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In this work, the photocatalytic properties of thin films based on titanium oxides for application on flexible glass in photovoltaic panels were presented. Thin films were prepared by gas impulse magnetron sputtering (GIMS), where the gas injection on a target was synchronized in time with the electric pulse supplying the magnetron with the Ti target. The deposition process was carried out under various Ar/O2 atmospheres (with a content of 5–8% O2). The as-deposited TiOx films were non-stoichiometric. The influence of deposition parameters on optical properties, microstructure, hardness, and elastic modulus was examined. In addition, the dependence between the oxygen content in the sputtering atmosphere and the photocatalytic activity of the coatings was examined. The scratch resistance of the coatings and their adhesion to flexible glass were also investigated. It has been shown that the GIMS technique can be used for efficient deposition of non-stoichiometric TiOx coatings on substrates sensitive to the temperature as thin flexible glass and, at the same time, characterized by high adhesion. The TiOx-based semiconductor coatings prepared in this study can be used successfully in transparent electronics and in the construction of modern photovoltaic panels due to their photocatalytic activity, high hardness, and high level of transparency. [ABSTRACT FROM AUTHOR]

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In this paper, comparative studies on the structural, surface, optical, mechanical and corrosion properties of titanium dioxide (TiO2) thin films deposited by continuous and sequential magnetron sputtering processes were presented. In case of continuous process, magnetron was continuously supplied with voltage for 90 min. In turn, in sequential process, the voltage was supplied for 1 s alternately with 1 s break, therefore, the total time of the process was extended to 180 min. The TiO2 thin films were crack free, exhibited good adherence to the substrate and the surface morphology was homogeneous. Structural analysis showed that there were no major differences in the microstructure between coatings deposited in continuous and sequential processes. Both films exhibited nanocrystalline anatase structure with crystallite sizes of ca. 21 nm. Deposited coatings had high transparency in the visible wavelength range. Significant differences were observed in porosity (lower for sequential process), scratch resistance (better for sequential process), mechanical performance, i.e. hardness:elastic modulus ratio (higher for sequential process) and corrosion resistance (better for sequential process). [ABSTRACT FROM AUTHOR]

The biological and photocatalytic activity of TiO2 and TiO2:Cu in relation to their structure, surface topography, wettability and optical properties of the thin films was investigated. Thin-film coatings were prepared by magnetron sputtering method in oxygen plasma with use of metallic targets (Ti and Ti-Cu). The results of structural studies revealed that addition of Cu into titania matrix (during the deposition process) resulted in obtaining of an amorphous film, while in case of undoped TiO2, presence of nanocrystalline anatase (with crystallites size of 20 nm) was found. Moreover, an addition of cooper had also an effect on surface diversification and decrease of its hydrophilicity. The roughness of TiO2:Cu film was 25% lower (0.6 nm) as-compared to titania (0.8 nm). These modifications of TiO2:Cu had an impact on the decrease of its photocatalytic activity, probably as a result of the active surface area decrease. Antibacterial and antifungal properties of the thin films against bacteria (Enterococcus hirae, Staphylococcus aureus, Bacillus subtilis, Escherichia coli) and yeast (Candida albicans) were also examined. For the purpose of this work the method dedicated for the evaluation of antimicrobial properties of thin films was developed. It was revealed that Cu-additive has a positive impact on neutralization of microorganisms. [ABSTRACT FROM AUTHOR]

In this work the physicochemical and biological properties of nanocrystalline TiO2 thin films were investigated. Thin films were prepared by magnetron sputtering method. Their properties were examined by X-ray diffraction, photoelectron spectroscopy, atomic force microscopy, optical transmission method and optical profiler. Moreover, surface wettability and scratch resistance were determined. It was found that as-deposited coatings were nanocrystalline and had TiO2-anatase structure, built from crystallites in size of 24 nm. The surface of the films was homogenous, composed of closely packed grains and hydrophilic. Due to nanocrystalline structure thin films exhibited good scratch resistance. The results were correlated to the biological activity (in vitro) of thin films. Morphological changes of mouse fibroblasts (L929 cell line) after contact with the surface of TiO2 films were evaluated with the use of a contrast-phase microscope, while their viability was tested by MTT colorimetric assay. The viability of cell line upon contact with the surface of nanocrystalline TiO2 film was comparable to the control sample. L929 cells had homogenous cytoplasm and were forming a confluent monofilm, while lysis and inhibition of cell growth was not observed. Moreover, the viability in contact with surface of examined films was high. This confi rms non-cytotoxic effect of TiO2 film surface on mouse fibroblasts. [ABSTRACT FROM AUTHOR]

Titanium dioxide thin films doped with the same amount of neodymium were prepared using two different magnetron sputtering methods. Thin films of anatase structure were deposited with the aid of Low Pressure Hot Target Magnetron Sputtering, while rutile coatings were manufactured using High Energy Reactive Magnetron Sputtering process. The thin films composition was determined by energy dispersive spectroscopy and the amount of the dopant was equal to 1 at. %. Structural properties were evaluated using transmission electron microscopy and revealed that anatase films had fibrous structure, while rutile had densely packed columnar structure. Atomic force microscopy investigations showed that the surface of both films was homogenous and consisted of nanocrystalline grains. Photocatalytic activity was assessed based on the phenol decomposition. Results showed that both thin films were photocatalytically active, however coating with anatase phase decomposed higher amount of phenol. The transparency of both thin films was high and equal to ca. 80% in the visible wavelength range. The photoluminescence intensity was much higher in case of the coating with rutile structure. [ABSTRACT FROM AUTHOR]

Electrical and optical properties of TiO:Pd thin films deposited from Ti-Pd mosaic targets sputtered in reactive oxygen plasma have been studied. The properties were investigated for thin films with the Pd amount of 5.5 at. %, 8.4 at. % and 23 at. %. Based on resistivity measurements a drop from 10 down to almost 10Ωcm has been recorded when the Pd amount was varied from 5.5 at. % to 23 at. %, respectively. Moreover, it was shown that doping with different amounts of Pd results in the possibility of obtaining both types of electrical conduction: n-type for the TiO with 5.5 at. % and 8.4 at. % of Pd and p-type for the TiO with 23 at. % of Pd thin films. From optical measurements it has been found that as the Pd amount was increased the transmission through the thin films was reduced and position of the fundamental absorption edge was shifted toward a longer wavelength range of up to 600 nm. The optical band gap was calculated for direct and indirect transitions from optical absorption spectra. Structural properties were characterized by X-ray diffraction (XRD) and atomic force microscopy (AFM). The XRD patterns displayed occurrence of the crystalline, TiO-rutile for lower Pd amounts (5.5 at. %, 8.4 at. %), while the TiO:Pd (23 at. %) thin films displayed XRD-amorphous behaviour. Images obtained from AFM displayed dense, nanocrystalline structure with homogenous distribution of crystallites. Additionally performed secondary ion mass spectroscopy investigation confirmed homogenous distribution of Pd in the whole thickness of the prepared thin films. [ABSTRACT FROM AUTHOR]

[Display omitted] • XRD analysis results revealed that all deposited WO x thin films were amorphous. • Change of Ar:O 2 ratio in the sputtering atmosphere influenced WO x properties. • XPS results showed a decrease of O/W ratio from 3.01 to 2.55 for WO x thin films. • Increase of Ar:O 2 ratio caused the decrease of transmittance and band gap energy. • Electron and oxygen vacancy concentration increased with increase of Ar:O 2 ratio. • Ar:O 2 ratio of 7:1 was the best for use of WO x films in transparent electronics. In this paper, the structural, surface, optical, and electrical properties of tungsten oxide thin films were analyzed. Eight sets of WO x thin films were prepared using the magnetron sputtering method. In each case, the sputtering process parameters were the same, except the Ar:O 2 gas mixture ratios, which were intentionally changed from 1:1 to 10:1 to obtain various properties of the deposited thin film coatings. Structural properties analyzed with the aid of X-ray diffraction measurements results showed that all thin films were amorphous. X-ray photoelectron spectroscopy measurements revealed a shift of the binding energy for the W4f 7/2 peak towards lower energies for increasing Ar:O 2 ratio, indicating a possible change of stoichiometry and change of the oxygen vacancy concentration. It was also determined that the O/W atomic ratio at the surface of the thin films decreased from 3.01 to 2.55 with an increase of argon content in the magnetron sputtering atmosphere. Scanning electron microscope images revealed that all thin films had a smooth, homogenous, crack-free, and featureless, confirming the structural analysis. It was shown that the sputtering process atmosphere had a significant influence on the optical and electrical properties. Analysis of the transmittance spectra revealed that an increase of Ar:O 2 ratio caused a gradual decrease of the average transparency in the visible wavelength range, an increase of the fundamental absorption edge, and decrease of the optical band gap energy. Moreover, the refractive index and extinction coefficient were analyzed, showing that the change of the argon content in the sputtering atmosphere significantly influenced on those parameters. The sheet resistance and resistivity of the prepared WO x thin films decreased with the increase of Ar:O 2 ratio. The electrostatic charge dissipation times were measured for each coating to assess their antistatic properties. In turn, the hardness of tungsten oxide thin films increased with the increase of Ar:O 2 ratio. It was found that thin films deposited with Ar:O 2 ratio above 6:1 had good ability to dissipate static charge. Performed studies showed that a proper control of the gas atmosphere during magnetron sputtering of tungsten oxide thin films leads to tailoring their optoelectronic properties and creates an opportunity to design coatings destined for application in transparent electronics. [ABSTRACT FROM AUTHOR]