Papers by Keyword: Spray Pyrolysis

Abstract: Spherical fine Ni particles were prepared by ultrasonic spray pyrolysis, and the effects of starting materials, carrier gas, and pyrolysis temperature on the crystal phase of the fine particles were investigated. When the mist of starting solution was pyrolyzed at 850 °C in a N₂ atmosphere, the crystal phase of fine particles obtained from Ni (CH₃COO)₂·4H₂O was in good agreement with that of Ni. Furthermore, the other phases were not observed. The average particle size of the spherical Ni fine particles was 0.45 μm.

Abstract: Effect of Co-doping on gas sensing, electrophysical and structural properties of the SnO₂ films deposited by spray pyrolysis has been studied. It is found that the influence of Co-doping on parameters of the SnO₂-based gas sensors depends on the concentration of doping additives and could be accompanied by either improvement of sensor parameters at low levels of doping (C_Co< 2-4 %) or degradation of the gas sensor operation characteristics while the concentration of additives exceeds 2-4%. An explanation of observed effects is given.

Abstract: In this paper we present results of structural analysis of SnO₂ films deposited by spray pyrolysis and designed for application in conductometric gas sensors. The aim of this analysis was summarizing the results obtained in this field, highlighting a correlation between material structure and its gas sensing properties, and formulating some general regularities typical for metal oxides.

Abstract: Spherical Li₂Ti₃O₇ precursor powders were successfully prepared by spray pyrolysis. X-ray diffraction analysis revealed that the ramsdellite phase was obtained by calcining at 1100 °C for 3 h under an argon/hydrogen (95/5 %) atmosphere. The Li₂Ti₃O₇ anode exhibited higher rechargeable capacity and excellent cycle stability. The rechargeable capacity of the Li₂Ti₃O₇ anode was approximately 168 mAh/g at 0.1 C. The discharge capacity of the Li₂Ti₃O₇ anode after 100 cycles was approximately 90% of the initial discharge capacity.

Abstract: Li₄Ti₅O₁₂ powders were synthesized via the solid state reaction of Li₂CO₃ and spherical composite powders of carbon and TiO₂ (denoted by C/TiO₂) with different microstructures. These C/TiO₂ powders were synthesized by spray pyrolysis using various organic acid aqueous solutions. The particle characteristics of the resulting carbon composite Li₄Ti₅O₁₂ (denoted by C/Li₄Ti₅O₁₂) powders were determined using SEM, XRD, and DTA-TG. DTA-TG showed that the carbon content of all Li₄Ti₅O₁₂ powders. was around 3 wt%. XRD revealed that the spinel structure (Fd3m) was obtained by heating at 750 °C under N₂ atmosphere. The initial rechargeable capacity of the C/Li₄Ti₅O₁₂ powders formed using citric acid was approximately 170 mAh/g at 1 C. The rechargeable capacity of the C/Li₄Ti₅O₁₂ powders decreased with an increase in the rechargeable rate. The anodes maintained over 90% of their initial discharge capacity after 200 cycles at 1 C. The C/Li₄Ti₅O₁₂ powders also demonstrated high cycle stability at 50 °C. It was found that rechargeable capacity was influenced by the particles microstructure, but cycle stability did not depend on the microstructure.

Abstract: This paper presents the design of the user interface for a robotic spraypyrolysis system used in deposition on planar surfaces. The study takes into consideration theoptimization of the control characteristic parameters at the spraying process. CAD software environment is used to design thevirtual model at the robotic system, while RobotStudio is used to develop theuser interface. The design variables for optimization refer tothe spray pyrolysis deposition parameters (the number of passes, the pressureof the carrier gas, the orientation and the velocity of spray nozzle, thetemperature of the substrate). The main purpose of the paper is to obtain materials with controlled properties byspray pyrolysis, using a simple algorithm. The surfaces resulted by spraypyrolysis were analyzed using theAFM (Atomic Force Microscopy) technique.

Abstract: CdZnS thinfims have been prepared on mineral glass substrate by spray pyrolysis method at different deposition temperature using the optimized coating parameters. The XRD profile of the films confirms hexagonal wurtizite structure with preferred orientation along the (101) pane. The different crystallographic parameters viz., lattice constant, c/a ratio, mean grain size, number of reflections per unit area, lattice strain, dislocation density, texture coefficient and standard deviation have been calculated from the experimentally observed XRD data and the effect of deposition temperature on these parameters have been elaborately discussed. The maximum optical transmittance of 84.5% (at λ= 650 nm ) has been observed for the CdZnS thin film spray deposited at the temperature 450 °C. The direct band gap energy calculated from the transmittance measurements lies between 2.82 eV and 3.4 eV. The electrical resistivity has been found to be low with the value 50 x 103 Ω - cm for the film deposited at the temperature 450 °C. The SEM micrographs of the films show uniform surface pattern associated with large accumulation of fine grains. The grain size estimated from the SEM analysis lies between 100 nm and 350 nm.

Abstract: Sb-doped SnO2 (ATO) films were successfully prepared by the spray-pyrolysis method with SnCl2•2H2O and SbCl3 as precursors. The structural, surface morphological, electrical and optical properties of the films were studied in details. The results indicated that all films consisted of tetragonal cassiterite SnO2 with preferred orientation along (110) and (200) crystal plane. A minimum resistivity as low as 1.59×10-3 Ω∙cm has been achieved. The infrared emissivity of the films on the surface of glass was ca. 0.36, which presents potential application in the low-emission window and building ceramics.

Abstract: Emergenceof innovative technological deposition technique of spray pyrolysis enabled the enhancement of structural, optical, and electrical properties of Sn1-xCrxO2 (x=0.0, 0.02, 0.04, 0.06, 0.10, 0.15) transparent semiconductors thin films in the present study. To evaluate these properties, X-Ray diffraction (XRD) spectroscopy were usedto study the elemental component and the crystalline nature of the materials while the optical properties and structure of the samples were evaluated using UV—vis spectroscopy and field emission scanning electron microscopy (FE-SEM).Finding showed that the Cr-doped SnO2 films were tetragonal in shape. Transmission spectra of the deposited films showed high transparency of ~ 70-90% in visible region with optical edge of 3.7eVfor SnO2. Resistivity of pure tin oxide samples was 0.01 Ω-Cm and increases with increase in dopant level. The Hall voltage showed that the type of semiconductor changed with increasing of dopant.

Abstract: The structural, electrical, and optical properties of spray deposited tin-doped indium oxide (ITO) films are reported in this work. The films have excellent properties, as a transparent and conducting electrode, for applications in a wide range of areas of optoelectronics such as photodetection and photovoltaic. One example of the ITO thin films application in semiconductor-insulating-semiconductor (SIS) efficient solar cells and modules is shown.