Sputtering TiO2 Research Articles

Functional modification of TC4 by Cu-containing titanium dioxide films

To improve the biological fouling and corrosion resistance of Ti6Al4V (TC4) in marine environments, copper-containing titanium dioxide (TiO2(Cu)) films were prepared by magnetron sputtering TiO2(Cu) powder targets. The morphologies of the films showed that they became rough and coarse from 1.6 nm of the TiO2 film to approximately 9 nm of the TiO2(Cu) films, which might be owing to the increase in the deposition rates from 1.33 to 2.08 nm/min. No diffraction orientations of the TiO2 and Cu phases were found compared to those of the TiO2(Cu) powder. Ti, O, and Cu were detected using X-ray photoelectron spectroscopy to confirm the composition of the films. The ratio of Cu2+ increased as the Cu content of the films increased, whereas that of Cu/Cu + scarcely changed. The TiO2 and TiO2(Cu) films exhibited photocatalytic effects and their photocatalytic intensities decreased as the Cu content increased. Hydrophobicity was enhanced by the addition of Cu to the film. The antibiological fouling effect of the TiO2(Cu) films remained unchanged as the Cu/Ti ratio varied. Compared with those of TC4, the corrosion current densities of the TiO2(Cu) films decreased by one order of magnitude and the corrosion potentials increased by 350 mV in artificial seawater, indicating that the corrosion resistance of TiO2(Cu)/TC4 was improved. Importantly, Cu was in abundance in the films for both antibiological and corrosion resistance functions owing to the saturated ratio of Cu/Cu+ irrespective of the Cu/Ti ratio in the films.

Sliding and Corrosion Wear of Magnetron Sputtered TiO2 Films Deposited with Different Argon and Oxygen Mixtures

Sliding and Corrosion Wear of Magnetron Sputtered TiO2 Films Deposited with Different Argon and Oxygen Mixtures

Humidity sensor based on heterogeneous CoTiO3/TiO2 film with vertically aligned nanocrystalline structure

Vertically aligned nanocrystalline films with heterojunctions have attracted much attention as gas sensors because they provide high efficient transport pathways for carriers and large surface area with high activity for adsorption. In this work, a heterogeneous CoTiO3/TiO2 film is prepared by radio frequency sputtering TiO2 on prefabricated CoTiO3 film with a post annealing process. The vertically aligned nanocrystalline surface is achieved by atom inter diffusion and growth competition of the two phases. The obtained CoTiO3/TiO2 film shows nano-columnar arrays structure with dominant (104) orientation. As a humidity sensor, the film shows ultra-high response with fast response/recovery and good stability. The response value reaches 157.23 to 95% relative humidity, which is 38 times that of the pristine CoTiO3 film. Such excellent sensing performance is attributed to the corporation of vertically aligned nanocrystalline surface, advanced hydrophilicity and uniformly distributed heterojunctions.

Shell of black titania prepared by sputtering TiO2 target in H2 + Ar plasma

Black titania films that resemble the shell of recently reported black TiO2, were deposited by DC sputtering a conductive TiO2 target in a hydrogen-containing plasma. Synchrotron radiation was used for identifying the phases present in the samples. Anatase- defective rutile transformation, with further amorphization and transformation into intermediate Ti oxides were observed. Samples became black and conductive at the stage of transformation into defective rutile and the amorphous sample showed flat absorbance in the visible region. The amount of OH groups on the film surface reaches 80% with increasing hydrogen in the plasma. Nevertheless, the black samples are inferior photocatalytically to transparent titania. Based on the results, some new insights into the phenomenon of black TiO2 are provided.

TiO2/AZO bilayer thin films by magnetron sputtering as transparent electrodes for electrochromic devices

Transparent electrodes are dominated by a single material indium tin oxide (ITO). Indium has been classified as a critical raw material by the EU, thus some alternative transparent conductor materials are urgently required. Aluminum zinc oxide (AZO) has emerged as promising substitute due to its high transmittance and low resistivity as well as its low cost and resource availability. However, manufacturing processes for some optoelectronic devices such as electrochromic devices or organic light emitting diodes, chemically attack the AZO layers due to their instability against acidic and basic solutions. Chemical and environmental stability of AZO coatings must be improved to guarantee long-term stability of the devices. In this paper, electrochromic devices based on viologen modified nanostructured TiO2 layers have been manufactured on bilayer electrodes formed by sputtering TiO2 protective films on AZO layers. A thin sputtering TiO2 layer does not electrically insulate the AZO but improves its stability and protects it from being attacked during the deposition of the nanostructured sol-gel TiO2, enabling the fabrication of EC devices that switch properly between a transparent, colorless and a green coloured state. Optical contrast (ΔT %) values up to 40% have been reached with an operating voltage of −1.5 V.

Controllable deposition of TiO2 nanopillars at room temperature for high performance perovskite solar cells with suppressed hysteresis

A room temperature stratagy was proposed and realized for the fabrication of TiO2 scaffold for perovskite solar cells (PSCs). By sueccetively sputtering TiO2, thermal evaporating PTFE template and sputtering TiO2 again, bilayer TiO2 electron extraction layer was prepared with controllable porosity. Owning to the high sputtering power, the electron transport layer consisting of compact layer and TiO2 nanopillars was fully crystallized and no post thermal treatment was needed for the removal of PTFE template. The hysteresis of PSC was modulated and the porosity dependence of hysteresis was analyzed. PSC with a PCE of 15.08% and neglectable hysteresis was fabricated when the porosity of mesoporous scaffold was 45.77%. Our methodology offered a low cost room temperature scheme for the fabrication of mesostructured PSC. This approach makes large scale flexible PCS devices possible. What is more, this technique is versatile for the preparation of functional mesoporous materials with different pore structure and porosity requirements.

Sputtering TiO2 on LiCoO2 composite electrodes as a simple and effective coating to enhance high-voltage cathode performance

Abstract Surface coating is a key strategy in lithium-ion battery technologies to achieve a high and stable battery performance. Increasing the operation voltage is a direct way to increase the energy density of the battery. In this work, TiO 2 is directly sputtered on as-fabricated LiCoO 2 composite electrodes, enabling a controllable oxide coating on the topmost of the electrode. With an optimum coating, the discharge capacity is able to reach 160 mAh g −1 (86.5% retention) after 100 cycles within 3.0–4.5 V at 1 C, which is increased by 40% compared to that of the bare electrode. The high-voltage rate capability of LiCoO 2 is also remarkably enhanced after TiO 2 -coating as reflected by the much larger capacity at 10 C (109 vs. 74 mAh g −1 ). The artificially introduced oxide coating is believed to make the LiCoO 2 electrode more resistant to interfacial side reactions at high voltage and thus minimizes the irreversible loss of the active material upon long cycling. The TiO 2 coating layer is also possible to partially react with the decomposition product of electrolyte (e.g. HF) and form a more stable and conductive interphase containing TiF x , which is responsible for the improvement of the rate capability.

Supported TiO2 films deposited at different energies: Implications of the surface compactness on the catalytic kinetics.

Insight is provided in this study for the effect of the TiO2 film densification/compactness on polyethylene (PE-TiO2) by sputtering TiO2 at two very different energy levels. Uniform, adhesive low energy films were prepared by direct current magnetron sputtering (DCMS) and compared with films sputtered at high energy levels by high power impulse magnetron sputtering (HIPIMS). Nano-particulate TiO2 films sputtered by HPIMS presented sizes of ∼10.2nm compared to films sputtered by DCMS with TiO2 sizes of ∼16.5nm as determined by X-ray diffraction (XRD). The E. coli inactivation kinetics was three times faster for the samples sputtered by HIPIMS compared to their DCMS counterparts. This is an unexpected finding since the DCMS presenting larger TiO2 sized nanoparticles released a higher amount of Ti-ions compared to the HIPIMS samples as monitored by inductively coupled plasma mass-spectrometry (ICP-MS). The Ti-ions released do not seem to react through an oligodynamic effect but diffuse through the less compact TiO2 sputtered by DCMS. The faster bacterial inactivation kinetics observed by the HIPIMS sputtered samples can be understood in terms of the complete of Ti4+/Ti3+redox conversion during bacterial inactivation detected by X-ray photo-electron spectroscopy (XPS) compared to the smaller Ti4+/Ti3+ effect observed in the DCMS-samples. A higher optical density was detected for the HIPIMS sputtered samples by diffuse reflectance spectroscopy (DRS). Evidence is presented for the shift in surface potential and local pH during bacterial inactivation under aerobic and anaerobic conditions. A reaction mechanism is suggested based on the findings described in this study. The sputtered films present the potential to hinder biofilm formation on flexible thin polymers/textiles widely used in hospitals and health facilities.

TiO2薄膜的硼掺杂对TiO2/p+-Si异质结器件电致发光的增强

TiO2/p+-Si and TiO2∶B / p+-Si heterostructures were formed by sputtering TiO2 films and boron-doped TiO2( TiO2∶ B) films on heavily boron-doped silicon( p+-Si) substrates,respectively,followed by annealing at 600 ℃ in O2 ambient. In contrast with the TiO2/ p+-Si heterostructured devices,the TiO2∶ B / p+-Si counterpart exhibits markedly enhanced electroluminescence( EL). It is derived that the doped B atoms in TiO2∶ B films enter into the interstitial sites of TiO2 lattice after annealing at high temperature,which introduces excess oxygen vacancies. The increase of the concentration of oxygen vacancies due to B-doping leads to the enhancement of EL from the TiO2∶ B / p+-Si heterostructured devices because oxygen vacancies are the light-emitting centers of the TiO2/p+-Si heterostructured devices.

The Effects of Radio Frequency Sputtering of TiO<SUB>2</SUB> on Li[Li<SUB>0.07</SUB>Ni<SUB>0.38</SUB>Co<SUB>0.15</SUB>Mn<SUB>0.4</SUB>]O<SUB>2</SUB> Cathode for Lithium Ion Batteries

A radio frequency (RF) sputtering system is used to coat nano-thick TiO2 layer on the overlithiated layered metal oxide (OLO) electrode. The X-ray diffraction (XRD) and the field emission-scanning electron microscope (FE-SEM) images indicate amorphous TiO2 is coated on the top surface of the electrode with a thickness of approximately 20 nm for the 40 min sputtered sample. The sample sputtered for 40 minutes cycled at 90 mA g(-1) between 2 and 4.8 V versus Li+/Li has 15 mA h g(-1) more specific capacity at 100th cycle than that of the uncoated sample. In the voltage profiles, additional overpotential is unobservable upon sputtering TiO2 in comparison to that of the reference sample. Further analyses by the electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS) demonstrate the sputtered sample has less electrolyte decomposition products on the surface than that of the reference sample. Moreover, in the case of sputtering, reduced amount of transition metal and Li2O are deposited on the surface of the counter electrode, Li. In summary, the sputtered TiO2 acts as nano-sized artificial solid electrolyte interface (SEI) layer, which protects the surface of the electrode and improves kinetic properties, leading to improved performance.

Interference Phenomena Observed on an Atomic Force Microscope Cantilever by Laser Confocal Microscopy

We investigated interference phenomena that were observed on a cantilever bar of an atomic force microscope by using a laser confocal microscope (LCM). First, we established a simple model and calculated the fringe interval. Interference fringe patterns were observed under the following conditions: (1) changing the focus and confocal aperture of the LCM, (2) increasing the reflectance by sputtering TiO2 on the cantilever bar and glass plate, and (3) changing the medium from air to water in the space between the glass plate and the cantilever. The purpose of a previous experiment was to measure the refractive index of water. It was theoretically determined that the fringe interval depended not on the height of the cantilever from the surface but on the wavelength, refractive index, and tilt angle of the cantilever. We obtained the following experimental results: (1) the fringe interval was independent of the confocal plane when using a monochromatic laser, (2) a sharpened interference fringe was observed when we used a TiO2-coated cantilever and glass plate, and (3) the refractive index of a small quantity of water could be measured.

Interference Phenomena Observed on an Atomic Force Microscope Cantilever by Laser Confocal Microscopy

We investigated interference phenomena that were observed on a cantilever bar of an atomic force microscope by using a laser confocal microscope (LCM). First, we established a simple model and calculated the fringe interval. Interference fringe patterns were observed under the following conditions: (1) changing the focus and confocal aperture of the LCM, (2) increasing the reflectance by sputtering TiO2 on the cantilever bar and glass plate, and (3) changing the medium from air to water in the space between the glass plate and the cantilever. The purpose of a previous experiment was to measure the refractive index of water. It was theoretically determined that the fringe interval depended not on the height of the cantilever from the surface but on the wavelength, refractive index, and tilt angle of the cantilever. We obtained the following experimental results: (1) the fringe interval was independent of the confocal plane when using a monochromatic laser, (2) a sharpened interference fringe was observed when we used a TiO2-coated cantilever and glass plate, and (3) the refractive index of a small quantity of water could be measured.

High Temperature Sputtered TiO2 Film as an Efficient Blocking Layer for the Dye-sensitized Solar Cells

We investigated the carrier leakage blocking effect of the magnetron sputtered TiO2 film insertion between transparent anodic electrode and porous TiO2 film in the dye-sensitized solar cell (DSC), as a consequence of preventing the ionic short-circuiting of the electrolyte to the anodic electrode through porous TiO2 film. The optimization of the deposition condition of the high temperature TiO2 sputtering for the carrier leakage blocking is reported.