Spray Deposition Method Research Articles

Evolution of the optical response in a nanostructured fluorine doped zinc oxide thin film

We measured a strong two-photon absorption effect in a fluorine doped ZnO thin solid film prepared by a simple and low-cost chemical spray deposition method. We carry out our transmittance experiments with a near-resonant excitation with a single beam at 445 nm wavelength. By monitoring the change in temperature originated by the optical irradiation we were able to detect the participation of an important nonlinear optical absorption in the interaction. The effect of the aging time of the starting solution on the modification of photoluminescence (PL) and optical absorption exhibited by the sample was observed. We estimate that the formation of the nanostructured morphology of the thin solid films generates an enhancement in the near-resonant two-photon absorptive effect and in the PL of the zinc oxide.

Characterization of LSCF-Based Composite and LSCF as Cathodes for Intermediate Temperature SOFCs

The (La0.60Sr0.40)(Co0.20Fe0.80)O3-δ - LSCF, (Ce0.90Gd0.10)O1.95 - CGO composites and LSCF were deposited by wet powder spraying deposition method for the purpose of investigating their potential use in Intermediate Temperature Solid Oxide Fuel Cells. The interlayers are necessary between CGO electrolytes and LSCF cathodes in order to improve the performance of these materials. LSCF particles synthesized by citrate technique were calcined at 900 °C for 4 h and, their LSCF-CGO composites and LSCF suspensions deposited on CGO substrate and, sintered in 1100 °C for 1 h, were formed pseudo-perovskite. The ceramics materials were analyzed by X-ray diffraction (XRD) and chemical composition of different half-cells layers by scanning electron microscope with energy dispersive (SEM-EDS). The results are in agreement with the literature and indicate that route studied is adequate for crystal structures formation compatible with films the 35 µm thick total for study of conductivity between the cathode and the electrolyte.

Thermally stable and transparent superhydrophobic sol–gel coatings by spray method

A facile method was developed for the fabrication of the methyltriethoxysilane based transparent and superhydrophobic coating on glass substrates. The transparent and hydrophobic coatings were deposited on the glass substrates, using spray deposition method followed by surface modification process. A spray deposition method generates hierarchical morphology and post surface modification with monofunctional trimethylchlorosilane decreases the surface free energy of coating. These combined effects of synthesis produces bio-inspired superhydrophobic surface. The deposited coating surface shows high optical transparency, micro-nano scale hierarchical structures, improved hydrophobic thermal stability, static water contact angle of about 167° ± 1°, low sliding angle about 2° ± 1° and stable superhydrophobic nature. This paper provides the very simple sol–gel approach to the fabrication of optically transparent, thermally stable superhydrophobic coating on glass substrates. This fabrication strategy may easily extend to the industrial scale up and high-technology fields.

Hydrogen transport properties of palladium film prepared by colloidal spray deposition

Palladium films were fabricated by a novel colloidal spray deposition method. Dense, crack-free Pd films with thickness of 5–11 μm were successfully fabricated on porous yttria-stabilized zirconia (YSZ) substrates having pore size of 3–7 μm. Scanning electron microscopy showed that the film has uniform thickness and is well bonded to the substrate. The surface of the Pd film is composed of well-crystallized plate-like grains with diameter of 2–4 μm and has a rough texture. The X-ray diffraction pattern of the as-sintered Pd film indicates (111) preferred crystal orientation. The hydrogen permeation properties of the films were investigated at temperatures of 330–530 °C using 90% H2/balance He and N2 as feed and sweep gases, respectively. The hydrogen permeation of the supported Pd films with thickness of 5–11 μm was limited by both the diffusion of hydrogen through the metal bulk and the gas-phase transport through the support. The resistance of the gas-phase transport through the substrate was lowered significantly by reducing the thickness of the substrate.

Growth and conductivity enhancement of N-doped ZnO nanorod arrays

A simple two-step process was developed for growing the nitrogen-doped ZnO (NZO) nanorod arrays on glass substrates. ZnO particles serve as a seed layer deposited by the electrostatic spray deposition method for the growth of NZO nanorods in aqueous solution. FE-SEM images revealed that nanorods have approximately uniform length distribution with hexagon end planes and grow vertically along the c-axis, which was also confirmed by X-rays diffraction. In addition, NZO nanorods had an average diameter of 140±20nm and an average length of 1.2 to 2.7μm with a wurtzite-type structure of ZnO. N doping had no prominent effect on the structure and crystal orientation, but it helps to increase the length and reduction in the diameter of nanorods. Moreover, electrical resistivity was found to decrease first and then increase with further nitrogen doping due to the decrease of mobility and increase of carrier concentration. Also the transmittance increased initially, but at higher nitrogen contents it decreased. Annealing the nanorods imparts no effect on the morphology, but there was a significant decrease in electrical resistivity due to the formation of oxygen vacancies. The realization of p-type ZnO nanorod arrays with durable and controlled transport properties is important for the fabrication of nanoscale electronic and optoelectronic devices.

High-performance low-temperature solid oxide fuel cells using thin proton-conducting electrolyte with novel cathode

We have fabricated BaCe0.8Gd0.2O3−δ (BCGO) thin films with thickness in the range of 5–10 μm over substrates composed of Ce0.8Gd0.2O1.9 (CGO)-NiO using a colloidal spray deposition method. A perovskite-type BaZr0.2Co0.4Fe0.4O3−δ (BZCFO) was employed as a novel cathode material. The performances of solid oxide fuel cells were investigated from 450 °C to 600 °C. The fuel cell with the BCGO film of 9 μm in thickness showed maximum power outputs of 237, 192, 136 and 89 mW cm−2 at 600, 550, 500 and 450 °C, respectively. The impedance measurements at open circuit conditions showed the polarization resistances of the electrode were about 0.25 and 1.00 Ω cm2 at 600 and 500 °C, respectively. The low interfacial resistances indicated that the BZCFO was a promising cathode material for low-temperature proton-conducing solid oxide fuel cells.

Fabrication of ordered bulk heterojunction organic photovoltaic cells using nanopatterning and electrohydrodynamic spray deposition methods

Organic photovoltaic cells with an ordered heterojunction (OHJ) active layer are expected to show increased performance. In the study described here, OHJ cells were fabricated using a combination of nanoimprinting and electrohydrodynamic (EHD) spray deposition methods. After an electron donor material was nanoimprinted with a PDMS stamp (valley width: 230 nm, period: 590 nm) duplicated from a Si nanomold, an electron acceptor material was deposited onto the nanoimprinted donor layer using an EHD spray deposition method. The donor-acceptor interface layer was observed by obtaining cross-sectional images with a focused ion beam (FIB) microscope. The photocurrent generation performance of the OHJ cells was evaluated with the current density-voltage curve under air mass (AM) 1.5 conditions. It was found that the surface morphology of the electron acceptor layer affected the current and voltage outputs of the photovoltaic cells. When an electron acceptor layer with a smooth thin (250 nm above the valley of the electron donor layer) surface morphology was obtained, power conversion efficiency was as high as 0.55%. The electrohydrodynamic spray deposition method used to produce OHJ photovoltaic cells provides a means for the adoption of large area, high throughput processes.

902 有機薄膜太陽電池製造におけるスプレー製膜法と噴霧条件変化による膜状態の改善(CMP加工1)

902 有機薄膜太陽電池製造におけるスプレー製膜法と噴霧条件変化による膜状態の改善(CMP加工1)

Electrostatic Spray Deposition of Highly-Crystalline TIPS Pentacene Thin Films for Fabrication of Organic Field-Effect Transistors

ABSTRACTThis paper demonstrates that electrostatic spray deposition (ESD) method is a promising solution process to fabricate highly-crystalline organic films (6,13-bis(triisopropylsilylethynyl) pentacene; TIPS pentacene) for the use in bottom-contact organic field-effect transistors (OFETs). We obtained large crystalline domains (i.e., molecularly-oriented domains) by using an o-DCB:acetone mixed solvent (1:1), and observed good transistor behavior in an OFET having the channel length of 20 μm.

静電噴霧堆積法によるCa1-xLaxMnO3+δ薄膜の作製と評価

静電噴霧堆積法によるCa1-xLaxMnO3+δ薄膜の作製と評価

Fine particle preparation and electrode property of layered-type LiNi0.4Co0.6-xTixO2

ABSTRACTLayered-type LiNi0.4Co0.6-xTixO2 (0≤x≤0.2) were prepared by conventional electrostatic spray deposition method for studying the correlation of crystal structure and electrode property. Starting materials used were LiNO3, Ni(NO3)2·6H2O, Co(NO3)2·6H2O and TiO2 nano-slurry. These materials were dissolved or dispersed in a mixture of ethanol and butyl carbitol and mixed by predefined ratio, respectively. Then, each of mixtures was sprayed and dried on the grounded reaction plate which was heated at 400 °C. Deposited powder was sintered at 700˚C for 10 hours in air atmosphere. Library of LiNi0.4Co0.6-xTixO2 (0≤x≤0.2) was indexed R-3m by powder X-ray diffraction patterns and its chemical compositions from ICP emission spectroscopy method corresponded to the initial composition conditions. From the diffracted intensity ratio of I(003)/I(104) and the structure refinement by Rietveld method, it was found that the proportion of cation mixing effect increased with increasing amount of Ti among of transition metals. And, from the observation by scanning electron microscope and the calculation by Scherrer’s method, the crystallite size decreased with increasing amount of Ti element. From the charge-discharge property of LiNi0.4Co0.6-xTixO2 (0≤x≤0.2) library, LiNi0.4Co0.5Ti0.1O2 showed better cycle behavior among the library.

Fabrication of high-performance fluorine doped–tin oxide film using flame-assisted spray deposition

A high-performance fluorine–doped tin oxide (FTO) film was fabricated by flame-assisted spray deposition method. By varying the NH 4F doping concentration, the optimal concentration was established as 8 at.%. X-ray diffractograms confirmed that the as-grown FTO film was tetragonal SnO 2. In addition, the FTO film was comprised of nano-sized grains ranging from 40 to 50 nm. The heat-treated FTO film exhibited a sheet resistance of 21.8 Ω/ with an average transmittance of 81.9% in the visible region (λ = 400–800 nm). The figures of merit shows that the prepared FTO film can be used for highly efficient dye-sensitized solar cells electrodes.

Cost-effective electrostatic-sprayed SrAl2O4:Eu2 + phosphor coatings by using salted sol–gel derived solution

3 Mol% of europium doped strontium aluminate (SrAl2O4:Eu2 + ) coatings on silicon substrates were prepared by electrostatic spray deposition method using a salted sol–gel derived solution as a starting material. As-deposited films at 100°C for 5 h were heated at 1100°C for 2 h under a reducing ambient atmosphere of 95%N2 + 5%H2. Nanocrystalline SrAl2O4 film was confirmed by surface morphological and crystallographic analyses. Monitored at 520 nm, the excitation spectrum showed a broad band from 300 ~ 500 nm and the emission intensity showed a maximum yellow peak intensity at 512 nm with a broad band from 460 ~ 610 nm.

Application of an Electro Spray Deposition (ESD) Method to Control the Pre-Tilt Angle in a Nematic LC Cell

We applied the ESD technique to form an aligned LC layer with controlled pre-tilt angle. First, a horizontally aligned film was formed on the glass substrate by coating and rubbing. Then, a material promoting vertical alignment was sprayed using the ESD method. The aligned layer consisted of very fine domains mingled with horizontally and vertically aligned part. We were able to control the pre-tilt angle in a wide range by varying the amount of sprayed solution of the aligning material.

Spray deposition method for the synthesis of supported catalysts with superior metal dispersion

We introduce a novel ‘spray deposition’ method as a continuous, reproducible, versatile, simple, and scalable method for the preparation of highly-dispersed, uniformly-sized, and sintering-resistant supported metal nanoparticles on porous supports. Instant drying of aqueous aerosol droplets containing the metal precursor (e.g. palladium nitrate) and the support (e.g. ferrierite zeolite) in a commercial bench-scale spray drier proves the key for maximizing the metal dispersion. In contrast, the much lower rates of solvent removal characteristic of dry and wet impregnation methods using classical drying or even freeze drying led to broad particle size distributions. The spray-dried Pd/ferrierite catalyst exhibited high alkene selectivity in the gas-phase hydrogenation of propyne. These results demonstrate that spray drying is not only a highly suited unit operation to prepare catalyst supports but also functional catalysts in one step. The method offers attractive opportunities for large-scale catalyst manufacture and as well as for preparation of well-defined systems for academic studies.

SWNT Sensors for Monitoring the Oxidation of Edible Oils

Abstract Several methods are available to measure the oxidation of edible oils, such as their acid, peroxide, and anisidine values. However, thesemethods require large quantities of reagents and are time-consuming tasks. Therefore, a more convenient and time-saving way to measurethe oxidation of edible oils is required. In this study, an edible oil-condition sensor was fabricated using single-walled nanotubes(SWNTs) made using the spray deposition method. SWNTs were dispersed in a dimethylformamide solution. The suspension was thensprayed using a spray gun onto a prefabricated Au/Ti electrode. To test the sensor, oxidized edible oils, each with a different acid value,were prepared. The SWNT sensors were immersed into these oxidized oils, and the resistance changes in the sensors were measured. Wefound that the conductivity of the sensors decreased as the oxidation level of the oil increased. In the case of the virgin oil, the resistancechange ratio in the SWNT sensor S(%) = {[(Rf _ Ri)]/Ri}(%) was more than 40% after immersion for 1 min. However, in the case of theoxidized oil, the resistance change ratio decreased to less than that of the response of the virgin oil. This result suggests that the change inthe oil components induced by the oxidation process in edible oils is related to the conductivity change in the SWNT sensor.

Deposition mechanism of dry sprayed ceramic particles at room temperature using a nano-particle deposition system

The nano-particle deposition system (NPDS) is a new dry spray process used to deposit metal and ceramic particles at room temperature. Low temperature deposition techniques for metals and ceramics that involve particle spraying include the NPDS, cold spray, and aerosol deposition methods. These are widely used to minimize thermal damage to the substrate when fabricating metal or ceramic layers. To optimize the process conditions for the intended applications and improve the deposition quality one must understand the mechanism of particle deposition at room temperature. The bonding mechanism in metal particle deposition by the cold spray method has already been researched. Adiabatic shear instability near the particle/substrate interface due to plastic deformation was reported to be the bonding mechanism for metal particles below the melting temperature. However, the bonding mechanism of ceramic particles has not been fully determined. This study assessed the bonding of ceramic particles by NPDS using numerical analysis and experimental results. A bonding mechanism is suggested after considering the experimental results for shock compaction, which is a process similar to that of the NPDS. The suggested deposition mechanism for ceramics involves the fragmentation of submicron ceramic particles into nanoparticles and the successive impact of submicron particles, which provides sufficient bonding energy, with heat and high pressure, to nanoparticles fragmented by the shock wave.

Effects of different needles and substrates on CuInS2 deposited by electrostatic spray deposition

Copper indium disulphide (CuInS2) thin films were deposited using the electrostatic spray deposition method. The effects of applied voltage and solution flow rate on the aerosol cone shape, film composition, surface morphology and current conversion were investigated. The effect of aluminium substrates and transparent fluorine doped tin oxide (SnO2:F) coated glass substrates on the properties of as-deposited CuInS2 films were analysed. An oxidation process occurs during the deposition onto the metallic substrates which forms an insulating layer between the photoactive film and substrate. The effects of two different spray needles on the properties of the as-deposited films were also studied. The results reveal that the use of a stainless steel needle results in contamination of the film due to the transfer of metal impurities through the spray whilst this is not seen for the glass needle. The films were characterised using a number of different analytical techniques such as X-ray diffraction, scanning electron microscopy, Rutherford back-scattering and secondary ion mass spectroscopy and opto-electronic measurements.

3371 Study on Formation of Films by a Spray Deposition Method for the Organic Thin Film Solar Cells

3371 Study on Formation of Films by a Spray Deposition Method for the Organic Thin Film Solar Cells

Investigation into microstructural properties of fluorapatite Nd-YAG laser clad coatings with PVA and WG binders

Biomedical implants are generally coated with a thin layer of hydroxyapatite (HA) using a plasma spraying or pulsed laser deposition method. However, the bonding strength between the coating layer and the substrate is relatively low. Moreover, the high temperature of the deposition process causes a structural instability of the HA, and therefore degrades its bioactivity and reduces the service life of the coating layer following implantation. Accordingly, the present study replaces HA with fluorapatite (FA) as the coating material, and examines the effects of two different binders, namely polyvinyl alcohol (PVA) and water glass (WG), on the properties of FA coatings deposited on Ti–6Al–4V substrates using an Nd-YAG laser cladding process. Scanning electron microscopy (SEM) observations reveal that the FA coating has a coral- and dendrite-like structure when mixed with the PVA binder, but a pure dendrite-like structure when mixed with the WG binder. In addition, the Ca/P value of the WG-based FA coating is significantly higher than that of the PVA-based coating. Fluorapatite, Al 2O 3, CaTiO 3 and Ca 3(PO 4) 2 phases are observed in both coating layers. However, the XRD analysis results indicate that the microstructure of the WG sample is dominated by Ca 3(PO 4) 2 phase while that of the PVA sample is dominated by FA. After soaking in SBF, it was observed that the specimen produced with PVA binder or less laser output power possessed a better apatite induction ability.