Enhancement Of Electrical Properties Research Articles

Structural, optical and electrical characterizations of ZnO/PS

This work reported on solar cell ZnO/PS heterojunction fabricated from Zinc nitrate with molar concentrations 0.05M and 0.2M using spray pyrolysis technique, to study the effect of high and low molar concentration of Zn precursor on structural, optical and electrical properties. The structural analyse showed that the obtained thin films deposited on glass substrate were polycrystalline with a hexagonal wurtzite structure and preferentially oriented along the c-axis direction, while structural properties enhanced with higher morality 0.2M. Roughness surface of ZnO/PS HJ increased widely with higher morality. Through I-V characteristics, the enhancement of electrical properties with higher molarity has been achieved. Isc get augment from 23mA/cm2, to 27mA/cm2, and Voc from 551mV to 554mV when molarity has taken values 0.05M and 0.2M respectively. Ideality factor has influenced by molarity variance too. The impact of solar irradiance G and temperature T on solar cell fabricated from 0.2M molarity has been investigated. The current density increased from 13.53 mA/cm2 to 27mA/cm2, the voltage from 525mV to 546mV, and the efficiency from 5.2% to 10.9% when the solar irradiance have increased from 500 to 1000W/m2. The temperature also influences on the solar cell behaviours, especially the voltage is enhanced by temperature increasing.

Large enhancement of electrical transport properties of SnS in the out-of-plane direction by n-type doping: a combined ARPES and DFT study

The resonant states induced by pnictogen dopants and a more delocalized charge density suggest a potential improvement of the thermoelectric performance of SnS.

Efficient Polymer Scattering Layers Fabrication and their Applications in Electrical Properties Enhancement of Perovskite/SiliconTandem Solar Cells

Efficient Polymer Scattering Layers Fabrication and their Applications in Electrical Properties Enhancement of Perovskite/SiliconTandem Solar Cells

Development of a flexible and conductive elastomeric composite based on chloroprene rubber

Flexible and conductive nanocomposites with enhanced mechanical and dielectric properties have been fabricated from reduced graphene oxide (RGO) reinforced polychloroprene rubber (CR). Composites were prepared on a two-roll mixing mill and the morphological analysis using SEM and TEM showed good dispersibility and exfoliation of RGO layers in the matrix. It imparted a critical role in the enhancement of mechanical and electrical properties of the composites. Composites with 0.9 phr of RGO showed an enhancement in tensile strength, tensile modulus and electrical conductivity as 92%, 75%, and 103% respectively more than the pristine polychloroprene. RGO formed a good conducting percolating network in the polychloroprene matrix and it led to the formation of a dielectric composite material with enhanced electrical properties.

Enhancement of electrical properties of flexible ITO/PET by atmospheric pressure roll-to-roll plasma

Flexible materials can significantly reduce the cost of the electronic devices because they can be manufactured by large-area roll-to-roll (R2R) processing. In this work, R2R atmospheric pressure plasma was used to modify flexible indium-tin-oxide films on polyethylene terephthalate foil (ITO/PET). Plasma treatment was performed in different feed gases consisting of various ratio between nitrogen and oxygen. A range of experimental techniques were used to study surface properties of ITO/PET, including X-ray and Ultraviolet photoelectron spectroscopies, four-point probe, Atomic force microscopy and UV–Vis measurement. We found that R2R plasma treatment decreased carbon contamination and increased the number of oxygen vacancies on the surface, whereas the ratio between indium and tin remained constant. UPS showed an increase in the work function from 3.9eV for untreated sample to 5.1eV for sample treated in plasma for very short time of 2s. Four-point probe measurement demonstrated remarkable decrease in sheet resistance from 44.2Ω/sq to 11.7Ω/sq after plasma treatment for 2s. The AFM and UV–Vis measurements revealed only slightly change on the surface morphology and transmittance of the ITO/PET. The plasma treated foils were stored under laboratory environment and inside of the glovebox to study the effect of the environmental conditions on the stability of the improved properties. The ITO surfaces stored in laboratory environment for 3 weeks preserved approx. 60% of the properties achieved by plasma treatment, e.g. work function of the samples was approx. 4.5eV after 3 weeks (and 5 weeks) ageing time in the laboratory environment.

Homogenous Dispersion of MoS2 Nanosheets in Polyindole Matrix at Air-Water Interface Assisted by Langmuir Technique.

Two-dimensional (2D) inorganic layered materials when embedded in organic polymer matrix exhibit exotic properties that are grabbing contemporary attention for various applications. Here, nanosheet morphology of molybdenum disufide (MoS2) synthesized via one-pot facile hydrothermal reaction are exfoliated in benign aqueous medium in the presence of indole to obtain a stable dispersion. These exfoliated nanosheets then act as host to template the controlled polymerization of indole. The preassembled MoS2-polyindole (MoS2-PIn) nanostructures are reorganized at the air-water interface using the Langmuir method to facilitate maximum interfacial interaction between nanosheet and polymer. This report emphasizes large area, homogeneous dispersion of uniform-sized MoS2 nanosheets (40-60 nm diameter) in the PIn matrix and the formation of stable and uniform film via the Langmuir-Schaefer (LS) method. These self-assembled, MoS2 decorated PIn LS films are characterized using atomic force microscopy (AFM) and transmission electron microscopy (TEM). The fabricated LS films in sandwiched structure Al/MoS2-PIn/ITO as the Schottky diode portrayed remarkable enhancements in charge transport properties. Our study illustrates the potential of the MoS2-PIn LS film in electronic applications and opens a new dimension for uniform dispersion of 2D materials in other polymers via the Langmuir method for device fabrication and enhancement of electrical properties.

Enhancement of piezoelectric and ferroelectric performances in (Na0.85K0.15)0.5Bi0.5TiO3 films with BaTiO3 interlayers

In this work, in order to optimize the electrical performance of (Na0.85K0.15)0.5Bi0.5TiO3 (NKBT) thin films, 20 nm-thick BaTiO3 (BTO) layer was utilized by deliberately coating in the NKBT film-substrate interface or in the NKBT film, i.e., BTO layers coated in sequence with NBKT layers. The BTO layer, especial coated in the NKBT film, was beneficial for crystallization process and more preferable to form a denser film morphology. The BTO-coated NKBT composite films exhibited much enhancement in electrical properties compared to the films without BTO layer. Accordingly, a high effective piezoelectric coefficient d33* of 75pm/V and remnant polarization Pr of 22.1μC/cm2, as well as a low leakage current density of 1.2×10−5A/cm2 were obtained in the 460 nm-thick composite film with BTO layers coated in the NBKT film. It meant that this kind of BTO-coated NKBT composite film could perform as a potential candidate for the lead-free piezoelectric applications. The observed enhancement in the electrical properties with the introduction of BTO layer could be mainly explained by the weakened influence of domain pinning in the film-electrode interface and grain boundaries due to the decreased strain in the film-electrode interface and better crystallinity in the highly (110)-oriented NKBT films, thereby enhancing motion of domain-walls.

Enhancement in electrical and optical properties by substitution of lanthanides (Nd3+ and Eu3+) in lead free Na0.5Bi0.5 TiO3 ceramics

ABSTRACTThe eco-friendly Na0.5Bi0.5TiO3 (NBT) and its derivatives have been synthesized by conventional solid state route. According to Judd-Ofelt theory, the higher symmetry phase suppresses the electrical and optical properties. Here, the ferroelectric and photoluminescence (PL) properties are influenced by the crystal structure symmetry. In the present work, these properties are optimized with minimal substitution of Nd and Eu at Bi-site in the NBT for introducing PL as an extra functionality without compromising ferroelectric properties. The evolution of photoluminescence in the visible and infrared region has been observed which may be useful in the field of piezochromic based devices.

Electrical and mechanical properties of Nitrile rubber (NR) filled with industrial waste and by product from manufacture of ferrosilicon alloys in Egyptian chemical industries company

This work focused on using silica fume (by product) and quartz (industrial waste) in manufacture of ferrosilicon alloys in Egyptian chemical industries company (KIMA), in Aswan, Egypt. To reinforce the properties of Nitrile rubber, reduce cost and save the environment from industrial waste. Preparation rubber composites by addition different concentrations from silica fume filler (byproduct) and quartz filler (industrial waste). Investigation on the insulation properties of nitrile rubber composites by measurement of flashover voltage for unfilled nitrile rubber (blank) and nitrile rubber composites with silica fume filler and quartz filler. The measurement of flashover voltage for nitrile rubber composites occurred in different conditions (dry, wet, salinity and acidity). The effect of silica fume filler and quartz filler on mechanical properties of nitrile rubber was studied by investigation on elongation at break for nitrile rubber composites and also tensile strength. Studied the effect of hybrid filler on enhancement of electrical properties and mechanical properties of nitrile rubber, by addition different concentrations of mica filler on the samples showed the least enhancement in insulation properties of nitrile rubber composites in case of silica fume and quartz filler. And also study the morphology of nitrile rubber composites. http://ejchem.journals.ekb.eg/article_3828.html

Electrical property enhancement by controlled percolation structure of carbon black in polymer-based nanocomposites via nanosecond pulsed electric field

The research group of this study demonstrates how Nanosecond Pulsed Electric Field can be used to tune the localization and formation of conducting carbon black (CB) assembles into linear structures with various thicknesses inside an insulating polymer matrix. The Electrorheology phenomenon of CB assembles in pre-polymer of polysiloxane under application of either DC or nanosecond pulsed electric field was observed utilizing optical microscopy method. Comparing to the typical DC electric field which has a value of 1875 V/mm, the nanosecond pulsed electric field facilities the increase in its electric field strength; generated between two constructed electrodes with a space size of 160 μm, to a value reaching 7500 V/mm. This type of electric field can overcome the voltage breakdown that occurs within the tested materials. The conduction structure of CB forms linear assemblies that anchor the composite film surfaces inside the matrix, which could be developed to much thicker percolation structures over five times by the application control of the nanosecond pulsed electric fields. Furthermore, the formation of vertically upright electrical percolation structures attributed to the remarkable decrease of the electrical resistivity of the resulting composites to 3 order of magnitude compared to the composites with a uniform distribution of filler. The electrorheology phenomenon under pulsed field was also tested by the optical observation method. The thickness as well as the concentration of CB particles were able to be controlled via the increasing in the nanosecond pulsed electric field. The novelty of this study lies in the utilizing of nanosecond pulsed field with a high electric strength that overcomes the electrical breakdown during tuning the carbonaceous filler assemblies. This unique technology is energy saving through fabricating polymer-based conductive materials without using surface modification or increasing the filler content.

Enhancement of mechanical and electrical properties of continuous-fiber-reinforced epoxy composites with stacked graphene.

Impregnation of expandable graphite (EG) after thermal treatment with an epoxy resin containing surface-active agents (SAAs) enhanced the intercalation of epoxy monomer between EG layers and led to further exfoliation of the graphite, resulting in stacks of few graphene layers, so-called “stacked” graphene (SG). This process enabled electrical conductivity of cured epoxy/SG composites at lower percolation thresholds, and improved thermo-mechanical properties were measured with either Kevlar, carbon or glass-fiber-reinforced composites. Several compositions with SAA-modified SG led to higher dynamic moduli especially at high temperatures, reflecting the better wetting ability of the modified nanoparticles. The hydrophilic/hydrophobic nature of the SAA dictates the surface energy balance. More hydrophilic SAAs promoted localization of the SG at the Kevlar/epoxy interface, and morphology seems to be driven by thermodynamics, rather than the kinetic effect of viscosity. This effect was less obvious with carbon or glass fibers, due to the lower surface energy of the carbon fibers or some incompatibility with the glass-fiber sizing. Proper choice of the surfactant and fine-tuning of the crosslink density at the interphase may provide further enhancements in thermo-mechanical behavior.

Efficiently two-stage synthesis and characterization of CuSe/Polypyrrole composite thin films

A novel CuSe/PPy composite thin film was fabricated easily via electrodeposition method on ITO substrate in two stages. In order to determine deposition potentials, the electrochemical response of Cu and Se elements, and monomer were analyzed by cyclic voltammetry, and then chronoamperometry technique was used to synthesis of the conductive metal/polymer chalcogenide films. The morphology, electrical and optical properties of the films are presented in detail. SEM studies indicate that the Cu and Se nanoparticles are uniformly coated on ITO surface together with PPy. EDX analyses show that Cu and Se components are successfully electrodeposited into PPy polymer matrix. FTIR studies also confirm that PPy is synthesized and the CuSe nanoparticles are successfully loaded into PPy. The optical energy band gap (Eg) of the PPy thin films decreases from 1.78 to 1.44 eV with the addition of CuSe nanoparticles. Hall-effect measurements reveal that both films exhibit semiconducting behavior, and the addition of CuSe into the PPy matrix plays an important role in the enhancement of electrical properties. The results show that the produced CuSe/PPy nanocomposite film can be considered a promising material for solar cell applications and the two stage synthesis method used for this composite film may be applied to other metal/polymer chalcogenides due to the low-cost, large-scale and easy fabrication.

Improving crystallization and electron mobility of indium tin oxide by carbon dioxide and hydrogen dual-step plasma treatment

Obtaining high conductivity indium tin oxide (ITO) films simultaneously with a “soft-deposited” (low temperature, low ions bombardment) and cost-efficient deposition process are critical aspect for versatile photo-electronic devices application. Usually, the low-cost “soft-deposited” process could be achieved via evaporation technique, but with scarifying the conductivity of the films. Here, we show a CO2 and H2 two-step plasma (TSP) post-treatment applied to ITO films prepared by reactive thermal evaporation (RTE), allows to meet the special trade-off between the deposition techniques and the electrical properties. Upon treatment, an increase in electron concentration and electron mobility is observed, which subsequently resulting a low sheet resistivity. The mobility reaches high values of 80.9cm2/Vs for the TSP treated ∼100nm thickness samples. From a combination of X-ray photoelectron spectroscopy and opto-electronic measurements, it demonstrated that: during the TSP process, the first-step CO2 plasma treatment could promote the crystallinity of the RTE ITO films. While the electron traps density at grain boundaries of polycrystalline RTE ITO films could be passivated by hydrogen atom during the second-step H2 plasma treatment. These results inspired that the TSP treatment process has significant application prospects owing to the outstanding electrical properties enhancement for “soft-deposited” RTE ITO films.

Revealing the role of heat treatment in enhancement of electrical properties of lead-free piezoelectric ceramics

The structural and electrical properties of the virgin, annealed, and quenched samples of 0.80BiFeO3–0.20BaTiO3 lead-free ceramics were investigated. The crystal structures investigated with the structure refinement method exhibited a rhombohedral structure for all the samples. The significant enhancement of ferroelectric and piezoelectric properties is ascribed to the relaxation of the lattice strain induced in the samples after the heat treatment. The bond-length calculated from the final structure refinement results revealed the increment of the A-O bond-length after the heat treatment, while the B-O bond-length was maintained in all the virgin, annealed, and quenched samples suggesting the specific influence of the lattice strain at the A-site of the material system.

Enhancement of structural and electrical properties of novelty nanoferrite materials

Novelty Cu–Cr nanoferrite, with the general formula CuCr0.3R0.03Fe1.67O4 (where R = Sm, Nd, Ce and La), were prepared by standard ceramic method and characterized by X-ray diffraction (XRD) analysis. Field emission scanning electron microscope (FESEM) and Energy dispersive X-ray analysis (EDX) were obtained for all samples. The effect of doping Cu–Cr ferrite with different rare earth (R3+) types on the structural and electrical properties showed that the ionic radius, electronic configuration and ionization potential for different R3+ could explain the results. Introducing R3+ in Cu–Cr ferrite retained parent cubic spinel structure ferrite. All R3+ types induced cation redistribution. At low temperature the ionic radius of R3+ control the conduction, whereas at high temperature the ionization potential have the decisive effect. It was found that La-doped Cu Cr sample had the lowest AC conductivity due to its large ionic radius and high ionization potential promising application in memories and microelectronics.

Electrical and structural properties enhancement in plasticized high Tg polymers using metal salts

ABSTRACTPlasticized polymer electrolyte composite has been prepared in the form of a film by solution casting method. Poly (ethyl methacrylate) (PEMA) acts as a host polymer and is doped with Sodium Iodide (NaI). Ethylene carbonate (EC) added as a plasticizer and also enhances amorphicity of the polymer electrolyte. The electrical conductivity of the PEMA+NaI was evaluated using complex impedance spectroscopy. Maximum ionic conductivity obtained at room temperature was 8.75 × 10−6 S/cm with the composition of PEMA: NaI (30%) + 60% EC. The conductivity further increased with increase in temperature and moved up to 5.8 × 10−5 S/cm. Scanning electron microscopy was used to study the surface morphology of the composite film. Fourier transform infrared ray and X-ray diffraction data confirmed the complexation of material.

Bioinspired graphene-based nanocomposites and their application in electronic devices

The increasingly popular flexible electronic devices, such as electronic papers, touch screens, roll-up displays, and wearable sensors, etc., require maintaining high performance, including mechanical and electrical properties, under repeatable deformation state. Graphene, as a two dimensional (2D) carbon nanomaterial with integrated high mechanical properties and electrical conductivity, could serve as the ideal building block for constructing functional materials in application of flexible electronic devices. There have been several attempts to use graphene-based nanocomposites in these devices. However, their assembly using traditional approaches, exhibit relatively poor mechanical and electrical properties, which largely limits the efficiency of these devices. Thus, it remains a great challenge to assemble microscopic graphene nanosheets into macroscopic high performance graphene-based nanocomposites. As known, the performance usually depends on the unique structure of materials, especially for the nanocomposites. Thus, it will be the next hot-topic that how to achieve the high performance flexible electronic device through designing and constructing the unique structures of graphene-based nanocomposites. Nacre, the “gold standard” for biomimicry with both high strength and toughness, has been the source of inspiration for designing many synthetic hybrid materials and nanocomposites. This is achieved through a precise architecture that resembles that of a brick wall, and the clever design of the interface. Compared to other approaches for constructing graphene-based nanocomposites, this bioinspired concept results in good dispersion, high loading and excellent interfacial interaction design. The resultant bioinspired graphene-based nanocomposites (BGBNs) demonstrate significant enhancement in mechanical and electrical properties. In this review, we summerize recent research progress on the BGBNs, following the research philosophy of discovery, invention, creation. Firstly, we analyze in detail the sophisticated interfacial architecture of natural nacre, which is responsible for its unique integration of high strength and toughness. Subsequently, we discuss the excellent mechanical and elertrical properties of graphene nanosheets. Then, we analyze and compare the effect of different interfacical interactions on the mecahnical and electrical properties of BGBNs. Furthermore, we discuss the synergistic effect from different interfacial interactions and building blocks for the fabrication of integrated strong and tough BGBNs. We highlight the fundamental physical properties of BGBNs, such as strength, toughness, and electrical conductivity. Specially, some other functions, including fatigue resistance, fire-retardant properties, etc., are also discussed. In addition, we also summarize the applications of BGBNs in flexible electronic devices, and discuss their challenges. Finally, we offer a perspective on the roadmap and target for BGBNs in the next 5−10 year as follows: (1) The essence of synergistic effect through different interfacial interactions and building blocks should be demonstrated and revealed by further theoretical simulation. (2) The tensile strength and stiffness of BGBNs can reach up to that comparable to carbon fiber reinforced composites, realizing application of BGBNs as structural materials in aerospace and aeronautics. (3) The integrated electrical and fatigue resistant properties should be simultaneously enhanced to satisfy the needs of flexible and wearable electronic devices. (4) Some simple, easy operation techniques will be explored for scaling up the fabrication of BGBNs, which could provide amount of BGBNs for practical applications in many fields.

Enhancement of electric and magnetic properties by tuning Co cluster in ZnO films via high magnetic field

To reveal the origin of magnetic coupling in dilute magnetic semiconductors (DMSs), this article utilized high magnetic field (HMF) in the process of oxidizing Co/Zn bilayers to study the influence of Co clusters and oxygen vacancy (Vo) content control on magnetic and electrical properties of Co doped ZnO (Co-ZnO) films. Results indicated that HMF can suppress the diffusion of Co and remain the content of Co clusters compared with oxidation growth in the absence of HMF. Moreover, HMF promoted the oxidation of Zn, improved the crystallinity in the films, and lowered the content of Vo. Consequently, the resistivity of the films oxidized in HMF was decreased by 50%, while both the saturation magnetization and coercivity were increased by 100%. This indicates that contribution of more Co clusters to the magnetic properties of the films is greater than that of Vo.

Enhancement in electrical and magnetic properties with Ti-doping in Bi0.5La0.5Fe0.5Mn0.5O3

In this investigation, we have synthesized Bi0.5La0.5Fe0.5Mn0.5-xTixO3 (where x = 0 and 0.05) samples. The Rietveld refinement of X-ray diffraction (XRD) patterns shows that the systems crystallize in the orthorhombic phase with the Pnma space group. The observed Raman modes support the XRD results. The appearance of prominent A1-3 and weak E-2 modes in Bi0.5La0.5Fe0.5Mn0.45Ti0.05O3 indicates the presence of chemically more active Bi-O covalent bonds. Ferromagnetism of Bi0.5La0.5Fe0.5Mn0.5O3 is enhanced by Ti doping at the Mn-site, indicating that these particular samples might be interesting for device applications.

Enhancement of dielectric and electrical properties in BFN/Ni/PVDF three-phase composites

To develop dielectric materials with high dielectric constant and low dielectric loss, a novel three-phase composite was prepared by embedding the nano-sized Ba(Fe0.5Nb0.5)O3 (BFN) crystallites and Ni crystallites into poly(vinylidene fluoride) (PVDF) matrix. The structure, dielectric and electrical properties of the composites were investigated. The superiority of this method is that, when compared with the two-phase Ni/PVDF composites, three-phase composites not only show significantly increased dielectric constants but also have lower dielectric loss. Our results show that a high dielectric constant of 475 and a relatively low loss of 0.61 were achieved at 100 Hz with 25 vol.% Ni and 50 vol.% BFN, respectively. The enhancement of dielectric constant of polymer based composites can be interpreted by the mini-capacitor principle and the interfacial polarization. The relatively low dielectric loss could be attributed to the isolation effect of BFN fillers. These composites with high dielectric constant and low dielectric loss are found to be potentially useful for embedded capacitor applications.