Properties Of Titanium Dioxide Films Research Articles

Effect of Ion-Beam Treatment on the Structure and Properties of Titanium-Oxide Films

Effect of Ion-Beam Treatment on the Structure and Properties of Titanium-Oxide Films

Semiconducting properties of surface-treated titanium and their effect on peel resistance: Experimental and modelling studies

Adhesively-bonded titanium components enable new design concepts in lightweight engineering but often lack long-term joint durability and endurance. Major challenges are related to the fact that the titanium/adhesive interface is susceptible to environmental ageing which leads to interfacial deadhesion. In the present work, the issue is addressed from the standpoint of semiconducting properties of surface TiO 2 films. Examination of surface treated, anodized cp-Ti has been conducted using electrochemical impedance spectroscopy (EIS). Semiconducting properties of titanium oxide films were derived from Mott-Schottky analysis whereas roller-peel tests were considered for joint strength assessment before and after accelerated ageing in climate chambers. The experimental study is complemented by a computational study on the adhesion force distribution during roller peel testing based on a cohesive zone FEM model. The studies show clear indication for a complex interaction between the adhesion contributing underlying physio-chemical mechanisms. Crucial insights into the electrochemistry at the respective interfaces and their relevance for joint design are provided.

Study of optical and photocatalytic properties of titanium oxide films with different oxidation degree

The results of studies of the optical and photocatalytic properties of titanium oxide films deposited by vacuum-arc evaporation in an oxygen-containing atmosphere are presented. It was experimentally shown that films of different degrees of oxidation are formed during deposition, depending on the amount of oxygen flow entering the working chamber. The results of studies of the obtained films showed that the films obtained in a transitional mode between the deposition of metallic Ti films and dielectric TiO2 films have the maximum photocatalytic activity. This deposition mode is observed at the oxygen flow into the working chamber from 9 to 12 cm3/min Keywords: titanium dioxide, anatase, photocatalytic activity.

Исследование оптических и фотокаталитических свойств пленок оксида титана разной степени окисления

The results of studies of the optical and photocatalytic properties of titanium oxide films deposited by vacuum-arc evaporation in an oxygen-containing atmosphere are presented. It was experimentally shown that films of different degrees of oxidation are formed during deposition, depending on the amount of oxygen flow entering the working chamber. The results of studies of the obtained films showed that the films obtained in a transitional mode between the deposition of metallic Ti films and dielectric TiO2 films have the maximum photocatalytic activity. This deposition mode is observed at the oxygen flow into the working chamber from 9 to 12 cm3/min.

Tailoring the physical properties of titania thin films with post deposition air and vacuum annealing

The present article carefully reports the influence of post deposition annealing on photophysical properties of titania (TiO 2 ) thin films, which are developed employing the electron-beam deposition technique. The pristine films are annealed at 100 °C, 200 °C, 300 °C in air and vacuum conditions followed by the investigation of photophysical properties employing several characterization tools viz. XRD, SEM, AFM, EDS, PL, UV Vis. spectrophotometer and source meter. The films showed amorphous nature, whereas Ti and O peaks in the EDS pattern are evident for TiO 2 films deposition. The increase in annealing temperature resulted into an increment in the transmittance (except for 100 °C) of air annealed films, whereas transmittance is decreased for vacuum annealed films. The obtained higher transmittance is suitable for TiO 2 thin films to implicate as buffer layer for solar cell devices where the band gap is observed in a range of 3.06–3.13 eV for air annealed and 2.57–3.05 eV for vacuum annealed films. The electrical conductance of films is enhanced up to 200 °C during annealing possibly due to the removal of traps present in titania thin films. AFM analysis of air annealed films demonstrates a decrement in surface roughness and grain size. Room temperature photoluminescence spectra exhibited strong peaks at 400 nm and 621 nm corresponding to the band edge and Ti 2+ , Ti 3+ , Ti 4+ surface state emissions, respectively. The higher transmittance, lower surface roughness, and ohmic nature of 300 °C air annealed films might attract kind attention for photoanode and optical window or buffer layer applications in dye-sensitized and Cd-based solar cells and charge transport layers in organic and perovskite solar cells. • An impact of air and vacuum annealing on properties of titania films is studied. • The structural analysis reveals the amorphous nature of pristine and annealed films. • Higher transmittance is observed for 300 °C air annealed titania films. • All the titania films showed conspicuous ohmic nature along with lower roughness. • The titania films air annealed at 300 °C may be applied as window or buffer layer.

Thermal Stability of the Structure and Optical Properties of Nanostructured TIO2 Films

The structure and optical properties of titanium dioxide films have been studied during annealing from 100 to 400°C. The films were obtained by ion-plasma high-frequency magnetron sputtering of polycrystalline rutile target in an argon atmosphere. It was shown that as-prepared TiO2 films are nanostructured with ~8 nm rutile crystallites and ~3.3 A interplanar distances and contain a small fraction of anatase. The optical band gap of the films is 3.01 eV, and the refractive index under normal conditions is 2.25. The film annealing at tamperatures from 100 to 400°C does not practically change their structure, optical band gap, and refractive index under normal conditions, i.e., the obtained nanostructured TiO2 films are thermally stable.

Study on the photoelectrical performance of anodized titanium sheets.

Anodization is a widely used method to obtain multicoloured oxidized titanium sheets. However, most researchers paid great attention to the colour-related properties instead of photoelectrical properties of titanium oxide film obtained by anodization. In this work, to study their photoelectrical properties, a series of multicoloured oxidized titanium sheets were prepared by anodization method, and UV–vis absorption and photocurrents were tested. The relationship between anodization voltages/anodization durations and photocurrents of titanium sheets was studied. Results show that titanium sheets have excellent photoelectrical performance. With the increase of anodization voltage, the number of UV–vis absorption peaks increased under visible light which means increasing absorption. When anodization duration increased, absorption band edge also increased in the visible light region, which means the band gap needed to produce charge transfer transition decreased. Under simulated sunlight and applied voltage of +0.4 V, photocurrent increased with the increase of either anodization voltage or anodization duration, and can be expressed by linear equations. In addition, anodization currents were recorded during anodization. Morphology, crystal structure and photoelectrical properties of anodized titanium sheets were characterized. The anodized titanium sheets can not only be used as decorative material in jewellery and architecture fields etc. but also are supposed to be used as photoelectrical catalyst in further work.

Исследование состава пленок оксидов титана, осажденных методом реактивного магнетронного распыления

The structure and properties of titanium oxide films deposited by reactive magnetron sputtering are studied. The results of the study of thin films using IR and Raman spectra show that the presence of a two-phase TiO2 structure and the formation of an N-O bond when nitrogen is introduced without the formation of titanium nitride (TiN), and may also indirectly indicate the presence of nitrogen oxide compounds in the film. It was found that the structure, element and phase composition of coatings depend on the value of the oxygen / nitrogen ratio in the composition of the reactive gas, as well as on the value of the negative displacement on the substrate. An increase in the proportion of nitrogen leads to a decrease in the spray rate. The obtained materials have the structure of anatase and rutile. The x-ray photoelectron spectroscopy method shows the presence of nitrogen (N) in The TiO2 lattice. In samples doped with nitrogen, a band appears in the Raman scattering spectra at 1048 cm-1 associated with the presence of nitrogen in TiO2. The elemental composition was also studied using an optical emission spectrometer of a glow discharge. Analysis of molecular bonding in the coatings was carried out using Fourier transform infrared spectroscopy. To measure Raman micro-spectra, a device developed at Fraunhofer IKTS-MD was used, consisting of a unit containing an inverted ZEISS optical microscope, Axiovert, and an iHR550 spectrometer with a cooled detector (Horiba, Jobin Yvon Inc.), A laser with a wavelength of 632.8 nm was used to excite the oscillations. Optical characteristics of coatings were studied on the spectral ellipsometric complex Эллипс-1891 САГ at a fixed angle of analysis of 70° in the range of wavelengths λ = 250-1000 nm.

Effect of composition nonstoichiometry on the optical properties of titanium dioxide films

It is established that the mechanisms of light absorption in titanium dioxide films differ in the visible and near-infrared spectral ranges. In the near-infrared range of the spectrum, the contribution to the absorption coefficient made by the intrinsic defects associated with the nonstoichiometry of the film composition is dominant. At the same time, in the visible spectral range, the main contribution to absorption is most likely made by external defects, namely, foreign inclusions and impurities contained in the starting material for film deposition. It is shown that the introduction of monitoring of the photothermal signal from the pellets of the raw material makes it possible to minimize and stabilize the absorption in the visible region of the spectrum.

聚乙二醇对二氧化钛薄膜结构及其自清洁性能的影响

聚乙二醇对二氧化钛薄膜结构及其自清洁性能的影响

Optical properties of titanium oxide films obtained by cathodic arc plasma deposition

Structural and optical properties of nanometric titanium oxide (TixOy) films obtained by cathodic arc plasma deposition were investigated. Phase analysis by x-ray diffraction and Fourier-transform infrared spectroscopy showed the presence of anatase, rutile, Ti2O3, Ti4O7 and amorphous phases. Scanning electron microscopy images showed well-developed surface morphology with nano-patterns. Spectroscopic ellipsometry revealed film thicknesses of 53 and 50 nm, variable refractive indices dependent on the light wavelength and close to zero extinction coefficients for wavelengths higher than 500 nm. On the basis of ultraviolet–visible spectroscopy data and using the Tauc equation, band gap values for direct and indirect electron transitions were determined.

Growth behaviors and biocidal properties of titanium dioxide films depending on nucleation duration in liquid phase deposition

Liquid phase deposition (LPD), which is a method to directly form a titanium dioxide (TiO2) film on a substrate, is the most practical method for applying TiO2 films to medical devices because it is performed at lower temperatures than other methods. The TiO2 films to be applied to medical devices should offer excellent antibacterial effect, but should be stable to normal cells and have appropriate strength. In this research, we observed that the size, shape, and density of TiO2 particles varied with the nucleation duration in LPD and confirmed that these results caused changes in several properties including the mechanical properties, cytotoxicity and antibacterial effect of TiO2 films. From the analysis of these results, we established the conditions for the preparation of TiO2 films that are suitable for medical devices and suggest a new approach to the study of TiO2 films prepared by LPD.

Stoichiometry and structure driven optical properties of carbon incorporated titanium oxide thin films

This study shows that the optical properties of titanium oxide films depend on their chemical composition as well as structure properties. The chemical composition as well as the structure of the sputter-deposited titanium oxide films on fused quartz glass substrates was modulated by annealing them in Ar/H2 atmosphere, experimentally investigated by various spectroscopic methods including XRD, Raman, SIMS, and UV-Vis spectroscopy and simulated by Bruggeman effective medium theory (BR-EMT) and full wave finite difference time domain (FDTD) approach. The as-deposited films are amorphous titanium oxide films with oxygen deficiency, become closer to titanium dioxide in stoichiometry, and are converted to crystalline anatase TiO2 nano-particles with particle size of ~21 nm by increasing the annealing temperature from 100 °C to 450 °C. The annealing process also allows the titanium oxide films to be spontaneously doped with environmental carbon species or coated with nano-crystalline graphitic carbon. Further the FDTD simulation results indicate that the annealed titanium oxide films become porous. The chemical composition modulation, anatase crystalline formation, carbon doping and graphitic carbon coating are simultaneously achieved by the simply annealing the sputter-deposited amorphous titanium oxide thin films on fused quartz substrates at relatively low temperatures.

Properties of TiO2 films with gold nanoparticles

The physicochemical and optical properties of titanium dioxide films, made by gel technology and doped with gold nanoparticles, were investigated. The structures of the titanium dioxide films synthesized by different techniques have been compared. Using methods of high-resolution microscopy and the results of X-ray diffraction analysis it was shown, that the developed gel technology allows getting almost 100% nanostructured anatase phase. Titanium dioxide was modified by nanoparticles of gold with different concentration and transmittance spectra of the samples were studied.

Crystalline phases and optical properties of titanium dioxide films deposited on glass substrates by microwave method

Abstract Anatase films were deposited on glass substrates by 180, 300, 450 and 500 W microwave for 1.5 min. Upon calcination the 450 and 500 W films at 450 °C for 1 h, additional rutile phase was detected by X-ray diffraction (XRD). Scanning electron microscopy (SEM) and atomic force microscopy (AFM) analyses revealed morphologies of the films which were composed of a number of nanoparticles orientated in different directions with the lowest roughness for the film synthesized by 450 W microwave combined with the high temperature calcination. Band gaps of the films without calcination determined by UV–visible spectroscopy were 3.30–3.35 eV and were considerably decreased to 2.92–3.20 eV by the high temperature calcination.

Effect of the duration of UV irradiation on the anticoagulant properties of titanium dioxide films.

Recently, UV irradiation has been reported as a new approach to significantly improve the anticoagulant properties of titanium dioxide (TiO2) films by suppressing fibrinogen adsorption and platelet adhesion. This study focuses on how fibrinogen adsorption of and platelet adhesion to TiO2 films is affected by the duration of UV irradiation. Furthermore, this study intends to describe the link between the suppression effect and the changes in the TiO2 films nature caused by photogenerated reactive oxygen species (ROS). First, we performed UV irradiation in different atmospheres as model 1 to determine the effect of oxygen gas on the anticoagulant properties of TiO2 films. The results showed that the suppression of platelet adhesion induced by UV irradiation depended on the presence of oxygen gas, indicating that ROS were photogenerated, and the ROS-induced surface change was related to the improvement in the anticoagulant ability. Then, we fabricated three other types of TiO2 samples in air by varying the UV irradiation time: (1) model 2, comprising fully UV-irradiated TiO2 films, (2) model 3, comprising partially UV-irradiated TiO2 films, and (3) model 4, comprising fully UV-irradiated TiO2-Si micropatterns. The results indicated that UV irradiation affected the anticoagulant properties of TiO2 films in a time-dependent manner. UV irradiation on TiO2 films for short duration (e.g., 1 min) evidenced a suppression effect on fibrinogen adsorption and platelet adhesion, an effect that could not be the result of photoinduced superhydrophilicity, increased hydroxyl groups (-OH) number, or decomposition of the adsorbed hydrocarbon. When the UV irradiation time was longer, this suppression effect extended from the surface of the UV-irradiated TiO2 films to the surface of the adjacent masked TiO2 films and the nearby Si surface. This result supported that the suppression effect could be related to the changes in the nature of the TiO2 films that were caused by the photogenerated and diffused ROS. Further, this extension of the suppression effect to the Si surface indicated that the photogenerated ROS could be used to improve the anticoagulant properties of other materials. A prolonged UV irradiation time (e.g., 240 min) may enhance the fibrinogen adsorption of and platelet adhesion to TiO2 films, which could be related to the decomposition of the adsorbed hydrocarbon and the increase in the positive charge. However, when comparing the enhancement effect and the suppression effect, the results showed that the latter was the main one to influence fibrinogen adsorption of and platelet adhesion to TiO2 films. This study provides an important basis for understanding the behavior of UV-irradiated TiO2 films as anticoagulant materials.

A Study on Structure and Optical Properties of Sputtered TiO<sub>2</sub> Films

Influence of argon flow on the optical properties of titanium oxide films, which were fabricated on well-polished K9 glass substrate through r.f. magnetron sputtering, has been investigated. X-ray diffraction (XRD) was employed to analyse the microstructure. Surface morphology was observed by atomic force microscopy (AFM). Transmittance of the films was measured within the visible range by UV-3600 spectrometer. The optical constants, such as thickness, refractive index and extinction coefficient, were measured using an ellipsometer. The experimental results and the effects of argon flow on optical constants of the TiO2 films have been discussed and analysed.

Electrophoretic Deposition of Titania Thin Films: Influence of Deposition Time on Microstructural and Optical Properties of the Coatings

Titania thin films were prepared by electrophoretic deposition at various deposition times (1, 5 and 10 min) in constant applied potential (5 V). For this purpose, modified titania sol was prepared as a colloidal suspension. The influence of deposition time on the thickness and optical properties of titania films was investigated. Scanning electron microscope images illustrate compact and homogeneous titania films deposited on FTO substrates. The results show that the film thickness increases with increasing the deposition time. It could be inferred from UV-Vis spectroscopy that increasing the thickness of deposited film causes higher absorbance at UV region. Also, increasing the deposition time from 1 to 5 min leads to increase in optical band gap of the deposited films.

Influence of Hydroxylamine Concentration on Structural and Electrical Properties of Titanium Oxide Films

Polycrystalline TiO2 films were electrodeposited on conductive substrates (NESA glass, Approximately 10Ω/□, Asahi glass Co. Ltd.) from the titanium potassium oxalate dehydrate aqueous solution containing hydroxylamine adjusted pH 9 with KOH aq. at 333K. For this electrochemical growth of TiO2 film, the reduction reaction of NH2OH plays an important role. In this paper, the influence of NH2OH concentration on the the structural property and photocatalysis of TiO2 film is discussed in detail.

Influence of Hydroxylamine Concentration on Structural and Electrical Properties of Titanium Oxide Films

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