Papers by Keyword: PbS

Abstract: In this paper, polyethylene terephthalate (PET) fibers were blended with a biodegradable polymer, poly (butylene succinate) (PBS) was investigated in this study. The melt-spinning process produced PET/PBS fibers at the different PBS contents in the PET matrix. We evaluate the effectiveness of the dyeability of PBS contents in PET fibers. The yellow organic dye (Turmeric extract) was used as a coloring agent. The spectrophotometer results show that the dye absorption of the fiber increased with PBS contents. The SEM images confirm the relationship between the dye coating on the fiber and PBS contents in the PET matrix. This indicates that the PBS can act as a compatibilizer or modifier to improve dye penetration and fixation in PET/PBS fibers.

Abstract: Lead Sulphide, PbS thin films deposited on glass substrates by a chemical bath deposition method, which is a simple and easily controlled technique. The reactive substances used to obtain the PbS layers were (Pb(NO3)2), NaOH, Sc(NH2)2 and H2O for different dipping concentrations of lead nitrate, dipping times and temperatures. The films were structurally characterized by X-ray diffraction studies. The films are very adherent to the substrate and well crystallized according to the face centered cubic structure with the preferred orientation (1 1 1). The films were optically characterized by the transmission and reflectance spectrum, examined by a UV – VIS Spectrophotometer. In the infrared range, low transmittance and reflectance are detected (between 10% and 30%), while there is no transmittance or reflectance in the UV and visible regions. It can be seen from absorption spectra that absorption is stronger in the UV and UV-VIS region and gradually diminishes. Maximum absorption is observed in the visible and ultraviolet range, which indicates that the film prepared is of nanocrystalline. The band gap of PbS can be varied in the range of 0.41 to 2.71 eV, which is a significant material feature and opens the door to a new class of applications. The calculated band gap was determined to be between 1.88eV and 2.1eV.

Abstract: A resistive ethanol gas sensor with a high sensitivity has been proposed. The fabricated gas sensor has a very promising response and recovery at room temperature. The proposed sensor has been fabricated by depositing sensitive nanostructured material on printed circuit board interdigitated electrodes. As the sensitive material, ZnO nanorods of high uniformity have been synthesized by hydrothermal method and then decorated by PbS nanoparticles. The synthesized decorated nanorods were characterized by X-ray diffraction and scanning electron microscope which confirmed the formation of the desired nanostructures. The ethanol gas sensing properties of the ZnO nanorods decorated with PdS nanoparticles was measured in a test chamber. The minimum ethanol concentration detected by the sensor has been 10 ppm. The results showed the higher sensitivity of the proposed sensor to the ethanol at room temperature compared to similar works.

Abstract: In this study, PbS thin films were produced at a low temperature such as 15Co using the chemical bath deposition (CBD) method.0.0085 M Pb (NO3)2 and 0.1460 M NaOH were dissolved in 100ml deionized water. 0.510 M thiourea which would be added to the solution was divided into 10 portions and added at zero, two, four, six and eight-minute intervals. Structural analysis of the obtained samples was carried out from XRD patterns which showed a significant increase in the peak intensity of the films obtained by adding thiourea at intervals of four and six minutes. The surface morphologies of the films were analyzed using a scanning electron microscope. According to the SEM images, when thiourea was added to the solution at intervals of four minutes, no cracks and holes were formed on the surfaces of the films obtained.

Abstract: PbS thin films were successfully prepared by chemical bath deposition at low temperature of 40, 50 and 60°C using an improved transparent precursor solution which contained 0.05 M lead nitrate, 0.2 M sodium hydroxide, 0.2 M triethanolamine and 0.06 M thiourea. The obtained PbS thin films appeared smooth and compact, and the crystal sizes were calculated to be 62 nm, 131 nm, 254 nm by Scherrer's equation at deposition temperatures of 40, 50 and 60°C, the corresponding band gaps were estimated to be 1.58 eV, 1.38 eV and 1.20 eV, respectively. The work function of the PbS thin films were measured by Ultraviolet Photoelectron Spectroscopy and they were –4.90, –4.60 and –4.50 eV, respectively. The valence and conduction band edges of the PbS thin films were calculated from the work function and optical band gap values. What is more, the optimized PbS/TiO₂ heterojunction thin film solar cell combined with spiro-OMeTAD hole-transport layer was fabricated and obtained the photoelectric conversion efficiency of 0.24%.

Abstract: We study the threshold voltage (V_th) instability of commercially available silicon carbide (SiC) power MOSFETs or prototypes from four different manufacturers under positive bias temperature stress (PBTS). A positive bias near the V_th causes a threshold voltage shift of 0.7 mV per decade in time per nanometer oxide thickness in the temperature range between-50 °C and 150 °C. Recovery at +5 V after a 100 s +25 V gate-pulse causes a recovery between-1.5 mV/dec/nm and-1.0 mV/dec/nm at room temperature and is decreasing with temperature. All devices show similar stress, recovery and temperature dependent behavior indicating that the observed V_th instabilities are likely a fundamental physical property of the SiC-SiO₂ system caused by electron trapping in near interface traps. It is important to note that the trapping is not causing permanent damage to the interface like H-bond-breakage in silicon based devices and is nearly fully reversible via a negative gate bias.

Abstract: MP/PBS composite was fabricated by melt blending method. The weight loss ratio of MP/PBS composite reached 35.43 wt.% after immersion into phosphate buffered saline solution for 12 weeks, and the pH change from 7.40 to 7.72. The relative proliferation rate of cells on the materials increased with time and the proliferation of the cells on the MP/PBS composite was significantly higher than PBS. The results reveal MP/PBS composite has good biocompatibility, which satisfied the relevant criterion on biomaterials.

Abstract: Chopped carbon fiber (CF) reinforced PBS/CF composites were prepared by twin-screw extrusion processing. The effect of adding a certain quantity of CF in composites on the tensile, flexural and impact properties have been investigated. The results indicated that the tensile properties, flexural properties and impact properties of the PBS/CF composites were first improved and then decreased with the increase of the content of CF.

Abstract: This paper concerns about Large-scale mosaic for remote sensed images. Base on High Performance Computing system, we offer a method to decompose the problem and integrate them with logical and physical relationship. The mosaic of Large-scale remote sensed images has been improved both at performance and effectiveness.

Abstract: This study reports on the fabrication of a Schottky solar cell with a cross-sectional schematic: ITO/PbS/Al with a commercial transparent conductive ITO and a p-type PbS absorber layer deposited by using a thermal evaporator. The structural and optical properties of constituent films are presented. X-ray diffraction showed that the thin films are polycrystalline. By using scanning electron microscopy, this study showed that the films possessed a uniform surface morphology over the substrate, and the films exhibit a nanocoral structure. Open circuit voltage,short-circuit current density and characteristics were studied under 30 mW/cm² solar radiation.