Papers by Keyword: Conductivity

Abstract: This research uses the Solid State method to produce LiNi_xFe_1-xPO₄ /C Composite Materials with variation Ni ion doping are x= 0.01, 0.02, and 0.03, Characterization was carried out using XRD, PSA, SEM and EIS. The results of XRD analysis showed that LiFePO₄, Li₃Fe₂PO₄ and Fe₂O₃ phases were formed. The conductivity test results show that the conductivity of the LFP/C precursor is 10.24x10^-4 S/cm, the LiNi_0.01Fe_0.99PO₄/C precursor is 7.75 x10^-4 S/cm, the LiNi_0.02Fe_0.98PO₄/C precursor is 10.334 x10^-4 S/cm, and the precursor LiNi_0.03Fe_0.97PO₄/C was 4.87 x10^-4 S/cm . With the highest conductivity value at LiNi_0.02Fe_0.98PO₄/C precursor.

Abstract: Among the numerous metal oxide semiconductors, zinc oxide (ZnO) is one of the most widely used materials in various fields due to its non-toxic nature, tunable electric and optical properties, and good thermal and chemical stability. This research aims to study the tuning of optical, electrical, and surface properties of ZnO film treated with dielectric barrier discharge (DBD) plasma produced at atmospheric pressure. The result revealed a significant decrease in its optical band gap, but there was an increase in conductivity. The results of contact angle measurement clearly showed the change of surface nature from hydrophobic to hydrophilic for DBD-treated ZnO film.

Abstract: Electrical conductive composite materials are nowadays widely used in many industrial applications include building materials. One of the possible applications is as a resistance probe. Those probes were designed to monitor internal structural changes of building materials built into construction and to predict their durability, over-load, or defects. Mostly used composite materials are silicate or biopolymer-based with carbon-based filler. This article is dedicated to the study of the microstructure of silicate-based electrically conductive composites with graphite-based fillers. The microstructural shape of fillers was chosen concerning preserving as high conductivity as possible. Furthermore, the effect of moisture on the electrically conductive properties of the silicate composite was monitored.

Abstract: In this study, polyaniline (PANI) was synthesized through oxidative polymerization assisted by sodium dodecylbenzene sulfonate (SDBS) in hydrochloric acid (HCl) concentration solution to investigate the effect of dopants in the electrical conductivity of polyaniline. The polyaniline obtained from the oxidative polymerization was confirmed with FTIR. The x-ray diffraction pattern showed that polyaniline is semi-crystalline. SDBS does not only act as a template for oxidative polymerization but also acts as a dopant. The dielectric constant, the dielectric loss, and the ac conductivity increase as polyaniline is doped with SDBS, HCl, or with both SDBS and HCl.

Abstract: We investigate the characteristics of polycrystalline Silicon (poly-Si) thin films for solar cells produced by very high frequency (VHF) plasma enhanced chemical vapor deposition using a conductive scanning probe microscope (SPM). We measure the surface morphology and local current images are simultaneously of the poly-Si layers with a thickness, d=2 mm, formed on textured Ag/SnO₂/glass in the range of RMS based-textured substrate (a) s=85nm, (b) s=42nm and (c) s=2nm respectively. Influences of the substrate texture on the crystal growth as well as the local current flow are discussed. Where we found that the average of local current proportional with crystallinity, where the poly-Si layer that has rich crystallinity indicated low conductivity that yield high local current.

Abstract: By the method of thermal oxidation of n-type CuInSe2 crystals, n - n+ structures with a maximum absolute current photosensitivity of up to 10 mA / W were obtained at low rectification and no-load photovoltage. The used modes of thermal oxidation led to the formation of n-type layers on the surface of the n-CuInSe2 plates, the resistivity of which is 2-2.5 times higher concerning the initial substance. Measurements of the stationary current-voltage characteristics have shown that the structures obtained have a slight rectification K. All the structures obtained exhibit photosensitivity, which dominates when illuminated from the side of the layer in the spectral region of about 1 eV. The optimization of the process can reveal the technological possibilities of a significant improvement in the rectifying properties of isotypic structures based on CuInSe2.

Abstract: In this manuscript, we analyze the viability of waterborne polyurethanes (WPU) and compounds derived from WPU mixtures, for applications of these materials in the electrical, electronic, and energy fields as insulation and anti-electrostatic applications. In the current research, several applications type of neat WPU, with any reinforcement, and WPU polymer blends have been studied and compared with standard criterions from the International Electrotechnical Commission (IEC) and Standardization Association from Spain (UNE). To analyze the feasibility in different industrial applications selected, certain compounds obtained from the WPU blends were analyzed regarding their use in eleven low requirement insulator and anti-electrostatic applications. The research and analysis developed in this manuscript used standard data from the UNE – IEC norms, and these standard values were compared with the obtained research values from scientific literature and recent research published experiences. The obtained results were used to provide an application list that could be helpful for industrial applications. In this research, the analyzed WPU compounds neat WPU, Fe3O4 WPU composites, among other nanocomposites WPU blends, which has been currently published in research works, journals, and conferences. We have discovered some possible useful applications for WPU with any reinforcement, mainly as insulators and for WPU nanocomposite blends for anti-electrostatic uses, mainly dielectric and mechanical features compared, however other test types are needed to obtain like flame resistance, thermal behavior, or another key aspect to analyze in deep.

Abstract: The thermoelectric properties of compounds with variable valence Mn_1-ХRe_ХS (0 ≤ X ≤ 0.2) in the temperature range of (80 – 1100) K are studied. The maxima on the temperature dependences of the Seebeck coefficient (thermal EMF) for all substitution concentrations and the change of the sign of the Seebeck coefficient from positive to negative with an increase in the substitution concentration in Mn_1-XYb_XS are determined. A model of impurity donor 4f-states is proposed and a satisfactory agreement with the data on the thermal EMF is obtained.

Abstract: An experimental investigation was conducted in order to study the water absorption, mechanical performance, thermal properties and durability of hybrid hemp-rapeseed composite materials. The hybrid composite material is made with 50% hemp shives and 50% rapeseed fibres. The purpose of this study is to investigate the influence of the incorporation of viscosity modifying agent (VMA) on hybrid concrete. Four mixes were made for: shuttered walls and roof insulation with and without VMA. The water absorption of the hybrid composite fibres was, first, measured. The compressive strengths of these mixes at 7 and 28 d were then determined in order to compare the mechanical behaviour of the hybrid composite materials made with VMA. In addition, the capillary absorption and coefficient of thermal conductivity were also measured. The results revealed that VMA improved the performance of the hybrid concrete.

Abstract: Lithium iron phosphate (LiFePO₄) based material is one of the most prospective candidates as a cathode material in lithium-ion batteries because of its lower cost, safer, and environmental benignity compared to lithium cobalt oxide (LiCoO₂), which is commonly used for lithium-ion batteries manufacturing. However, its low conductivity is the obstacle of this material to solve, so that modification with the addition of silicon (Si) is expected to improve the electrochemical performance. Meanwhile, solid state reaction is considered simple and effective in LiFePO₄ crystal growth process. Therefore, Si-doped LiFePO₄ using solid state reaction in this research aims to study its structure and morphology as well as the effect of adding Si to its conductivity. The synthesis began with mixing LiH₂PO₄, Fe₂O₃, carbon black, and six-mole ratio variation of Si to LiFePO₄ using agate with ethanol: acetone addition then dried in an oven at 80°C and heated at 550°C in a furnace for 6 hours under argon atmosphere and sintering temperature of 870°C for 16 hours with the same condition. The sample of 3% mole ratio performed the highest conductivity of all variations with 3.01 x 10^-6 S.cm^-1, and was identified as Li_0.93Fe_1.07P_0.93O₄Si_0.7 with orthorhombic structure, Pnma space group (Ref. Code: ICSD 98-016-1792) with the highest peak at 2θ = 35.556° from XRD analysis with rectangular-like shape particle.