium-doped DESs. In contrast to pure glyceline, the ionic and dipolar dynamics become increasingly decoupled at low temperatures and obey a fractional Debye-Stokes-Einstein relation, as previously found in other glass-forming liquids. The obtained results demonstrate the relevance of decoupling effects and glass transition to the enhancement of the technically relevant ionic conductivity in such lithium-doped DESs.

Electronic and optical properties of Na2O doped P2O5-TeO2− CoO-ZnO glasses

The phospho-tellurite glasses, (P2O5)0.25-(TeO2)0.5-x-(CoO)0.1-(ZnO)0.15-(Na2O)x ; x = 0.15, 0.20, 0.25, 0.30 and 0.35 were prepared by melt quenching and their non-crystalline nature confirmed through XRD. Density is found decreased and molar volume increased with increase of Na2O concentration and they behaved opposite to each other. The physical parameters such as transition metal ion density, mean distance between TMIs, small polaron radius, oxygen packing density and field strength were estimated. DC conductivity was measured by following two probe method in the temperature range 303K – 633K. High temperature conductivity is explained by Mott’s small polaron hopping (SPH) model and low temperature conductivity by Mott’s VRH model. Both conductivity and activation energy are found to be increasing with Na2O content. Density of states at Fermi level are found to be of the order of 1021 to 1024 eV−1 cm−3. UV-Vis spectra were recorded for the wavelength range 200-800 nm. Optical band gap (direct and indirect) except for x=0.20 is found increased, urbach energy and refractive indexes are found decreased with Na2O concentration. Various optical parameters such as molar polarizibility, metallization criterion, reflection loss, electronic polarizability, optical transmission coefficient, dielectric constant and optical dielectric constant have been determined.

Biological and physical studies on the protective and therapeutic roles of ashwagandha seed extract against the potential toxic effect of amoxicillin in rats

Background Ashwagandha plant enhances the body’s defense against toxicants through improving the cell-mediated immunity. Objective The present work was performed to assess the protective and therapeutic efficiencies of ashwagandha seed extract (ASE) against the harmful effects of amoxicillin (AM) treatment on biological and physical parameters in the brain, liver, and testes tissues of rats. Materials and methods Total RNA was isolated from brain, liver, and testes tissues to assess the gene expression of steroid 5 alpha-reductase 1 (5α-R1), multidrug resistant 1b (mdr1b), and luteinizing hormone receptor (LHR) genes, respectively. The cDNA was synthesized and real-time polymerase chain reaction (Real-time PCR) was performed, total antioxidant capacity (TAC) was measured. Histological examination and physiological tests for the cerebral cortex of brain tissue were recorded. Results and conclusion Our findings revealed that AM treatment (90 mg/kg. b.wt.) caused detrimental effects in all biological parameters, including up-regulation of gene expressions and reduction of TAC values in brain, liver, and testes tissues, in addition to severe damage to histological architectures in the cerebral cortex, including hemorrhage and neurodegeneration. ASE treatment at different doses (100, 200, and 300 mg/kg) significantly enhanced the biological and physical parameters. As the ASE dose level increased, it was observed that these improvements in gene expressions and TAC also increased. Gene expression enhancements were more pronounced in the therapeutic efficacy of ASE, whereas TAC enhancements were more pronounced in the protective efficacy of this medicinal plant extract, particularly in brain and liver tissues. In terms of histopathological parameters, the damage caused by AM was reduced by using 300 mg/kg of protective ASE than 200 mg/kg of therapeutic ASE. Biophysical investigation indicated that relaxation time and enthalpy were restored and improved, while DC conductivity was not recovered by ASE use against AM damages. The present investigation provided biological and physical evidence for protective and therapeutic efficiencies of ASE against lesion effects of AM in the previously mentioned tissues of rats.

Enhanced electrical properties of polypropylene insulation based on β‐nucleated crystallization regulation for high‐voltage direct current cable

AbstractThis study investigates the effect of crystallisation regulation on the electrical properties of β‐modified polypropylene (PP) insulation. Various β‐modified polypropylene insulation samples are prepared by controlling the melting temperature within the range of 180°C–200°C, and the ensuing crystallization characteristics of polypropylene insulation are evaluated. It is observed that the crystallinity decreased with increase in melting temperature, while the β crystal fraction and the lamellae long period increased. Notably, PP insulation subjected to a melting temperature of 200 °C demonstrates a substantial 47.1% decrease in DC conductivity, accompanied by a notable 22.6% reduction in space charge accumulation, concomitant with a significant 14.6% enhancement in DC breakdown strength. Additionally, a higher β crystal fraction in PP insulation is found to correspond to an increased density of deep traps, notably at an energy level of 0.95 eV. The elevated melting temperature effectively eradicates the melting memory effect, thereby facilitating the induction of β crystals by the β‐nucleating agents. The parallel lamellae structure inherent in β crystals serves to diminish interface defects between spherulites, consequently mitigating carrier mobility, curtailing space charge accumulation and enhancing breakdown strength.

Research on Joint Sensing Technology for Vibration and Dielectric Spectrum of Power Equipment in the Context of New Power Systems

Abstract This paper has carried out the test results of SF6 gas decomposition products and the dielectric spectrum detection, proposed method for the identifying equipment defects based on decomposition products, and the partial discharge detection and diagnosis method for the equipment discharge defects. Combining the above two methods, the GIS discharge defects are comprehensively evaluated by decomposition products and partial discharge detection, achieving the type prediction of latent faults in operating switch-gear. In the aspect of vibration signal analysis, this paper conducts the wavelet analysis of the vibration signals and obtains frequency spectrum results under multi-layer wavelet decomposition. In the aspect of dielectric spectrum analysis, a model of three HN function superposition was used to fit the experimental data to verify the validity of the model, and the characteristic parameters such as the DC conductivity were extracted. It was found their dependence on temperature basically conformed to the Arrhenius formula. On this basis, the thermal aging test platform for the epoxy resin samples was established, and an accelerated thermal aging experiment was conducted at the temperature of 115 °C. The dielectric response test system was used to measure dielectric spectra of the samples with different aging times, compare the dielectric spectra at different aging times, and analyze the reasons for the differences.