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Journal of New technology and Materials

“Journal of New technology and Materials”(JNTM) is an international peer-reviewed journal that publishes high quality original works on the Material sciences (physics, chemistry and life sciences) and engineering. It covers the aspect of materials science and engineering in all forms, particularly materials associated with new technologies (nanoscience and nanotechnology).
JNTM Journal provides a platform for researchers, students and industrialist to submit on-going research and developments in material and technology areas. Authors are solicited to contribute to the JNTM journal by submitting articles that illustrate research results and projects that describe significant advances in all areas covered by our scientific journal (JNTM).

Articles de cette rubrique

Effect of a buffer layer on the Performance of Thin-film Cu(In,Ga)Se2 Solar Cells

Copper indium gallium diselenide (CuIn1-xGaxSe2 or CIGSe) solar cells has been considered to be one of the most promising thin-film solar cells and is important for terrestrial applications because of their high efficiency, long-term stable performance and potential for low-cost production. In this work, the CIGS heterojunction solar cell has been numerically simulated using SCAPS-1D tool. We study the influence of a buffer layer on the performance of the CIGSe solar cells. Quantum efficiency, Jsc ,Voc and efficiency has been calculated in different buffer layer materials (CdS, ZnS, ZnSe, InS).The solar cell optimized shows an efficiency of > 18% under the AM1.5G spectrum and one sun.

Fabrication, structural and optical characterization of In doped ZnO thin films prepared by the colloidal method

Regarding to the excellent conductivity and high transparency in the visible range, the zinc oxide (ZnO) films have been widely used as transparent electrodes in optoelectronic devices, ZnO is a direct wide band-gap (3.37 eV) semiconductor.
The conductivity of ZnO will be largely enhanced by doping little In, but it still keeps high transparency. So, IZO film has been widely investigated and is considered to be a promising possible alternative to ITO films.
This work consist to the fabrication and characterization of ZnO:In thin films. The sample preparation was carried out by the colloidal method. The pure and In doped ZnO thin films were deposited using a dip-coating technique on glass matrix. The optimal condition for samples fabrication has been investigated. The XRD and Raman characterizations show that the ZnO thin film crystallize with a wurtzite structure. The optical properties of ZnO thin films doped In reveal that doping changes the optical gap of ZnO.

Channel drop filter based on coupled cavity in photonic crystals

In this paper, a five channel drop filter has been designed in a two dimensional photonic crystal with high dielectric rods in air. Each channel consists of a photonic crystal coupled cavity waveguide with double cavities combined with a line defect waveguide. Desired wavelengths are selected by setting different radii of the two point defects in the photonic crystal coupled cavity waveguides. Defect rods placed at the same channel have an identical radius. The performance of the designed filter has been numerically calculated using the finite difference time domain method. In the designed structure, higher efficiencies in all channels have been achieved.

Copper oxide thin films deposition by spray pyrolysis

CuO thin films have been growth on to heated glass substrates by varying substrate temperatures from 280 to 400°C. The effect of the pyrolysis on structural, optical and electrical proprieties of CuO films has been investigated in the present work. Phase analysis was carried out using Micro-Raman scattering. The optical properties were studied by mean of UV–visible and near infrared spectroscopy. The conductivity was measured by the electrical D.C transport. The structural analysis indicates the presence of a single CuO phase with a monoclinic structure. The optical transmittance spectra show a high absorption of all films in the visible region. The electrical characterization indicates a maximal electrical conductivity of 1,03 × 10-6 (Ω .cm)-1.

Two-dimensional Modelling and Simulation of CIGS thin-film solar cell

2 D Silvaco Atlas software is used for the study of a CIGS thin film solar cell in the configuration : ZnO(200 nm)/n-type CdS(50 nm)/ p-type CIGS(350 nm)/Mo. The cell performance is evaluated by implementing the defects created at the grain boundaries of the polycrystalline CdS and CIGS material and at the interface CdS/CIGS.The J-V characteristics and the external quantum efficiency EQE are simulated under AM 1.5 illumination. The conversion efficiency  of 20.35% is reached and the other characteristic parameters are simulated : the short circuit current density Jsc equals 35.62 mA/cm2, the open circuit voltage Voc is of 0.69 Vand the fill factor FF is of 82.7 %. The calculated external parameters of the solar cell are in good agreement with the measured characteristics. The simulation results also showed that the rise of the CdS thickness decreases all output parameters and the external quantum efficiencywhile the rise of the CIGS thickness improves all photovoltaic parameters and the external quantum efficiency. The highest efficiency of 21.08 % is reached for the CIGS thickness of 5 μm.

New Approach to Modeling a planar flexible continuum robot simulating elephant trunkt

Research on the modeling of continuum robots is focused on ways to construct the geometric models, while maintaining maximum specificities and mechanical properties of the robot. This paper presents a new approach of geometric modeling of continuum planar multi- sections robots, assuming that each section is curved in a circular arc, while having inextensible central axis of the structure. The direct geometric model is calculated analytically, whereas the extreme points (used in calculating the inverse geometric model) of each section are calculated numerically using a particle swarm optimization (PSO) method. One advantage of this method is to simplify the mathematical calculations and transform the complex problem into a simple numerical function ; which allows the knowledge of the form of the central axis of the robot. Simulation examples using this method are carried to validate the proposed approach.

Effect of surfactants in the synthesis of NiO nanoparticles bycolloidal thermal assisted reflux condensation method

Nickel oxide (NiO) nanoparticles were prepared by colloidal thermal assisted reflux condensation method using nickel acetate (precursor salt) and N, N - Dimethylformamide - DMF (solvent) with or without the addition of surfactants such as cetyl trimethyl ammonium bromide (CTAB), polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA) and sodium monododecyl sulphate (SDS) respectively. Finally, the prepared samples products were calcined at different temperatures systematically such as at 200oC, 400oC, 600oC, 800oC for 2 hrs each to get the phase pure product. The calcined nanoparticles were characterized by X-Ray Diffraction (XRD), Energy Dispersive X-ray Analysis (EDAX), Fourier Transform Infrared (FTIR) Spectroscopy, Particle Size Analysis, Scanning Electron Microscopy (SEM), Diffuse Reflectance Spectroscopy (DRS) and Photo Luminescence (PL) Spectroscopy techniques. All the samples were crystallized in cubic structure. Effect of surfactants in the synthesis of nickel oxide (NiO) particles is discussed and reported.

Nd:Yag Laser Ablation of Recuperated and Industrial Aluminum Alloys. Study of Threshold Ablation

In this work, we used a nanosecond Nd : Yag laser (=532 nm) with a pulse duration of 15 ns, and an energy of 50 mJ and, therefore, we studied the threshold ablation of industrial aluminum alloy. The composition of the recuperated aluminum (% mass) is (72.02 Al, Si 13.05, 6.34 Zn, 4.28 O, 2.08 Mg, 1.75 Cu, 0.48 Ni) and the industrial aluminum is (83.10 Al, 1.66 Si, 4.12 Fe 2.17 O, 1.20 Mg, 5.47 Cu, 1.74 Mn, 1.79 Pb). For nanosecond lasers, the primary energy is lost by thermal diffusion in the irradiated target, because there is enough time to convert optical energy into thermal energy and heat spread. Fusion and / or evaporation may take place if the surface temperature exceeds the critical point when the energy of radiation is above the ablation threshold. The results shows that the threshold ablation of the recuperated aluminum is lower than that of the aluminum industry, it is about 5 J.cm-2 for the recovered aluminum and 10 J.cm-2 for the industrial aluminum. The threshold ablation is shifted towards the low values when the number of pulses increases.

Irradiance and temperature impact on thin film materials I-V curves

The thin-film solar cells are becoming increasingly used in various applications ; this is mainly due to the continued high cost of mono or polycrystalline silicon. In addition, the thin film technology offers the most diverse applications including uses low solar irradiance. The main fields of thin film solar cells are : the chain of amorphous silicon (a-Si), the chain of cadmium telluride (CdTe) and chalcopyrite sector (CIS and CIGS material). In this paper, a study on the influence of light and temperature on the characteristics I (V) of different thin film photovoltaic cells (a-Si:H single, a-Si:H tandem a-Si:H tripple, CdTe and CIS) is detailed. Under standard conditions (illumination of 1000W/m2 and cell temperature 25° C), we see that the CdTe is the closest that the monocrystalline silicon which has a maximum value of short circuit current material (3,26A).

Nanopowders prepared by Solar Physical Vapor Deposition (SPVD)

The Solar Physical Vapor Deposition (SPVD) is an original process to prepare nanopowders. This method has been developed in Odeillo-Font Romeu in France using solar reactors working under concentrated sunlight in 2kW solar furnaces. Various oxides, pure or containing other elements in addition, have been obtained. This paper focus on ZnO and TiO2. based oxides It is shown that the X-Rays Diffraction analysis allows a fine nanostructural characterisation of the nanophases present in these nanopowders. In many cases, HRTEM or SEM and XPS complement the XRD analysis. The properties such as Electrical, magnetic properties, photoreactivity, luminescence … known on microstructured materials of the same composition are revisited on these nanopowders or on nanomaterials prepared from them and led in many cases to original behaviours.

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