This study unveils the outcomes of fabricating and characterizing SnO2 thin films through ultrasonic spray pyrolysis. Also, it focuses on the effect of manipulating flow rates on their structural, ...optical, and electrical characteristics. Structural analysis revealed that the films exhibited a tetragonal rutile structure and (200) crystallographic planes become preferential as the flow rate increases. Crystallite size and lattice strain were calculated using the Debye-Scherrer and Williamson-Hall methods, demonstrating that higher the flow rate resulted in larger crystallite sizes and reduced lattice strain. SEM images showed that all films have uniform and consistent film thickness and grain size enlarged with the solution flow rate as well. The films exhibited high optical transparency (>80%) in the visible spectrum, making them suitable for transparent conductive applications. The band gap of the films decreased gradually with flow rates, and the Urbach energy slightly increased. Hall effect measurements revealed higher flow rates resulted in lower sheet resistance (lowest is 1.32 × 102 Ω/sq) and higher carrier mobility (highest is 22.12 cm2/V.s), indicating improved electrical properties. These findings offer valuable perspectives for forthcoming researches.
•(200) crystallographic plane becomes preferential as the flow rate increases.•A very consistent and uniform film thickness was achieved.•Film thickness increases with higher solution flow rates, leading to larger grains.•Optical transmittance exceeding 80% in the visible spectrum, is required for TCOs.•Higher flow rates result in lower sheet resistance and higher carrier mobility.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Recently, photoelectrochemical conversion (PEC) of water into fuel is attracting great attention of researchers due to its outstanding benefits. Herein, a systematic study on PEC of water using ...CuFe2O4/ α–Fe2O3 composite thin films is presented. CuFe2O4/ α–Fe2O3 composite thin films were deposited on two different substrates; (1) planner FTO glass and (2) 3-dimensional nanospike (NSP). The films on both substrates were characterized and tested as anode material for photoelectrochemical water splitting reaction. During PEC studies, it was observed that the ratio between two components of composite is crucial and highest PEC activity results were achieved by 1:1 component ratio (CF-1) of CuFe2O4 and α–Fe2O3. The CF-1 ratio sample deposited on planar FTO substrate provided a photocurrent density of 1.22 mA/cm2 at 1.23 V RHE which is 1.9 times higher than bare α–Fe2O3 sample. A significant PEC activity outperformance was observed when CF-1 ratio composite thin films were deposited on 3D NSP. The highest photocurrent density of 2.26 mA/cm2 at 1.23 V RHE was achieved for 3D NSP sample which is around 3.6 times higher than photocurrent density generated by α–Fe2O3 thin film only. The higher photocurrent densities of 3D nanostructured devices compared to planar one are attributed to the enhanced light trapping and increased surface area for photoelectrochemical water oxidation on the surface. The difference between valence and conduction bands of CuFe2O4 and α–Fe2O3 allows better separation of photogenerated electrons and holes at the CuFe2O4/ α–Fe2O3 interface which makes it more active for photoelectrochemical water splitting.
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IJS, KILJ, NUK, PNG, UL, UM
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•Ru-doped MoO2 was prepared by ultrasonic spray pyrolysis in one step.•High-dispersed ruthenium had strong interactions with MoO2.•A high concentration of ruthenium on the MoO2 ...surface enhanced hydrogen evolution activity.•Ru-MoO2 showed excellent mass activity in all pH range.
Platinum (Pt)-based catalyst is a state-of-the-art catalyst for hydrogen evolution reaction (HER) of electrochemical water splitting. Nevertheless, to minimize the overall water electrolysis cost, a new catalyst must be developed. Ruthenium (Ru)-based catalyst has recently been found to be an efficient HER catalyst in all pH ranges of electrolytes. However, they demonstrated lower HER activity than Pt-based catalysts. Hence, to maximize the electrocatalytic activity, a highly dispersed Ru-based catalyst should be studied while maintaining a high-loading amount. This study prepares a high-dispersed Ru catalyst using the ultrasonic spray pyrolysis (USP) process on a molybdenum dioxide (MoO2) support. The USP process enabled the dispersion of Ru on MoO2 with high-loading (9 wt%) and dispersion. The high dispersion of Ru and the strong interaction between Ru and MoO2 improved the HER activity.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this study, the optimization of the deposition temperature, which directly affects the crystallinity, morphology, and electrical conductivity of SnO2 films deposited onto Corning Eagle XG glass ...substrates using the ultrasonic spray pyrolysis technique, was investigated to tailor their physical properties for various applications. Structural analyses revealed that the films had a tetragonal rutile structure, and while films deposited at lower temperatures exhibited a higher prevalence of (200) oriented planes, yet this decreased with an increase in deposition temperature. Morphological analyses showed that the films consisted of grains with octahedral shapes, and films deposited at lower temperatures were found to be more compact. The films had bandgap energy ranges between 3.96 eV and 4.02 eV. Hall effect measurements revealed that not only the carrier concentration decreased from 4.52 × 1019 cm−3 to 0.80 × 1019 cm−3, but the mobility also decreased from 23.32 cm2/Vs to 12.85 cm2/Vs. Among all the films, it was noted that the films deposited at 350 °C had the highest figure of merit which is 12.3 × 10−4 Ω−1. It can be concluded that the changes underlying these variations are associated with structural and morphological changes depending on the substrate temperature. Also, significant results have been attained in applications where precise control over crystal structure and surface morphology is crucial.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
MISIM (metal-insulator-semiconductor-insulator-metal) structures of alternating current thin film electroluminescent (ACTFEL) devices were deposited on ATO/glass substrates by the ultrasonic spray ...pyrolysis technique. Zirconium oxide and terbium doped zinc sulfide were used as dielectric and semiconductor phosphor layers, respectively. A focused ion beam equipment was used to prepare a lamella of the MISIM structure, for cross-sectional scanning electron microscopy analysis in the STEM mode. Chemical analysis by energy-dispersive X-ray spectroscopy (EDS) elemental maps was also made for the identification of the distribution of the elements through the layers composing the MISIM structure. Characteristic Tb3+ emission bands due the 5D4 ->7FJ transitions were obtained by AC voltage application at 10 kHz with the main peak centered at 542 nm. An increase in the electroluminescent intensity and a shift of the CIE coordinates toward a purer green color with increasing the applied voltage was observed. The threshold voltage of these green electroluminescent devices was 46 Vrms, and a luminance up to 41 cd/m2 was obtained for the maximum applied voltage of 76.9 Vrms.
•MISIM devices with green electroluminescence fabricated by ultrasonic spray pyrolysis.•The color purity of the green EL devices changes with the applied voltage.•Luminance up to 41 Cd/m2 is achieved for an operation voltage of 76 V.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this study, highly transparent conducting fluorine-doped tin oxide (FTO) electrodes were fabricated using the horizontal ultrasonic spray pyrolysis deposition. In order to improve their ...transparent conducting performances, we carried out oxygen activation by adjusting the ratio of O2/(O2+N2) in the carrier gas (0%, 20%, and 50%) used during the deposition process. The oxygen activation on the FTO electrodes accelerated the substitution concentration of F (FO •) into the oxygen sites in the FTO electrode while the oxygen vacancy (VO • •) concentration was reduced. In addition, due to growth of pyramid-shaped crystallites with (200) preferred orientations, this oxygen activation caused the formation of a uniform surface structure. As a result, compared to others, the FTO electrode prepared at 50% O2 showed excellent electrical and optical properties (sheet resistance of ∼4.0 ± 0.14 Ω/□, optical transmittance of ∼85.3%, and figure of merit of ∼5.09 ± 0.19 × 10–2 Ω–1). This led to a superb photoconversion efficiency (∼7.03 ± 0.20%) as a result of the improved short-circuit current density. The photovoltaic performance improvement can be defined by the decreased sheet resistance of FTO used as a transparent conducting electrode in dye-sensitized solar cells (DSSCs), which is due to the combined effect of the high carrier concentration by the improved FO • concentration on the FTO electrodes and the fasted Hall mobility by the formation of a uniform FTO surface structure and distortion relaxation on the FTO lattices resulting from the reduced VO • • • concentration.
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IJS, KILJ, NUK, PNG, UL, UM
Molybdates are inorganic materials with great potential in white phosphors application, being an alternative to traditional lighting sources. In this study, we report the synthesis and ...characterization of Mg 1-x Sr x MoO 4 (x = 0, 0.25, 0.50, 0.75, and 1) powders with white light-emitting properties. Using X-ray diffraction, the formation of the monoclinic β-MgMoO 4 phase was observed for x = 0 and the formation of the tetragonal scheelite phase of SrMoO4 was observed for x = 1. The formation of a heterostructure composed of both phases was found for compositions with x = 0.25, 0.50 and 0.75. Scanning electron microscopy images showed that the Mg 1-x Sr x MoO 4 particles exhibit a spherical morphology formed by several primary nanoparticles. Raman scattering spectroscopy enabled the accurate identification of the Raman modes for different compositions and their assignment to either the SrMoO 4 or β-MgMoO 4 modes. The bandgap energies were determined to fluctuate between 4.25 eV and 4.44 eV, being influenced by the degree of structural disorder. The photoluminescence emission spectra of the nanoparticles showed neutral- and cool-white emission with high-quality white light (CRI > 80%). The samples synthesized with x ≤ 0.50 are potential materials for the application in LED lamps (6500 K) and pure white-light sources (5500 K).
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this study, Ba1−xZnxMoO4 (x = 0, 0.25, 0.5, 0.75 and 1) microspheres were the first time described in the literature the by ultrasonic spray pyrolysis method. Powders were characterized by X-ray ...diffraction (XRD), scanning electronic microscopy (SEM-FEG) and UV–visible and Photoluminescence (PL) spectroscopies. The XRD patterns showed that the samples with x = 0 and x = 1 displayed pure tetragonal and triclinic structures, respectively. On the other hand, samples with x = 0.25, 0.5 and 0.75 revealed the formation of tetragonal/triclinic heterojunction structure. The SEM-FEG images showed that the Ba1−xZnxMoO4 particles present the spherical morphology with the decrease of particle sizes when the value of “x” increase. The gap energies vary between 4.56eV and 4.17eV, being influenced by the degree of structural order-disorder. The PL emission spectra of the samples showed a broad band behavior with emission intensity predominant in the orange-red region and of a lower intensity in the blue-green region. The chromaticity coordinates x and y showed that the samples with x ≤ 0.75 present emission in orange, while the samples with x = 1 showed emission in white.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The HAp (hydroxyapatite) excellent ion exchange resin and has adsorption properties of heavy metals and organic materials. It is used as an adsorption material and as an organic drug-delivery ...material due to these characteristics, that are essentially controlled the specific surface area. In this paper, the specific surface area was controlled by adding polymers of polyvinylpyrrolidone (PVP), polystyrene beads (PSB), and polyethylene glycol (PEG). Through the USP process, the HAp powder is able to synthesize into the spherical shape, specific surface area, and pore were controlled by the properties of the polymers.
