Papers by Keyword: Spray Pyrolysis

Abstract: Solar energy is one of the most important sources of renewable energy today. The production of electric energy is based on silicon cells, which are expensive and difficult to produce and therefore, New preparation methods, materials or approaches are needed. This work aims to deposit Tin oxide doped with fluorine, prepared by sol-gel, on a glass substrate using the spray pyrolysis technique. F-SnO₂ (FTO) solution was synthesized by sol-gel method, employing NH₄F and SnCl₂ precursors in an ethanol solution. Before the formation of the gel, the solution was sprayed using a pistol aerographic, On a substrate at approximately 600oC. This process was repeated 50 times, and after that, the sample was cooled until room temperature inside the furnace. The obtained samples (substrates for the PV cell) present a resistance between 10 and 30 Ω. The energy dispersive x-ray (EDS) was used to confirm the presence of fluorine in the SnO₂ network.

Abstract: The spray pyrolysis was employed to prepare Lanthanum Sulphide (La₂S₃) thin films on silicon non conducting glass substrate using lanthanum chloride and thioacetamide from aqueous medium. The effect of preparative parameters on film properties was studied. Further thin films characterization was carried out by electrical resistivity, thermoemf, optical, XRD and SEM measurement techniques. The electrical resistivity was the order of 10⁴ – 10⁵ Ω cm and it shows semiconducting behavior. The Thermoemf studies reveal that Lanthanum Sulphide material is P-type. The direct band gap of Lanthanum Sulphide (La₂S₃) thin films was estimated to be 2.5 eV. The XRD studies indicate that Lanthanum Sulphide (La₂S₃) thin films are polycrystalline. A morphological study shows that the Lanthanum Sulphide (La₂S₃) thin films have fibrous network.

Abstract: The performance of copper indium gallium disulfoselenide (CIGSSe) solar cells strongly depends on the band bap of absorbing layer of CIGSSe. The device performance can be improved by fabricating multi band gap layer of CIGSSe. However, the fabrication of multi band gap CIGSSe using non-vacuum techniques is challenging. In this study, we fabricated solar cell devices which consisted of multi band gap Cu (In,Ga)(S,Se)₂ thin films. The CIGS thin films were prepared by the spray-pyrolysis of aqueous precursor solutions of gallium (gallium chloride; GaCl₃), copper (indium chloride; CuCl₂), indium (indium chloride; InCl₃), and Sulphur (thiourea; (SC(NH₂)₂) sources on Mo-coated glass substrate. The as-sprayed thin films were then selenized at 500 °C for 10 minutes.After selenization, CIGS films were transformed to Cu (In,Ga)(S,Se)₂ (CIGSSe). The CIGS films with different composition were deposited again on top of selenized CIGSSe films and selenization process was repeated, hence multi band gap CIGSSe films were fabricated. The Chemical bath deposition (CBD) process was used to deposit cadmium sulphide (CdS) buffer layer. The solar cell fabricated with the device configuration of glass/Mo/CIGSSe/CdS/i-ZnO/AZO showed a power conversion efficiency of 6.51%.

Abstract: Titanium dioxide (TiO₂) is coated onto the materials (e.g. glass ceramic) to inhibit the bacteria growth. TiO₂ has become a popular photocatalyst for both air and water purification. It has also shown to be very active for bacterial destruction even under UV light. The photocatalytic of TiO₂ involves the light-induced catalysis of reducing and oxidizing reactions on the surface of materials. The spray pyrolysis technique for material synthesis in thin-film configuration is an interesting option due to the use of inexpensive precursor materials and low-cost equipment suitable for large-area coatings. In this research, TiO₂ thin films were deposited onto glass substrates using spray pyrolysis technique. Escherichia coli (E.coli) was used as testing bacteria. TiO₂ thin films showed some antibacterial effect in the halo test.

Abstract: In this report it is being discussed approaches for designing the SnO₂ and In₂O₃ ozone sensors based on the film parameters optimization. It was considered the influence of the conditions of the SnO₂ and In₂O₃ films deposition by spray pyrolysis method and the parameters of those films on operating characteristics of ozone sensors. Main factors, controlling operating characteristics of thin film ozone sensors were determined. Recommendations to process of the SnO₂ and In₂O₃ films deposition, promoting an attainment of optimal operating gas sensing properties, were formulated.

Abstract: Spherical SrMoO₄:Eu³⁺ phosphors had been prepared by spray pyrolysis. The effect of the total solution concentration on phase structure, microscopic morphology and fluorescent performances of SrMoO₄: Eu³⁺ phosphor have been studied. The results showed that pure SrMoO₄ phase can be obtained at different total solution concentration; The luminous intensity of the sample was the strongest at 615nm when the total solution concentration is 0.6M. SrMoO₄: Eu³⁺ phosphor with regular spherical morphology, well dispersion and well fluorescent properties was synthesized successfully by spray pyrolysis method.

Abstract: Fluorine doped tin oxide (FTO) thin film was prepared by using two different precursor solutions which are tin (ii) chloride dihydrate and tin (iv) chloride pentahydrate. These two precursors are used in spray pyrolysis process to prepare the fluorine doped tin oxide thin film. Surface Morphology of the thin film was characterized using field emission scanning electron microscope (FE-SEM). FESEM image shows the particle distribution and the morphology of fluorine doped tin oxide thin film. Two point probe I-V measurement and UV-Vis spectroscopy were used to study the electrical and optical properties of both films. Both precursors produced different particles distribution, electrical properties and also optical properties. The results show that the sheet resistance (Rs) of fluorine doped SnO₂ is about 49.24×10⁶Ω for tin (iv) chloride pentahydrate compared to 43.03×10¹²Ω for tin (ii) chloride dihydrate

Abstract: In the present research, zinc oxide (ZnO) films have been prepared by simple solution method and spray pyrolysis on different substrates (glass and sapphire) for different molar concentrations (0.2M & 0.25M). The films were subjected to different substrate temperatures (400 °C and 450 °C respectively. These were characterized for SEM and XRD and the average size of the crystallites were in range of 300 and 200nm for the films on Saphire and glass at higher substrate temperature. FTIR analysis has been carried out and optimization conditions were used in order to confirm the significant peaks and phase transformation. The films were subjected to ethanol gas for these substrates and corresponding electrical properties were carried out by two probe method and was found that the films for sapphire substrate prepared by spray pyrolysis method showed more conductance at higher temperatures than glass. Optical properties were also studied for these films and was found that films prepared by spray on sapphire shows less transmittance at higher substrate temperatures in comparison to the films on glass.

Abstract: In this paper, gas sensing property of a nitrogen doped ZnO was studied. nanofilms of pure and nitrogen-doped ZnO (0.1, 0.2 and 0.3 normality) were prepared on glass substrate by spray pyrolysis technique. These films were fired at 450°C for two hours in air atmosphere. nanobehavior of the films was confirmed by XRD and SEM analysis. Gas sensing behavior of the films was tested in static gas sensing system. Films were exposed to different gases as LPG.NH3, NO2, Ethanol vapour and CO2 at different ppm concentrations and different operating temperatures. Pure ZnO films showed poor sensing behavior. At 150°C, films of N-doped ZnO (0.3 normality) showed good sensing for Ethanol vapours. The gas sensitivity was determined as 86.8% for 200 ppm of Ethanol vapours. When compared with pure ZnO, the nitrogen doped ZnO films possessed more oxygen deficient species. Due to this crystal defects arising from nitrogen doping, the improvement in gas sensing property of ZnO may be argued. Keywords: Spray pyrolysis; ZnO; N; XRD; SEM; LPG

Abstract: With lanthanum chloride solution as raw material, and use the hydrogen peroxide of clean and pollution-freeobtained from oxidation reaction as auxiliary reagent, and with the carrier gas together form spray pyrolysis to obtain lanthanum oxide. On the one hand, in the hydrogen peroxide system, the temperature of direct pyrolysis reaction of lanthanum chloride solution decreased obviously, The reaction temperature is decreased from 1280°C to 1000°C or less. That reduce the energy consumption and simplify the requirements of pyrolysis equipment technology. The production process does not use NH₃^.H₂O and NaOH to precipitate. It does not produce the traditional process of NH⁴⁺, Na⁺ to pollute water. It can greatly reduce the damage to the environment, and can product with high yield, high purity of the rare earth oxide. This method not only applies to the pyrolysis of the rare earth chloride solution, also applies to metal chloride solution, such as FeCl₃, AlCl₃, NiCl₂. It was shown that the reaction temperature has been effectively reduced, V_LaCl3: V_H2O2 with 1: 1.5 can get high purity of La₂O₃.