Effect of acetic acid on ZnO:In transparent conductive oxide prepared by ultrasonic spray pyrolysis

Undoped and indium doped zinc oxide (ZnO) transparent conductive oxide were prepared by a low-cost Ultrasonic Spray Pyrolysis. The influence of acetic acid on properties of the ZnO thin films was investigated. The complex formed by [CH₃COO⁻] and [Zn²⁺] in precursor solution was better for the growth of ZnO film. The acetic acid added in precursor solution can supply [CH₃COO⁻] for both [Zn²⁺] and [In³⁺] to form complexes. That made the [Zn²⁺] and [In³⁺] have similar statement, which can promote the indium doping in the ZnO films. The surface morphology, structural and electrical properties of the ZnO thin films were influenced by the acetic acid adding. The total transmittance of the ZnO thin films is above 80% in the wide wavelength region from 400 nm to 2000 nm.     

Characterization of ultrasonic spray pyrolysed ruthenium oxide thin films

The ultrasonic spray pyrolysis (USP) technique was employed to deposit ruthenium oxide thin films. The films were prepared at 190°C substrate temperature and further annealed at 350°C for 30 min in air. The films were 0.22 μ thick and black grey in color. The structural, compositional and optical properties of ruthenium oxide thin films are reported. Contactless transient photoconductivity measurement was carried out to calculate the decay time of excess charge carriers in ruthenium oxide thin films.     

Anatase-rutile transformation through high-temperature annealing of titania films produced by ultrasonic spray pyrolysis

Titanium dioxide films were prepared by ultrasonic spray pyrolysis on (0001) α-quartz substrates at 400 °C and/or annealed in air at 600°, 800°, or 1000 °C. The as-deposited films at 400 °C (50 nm grains) and annealed at 600 °C (100 nm grains) showed single-phase anatase of high transparency in the visible region. Films annealed at 800 °C and 1000 °C showed mixed-phase anatase (100 nm grains) plus rutile (700 nm agglomerates) and pure rutile, (700 nm grains), respectively. Raman and X-ray data indicate the presence of residual stress in the films, which may arise from contamination, silicon diffusion into the films, and/or oxygen deficiency.     

Gas-chromism in ultrasonic spray pyrolyzed tungsten oxide thin films

A simple and inexpensive ultrasonic spray pyrolysis (USP) technique has been employed to deposit tungsten oxide (WO₃) thin films by spraying 2.0 mM aqueous ammonium metatungstate solution onto the amorphous glass substrates kept at 250°C. The films were further annealed at 400°C for 4 h in air. X-ray diffraction (XRD) technique was used to determine the crystallinity and to identify the WO₃ phases. It was found that the films were sub-stoichiometric, WO_3-z. To study gas-induced properties, a catalyzing layer of platinum (Pt) was sputtered onto it. The gas-induced electrical and optical properties of Pt/WO₃/glass samples were studied and results reported. It was found that electrical resistivity decreased by a factor of 10 within 2 min and stabilized after 15 min, after H₂ gas exposure. Similarly the optical transmittance of the samples attenuated from 55% to 10% within 15–20 min. The reversible changes in electrical resistivity and optical transmittance were observed when the samples were exposed to oxygen. The response times and sensitivity of the samples were estimated.     

Temperature dependence of Fluorine-doped tin oxide films produced by ultrasonic spray pyrolysis

Fluorine-doped tin oxide (FTO) films were prepared at different substrate temperatures by ultrasonic spray pyrolysis technique on glass substrates. Among F-doped tin oxide films, the lowest resistivitiy was found to be 6.2 × 10^− 4 Ω-cm for a doping percentage of 50 mol% of fluorine in 0.5 M solution, deposited at 400 °C. Hall coefficient analyses and secondary ion mass spectrometry (SIMS) measured the electron carrier concentration that varies from 3.52 × 10²⁰ cm^− 3 to 6.21 × 10²⁰ cm^− 3 with increasing fluorine content from 4.6 × 10²⁰ cm^− 3 to 7.2 × 10²⁰ cm^− 3 in FTO films deposited on various temperatures. Deposition temperature on FTO films has been optimized for achieving a minimum resistivity and maximum optical transmittance.     

超声喷雾热解法制备ZnO薄膜及性能研究

以醋酸锌水溶液为前驱体溶液,使用自制的超声喷雾热解系统在玻璃基板上制备得到了ZnO薄膜.经X射线衍射(XRD),扫描电镜(SEM)分析得到ZnO薄膜的晶体结构和微观形貌.测试结果表明,ZnO薄膜为六角纤锌矿结构,在450～500℃下制备的薄膜显示出良好的结晶性能,并且沿(002)晶面择优取向生长,薄膜具有优良的均匀性和致密性.同时,制备得到的薄膜在可见光区也表现出80%以上的高透过率.     

Single step synthesis of indium tin oxide by ultrasonic spray and microwave assisted pyrolysis

Ultrafine indium tin oxide (ITO) powders were successfully synthesised by the combined methods of ultrasonic spray and microwave assisted pyrolysis, which is a single step, facile, rapid and continuous method without post-heating treatment. Crystallinity, morphology and microstructure of the samples were investigated by X-ray diffractometer, scanning electron microscope, transmission electron microscope, energy dispersive X-ray spectroscope, selected area electron diffraction pattern and laser grain size analyser. Results indicate that pure solid solution ITO ultrafine powders with homogeneous and narrow size distribution, highly dense and smooth surface morphology can be obtained under optimum conditions. Each uniform spherical particle consisted of many smaller crystallites with diameter of <10 nm.     

Synthesis and characterization of carbon nanotubes via ultrasonic spray pyrolysis method on zeolite

Ultrasonic spray pyrolysis method for the synthesis of carbon nanotubes (CNTs) has been investigated with zeolite supporting material. Single wall carbon nanotubes (SWCNTs) were obtained at 850 °C in nitrogen environment. Such deposition system makes it possible to grow CNTs without reducing agent at atmospheric pressure in a simple setup. Iron and cobalt acetate were used as catalyst and ethanol as carbon source for the synthesis of CNTs. Results show that nature of zeolite and cobalt concentration play important roles for SWCNTs production. Interestingly, we notice that in catalyst particles of sharp shape, nucleation of a nanotubes cap occurs dominantly in the forward direction.     

Synthesis of mixed-phase titania films by low-temperature ultrasonic spray pyrolysis

Fully dense TiO₂ films with (1) mixed-phase rutile and anatase and (2) anatase (sole phase) were deposited on fused quartz substrates by ultrasonic spray pyrolysis at nominally 400 °C. The presence and absence of insulation around the entrainment pathway traversing 20 cm above the substrate/hot plate were investigated (174 °C vs 122 °C). The thick films were assessed in terms of mineralogies (qualitative and quantitative), microstructures (topography, thickness and grain size), and visible light transmission (optical and microstructural considerations). With insulation, opaque mixed anatase (∼ 30 vol.%; < 50 nm) and rutile (∼ 70 vol.%; ∼ 1 μm) were observed; without insulation, only transparent anatase (< 50 nm) was observed.     

Low cost synthesis of high-Tc superconducting films on metallic substrates via ultrasonic spray pyrolysis

Ultrasonic spray pyrolysis technique has been used to deposit both in situ and ex situ high temperature superconducting films (HTSC) of Y₁Ba₂Cu₃O_x(YBCO) and Bi₂Sr₂CaCu₂O_x (BSCCO) compounds over various substrates. Nitrate precursor solutions are used to deposit films of ∼10 μm thickness. Both low temperature spray with substrate temperature T_s < 500 °C and high temperature deposition with T_s = 550-900 °C are carried out. Superconducting properties of these films are observed to vary with various parameters such as concentration of spray solution, deposition temperature and nature of substrate and annealing process. Best quality films show T_c (R = 0) of 89 K and J_c of ∼4 × 10⁴ A/cm² at 77 K and ∼ 10⁵ A/cm² at 20 K. X-ray diffraction pattern reveals that the films are textured along c-axis. Successful attempt has been made to deposit in situ superconducting films over polycrystalline Ag for coated conductor applications. Various deposition and annealing conditions are optimized to control the diffusion of Ag from substrate to film, which otherwise can segregate into the grain boundaries and make the films non-superconducting.     

Optical and electrical properties of zinc oxide films prepared by spray pyrolysis

Zinc oxide thin films were prepared on glass substrates from an aqueous solution of zinc acetate by spray pyrolysis. These films were characterized using X-ray diffraction, scanning electron microscopy and optical transmission. The films were highly transparent to the visible radiation and electrically conductive. Films deposited at optimum conditions exhibited a resistivity of 3·15×10⁻³ Ωm along with a transmittance of 98% at 550 nm.     

Comparison of structural and photoluminescence properties of ZnO thin films grown by pulsed laser deposition and ultrasonic spray pyrolysis

ZnO thin films have been deposited by pulsed laser deposition (PLD) and ultrasonic spray pyrolysis (USP) method, respectively. X-ray diffraction and transmission electron microscopy characterizations indicate that ZnO film grown by PLD exhibits better crystallinity than that grown by USP. Photoluminescence spectra show that the near-band edge ultraviolet emission of film grown by PLD is narrower and shifts to higher energy, compared with that of film grown by USP. In the visible range, ZnO film grown by PLD exhibits four local level emission centered at 470 nm, 486 nm, 544 nm, and 613 nm, respectively, while the film grown by USP only presents a weak broad band emission centered at 502 nm. Hall measurement shows higher carrier density and lower hall mobility in ZnO film grown by PLD than that in film grown by USP. The higher density of intrinsic defects as well as higher crystallintiy is considered to account for the difference of photoluminescence in ZnO film grown by PLD with that in film grown by USP.     

Low substrate temperature synthesis of carbon nanowalls by ultrasonic spray pyrolysis

In this paper, we report the synthesis of two-dimensional wall like carbon nanostructures (i.e. carbon nanowalls) by ultrasonic spray pyrolysis of ethanol and fullerene mixture. At higher temperature carbon nanofibers were formed on the substrate placed at the center of the reactor tube, whereas carbon nanowalls were observed on the substrate placed downstream of the tube below 100 °C. Spaces between the nanowalls changed with distance of the substrates from the furnace. Qualitative analysis of materials was performed using scanning electron microscopy, transmission electron microscopy and Raman spectroscopy.     

喷雾热解法制备掺氟氧化锡导电玻璃及其性能

采用喷雾热解法,以四氯化锡和氟化铵为原料、喷瓶为雾化装置,在载玻片上制得氟掺杂二氧化锡(FTO)透明导电薄膜。运用XRD、SEM、紫外-可见分光光度计和四探针测试仪分别对薄膜进行了表征。研究了喷涂次数、衬底温度、前体浓度、掺杂浓度和醇水比对FTO薄膜光电性能的影响。结果表明,当衬底温度为500℃,SnCl4.5H2O浓度为0.81mol/L,NH4F浓度为0.1mol/L,醇水比为8:2,喷涂100次时,薄膜的光电性能较好,其方块电阻为13Ω/□,平均透光率为79%。     

Effect of pyrolysis temperature on structural,microstructural and optical properties of nanocrystalline ZnO powders synthesised by ultrasonic spray pyrolysis technique

In this article, we report on the effect of pyrolysis temperature on structural, microstructural and optical properties of nanocrystalline ZnO powder synthesised by ultrasonic spray pyrolysis (USP) technique. Powder samples P1, P2 and P3 were prepared at various pyrolysis temperatures (temperature of 2nd zone) of 973, 1073 and 1273?K, respectively. Phases were identified and crystallite sizes were calculated from X-ray diffraction (XRD) diagrams. The morphology and size of ZnO nanocrystallites associated with nanopowder were studied using transmission electron micrograph (TEM). It revealed that the powder consisted of crystallites ranging in size from 9 to 20?nm. These values were matching with the crystallite sizes calculated from XRD. Both XRD and TEM studies of ZnO nanopowders showed that the crystallite sizes increased with an increase in the pyrolysis temperature. The synthesised nanopowders exhibited direct band gap (E _g) in the range 3.37–3.40?eV.     

One-pot synthesis of hematite-alumina hollow sphere composite by ultrasonic spray pyrolysis technique with high adsorption capacity toward PAHs

A hybrid nanocomposite of alumina and hematite was synthesized by ultrasonic spray pyrolysis technique. The study of microscopic images, mapping analysis, and XRD patterns revealed that the Al₂O₃ – Fe₂O₃ nanocomposite was composed of separated spherical particles with a thin layer ball-shaped structure that metal oxides are uniformly distributed in the wall of hollow sphere particles, led to a coherent and monotonous construction. A series of coefficients of equilibrium sorption of polycyclic aromatic hydrocarbons (PAHs) as hazardous materials were measured on the prepared composite material in a batch technique. The free or pure Al₂O₃ or Fe₂O₃ showed negligible removal efficiency for the mentioned analytes. The various significant variables, such as initial analyte concentration, solution pH, adsorbent dose, and contact time to remove analyte, were studied in the aqueous solutions. Adsorption data were modeled to Langmuir, Freundlich, and Temkin isotherms, and a good correlation found in the case of Langmuir isotherm and adsorption capacity for anthracene, phenanthrene, and naphthalene were 370, 333, and 322 mg g^?1, respectively. Investigation of the kinetic models proved a pseudo-second-order, and the prepared adsorbent can be reused more than 7 times without a significant decrease of adsorption performance.     

Substrate temperature influence on ZnS thin films prepared by ultrasonic spray

ZnS thin films were deposited by ultrasonic spray technique. The starting solution is a mixture of 0.1 M zinc chloride as source of Zn and 0.05 M thiourea as source of S. The glass substrate temperature was varied in the range of 250 °C-400 °C to investigate the influence of substrate temperature on the structure, chemical composition and optical properties of ZnS films. The DRX analyses indicated that ZnS films have nanocrystalline hexagonal structure with (002) preferential orientation and grain size varied from 20 to 50 nm, increasing with substrate temperature. The optical films characterization was carried out by the UV-visible transmission. The optical gap and films disorder were deduced from the absorption spectra and the refractive indices of the films were determined by ellipsometric measurements. It is shown that the obtained films are generally composed of ZnO and ZnS phases with varied proportion, while at deposition temperature of 400 °C, they are near stoichiometric ZnS.     

Recent progress in electrode materials produced by spray pyrolysis for next-generation lithium ion batteries

We review the effect that various structures and composites synthesized by spray pyrolysis have on the electrochemical performance of next-generation electrodes for medium and large lithium ion batteries. The morphologies of electrode particles in particular have a strong influence on the capacity, power, safety, and cycle life. Recent progress in improving the electrochemical performance of electrodes is provided with a particular focus on electrodes composed of nanoparticles, core–shell or yolk–shell structures, and carbon-based composites. Finally, we propose a direction for future research for high-performance lithium ion batteries incorporating fabrication by spray pyrolysis.     

One step synthesis process for fabricating NiFe2O4 nanoparticle loaded porous carbon spheres by ultrasonic spray pyrolysis

In the present work, the porous hollow carbon spheres loaded with NiFe₂O₄ nanoparticles have been successfully prepared via ultrasonic spray pyrolysis technique at 700?°C and the associated formation mechanism has been studied. The as-prepared NiFe₂O₄/carbon microspheres with the diameter of about 3–5?µm and the specific surface area of 236.6889?m²?g^?1 exhibit good monodispersity and an abundance of mesopores of about 40?nm size. Notably, the 20?nm NiFe₂O₄ nanoparticles are encapsulated by carbon microspheres and disperse homogeneously inside the carbon matrix. We could tune the relative content of ferrite and carbon sphere via adjusting the composition of the solution used for synthesis and the carbonization temperature. Consequently, some interesting properties can be obtained by combining the magnetic NiFe₂O₄ nano powder and the electrically conductive porous carbon, which renders the resulting composite suitable for promising applications in electromagnetic wave absorption, treatment of polluted water, catalyst design, energy storage, batteries and so on.     

Evaluation of photocatalysis of Au supported ZnO prepared by the spray pyrolysis method

Environmental pollution by organic dyes used in industry is a serious problem in developing countries. Environmentally friendly treatment methods are being studied because conventional methods require chemical or additional decomposition treatment. In particular, oxidation via a photocatalyst is a promising alternative due to its chemical and physical stabilities and low cost. However, electron-hole recombination limits the photocatalytic activity in semiconductor photocatalysts such as ZnO and TiO₂. This study investigates control of electron-hole recombination of the photocatalyst by loading Au on ZnO (Au/ZnO). Using the Ultrasonic Spray Pyrolysis (USP) method, Au/ZnO particle generation is easily achieved under various conditions. XRD analysis confirms the crystal peaks of ZnO and Au. The EDX mapping and STEM images of the particles show that the Au crystals are well dispersed in the inner and outer portions of ZnO. The photocatalytic decomposition rate of organic dye (Rhodamine-B) is faster than that of ZnO in all Au/ZnO particles, and the best photocatalytic activity occurs in particles with 0.1 mass% Au supported on ZnO particles. In addition, optimal photolysis activity occurs in 100 mL of 5 mg/L RhB aqueous solution and 10 mg dose of Au/ZnO particles.