Fabrication of solid thin film electrolyte and LiCoO2 by aerosol flame pyrolysis deposition

Aerosol flame pyrolysis deposition method was applied to deposit the oxide glass electrolyte film and LiCoO₂ cathode for thin film type Li-ion secondary battery. The thicknesses of as-deposited porous LiCoO₂ and Li₂O–B₂O₃–P₂O₅ electrolyte film were about 6 μm and 15 μm, respectively. The deposited LiCoO₂ was sintered for 2 min at 700 °C to make partially densified cathode layer, and the deposited Li₂O–P₂O₅–B₂O₃ glass film completely densified by the sintering at 700 °C for 1 h. After solid state sintering process the thicknesses were reduced to approximately 4 μm and 6 μm, respectively. The cathode and electrolyte layers were deposited by continuous deposition process and integrated into a layer by co-sintering. It was demonstrated that Aerosol flame deposition is one of the good candidates for the fabrication of thin film battery.     

One-pot electrosynthesis of polyglycine-like thin film on platinum electrodes as transducer for solid state pH measurements

The anodic oxidation of concentrated glycine based aqueous electrolyte on smooth platinum electrode leads to a strongly grafted polyglycine-like coating on the surface in an irreversible way. Due to the proton affinity towards amino groups of polyglycine (PG), the electrodeposited thin film was used as receptor for solid potentiometric pH sensor. In order to reach local pH measurement, we developed miniaturized microelectrodes on glass substrate thanks to photolithography process. We used silver chloride on silver as the reference electrode. The couple (silver chloride, PG based platinum electrode) of microelectrodes gives linear potentiometric response vs. pH in the range [2-12], reversibly and with a sensitivity of 52.4 mV/pH (for 1 mm electrode size). PG based pH electrode is compared to other organic polymer based pH receptor such as linear polyethylenimine (L-PEI), polyaniline (PANI) and glass membrane.     

Fabrication of solid thin film electrolyte and LiCoO2 by aerosol flame pyrolysis deposition

Aerosol flame pyrolysis deposition method was applied to deposit the oxide glass electrolyte film and LiCoO₂ cathode for thin film type Li-ion secondary battery. The thicknesses of as-deposited porous LiCoO₂ and Li₂O–B₂O₃–P₂O₅ electrolyte film were about 6 μm and 15 μm, respectively. The deposited LiCoO₂ was sintered for 2 min at 700 °C to make partially densified cathode layer, and the deposited Li₂O–P₂O₅–B₂O₃ glass film completely densified by the sintering at 700 °C for 1 h. After solid state sintering process the thicknesses were reduced to approximately 4 μm and 6 μm, respectively. The cathode and electrolyte layers were deposited by continuous deposition process and integrated into a layer by co-sintering. It was demonstrated that Aerosol flame deposition is one of the good candidates for the fabrication of thin film battery.     

Fabrication and optical properties of gallium phosphide nanoparticulate thin film

The gallium phosphide (GaP) nanoparticulate thin films were fabricated by colloidal suspensions deposition with GaP nanoparticles dispersed in N,N-dimethylformamide (DMF). The microstructure and optical properties of the film have been studied by scanning electron microscopy, high resolution transmission electron microscope, and optical absorption and fluorescence spectra. The morphology of the film was found to be composed of nanoparticle aggregates, and with an irregularly rough surface. From the result of fluorescence, it can be established that the film not only retains the violet and blue light emissions which ascribed to transition from conduction band to valence band of gallium phosphide particles, but has an excellent luminescence property. The correlation between the optical properties and the microstructure of the thin film is discussed.     

Comparison of DSC and optical transmission measurements of polymorphic transitions

Using optical measurements on single crystals, the speed of first order transitions (K₂Cr207, KNO₃, AgNO₃) was determined and compared with the strongly smeared DSC signals. Such optical measurements are proposed to select materials which are suitable for the determination of the DSC apparatus function.

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Zusammenfassung Mit Hilfe von optischen Messungen wird die Geschwindigkeit von polymorphen Phasenumwandlungen 1. Ordnung (K₂Cr₂O₇, KNO₃, AgNO₃) bestimmt und mit entsprechenden stark verschmierten DSC-Signalen verglichen. Derartige optische Messungen erscheinen geeignet, um Substanzen zu suchen, welche für die Bestimmung der DSC-Apparatefunktion geeignet sind.

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K₂Cr₂O₇, KNO₃ AgNO₃ $ , $ . , $ .

     

Polyaniline thin film optical waveguides for integrated optics and VLSI prepared by vacuum evaporation technique

Polyaniline is emerging as an important polymer material which offers challenging opportunities for both fundamental research and new technological applications in waveguides. Metal doped polyaniline has been prepared initially in the form of powder by a solution growth technique. The emeraldine salt with doped metal was also prepared by solution growth technique. This powder was used for vacuum evaporation on optically flat glass substrate. The dark green doped (Fe, Al) polyaniline thin films were prepared by vacuum evaporation technique (10^?4 torr). Deposited waveguide thin films have been characterized structurally, using X‐ray diffraction (XRD), optically etc. Effective refractive index of the thin film waveguide was also calculated theoretically and experimentally. Waveguide parameters, namely refractive index, propagation loss and depth of vacuum deposited polyaniline thin films optical waveguide have been determined. The optical spectra and structure and waveguide parameters of vacuum deposited polyaniline thin films are strongly affected by the type of doping. It is possible to reduce the losses by addition of Fe to the vacuum deposited polyanine thin film and modify the effective refractive index (O_eff) according to particular requirements. Results are compared with the results in the literature. Copyright © 2002 John Wiley & Sons, Ltd.     

Recalibration of U-doped standard glasses through uranium thin film for neutron-fluence measurements

This work presents a recalibration of U-doped standard glasses using natural uranium thin films to be used as most dedicated neutron monitor for fission-track dating. The recalibrated U-doped glasses were used to determine fission-track ages in apatite samples from Brazilian alkaline formations (Alto Paranaíba) and standard Durango apatite. Samples were irradiated in two nuclear reactors with different characteristics and the results were compared. For well-thermalized neutron facility, metal activation monitor was also used. The ages of Alto Paranaíba arch and Durango apatite agree with those determined by other radiometric dating methods and metal activation monitors. These results suggest that the presented recalibration is suitable to be used routinely for fission-track dating studies even in a non-well thermalized neutron facility.     

The morphological,optical and electrical properties of SnO2:F thin films prepared by spray pyrolysis

Combining the spray pyrolysis and the sol–gel techniques gives the possibility to produce Fluorine doped Tin oxide (SnO₂:F) thin films. Transparent conducting SnO₂:F thin films have been deposited on glass substrates by the spray pyrolysis technique. This technique for the fabrication of SnO₂:F filmsby combining sol–gel process and the spray pyrolysis technique ispresented in this paper. The Sol–gel precursors have been successfully prepared using SnCl₂·5H₂O and (Ac)F₃. The structural, electrical, and optical properties of these films were investigated. The high resolution transmission electron microscopy (HRTEM) and selected area diffraction (SAD) patterns of SnO₂:F films show that the gel films lead to a tetragonal structure. The X‐ray diffraction pattern of the films deposited at substrate temperature 530° , the orientation of the films was predominantly [110]. In addition, the surface chemical components were also examined by X‐ray photoelectron spectroscopy (XPS) showing the SnO₂:F deposited with the atomic concentration ratios Sn/F 1.82:1. The minimum sheet resistance was 50 Ω and average transmission in the visible wavelength range of 300 to 800 nm was 87.25%. Copyright © 2008 John Wiley & Sons, Ltd.     

Vapor-assisted epitaxial growth of porphyrin-based MOF thin film for nonlinear optical limiting

Fabrication of metal-organic frameworks(MOFs) thin films has been an efficient way to expand their functionalities and applications. Here, we use the vapor-assisted deposition(VAD) method to epitaxially grow a porphyrin-based MOF PCN-222 film. That is, vapor source assists to deposit pre-treated precursor solution on quartz substrate to form a continuous PCN-222 film. Furthermore, utilizing the post-treated encapsulation of functional carbon-based nanoparticles, the carbon nanodots(CND)and Pt doped CND(Pt/CND) are well loaded into the pores of PCN-222 film, the size(～3.1 nm) of which is highly close to the pore size of the corresponding MOF(～3.7 nm). The Z-scan results reveal that PCN-222 film exhibits high reverse saturable absorption. In addition, encapsulation of carbon based nanodots into PCN-222 film could enhance the nonlinear optical limiting effect benefiting from the host-guest combination. This study serves to present both the available toolbox of thin film preparation and high potential for precise synthetic nanocomposite films in optical limiting devices.     

Molecular weight effect on latex film formation induced by solvent vapor: an optical transmission study

Vesicular electrokinetic chromatography was used to investigate solute partitioning from the aqueous phase into dihexadecyl hydrogen phosphate (DHP) vesicles. Retention factors of neutral solutes are related to their partition coefficients between the aqueous phase and vesicles (K(vw)). The K(vw) of the aromatic test solutes were readily obtained from the slopes of the linear relationships between retention factors versus DHP concentrations. The technique offers the advantages of speed, automation, and small sample size for determination of partition coefficients. The K(vw) values of 43 uncharged solutes were measured at below as well as above the phase transition temperatures. The logarithms of partition coefficients (log K(vw)) of solutes at 71 degrees C (above T(c)) were slightly higher than those at 36 degrees C (below T(c)). The solvation characteristics of DHP were also studied using linear solvation energy relationships at the two temperatures.     

Structural, optical, and magnetic properties of Mn-doped ZnO thin film

The Zn(1-x)Mn(x)O (x = 0, 0.16, and 0.25) thin films were grown on fused quartz substrates by reactive magnetron cosputtering. X-ray-diffraction measurement revealed that all the films were single phase and had wurtzite structure with c-axis orientation. As Mn concentration increased in the Zn(1-x)Mn(x)O films, the c-axis lattice constant and band-gap energy increased gradually. In Raman-scattering studies, an additional Mn-related vibration mode appeared at 520 cm(-1). E(2H) phonon line of Zn(1-x)Mn(x)O alloy was broadened asymmetrically and redshifted as a result of microscopic structural disorder induced by Mn(2+) random substitution. The Zn(0.84)Mn(0.16)O film exhibited a ferromagnetic characteristic with a Curie temperature of approximately 62 K. However, with increasing Mn concentration to 25 at. %, ferromagnetism disappeared due to the enhanced antiferromagnetic superexchange interactions between neighboring Mn(2+) ions.     

Crystalline ZnO thin film by hydrothermal growth

In this work, we have successfully synthesised ZnO crystal thin film with a high quality from hydrothermal reaction on sapphire substrate. The growth mechanism is clarified based on an extensive XTEM study. In addition, electrical and optical properties of the crystal thin film, which can be controlled by impurities, are characterized. The synthesis technique provides fairly high quality and cost-effective substrates for optoelectronic and renewable energy applications.     

Simultaneous calorimetric and optical reflectivity measurements of extremely thin liquid crystal films

Abstract

An extremely sensitive measuring system has been developed to obtain simultaneously heat capacity and optical reflectivity data from thin free-standing liquid crystal films. Results from 3(10)OBC near the smectic A to hexatic B transition will be reported and discussed in the context of recent theory regarding phase transitions in two dimensions.     

Comparison of optical and structural properties of nanostructure TiO2 thin film doped by Sn and Nb

The thin films of TiO₂ doped by Sn or Nb were prepared by sol–gel method under process control. The effects of Sn and Nb doping on the structural, optical and photo-catalytic properties of applied thin films have been studied by X-ray diffraction (XRD) high resolution transmission electron microscopy and UV–Vis absorption spectroscopy. Surface chemical state of thin films was examined by atomic X-ray photoelectron spectroscopy. XRD results suggest that adding impurities has a great effect on the crystallinity and particle size of TiO₂. Titania rutile phase formation in thin film was promoted by Sn⁴⁺ addition but was inhibited by Nb⁵⁺ doping. The activity of the photocatalyst was evaluated by photocatalytic degradation kinetics of aqueous methylene blue under UV and Visible radiation. The results show that the photocatalytic activity of the Sn-doped TiO₂ thin film have a larger degradation efficiency than Nb-doped TiO₂ under visible light, but under UV light photocatalytic activity of the Nb-doped TiO₂ thin film is better.     

Preparation and optical properties of Bi2S3 microcrystallite doped glass and thin film by the sol-gel process

The Bi₂S₃ microcrystallite doped thin films and glass lumps have been successfully prepared by the sol-gel process from the hydrolysis of a complex solution of Si(OC₂H₅)₄ Bi(NO₃)₃ · 5H₂O and SC(NH₂)₂, and the size of the microcrystallites in glass heated for different times at 400°C was decided by the method of HRTEM. The optical transmission valley shifted towards longer wavelengths with longer heat-treatment time at 500°C in the Bi₂S₃ doped thin films, showing the experimental evidence of quantum size effects. The red-shift of emission peaks in luminenscence spectrum excited with longer wavelength is attributed to the broad distribution of particle size in Bi₂S₃ doped glass.     

Glucose oxidase-incorporated hydrogel thin film for fast optical glucose detecting under physiological conditions

Hydrogel biosensors usually suffer from a slow response, which severely hinders their practical applications. Here a new optical glucose biosensor was designed, using glucose-sensitive hydrogel films as both glucose-sensing material and Fabry-Perot cavity. The film was fabricated by layer-by-layer assembly from partially oxidized dextran (PO-Dex), chitosan, and glucose oxidase (GOD). The film responds to glucose because the incorporated GOD converts glucose to gluconic acid, and thus lowers the local pH in the film, and, in turn, triggers the pH-sensitive film to swell. The glucose-induced swelling causes a shift of Fabry?Perot fringes on the reflection spectra of the film, from which the glucose concentration can be reported. The new sensor works well under physiological conditions. Potential interferents, such as diols for phenylboronic acid-based sensors and electroactive compounds for electrochemical sensors, do not influence the new sensor. The sensor can respond reversibly over a wide range of glucose concentration. Particularly, it responds linearly within the clinically relevant glucose range (0–20 mM). More importantly, because the film is very thin, the new sensor can respond quickly, making it potential for real-time, continuous glucose monitoring.     

Synthesis of cobalt doped silica thin film for low temperature optical gas sensor

A modified sol–gel method was used to prepare cobalt doped silica thin film with a cobalt content of 10, 20 and 30 mol% (10Co, 20Co and 30Co). The prepared films were annealed at different temperatures in the range 400–1,000 °C, and their structural evolution examined. The mixed valence cobalt oxide, Co₃O₄, crystallizes only in the sample with the higher cobalt content, while cobalt silicate is the only crystalline phase detected in the sample 10Co and 20Co. Both the cobalt content and the temperature of heat treatment resulted to affect the nature of cobalt species dispersed in the silica matrix. The 30Co was selected for further investigations by FTIR spectroscopy to follow the structural evolution of 30Co film as function of the temperature and UV–Vis to get information on the cobalt valence state. The optical gas-sensing properties of 30Co films, containing Co₃O₄ as the major cobalt phase, were studied through the measuring of the film transmittance in dry air and in presence of dry air containing variable concentrations of polluting gases, CO and NO₂. The 30Co samples resulted to be highly sensitive to CO at room temperature. An explanation for the CO sensing characteristics, at low temperature, was proposed by referring to the physisorption-related mechanics of CO.     

Error minimization in the envelope method for the determination of optical constants of a thin film

The algorithm for the determination of optical constants of a weakly absorbing thin film from the envelope method has been modified to minimize the error in the estimated values of extinction coefficient (k) as a function of wavelength. The refinement procedure is based on an extension of interference order adjustment method used for improving the estimated values of film thickness d and wavelength‐dependent refractive index n from the envelope method. The proposed modification when applied to a hypothetical as well as an experimental film is found to work well over a wide spectral region. Copyright © 2010 John Wiley & Sons, Ltd.     

A composite thin film optical sensor for dissolved oxygen in contaminated aqueous environments

A robust optical composite thin film dissolved oxygen sensor was fabricated by ionically trapping the dye ruthenium(II) tris(4,7-diphenyl-1,10-phenanthroline) dichloride in a blended fluoropolymer matrix consisting of Nafion^® and Aflas^®. Strong phosphorescence, which was strongly quenched by dissolved oxygen (DO), was observed when the sensor was immersed in water. The sensor was robust, optically transparent, with good mechanical properties. Fast response, of a few seconds, coupled with sensitivity of about 0.1 mg L⁻¹ (DO) over the range 0-30 mg L⁻¹ and resistance to leaching, were also exhibited by this system. The Stern-Volmer (SV) plot exhibited slight downward turning at all oxygen concentrations. A linear plot was obtained when the SV equation was modified to account for the varying sensitivity of dye molecules in the matrix to the quencher. Good long term stability was observed.     

In situ conductance measurements of copper phthalocyanine thin film growth on sapphire [0001

The current flowing through a thin film of copper phthalocyanine vacuum deposited on a single crystal sapphire [0001] surface was measured during film growth from 0 to 93 nm. The results, expressed as conductance vs. nominal film thickness, indicate three distinct film growth regions. Conductive material forms below about 5 nm and again above 35 nm, but in the intermediate thicknesses the film conductance was observed to decrease with increasing film thickness. With the aid of ac-AFM topology images taken ex situ, the conductance results are explained based on the Stranski-Krastanov (2D + 3D) film growth mechanism, in which the formation of a thin wetting layer is followed by the growth of discrete islands that eventually coalesce into an interpenetrating, conductive network.