Papers by Keyword: Spray Pyrolysis

Abstract: In this study, SnO₂ was successfully synthesized using spray pyrolysis method. Knowing that lanthanides has the capability to enhance the performance of metal oxides in supercapacitor application, Samarium was loaded to Tin Dioxide (SnO2) at different percent weight concentrations (0.5%, 1%, 3% 5%). XRD diffractograms shows the formation of tetragonal rutile structure with prominent peaks at 26.6°, 34.08°, 51.94° that corresponds to (110), (101), and (211) respectively and no additional peaks was detected with the incorporation Sm³⁺ ions which. The data obtained from Energy Dispersive X-ray Spectroscopy confirm the presence of Sm on the spray pyrolyzed SnO2. Scanning electron micrograph revealed that the increase in loading of Sm changes the morphology of the samples from 1D to 2D structures. Faradaic reactions indicated by the oxidation and reduction peaks were monitored using cyclic voltammetry in 1M KOH electrolyte. The specific capacitances were determined by analyzing the galvanostatic charge discharge profile of each sample. SnO₂ with 0.5% Sm yield the the highest specific capacitance, energy density and power density of 54.55 F/g, 1.60 WHr/kg, and 230 W/kg respectively. The results from this research offers a valuable information in synthesizing binder-free electrode and modifying its properties by incorporating samarium. These electrodes can be used for advanced applications such as electrochemical energy storage device, electrochemical sensors, and electrocatalytic applications.

Abstract: Undoped and Ni-Eu co-doped ZnO thin films were successfully fabricated via spray pyrolysis at 400°C. The impact of co-doping on the structural, morphological, electrical, and optical properties of the thin films was thoroughly investigated. X-ray diffraction (XRD) analysis confirmed the absence of secondary phases and verified the successful incorporation of dopant ions into the ZnO lattice. Morphological examination revealed enhanced crystallization and a more uniform surface following the incorporation of nickel. Spectral studies in the UV-Vis region were conducted to determine the optical band gap of the synthesized ZnO films, indicating a slight decrease in bandgap values and volume and surface energy losses (VELF and SELF) with increasing Ni doping concentration. Photoluminescence spectra exhibited emission peaks in the UV region around 415 nm and broad visible emissions spanning 450-650 nm for all samples. Electrical characterization using Hall Effect measurements confirmed n-type electrical conductivity in all prepared films, as evidenced by the observed negative Hall coefficients. The co-doped ZnO thin films, particularly those incorporating Ni-Eu, show promise for applications in electronic and optoelectronic devices. Additionally, we investigated the photodegradation of green malachite under a UV lamp. Remarkably, the results demonstrated degradation rates of 93% within 2 hours, showcasing promising potential for practical applications.

Abstract: In this present work, Pristine and 10 at.% of In-doped ZrO₂thin films were deposited by spray pyrolysis technique at optimized substrate temperature [Ts=450°C]. The greater the proportion of Indium ion dopant, significantly influences the structural, optical, morphological, and electrical properties of deposit thin films. The deposited thin films were characterized with XRD, UV-Vis, PL, HR-TEM with EDAX, and I-V characterization Studies. The crystallinity of Zirconium dioxide thin film was improved and size of crystals were decreased by Indium ion substitution. Optical study revealed that the film's optical transmittance enhanced from 80.3 percent to 86.5% as a result of the dopant. The energy bandgap increased at 4.93eV - 4.57eV, systematically. HR-TEM studies show the homogeneous particle distribution and denser surface texture at 22nm and 19nm of average particle agglomerations. The study of PL emission shows an increase in intensity on the blue emission band with enriched crystalline quality. The conductivity of the ZrO₂ was higher affected by Indium ion may result in increased conductivity, with low resistivity property.

Abstract: Tin disulfide (SnS₂) thin films have drawn worldwide attention because of their outstanding performance and earth-abundant constituents. However, problems such as coexistence of complex secondary phases (SnS, Sn₂S₃), the band tailing issue, and bulk defects need to be addressed for further efficiency improvement. In this regard, the present work is intended for the treatment of one of these problems. Herein, a single phase SnS₂ has been obtained using an ultrasonic spray pyrolysis method. which is confirmed by X-ray diffraction (XRD) and energy dispersive X-rays (EDXs) characterization techniques. The substrate temperatures (Ts) were increased from 250 °C to 450 °C, and this significantly improved the film's characteristics, which varied from an amorphous phase and a mixture of crystalline phases, SnS₂ and SnS (for the films obtained at Ts = 250 and 300 °C) to a SnS₂ pure phase with a hexagonal structure (for Ts ≥ 350 °C). The morphological, optical, and electrical properties of SnS₂ films are greatly improved by temperature increases too, especially for the film obtained at 450 °C. This suggests that there are opportunities for further efficiency by using the as-deposited SnS₂ thin film at 450 °C.

Abstract: Praseodymium (Pr) doped (0.1 to 6 wt. %) nanostructured SnO₂ thin films are prepared via nebulizer assisted spray deposition process at a deposition temperature of 320 °C. The analyses show that the films grow in (110), (301) and (310) preferred orientations. The fabricated sensing films are exposed to LPG at 500 ppm concentration and at different operating temperatures. In 500 ppm of LPG, at an operating temperature of 350 °C, a commendable sensor response of 99 % with fast response time of 9 s and recovery time of 11 s is shown by 1wt.% Pr doped film, which is appreciable compared to pristine SnO₂ film. The sensor response reduces at lower operating temperatures. Microstructural investigations justify the gas sensing performance of 1 wt.% Pr doped SnO₂ thin film. Raman and photoluminescence studies give an insight into oxygen vacancies and trapped states that have a crucial influence on gas sensing.

Abstract: Titanium dioxide (TiO₂) has been exploited extensively as it shows remarkable performance in photocatalytic applications. TiO₂ thin films can be deposited onto window glass which is workable for self-cleaning applications. In this article, we have studied the role of substrate temperature for spray pyrolysis (SP) of TiO₂ thin films for studying self-cleaning applications. For thin film deposition, TiO₂ sol is prepared by the sol-gel synthesis technique. The samples are deposited at room temperature and 250 °C, respectively. The samples are characterized via Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), and UV-Vis spectroscopy to determine the morphology, surface roughness, and optical properties of the thin films. SEM and AFM results show that samples deposited at 250 °C (pre-heated samples) have uniform size distribution, and defined grain boundaries, respectively. The results also show that the pre-heated sample is highly transparent in the visible region of the solar spectrum when analyzed by the steady-state UV-Vis spectrophotometer. The wettability of the prepared thin films is measured, and the results show that the pre-heated sample shows a hydrophilic character. The self-cleaning property of prepared thin films is evaluated by the photodegradation of Rhodamine B dye. It is observed that the pre-heated substrates show better photoactivity in presence of UV light irradiation. Hence, due to their hydrophilic nature and better photoactivity, these pre-heated thin films deposited by spray pyrolysis can be employed as efficient coatings for self-cleaning glass applications.

Abstract: Titanium dioxide and gold nanoparticles were synthesized using an environmentally friendly method to deposit undoped and Au-doped TiO₂ thin films on silicon and glass substrates via the spray pyrolysis technique. The effect of the Au nanoparticles concentrations on structural, morphological, and hydrogen sulfide (H₂S) gas sensing characteristics of TiO₂ thin films were investigated. An X-ray diffraction pattern confirmed the polycrystalline structure of the films deposited on glass and Si substrates with a dominant rutile phase and the formation of additional mixed-phases of Ti-Au bonding. According to a Field Emission-Scanning Electron Microscopy investigation, the cluster size ranged from 20 to 180 nm depending on the concentration of AuNPs. The sensing response of the prepared films was tested against H₂S at different operating temperatures. The effect of growing a mixture of titanium-gold phases as a suitable catalyst for hydrogen sulfide sensitivity is also discussed.

Abstract: Ultrasonic Spray Pyrolysis (USP) technique was used to prepare undoped and (2, 4, 6 and 10 at. %) Zn-doped iron oxide (Fe_xO_y:Zn) thin films for use in photocatalytic applications. The effect of Zn ion substitution on structural, optical, and electrical properties was studied. The X-ray diffraction patterns showed that there are two different phases of iron oxide, a hematite phase (α‑Fe₂O₃) and a magnetite phase (Fe₃O₄) that crystallized in the prepared samples. The nominal fractions of α‑Fe₂O₃ and Fe₃O₄ phases changed from 74 % to 42 % for the hematite phase and from 26 % to 58 % for the magnetite phase and this confirmed that the Zn doping favored the growth of Fe₃O₄ phase. The crystallite size decreased from 15.43 nm to 8.99 nm, while the micro-strain changed from 0.0056 to 0.0215 and the dislocation density from 0.0099 nm^‑2 to 0.0639 nm^‑2. The unit cell parameters were also improved when the doping rate was changed. Optical measurements showed that the energy gap decreased from 2.26 eV to 2.16 eV, the film thickness changed from 569 nm to 479 nm while the refractive index increased from 2.99 to 3.51 and the Urbach energy from 544 meV to 558 meV. Electrical measurements performed by the two-point probe method showed that the electrical conductivity increased directly with increasing Zn concentration reaching 18.5 10^‑15 (Ω.cm)^‑1 with 10 at. % Zn concentration. The variation of the electrical conductivity curves versus the sample heating temperature as well as the activation energy showed a semiconductor behavior of the films. Zinc doped iron oxide thin films exhibit 51.85 % photocatalytic degradation efficiency for methyl green organic dye.

Abstract: Thin film of cobalt ferrite has been deposited on glass substrate by a chemical spray pyrolysis technique using methanol solutions at 400^◦C substrate temperature. The uniformly deposited thin film were annealed at 500 ^◦C and studied their structural, infrared and optical properties using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and UV-Vis spectroscopy (UV-Vis), respectively. The X-ray diffraction patterns revealed single phase cubic spinel structure with space group Fd-3m. The fundamental absorption bands related to octahedral and tetrahedral sites were confirmed by Fourier-transform infrared spectroscopy (FTIR) spectrum.The formation of cubic spinel crystal structure of the CoFe₂O₄ thin filmwere confirmed from exhibited strong absorption peaks around 530.21 and 451.48 cm⁻¹ by FT-IR spectra.The optical properties of the deposited thin film were studied by an absorbance spectrum found at 315 nm. The value of energy bandgap (2.4 eV) wasinvestigated by Tauc plot.The obtained results indicate the fabricated thin film is promising material for various applications.

Abstract: In the present work, pure copper ferrite (CuFe₂O₄) thin film has been grown on clean glass substrate by using the spray pyrolysis deposition technique. All the necessary parameters were optimized before the deposition. The deposited thin film was annealed at 500°C for 4 h and then cooled to room temperature. X-ray diffraction (XRD) technique was used to study the phase purity and crystal structure of the sample formed on the thin film. The analysis of the X-ray diffraction pattern reveals the formation of a single-phase cubic spinel structure. The lattice constant and other structural parameters calculated from XRD data are in good agreement with the reported data.