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Sample records for tio2 thin films

  1. Multivalent Mn-doped TiO2 thin films

    Science.gov (United States)

    Lin, C. Y. W.; Channei, D.; Koshy, P.; Nakaruk, A.; Sorrell, C. C.

    2012-07-01

    Thin films of TiO2 doped with Mn were deposited on F-doped SnO2-coated glass using spin coating. The concentration of the dopant was in the range 0-7 wt% Mn (metal basis). The films were examined in terms of the structural, chemical, and optical properties. Glancing angle X-ray diffraction data show that the films consisted of the anatase polymorph of TiO2, without any contaminant phases. The X-ray photoelectron spectroscopy data indicate the presence of Mn3+ and Mn4+ in the doped films as well as atomic disorder and associated structural distortion. Ultraviolet-visible spectrophotometry data show that the optical indirect band gap of the films decreased significantly with increasing manganese doping, from 3.32 eV for the undoped composition to 2.90 eV for that doped with 7 wt% Mn.

  2. Superhydrophilicity of TiO2 nano thin films

    International Nuclear Information System (INIS)

    Full text: Among the several oxide semiconductors, titanium dioxide has a more helpful role in our environmental purification due to its photocatalytic activity, photo-induced superhydrophilicity, and as a result of them non-toxicity, self cleaning, and antifogging effects. After the discovery of superhydrophilicity of titanium dioxide in 1997, several researches have been performed due to its nature and useful applications. The superhydrophilicity property of the surface allows water to spread completely across the surface rather than remains as droplets, thus making the surface antifog and easy-to-clean. The distinction of photo-induced catalytic and hydrophilicity properties of TiO2 thin films has been accepted although, the origin of hydrophilicity property has not been recognized completely yet. TiO2 thin films on soda lime glass were prepared by the sol-gel method and spin coating process. The calcination temperature was changed from 100 to 550 C. XRD patterns show increasing the content of polycrystalline anatase phase with increasing the calcination temperature. The AFM results indicate granular morphology of the films, which particle size changes from 22 to 166 nm by increasing the calcination temperature. The RBS, EDX and Raman spectroscopy of the films show the ratio of Ti:O?0.5, and diffusion of sodium ions from substrate into the layer, by increasing the calcination temperature. The UV/Vis. spectroscopy of the films indicates a red shift by increasing the calcination temperature. The contact angle meter experiment shows that superhydrophilicity of the films depends on the formation of anatase crystal structure and diffused sodium content from substrate to the layer. The best hydrophilicity property was observed at 450 C calcination temperature, where the film is converted to a superhydrophilic surface after 10 minutes under 2mW/cm2 UV irradiation. TiO2 thin film on Si(111), Si(100), and quartz substrates needs less time to be converted to superhydrophilic surface rather than glass and polycrystalline Si substrates. Our results are consistent with the idea that UV-induced wetting of TiO2 surface is caused by the removal of hydrophobic layers of hydrocarbons by TiO2-mediated photo-oxidation, which leads to the attractive interaction of water with clean TiO2 surface. (authors)

  3. Fe-doped TiO 2 thin films

    Science.gov (United States)

    Mardare, Diana; Nica, Valentin; Teodorescu, Cristian-Mihail; Macovei, Dan

    2007-09-01

    The reactive sputtering technique was used to obtain undoped and Fe-doped TiO 2 thin films deposited on glass substrates. At 250 °C substrate temperature, undoped TiO 2 films crystallize in a mixed rutile/anatase phase, while Fe-doped films exhibit the rutile phase only. Presence of Fe 3+ ions into the TiO 2 lattice is suggested by the intensity variation of forbidden 1s ? 3d transitions between the Ti and Fe K-edges. Ti K-edge EXAFS data are assessed to a mixture of the two kinds of surroundings, a rutile-like crystalline phase, identified also by X-ray diffraction, and a nanosized or amorphous anatase-like surrounding. The local atomic order about Fe atoms is quite different and could be related also to an amorphous phase. The Swanepoel method is used to obtain the dispersion of the refractive index below the interband absorption edge. The dispersion energy, the single-oscillator energy and the coordination number of the Ti atoms are evaluated using the single-oscillator model (Wemple-DiDomenico).

  4. Picosecond nonlinear optical transmission measurement on anatase TiO2 thin films

    International Nuclear Information System (INIS)

    A TiO2 optical thin film is fabricated by use of a sol-gel method. The structure of the TiO2 thin film is examined by using an X-ray diffraction measurement, which shows that the gelation process at 500 .deg. C results in an anatase phase. A nonlinear optical transmission measurement is performed by pumping near the energy gap edge of the TiO2 thin film. The nonlinear optical responses of the d- and the sp-orbitals are found to be responsible for the large optical Kerr nonlinearity in the anatase TiO2 thin film.

  5. Quantification of phase content in TiO2 thin films by Raman spectroscopy

    Scientific Electronic Library Online (English)

    V.H., Castrejón-Sánchez; Enrique, Camps; M., Camacho-López.

    Full Text Available Recently, it has been reported that TiO2 with mixture of phases (anatase/rutile) exhibit higher photocatalytic activity than TiO2 with pure anatase phase. Therefore, the production and correct quantification of the ratio of phases becomes an important task. In this work, anatase TiO2 thin films were [...] obtained by the DC reactive magnetron sputtering technique. TiO2 with mixture of phases (anatase/rutile) were prepared by thermal annealing of the as-deposited thin films. The value of the anatase/rutile ratio in the titanium dioxide thin films was estimated using Raman spectroscopy. Additionally, it is reported the dependence of the bandgap of the TiO2 thin films as a function of the anatase/rutile ratio. The band gap of the TiO2 thin films was determined from diffuse reflectance measurements.

  6. Optical Properties and Surface Morphology of Nano-composite PMMA: TiO2 Thin Films

    International Nuclear Information System (INIS)

    There are two nano-composite PMMA: TiO2 solutions were prepared in this research. First solution is nano-composite PMMA commercially available TiO2nanopowder and the second solution is nano-composite PMMA with self-prepared TiO2 powder. The self-prepared TiO2 powder is obtained by preparing the TiO2 sol-gel. Solvo thermal method were used to dry the TiO2 sol-gel and obtained TiO2 crystal. Ball millers were used to grind the TiO2 crystal in order to obtained nano sized powder. Triton-X was used as surfactant to stabilizer the composite between PMMA: TiO2. Besides comparing the nano-composite solution, we also studied the effect of the thin films thickness on the optical properties and surface morphology of the thin films. The thin films were deposited by sol-gel spin coating method on glass substrates. The optical properties and surface characterization were measured with UV-VIS spectrometer equipment and atomic force microscopy (AFM). The result showed that nano-composite PMMA with self prepared TiO2 give high optical transparency than nano-composite PMMA with commercially available TiO2 nano powder. The results also indicate as the thickness is increased the optical transparency are decreased. Both AFM images showed that the agglomerations of TiO2 particles are occurred on the thin films and the surface roughness is increased when the thsurface roughness is increased when the thickness is increased. High agglomeration particles exist in the AFM images for nano-composite PMMA: TiO2 with TiO2 nano powder compare to the other nano-composite solution. (author)

  7. Photocatalytic properties of porous TiO2/Ag thin films

    International Nuclear Information System (INIS)

    In this study, nanocrystalline TiO2/Ag composite thin films were prepared by a sol-gel spin-coating technique. By introducing polystyrene (PS) spheres into the precursor solution, porous TiO2/Ag thin films were prepared after calcination at a temperature of 500 deg. C for 4 h. Three different sizes (50, 200, and 400 nm) of PS spheres were used to prepare porous TiO2 films. The as-prepared TiO2 and TiO2/Ag thin films were characterized by X-ray diffractometry (XRD) and by scanning electron microscopy to reveal structural and morphological differences. In addition, the photocatalytic properties of these films were investigated by degrading methylene blue under UV irradiation. When PS spheres of different sizes were introduced after calcination, the as-prepared TiO2 films exhibited different porous structures. XRD results showed that all TiO2/Ag films exhibited a major anatase phase. The photodegradation of porous TiO2 thin films prepared with 200 nm PS spheres and doped with 1 mol% Ag exhibited the best photocatalytic efficiency where ? 100% methylene blue was decomposed within 8 h under UV exposure

  8. PHOTOCATALYTIC PROPERTIES OF Cr DOPED TiO2–SiO2 NANOSTRUCTURE THIN FILM

    Directory of Open Access Journals (Sweden)

    Akbar Eshaghi

    2012-07-01

    Full Text Available Cr doped TiO2–SiO2 nanostructure thin film on glass substrates was prepared by a sol-gel dip coating method. X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS and UV-vis spectrophotometer were used to characterize the structural, chemical and optical properties of the thin film. The XRD showed that thin films contain only anatase phase. FE-SEM images illustrated that anatase average crystallite size in the pure TiO2 and Cr doped TiO2–SiO2 thin films are 15 nm and 10 nm, respectively. XPS spectra confirmed the presence of Cr3+ in the thin film. UV-vis absorption spectra indicated that absorption edge in Cr doped TiO2–SiO2 thin film shifted to the visible light region. The photocatalytic results pointed that Cr doping in TiO2–SiO2 improved decoloring rate of methyl orange in comparison to pure TiO2 thin film.

  9. Biocompatibility and Surface Properties of TiO2 Thin Films Deposited by DC Magnetron Sputtering

    Directory of Open Access Journals (Sweden)

    Francisco López-Huerta

    2014-05-01

    Full Text Available We present the study of the biocompatibility and surface properties of titanium dioxide (TiO2 thin films deposited by direct current magnetron sputtering. These films are deposited on a quartz substrate at room temperature and annealed with different temperatures (100, 300, 500, 800 and 1100 °C. The biocompatibility of the TiO2 thin films is analyzed using primary cultures of dorsal root ganglion (DRG of Wistar rats, whose neurons are incubated on the TiO2 thin films and on a control substrate during 18 to 24 h. These neurons are activated by electrical stimuli and its ionic currents and action potential activity recorded. Through X-ray diffraction (XRD, the surface of TiO2 thin films showed a good quality, homogeneity and roughness. The XRD results showed the anatase to rutile phase transition in TiO2 thin films at temperatures between 500 and 1100 °C. This phase had a grain size from 15 to 38 nm, which allowed a suitable structural and crystal phase stability of the TiO2 thin films for low and high temperature. The biocompatibility experiments of these films indicated that they were appropriated for culture of living neurons which displayed normal electrical behavior.

  10. Photoinduced superhydrophilicity of TiO2 thin film with hierarchical Cu doping

    Directory of Open Access Journals (Sweden)

    Zhifeng Liu, Yun Wang, Xinli Peng, Yabin Li, Zhichao Liu, Chengcheng Liu, Jing Ya and Yizhong Huang

    2012-01-01

    Full Text Available Hydrophilic Cu–TiO2 thin films with a gradient in the Cu concentration were prepared on glass by layer-by-layer dip-coating from TiO2 precursors. The effects of the Cu doping on the structure and properties of TiO2 self-cleaning thin films are discussed. The Cu gradient markedly affects the hydrophilicity of the films, with the water contact angle significantly reduced compared with those of the pure or uniformly doped TiO2 thin films. This enhanced hydrophilicity is explained by the more efficient absorption of the solar light and by the reduced recombination of photoexcited electrons and holes in the TiO2 films containing a gradient of Cu dopants.

  11. Micropatterning of TiO2 Thin Films by MOCVD and Study of Their Growth Tendency

    Science.gov (United States)

    Hwang, Ki-Hwan; Kang, Byung-Chang; Jung, Duk Young; Kim, Youn Jea; Boo, Jin-Hyo

    2015-01-01

    In this work, we studied the growth tendency of TiO2 thin films deposited on a narrow-stripe area (<10??m). TiO2 thin films were selectively deposited on OTS patterned Si(100) substrates by MOCVD. The experimental data showed that the film growth tendency was divided into two behaviors above and below a line patterning width of 4??m. The relationship between the film thickness and the deposited area was obtained as a function of f(x) = a[1 ? e(?bx)]c. To find the tendency of the deposition rate of the TiO2 thin films onto the various linewidth areas, the relationship between the thickness of the TiO2 thin film and deposited linewidth was also studied. The thickness of the deposited TiO2 films was measured from the alpha-step profile analyses and cross-sectional SEM images. At the same time, a computer simulation was carried out to reveal the relationship between the TiO2 film thickness and deposited line width. The theoretical results suggest that the mass (velocity) flux in flow direction is directly affected to the film thickness. PMID:25799219

  12. Preparation and antibacterial behavior of Fe3+-doped nanostructured TiO2 thin films

    International Nuclear Information System (INIS)

    Fe3+-doped nanostructured TiO2 thin films with antibacterial activity were prepared on soda-lime-silica glass slides by using sol-gel technology. Water containing Escherichia coli K-12 with TiO2 thin films in was exposed to low intensity fluorescent light and antibacterial efficiency was evaluated with spread plate techniques. The films are porous and have anatase phase. Iron ions increased luminous energy utilization as the absorption edge of the Fe3+-doped film has a red shift compared to that of the pure TiO2 film in the UV-VIS absorption spectrum. The bacterial removal efficiency reached 95% at the optimum concentration of iron ion (about 0.5% (mol)) after 120 min irradiation. The antibacterial behavior of the doped TiO2 films was explicitly observed using scanning electron microscopy and cell wall damage was found

  13. Temperature dependence of gas sensing behaviour of TiO2 doped PANI composite thin films

    International Nuclear Information System (INIS)

    In the present work we have reported the effect of temperature on the gas sensing properties of TiO2 doped PANI composite thin film based chemiresistor type gas sensors for hydrogen gas sensing application. PANI and TiO2 doped PANI composite were synthesized by in situ chemical oxidative polymerization of aniline at low temperature. The electrical properties of these composite thin films were characterized by I-V measurements as function of temperature. The I-V measurement revealed that conductivity of composite thin films increased as the temperature increased. The changes in resistance of the composite thin film sensor were utilized for detection of hydrogen gas. It was observed that at room temperature TiO2 doped PANI composite sensor shows higher response value and showed unstable behavior as the temperature increased. The surface morphology of these composite thin films has also been characterized by scanning electron microscopy (SEM) measurement

  14. TiO2 thin-films on polymer substrates and their photocatalytic activity

    International Nuclear Information System (INIS)

    We have developed dip-coating process for TiO2-thin film on polymer substrates (acrylonitrile-butadiene-styrene polymer: ABS, polystyrene: PS). At first, a monodispersed and transparent TiO2 nano-sol solution was prepared by the controlled hydrolysis of titanium iso-propoxide in the presence of acetylacetone and nitric acid catalyst at 80 deg. C. Powder X-ray diffraction patterns of the dried particles are indicative of crystalline TiO2 with anatase-type structure. According to the XRD and transmission electron microscopy (TEM) studies, the mean particle size was estimated to be ca. 5 nm. The transparent thin films on ABS and PS substrates were fabricated by dip-coating process by changing the processing variables, such as the number of dip-coating and TiO2 concentration in nano-sol solution. Scanning electron microscopic (SEM) analysis for the thin film samples reveals that the acetylacetone-modified TiO2 nano-sol particles are effective for enhancing the interfacial adherence between films and polymeric substrates compared to the unmodified one. Photocatalytic degradation of methylene blue (MB) on the TiO2 thin-films has also been systematically investigated

  15. Photocatalytic properties of nanocrystalline TiO2 thin film with Ag additions

    International Nuclear Information System (INIS)

    In the present study, nanocrystalline TiO2/Ag composite thin films were prepared by a sol-gel spin coating technique. While, by introducing polystyrene (PS) microspheres, porous TiO2/Ag films were obtained after calcining at a temperature of 500 oC. The as-prepared TiO2 and TiO2/Ag thin films were characterized by X-ray diffractometry, and scanning electron microscopy to reveal the structural and morphological differences. In addition, the photocatalytic properties of these films were investigated by degrading methylene blue under UV irradiation. After 500 oC calcination, the microstructure of PS-TiO2 film without Ag addition exhibited a sponge-like microstructure while significant sintering effect was noticed with Ag additions and the films exhibited a porous microstructure. Meanwhile, coalescence of nanocrystalline anatase-phase TiO2 can be observed with respect to the sharpening of XRD diffraction peaks. The photodegradation of porous TiO2 doped with 1 mol% Ag exhibited the best photocatalytic efficiency where 72% methylene blue can be decomposed after UV exposure for 12 h

  16. Raman spectra of TiO2 thin films deposited electrochemically and by spray pyrolysis

    International Nuclear Information System (INIS)

    In this paper we present our experimental results concerning the fabrication of TiO2 thin films by spray pyrolysis and electrochemical deposition method onto different substrates - Corning glass, Si and optical fibers. The surface morphology of the TiO2 thin films have been investigated by Atomic Force Microscopy. Raman shift spectra measurements have been done for the optical characterization of the fabricated titania thin films. The post-growth rapid photothermal processing (RPP) at temperatures of 100-800 degrees Celsius for 1-3 min have been applied. Our experimental results prove that by the application of post-growth RPP is possible to essentially improve the crystallinity of the deposited TiO2 films. (authors)

  17. Optical properties of TiO2-MnO2 thin films prepared by electron-beam evaporation

    Science.gov (United States)

    Brus, V. V.; Kovalyuk, Z. D.; Maryanchuk, P. D.

    2012-08-01

    The optical constants and thickness of TiO2-MnO2 films (with MnO2 concentration of 0, 1, and 5%) prepared by electron-beam evaporation are determined. A considerable dependence of the optical properties of thin TiO2 films on the manganese concentration is observed. It is found that thin films are indirect gap semiconductors with gap width E g = 3.43 eV (TiO2), 2.89 eV (TiO2-MnO2 (1%)), and 2.73 eV (TiO2-MnO2 (5%)).

  18. Fabrication of TiO2 thin film memristor device using electrohydrodynamic inkjet printing

    International Nuclear Information System (INIS)

    In this paper, we are reporting the fabrication of memristor device (Ag/TiO2/Cu) using electrohydrodynamic inkjet printing technology. The titanium oxide (TiO2) active layer was deposited using electrohydrodynamic atomization technique. The metal electrodes were patterned by using electrohydrodynamic printing technique. The crystalline nature, surface morphology and optical properties of as deposited TiO2 films were characterized using X-ray diffraction (XRD), scanning electron microscope (SEM) and UV-visible spectroscopic analysis respectively. XRD and SEM studies revealed that the presence of anatase TiO2 with uniform deposition. The optical transmittance of the deposited TiO2 films was observed to be 87% in the visible region. The fabricated memristor device (Ag/TiO2/Cu) exhibits bipolar resistive switching behavior within the low operating voltage (± 0.7 V). Our results ensure that the printed technology provides breakthrough solution in the electronic memory device fabrication. - Highlights: ? Electrohydrodynamic inkjet technique was used to fabricate memristor device. ? The active layer TiO2 presence in the form of anatase. ? The optical transmittance of the TiO2 films was 87% in the visible region. ? Uniform deposition of TiO2 thin film was achieved. ? The Ag/TiO2/Cu device exhibited a bipolar resistive switching behavior.g behavior.

  19. Preparation and Photocatalytic Activity of TiO2 Thin Films on Al Alloys

    Directory of Open Access Journals (Sweden)

    CAI Qian, WANG Jin-Shu, LI Hong-Yi, LIU Shao-Lin, LI Yu-Mei

    2012-06-01

    Full Text Available Using anodized 6061 aluminum alloy and pure aluminum as the templates, TiO2 thin films were prepared through a liquid deposition method. The TiO2 thin film fabricated on the 6061 aluminum alloy substrates appears as bamboo―like structures with holes, whereas that prepared on anodized pure aluminum substrate has one―dimensional tubular structures. The main reason is that magnesium in aluminum alloy is oxidized to form magnesium oxide which has a lower volume than that of Al2O3. The photocatalytic ability of the TiO2 films prepared on the aluminum alloy is superior to that of the films fabricated on the pure aluminum. TiO2 prepared on aluminum alloy has higher specific surface area due to its bamboo―like structures with holes, leading to better performance in the degradation of methylene blue. The photocatalytic performance of the TiO2 by the degradation of aqueous methylene blue is in accordance with the first kinetic equation. TiO2 films deposited in 0.1 mol/L (NH4) TiF6 solution obtain the best photocatalytic performance at apparent reaction rate of 0.00444/min.

  20. XAS study of the local environment of impurities in doped TiO2 thin films

    CERN Document Server

    Torres, C E R; Errico, L A; Duhalde, S; Renter'ia, M; Golmar, F; S'anchez, F H

    2007-01-01

    In this work we present an X-ray Absorption Spectroscopy characterization of the local environment of the impurity in room temperature ferromagnetic anatase TiO2 thin films doped with Co, Ni, Cu, or Zn, deposited on LaAlO3 substrate by Pulsed Laser Deposition. It was found that there is a considerable amount of impurity atoms substituting Ti in TiO2 anatase, although the presence of metal transition monoxide clusters can not be discarded. From our results we infer that the observed room temperature ferromagnetism of the samples could be assigned to the metal transition atoms replacing Ti in TiO2 anatase.

  1. Visible-light photocatalytic activity of nitrided TiO2 thin films

    International Nuclear Information System (INIS)

    TiO2 thin films have been applied in UV-light photocatalysis. Nevertheless visible-light photocatalytic activity would make this material more attractive for applications. In this work we present results on the modification of titanium oxide (anatase) sol-gel thin films, via a nitriding process using a microwave plasma source. After the treatment in the nitrogen plasma, the nitrogen content in the TiO2 films varied in the range from 14 up to 28 at%. The titanium oxide films and the nitrided ones were characterized by XPS, micro-Raman spectroscopy and UV-vis spectroscopy. Photocatalytic activity tests were done using a Methylene Blue dye solution, and as catalyst TiO2 and nitrided TiO2 films. The irradiation of films was carried out with a lamp with emission in the visible (without UV). The results showed that the nitrided TiO2 films had photocatalytic activity, while the unnitrided films did not.

  2. Photoelectrocatalytic degradation of benzoic acid using Au doped TiO2 thin films.

    Science.gov (United States)

    Mohite, V S; Mahadik, M A; Kumbhar, S S; Hunge, Y M; Kim, J H; Moholkar, A V; Rajpure, K Y; Bhosale, C H

    2015-01-01

    Highly transparent pure and Au doped TiO2 thin films are successfully deposited by using simple chemical spray pyrolysis technique. The effect of Au doping onto the structural and physicochemical properties has been investigated. The PEC study shows that, both short circuit current (Isc) and open circuit voltage (Voc) are (Isc=1.81mA and Voc=890mV) relatively higher at 3at.% Au doping percentage. XRD study shows that the films are nanocrystalline in nature with tetragonal crystal structure. FESEM images show that the film surface covered with a smooth, uniform, compact and rice shaped nanoparticles. The Au doped thin films exhibit indirect band gap, decreases from 3.23 to 3.09eV with increase in Au doping. The chemical composition and valence states of pure and Au doped TiO2 films are studied by using X-ray photoelectron spectroscopy. The photocatalytic degradation effect is 49% higher in case 3at.% Au doped TiO2 than the pure TiO2 thin film photoelectrodes in the degradation of benzoic acid. It is revealed that Au doped TiO2 can be reused for five cycles of experiments without a requirement of post-treatment while the degradation efficiency was retained. PMID:25550120

  3. Nanostructured TiO2 thin film memristor using hydrothermal process

    International Nuclear Information System (INIS)

    Highlights: • Nanostructured TiO2 thin film memristor. • Hydrothermal growth process. • Mechanism for the resistive switching behavior. • XRD, Raman, AFM, Reflectance of TiO2 thin film. - Abstract: Fabrication of memristor device (Ag/TiO2/Al) with TiO2 active layer using hydrothermal process is reported. The structural, surface morphological and optical properties of deposited TiO2 films are characterized using X-ray diffraction (XRD), Raman, Atomic force microscope (AFM) and spectroscopic reflectometer techniques respectively. XRD and AFM studies revealed the presence of nanostructured anatase TiO2 with tetragonal crystal structure. The optical reflectance of the deposited TiO2 films is observed to be 15–22% in the visible region. The bipolar resistive switching behavior within the low operating voltage (±0.68 V) is observed in prepared Ag/TiO2/Al memristor. Our results confirm that the hydrothermal route provides breakthrough elucidation in the electronic memory device fabrication. A possible mechanism for the resistive switching behavior has discussed

  4. Room temperature ferromagnetism in vacuum-annealed TiO2 thin films

    International Nuclear Information System (INIS)

    Thin films of pure TiO2 have been prepared using both spin-coating and sputter-deposition techniques on sapphire and quartz substrates. The structural characteristics of the films have been investigated in detail using Raman spectroscopy and high-resolution transmission electron microscopy (HRTEM). When annealed in vacuum, all films demonstrate room temperature ferromagnetism, while the air-annealed samples show much smaller, often negligible, magnetic moments. The magnetization of the vacuum-annealed sputtered samples depends on film thickness, with the volume magnetization decreasing monotonically with increasing thickness. Furthermore, the magnetization per unit area also decreases slightly with increasing film thickness. These results suggest that ferromagnetism in the vacuum-annealed TiO2 films is mediated by surface defects or interfacial effects, but does not arise from stoichiometric crystalline TiO2

  5. Chromium doped TiO2 sputtered thin films synthesis, physical investigations and applications

    CERN Document Server

    Hajjaji, Anouar; Gaidi, Mounir; Bessais, Brahim; El Khakani, My Ali

    2014-01-01

    This book presents co-sputtered processes ways to produce chrome doped TiO2 thin films onto various substrates such as quartz, silicon and porous silicon. Emphasis is given on the link between the experimental preparation and physical characterization in terms of Cr content. Moreover, the structural, optical and optoelectronic investigations are emphasized throughout. The book explores the potencial applications of devices based on Cr doped TiO2 thin films as gas sensors and in photocatalysis and in the photovoltaic industry. Also, this book provides extensive leads into research literature,

  6. Synthesis of Structured Macroporous TiO2 Thin Films and Investigation on Their Photocatalytic Activities

    International Nuclear Information System (INIS)

    Synthesis of structured macroporous TiO2 thin films on quartz substrate (macro-TiO2/Q) was performed by a dip-coating method using poly(methyl methacrylate) (PMMA) microspheres as template. Obtained TiO2 thin films kept high transparency and had anatase crystalline structure. SEM observations revealed that the macropores were uniformly formed on the film surface. The size of macropores was quite similar to the diameter of PMMA microspheres as template. In comparison to the nonporous TiO2 thin films (TiO2/Q), macro-TiO2/Q exhibited twice higher photocatalytic activity for decolorization of methylene blue in water. Decomposition of acetaldehyde in gas phase also proceeded efficiently on macro-TiO2/Q. Moreover, the surface of macro-TiO2/Q was easily hydrophilized after a short period of UV light irradiation and maintained lower water contact angle in the dark for a long period as compared to those of TiO2/Q.

  7. Oblique angle deposition of TiO2 thin films prepared by electron-beam evaporation

    International Nuclear Information System (INIS)

    Optical, structural and photocatalytic properties of TiO2 thin films obliquely deposited on quartz glass substrate using an electron-beam evaporation method were investigated. The photocatalytic activity of the films was evaluated by photodecomposition of methylene blue. An increase in incident deposition angle increased the porosity and surface roughness of the TiO2 films. As a result, the photocatalytic activity was enhanced with incident deposition angle up to 60 deg. However, a further increase in incident deposition angle to 75 deg. reduced the photocatalytic activity due to a lack of the crystalline phase.

  8. Porous nanocrystalline TiO2 thin films for dye-sensitized solar cells

    Science.gov (United States)

    Fan, Xiaojuan; Swanson, Claudia; Rogow, David; Tripathi, Akhilesh; Oliver, Scott

    2008-03-01

    We report a rapid and low cost method to fabricate porous TiO2 thin films used as anode electrodes for solid state dye-sensitized solar cells. Polymethylmethacrylate (PMMA) gel was used as template to define a network co-structure with alkali titanium oxide, then spin cast on substrates. After thermally removing polymer, smooth and crack-free large area TiO2 thin films with fine pores were generated. Thin film structures were detected by powder & grazing incident X-ray diffraction. Film thickness can be controlled over a range of tens of nanometers to several microns by precursor viscosity, spin coating speed and coating times. The SEM image shows the highest quality porous TiO2 film derived from a certain concentration of precursor. The above TiO2 thin films were then used to fabricate solid state dye sensitized solar cells. Porphyrine dye and poly(ethylene glycol) electrolyte with I^-/I3^- redox couple were used in the cells. Current-voltage curves were recorded. The open circuit voltage boosts to more than 1.0 V. The reasons for the high open circuit voltage probably will be discussed. Overall photo-electricity conversion efficiency reaches 2.05% under an illumination of one solar unit (AM1.5, 100 mW/cm^2).

  9. Mn-doped TiO2 thin films with significantly improved optical and electrical properties

    Science.gov (United States)

    Lu, Liu; Xia, Xiaohong; Luo, J. K.; Shao, G.

    2012-12-01

    TiO2 thin films with various Mn doping contents were fabricated by reactive magnetron sputtering deposition at 550 °C and their structural, optical and electrical properties were characterized. All films were made of densely packed columnar grains with a fibrous texture along the normal direction of the substrate. The as-deposited structure in the pure TiO2 film consisted of anatase grains with the [1?0?1] texture. Mn incorporation stabilized the rutile phase and induced lattice contraction in the [1?0?0] direction. The texture in the Mn-doped films changed from [1?1?0] to [2?0?0] with increasing Mn content. The incorporation of Mn in the TiO2 lattice introduced intermediate bands into its narrowed forbidden gap, leading to remarkable red-shifts in the optical absorption edges, together with significantly improved electrical conductivity of the thin films. Hall measurement showed that the incorporation of Mn-induced p-type conductivity, with hole mobility in heavily doped TiO2 (˜40% Mn) being about an order higher than electron mobility in single-crystal rutile TiO2. Oxygen vacancies, on the other hand, interacted with substitutional Mn atoms to reduce its effect on optical and electrical properties.

  10. Obtenção de filmes finos de TiO2 nanoestruturado pelo método dos precursores poliméricos / Nanostructured TiO2 thin films by polymeric precursor method

    Scientific Electronic Library Online (English)

    Daniel Grando, Stroppa; Tania Regina, Giraldi; Edson Roberto, Leite; José Arana, Varela; Elson, Longo.

    1706-17-01

    Full Text Available [...] Abstract in english This work focuses in optimizing setup for obtaining TiO2 thin films by polymeric precursor route due to its advantages on stoichiometric and morphological control. Precursor stoichiometry, synthesis pH, solids concentration and rotation speed at deposition were optimized evaluating thin films morpho [...] logy and thickness. Thermogravimetry and RMN were applied for precursor's characterization and AFM, XRD and ellipsometry for thin films evaluation. Results showed successful attainment of homogeneous nanocrystalline anatase TiO2 thin films with outstanding control over morphological characteristics, mean grain size of 17 nm, packing densities between 57 and 75%, estimated surface areas of 90 m²/g and monolayers thickness within 20 and 128 nm.

  11. Fabrication of TiO2 nanotubes by anodization of Ti thin films for VOC sensing

    International Nuclear Information System (INIS)

    Ti thin films were anodized in aqueous HF (0.5 wt.%) and in polar organic (0.5 wt.% NH4F + ethylene glycol) electrolytes to form TiO2 nanotube arrays. Ti thin films were deposited on microscope glass substrates and then anodized. Anodization was performed at potentials ranging from 5 V to 20 V for the aqueous HF and from 20 V to 60 V for the polar organic electrolytes over the temperatures range from 0 to 20 °C. The TiO2 nanotubes were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX). It has been observed that anodization of the deposited Ti thin films with aqueous HF solution at 0 °C resulted in nanotube-type structures with diameters in the range of 30–80 nm for an applied voltage of 10 V. In addition, the nanotube-type structure is observed for polar organic electrolyte at room temperature at the anodization voltage higher than 40 V. The volatile organic compound (VOC) sensing properties of TiO2 nanotubes fabricated using different electrolytes were investigated at 200 °C. The maximum sensor response is obtained for carbon tetrachloride. The sensor response is dependent on porosity of TiO2. The highest sensor response is observed for TiO2 nanotubes which are synthesized using aqueous HF electrolyte and have very high porosity.

  12. Characterization of TiO2 Thin Films on Glass Substrate Growth Using DC Sputtering Technique

    International Nuclear Information System (INIS)

    It has been fabricated and characterization a TiO2 thin films deposited on glass substrate using DC sputtering technique. Fabrication of TiO2 thin films were carried out at electrode voltage 4 kV, sputtering current 5 mA, vacuum pressure 5 x 10-4 torr, deposition time 150 minutes, and temperature of the substrate were varied from 150 -350 oC, while as a gas sputter was argon. The results was tested their micro structure using SEM, and crystal structure using XRD and found that the crystal structure of TiO2 powder before deposited on glass substrate was rutile and anatase with orientation (110) and (200) for anatase and (100) and (111) rutile structure. While the crystal structure which deposited at temperature 150 oC and deposition time 2.5 hours was anatase with orientation (001) and (200). (author)

  13. Self-assembly of ordered mesoporous TiO2 thin films as photoanodes for cathodic protection of stainless steel

    International Nuclear Information System (INIS)

    Highlights: ? The ordered mesoporous TiO2 thin films were prepared on FTO substrates. ? The more effective photocathodic protection was observed for mesoporous TiO2 films. ? More negative photopotential was observed for 500 °C-calcined mesoporous TiO2 film. ? The larger photocurrent was observed for mesoporous TiO2 film calcined at 500 °C. - Abstract: In this paper, the ordered mesoporous TiO2 thin films that served as photoanodes for cathodic protection of SUS304 stainless steel (304SS) were prepared through the sol–gel and evaporation-induced self-assembly method. The as-prepared TiO2 thin films were calcined at 350 °C and 500 °C, and then characterized by scanning electron microscopy (SEM), the small-angle X-ray diffraction (SAXD) as well as the wide-angle X-ray powder diffraction (WAXD). Moreover, the photoelectrochemical properties of the mesoporous TiO2 thin films such as the open circuit potential (OCP), the photocurrent spectra as well as the Tafel polarization curves were also measured. The results showed that the more negative photopotential was observed for the mesoporous TiO2 films compared to the TiO2 films without mesoporous structures. Besides, the mesoporous TiO2 films calcined at 500 °C exhibited the more negative photopotential and larger photocurrent than that calcined at 350 °C. In conclusion, the mesoporous TiO2 esoporous TiO2 films could provide the effective photogenerated cathodic protection for 304SS.

  14. Effect of Au Nanoparticles Doping on The Properties of TiO2 Thin Films

    Directory of Open Access Journals (Sweden)

    Aytaç GÜLTEK?N

    2014-02-01

    Full Text Available In this study, pure and gold (Au nanoparticles doped TiO2 thin films (Au/Ti = 10, 20, 30, 40 and 50 at% were prepared by sol-gel method and the impact of Au nanoparticles doping on the optical, structural and morphological properties of these thin films was examined. All thin films were characterized using ultraviolet-visible-near infrared (UV-Vis-NIR spectrophotometry, X-ray diffraction (XRD, transmission electron microscopy (TEM and atomic force microscopy (AFM. The optical band gap of the thin films increases from 3.74 eV to 3.89 eV with the increase of Au nanoparticles concentrations due to the Moss-Burstein effect. XRD results show that all thin films have cubic poly-crystal structure and the intensities of peaks of the crystalline phase increased with the increase of Au nanoparticles concentrations. The AFM results indicate that the TiO2 thin ?lms are formed from the nanoparticles and the grain size of the ?lms is changed with Au doping level. Consequently, it is shown that the structural, morphological and optical properties of the TiO2 thin ?lms could be changed by Au nanoparticles-doping. DOI: http://dx.doi.org/10.5755/j01.ms.20.1.3709

  15. Magnetic and structural study of Cu-doped TiO2 thin films

    CERN Document Server

    Torres, C E R; Cabrera, A F; Errico, L A; Navarro, A M M; Renter'ia, M; S'anchez, F H; Duhalde, S

    2007-01-01

    Transparent pure and Cu-doped (2.5, 5 and 10 at. %) anatase TiO2 thin films were grown by pulsed laser deposition technique on LaAlO3 substrates. The samples were structurally characterized by X-ray absorption spectroscopy and X-ray diffraction. The magnetic properties were measured using a SQUID. All films have a FM-like behaviour. In the case of the Cu-doped samples, the magnetic cycles are almost independent of the Cu concentration. Cu atoms are forming CuO and/or substituting Ti in TiO2. The thermal treatment in air promotes the CuO segregation. Since CuO is antiferromagnetic, the magnetic signals present in the films could be assigned to this Cu substitutionally replacing cations in TiO2.

  16. Structural, optical and electrochemical properties of TiO2 thin films grown by APCVD method

    International Nuclear Information System (INIS)

    Atmospheric pressure chemical vapor deposition (APCVD) of TiO2 thin films has been achieved onto glass and onto ITO-coated glass substrates, from the reaction of TiCl4 with ethyl acetate (EtOAc). The effect of the synthesis temperature on the optical, structural and electrochemical properties was studied through spectral transmittance, X-ray diffraction (XRD) and electrochemical impedance spectroscopy (EIS) measurements. It was established that the TiO2 films deposited onto glass substrate, at temperatures greater than 400 deg. C grown with rutile type tetragonal structure, whereas the TiO2 films deposited onto ITO-coated glass substrate grown with anatase type structure. EIS was applied as suitable method to determine the charge transfer resistance in the electrolyte/TiO2 interface, typically found in dye-sensitized solar cells.

  17. Low Loss Sol-Gel TiO2 Thin Films for Waveguiding Applications

    OpenAIRE

    Alexis Fischer; Ovidiu Brinza; Iva Ninova-Kuznetsova; Dominique Vrel; Tahar Touam; Lamia Znaidi; Azzedine Boudrioua

    2013-01-01

    TiO2 thin films were synthesized by sol-gel process: titanium tetraisopropoxide (TTIP) was dissolved in isopropanol, and then hydrolyzed by adding a water/isopropanol mixture with a controlled hydrolysis ratio. The as prepared sol was deposited by “dip-coating” on a glass substrate with a controlled withdrawal speed. The obtained films were annealed at 350 and 500 °C (2 h). The morphological properties of the prepared films were analyzed by Scanning Electron Microscopy (SEM) and Atomic F...

  18. The Photocatalytic and Antibacterial Activity of Cu-Doped TiO2 Thin Films

    Directory of Open Access Journals (Sweden)

    Weerachai SANGCHAY

    2013-02-01

    Full Text Available Thin films of TiO2 and TiO2 doped with Cu were prepared by sol-gel method. The prepared films were calcined at the temperature of 400 °C for 2 h with the heating rate of 10 °C/min. Physical properties as well as crystal compositions of the fabricated films were characterized by XRD, EDX SEM and AFM techniques. The results show that all samples have thickness range from 0.25 to 1.0 um. The film surfaces are typically uniform and dense with TiO2 nanoparticles. The photocatalytic activities of the thin films were also tested via the degradation of methylene blue (MB solution under UV irradiation. Finally, antibacterial activity efficiency was evaluated by the inactivation of E.coli. It was observed that higher Cu concentration gives better photocatalytic activity. With the highest dopant concentration investigated in this experiment (TiO2-1.0Cu condition the films show photocatalytic of 70 % and antibacterial activity of 100 %.

  19. Thin films of TiO2:N for photo-electrochemical applications.

    Science.gov (United States)

    Trenczek-Zajac, A; Pamula, E; Radecka, M; Kowalski, K; Reszka, A; Brudnik, A; Kusior, E; Zakrzewska, K

    2012-06-01

    Dc-pulsed magnetron sputtering from Ti target in reactive Ar+O2+N2 atmosphere was used to grow stoichiometric TiO2:N and non-stoichiometric TiO2-x:N thin films. X-ray diffraction at glancing incidence, atomic force microscopy AFM, scanning electron microscopy SEM, X-ray photoelectron spectroscopy XPS, and optical spectrophotometry were applied for sample characterization. Measurements of photocurrent versus voltage and wavelength over the ultraviolet uv and visible vis ranges of the light spectrum were performed in order to assess the performance of nitrogen-doped titanium dioxide thin films as photoanodes for hydrogen generation in photoelectrochemical cells, PEC. Undoped TiO2 and TiO2-x films were found to be composed of anatase and rutile mixture with larger anatase crystallites (25-35 nm) while the growth of smaller rutile crystallites (6-10 nm) predominated at higher nitrogen flow rates etaN2 as measured in standard cubic centimeters, sccm. Nitrogen-to-titanium ratio increased from N/Ti = 0.05 at etaN2 = 0.8 sccm for stoichiometric TiO2:N to N/Ti = 0.11 at etaN2 = 0.8 sccm for nonstoichiometric TiO2-x:N thin films. A red-shift in the optical absorbance was observed with an increase in etaN2. Doping with nitrogen improved photoelectrochemical properties over the visible range of the light spectrum in the case of nonstoichiometric samples. PMID:22905519

  20. Antibacterial and Photodegradative Properties of Metal Doped TiO2 thin Films Under Visible Light.

    Science.gov (United States)

    Ogorevc, Jerneja Šauta; Tratar-Pirc, Elizabeta; Matoh, Lev; Peter, Bukovec

    2012-06-01

    Doped (Au, Ag) and undoped TiO2 thin films were prepared on soda-lime glass via the sol-gel method by dip-coating from TiCl4 precursor, followed by 30 minutes calcination at 500 °C to obtain transparent thin films with good adhesion to the substrate. XRD analysis showed that the particle size of samples heat treated at 500 °C was ~10 nm for all of the samples prepared, both doped and undoped ones. SEM images revealed that the thin film surface was homogeneous and nano-porous. The hydrophilicity of the thin films was estimated by contact angle measurements. The photodegradation rate of an aqueous solution of the azo dye Plasmocorinth B on the thin films was tested by in-situ UV-Vis spectroscopic measurements of the dye solution. The best photocatalytic activity under visible and UVA light was exhibited by undoped TiO2 thin films, whereas Au doped thin films were slightly less active. On the other hand, the best antimicrobial activity toward the E. coli strain DH5a under visible light was displayed by the Au/TiO2 thin films. PMID:24061239

  1. Structural Analysis of RF Sputtered TiO2 Thin Film on Cu Substrate for Various Annealing Temperatures

    Directory of Open Access Journals (Sweden)

    Shanmugan S

    2014-08-01

    Full Text Available The structural parameters of RF sputtered TiO2 thin film deposited on Cu substrates was tested using XRD spectra. Prepared TiO2 thin film was polycrystalline nature with the mixture of cubic, orthorhombic and tetragonal phases. Orthorhombic phase was preferentially grown on Cu substrate. The crystallite size of the TiO2 thin film was varied depends on the orientations and overall decreased crystallite size was noticed upto 300 °C. The observed residual stress was compressive nature as dominated at all temperature other than 400°C. Crystal defects such as dislocation density was high for cubic phase of TiO2 at higher annealing temperature. Overall, the annealing temperatures influenced the structural parameters with respect to the observed orientations of TiO2 thin film on Cu substrates.

  2. Photocatalytic property of TiO2 thin films sputtered-deposited on unheated substrates

    International Nuclear Information System (INIS)

    TiO2 films deposited on unheated substrates of alumina silicate glass by rf. (13.56 MHz) magnetron sputtering in the mixture of O2 and Ar gases have been studied with X-ray diffraction (XRD), Atomic Force Microscopy (AFM) and optical spectroscopy. Structural and optical properties of TiO2 films deposited at different O2 concentrations and total pressures have been analyzed. Photocatalytic properties of TiO2 films were characterized by following the degradation of methylene blue molecules under UV irradiation. It was found that the rate of methylene blue decomposition strongly depends on morphology and crystallinity of the deposited films, namely on the content of the anatase phase and on the size of the anatase grains. The best photocatalytic activity was found on TiO2 films consisting of pure anatase phase with the size of grains of about 450 A. With the help of those films a thin film reactor for water purification has been designed and tested.

  3. Resistive switching of oxygen enhanced TiO2 thin-film devices

    Science.gov (United States)

    Salaoru, Iulia; Prodromakis, Themistoklis; Khiat, Ali; Toumazou, Christofer

    2013-01-01

    In this work, we investigate the effect of oxygen-enhanced TiO2 thin films on the switching dynamics of Pt/TiO2/Pt memristive nanodevices. We demonstrate that such devices can be used as resistive random access memory (RRAM) cells without required electroforming. We experimentally demonstrate that devices based on TiO2 films fabricated via sputtering with partial pressures of Ar/O2 6/6 sccm and 2/10 sccm show OFF/ON ratios of six and two orders of magnitude, respectively. Additionally, it was found that a lower O2 flow during sputtering of TiO2 allows for lower energy requirements for switching the devices from a high to low resistive state.

  4. RBS analysis of substoichiometric TiO2-anatase thin films for visible-light photocatalysis

    International Nuclear Information System (INIS)

    The anatase phase of TiO2 is the most promising photocatalyst for organic pollutants degradation. However, due to the large anatase band gap energy the possibility of using visible sunlight as energy source for the photocalatysis activation is ruled out and ultraviolet (UV) radiation with a wave length below the critical limit is thus required. Inducing defects in the anatase crystalline structure in the form of oxygen substoichiometry may theoretically reduce this large band gap energy. This paper focuses on the determination of the stoichiometry of TiO2 thin films and its influence on the photodegradation properties

  5. Photocatalytic activity of pulsed laser deposited TiO2 thin films

    International Nuclear Information System (INIS)

    Nanostructured TiO2 thin films were prepared by pulsed laser deposition (PLD) on indium-doped tin oxide (ITO) substrates. Results from X-ray photoelectron spectroscopy (XPS) show that Ti 2p core level peaks shift toward the lower binding energy with decrease in the buffer gas pressure (O2:Ar = 1:1). This suggests that oxygen vacancies are created under insufficient oxygen conditions. Anatase-to-rutile ratio is also found to be system pressure dependent. Under deposition pressure of 100 Pa, only anatase phase was observed even at 1073 K substrate temperature which is much higher that the bulk anatase-to-rutile phase transformation temperature. The deposited TiO2 thin films were fabricated as photoanodes for photoelectrochemical (PEC) studies. PEC measurements on TiO2 photoanodes show that the flatband potential (Vfb) increases by 0.088 eV on absolute vacuum energy scale (AVS) with decrease in the deposition pressure from 100 to 33 Pa at 873 K. The highest incident photon to current conversion efficiency [IPCE(?)] of 2.5 to 6% at ? = 320 nm was obtained from the thin films prepared at substrate temperature of 873 K. Combining the results from XPS and PEC studies, we conclude that the deposition pressure affects the concentration of the oxygen vacancies which changes the electronic structure of the TiO2. With reference to photoelectrochemical catalytic performance, our results suggest that it is possible our results suggest that it is possible to adjust the Fermi energy level and structure of TiO2 thin films by controlling the buffer gas pressure and temperature to align the energy of the flatband potential (Vfb) with respect to specific redox species in the electrolyte

  6. Low Loss Sol-Gel TiO2 Thin Films for Waveguiding Applications

    Directory of Open Access Journals (Sweden)

    Alexis Fischer

    2013-03-01

    Full Text Available TiO2 thin films were synthesized by sol-gel process: titanium tetraisopropoxide (TTIP was dissolved in isopropanol, and then hydrolyzed by adding a water/isopropanol mixture with a controlled hydrolysis ratio. The as prepared sol was deposited by “dip-coating” on a glass substrate with a controlled withdrawal speed. The obtained films were annealed at 350 and 500 °C (2 h. The morphological properties of the prepared films were analyzed by Scanning Electron Microscopy (SEM and Atomic Force Microscopy (AFM. The optical waveguiding properties of TiO2 films were investigated for both annealing temperature using m-lines spectroscopy. The refractive indices and the film thickness were determined from the measured effective indices. The results show that the synthesized planar waveguides are multimodes and demonstrate low propagation losses of 0.5 and 0.8 dB/cm for annealing temperature 350 and 500 °C, respectively.

  7. Effects of heat treatment and TiO2 content on the optical properties of Eu3+ doped TiO2–SiO2 thin films

    International Nuclear Information System (INIS)

    The photoluminescence properties of Eu3+-doped TiO2–SiO2 thin films were investigated. The films were deposited on silicon substrates by the sol–gel process using the dip-coating method. The molar ratio of TiO2 content was varied from 25% to 100%, while Europium concentration was fixed to 1%. The obtained films were calcinated at various temperatures ranging from 400 °C to 1300 °C, which allowed determining the optimal conditions for the Eu3+ luminescence. Meanwhile, the structure of TiO2–SiO2 powders, prepared in the same conditions as the films, was also studied by Raman spectroscopy. It revealed the role of Europium and SiO2 on the stabilization of the anatase phase and the importance of the silica matrix in the control of titania particle size. - Highlights: ? Eu3+ doped TiO2–SiO2 thin films and powders have been prepared by the sol–gel method. ? Film thickness and refractive index depend on both Ti concentration and heat-treatment temperature. ? The Eu3+ emission increases with TiO2 concentration. ? The PL intensity begins to increase before decreasing for temperatures higher than 600 °C.

  8. TiO2 thin films using organic liquid materials prepared by Hot-Wire CVD method

    International Nuclear Information System (INIS)

    TiO2 thin films prepared by Hot-Wire CVD method have been studied as a protecting material of transparent conducting oxide (TCO) against atomic hydrogen exposures for the fabrications of Si thin film solar cells. It was found that electrical conductivity of the films at room temperature reached a value of 0.4 S/cm. This value is 2-3 orders of magnitude higher than that of TiO2 films prepared by RF magnetron sputtering and electron-beam evaporation methods in our previous works. The conductivity improvement seems to be partly due to the enlargement of TiO2 crystallites

  9. Ferromagnetism in doped TiO2 thin films prepared by PLD

    International Nuclear Information System (INIS)

    Transition-Metal-doped TiO2 thin films, with nominal composition Ti0.9TM0.1O2-? (TM = Mn, Fe, Co, Ni, Cu), were grown by pulsed laser deposition (PLD), in order to study the role of dopants in the origin and significance of room temperature ferromagnetism in these systems. The crystallographic structures and their magnetic properties were characterized and the experimental results are compared to ab-initio calculations previously reported. The films are ferromagnetic at room temperature in the cases of Fe, Co, Ni and even Cu impurities, but not in the case of Mn doping. Our results support the hypothesis that oxygen vacancies play a key role in the origin of magnetism in doped TiO2 films, and can explain the diversity of magnetic moments observed experimentally for films grown under different conditions

  10. Nano-scaled photocatalytic TiO2 thin films prepared by magnetron sputtering

    International Nuclear Information System (INIS)

    Reactive r.f. magnetron sputtering was used as a PVD method for the deposition of photocatalytic TiO2 transparent films on glass substrate. X-ray diffraction, scanning electron microscopy and the measurement of the photocatalytic activity by the decomposition of methylene blue were applied for the film characterisation. The TiO2 films with the anatase structure and a variable film thickness ranging from 70 to 950 m were deposited on stationary substrate at two values of the total pressure with a goal to investigate their photocatalytic activity. It was found that the photocatalytic activity increases with increasing film thickness only if the films are prepared at higher sputtering pressures. Furthermore, 65 nm thick TiO2 films were deposited on rotating substrate and the relationship between the deposition parameters, such as the substrate temperature and the total pressure, the structure and the photocatalytic activity was studied. These thin films showed a very good photocatalytic activity when an appropriate substrate temperature (>100 deg. C) and/or total pressure (>1 Pa) are selected

  11. Reaction of Ru(II) diazafluorenone compound with nanocrystalline TiO2 thin film.

    Science.gov (United States)

    Heuer, William B; Xia, Hai-Long; Abrahamsson, Maria; Zhou, Zhen; Ardo, Shane; Narducci Sarjeant, Amy A; Meyer, Gerald J

    2010-09-01

    The Ru(II) compounds [Ru(bpy)(2)(mcbH)](2+) and [Ru(bpy)(2)(dafo)](2+), bpy is 2,2'-bipyridine where mcbH is 3-(CO(2)H)-2,2'-bipyridine and dafo is 4,5-diazafluoren-9-one, were synthesized, characterized, and anchored to nanocrystalline mesoporous TiO(2) thin films for excited state and interfacial electron transfer studies. X-ray crystallographic studies of [Ru(bpy)(2)(mcbH)](PF(6))(Cl) revealed a long Ru-N distance to the unsubstituted pyridine ligand of mcbH. Reaction of [Ru(bpy)(2)(dafo)](2+) with TiO(2) thin films resulted in interfacial chemistry. The IR, (1)H NMR, UV-vis, and photoluminescence spectral data indicated a room-temperature ring-opening reaction of the dafo ligand of [Ru(bpy)(2)(dafo)](2+) that ultimately yielded a carboxylate group in the 3-position of bipyridine anchored to TiO(2). Comparative reactions of [Ru(bpy)(2)(mcbH)](2+) with TiO(2) were performed and support this conclusion. In regenerative photoelectrochemical solar cells with 0.5 M LiI/0.05 M I(2) in acetonitrile, photocurrent action spectra were observed for both sensitized materials. The incident photon-to-current efficiency (IPCE) was significantly lower for Ru(bpy)(2)(dafo)/TiO(2), behavior attributed to a lower excited-state injection yield. PMID:20701276

  12. X-ray absorption and emission spectroscopy of TiO2 thin films with modified anionic sublattice

    International Nuclear Information System (INIS)

    Crystallographic and optical properties as well as electronic structure of titanium dioxide thin films with modified anionic sublattice, i.e., non-stoichiometric, undoped and nitrogen doped thin films of TiO2?x and TiO2?x:N, were studied by means of X-ray diffraction, optical spectrophotometry, X-ray absorption and emission spectroscopy. We demonstrate that TiO2?x films undergo a gradual evolution of the crystallographic structure accompanied by the progressive change in interatomic distances with the preserved local symmetry and nearly unchanged effective 3d charge of Ti ions. At a certain degree of oxygen deficit an abrupt change in all the properties studied can be seen. Amorphisation, possible Ti precipitation and increased optical absorption over the visible range correlates well with a significantly higher 3d band occupancy derived from XES for TiO2?x. Thin films of TiO2?x:N demonstrate gradual evolution of the local structure and charge redistribution upon increased level of nitrogen doping. - Highlights: • Thin films of TiO2?x and TiO2?x:N were deposited by dc-pulsed reactive sputtering. • Studies with: XRD, optical spectrophotometry, XAS and XES measurements have been carried out. • TiO2?x shows preserved local symmetry and nearly unchanged effective 3d charge of Ti ions. • At certain degree of oxygen deficit in TiO2?x an abrupt change in all the properties studied is seen. • TiO2?x:N shows a gradual evolution of the local structure and charge from TiO2 to TiN

  13. Bimodal nanostructured TiO2 thin films for dye sensitized solar cells.

    Czech Academy of Sciences Publication Activity Database

    Zukalová, Markéta; Kavan, Ladislav; Zukal, Arnošt; Graetzel, M.

    Málaga : BrownWalker Press, 2012. s. 99-99. ISBN 978-1-61233-558-2. [EMR 2012 : The Energy and Materials Research Conference. 20.06.2012-22.06.2012, Torremolinos] R&D Projects: GA ?R(CZ) GAP108/12/0814 Institutional support: RVO:61388955 Keywords : TiO2 * thin films * dye-sensitized solar cell Subject RIV: CG - Electrochemistry

  14. S180 cell growth on low ion energy plasma treated TiO2 thin films

    International Nuclear Information System (INIS)

    X-ray photoelectron spectroscopy (XPS) was used to characterise the effects of low energy (2 thin films deposited by radio frequency (RF) magnetron sputter system. The low energy argon ion plasma surface modification of TiO2 in a two-stage hybrid system had increased the proportion of surface states of TiO2 as Ti3+. The proportion of carbon atoms as alcohol/ether (C-OX) was decreased with increase the RF power and carbon atoms as carbonyl (C=O) functionality had increased for low RF power treatment. The proportion of C(=O)OX functionality at the surface was decreased at low power and further increase in power has showed an increase in its relive proportion at the surface. The growth of S180 cells was observed and it seems that cells are uniformly spreads on tissue culture polystyrene surface and untreated TiO2 surfaces whereas small-localised cell free area can be seen on plasma treated TiO2 surfaces which may be due to decrease in C(=O)OX, increase in C=O and active sites at the surface. A relatively large variation in the surface functionalities with no change in the surface roughness was achieved by different RF plasma treatments of TiO2 surface whereas no significant change in S180 cell growth with different plasma treatments. This may be because cell growth on TiO2 was mainly influenced by nano-surface characteristics of oxided by nano-surface characteristics of oxide films rather than surface chemistry

  15. Preparation of titanium dioxide porous thin films via photopolymerization of the colloidal TiO2 dispersion

    International Nuclear Information System (INIS)

    Titanium dioxide (TiO2) thin films with porous structures have been successfully achieved by photopolymerization stimulating the particle dispersion combined TiO2 colloid with photoinitiator and monomer. The photopolymerization monomer Pentaerythritol Triacrylate (PETA) and photoinitiator 2-Hydroxy-2-methyl-propiophenone (HMPP) are added to the TiO2 colloidal solution to form the new colloidal TiO2 dispersion. After coating the dispersion on the substrate, the coating is cured with UV light. With the evaporation of solvent and the formation of microgels induced by polymerization, a phase separation occurs in the system. A porous TiO2 film with various pore sizes from mesoporous to macroporous could be produced after heat treatment. The morphology and size of pores could be tuned by changing the process of phase separation, which is controlled by the composition of colloidal TiO2 dispersion. The content of photoinitiator and the temperature of heat treatment were decided by UV–vis absorption spectra and thermal analysis (DTA–TGA), respectively; Real-Time Fourier-transform infrared (RT-FTIR) spectroscopy, scanning electron microscopy (SEM), X-ray diffractometer (XRD) and high-resolution transmission electron microscopy (HR-TEM) were used to characterize the TiO2 films. The as-prepared TiO2 porous films exhibited higher photocatalytic activity for degradation methylene blue in comparison with conventional TiO2 dense film due to its porous structure. - Highlights: • TiO2 porous film was prepared by photopolymerization stimulating particle dispersion. • Colloidal TiO2 dispersion contained photoinitiator and monomer for curing reaction. • The morphology and size of pores were dependent on the composition of dispersion. • The phase separation mechanism occurred during the photopolymerization was proposed. • TiO2 porous films showed high photocatalytic activity

  16. Nanoporous TiO2 thin film based conductometric H2 sensor

    International Nuclear Information System (INIS)

    Nanoporous titanium dioxide (TiO2) based conductometric sensors have been fabricated and their sensitivity to hydrogen (H2) gas has been investigated. A filtered cathodic vacuum arc (FCVA) system was used to deposit ultra-smooth Ti thin films on a transducer having patterned inter-digital gold electrodes (IDTs). Nanoporous TiO2 films were obtained by anodization of the titanium (Ti) thin films using a neutral 0.5% (wt) NH4F in ethylene glycol solution at 5 V for 1 h. After anodization, the films were annealed at 600 oC for 8 h to convert the remaining Ti into TiO2. The scanning electron microscopy (SEM) images revealed that the average diameters of the nanopores are in the range of 20 to 25 nm. The sensor was exposed to different concentrations of H2 in synthetic air at operating temperatures between 100 oC and 300 oC. The sensor responded with a highest sensitivity of 1.24 to 1% of H2 gas at 225 oC.

  17. Water effect on the surface morphology of TiO2 thin film modified by polyethylene glycol

    International Nuclear Information System (INIS)

    Highlights: ? TiO2 porous thin film is fabricated using polyethylene glycol 6000 (PEG-6000) as a template. ? The water molecules provide locations for the aggregation of PEG-6000, and it is demonstrated by the phase diagrams of AFM. ? The water content has an influence on the surface structure and the thin film thickness. ? The TiO2 thin film has the best photocatalytic activity when the ratio of water to Ti precursor is 2. - Abstract: Water effect on the surface morphology of TiO2 thin film was investigated by using PEG-6000 as a template to form the porous structure. The porous TiO2 thin films were characterized by thermo-gravimetric analysis (TGA), X-ray diffraction (XRD), n and k Analyzer, UV–vis spectrophotometer, field-emission scanning electron microscopy (FE-SEM), and atomic forced microscopy (AFM) as a function of water content in the preparation of TiO2 thin film. The various water contents result in the TiO2 thin films possessing different surface structures, grain sizes, and thicknesses. The grain sizes were varied with changing the water content, and the thickness increased with increasing water content due to the enhancement of the cross-linking speed. In addition, the cratered surface structure transformed into cracked surface structure upon the water content beyond stoichiometric quantity because the excess water causes the aggregation of polyethylene glycol (PEG-6000). The phoylene glycol (PEG-6000). The photocatalysis has been performed by the degradation of methyl blue with corresponding structural characteristics of the TiO2 thin film. The best photocatalytic activity has been obtained when the ratio of water to titanium precursor is equal to 2 referred as TiO2-W2.

  18. Pyrosol deposition of anatase TiO2 thin films starting from Ti(OiPr)4/acetylacetone solutions

    OpenAIRE

    Duminica, Florin-Daniel; Maury, Francis; Abisset, Sidonie

    2007-01-01

    TiO2 thin films were deposited on Si(100) and steel substrates by Pyrosol technique. The layer morphology depends on the concentration of titanium tetra-isopropoxide (TTIP) used as molecular precursor in solutions with acetylacetone (Acac). The concentration and, as a result, the viscosity of these TTIP/Acac starting solutions plays an important role on the efficiency of their nebulization and, consequently, on the microstructure and the growth kinetics of the TiO2 thin films. The correlation...

  19. Characteristics and properties of TiO2 thin film photocatalysts fabricated by sol-gel process

    International Nuclear Information System (INIS)

    Transparent TiO2 thin films have been prepared through a sol-gel process on the surface of glass pipes and characterized by XRD, Raman, UV-Vis and XPS in this paper. Results show that the absorption of the samples calcined at 773 K is obviously stronger than that calcined at 573 K between 290 and 330 nanometer. The films heated at 573 K are still in amorphous state but show good photocatalytic activities. With the increasing of heating temperature, the photocatalytic activities of TiO2 films decrease gradually. In addition, photocatalytic activity of TiO2 films increases gradually with the increment of coating cycles. (authors)

  20. Growth of TiO2 Thin Films with Anatase and Rutile Structures by Laser Ablation

    Science.gov (United States)

    Kennedy, R. J.; Stampe, P. A.

    2002-03-01

    Interest in the growth of TiO2 thin films has been rekindled due to the discovery of room temperature ferromagnetism in TiO_2:Co. Ferromagnetism has been reported in both the anatase and the rutile phases of this compound, resulting in some confusion as to the exact role played by the crystal structure. To resolve the structural dependence it would be beneficial to be able to grow films with both structures under identical growth conditions. We show that films of TiO2 can be grown by laser ablation on a variety of substrates with either anatase or rutile structure depending of the substrate lattice size and orientation. Although epitaxial crystal growth is obtained, more than one crystallite orientation is usually present for materials with poor substrate/film lattice match. We present detailed x-ray structure data on the growth orientation of films on different orientations of LaAlO_3, SrTiO_3, YSZ, Al_2O3 and Mica. We also present atomic force microscope images of the surfaces showing grain size and roughness dependence on substrate material. Supported by DARPA through ONR Grants MDA972-02-1-0002 and N-00014-99-1-1094

  1. Self-Cleaning Properties of Vanadium Doped TiO2 Sol-Gel Derived Thin Films

    Directory of Open Access Journals (Sweden)

    Mehrnoush Mokhtarimehr

    2013-07-01

    Full Text Available In this study, vanadium doped TiO2 thin films were deposited on glass substrates using a sol-gel dip-coating process. X-Ray diffraction (XRD, Fourier transform infrared spectroscopy (FTIR and UV-Vis spectrophotometer were used to characterize the structural, chemical and the optical properties of the thin films. The photo-catalytic activities of films were investigated by methylene blue degradation. Water contact angle on the film surfaces was measured by a water contact angle analyzer. The results indicated that vanadium doping had a significant effect on the self-cleaning properties of TiO2 thin films.

  2. Basella alba rubra spinach pigment-sensitized TiO2 thin film-based solar cells

    Science.gov (United States)

    Gokilamani, N.; Muthukumarasamy, N.; Thambidurai, M.; Ranjitha, A.; Velauthapillai, Dhayalan

    2015-03-01

    Nanocrystalline TiO2 thin films have been prepared by sol-gel dip coating method. The X-ray diffraction results showed that TiO2 thin films annealed at 400, 450 and 500 °C are of anatase phase and the peak corresponding to the (101) plane is present in all the samples. The grain size of TiO2 thin films was found to increase with increasing annealing temperature. The grain size is found to be 20, 25 and 33 nm for the films annealed at 400, 450 and 500 °C. The structure of the TiO2 nanocrystalline thin films have been examined by high-resolution transmission electron microscope, Raman spectroscopy and FTIR spectroscopy. TiO2 thin films were sensitized by natural dyes extracted from basella alba rubra spinach. It was found that the absorption peak of basella alba rubra extract is at about 665 nm. The dye-sensitized TiO2-based solar cell sensitized using basella alba rubra exhibited a J sc of 4.35 mA cm-2, V oc of 0.48 V, FF of 0.35 and efficiency of 0.70 %. Natural dyes as sensitizers for dye-sensitized solar cells are promising because of their environmental friendliness, low-cost production and fully biodegradable.

  3. A novel externally charged Fe-doped TiO2 thin film with extraordinary oxygen sensitivity

    International Nuclear Information System (INIS)

    Different configurations of Fe-doped TiO2 thin films deposited on both quartz glass and heavily doped p-type silicon substrates were prepared by the sol-gel method. Oxygen-sensing properties of the TiO2 thin films were measured through the variations in resistivity under a low operating temperature of 300 0C using a micro-current instrument. Extraordinary oxygen sensitivity up to about 200 times of resistance ratio appeared only in the configuration of TiO2 thin film deposited on the heavy doped p-type silicon substrate with Fe doping of 4-6 mol %, in which the rutile phase content was maximum. The high oxygen sensitivity was induced by the extrinsic positive charge gained and was controlled by both the rutile phase content in the thin film and the positive charge transmitted from the heavily doped p-type single crystal silicon to the thin film

  4. Structural, morphological, and optical properties of TiO2 thin films synthesized by the electro phoretic deposition technique

    OpenAIRE

    Ghrairi, Najla; Bouaicha, Mongi

    2012-01-01

    In this work, we report the structural, morphological, and optical properties of TiO2 thin films synthesized by the electro phoretic deposition technique. The TiO2 film was formed on a doped fluorine tin oxide (SnO2:F, i.e., FTO) layer and used as a photo electrode in a dye solar cell (DSC). Using spectroscopic ellipsometry measurements in the 200 to 800?nm wavelengths domain, we obtain a thickness of the TiO2 film in the range of 70 to 80?nm. Characterizations by X-ray diffraction and at...

  5. Optimization of experimental parameters in preparing multinanoporous TiO2 thin films by the anodic oxidation method

    Scientific Electronic Library Online (English)

    Gracien B., Ekoko; Joseph K-K., Lobo; Omer M., Mvele; Antoine K., Mbongo; Jérémie L., Muswema; Clarisse Z., Lefuni.

    2013-08-01

    Full Text Available The anodic oxidation method has been applied to the preparation of multinanoporous TiO2 thin films. The experimental parameters, including the electrolyte nature, oxidation voltage, and oxidation time have been carefully controlled. Their influence on the structure, morphology and photocatalytic act [...] ivity of the prepared TiO2 films has been evaluated by measuring the current density. The result showed that there was a relatively wide range of preparation conditions, and the internal relationship between the structure and the photocatalytic properties of the TiO2 films was analyzed.

  6. Thin TiO2 films deposited by implantation and sputtering in RF inductively coupled plasmas

    International Nuclear Information System (INIS)

    The achievement of titanium dioxide (TiO2) thin films in the rutile crystalline phase is reported. The samples result from the implantation of oxygen ions of Ti in argon/oxygen plasma generated by inductively coupled RF at a commercial 13.56 MHz frequency. Simultaneously, a sputtering process is conducted on the titanium target in order to produce TiO2 thin films in the anatase phase over silicon and glass substrates. Both implantation and sputtering processes shared the same 500 W plasma with the target, polarized between 0 and -3 kV. The substrates were placed between 2 and 3 cm from the target, this distance being found to be determinant of the TiO2 deposition rate. The rutile phase in the target was obtained at temperatures in the order of 680 degrees C and the anatase (unbiased) one at about 300 degrees C without any auxiliary heating. The crystalline phases were characterized by x ray diffraction and Raman spectroscopy. The morphology and average roughness were established by means of scanning electronic and atomic force microscopy, whereas the reaction products generated during the oxidation process were analyzed by mass spectrometry. Finally, the stoichiometric composition was measured by means of X-ray photoelectron spectroscopy.

  7. Tio2 Nanoparticles Coated With Porphyrin Dye Thin Film As Fluorescence Gas Sensor

    International Nuclear Information System (INIS)

    This research explores the possibility of using fluorescence technique to detect the presence of volatile organic compounds based on a single sensing material. The material used was TiO2 nanoparticles coated with porphyrin dye. The TiO2 nanoparticles colloid is in a sol-gel form synthesized from titanium (IV) ethoxide in ethanol with addition of potassium chloride (KCl) as stabilizer. TiO2 nanoparticles were then coated with porphyrin dye, Manganese (III) 5,10,15,20 tetra (4-pyridyl)-21H, 23H porphine chloride tetrakis (meta chloride). The coated nanoparticles were deposited on quartz substrate using self-assembly through dip coating technique. The sensing properties of the thin film toward volatile organic compounds; ethanol, acetone, cyclohexane and 2-propanol were studied using luminescence spectrometer. It was found that the thin film produced different emission spectra peaks for different volatile organic compounds (VOCs). Hence, it eases chemical identification process and potentially be use as fluorescence gas sensor. (author)

  8. Thin Functional Films of TiO2 Nanoparticles.

    Czech Academy of Sciences Publication Activity Database

    Morozová, Magdalena; Kluso?, Petr; Hejda, S.; Kment, Št?pán; Šolcová, Olga

    Praha : J.Heyrovský Institute of Physical Chemistry, v. v. i, 2011 - (Mansfeldová, V.; Tarábková, H.), s. 56 ISBN 978-80-87351-17-8. [Heyrovský Discussion - Nanostructures on Electrodes /44./. T?eš? (CZ), 26.06.2011-30.06.2011] R&D Projects: GA ?R GD203/08/H032; GA AV ?R KAN400720701 Institutional research plan: CEZ:AV0Z40720504; CEZ:AV0Z10100522 Keywords : spectroscopy * films * nanoparticles Subject RIV: CF - Physical ; Theoretical Chemistry

  9. Effects of Annealing on Microstructure and Optical Properties of TiO2 Sculptured Thin Films

    International Nuclear Information System (INIS)

    The evolution of microstructure and optical properties of TiO2 sculptured thin films under thermal annealing is reported. XRD, field emission SEM, UV-Vis-NIR spectra are employed to characterize the microstructural and optical properties. It is found that the optimum annealing temperature for linear birefringence is 500°C. The maximum of transmission difference for linear birefringence is up to 18%, which is more than twice of that in as-deposited thin films. In addition, the sample annealed at 500°C has a minimum of column angle about 12°C. The competitive process between the microstructural and optical properties is discussed in detail. Post-annealing is a useful method to improve the linear birefringence in sculptured thin films for practical applications. (condensed matter: structure, mechanical and thermal properties)

  10. Effect of Annealing on Structure, Morphology, Electrical and Optical Properties of Nanocrystalline TiO2 Thin Films

    Directory of Open Access Journals (Sweden)

    B.T. Raut

    2011-01-01

    Full Text Available Semi-transparent and highly conducting nanostructured titanium oxide thin films have been prepared by sol-gel method. Thin films of TiO2 deposited on glass substrates using spin coating technique and the effect of annealing temperature (400 - 700 °C on structural, microstructural, electrical and optical properties were studied. The X-ray diffraction and Atomic force microscopy measurements confirmed that the films grown by this technique have good crystalline tetragonal mixed anatase and rutile phase structure and homogeneous surface. The study also reveals that the rms value of thin film roughness increases from 7 to 19 nm. HRTEM image of TiO2 thin film (annealed at 700 °C shows that a grain of about 50 - 60 nm in size is really aggregate of many small crystallites of around 10 - 15 nm. Electron diffraction pattern shows that the TiO2 films exhibited tetragonal structure. The surface morphology (SEM of the TiO2 film showed that the nanoparticles are fine with an average grain size of about 50 - 60 nm. The optical band gap slightly decreases from 3.26 - 3.24 eV and the dc electrical conductivity was found in the range of 10-6 to 10-5(?·cm-1 when the annealing temperature is changed from 400 to 700 °C. It is observed that TiO2 thin film annealed at 700 °C after deposition provide a smooth and flat texture suited for optoelectronic applications.

  11. TiO2 thin film growth using the MOCVD method

    Directory of Open Access Journals (Sweden)

    Bernardi M.I.B.

    2001-01-01

    Full Text Available Titanium oxide (TiO2 thin films were obtained using the MOCVD method. In this report we discuss the properties of a film, produced using a ordinary deposition apparatus, as a function of the deposition time, with constant deposition temperature (90 °C, oxygen flow (7,0 L/min and substrate temperature (400 °C. The films were characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM, atomic force microscopy (AFM and visible and ultra-violet region spectroscopy (UV-Vis. The films deposited on Si (100 substrates showed the anatase polycrystalline phase, while the films grown on glass substrates showed no crystallinity. Film thickness increased with deposition time as expected, while the transmittance varied from 72 to 91% and the refractive index remained close to 2.6.

  12. TiO2 thin film growth using the MOCVD method

    Scientific Electronic Library Online (English)

    M.I.B., Bernardi; E.J.H., Lee; P.N., Lisboa-Filho; E.R., Leite; E., Longo; J.A, Varela.

    2001-07-01

    Full Text Available Titanium oxide (TiO2) thin films were obtained using the MOCVD method. In this report we discuss the properties of a film, produced using a ordinary deposition apparatus, as a function of the deposition time, with constant deposition temperature (90 °C), oxygen flow (7,0 L/min) and substrate tempera [...] ture (400 °C). The films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and visible and ultra-violet region spectroscopy (UV-Vis). The films deposited on Si (100) substrates showed the anatase polycrystalline phase, while the films grown on glass substrates showed no crystallinity. Film thickness increased with deposition time as expected, while the transmittance varied from 72 to 91% and the refractive index remained close to 2.6.

  13. Magnetoelectric properties of Mn-substituted BiFeO3 thin films with a TiO2 barrier

    Science.gov (United States)

    Gu, Jian-Jun; Zhao, Guo-Liang; Cheng, Fu-Wei; Han, Jin-Rong; Liu, Li-Hu; Sun, Hui-Yuan

    2011-12-01

    Multiferroic thin films with the general formula TiO2/BiFe1-xMnxO3 (x=0.00, 0.05, 0.10 and 0.15) (TiO2/BFMO) were synthesized on Au/Ti/SiO2/Si substrates using a chemical solution deposition (CSD) method assisted with magnetron sputtering. X-ray diffraction analysis shows the thin films contained perovskite structures with random orientations. Compared with BFMO films, the leakage current density of the TiO2/BFMO thin films was found to be lower by nearly two orders of magnitude, and the remnant polarizations were increased by nearly ten times. The enhanced ferroelectric properties may be attributed to the lower leakage current caused by the introduction of the TiO2 layer. The J-E characteristics indicated that the main conduction mechanism for the TiO2/BFMO thin film was trap-free Ohmic conduction over a wide range of electric fields (0-500 kV/cm). In addition, ferromagnetism was observed in the Mn doped BFO thin films at room temperature. The origin of ferromagnetism is related to the competition between distortion of structure and decrease of grain size and decreasing net magnetic moment in films due to Mn doping.

  14. Nano-morphology of lithiated thin film TiO2 anatase probed with in situ neutron reflectometry

    International Nuclear Information System (INIS)

    In situ neutron reflectometry reveals the intercalation scheme of lithiated thin film TiO2 anatase in terms of phase boundary movement. The Li-rich lithium titanate phase progressively moves inside the TiO2 anatase electrode as a front parallel to the interface. In contrast to previous suggestions for this system, the phase front moves back during lithium extraction exactly in the way it came in. The electrochemical side reactions result in a ?5.5 nm-thick film on top of the TiO2 electrode extending into the organic electrolyte which is believed to passivate the Li-intercalation

  15. Fabrication and evaluation of TiO2/graphite silica bilayer thin films prepared by laser ablation method

    International Nuclear Information System (INIS)

    The bilayer thin film composed of graphite silica (GS) and TiO2 was prepared by the laser ablation technique. The properties of the thin films considerably depended on the laser ablation conditions such as gas pressure and substrate temperature in a chamber. The laser ablation of GS caused complete disappearance of the quartz XRD (X-ray diffraction) peaks in GS. The GS loading, especially at a thickness of around 200 nm, led to significant enhancement in the photocatalytic activity of the TiO2 thin film for the hydrogen production and the methylene blue decomposition in spite of the destruction of the quartz crystal in GS

  16. Photocatalytic decomposition of diclofenac potassium using silver-modified TiO2 thin films

    International Nuclear Information System (INIS)

    The effects of silver insertion on the TiO2 photocatalytic activity for the degradation of diclofenac potassium were reported here. Techniques such as X-ray diffraction, scanning electron microscopy and UV-Vis spectroscopy were used to comprehend the relation between structure and properties of the silver-modified TiO2 thin films obtained by the sol-gel method. The lattice parameters and the crystallinity of TiO2 anatase phase were affected by inserted silver, and the film thickness increased about 4 nm for each 1 wt.% of silver inserted. The degradation of diclofenac potassium and by-products reached an efficiency of 4.6 mgC W-1 when the material was modified with silver. Although the first step of degradation involves only the photochemical process related to the loss of the chlorine and hydrogen atoms. This cyclization reaction leads to the formation of intermediate, which degradation is facilitated by the modified material

  17. Photocatalytic antibacterial performance of Sn4+-doped TiO2 thin films on glass substrate

    International Nuclear Information System (INIS)

    Pure anatase, nanosized and Sn4+ ion doped titanium dioxide (TiO2) particulates (TiO2-Sn4+) were synthesized by hydrothermal process. TiO2-Sn4+ was used to coat glass surfaces to investigate the photocatalytic antibacterial effect of Sn4+ doping to TiO2 against gram negative Escherichia coli (E. coli) and gram positive Staphylococcus aureus (S. aureus). Relationship between solid ratio of TiO2-Sn4+ in coatings and antibacterial activity was reported. The particulates and the films were characterized using particle size analyzer, zeta potential analyzer, Brunauer-Emmett-Teller (BET), X-ray diffractometer (XRD), SEM, AAS and UV/VIS/NIR techniques. The results showed that TiO2-Sn4+ is fully anatase crystalline form and easily dispersed in water. Increasing the solid ratio of TiO2-Sn4+ from 10 to 50% in the coating solution increased antibacterial effect

  18. Preparation and Characterization of TiO2-SiO2 Thin Films

    International Nuclear Information System (INIS)

    Sol-gel, is a method being used for preperation of thin films for a very long time. Its easy application process with easily available equipments that are used and the low process temperatures are the reasons for being utilized this much. A very common thin film type, TiO2-SiO2, that has been used in optical applications for a long time, is the basic structure involved in this research. In this work, the titania (TiO2) and the silica (SiO2) solutions which had been preperated seperately, were mixed with different ratios, and the differences between these mixtures that might had been occurred were investigated. The glass substrates, which had been cleaned with a special method were dipped into the mixed solutions with a constant speed which they had exactly the same while they were being withdrawned. After being dried in mid-air for a while, they were heated to 150 degree and then were dipped again. Once the number of the layers that was required is reached with reprocesses, the substrates were heated to 600 degree. The optical and the structural properties of the films deposited on the substrates were investigated. Some differences in optical properties of these films that were produced from different ratios of solutions were observed as result

  19. Influence of Nb dopant on the structural and optical properties of nanocrystalline TiO2 thin films

    International Nuclear Information System (INIS)

    Highlights: ? We coated Nb-doped TiO2 films on glazed porcelain via sol–gel dip coating method. ? We examined coatings by degradation of MB solution and optical light transmittance. ? Coatings show enhanced photo-catalytic activity in 1 mol% Nb. ? Nb doping inhibited the grain growth, and which are found to inhibit the anatase to rutile phase transformation. - Abstract: In this study, preparation of Nb-doped (0–20 mol% Nb) TiO2 dip-coated thin films on glazed porcelain substrates via sol–gel process has been investigated. The effects of Nb on the structural, optical, and photo-catalytic properties of applied thin films have been studied by X-ray diffraction, Raman spectroscopy, and scanning electron microscopy. Surface topography and surface chemical state of thin films was examined by atomic force microscope and X-ray photoelectron spectroscopy. XRD and Raman study showed that the Nb doping inhibited the grain growth. The photo-catalytic activity of the film was tested on degradation of methylene blue. Best photo-catalytic activity of Nb-doped TiO2 thin films were measured in the TiO2–1 mol% Nb sample. The average optical transmittance of about 47% in the visible range and the band gap of films became wider with increasing Nb doping concentration. The Nb5+ dopant presented substitutional Ti4+ into TiO2 lattice.

  20. Transport properties of (Sn, Ti)O2 polycrystalline ceramics and thin films

    International Nuclear Information System (INIS)

    Polycrystalline ceramics of (Sn,Ti)O2 were prepared by the impregnation of TiO2 with SnCl4 in the presence of NH3 aq. Rf reactive sputtering from Ti-Sn metallic target was used to deposit thin films. The re-equilibration kinetics were monitored by measuring dc electrical conductivity as a function of temperature, 850 K 15 Pa 2) -5 Pa. The chemical diffusion coefficient was found to be independent of p(O2). A constant value of the activation energy of 0.7-0.8 eV was derived from the temperature dependence of the chemical diffusion coefficient. (author)

  1. Ellipsometric study of Atomic Layer Deposited TiO2 thin films

    Science.gov (United States)

    Jaiswal, Piyush; Kunte, G. V.; Umarji, A. M.; Shivashankar, S. A.

    2009-06-01

    Atomic layer deposition was used to obtain TiO2 thin films on Si (100) and fused quartz, using a novel metal organic precursor. The films were grown at 400° C, varying the amount of oxygen used as the reactive gas. X-ray diffraction showed the films to be crystalline, with a mixture of anatase and rutile phases. To investigate their optical properties, ellipsometric measurements were made in the UV-Vis-NIR range (300-1700 nm). Spectral distribution of various optical constants like refractive index (n), absorption index (k), transmittance (T), reflectance (R), absorption (A) were calculated by employing Bruggemann's effective medium approximation (BEMA) and Maxwell-Garnet effective medium approximation, in conjunction with the Cauchy and Forouhi-Bloomer (FB) dispersion relations. A layered optical model has been proposed which gives the thickness, elemental and molecular composition, amorphicity and roughness (morphology) of the TiO2 film surface and and the film/substrate interface, as a function of oxygen flow rate The spectral distribution of the optical band gap (Egopt), complex dielectric constants (?'and?"), and optical conductivity (?opt), has also been determined.

  2. Photocatalytic Separate Evolution of Hydrogen and Oxygen over Highly Ordered Nanorods and Bulk TiO2 Thin Films

    Directory of Open Access Journals (Sweden)

    Chao-Wei Huang

    2013-01-01

    Full Text Available Three types of photocatalytic TiO2 thin films with different structures, nanorods (NR-TiO2, mesoporous (MP-TiO2, and bulk structure (BK-TiO2, were prepared by evaporation induced self-assembling process or electron beam induced deposition method. The post-calcination treatment at 400oC was performed for all TiO2 thin films to induce their crystallinity. The TiO2 structure on the film properties were studied by material characterizations. The photoelectrochemical characteristics of the TiO2 films were investigated using a potentiostat. Under UV-light irradiation, a highest net photocurrent of 0.747 mA was observed for the NR-TiO2 thin film. To demonstrate the photoactivity of the prepared TiO2 thin films, water-splitting reactions were conducted. The yields of hydrogen and oxygen were 35.8 and 17.2 ?mole, respectively after 8 hr. of UV-light irradiation on NR-TiO2.

  3. Dry Etching Properties of TiO2 Thin Film Using Inductively Coupled Plasma for Resistive Random Access Memory Application

    Directory of Open Access Journals (Sweden)

    Young-Hee Joo

    2012-06-01

    Full Text Available In this work, we investigated to the etching characteristics of TiO2 thin film and the selectivity using the inductivelycoupled plasma system. The etch rate and the selectivity were obtained with various gas mixing ratios. The maximumetch rate of TiO2 thin film was 61.6 nm/min. The selectivity of TiO2 to TiN, and TiO2 to SiO2 were obtained as 2.13 and1.39, respectively. The etching process conditions are 400 W for RF power, -150 V for DC-bias voltage, 2 Pa for theprocess pressure, and 40? for substrate temperature. The chemical states of the etched surfaces were investigatedwith X-ray photoelectron spectroscopy (XPS. Its analysis showed that the etching mechanism was based on thephysical and chemical pathways in the ion-assisted physical reaction.

  4. Electrochromic TiO2, ZrO2 and TiO2-ZrO2 thin films by dip-coating method

    OpenAIRE

    Ivanova, T.; Harizanova, A.; Koutzarova, T.; Krins, Natacha; Vertruyen, Be?ne?dicte

    2009-01-01

    Sol-gel processing of TiO2, ZrO2 and mixed Ti/Zr oxide thin films has been studied as application of these coatings in electrochromic devices. Their structural transformations as a function of annealing temperatures were analyzed by XRD and FTIR techniques. Electrochromic behavior of the three kind materials was investigated by cyclic voltammetry and the basic electrochromic characteristics were determined. (c) 2009 Elsevier B.V. All rights reserved.

  5. Electrochromic TiO2, ZrO2 and TiO2-ZrO2 thin films by dip-coating method

    International Nuclear Information System (INIS)

    Sol-gel processing of TiO2, ZrO2 and mixed Ti/Zr oxide thin films has been studied as application of these coatings in electrochromic devices. Their structural transformations as a function of annealing temperatures were analyzed by XRD and FTIR techniques. Electrochromic behavior of the three kind materials was investigated by cyclic voltammetry and the basic electrochromic characteristics were determined.

  6. Metal-to-Insulator Transition in Anatase TiO2 Thin Films Induced by Growth Rate Modulation

    International Nuclear Information System (INIS)

    We demonstrate control of the carrier density of single phase anatase TiO2 thin films by nearly two orders of magnitude by modulating the growth kinetics during pulsed laser deposition, under fixed thermodynamic conditions. The resistivity and the intensity of the photoluminescence spectra of these TiO2 samples, both of which correlate with the number of oxygen vacancies, are shown to depend strongly on the growth rate. A quantitative model is used to explain the carrier density changes.

  7. An investigation of super-hydrophilic properties of TiO2/SnO2 nano composite thin films

    International Nuclear Information System (INIS)

    A sol–gel dip coating technique was used to fabricate TiO2/SnO2 nano composite thin films on soda-lime glass. The solutions of SnO2 and TiO2 were mixed with different molar ratios of SnO2:TiO2 as 0, 3, 4, 6, 8, 9, 10.5, 13, 15, 19.5, 25 and 28 mol.% then the films were prepared by dip coating of the glasses. The effects of SnO2 concentration, number of coating cycles and annealing temperature on the hydrophilicity of films were studied using contact angle measurement. The films were characterized by means of scanning electron microscopy, X-ray diffraction and atomic force microscopy measurements. The nano composite thin films fabricated with 8 mol.% of SnO2, four dip coating cycles and annealing temperature of 500 °C showed super-hydrophilicity.

  8. Synthesis and characterization of TiO2 thin films doped with copper to be used in photocatalysis / Síntesis y caracterización de películas delgadas de TiO2 dopadas con cobre para ser usadas en fotocatálisis

    Scientific Electronic Library Online (English)

    Carlos Enrique, Díaz-Uribe; William Andrés, Vallejo Lozada; Fernando, Martínez Ortega.

    2013-06-01

    Full Text Available In this work we studied the influence of incorporation of copper into TiO2 thin films on structural, optical and surface properties of TiO2 thin films. The as-grown TiO2 was synthesized by sol gel method using titanium isopropoxide, and the TiO2 thin films were deposited by spin coating method. TiO2 [...] copper-doped (Cu:TiO2) was synthesized by impregnation method using Cu(NO3).H2O as source of Cu(II), the Cu:TiO2 thin films were deposited by spin coating method. The properties of the compounds obtained were evaluated by measurements of X-ray diffraction (XRD) and diffuse reflectance. The XRD results showed that Cu doping change the crystalline phase radio of the films, XRD pattern of TiO2 indicated that films grow with anatase structute, while Cu:TiO2 thin films presented a polycrystalline mixture of anatase/rutile. Reflectance analysis indicated that TiO2 presents an energy band gap of 3.25 eV and the Cu:TiO2 presents a shift-red of the band gap to 2,9 eV. The results suggest that doping with copper improved the harvesting of the TiO2 to visible radiation.

  9. Influence of substrate and annealing temperatures on optical properties of RF-sputtered TiO 2 thin films

    Science.gov (United States)

    Hasan, M. M.; Haseeb, A. S. M. A.; Saidur, R.; Masjuki, H. H.; Hamdi, M.

    2010-04-01

    TiO 2 thin films were deposited on unheated and heated glass substrates at an elevated sputtering pressure of 3 Pa by radio frequency (RF) reactive magnetron sputtering. TiO 2 films deposited at room temperature were annealed in air for 1 h at various temperatures ranging from 300 to 600 °C. The structural and optical properties of the thin films were investigated using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and ultraviolet-visible-near infrared (UV-VIS-NIR) spectrophotometry. XRD results show that as-grown and post-annealed TiO 2 films have anatase crystal structure. Higher substrate and annealing temperatures result in a slight increase of crystallinity. TiO 2 films deposited at different substrate temperatures exhibit high visible transmittance and the transmittance decreases slightly with an increase in annealing temperature. The refractive indices (at ? = 550 nm) of the as-deposited and annealed films are found to be in the range of 2.31-2.37 and 2.31-2.35, respectively. Extinction coefficient decreases slightly with increasing substrate and annealing temperatures. The indirect and direct optical band gap of the as-grown films increases from 3.39 to 3.42 eV and 3.68 to 3.70 eV, respectively, with the increase of substrate temperatures. Annealed TiO 2 films also exhibit an increase in the values of indirect and direct optical band gap.

  10. Photo-induced hydrophilicity of TiO2-xNx thin films on PET plates

    International Nuclear Information System (INIS)

    TiO2-xNx thin films were deposited on PET (polyethylene terephthalate) plates by sputtering a TiN target in a N2/O2 plasma and without heating. X-ray photoemission spectroscopy (XPS) was used to investigate the N 1s, Ti 2p core levels and the nitrogen composition in the TiO2-xNx films. The results indicate that Ti-O-N bonds are formed in the thin films. Two nitrogen states, substitution and interstitial nitrogen atoms, were attributed to peaks at 396 and 399 eV, respectively. It was observed that the nitrogen atoms occupy both the substitutive and interstitial sites in respective of the nitrogen content in the thin films. UV-VIS absorption spectroscopy of PET coated thin films shows a significant shift of the absorption edge to lower energy in the visible-light region. UV and visible-light irradiation are used to activate PET coated thin films for the development of hydrophilicity. The photo-induced surface wettability conversion reaction of the thin films has been investigated by means of water contact angle measurement. PET plates coated with TiO2-xNx thin films are found to exhibit lower water contact angle than non-coated plates when the surface is illuminated with UV and visible light. The effects of nitrogen doping on photo-generated hydrophilicity of the thin films are investigated in this work

  11. Sol-Gel TiO2 thin films sensitized with the mulberry pigment cyanidin

    OpenAIRE

    Emerson Henrique de Faria; Alex Lemes Marçal; Eduardo José Nassar; Katia Jorge Ciuffi; Paulo Sergio Calefi

    2007-01-01

    TiO2 films have various applications, among them solar cells and photodegradation of pollutants. In this study, we investigated TiO2 films functionalized with the organic dye cyanidin extracted from black mulberry (Morus nigra). The TiO2 was functionalized by the sol-gel method and the film was deposited on glass substrates by dip-coating. Our aim was to investigate the interaction between the semiconductor and the dye, as well as the influence of the velocity and number of deposits on the ch...

  12. Titanium dioxide (TIO2) thin film and plasma properties in RF magnetron sputtering

    International Nuclear Information System (INIS)

    Lately, titanium dioxide (TiO2) films with anatase crystalline property received numerous attentions as unique material properties. There are wide applications of TiO2 thin film such as for photocatalytic application in solar cell. In the present study, radio frequency (RF) magnetron sputtering technique has been used to produce high dense, homogeneously controllable film layer at low deposition temperature using titanium (Ti) target. The diameter of the Ti target is 3 inch with fixed discharge power of 400W. Magnetron sputtering plasma has been produced in high purity 99.99% Argon (Ar) and 99.99% Oxygen (O2) environment pressure ranging from 5 to 20 mTorr. The TiO2 were growth on silicon and glass substrates. Substrate temperature during deposition was kept constant at 400°C. The distance between target and substrate holder was maintain at 14 cm with rotation of 10 rotation-per-minutes. Our X-ray diffraction result, shows anatase crystalline successfully formed with characterization peaks of plane (101) at 2? = 25.28°, plane (202) at 2? = 48.05° and plane (211) at 2? = 55.06°. In addition, it is our interest to study the plasma properties and optical spectrum of Ti, Ti+ , O- , ArM and Ar+ in the chamber during the deposition process. Result of emission line intensities, electron density and temperature from optical spectroscope and Langmuir probe will be discuss further during the workshop. This works were supported by Graduateis works were supported by Graduate Incentive Scheme of Universiti Tun Hussein Onn Malaysia (UTHM) and Fundamental Research Grant Scheme of Ministry of Higher Education, Malaysia. (author)

  13. Power-law photoconductivity time decay in nanocrystalline TiO2 thin films

    International Nuclear Information System (INIS)

    The sub-band-gap excited photoconductivity (PC) time decay and the film structure of rf-sputter deposited nanocrystalline TiO2 thin films have been studied. Atomic force microscopy and x-ray diffraction measurements were used to assess roughness, crystalline structure and mean grain size of the films. Samples fabricated under different deposition conditions exhibit different microstructures and absolute PC, but similar persistent PC behaviour after switching off the light source. The very slow PC decay can be well represented by a function that is nearly constant for short times and decreases as a power law for times longer than about 100 s. This function is shown to be consistent with a rate equation characterized by a relaxation time that increases linearly with time. This behaviour, in turn, agrees with predictions of a previously reported model that assumes electron-hole recombination limited by carrier-density-dependent potential barriers associated with inhomogeneities. These results may have important implications on attempts to determine distributions of trap energies from PC decay curves in TiO2

  14. Structural characterisation of sprayed TiO2 films for extremely thin absorber layer solar cells

    International Nuclear Information System (INIS)

    We have examined in detail the structural features of TiO2 films fabricated by spray pyrolysis. The spray solution was produced from the dissolution of Ti powder in a hydrogen peroxide and ammonium hydroxide solution. The resulting peroxo-polytitanic acid solution was diluted in water and sprayed onto heated substrates through an air-atomizing nozzle. Each sample was characterised principally by X-ray powder diffraction and scanning electron microscopy. The effect of spray solution composition and rate has been studied and a brief comparison to films produced by an alternative route ('doctor blade') provided. The films were shown to consist of almost single phase anatase and to be porous. It has been demonstrated that the growth process was uniform although the degree of preferred orientation could be controlled through the concentration of the spray solution. The lattice parameters are both shown to increase slightly with concentration and volume of solution deposited. Semi-quantitative microstructural analyses showed that the crystallites formed are consistently larger than those formed by the doctor blade process although they contain significantly more microstrain. Further, it is demonstrated that thin window layers of copper indium disulfide, also formed by spray pyrolysis, have a conformal relationship with the TiO2

  15. Characterization of TiO2/Polyelectrolyte Thin Film Fabricated by a Layer-by-Layer Self-Assembly Method

    Science.gov (United States)

    Kim, Jin-Ho; Shiratori, Seimei

    2005-10-01

    Multilayers thin films consisted of TiO2 nanoparticles and oppositely charged polyelectrolytes were fabricated by layer-by-layer self-assembly method and their properties were characterized. At pH 2.0, TiO2 nanoparticles were maximally deposited with poly(sodium 4-styrenesulfonate) (PSS) and the thickness and the surface roughness of film assembled with poly(acrylic acid) (PAA) were largest because of the loopy structure of PAA in acidic solution. On the other hand, the thin film prepared with poly(vinylsulfonic acid-sodium salt) (PVS) showed the high deposition of TiO2, lowest surface roughness, high refractive index (n=2.1) at 632 nm, and high transmittance in visible range. In addition, this film composed of anatase nanoparticles showed good photocatalytic property by decomposing methyl orange molecules with UV irradiation.

  16. Thin films of photocatalytic TiO2 and ZnO deposited inside a tubing by spray pyrolysis

    International Nuclear Information System (INIS)

    Thin films of photocatalytic TiO2 and ZnO were deposited in Vycor tubing by a simple and reproducible spray pyrolysis technique. Films were transparent and non-light scattering. Film characterization by transmission electron microscopy shows that titanium oxide films were polycrystalline and that their structure corresponded to the tetragonal anatase phase. In addition, ZnO films were polycrystalline with a structure that belonged to the hexagonal Wurtzite type. The solar photocatalytic efficiency for butane degradation was compared to that of Degussa P-25 TiO2 powder (P-25). Reaction rate and reaction order were obtained from butane concentration measurements using the tubing as a non-circulating reactor exposed to solar radiation. The best fitting was obtained for a pseudo-first order rate constant. The TiO2-covered tubing shows very high photocatalytic activity, even higher than that of P-25, if activity per unit of catalyst mass is considered

  17. Nanostructured TiO2/carbon nanosheet hybrid electrode for high-rate thin-film lithium-ion batteries

    Science.gov (United States)

    Moitzheim, S.; Nimisha, C. S.; Deng, Shaoren; Cott, Daire J.; Detavernier, C.; Vereecken, P. M.

    2014-12-01

    Heterogeneous nanostructured electrodes using carbon nanosheets (CNS) and TiO2 exhibit high electronic and ionic conductivity. In order to realize the chip level power sources, it is necessary to employ microelectronic compatible techniques for the fabrication and characterization of TiO2-CNS thin-film electrodes. To achieve this, vertically standing CNS grown through a catalytic free approach on a TiN/SiO2/Si substrate by plasma enhanced chemical vapour deposition (PECVD) was used. The substrate-attached CNS is responsible for the sufficient electronic conduction and increased surface-to-volume ratio due to its unique morphology. Atomic layer deposition (ALD) of nanostructured amorphous TiO2 on CNS provides enhanced Li storage capacity, high rate performance and stable cycling. The amount of deposited TiO2 masks the underlying CNS, thereby controlling the accessibility of CNS, which gets reflected in the total electrochemical performance, as revealed by the cyclic voltammetry and charge/discharge measurements. TiO2 thin-films deposited with 300, 400 and 500 ALD cycles on CNS have been studied to understand the kinetics of Li insertion/extraction. A large potential window of operation (3-0.01 V); the excellent cyclic stability, with a capacity retention of 98% of the initial value; and the remarkable rate capability (up to 100 C) are the highlights of TiO2/CNS thin-film anode structures. CNS with an optimum amount of TiO2 coating is proposed as a promising approach for the fabrication of electrodes for chip compatible thin-film Li-ion batteries.

  18. Thin Tin and Tio2 Film Deposition in Glass Samples by Cathodic Cage

    Scientific Electronic Library Online (English)

    Rômulo Ribeiro Magalhães de, Sousa; Francisco Odolberto de, Araújo; Thercio Henrique de Carvalho, Costa; Igor Oliveira, Nascimento; Francisco Eroni Paes, Santos; Clodomiro, Alves Júnior; Michelle Cequeira, Feitor.

    2015-04-01

    Full Text Available Thin nitride and titanium dioxide films were produced using an innovative technique called cathodic cage depositon. Uniformity, three-dimensionality and high rate deposition are some of the advantages of this technique. In this study we discuss the influences of temperature, treatment time and gaseo [...] us atmosphere on the characteristics of the deposited films. The TiN (titanium nitride) and TiO2 (titanium dioxide) films were produced using a high deposition rate of 2,5 µm/h at a work temperature and pressure of 400°C and 150 Pa respectively. EDS technique was used to identify the chemical composition of the thin film deposited, whilst Raman spectroscopy indicated the phases present confirmed by DRX analysis. The thickness of the deposited films was studied using electron microscopy scanning. The results based on the deposition parameters confirm the great efficiency and versatility of this technique, which allows a uniform three-dimensional film deposition on any material without the appearance of stress. Compared to other techniques, cathodic cage deposition enables deposition at lower temperatures and higher pressures.

  19. Room temperature ferromagnetism in Mn doped TiO2 thin films: Electronic structure and Raman investigations

    Science.gov (United States)

    Sharma, Sudesh; Chaudhary, Sujeet; Kashyap, Subhash C.; Sharma, Shiv K.

    2011-04-01

    In this work dc-magnetization, electronic structural, and Raman investigations of Ti1-xMnxO2 (x = 0.00, 0.05, 0.10, and 0.15) thin films deposited on fused-quartz substrate by a simple and cost effective spray pyrolysis technique have been reported. X-ray diffraction revealed the formation of pure anatase TiO2 phase devoid of elemental Mn clusters in all the Mn incorporated TiO2 films. It is established by x-ray photoelectron spectroscopic (XPS) measurements that Ti ions substituted by Mn ions in both divalent and trivalent states in the TiO2 matrix. No peak corresponding to Mn+4 could be evidenced by XPS. The Raman study has further established the formation of TiO2 in anatase structure in both pure TiO2 and Mn-doped TiO2 films. The Ti1-xMnxO2 films with x ? 0.05 exhibit ferromagnetic ordering at room temperature which arises most likely due to formation of bound magnetic polarons.

  20. Contact Angle of TiO2/SnO2 Thin Films Coated on Glass Substrate

    Directory of Open Access Journals (Sweden)

    Weerachai SANGCHAY

    2014-05-01

    Full Text Available The self-cleaning effect in terms of contact angle value and photocatalytic activity of TiO2 and TiO2/SnO2 thin films coated on glass substrate was measured. The thin films were prepared using a sol-gel dip coating technique and calcinated at a temperature of 500 °C for 2 h with a heating rate of 10 °C/min. The microstructures of the fabricated thin films were characterized by SEM and XRD techniques. The photocatalytic properties of the thin films were also tested via the degradation of methylene blue (MB solution under UV irradiation. Finally, the self-cleaning properties of the thin films were evaluated by measuring the contact angle of water droplets on the thin films with and without UV irradiation. It was found that 1 %mol SnO2/TiO2 thin films showed the highest of photocatalytic activity and provided the most self-cleaning properties.doi:10.14456/WJST.2014.21

  1. Waveguiding Properties of Nano-Structured TiO2 Thin Films Synthesized by Sol-Gel Process

    Science.gov (United States)

    Znaidi, L.; Touam, T.; Vrel, D.; Kunetsova, I. N.; Fischer, A.; Boudrioua, A.

    2011-12-01

    TiO2 thin films were synthesized by sol-gel process: titanium tetraisopropoxide (TTIP) was dissolved in isopropanol, and then hydrolyzed by adding a water/isopropanol mixture with a controlled hydrolysis ratio. The as prepared sol was deposited by `dip-coating' on a glass substrate with a controlled withdrawal speed. The obtained films were annealed at 350 and 500 °C (2 h). The structural, morphological and optical properties of the prepared films were analyzed by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM). The optical and waveguiding properties of TiO2 films were investigated for both annealing temperatures using m-lines spectroscopy. The results show that our fabricated TiO2 waveguides are multimodes and demonstrate low propagation losses of 0.9 dB?cm-1.

  2. A new room temperature gas sensor based on pigment-sensitized TiO2 thin film for amines determination.

    Science.gov (United States)

    Yanxiao, Li; Xiao-bo, Zou; Xiao-wei, Huang; Ji-yong, Shi; Jie-wen, Zhao; Holmes, Mel; Hao, Limin

    2015-05-15

    A new room temperature gas sensor was fabricated with pigment-sensitized TiO2 thin film as the sensing layer. Four natural pigments were extracted from spinach (Spinacia oleracea), red radish (Raphanus sativus L), winter jasmine (Jasminum nudiflorum), and black rice (Oryza sativa L. indica) by ethanol. Natural pigment-sensitized TiO2 sensor was prepared by immersing porous TiO2 films in an ethanol solution containing a natural pigment for 24h. The hybrid organic-inorganic formed films here were firstly exposed to atmospheres containing methylamine vapours with concentrations over the range 2-10 ppm at room temperature. The films sensitized by the pigments from black-rice showed an excellent gas-sensitivity to methylamine among the four natural pigments sensitized films due to the anthocyanins. The relative change resistance, S, of the films increased almost linearly with increasing concentrations of methylamine (r=0.931). At last, the black rice pigment sensitized TiO2 thin film was used to determine the biogenic amines generated by pork during storage. The developed films had good sensitivity to analogous gases such as putrscine, and cadaverine that will increase during storage. PMID:24934102

  3. Solvent-controlled preparation and photocatalytic properties of nanostructured TiO2 thin films with different morphologies

    International Nuclear Information System (INIS)

    Graphical abstract: Low-temperature growth of nanostructured TiO2 thin films was presented by a solvent-controlled method. Nanoparticle structured films in anatase phase have been successfully fabricated with some adjustment. The effects of the solvent were investigated and the formation mechanism was proposed. - Highlights: • Nanostructured TiO2 thin films with different morphologies were obtained at low temperature. • The effects of the solvent on the morphologies of the products were investigated. • The effects of the solvent on the phtocatalytic activity were investigated. - Abstract: A low-temperature growth method of nanostructured TiO2 thin films with different morphologies was reported. Rod-like, grass-like and nanosheet structured films have been successfully fabricated just by adjusting the ratio of different solvents. The effects of the solvent on the morphologies of the TiO2 nanostructures were investigated. The formation mechanism of different morphologies was proposed based on the experiment results. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM). The photocatalytic activity of as-prepared samples for the degradation of methylene blue (MB) in water was evaluated under UV illumination. Results showed that the solvents exhibited important effect on the morphologies and photocatalytic activity of as-prepared nanostructured titania films

  4. The properties of metal contacts on TiO2 thin films produced by reactive magnetron sputtering

    Directory of Open Access Journals (Sweden)

    Brus V. V.

    2010-10-01

    Full Text Available The article deals with research on volt-ampere characteristics of metal contacts (Al, Cr, In, Mo, Ti on titanium dioxide thin films and influence of annealing in vacuum on their electric properties. Volt-ampere characteristics measurements were taken by three-probe method. There was established that indium contact on TiO2 thin films possessed sharply defined ohmic properties.

  5. The oxidation stability of boron nitride thin films on MgO and TiO2 substrates

    International Nuclear Information System (INIS)

    The stability of BN thin film coatings (2--5 nm thick) on MgO and TiO2 substrates was investigated using transmission electron microscopy (TEM). The samples were heated in air for at least 16 hours at temperatures ranging from 773 K--1,273 K. On MgO supports, the BN thin film coating was lost by 1,073 K due to a solid state reaction with the substrate leading to formation of Mg2B2O5. No such reaction occurred with the TiO2 substrate and the BN was stable even at 1,273 K. However, the coating appeared to ball up and phase segregate into islands of near-graphitic BN and clumps of TiO2 (rutile). The oxidizing treatment appears to promote the transformation from turbostratic BN to graphitic BN

  6. Sol-Gel TiO2 thin films sensitized with the mulberry pigment cyanidin

    Directory of Open Access Journals (Sweden)

    Emerson Henrique de Faria

    2007-12-01

    Full Text Available TiO2 films have various applications, among them solar cells and photodegradation of pollutants. In this study, we investigated TiO2 films functionalized with the organic dye cyanidin extracted from black mulberry (Morus nigra. The TiO2 was functionalized by the sol-gel method and the film was deposited on glass substrates by dip-coating. Our aim was to investigate the interaction between the semiconductor and the dye, as well as the influence of the velocity and number of deposits on the characteristics of the film. Using ultraviolet-visible spectroscopy, we observed a shift from the maximum absorption band at 545 nm for the dye’s ethanol solution to 595 nm for the film, indicating interaction of the cyanidin with the TiO2. The absorption spectra in the infrared region of the functionalized TiO2 particles showed bands characteristic of the oxide and indicated their interaction with the dye. Using profilometry and m-line techniques, we found that the films presented thicknesses in the order of 100 nm. A SEM analysis confirmed the high density of the films.

  7. Sol-Gel TiO2 thin films sensitized with the mulberry pigment cyanidin

    Scientific Electronic Library Online (English)

    Emerson Henrique de, Faria; Alex Lemes, Marçal; Eduardo José, Nassar; Katia Jorge, Ciuffi; Paulo Sergio, Calefi.

    2007-12-01

    Full Text Available TiO2 films have various applications, among them solar cells and photodegradation of pollutants. In this study, we investigated TiO2 films functionalized with the organic dye cyanidin extracted from black mulberry (Morus nigra). The TiO2 was functionalized by the sol-gel method and the film was depo [...] sited on glass substrates by dip-coating. Our aim was to investigate the interaction between the semiconductor and the dye, as well as the influence of the velocity and number of deposits on the characteristics of the film. Using ultraviolet-visible spectroscopy, we observed a shift from the maximum absorption band at 545 nm for the dye’s ethanol solution to 595 nm for the film, indicating interaction of the cyanidin with the TiO2. The absorption spectra in the infrared region of the functionalized TiO2 particles showed bands characteristic of the oxide and indicated their interaction with the dye. Using profilometry and m-line techniques, we found that the films presented thicknesses in the order of 100 nm. A SEM analysis confirmed the high density of the films.

  8. Structural and Electrical Properties of TiO2 Thin Film Derived from Sol-gel Method using Titanium (IV Butoxide

    Directory of Open Access Journals (Sweden)

    Isrihetty Senain

    2010-12-01

    Full Text Available Fabrication of titanium dioxide (TiO2 thin film on microscope glass using sol-gel method has been studied intensively. The starting materials were titanium (IV butoxide, ethanol, acetic acid, triton x-100, hydrochloric acid and deionized water. The materials were mixed together to form the sols. Then, the heat and ageing treatment was applied to form stable sols. The sols were then spin coated on the glass substrate to form the homogenous and transparent TiO2 thin film. The TiO2 thin film was coated at several layers using specific conditions. To evaluate the performance of thin film, the crystallinity of the thin film was determined by using the x-ray diffractometer  (XRD. The change on the surface morphology was observed using atomic force microscope (AFM. The electrical property of the thin film was determined by doing the current-voltage (I-V analysis on the thin film. It has been successfully shown that the anatase crystalline phase was observed when the TiO2 thin film was heated at 500°C. The roughness and the crystalline phase of TiO2 thin film changed drastically with the growth conditions. Finally, the effect of film preparation to the film resistivity also showed a critical aspect where we should take into account during the preparation of TiO2 thin film.

  9. Photoactive and self-cleaning TiO2–SiO2 thin films on 316L stainless steel

    International Nuclear Information System (INIS)

    In this study, TiO2–SiO2 nanocomposite films with different amounts of SiO2 were prepared by sol–gel process and were coated onto stainless steel 316L. The effect of addition of various amount of SiO2 in the precursor solution on the photocatalysis, photo-generated hydrophilicity and self-cleaning property of TiO2 thin films was investigated by X-ray diffraction, Fourier transform infrared spectroscopy, water contact angle measurements and UV spectroscopy. In the tested ranges of SiO2 content and sintering temperature, the highest photocatalytic activity and self-cleaning property were observed in the 15 mol% SiO2 sample sintered at 750 °C. Addition of less than 30 mol% SiO2 had a suppressive effect on the transformation of anatase to rutile and on the crystal growth of anatase in the sintering heat treatment. Phase separation occurred in the composite films for SiO2 content of 30 mol% or more. - Highlights: ? We study the effect of SiO2 addition on the photocatalysis of TiO2 films. ? By adding silica to TiO2, the photocatalysis activity of films can be improved. ? Addition of SiO2 can suppress the transformation of anatase to rutile. ? SiO2 addition prevents the growth of TiO2 grains during the sintering process.

  10. Polythiophene thin films electrochemically deposited on sol-gel based TiO2 for photovoltaic applications

    International Nuclear Information System (INIS)

    In this work, the influence of titanium dioxide (TiO2) thin films on the efficiency of organic photovoltaic devices based on electrochemically synthesized polythiophene (PT) was investigated. TiO2 films were produced by sol-gel methods with controlled thickness. The best TiO2 annealing condition was determined through the investigation of the temperature influence on the electron charge mobility and resistivity in a range between 723 K and 923 K. The PT films were produced by chronoamperometric method in a 3-electrode cell under a controlled atmosphere. High quality PT films were produced onto 40 nm thick TiO2 layer previously deposited onto fluorine doped tin oxide (FTO) substrate. The morphology of PT films grown on both substrates and its strong influence on the device performance and PT minimum thickness were also investigated. The maximum external quantum efficiency (IPCE) reached was 9% under monochromatic irradiation (? = 610 nm; 1 W/m2) that is three orders of magnitude higher than that presented by PT-homolayer devices with similar PT thickness. In addition, the open-circuit voltage (Voc) was about 700 mV and the short-circuit current density (Jsc) was 0.03 A/m2 (? = 610 nm; 7 W/m2). However, as for the PT-homolayer also the TiO2/PT based devices are characterized by antibatic response when illuminated through FTO. Finally, the Fill Factor (FF) of t FTO. Finally, the Fill Factor (FF) of these devices is low (25%), indicating that the series resistance (Rs), which is strongly dependent of the PT thickness, is too large. This large Rs value is compensated by TiO2/PT interface morphology and by FTO/TiO2 and TiO2/PT interface phenomena producing preferential paths in which the internal electrical field is higher, improving the device efficiency.

  11. Annealing dependence of residual stress and optical properties of TiO2 thin film deposited by different deposition methods.

    Science.gov (United States)

    Chen, Hsi-Chao; Lee, Kuan-Shiang; Lee, Cheng-Chung

    2008-05-01

    Titanium oxide (TiO(2)) thin films were prepared by different deposition methods. The methods were E-gun evaporation with ion-assisted deposition (IAD), radio-frequency (RF) ion-beam sputtering, and direct current (DC) magnetron sputtering. Residual stress was released after annealing the films deposited by RF ion-beam or DC magnetron sputtering but not evaporation, and the extinction coefficient varied significantly. The surface roughness of the evaporated films exceeded that of both sputtered films. At the annealing temperature of 300 degrees C, anatase crystallization occurred in evaporated film but not in the RF ion-beam or DC magnetron-sputtered films. TiO(2) films deposited by sputtering were generally more stable during annealing than those deposited by evaporation. PMID:18449260

  12. Structural, morphological and local electric properties of TiO2 thin films grown by pulsed laser deposition

    International Nuclear Information System (INIS)

    Titanium dioxide (TiO2) thin films were synthesized on (1 0 0) Si substrates by reactive pulsed laser deposition (PLD) technique. A frequency quadrupled Nd : YAG (? = 266 nm, ?FWHM ? 5 ns, ? = 10 Hz) laser source was used for the irradiations of metallic Ti targets. The experiments were performed in controlled oxygen atmosphere. Crystallinity, surface morphology and local electric properties of the obtained oxide thin films were investigated by x-ray diffractometry, micro-Raman spectroscopy and current sensing atomic force microscopy. An inter-relation was found between the surface morphology, the crystalline structure and the nano-scale electric properties which open the possibility of synthesizing by the PLD technique TiO2 thin films with tunable functional properties for future applications such as photocatalysts, gas sensors or solar energy converters

  13. Photocatalytic degradation of spill oils on TiO2 nanotube thin films

    International Nuclear Information System (INIS)

    The nitrogen-doped TiO2 nanotube (N-TNT) thin films were synthesized using ZnO nanorods as the template and doped with urea at 623 K. Under ultraviolet (UV) and visible light irradiation, the efficiencies for photocatalytic degradation of methylene blue is as high as 30%. About 10% of toluene (representing aromatics in the spill oils) in sea water can be photocatalytically degraded under visible light radiation for 120 min. The aliphatic model compound (1-hexadecene) has, on the contrary, a less efficiency (8%) on the N-TNT photocatalyst. On the average, under visible light radiation, the effectnesses of the N-TNT for photocatalytic degradation of model compounds in the spill oils in sea water are 0.38 mg toluene/gN-TNT h and 0.25 mg 1-hexadecene/gN-TNT h. It is expected that spill oils in the harbors or seashores can be adsorbed and photocatalytically degraded on the N-TNT thin films that are coated onto levee at the sea water surface level

  14. TiO(2)/LiCl-based nanostructured thin film for humidity sensor applications.

    Science.gov (United States)

    Buvailo, Andrii I; Xing, Yangjun; Hines, Jacqueline; Dollahon, Norman; Borguet, Eric

    2011-02-01

    A simple and straightforward method of depositing nanostructured thin films, based on LiCl-doped TiO(2), on glass and LiNbO(3) sensor substrates is demonstrated. A spin-coating technique is employed to transfer a polymer-assisted precursor solution onto substrate surfaces, followed by annealing at 520°C to remove organic components and drive nanostructure formation. The sensor material obtained consists of coin-shaped nanoparticles several hundred nanometers in diameter and less than 50 nm thick. The average thickness of the film was estimated by atomic force microscopy (AFM) to be 140 nm. Humidity sensing properties of the nanostructured material and sensor response times were studied using conductometric and surface acoustic wave (SAW) sensor techniques, revealing reversible signals with good reproducibility and fast response times of about 0.75 s. The applicability of this nanostructured film for construction of rapid humidity sensors was demonstrated. Compared with known complex and expensive methods of synthesizing sophisticated nanostructures for sensor applications, such as physical vapor deposition (PVD) and chemical vapor deposition (CVD), this work presents a relatively simple and inexpensive technique to produce SAW humidity sensor devices with competitive performance characteristics. PMID:21284374

  15. Electrical property measurements of Cr-N codoped TiO2 epitaxial thin films grown by pulsed laser deposition,

    OpenAIRE

    Jacimovic, Jacim; Gaal, Richard; Magrez, Arnaud; Forro?, La?szlo?; Regmi, Mauri; Eres, Gyula

    2013-01-01

    The temperature dependent resistivity and thermo-electric power of Cr-N codoped TiO2 were compared with that of single element N and Cr doped and undoped TiO2 using epitaxial anatase thin films grown by pulsed laser deposition on (100) LaAlO3 substrates. The resistivity plots and especially the thermoelectric power data confirm that codoping is not a simple sum of single element doping. However, the negative sign of the Seebeck coefficient indicates electron dominated transport independent of...

  16. Preparation of anatase TiO2 thin film by low temperature annealing as an electron transport layer in inverted polymer solar cells

    Science.gov (United States)

    Noh, Hongche; Oh, Seong-Geun; Im, Seung Soon

    2015-04-01

    To prepare the anatase TiO2 thin films on ITO glass, amorphous TiO2 colloidal solution was synthesized through the simple sol-gel method by using titanium (IV) isopropoxide as a precursor. This amorphous TiO2 colloidal solution was spread on ITO glass by spin-coating, then treated at 450 °C to obtain anatase TiO2 film (for device A). For other TiO2 films, amorphous TiO2 colloidal solution was treated through solvothermal process at 180 °C to obtain anatase TiO2 colloidal solution. This anatase TiO2 colloidal solution was spread on ITO glass by spin coating, and then annealed at 200 °C (for device B) and 130 °C (for device C), respectively. The average particle size of amorphous TiO2 colloidal solution was about 1.0 nm and that of anatase TiO2 colloidal solution was 10 nm. The thickness of TiO2 films was about 15 nm for all cases. When inverted polymer solar cells were fabricated by using these TiO2 films as an electron transport layer, the device C showed the highest PCE (2.6%) due to the lack of defect, uniformness and high light absorbance of TiO2 films. The result of this study can be applied for the preparation of inverted polymer solar cell using TiO2 films as a buffer layer at low temperature on plastic substrate by roll-to roll process.

  17. Broad band optical characterization of sol-gel TiO2 thin film microstructure evolution with temperature

    International Nuclear Information System (INIS)

    Titanium dioxide (TiO2) thin films have been produced by spin coating a titanium isopropoxide sol on silicon wafer substrates. The structural evolution of the thin films in terms of decomposition, crystallization and densification has been monitored as a function of annealing temperature from 100 to 700 oC using optical characterization and other techniques. The effect of annealing temperature on the refractive index and extinction coefficient of these TiO2 thin films was studied in the range of 0.62 to 4.96 eV photon energy (250-2000 nm wavelength) using spectroscopic ellipsometry. Thermal gravimetric analysis and atomic force microscopy support the ellipsometry data and provide information about structural transformations in the titania thin films with respect to different annealing temperatures. These data help construct a coherent picture of the decomposition of the sol-gel precursors and the creation of dense layers of TiO2. It was observed that the refractive index increased from 2.02 to 2.45 at 2.48 eV (500 nm) in sol-gel spin coated titania films for annealing temperatures from 100 oC to 700 oC.

  18. Microbiology cell-staining wastewater treatment using TiO2 thin films / Tratamiento de agua residual de microbiología usando películas delgadas de TiO2

    Scientific Electronic Library Online (English)

    Jorge A., Fernández; Magda G., Cardozo; Ana K., Carrascal; Juan C., Salcedo; Aura M., Pedroza; Carlos E., Daza.

    2015-06-01

    Full Text Available La fotocatálisis con UV/TiO2 usando películas delgadas fue empleada para el tratamiento de agua residual de microbiología. Se empleó un método simple de sedimentación por gravedad sobre sustrato de vidrio para la preparación de las películas. El uso de Na4P2O7, microondas y ultrasonido fue estudiado [...] para la disminución de los granos de TiO2 en las películas. Se estableció que el mejor método para disminuir los agregados resultó de una combinación de Na4P2O7 (0.01M) y radiación de microondas (700 W, 20 min). Las películas fueron caracterizadas por métodos microscópicos y espectroscópicos. Se obtuvo la fase anatasa (brecha de energía de 3.2 e.V) y tamaños de grano de 83nm. Los ensayos fotocatalíticos utilizando las películas de TiO2generaron un 99.5% de decoloración, 79% de remoción de COT y una inactivación microbiana total luego de 14 h de tratamiento. No se encontró reactivación microbiana luego de 48 h de finalizado el tratamiento Abstract in english Microbiology cell-staining wastewater was treated by UV/TiO2 thin films photocatalysis. A simple method of applying gravity sedimentation over glass-type substrate was used for the preparation of the films. The use of Na4P2O7, microwaves, and ultrasounds were studied for decreasing the TiO2 grain si [...] zes on the films. It was established that the best method for reducing grain size resulted from a combination of Na4P2O7 (0.01M) and microwave radiation (700 W, 20 min). The Films were characterized by several microscopic and spectroscopic methods. Anatase phase (gap energy of 3.2 eV) and grain sizes averaging 83 nm were achieved. Photocatalysis tests using TiO2-films showed 99.5 % of decolorization, 79 % TOC abatement, and total microbial inactivation after 14 h of treatment. No bacteria re-growth was found 48 h after the treatment was completed

  19. Structural and magnetic properties of epitaxial CrO2 thin films grown on TiO2 (001) substrates

    Science.gov (United States)

    Zhang, Xueyu; Zhong, Xing; Visscher, P. B.; LeClair, Patrick R.; Gupta, Arunava

    2013-04-01

    The structural and magnetic properties of epitaxial CrO2 thin films grown on (001)-oriented TiO2 substrates by atmospheric pressure chemical vapor deposition are investigated. Due to the competition between demagnetization and a relatively weak perpendicular magnetocrystalline anisotropy, the deposited CrO2 (001) films exhibit magnetic properties that are significantly different from CrO2 (100) and CrO2 (110) films grown on TiO2 substrates. Based on the thickness dependence of M-H curves, a surface anisotropy is confirmed to exist, likely originating from strain in the film. The out-of-plane hysteresis curves can be well described by a distribution of effective anisotropy that may be due to a varying local demagnetizing field and a distribution of strain across the film. For the in-plane magnetization, the hysteresis curves are consistent with stripe or vortex domain structures of an almost closed flux configuration at remanence.

  20. Structural, morphological, and optical properties of TiO2 thin films synthesized by the electro phoretic deposition technique.

    Science.gov (United States)

    Ghrairi, Najla; Bouaicha, Mongi

    2012-01-01

    In this work, we report the structural, morphological, and optical properties of TiO2 thin films synthesized by the electro phoretic deposition technique. The TiO2 film was formed on a doped fluorine tin oxide (SnO2:F, i.e., FTO) layer and used as a photo electrode in a dye solar cell (DSC). Using spectroscopic ellipsometry measurements in the 200 to 800?nm wavelengths domain, we obtain a thickness of the TiO2 film in the range of 70 to 80?nm. Characterizations by X-ray diffraction and atomic force microscopy (AFM) show a polycrystalline film. In addition, AFM investigation shows no cracks in the formed layer. Using an ultraviolet-visible near-infrared spectrophotometer, we found that the transmittance of the TiO2 film in the visible domain reaches 75%. From the measured current-voltage or I-V characteristic under AM1.5 illumination of the formed DSC, we obtain an open circuit voltage Voc?=?628?mV and a short circuit current Isc?=?22.6??A, where the surface of the formed cell is 3.14?cm2. PMID:22747886

  1. Surface preparation influence on the initial stages of MOCVD growth of TiO2 thin films

    International Nuclear Information System (INIS)

    In situ chemical surface analyses using X-ray photoelectron spectroscopy (XPS), completed by ex situ atomic force microscopy (AFM) analyses, were performed in order to compare the initial stages of MOCVD growth of TiO2 thin films on two different surface types. The first type was a silicon native oxide free hydrogen terminated surface and the second one was a silicon dioxide surface corresponding to a thin layer of 3.5 nm thick in situ thermally grown on silicon substrate. Si(100) was used as substrate, and the growths of TiO2 thin films were achieved with titanium tetraisopropoxide (TTIP) as precursor under a temperature of 675 deg. C, a pressure of 0.3 Pa and a deposition time of 1 h. Whatever the surface is, the deposited titanium amount was globally the same in the two cases. On the contrary, the deposit morphology was different: a covering layer composed of a SiO2 and TiO2 phases mixture on the hydrogen terminated surface, and small TiO2 clusters homogeneously spread on the SiO2 surface

  2. Structural and Electrical Properties of TiO2 Thin Film Derived from Sol-gel Method using Titanium (IV) Butoxide

    OpenAIRE

    Isrihetty Senain; Nafarizal Nayan; Hashim Saim

    2010-01-01

    Fabrication of titanium dioxide (TiO2) thin film on microscope glass using sol-gel method has been studied intensively. The starting materials were titanium (IV) butoxide, ethanol, acetic acid, triton x-100, hydrochloric acid and deionized water. The materials were mixed together to form the sols. Then, the heat and ageing treatment was applied to form stable sols. The sols were then spin coated on the glass substrate to form the homogenous and transparent TiO2 thin film. The TiO2 thin film w...

  3. Effects of LP-MOCVD prepared TiO2 thin films on the in vitro behavior of gingival fibroblasts

    International Nuclear Information System (INIS)

    We report on the in vitro response of human gingival fibroblasts (HGF-1 cell line) to various thin films of titanium dioxide (TiO2) deposited on titanium (Ti) substrates by low pressure metal-organic chemical vapor deposition (LP-MOCVD). The aim was to study the influence of film structural parameters on the cell behavior comparatively with a native-oxide covered titanium specimen, this objective being topical and interesting for materials applications in implantology. HGF-1 cells were cultured on three LP-MOCVD prepared thin films of TiO2 differentiated by their thickness, roughness, transversal morphology, allotropic composition and wettability, and on a native-oxide covered Ti substrate. Besides traditional tests of cell viability and morphology, the biocompatibility of these materials was evaluated by fibronectin immunostaining, assessment of cell proliferation status and the zymographic evaluation of gelatinolytic activities specific to matrix metalloproteinases secreted by cells grown in contact with studied specimens. The analyzed surfaces proved to influence fibronectin fibril assembly, cell proliferation and capacity to degrade extracellular matrix without considerably affecting cell viability and morphology. The MOCVD of TiO2 proved effective in positively modifying titanium surface for medical applications. Surface properties playing a crucial role for cell behavior were the wettability and, secondarily, the roughness, HGF-1ity and, secondarily, the roughness, HGF-1 cells preferring a moderately rough and wettable TiO2 coating.

  4. Properties of sputtered TiO2 thin films as a function of deposition and annealing parameters

    Science.gov (United States)

    Pjevi?, Dejan; Obradovi?, Marko; Marinkovi?, Tijana; Grce, Ana; Milosavljevi?, Momir; Grieseler, Rolf; Kups, Thomas; Wilke, Marcus; Schaaf, Peter

    2015-04-01

    The influence of sputtering parameters and annealing on the structure and optical properties of TiO2 thin films deposited by RF magnetron sputtering is reported. A pure TiO2 target was used to deposit the films on Si(100) and glass substrates, and Ar/O2 gas mixture was used for sputtering. It was found that both the structure and the optical properties of the films depend on deposition parameters and annealing. In all cases the as-deposited films were oxygen deficient, which could be compensated by post-deposition annealing. Changes in the Ar/O2 mass flow rate affected the films from an amorphous-like structure for samples deposited without oxygen to a structure where nano-crystalline rutile phase is detected in those deposited with O2. Annealing of the samples yielded growth of both, rutile and anatase phases, the ratio depending on the added oxygen content. Increasing mass flow rate of O2 and annealing are responsible for lowering of the energy band gap values and the increase in refractive index of the films. The results can be interesting towards the development of TiO2 thin films with defined structure and properties.

  5. Electrophoretic deposited TiO2 pigment-based back reflectors for thin film solar cells.

    Science.gov (United States)

    Bills, Braden; Morris, Nathan; Dubey, Mukul; Wang, Qi; Fan, Qi Hua

    2015-02-01

    Highly reflective coatings with strong light scattering effect have many applications in optical components and optoelectronic devices. This work reports titanium dioxide (TiO2) pigment-based reflectors that have 2.5 times higher broadband diffuse reflection than commercially produced aluminum or silver based reflectors and result in efficiency enhancements of a single-junction amorphous Si solar cell. Electrophoretic deposition is used to produce pigment-based back reflectors with high pigment density, controllable film thickness and site-specific deposition. Electrical conductivity of the pigment-based back reflectors is improved by creating electrical vias throughout the pigment-based back reflector by making holes using an electrical discharge / dielectric breakdown approach followed by a second electrophoretic deposition of conductive nanoparticles into the holes. While previous studies have demonstrated the use of pigment-based back reflectors, for example white paint, on glass superstrate configured thin film Si solar cells, this work presents a scheme for producing pigment-based reflectors on complex shape and flexible substrates. Mechanical durability and scalability are demonstrated on a continuous electrophoretic deposition roll-to-roll system which has flexible metal substrate capability of 4 inch wide and 300 feet long. PMID:25836255

  6. Photocatalytic effect of the sol-gel derived nanoporous TiO2 transparent thin films

    International Nuclear Information System (INIS)

    Photocatalytically active nanoporous anatase TiO2 films were deposited on glass plates by a sol-gel process conducted in the presence of polyethylene glycol (PEG). The films in different stages of the formation process were characterized by field emission scanning electron microscope, thermogravimetry-differential thermal analysis, ultraviolet-visible (UV-visible) spectroscopy and X-ray diffraction. The as-deposited TiO2/PEG composite films were smooth and dense, and were made nanoporous after the embedded PEG was thermally removed during calcination. The higher the content of PEG the larger was the resultant pore size. There were no cracks in the films common to films prepared in the presence of PEG, and the thermal stability of the films were also improved by the PEG addition. UV-visible spectroscopy showed that the calcination of PEG-TiO2 films also resulted in red shifting the absorption band of TiO2. The films were active in the photooxidation of iodide and methyl orange, and demonstrated an activity increase that scaled with the increase in the PEG content in the sol-gel preparation

  7. TRANSPARENT SUPERHYDROPHILIC SiO2/TiO2/SiO2 TRI-LAYER NANOSTRUCTURED ANTIFOGGING THIN FILM

    OpenAIRE

    Eshaghi A.; Aghaei A. A.; Zabolian H.; Jannesari M; Firoozifar A.

    2013-01-01

    SiO2/TiO2/SiO2 thin films were deposited on glass substrates using an electron beam physical vapor deposition technique. The structure, morphology, surface composition, surface roughness, optical properties, and hydrophilic properties of the thin film were investigated. The structure measurement shows that only anatase phase was exhibited in the thin film. In the TiO2 thin film, the crystals nucleated from the thin films was homogeneous and the average crystalline sizes were 35 nm. The transm...

  8. Influence of thickness and air annealing on structural, morphological, compositional, electrical properties of sprayed TiO2 thin films

    Directory of Open Access Journals (Sweden)

    R.SHASHIDHAR

    2013-04-01

    Full Text Available TiO2 thin films were prepared by spray pyrolysis technique at a substrate temperature of 3500C under optimum conditions. Films have uniform thickness varying from 0.3–6 ?m and good adhesion to substrate. The films were characterized by XRD, SEM and EDAX measurements. XRD profile shows poly crystalline nature of films. As deposited films have anatase phase. Transformation from anatase to anatase–rutile mixed phase may be due to annealing at 4000C and thickness variation of films. The microstructural properties such as crystallite size, microstrain and dislocation density found to increase due to concentration of lattice imperfections and crystallization of amorphous TiO2 films. SEM micrographs exhibit spherical, square, flower shaped grains and grain boundary formation. EDAX analysis revealed the formation of stoichiometric TiO2 films. Electrical studies show that the films are of n-type nature and increase in resistivity is attributed to surface oxidation and formation of Ti2O3 structure, a perfect insulator.

  9. An unconventional route to high-efficiency dye-sensitized solar cells via embedding graphitic thin films into TiO2 nanoparticle photoanode.

    Science.gov (United States)

    Jang, Yoon Hee; Xin, Xukai; Byun, Myunghwan; Jang, Yu Jin; Lin, Zhiqun; Kim, Dong Ha

    2012-01-11

    Graphitic thin films embedded with highly dispersed titanium dioxide (TiO(2)) nanoparticles were incorporated for the first time into the conventional dye-sensitized solar cells (DSSCs), resulting in a remarkably improved cell efficiency due to its superior electron conductivity. Massively ordered arrays of TiO(2) dots embedded in carbon matrix were fabricated via UV-stabilization of polystyrene-block-poly(4-vinylpyridine) films containing TiO(2) precursors followed by direct carbonization. For dye-sensitized TiO(2) based solar cells containing carbon/TiO(2) thin layers at both sides of pristine TiO(2) layer, an increase of 62.3% [corrected] in overall power conversion efficiency was achieved compared with neat TiO(2)-based DSSCs. Such a remarkably improved cell efficiency was ascribed to the superior electron conductivity and extended electron lifetime elucidated by cyclic voltammetry and impedance spectroscopy. PMID:22148913

  10. Thickness-dependent photocatalytic performance of nanocrystalline TiO2 thin films prepared by sol-gel spin coating

    Science.gov (United States)

    Wu, Chung-Yi; Lee, Yuan-Ling; Lo, Yu-Shiu; Lin, Chen-Jui; Wu, Chien-Hou

    2013-09-01

    TiO2 nanocrystalline thin films on soda lime glass have been prepared by sol-gel spin coating. The thin films were characterized for surface morphology, crystal structure, chemical composition, thickness, and transparency by atomic force microscopy (AFM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), ellipsometry, and UV-vis spectrophotometry. The films prepared by titanium tetraisopropoxide (TTIP) as the precursor under pH of 3.5 ± 0.5 and with calcination temperature of 450 ?C for 3 h exhibited superior homogeneous aggregation, good optical transparency, superhydrophilicity, and reliable thickness. The effect of film thickness on the photocatalytic degradation of acid yellow 17 was investigated under UV irradiation. The photocatalytic activity was strongly correlated with the number of coatings and followed Langmuir-type kinetics. Under the same film thickness, TiO2 thin films prepared by 0.1 M TTIP exhibited more efficient photocatalytic activity than those prepared by 0.3 M TTIP. For thin films prepared by 0.1 M TTIP, the maximum specific photocatalytic activity occurred at 5 coatings with thickness of 93 ± 1 nm. A model was proposed to rationalize the dependence of the film thickness on the photocatalytic activity, which predicts the existence of an optimum film thickness.

  11. Thickness-dependent photocatalytic performance of nanocrystalline TiO2 thin films prepared by sol–gel spin coating

    International Nuclear Information System (INIS)

    TiO2 nanocrystalline thin films on soda lime glass have been prepared by sol–gel spin coating. The thin films were characterized for surface morphology, crystal structure, chemical composition, thickness, and transparency by atomic force microscopy (AFM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), ellipsometry, and UV–vis spectrophotometry. The films prepared by titanium tetraisopropoxide (TTIP) as the precursor under pH of 3.5 ± 0.5 and with calcination temperature of 450oC for 3 h exhibited superior homogeneous aggregation, good optical transparency, superhydrophilicity, and reliable thickness. The effect of film thickness on the photocatalytic degradation of acid yellow 17 was investigated under UV irradiation. The photocatalytic activity was strongly correlated with the number of coatings and followed Langmuir-type kinetics. Under the same film thickness, TiO2 thin films prepared by 0.1 M TTIP exhibited more efficient photocatalytic activity than those prepared by 0.3 M TTIP. For thin films prepared by 0.1 M TTIP, the maximum specific photocatalytic activity occurred at 5 coatings with thickness of 93 ± 1 nm. A model was proposed to rationalize the dependence of the film thickness on the photocatalytic activity, which predicts the existence of an optimum film thickness.

  12. DIRECT PHOTODEPOSITION OF NANOSTRUCTURED TIO2 THIN FILMS FROM B-DIKETONATE COMPLEXES, AND THEIR PHOTOCATALYTIC BEHAVIOUR

    Directory of Open Access Journals (Sweden)

    M TEJOS

    2004-12-01

    Full Text Available Amorphous Titania thin films have been photochemically obtained by direct UV irradiation (254 nm of an amorphous TiO(C6H5COCHCOCH3 2 film spin-coated on Si(100 and borosilicate glass. These materials were characterized by scanning electron microscopy (SEM, X-ray diffraction spectroscopy (XRD and Auger electron spectroscopy (AES. SEM analysis showed a porous film with irregular morphology (diameter < 300 nm, whereas the XRD spectrum showed that the as-deposited film was completely amorphous and was transformed by annealing under nitrogen into polycrystalline TiO2. Subsequently, amorphous Titania deposited on borosilicate glass was used in the photocatalytic decomposition of aniline in water. The photoreaction of aniline was monitored by UV in the presence of air and nitrogen, and the product was characterized by infrared spectroscopy (IR. The results showed that aniline can be photooxidized efficiently by the TiO2/ borosilicate system in the presence of oxygen

  13. A simple and low temperature process for super-hydrophilic rutile TiO2 thin films growth

    International Nuclear Information System (INIS)

    We investigate an environmentally friendly aqueous solution system for rutile TiO2 violet color nanocrystalline thin films growth on ITO substrate at room temperature. Film shows considerable absorption in visible region with excitonic maxima at 434 nm. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), UV-vis, water surface contact angle and energy dispersive X-ray analysis (EDX) techniques in addition to actual photo-image that shows purely rutile phase of TiO2 with violet color, super-hydrophilic and densely packed nanometer-sized spherical grains of approximate diameter 3.15 ± 0.4 nm, characterize the films. Band gap energy of 4.61 eV for direct transition was obtained for the rutile TiO2 films. Film surface shows super-hydrophilic behavior, as exhibited water contact angle was 7o. Strong visible absorption (not due to chlorine) leaves future challenge to use these films in extremely thin absorber (ETA) solar cells

  14. Evolution of structural and optical properties of photocatalytic Fe doped TiO2 thin films prepared by RF magnetron sputtering

    International Nuclear Information System (INIS)

    Undoped and Fe doped TiO2 thin films have been prepared by RF magnetron sputtering. Pure TiO2 thin film exhibited an amorphous-like nature. With increase in iron concentration (0–0.1 at%), the films exhibited better crystallization to anatase phase . Red shift of absorption edge was observed in the UV-vis transmittance spectra . At higher Fe concentration (0.5 at%), onset of phase transformation to rutile is noticed. Photocatalytic properties of pure and 0.1 at% Fe doped TiO2 thin films were investigated by degradation of methylene blue in UV light, visible light and light from Hg vapor lamp. 70% degradation of methylene blue was observed in the presence of Fe doped film in comparison with 3% degradation in presence of pure TiO2 film when irradiated using visible light for 2 h

  15. Influence of calcination ambient and film thickness on the optical and structural properties of sol-gel TiO2 thin films

    International Nuclear Information System (INIS)

    Influence of both calcination ambient and film thickness on the optical and structural properties of sol-gel derived TiO2 thin films have been studied. X-ray diffraction results show that prepared films are in an anatase form of TiO2. Films calcined in argon or in low vacuum (?2 x 10-1 mbar) are found to be smaller in crystallite size, more transparent at low wavelength region of ?300-450 nm, denser, have higher refractive index and band gap energy compared to air-calcined films. Scanning electron microscopic study reveals that surfaces of TiO2 films calcined in argon or in low vacuum are formed by densely packed nano-sized particulates. Presence of voids and signs of agglomeration can be seen clearly in the surface microstructure of air-calcined films. In the thickness range ?200-300 nm, band gap energy and crystallite size of TiO2 films remain practically unaffected with film thickness but refractive index of thinner film is found to be marginally higher than that of thicker film. In this work, it has been shown that apart from temperature and soaking time, partial pressure of oxygen of the ambient is also an important parameter by which crystallite size, microstructure and optical properties of the TiO2 films may be tailored during calcination period

  16. Effect of thermal annealing on the structural properties of TiO2 thin film prepared by RF sputtering

    International Nuclear Information System (INIS)

    It was presented the structural properties of a titanium dioxide thin film which is prepared by RF magnetron sputtering system on p-type (100) Si substrate with Ar (70 percent) and O (30 percent) atmosphere. The film was conventionally thermal annealed at 500 degrees Celsius, 800 degrees Celsius, 1000 degrees Celsius during 1 hour and 1000 degrees Celsius during 2 hours under air atmosphere. The structural properties of films were investigated by using high resolution x-ray diffraction system and Fourier transform infrared spectroscopy in range from 375 to 8000 sm-1 for as-deposited films and annealed films. Also, chemical bonding structures of the thin film were explained. As-deposited film has anatase phase. However, in annealed films anatase and rutile phases coexist as revealed by XRD and infrared spectroscopy. Also, it is observed that during growth and the annealing of the TiO2 film, thin SiO2 layer was formed at the TiO2 and Si interface

  17. TRANSPARENT SUPERHYDROPHILIC SiO2/TiO2/SiO2 TRI-LAYER NANOSTRUCTURED ANTIFOGGING THIN FILM

    Directory of Open Access Journals (Sweden)

    Eshaghi A.

    2013-09-01

    Full Text Available SiO2/TiO2/SiO2 thin films were deposited on glass substrates using an electron beam physical vapor deposition technique. The structure, morphology, surface composition, surface roughness, optical properties, and hydrophilic properties of the thin film were investigated. The structure measurement shows that only anatase phase was exhibited in the thin film. In the TiO2 thin film, the crystals nucleated from the thin films was homogeneous and the average crystalline sizes were 35 nm. The transmittance spectra of the films revealed transparency in the visible region of the spectrum. SiO2/TiO2/SiO2 thin film showed better hydrophilicity under irradiation and storage in comparison to SiO2/TiO2 thin film. SiO2/TiO2/SiO2 tri-layer thin film showed superhydrophilicity which greatly encourages the antifogging function of the film.

  18. Hysteretic current-voltage characteristics in RF-sputtered nanocrystalline TiO2 thin films

    International Nuclear Information System (INIS)

    We have measured the current-voltage characteristics at room temperature of a nanocrystalline TiO2 thin film fabricated by reactive RF-sputtering deposition and sandwiched between ITO (indium-tin-oxide)-buffered glass substrate and an indium top electrode. The I-V characteristics are ohmic for low voltages and become non-linear, hysteretic and asymmetric as the voltage is increased. The system is shown to be well represented by two distinct resistance states in the non-ohmic region. Current transient evolutions were also measured for constant voltage excitations. The resistance is stable in time for voltages in the ohmic regime. In contrast, for voltages in the non-ohmic regime, the resistance has a small variation for a short period of time (order of tens seconds) and then increases with time. For those transients, long characteristic times (on the order of tens of minutes up to hours) were found. The behavior of the system is discussed on the basis of experimental results reported in the literature for similar systems and existing models for electric-field induced resistive switching

  19. Localised modifications of anatase TiO2 thin films by a Focused Ion Beam

    International Nuclear Information System (INIS)

    A Focused Ion Beam (FIB) has been used to implant micrometer-sized areas of polycrystalline anatase TiO2 thin films with Ga+ ions using fluencies from 1015 to 1017 ions/cm2. The evolution of the surface morphology was studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM). In addition, the chemical modifications of the surface were followed by X-ray photoelectron spectroscopy (XPS). The implanted areas show a noticeable change in surface morphology as compared to the as-deposited surface. The surface loses its grainy morphology to gradually become a smooth surface with a RMS roughness of less than 1 nm for the highest ion fluence used. The surface recession or depth of the irradiated area increases with ion fluence, but the rate with which the depth increases changes at around 5 x 1016 ions/cm2. Comparison with implantation of a pre-irradiated surface indicates that the initial surface morphology may have a large effect on the surface recession rate. Detailed analysis of the XPS spectra shows that the oxidation state of Ti and O apparently does not change, whereas the implanted gallium exists in an oxidation state related to Ga2O3.

  20. Andreev spectroscopy of CrO$_{2}$ thin films on TiO$_{2}$ and Al$_{2}$O$_{3}$

    OpenAIRE

    Yates, KA; Anwar, MS; Aarts, J.; Conde, O.; Eschrig, M; Löfwander, T.; Cohen, LF

    2013-01-01

    Here we analyse the spectroscopic information gathered at a number of single CrO$_{2}$ / Pb interfaces. We examine thin films requiring additional interfacial layers to generate long range spin triplet proximity effect superconductivity (CrO$_{2}$/TiO$_{2}$) or not (CrO$_{2}$/Al$_{2}$O$_{3}$). We analyse the data using two theoretical models and explore the use of a parameter free method to determine the agreement between the models and experimental observations, showing the...

  1. Potentiostatic reversible photoelectrochromism: an effect appearing in nanoporous TiO2/Ni(OH)2 thin films.

    Science.gov (United States)

    Cibrev, Dejan; Jankulovska, Milena; Lana-Villarreal, Teresa; Gómez, Roberto

    2014-07-01

    In the field of energy saving, finding composite materials with the ability of coloring upon both illumination and change of the applied electrode potential keeps on being an important goal. In this context, chemical bath deposition of Ni(OH)2 into nanoporous TiO2 thin films supported on conducting glass leads to electrodes showing both conventional electrochromic behavior (from colorless to dark brown and vice versa) together with photochromism at constant applied potential. The latter phenomenon, reported here for the first time, is characterized by fast and reversible coloration upon UV illumination. The bleaching kinetics shows first order behavior with respect to the Ni(III) centers in the film, and an order 1.2 with respect to electrons in the TiO2 film. From a more applied point of view, this study opens up the possibility of having two-mode smart windows showing not only conventional electrochromism but also reversible darkening upon illumination. PMID:24926989

  2. Production of multicharged iron and nitrogen ions and application to enhance photo-catalytic performance in visible light region on TiO2 thin films

    International Nuclear Information System (INIS)

    Multicharged iron and nitrogen ions have been produced from solid materials in a 2.45 GHz electron cyclotron resonance (ECR) ion source (TAIKO device, Toyama Prefectural University), and also large area TiO2 thin films are individually produced by reactive sputtering in an arched ECR plasma. We normally form the TiO2 thin film (?100 nm) on the Si(1 0 0) substrates. We measure the X-ray diffraction for characterization of the TiO2 crystallinity and the contact angle of distilled water for estimation of photo-catalytic performance. The crystalline TiO2 thin films are anatase and rutile phases. Fe3+ and N3+ ions were implanted into TiO2 thin films on the Si substrates in order to enhance photo-catalytic performance in visible light region. The maximum efficiency of photo-catalytic performance has been obtained at the dose of about 2 x 1015 cm-2. We compared contact angles of distilled water on the TiO2 by illuminating fluorescent light for four hours before and after implantation. Photo-catalytic performance of the TiO2 thin film in visible light region after implantation is better than that before implantation without deterioration in ultraviolet light region

  3. Laser reactivation of Room- T c ferromagnetism in Mn-doped insulating TiO2 thin films

    Science.gov (United States)

    Xu, L. M.; Xing, X. J.; Yang, M.; Li, X. Y.; Wu, S. X.; Hu, P.; Lu, J. Q.; Li, S. W.

    2010-02-01

    Room- T c ferromagnetic insulating Mn-doped TiO2 thin films were prepared by plasma assisted molecular beam epitaxy (PAMBE). The thin films show obvious decay of ferromagnetism when aged in air at room temperature for one year without any special treatment. A distinct reactivation of ferromagnetism, together with a decrease in coercive force is achieved in these samples under laser irradiation treatment. The possible mechanism for the phenomena is also discussed. It is suggested that the bound magnetic polaron (BMP) forming via photo-generated defect-bound carriers accounts for the laser reactivation of room- T c ferromagnetism.

  4. An electrochemical strategy to incorporate nitrogen in nanostructured TiO2 thin films: modification of bandgap and photoelectrochemical properties

    International Nuclear Information System (INIS)

    We describe a simple and facile electrochemical method to introduce anionic dopants into TiO2. N-doped thin films with chemical composition TiO2-xNx, up to x = 0.23, were fabricated by anodic oxidation of a pure titanium sheet in electrolyte solutions containing ammonium ions, nitrate ions and fluoride ions enabling simultaneous nanostructuring and doping of the growing anodic oxide. Analysis by x-ray photoelectron spectroscopy (XPS) indicates that nitrogen atoms substitute for oxygen sites within the TiO2. F atoms were present in the amorphous, as-anodized samples but were resubstituted by O atoms upon annealing in oxygen at temperatures higher than 600 deg. C. For nitrogen doped films UV-vis spectroscopy indicates a shift in the primary absorption threshold as well as significant optical absorption in the visible wavelength range from 400 to 530 nm. The concentration of the incorporated anionic dopants, and the morphology of the doped thin film are strong functions of electrolyte chemistry and anodization time. Longer anodization periods resulted in a well-developed nanotube-array structure but smaller amounts of incorporated nitrogen. XPS depth profiling reveals the nitrogen doping to be inhomogeneous, with maximum nitrogen incorporation occurring near the oxide-electrolyte interface at the surface of the anodized film

  5. Structural evolution of TiO2 nanocrystalline thin films by thermal annealing and swift heavy ion irradiation

    International Nuclear Information System (INIS)

    The present study probes into the transition from anatase to rutile phase of TiO2 in 100 nm thick nanocrystalline thin films under thermal annealing and swift heavy ion (SHI) irradiation. The films were prepared using sol-gel and spin coating techniques on silicon (100) substrates. The as-deposited films are found to be amorphous by glancing angle x-ray diffraction and Raman spectroscopy. Though thermal annealing is known to cause transformation from anatase to rutile phase of TiO2 in a temperature interval of 700-900 deg. C, in nanoparticle thin films, we found that a sizable volume fraction of anatase still remains even after annealing at 1000 deg. C. Irradiations by 200 MeV Ag ions on the other hand suppressed the anatase phase and almost phase pure rutile TiO2 could be obtained at a fluence of 3x1012 ions cm-2. A mechanism based on the competing effect of grain growth and conversion of anatase to rutile at the grain boundary of the anatase on annealing and conversion of anatase to rutile in the grains of the anatase due to SHI induced thermal spike is proposed to explain the observed result

  6. Enhancement of photoelectric and photocatalytic activities: Mo doped TiO2 thin films deposited by sputtering

    International Nuclear Information System (INIS)

    TiO2 thin films doped with different contents of Mo were deposited by DC reactive magnetron sputtering. Surface morphology, crystal structure, elements' valence states and absorption edge of each sample were characterized by atomic force microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and ultraviolet–visible spectrometer. Cyclic voltammetry was utilized to study the photoelectric properties while the photocatalytic activity was evaluated by the degradation rate of methylene blue. The result indicates that an appropriate concentration of Mo could extend the absorption edge of TiO2 film to visible range remarkably. When the content reached 0.9 at.%, with a xenon lamp we observed the strongest photocurrent as well as the best photocatalytic property while under the illumination of strong visible light, a photocurrent 10 times the undoped sample appeared. The electrochemical impedance spectroscopy observed the fastest speed of carrier transfer as doping content increased to 0.9 at.%, while higher doping amount would precipitate carrier recombination due to a large number of lattice defects. - Highlights: ? Mo-doped TiO2 thin films were deposited by DC reactive magnetron sputtering. ? Doped films present high specific area and well-grown crystals. ? Proper content of Mo accelerates charge separation and inhibits the recombination. ? Enhanced photocatalytic activity under ultraviolet light is attained by doping. light is attained by doping. ? Under visible light, the strongest photocurrent after doping increases tenfold!

  7. Semiconductor TiO2-Ga2O3 thin film gas sensors derived from particulate sol-gel route

    International Nuclear Information System (INIS)

    Nanostructured and mesoporous TiO2-Ga2O3 thin films with various Ti:Ga atomic ratios were prepared by a new straightforward particulate sol-gel route. Titanium isopropoxide and gallium (III) nitrate hydrate were used as precursors, and hydroxypropyl cellulose (HPC) was used as a polymeric fugitive agent (PFA) in order to increase the specific surface area (SSA). XRD and TEM analysis of the powders revealed that the Ga2O3 formed from the nitrate precursor retarded anatase-to-rutile transformation, crystallization and crystal growth. The average crystallite size of pure TiO2 powder annealed at 600-1000 deg. C were in the range 4-10 nm; the values that could be decreased to 2-6 nm for TiO2-Ga2O3 powders. Furthermore, one of the highest SSA was obtained by introducing Ga2O3 into TiO2, being 305 m2 g-1 for TG11 (Ti:Ga = 50:50 atomic ratio) binary oxide annealed at 600 deg. C. Thin films produced under optimized conditions showed excellent microstructural properties for gas sensing applications. They exhibited a remarkable response towards low concentrations of CO and NO2 gases at low operating temperature of 200 deg. C, resulting in increased thermal stability of sensing films as well as a decrease in their power consumption. TG11 sensor showed the highest response towards all CO and NO2 concentratiords all CO and NO2 concentrations operated at 200 deg. C. The response magnitude of 13.7 and 4.3 with response times of 30 s and 108 s were achieved for TG11 sensor towards 400 ppm CO and 10 ppm NO2, respectively. Furthermore, calibration curves revealed that TiO2-Ga2O3 sensors follow the power law (S = A[gas] B) (where S is sensor response, coefficients A and B are constants and [gas] is gas concentration) for the two types of gases, and they have excellent capability for the detection of low gas concentrations (25 ppm CO and 0.5 ppm NO2). The maximum response of TiO2-Ga2O3 sensors towards CO and NO2 was measured at 450 and 400 deg. C, respectively. The sensor response decreased with increasing film annealing temperature owing to sintering of the particles. The response magnitude and response time of the sensors obtained in this work is superior to TiO2-based sensors reported in previous studies

  8. Electrical and optical properties of the hybrid TiO2 nanocrystals - MEH-PPV thin films

    International Nuclear Information System (INIS)

    Recently, the conjugated polymer-inorganic nanocomposites have been increasingly studied because of their enhanced optical and electronic properties as well as their potential application in developing optoelectronic devices. In this study nanocomposite materials thin films based on poly [2-methoxy-5-(2-ethyl-hexyloxy) - 1,4- phenylene vinylene] (MEH-PPV) and nanocrystalline TiO2 (nc-TiO2) have been fabricated. The photoluminescence (PL) spectra of pure MEN-PPV and nanohybrid films have shown that the excitation at a 377 nm wavelength leads to the strongly enhanced performance in photoluminescent intensity due to the compositions of TiO2 component. Current-voltage (I-V) characteristics of multi-layer device Al/ /MEH-PPV; nc-TiO2/ /PEDOT: PSS/ /ITO/ /glass were investigated. the results show that the hybrid MEH-PPV: nc-TiO2 materials with high concentrations of TiO2 (>25 %) can be expected to be a good candidate for photovoltaic solar cell applications whereas hose with lower concentrations of TiO2 are more suitable for organic light-emitting diodes (OLEDs). (author)

  9. The structure and photocatalytic activity of TiO2 thin films deposited by dc magnetron sputtering

    Science.gov (United States)

    Yang, W. J.; Hsu, C. Y.; Liu, Y. W.; Hsu, R. Q.; Lu, T. W.; Hu, C. C.

    2012-12-01

    This paper seeks to determine the optimal settings for the deposition parameters, for TiO2 thin film, prepared on non-alkali glass substrates, by direct current (dc) sputtering, using a ceramic TiO2 target in an argon gas environment. An orthogonal array, the signal-to-noise ratio and analysis of variance are used to analyze the effect of the deposition parameters. Using the Taguchi method for design of a robust experiment, the interactions between factors are also investigated. The main deposition parameters, such as dc power (W), sputtering pressure (Pa), substrate temperature (°C) and deposition time (min), were optimized, with reference to the structure and photocatalytic characteristics of TiO2. The results of this study show that substrate temperature and deposition time have the most significant effect on photocatalytic performance. For the optimal combination of deposition parameters, the (1 1 0) and (2 0 0) peaks of the rutile structure and the (2 0 0) peak of the anatase structure were observed, at 2? ˜ 27.4°, 39.2° and 48°, respectively. The experimental results illustrate that the Taguchi method allowed a suitable solution to the problem, with the minimum number of trials, compared to a full factorial design. The adhesion of the coatings was also measured and evaluated, via a scratch test. Superior wear behavior was observed, for the TiO2 film, because of the increased strength of the interface of micro-blasted tools.

  10. Co-doped TiO2 thin films studied by magnetic resonance technique

    International Nuclear Information System (INIS)

    TiO2 thin films with different Co nanoparticle content were prepared by reactive co-sputtering onto Si (100) substrates. The films thicknesses were in range of 200 to 330 nm. Electron probe microanalysis showed the Co content (x) of the Ti1-xCoxO2 samples was 2.2, 3.0, 4.4, 6.5, and 8.5 %. X-ray diffraction measurements revealed polycrystalline Rutile structure of the samples. Magnetization measurements showed hysteresis behavior for all samples with the coercive field in range of 55 - 65 Oe. The saturation magnetization at room temperature ranged from 7 emu/cm''3 (2.2 % Co) to 28 emu/cm''3 (8.5 % Co). X-band (9.5 GHz) Electron Spin Resonance measurements were performed as a function of the sample orientation and temperature. Weak ESR signals that depended on Co content were observed at room temperature. Different contributions to the room temperature spectra were attributed to super-paramagnetic cobalt particles, some ferromagnetic phase in the sample, and paramagnetic impurities in silicon substrate. Very strong temperature dependence of ESR spectra has been observed in all samples. The room temperature signals decreased with cooling, and vanished at lowest temperatures. A very broad signal appeared with cooling, dramatically intensified at about 50-80K, and then decreased at lowest temperature (10K). A kind of phase transition in the temperature behavior of the intensity was observed in the temperature range of 50-60K. We attribute this behavior to unconventional spin-glass-like ordering realized in the system. The results received are important for understanding the tunnel magnetoresistance behavior of such systems

  11. Visible-light photocatalytic activity of nitrogen-doped TiO2 thin film prepared by pulsed laser deposition

    International Nuclear Information System (INIS)

    Nitrogen-doped titanium dioxide (TiO2-xNx) thin films have been prepared by pulse laser deposition on quartz glass substrates by ablated titanium dioxide (rutile) target in nitrogen atmosphere. The x value (nitrogen concentration) is 0.567 as determined by X-ray photoelectron spectroscopy measurements. UV-vis spectroscopy measurements revealed two characteristic deep levels located at 1.0 and 2.5 eV below the conduction band. The 1.0 eV level is attributable to the O vacancy state and the 2.5 eV level is introduced by N doping, which contributes to narrowing the band-gap by mixing with the O2p valence band. The enhanced degradation efficiency in a broad visible-light range was observed from the degradation of methylene blue and methylene orange by the TiO2-xNx film

  12. Influência do tipo de ácido e tempo de envelhecimento na atividade fotocatalítica de filmes finos de TiO2 Type of acid and ageing effect influence on photocatalytic activity of TiO2 thin films

    Directory of Open Access Journals (Sweden)

    Liana Key Okada Nakamura

    2011-01-01

    Full Text Available TiO2 thin films were prepared by the sol-gel method using different acids (HCl and HAc, with a parallel evaluation of the gel ageing effects on the film properties. After the thermal treatments, the resulting materials were characterized through gravimetric analysis, UV-VIS spectrophotometry (from which optical parameters such as band gap was derived, XRD, morphological surface analysis (AFM and photocatalytic activity. The majority of the obtained thin films parameters were similar independent of the acid type and the ageing time of the gel. Nevertheless, a visible effect of the surface morphology properties on the films and their photocatalytic activity was observed.

  13. Influência do tipo de ácido e tempo de envelhecimento na atividade fotocatalítica de filmes finos de TiO2 / Type of acid and ageing effect influence on photocatalytic activity of TiO2 thin films

    Scientific Electronic Library Online (English)

    Liana Key Okada, Nakamura; Jorge Moreira, Vaz.

    1173-11-01

    Full Text Available [...] Abstract in english TiO2 thin films were prepared by the sol-gel method using different acids (HCl and HAc), with a parallel evaluation of the gel ageing effects on the film properties. After the thermal treatments, the resulting materials were characterized through gravimetric analysis, UV-VIS spectrophotometry (from [...] which optical parameters such as band gap was derived), XRD, morphological surface analysis (AFM) and photocatalytic activity. The majority of the obtained thin films parameters were similar independent of the acid type and the ageing time of the gel. Nevertheless, a visible effect of the surface morphology properties on the films and their photocatalytic activity was observed.

  14. Effects of TiO2 Interlayers on the Optical Switching of VO2 Thin Films Grown by Sol-Gel Process

    Directory of Open Access Journals (Sweden)

    ZHANG Yu-Bo, HUANG Wan-Xia, SONG Lin-Wei, YAN Jia-Zhen, SHI Qi-Wu, ZHANG Yang

    2013-02-01

    Full Text Available Thermochromic VO2 and VxW1-xO2 films were deposited on TiO2/mica substrates. The TiO2/mica substrates were fabricated via Sol-Gel process, and the hydrophilicity of the TiO2/mica substrate was improved under UV light irradiated. The V2O5 sol was deposited on the TiO2/mica substrate by the spin coating method, and then it was annealed. SEM and XRD analysis were applied to analyze the morphology, phases and microstructure of the films. FTIR was used to study the thermochromic properties. The results suggest that VO2/TiO2 grow preferentially along single orientation. VxW1-xO2/TiO2 composite film is impossible to fabricate single orientation films. TiO2 interlayers are favorable to compact the VO2 thin films and reduce the transition temperature. It will make the hysteresis width of VxW1-xO2/TiO2 composite film reduce to about 4¡?articularly.

  15. The FTIR studies of gels and thin films of Al2O3-TiO2 and Al2O3-TiO2-SiO2 systems.

    Science.gov (United States)

    Adamczyk, Anna; D?ugo?, El?bieta

    2012-04-01

    In this work, samples in form of bulk ones and thin films were obtained using the sol-gel method. The bulk samples were heated at different temperatures (500 °C, 850 °C and 1100 °C) corresponding to the annealing process of coatings, deposited on different substrates by dipping and pulling out samples from the proper sol with the stable speed. Thin films of both Al2O3-TiO2 and Al2O3-TiO2-SiO2 systems were deposited on carbon, steel and titanium substrates in two different ways: as single layers obtained from Al2O3 sol, TiO2 sol and Al2O3 sol or deposited as mixed coatings from Al2O3-TiO2 sol as well as Al2O3-TiO2-SiO2 one. All bulk samples were studied by the FTIR spectroscopy and the X-ray diffractometry while thin films were also investigated by the electron microscopy. In the IR spectra of Al2O3-TiO2 samples, as well as gels and coatings, bands due to the vibrations of AlO bonds of the octahedrally and tetrahedrally coordinated aluminum were observed. The IR spectra of samples of Al2O3-TiO2-SiO2 system differ from that of Al2O3-TiO2 ones in presence of bands assigned to the SiO bond vibrations and in positions of bands due to AlO bond vibrations. In all spectra of bulk samples and coatings, the positions of TiO bond vibrations were ascribed basing on the IR spectra of the pure anatase and rutile. PMID:22240231

  16. The antibacterial and hydrophilic properties of silver-doped TiO2 thin films using sol-gel method

    International Nuclear Information System (INIS)

    Ag-TiO2 composite thin films were deposited on glass slides by sol-gel spin coating technique. The surface structure, chemical components and transmittance spectra were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV-vis spectrophotometer. The TiO2 thin films with silver molar ratio from 0 to 10% were tested for its antibacterial property by using Escherichia coliform (E. coli) under irradiation of UV light. The concentration of E. coli was evaluated by plating technique. The influences of different molar ratio of Ag on hydrophilicity and long-term durability of the films were also investigated by measuring the water contact angle. The results showed that the antibacterial ability was significantly improved by increasing silver content comparing with pure TiO2 thin film, and the best molar ratio of Ag was 5%. While the hydrophilicity of films increased with increasing silver content, and the best molar ratio of Ag was 1%.

  17. Effect of electrode type in the resistive switching behaviour of TiO2 thin films

    International Nuclear Information System (INIS)

    The influence of the electrode/active layer on the electric-field-induced resistance-switching phenomena of TiO2-based metal-oxide-metal devices (MOM) is studied. TiO2 active layers were fabricated by the reactive rf-sputtering technique and devices were made by sandwiching between several metal electrodes. Three different MOM devices were made, according with the junction type formed between the electrode and the TiO2 active layer, those where Ohmic-Ohmic, Ohmic-Schottky and Schottky-Schottky. The junction type was tested by electrical I-V measurements. It was found that MOM devices made with the Ohmic-Ohmic combination did not show any resistive switching behaviour in contrast with devices made with Ohmic-Schottky and Schottky-Schottky combinations. From a detailed analysis of the I-V curves it was found that transport characteristics are Ohmic for the low-resistance state for all the contacts combinations of the MOM devices, whereas in the high-resistance state it depends on contact combinations and can be identified as Ohmic, Schottky and Poole-Frenkel type. These conduction mechanisms in the low- and high-resistance states suggest that formation and rupture of conducting filaments through the film oxide is the mechanism responsible for the resistance switching.

  18. Photocatalytic properties of dense plasma focus deposited nano phase TiO2 thin films: annealing effect

    International Nuclear Information System (INIS)

    Successful deposition of nano phase TiO2 thin films on silicon and glass substrates were achieved using the dense plasma focus (DPF) device. TiO2 thin films were prepared from a 99.95% pure titanium rod in oxygen–argon working gas mixture at ambient room temperature. The EDX and XPS results give the elemental composition of the films as Ti and O2. The XRD shows that amorphous films are predominant for low number of plasma focus shots. The SEM micrographs confirm the presence of nano-sized grains at smaller number of deposition shots or higher distance of deposition. Agglomeration was found to increase with the number of deposition shots. On annealing, the XRD diffractograms exhibit an increased in intensity and line width of the anatase (101) with the rutile phase R (110) emerging above 400°C. UV-Vis absorbance spectra for both as deposited and annealed films show a red shift for depositions from 20 plasma focus shots. The films showed visible light catalytic activity through decolouration of methylene blue solution. Visible light activity reached a maximum and decreased after 600 °C. Red shift and visible light catalysis can be explained in terms of the special feature effects of the plasma focus characteristic emissions. (author)

  19. Optical properties and switching durability of TiO2 top-coated magnesium–nickel thin-film switchable mirrors

    Science.gov (United States)

    Bao, Shanhu; Zhang, Xiaoli; Jin, Ping; Yoshimura, Kazuki

    2015-04-01

    An amorphous TiO2 film (180 nm) was deposited as a protective layer on the surface of a triple-layer thin-film switchable mirror (Pd/Ti/Mg4Ni deposited on glass) by a sol–gel coating process, and its optical switching behavior and switching lifetime under 4% hydrogen gas loading were evaluated. The use of a TiO2 coating extended the switching durability to about 1600 cycles, which is a fourfold increase compared with that of uncoated mirrors. The switching response of the Pd/Ti/Mg4Ni thin film was not affected by the presence of the TiO2 film, with hydrogenation and dehydrogenation speeds being almost the same as those of uncoated mirrors. The optical properties of the TiO2-coated mirrors were improved in the hydrogenated state, and a diffuse reflection phenomenon was observed in the dehydrogenated state.

  20. Fabrication and Characterization of Hydrophilic TiO2 Thin Films on Unheated Substrates Prepared by Pulsed DC Reactive Magnetron Sputtering

    International Nuclear Information System (INIS)

    TiO2 thin films were deposited on unheated silicon wafers (100) and glass slides by a pulsed DC reactive magnetron sputtering in an ultrahigh vacuum (UHV) system. The effects of both an operating pressure and deposition time on film structure, surface morphology, and optical property were studied. The film structure and microstructure were characterized by grazing-incidence X-ray diffraction (GIXRD) technique and transmission electron microscopy (TEM). The surface morphology was investigated by field emission scanning electron microscopy (FE-SEM). The optical property of the TiO2 thin films was determined by spectroscopic ellipsometry (SE). The water contact angle measurement was also used to determine hydrophilicity of the films after exposed to UV light. The results suggested that the TiO2 thin film at less than 40?nm was amorphous. As the thickness was increased, the mixture of anatase and rutile phases of TiO2 began to form. By reducing the operating pressure during the film deposition, the rutile phase component can also be enhanced. Both the increased film thickness and decrease operating pressure were the critical factors to improve the hydrophilicity of the TiO2 thin films.

  1. Fabrication and Characterization of Hydrophilic TiO2 Thin Films on Unheated Substrates Prepared by Pulsed DC Reactive Magnetron Sputtering

    Directory of Open Access Journals (Sweden)

    M. Horprathum

    2010-01-01

    Full Text Available TiO2 thin films were deposited on unheated silicon wafers (100 and glass slides by a pulsed DC reactive magnetron sputtering in an ultrahigh vacuum (UHV system. The effects of both an operating pressure and deposition time on film structure, surface morphology, and optical property were studied. The film structure and microstructure were characterized by grazing-incidence X-ray diffraction (GIXRD technique and transmission electron microscopy (TEM. The surface morphology was investigated by field emission scanning electron microscopy (FE-SEM. The optical property of the TiO2 thin films was determined by spectroscopic ellipsometry (SE. The water contact angle measurement was also used to determine hydrophilicity of the films after exposed to UV light. The results suggested that the TiO2 thin film at less than 40?nm was amorphous. As the thickness was increased, the mixture of anatase and rutile phases of TiO2 began to form. By reducing the operating pressure during the film deposition, the rutile phase component can also be enhanced. Both the increased film thickness and decrease operating pressure were the critical factors to improve the hydrophilicity of the TiO2 thin films.

  2. Spray pyrolysed microporous TiO2 thin films by optimisation of substrate temperature for ‘all sprayed’ solar cells

    Science.gov (United States)

    Santhosh, M. V.; Deepu, D. R.; Geethu, R.; Rajeev Kumar, K.; Sudha Kartha, C.; Vijayakumar, K. P.

    2014-11-01

    Titanium dioxide thin films were deposited on glass substrate at temperatures ranging from 300 °C to 500 °C by a simple, cost effective spray pyrolysis method using commercially available TiO2 powder (Degussa P25). Analyses using scanning electron microscopy (SEM) and atomic force microscopy (AFM) reveal the microporous nature of the films at 350 °C. X-ray diffraction (XRD) and Raman studies reveal that these films are amorphous in nature. The films were subsequently annealed at 500 °C for 2 h, resulting in crystallisation (the tetragonal anatase phase). XPS analysis was effectively used to study the chemical composition of the samples. Finally, optimized microporous TiO2 thin films were used for the fabrication of an ‘all-sprayed’ solar cell utilizing well-established CuInS2 as the absorber layer. The best device under this study has an open-circuit voltage of 409 mV and a short-circuit current density of 3.90 mA cm?2. The efficiency and fill factor were 0.61% and 38%, respectively.

  3. X-ray spectroscopic methods in the studies of nonstoichiometric TiO2?x thin films

    International Nuclear Information System (INIS)

    X-ray spectroscopic techniques have been used in the studies of electronic and structural properties of nonstoichiometric TiO2?x thin films obtained by reactive sputtering from Ti target. Films characterisation has been completed by means of X-ray diffraction in grazing incidence, GID, UV Raman and impedance spectroscopy, optical spectrophotometry, 1s3p Resonant X-ray Emission Spectroscopy, RXES, and X-ray Photoelectron Spectroscopy, XPS. Stoichiometric thin films of TiO2 are composed of a well-crystallised anatase–rutile mixture with the predominance of anatase while the films with higher oxygen deficit are amorphous to larger extent. Oxidation state changes from Ti4+ in stoichiometric films towards Ti3+ upon increasing departure from stoichiometric composition. This change is accompanied by the significant decrease in the electrical resistivity. The comparison of band gap energies, determined independently from optical and valence band X-ray absorption/emission spectra is good assuming direct allowed transitions.

  4. Oxidative degradation of industrial wastewater using spray deposited TiO2/Au:Fe2O3 bilayered thin films.

    Science.gov (United States)

    Mahadik, M A; Shinde, S S; Pathan, H M; Rajpure, K Y; Bhosale, C H

    2014-12-01

    The Fe2O3, Au:Fe2O3, TiO2/Fe2O3 and TiO2/Au:Fe2O3 thin films are successfully prepared by the spray pyrolysis technique at an optimised substrate temperature of 400 °C and 470 °C, respectively onto amorphous and F:SnO2 coated glass substrates. The effect of TiO2 layer onto photoelectrochemical (PEC), structural, optical and morphological properties of Fe2O3, Au:Fe2O3, TiO2/Fe2O3 and TiO2/Au:Fe2O3 thin films is studied. The PEC characterization shows that, maximum values of short circuit current (Isc) and open circuit voltage (Voc) are (Isc = 185 ?A and Voc = 450 mV) are at 38 nm thickness of TiO2. Deposited films are polycrystalline with a rhombohedral and anatase crystal structure having (104) preferred orientation. SEM and AFM images show deposited thin films are compact and uniform with seed like grains. The photocatalytic activities of the large surface area (64 cm(2)) TiO2/Au:Fe2O3 thin film photocatalysts were evaluated by photoelectrocatalytic degradation of industrial wastewater under sunlight light irradiation. The results show that the TiO2/Au:Fe2O3 thin film photocatalyst exhibited about 87% and 94% degradation of pollutant in sugarcane and textile industrial wastewater, respectively. The significant reduction in COD and BOD values from 95 mg/L to 13 mg/L and 75 mg/L to 11 mg/L, respectively was also observed. PMID:25463684

  5. Highly oriented and physical properties of sprayed anatase Sn-doped TiO2 thin films with an enhanced antibacterial activity

    Science.gov (United States)

    Dhanapandian, S.; Arunachalam, A.; Manoharan, C.

    2015-04-01

    Pristine TiO2 and Sn-doped TiO2 thin films with different Sn doping levels (2, 4, 6 and 8 at.%) were deposited by employing a simplified spray pyrolysis technique. The XRD pattern of the films confirmed tetragonal structure with the polycrystalline nature. The films exhibited a pure anatase titanium dioxide (TiO2) with a strong orientation along (101) plane. The scanning electron microscopy image of 6 at.% Sn-doped TiO2 thin film depicted nanosized grains with porous nature. The atomic force microscopy study had shown the columnar arrangement of grains with the increase in particle size and surface roughness for 6 at.% Sn-doped TiO2 thin films. The optical transmittance was increased with the decrease in the optical energy band gap. The optical constants such as extinction coefficient and refractive index were determined. The intensity of the photoluminescence emission was observed at 398 nm for doped films. The resistivity decreased with the increasing carrier concentration and Hall mobility. The incorporation of Sn into TiO2 matrix yielded a well-pronounced antibacterial activity for Bacillus subtilis.

  6. Apatite formation from simulated body fluid on various phases of TiO2 thin films prepared by filtered cathodic vacuum arc deposition

    International Nuclear Information System (INIS)

    Hydroxyl (OH-)-free TiO2 thin films with amorphous and crystalline phases were deposited onto (100) silicon substrates using filtered cathodic vacuum arc deposition in order to investigate the in vitro apatite formation in simulated body fluid (SBF). The surface morphology, composition and structure of the TiO2 thin films were characterized. The X-ray photoelectron spectroscopy results confirmed the presence of calcium and phosphorus on all TiO2 thin film surfaces after immersion in SBF at 37 oC. Fourier transform infra red results showed the presence of carbonated apatite on the surface of these films. Amorphous structured TiO2 thin film showed poor ability to form apatite on its surface in SBF. Apatite formation was more pronounced on the surfaces of the anatase films in comparison to those of rutile. The carbonated apatite deposition rate increased significantly when the TiO2 film was illuminated with UV light prior to immersing in the SBF. In particular, the UV-treated anatase and rutile films showed increased rates of carbonated apatite formation on their surfaces in comparison to samples not treated with radiation. The increase in hydrophilicity due to UV treatment appears beneficial for the apatite growth on these surfaces.

  7. Thickness-dependent electron transport performance of mesoporous TiO2 thin film for dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Anatase titania (TiO2) nanocrystals with an average size of 12 nm were synthesized by combining sol–gel method and hydrothermal crystallization technology. Mesoporous TiO2 thin film electrodes (MTTFEs) were prepared by variations in layer of screen-printed TiO2 nanocrystals pastes, and dye-sensitized solar cells (DSCs) based on different thickness of MTTFEs were fabricated with dye C106. Under the irradiation of 100 mW cm?2 air mass 1.5 global (AM1.5G) sunlight, the short-circuit photocurrent density (Jsc) and overall conversion efficiency (?) was improved when the thickness of MTTFEs increased from 2.1 ?m to 9.8 ?m, and obvious decreases of the Jsc and ? were found when the film thickness was further increased over 9.8 ?m. The kinetic parameters of electron transport were investigated by the transient photoelectrical and electrical impedance measurements, and then the influence of MTTFEs thickness on electron transport performance in DSCs were further discussed. The results showed that the density of states (DOS) and recombination rate (Kr) increased with the MTTFEs thickness increasing. Furthermore, when the thickness of MTTFEs was in the range of 2.1–9.8 ?m, the electron lifetime (?n), the electron diffusion coefficient (Dn), and the electron diffusion length (Ln) of devices increased, but these parameters decreased gradually with the further increased thickness of MTTFEs, which influenced the electronic transport performance of DSCs

  8. Synthesis of TiO2 thin films using single molecular precursors by MOCVD method for dye-sensitized solar cells application and study on film growth mechanism

    International Nuclear Information System (INIS)

    For dye-sensitized solar cells application, in this study, we have synthesized TiO2 thin films at deposition temperature in the range of 300–750 °C by metalorganic chemical vapor deposition (MOCVD) method. Titanium(IV) isopropoxide, (TIP, Ti(OiPr)4) and Bis(dimethylamido)titanium diisopropoxide, (BTDIP, (Me2N)2Ti(OiPr)2) were used as single source precursors that contain Ti and O atoms in the same molecule, respectively. Crack-free, highly oriented TiO2 polycrystalline thin films with anatase phase were deposited on Si(1 0 0) with TIP at temperature as low as 450 °C. XRD and TED data showed that below 500 °C, the TiO2 thin films were dominantly grown in the [2 1 1] direction on Si(1 0 0), whereas with increasing the deposition temperature to 700 °C, the main film growth direction was changed to [2 0 0]. Above 700 °C, however, rutile phase TiO2 thin films have only been obtained. In the case of BTDIP, on the other hand, only amorphous film was grown on Si(1 0 0) below 450 °C while a highly oriented anatase TiO2 film in the [2 0 0] direction was obtained at 500 °C. With further increasing deposition temperatures over 600 °C, the main film growth direction shows a sequential change from rutile [1 0 1] to rutile [4 0 0], indicating a possibility of getting single crystalline TiO2 film with rutile phase. This means that the precursor together with deposition temperature can be one of important parameters to influence film growth direction, crystallinity as well as crystal structure. To investigate the CVD mechanism of both precursors in detail, temperature dependence of growth rate was also carried out, and we then obtained different activation energy of deposition to be 77.9 and 55.4 kJ/mol for TIP and BTDIP, respectively. Also, we are tested some TiO2 film synthesized with BTDIP precursor to apply dye-sensitized solar cell.

  9. Cobalt valence states and origins of ferromagnetism in Co doped TiO2 rutile thin films

    International Nuclear Information System (INIS)

    Co doped rutile thin films were fabricated on ?-Al2O3 (10-12) substrates by laser molecular beam epitaxy. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy indicated that the rutile thin films are (101) oriented and have smooth surfaces with no impurity phases. Co K-edge x-ray absorption near-edge structure, extended x-ray absorption fine structure, and x-ray photoelectron spectroscopy revealed the coexistence of different valence states of Co in the film. Magnetic circular dichroism studies suggest that the observed ferromagnetism is uniform and is related to the electron band structure of TiO2 rutile. Contribution of oxidized (Co2+) and metallic (Co0) cobalt to the ferromagnetism is discussed

  10. Nanostructured nitrogen and carbon codoped TiO2 thin films: Synthesis, structural characterization and optoelectronic properties

    Science.gov (United States)

    Ruzybayev, Inci

    TiO2 is widely used in applications like photocatalysis, sensors, solar cells, and memory devices because it is inexpensive, abundant, nontoxic and stable in aqueous solution. Another exciting application where TiO 2 has the potential to be a very useful catalyst is the clean hydrogen generation using solar radiation. Energy consumption is increasing every year and, as a result, renewable and sustainable alternative energy sources are becoming increasingly important. Therefore, clean hydrogen generation research is becoming more and more important. This study aims at the preparation and characterization of nitrogen and carbon (N-C) codoped TiO2 photoanode material that could potentially be used in photoelectrochemical cells for hydrogen generation. The solar spectrum peaks around 500 nm (2.48 eV) which is in the visible part of the spectrum. The photoanode material to be used for solar hydrogen generation should absorb visible light photons to yield high efficiency. The challenge with TiO2 is that the wide band gap (3.00--3.20 eV) absorbs only ultra-violet (UV) photons and only a small percentage of the solar spectrum is in the UV range. There are various ways to overcome the challenge of sensitizing the material to visible light absorption and this study focuses on one of the most promising ways: band modification of TiO2 by N-C codoping. The role of pure oxygen pressure on pulsed laser deposited N-C codoped TiO2 films were investigated. At low pressures rutile phase of TiO2 was dominant and a microstructure with densely packed grains was obtained. However, at high pressures anatase phase became dominant and columnar structure was favored. Therefore, the anatase-rutile phase ratio as well as the microstructure of the films can be controlled by adjusting oxygen pressure and introducing N and C into the TiO2 matrix. Optimized oxygen pressure and higher doping concentrations yielded films with more effective absorption in the visible region. The preparation and characterization of pulsed laser deposited N-C codoped TiO2 thin films were investigated for dopant incorporation using N2 and CH4 gases. Polycrystalline anatase structured films were obtained. A 2 theta shift of the anatase (101) X-ray diffraction main peak towards lower values indicated carbon incorporation into the lattice. N incorporation was confirmed with observed Ti-N bonds using X-ray photoelectron spectroscopy. Optical data showed significant reduction, approximately 1.00 eV, of the band gap. The reduction of the band gap allowed the photons in the visible part of the solar spectrum to be absorbed. Through a collaborative work with scientists at Brookhaven National Laboratory and Yonsei University, precise modeling of the electronic structure of N-C codoped TiO2 films were carried out to reveal the underlying physics of band gap reduction. Experimental results were compared with first-principle density functional theory calculations. Hard X-ray photoelectron spectroscopy showed that O, N and C 2p states overlapped effectively and shifts in the valence band maximum towards the Fermi level were observed. Optical band gap results showed that N-C codoping is an effective route for band gap reduction in TiO2. Comparison of the measured valence band structure with theoretical photoemission density of states further revealed C substitution on the Ti site and N substitution on the O site. Finally, films grown using radio frequency (rf) magnetron sputtering were compared with the pulsed laser deposited films. Sputtered N-C codoped TiO2 films showed phase transformation from anatase to rutile at constant argon pressure with increasing doping concentration. Moreover, with slow-rate N-C codoping of TiO2, a texturing effect was observed in X-ray diffraction scans such that anatase (004) Bragg reflection plane became more favored over anatase (101). Optical band gap was reduced but the reduction was not as significant as in the films prepared with the pulsed laser deposition method. Electrochemical methods were applied in the photoelectrochemical cell and the sample prep

  11. The Influence of Various Deposition Techniques on the Structural and Photoelectrochemical Properties of the thin TiO2 Films.

    Czech Academy of Sciences Publication Activity Database

    Morozová, Magdalena; Kluso?, Petr; Dzik, P.; Veselý, M.; Baudys, M.; Krýsa, J.; Šolcová, Olga

    Prague : KANAG -TISK, 2014 - (Krýsa, J.; Kluso?, P.), s. 14-15 ISBN 978-80-7080-886-3. [Czech-Austrian Workshop: New Trends in Photo and Electro Catalysis /6./. Hnanice (CZ), 02.12.2013-04.12.2013] R&D Projects: GA TA ?R TA01020804 Grant ostatní: GA ?R(CZ) GP104/09/P165; GA ?R(CZ) GAP108/12/2104 Institutional support: RVO:67985858 Keywords : thin films * nanostructured electrode material * TiO2 layers Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  12. Irradiation induced ferromagnetism at room temperature in TiO2 thin films: X-ray magnetic circular dichroism characterizations

    International Nuclear Information System (INIS)

    We report on the room temperature ferromagnetism in the swift heavy ion (SHI) irradiated TiO2 thin films by x-ray absorption spectroscopy (XAS) and x-ray magnetic circular dichroism (XMCD) experiments at the O K and Ti L3,2 absorption edges. The XAS/XMCD measurements provide direct evidence of magnetic polarization of the O 2p and Ti 3d orbitals. The unquenched orbital magnetic moment within the O 2p shell is ferromagnetically coupled to the neighboring Ti moments, which illustrates the intense hybridization of the O 2p and Ti 3d orbitals induced by SHI irradiation.

  13. Photocatalytic activity of Al2O3-doped TiO2 thin films activated with visible light on the bacteria Escherichia coli

    International Nuclear Information System (INIS)

    Al2O3-doped TiO2 thin films were prepared by combining electrophoretic deposition (EPD) with sputtering. A Corning* glass was used as a substrate, in which a titanium film was deposited by sputtering. Then, a precursor sol was prepared with Ti(n-OBu)4 and Al(s-OBu)3 and used as the medium for EPD. Next, the thin films were sintered and, finally, characterised by scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). Several cultures of Escherichia coli, strain XL1-Blue, were prepared. Nine experiments were carried out. In three of them, an inoculum (a low amount of a product that contains bacteria) was prepared without a film; in the other six Al2O3-doped TiO2 film-coated glass substrates were irradiated with visible light before they were introduced in the inoculum. The SEM and EDS results showed that TiO2-Al2O3 films were obtained, covering all the glass substrate and with uniform size of particles forming them, and that the aluminium was distributed uniformly on the film. XRD results showed that rutile phase was obtained. By TEM, the structure of TiO2 was demonstrated. Al2O3-doped TiO2 thin films were successful at eliminating E. coli.

  14. The role of energetic ion bombardment during growth of TiO2 thin films by reactive sputtering

    International Nuclear Information System (INIS)

    TiO2 thin films have been deposited by several different sputtering processes: (i) dc magnetron sputtering (dcMS) employing various geometrical conditions, (ii) ion-assisted dc magnetron sputtering where additional ion bombardment of the growing films was performed with an auxiliary ECR ion source and (iii) high power impulse magnetron sputtering (HiPIMS). Films have been investigated mainly by grazing incidence x-ray diffraction and atomic force microscopy. It is shown that the highly energetic oxygen ions inherent in reactive sputtering of metal oxides are the dominant energetic species governing structure formation of TiO2 films by their kinetic impact. The trajectories of these energetic oxygen ions strongly depend on the shape of the erosion trace and hence on the age of the target, which therefore has a strong influence on structure formation. Furthermore, in a HiPIMS discharge the role of this energetic oxygen ion bombardment is strongly intensified due to the increased target voltage and the lower deposition rate compared with a dcMS discharge. It is also demonstrated that films with pure rutile structure which are stable under a post-deposition thermal treatment can be deposited under intense energetic ion bombardment at low temperatures either by HiPIMS at high peak power densities or by ion-assisted dcMS.

  15. Strategies to prepare TiO2 thin films, doped with transition metal ions, that exhibit specific physicochemical properties to support osteoblast cell adhesion and proliferation

    International Nuclear Information System (INIS)

    Metal ion doped titanium oxide (TiO2) thin films, as bioactive coatings on metal or other implantable materials, can be used as surfaces for studying the cell biological properties of osteogenic and other cell types. Bulk crystallite phase distribution and surface carbon–oxygen constitution of thin films, play an important role in determining the biological responses of cells that come in their contact. Here we present a strategy to control the polarity of atomic interactions between the dopant metal and TiO2 molecules and obtain surfaces with smaller crystallite phases and optimal surface carbon–oxygen composition to support the maximum proliferation and adhesion of osteoblast cells. Our results suggest that surfaces, in which atomic interactions between the dopant metals and TiO2 were less polar, could support better adhesion, spreading and proliferation of cells. - Highlights: • Electrochemical properties of dopants control the nature of TiO2 thin films. • A model explains the correlation of dopant properties and behaviour of TiO2 films. • Dopants with less polar interaction with TiO2 exhibit better biological activity

  16. Growth and characterization of nitrogen-doped TiO2 thin films prepared by reactive pulsed laser deposition

    International Nuclear Information System (INIS)

    Nitrogen-doped titanium dioxide (TiO2) thin films were grown on (001) SiO2 substrates by reactive pulsed laser deposition. A KrF* excimer laser source (? = 248 nm, ?FWHM ? 10 ns, ? = 10 Hz) was used for the irradiations of pressed powder targets composed by both anatase and rutile phase TiO2. The experiments were performed in a controlled reactive atmosphere consisting of oxygen or mixtures of oxygen and nitrogen gases. The obtained thin film crystal structure was investigated by X-ray diffraction, while their chemical composition as well as chemical bonding states between the elements were studied by X-ray photoelectron spectroscopy. An interrelation was found between nitrogen concentration, crystalline structure, bonding states between the elements, and the formation of titanium oxinitride compounds. Moreover, as a result of the nitrogen incorporation in the films a continuous red-shift of the optical absorption edge accompanied by absorption in the visible spectral range between 400 and 500 nm wavelength was observed.

  17. Al2O3/TiO2 nanolaminate thin film encapsulation for organic thin film transistors via plasma-enhanced atomic layer deposition.

    Science.gov (United States)

    Kim, Lae Ho; Kim, Kyunghun; Park, Seonuk; Jeong, Yong Jin; Kim, Haekyoung; Chung, Dae Sung; Kim, Se Hyun; Park, Chan Eon

    2014-05-14

    Organic electronic devices require a passivation layer that protects the active layers from moisture and oxygen because most organic materials are very sensitive to such gases. Passivation films for the encapsulation of organic electronic devices need excellent stability and mechanical properties. Although Al2O3 films obtained with plasma enhanced atomic layer deposition (PEALD) have been tested as passivation layers because of their excellent gas barrier properties, amorphous Al2O3 films are significantly corroded by water. In this study, we examined the deformation of PEALD Al2O3 films when immersed in water and attempted to fabricate a corrosion-resistant passivation film by using a PEALD-based Al2O3/TiO2 nanolamination (NL) technique. Our Al2O3/TiO2 NL films were found to exhibit excellent water anticorrosion and low gas permeation and require only low-temperature processing (<100 °C). Organic thin film transistors with excellent air-stability (52 days under high humidity (a relative humidity of 90% and a temperature of 38 °C)) were fabricated. PMID:24712401

  18. Optical properties of nanogranular and highly porous TiO2 thin films

    International Nuclear Information System (INIS)

    We present a systematic investigation of the optical properties of cluster-assembled TiO2 films (20–150 nm nominal thickness) deposited onto Si wafers and processed with two types of ex-situ oxidation treatments. Spectroscopic ellipsometry (0.7–5 eV energy range), supported by x-ray photoelectron spectroscopy and atomic force microscopy measurements, allowed us to obtain information on the depth-dependent morphology of the films in a non-destructive mode. The characteristic grainy and porous structure of the films was modelled by means of a flexible effective-medium approach, allowing us to obtain a reliable estimate of the amount and distribution of voids into the films and their accessibility to foreign liquids. The absorption-edge broadening and significant optical absorptions within the gap were attributed to the intrinsically nanogranular morphology and to the interrelated defective structure/stoichiometry of the particles, also in relation to the occurrence of poorly accessible interstices or pores in the inner parts of the film. (paper)

  19. Interfacial band alignment and structural properties of nanoscale TiO2 thin films for integration with epitaxial crystallographic oriented germanium

    International Nuclear Information System (INIS)

    We have investigated the structural and band alignment properties of nanoscale titanium dioxide (TiO2) thin films deposited on epitaxial crystallographic oriented Ge layers grown on (100), (110), and (111)A GaAs substrates by molecular beam epitaxy. The TiO2 thin films deposited at low temperature by physical vapor deposition were found to be amorphous in nature, and high-resolution transmission electron microscopy confirmed a sharp heterointerface between the TiO2 thin film and the epitaxially grown Ge with no traceable interfacial layer. A comprehensive assessment on the effect of substrate orientation on the band alignment at the TiO2/Ge heterointerface is presented by utilizing x-ray photoelectron spectroscopy and spectroscopic ellipsometry. A band-gap of 3.33?±?0.02?eV was determined for the amorphous TiO2 thin film from the Tauc plot. Irrespective of the crystallographic orientation of the epitaxial Ge layer, a sufficient valence band-offset of greater than 2?eV was obtained at the TiO2/Ge heterointerface while the corresponding conduction band-offsets for the aforementioned TiO2/Ge system were found to be smaller than 1?eV. A comparative assessment on the effect of Ge substrate orientation revealed a valence band-offset relation of ?EV(100)?>??EV(111)?>??EV(110) and a conduction band-offset relation of ?EC(110) >??EC(111)?>??EC(100). These band-offset parameters are of critical importance and will provide key insight for the design and performance analysis of TiO2 for potential high-? dielectric integration and for future metal-insulator-semiconductor contact applications with next generation of Ge based metal-oxide field-effect transistors

  20. Photocatalytically active TiO2 thin films produced by surfactant-assisted sol-gel processing

    International Nuclear Information System (INIS)

    Thin TiO2 films were prepared from a titanium isopropoxide precursor by sol-gel processing with or without various nonionic surfactant molecules (Brij 56, Triton X-100 or Pluronic F-127). The photocatalytic efficiency of the transparent films obtained by a dip-coating technique was found to depend strongly on the use of and type of surfactant added. Titania/Pluronic sols resulted in homogeneous and crack-free TiO2 anatase films with a thickness as much as 300 nm after one dipping and heat-treatment (500 deg. C) cycle. Optical properties of the films were characterized by UV-Vis spectroscopy and crystalline structures by X-ray diffraction. A surfactant-assisted sol-gel process retarded crystallization of the anatase titania films, which resulted in smaller grain sizes (down to 10 nm) and presumably a larger active surface area. The morphology of the film surfaces as obtained by SEM techniques could be also correlated with the results of our photodegradation studies. The photocatalytic activity of the films was enhanced by first coating the glass substrate with a SiO2 protective layer prior to the deposition of the titania film. For our in situ studies of photodegradation we chose the monoazo dye Plasmocorinth B as a model compound as it is stable under environmental conditions and its degradation products are not coloured. The highest photobleaching rate was found for films deposited from the sol with addition of the Pluronic surfactantl with addition of the Pluronic surfactant and it was almost twice as high as that for films deposited from sols without the surfactant

  1. Polaron variable range hopping in TiO2-?(-0.04=thin films

    International Nuclear Information System (INIS)

    The mechanisms of electrical conduction in TiO2-?(-0.04=2+Ar gas atmospheres where changes in ? and film structure had been achieved by varying the O2 flow rate and the substrate temperature. The electrical transport properties of these samples were investigated by measuring the conductivity as a function of temperature between 17K and room temperature. At the temperature range between 200 and 290K the best fit to the experimental data was obtained assuming a dependence characteristic of adiabatic variable range hopping. At lower temperature the activation energy for the conductivity tends to zero. The results suggest that the conduction mechanism is adiabatic small polaron hopping, which switches to conduction in a polaron band at low temperatures

  2. TiO2(Fe3+) nanostructured thin films with antibacterial properties

    International Nuclear Information System (INIS)

    TiO2-based nanostructured Fe3+-doped coatings have been prepared by the sol-gel method on glass substrates. The coatings were characterized by X-ray diffraction and spectroellipsometry methods. The influence of Fe3+ dopant concentration, number of coatings, and calcination temperature on the films structure was established. The antibacterial activity against E. coli, has been studied applying the so-called antibacterial-drop test. The bactericidal activity for the above bacteria cells was estimated by relative number of bacteria survived calculated from the number of viable cells which form colonies on the nutrient agar plates. The coatings exhibited a high antibacterial activity, which was enhanced with the increase of the temperature of thermal treatment and formation of anatase crystalline structure. The long thermal treatment results in rutile crystalline structure formation followed by the decrease in the antibacterial activity of the coating

  3. Control of crystallographic texture and surface morphology of Pt/Tio2 templates for enhanced PZT thin film texture.

    Science.gov (United States)

    Fox, Austin J; Drawl, Bill; Fox, Glen R; Gibbons, Brady J; Trolier-McKinstry, Susan

    2015-01-01

    Optimized processing conditions for Pt/TiO2/SiO2/Si templating electrodes were investigated. These electrodes are used to obtain [111] textured thin film lead zirconate titanate (Pb[ZrxTi1-x ]O3 0 ? x ? 1) (PZT). Titanium deposited by dc magnetron sputtering yields [0001] texture on a thermally oxidized Si wafer. It was found that by optimizing deposition time, pressure, power, and the chamber pre-conditioning, the Ti texture could be maximized while maintaining low surface roughness. When oxidized, titanium yields [100]-oriented rutile. This seed layer has as low as a 4.6% lattice mismatch with [111] Pt; thus, it is possible to achieve strongly oriented [111] Pt. The quality of the orientation and surface roughness of the TiO2 and the Ti directly affect the achievable Pt texture and surface morphology. A transition between optimal crystallographic texture and the smoothest templating surface occurs at approximately 30 nm of original Ti thickness (45 nm TiO2). This corresponds to 0.5 nm (2 nm for TiO2) rms roughness as determined by atomic force microscopy and a full-width at half-maximum (FWHM) of the rocking curve 0002 (200) peak of 5.5/spl degrees/ (3.1/spl degrees/ for TiO2). A Pb[Zr0.52Ti 0.48]O3 layer was deposited and shown to template from the textured Pt electrode, with a maximum [111] Lotgering factor of 87% and a minimum 111 FWHM of 2.4/spl degrees/ at approximately 30 nm of original Ti. PMID:25585390

  4. Nanocrystalline anatase TiO2 thin films: preparation and crystallite size-dependent properties

    International Nuclear Information System (INIS)

    Nanocrystalline anatase TiO2 films with crystallites of either of three different sizes (nominally 6, 12, and 20 nm) were deposited on various substrates (glass, sapphire, and silicon) using colloidal suspensions. These suspensions were painted onto the respective substrates, dried in air and then calcined at 720 K in air for 1 h; the resulting films have a whitish appearance and are several ?m thick. These films were thoroughly characterized with respect to their surface morphology, crystal structure, phase homogeneity, elemental composition, and the presence of impurities. X-ray diffraction (XRD) and cross-section transmission electron microscopy (TEM) data demonstrated that two of the films are solely composed of the anatase phase whereas in the third also the brookite phase of TiO2 might be present. The average crystallite size was derived from the width of the XRD diffraction peaks and was found to agree within ?5% with the nominal size. The elemental composition and the amount of impurities in the different films was investigated by secondary-ion mass spectrometry. Whereas the Ti/O concentration is constant throughout all films, the presence of contaminants is substrate-dependent: while in films deposited on silicon or sapphire the atomic fraction of impurities (most prominently Na and K) is in the range of ?10-4, for glass substrates an about 100 times higher level of those species is observed, probably the result of outdifserved, probably the result of outdiffusion during the calcination step or during the reduction of the samples. A detailed study of the influence of the sample temperature T and the ambient oxygen pressure p(O2) on the DC electrical conductivity ? of the films was performed. For all films, a power-law dependence of ? on p(O2), ??p(O2)-n, was observed. The values of the exponent n were found to exhibit a distinct dependence both on the crystallite size and on the specimen temperature; furthermore, an influence due to the presence of doping species was noted. For nanocrystalline films on sapphire substrates and for T=470 K, n amounts to 1.31, 1.15 and 0.56 for the 6-, 12-, and 20-nm films, respectively. For reduced films, an exponential dependence of ? on T -1 was determined, yielding activation energies EA with values of 0.34, 0.38, and 0.51 eV for films with those crystallite sizes. Impedance spectroscopy was utilized to determine the frequency-dependent complex resistance of the various films. In all cases, a pure RC behavior was found: whereas the magnitude of R strongly depends on the crystallite size, the sample temperature and the ambient oxygen pressure, C exhibits little variations and falls in the range ?18 to ?25 pF. Using thermal desorption mass spectrometry, distinct desorption peaks for O2 species were observed which shift to higher temperature values with increasing heating rate. An activation energy for that desorption process of ?0.9 eV was obtained thereof for a 6-nm nanocrystalline film

  5. Room temperature synthesis of nanocrystalline anatase sols and preparation of uniform nanostructured TiO2 thin films: optical and structural properties

    Science.gov (United States)

    Hosseingholi, M.; Pazouki, M.; Hosseinnia, A.; Aboutalebi, S. H.

    2011-02-01

    Transparent TiO2 thin films were deposited on soda-lime glass substrates via the sol-gel method using a nanocrystalline TiO2 sol solution prepared at room temperature employing the dip-coating method. The effects of pH on crystallinity, particle size and stability of the synthesized TiO2 sols were investigated, systematically. TiO2 thin films were thickened by means of a sequential dip-coating process. The TiO2 films were transparent and exhibited proper adherence. The effects of thickness and annealing temperature on the structural and optical properties of the thin films were evaluated. The prepared powder was crystalline without any thermal treatment. The crystallite size of the particles (anatase) was in the range 4.2-12.1 nm depending on the initial pH value. Although only the anatase phase was observed at room temperature and 400 °C, a further increase in annealing temperature up to 700 °C resulted in the formation of the rutile phase. Even at high annealing temperatures, fairly smooth and homogeneous surfaces with no cracks and pores were observed. It was demonstrated that the films were transparent in the visible region with characteristic absorption in the UV region. Band gap of the as-deposited film was estimated to be 3.34 eV and was found to decrease with increasing annealing temperature.

  6. Room temperature synthesis of nanocrystalline anatase sols and preparation of uniform nanostructured TiO2 thin films: optical and structural properties

    International Nuclear Information System (INIS)

    Transparent TiO2 thin films were deposited on soda-lime glass substrates via the sol-gel method using a nanocrystalline TiO2 sol solution prepared at room temperature employing the dip-coating method. The effects of pH on crystallinity, particle size and stability of the synthesized TiO2 sols were investigated, systematically. TiO2 thin films were thickened by means of a sequential dip-coating process. The TiO2 films were transparent and exhibited proper adherence. The effects of thickness and annealing temperature on the structural and optical properties of the thin films were evaluated. The prepared powder was crystalline without any thermal treatment. The crystallite size of the particles (anatase) was in the range 4.2-12.1 nm depending on the initial pH value. Although only the anatase phase was observed at room temperature and 400 deg. C, a further increase in annealing temperature up to 700 deg. C resulted in the formation of the rutile phase. Even at high annealing temperatures, fairly smooth and homogeneous surfaces with no cracks and pores were observed. It was demonstrated that the films were transparent in the visible region with characteristic absorption in the UV region. Band gap of the as-deposited film was estimated to be 3.34 eV and was found to decrease with increasing annealing temperature.

  7. Determination of the melting threshold of TiO2 thin films processed by excimer laser irradiation

    International Nuclear Information System (INIS)

    Processing surfaces by laser needs an understanding of the mechanisms generated by irradiation. In this work, to gain understanding of the mechanisms occurring during irradiation of TiO2 thin films by means of KrF excimer laser, we have performed infrared time resolved reflectivity measurements. This experimental investigation revealed modifications of the heating/cooling cycle as a function of the fluence (F). These modifications start appearing for a fluence value of about ?0.25 J/cm2 which is associated with the melting threshold of the film. Additionally, we have solved numerically the heat equation of the system with specific boundary conditions. From these calculations, we have established the thermal history of the film during the 25 ns irradiation pulse. The data reveal that a part of the medium liquefies around a fluence of 0.23 J/cm2 in good agreement with the experimental data.

  8. Structural and electrical characteristics of ZrO2-TiO2 thin films by sol-gel method

    International Nuclear Information System (INIS)

    In this paper, we investigated electrical properties and microstructures of ZrTiO4 (ZrO2-TiO2) thin films prepared by the sol-gel method on ITO substrates at different annealing temperatures. All films exhibited ZrTiO4 (1 1 1) and (1 0 1) orientations perpendicular to the substrate surface, and the grain size increased with increase in the annealing temperature. A low leakage current density of 2.06 x 10-6 A/cm2 was obtained for the prepared films. Considering the primary memory switching behavior of ZrTiO4, ReRAM based on ZrTiO4 shows promise for future nonvolatile memory applications.

  9. Superhydrophobic ceramic coatings enabled by phase-separated nanostructured composite TiO2-Cu2O thin films

    Science.gov (United States)

    Aytug, Tolga; Bogorin, Daniela F.; Paranthaman, Parans M.; Mathis, John E.; Simpson, John T.; Christen, David K.

    2014-06-01

    By exploiting phase-separation in oxide materials, we present a simple and potentially low-cost approach to create exceptional superhydrophobicity in thin-film based coatings. By selecting the TiO2-Cu2O system and depositing through magnetron sputtering onto single crystal and metal templates, we demonstrate growth of nanostructured, chemically phase-segregated composite films. These coatings, after appropriate chemical surface modification, demonstrate a robust, non-wetting Cassie-Baxter state and yield an exceptional superhydrophobic performance, with water droplet contact angles reaching to ˜172° and sliding angles coated composite film surfaces display UV stability and retain superhydrophobic attributes even after exposure to UV (275 nm) radiation for an extended period of time. The present approach could benefit a variety of outdoor applications of superhydrophobic coatings, especially for those where exposure to extreme atmospheric conditions is required.

  10. Ab-initio calculations of the Optical band-gap of TiO2 thin films

    CERN Document Server

    Wunderlich, W; Tanemura, M; Tanemura, S; Jin, P; Kaneko, K; Terai, A; Nabatova-Gabin, N; Belkada, R; Wunderlich, Wilfried; Miao, Lei; Tanemura, Masaki; Tanemura, Sakae; Jin, Ping; Kaneko, Kenji; Terai, Asuka; Nabatova-Gabin, Nataliya; Belkada, Rachid

    2004-01-01

    Titanium dioxide has been extensively studied in recent decades for its important photocatalytic application in environmental purification. The search for a method to narrow the optical band-gap of TiO2 plays a key role for enhancing its photocatalytic application. The optical band gap of epitaxial rutile and anatase TiO2 thin films deposited by helicon magnetron sputtering on sapphire and on SrTiO3 substrates was correlated to the lattice constants estimated from HRTEM images and SAED. The optical band-gap of 3.03 eV for bulk-rutile increased for the thin films to 3.37 on sapphire. The band gap of 3.20 eV for bulk-anatase increases to 3.51 on SrTiO3. In order to interpret the optical band gap expansion for both phases, ab-initio calculations were performed using the Vienna ab-initio software. The calculations for rutile as well anatase show an almost linear increase of the band gap width with decreasing volume or increasing lattice constant a. The calculated band gap fits well with the experimental values. T...

  11. Enhanced photoelectrochemical properties of F-containing TiO2 sphere thin film induced by its novel hierarchical structure

    International Nuclear Information System (INIS)

    The novel nanostructured F-containing TiO2 (F-TiO2) sphere was directly synthesized on the surface of Ti foil in the solution of NH4F and HCl by one-step hydrothermal approach under low-temperature condition. The samples were characterized respectively by means of field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results showed that the F-TiO2 sphere was hierarchical structure, which composed of porous octahedron crystals with one truncated cone, leading to a football-like morphology. XPS results indicated that F- anions were just physically adsorbed on the surface of TiO2 microspheres. The studies on the optical properties of the F-TiO2 were carried out by UV-vis light absorption spectrum. The surface fluorination of the spheres, the unique nanostructure induced accessible macropores or mesopores, and the increased light-harvesting abilities were crucial for the high photoelectrochemical activity of the synthesized F-TiO2 sphere for water-splitting. The photocurrent density of the F-TiO2 sphere thin film was more than two times than that of the P25 thin film. Meanwhile, a formation mechanism was briefly proposed. This approach could provide a facile method to synthesize F-TiO2 microsphere with a special morphology and hierarchical structure in lmorphology and hierarchical structure in large scale.

  12. A Micro Oxygen Sensor Based on a Nano Sol-Gel TiO2 Thin Film

    Directory of Open Access Journals (Sweden)

    Hairong Wang

    2014-09-01

    Full Text Available An oxygen gas microsensor based on nanostructured sol-gel TiO2 thin films with a buried Pd layer was developed on a silicon substrate. The nanostructured titania thin films for O2 sensors were prepared by the sol-gel process and became anatase after heat treatment. A sandwich TiO2 square board with an area of 350 ?m × 350 ?m was defined by both wet etching and dry etching processes and the wet one was applied in the final process due to its advantages of easy control for the final structure. A pair of 150 nm Pt micro interdigitated electrodes with 50 nm Ti buffer layer was fabricated on the board by a lift-off process. The sensor chip was tested in a furnace with changing the O2 concentration from 1.0% to 20% by monitoring its electrical resistance. Results showed that after several testing cycles the sensor’s output becomes stable, and its sensitivity is 0.054 with deviation 2.65 × 10?4 and hysteresis is 8.5%. Due to its simple fabrication process, the sensor has potential for application in environmental monitoring, where lower power consumption and small size are required.

  13. Synthesis and characterization of beta barium borate thin films obtained from the BaO-B2O3-TiO2 ternary system

    International Nuclear Information System (INIS)

    This work reports on the synthesis and the structural and optical characterization of beta barium borate (?-BBO) thin films containing 4, 8 and 16 mol% of titanium oxide (TiO2) deposited on fused silica and silicon (0 0 1) substrates using the polymeric precursor method. The thin films were characterized by X-ray diffraction, Raman spectroscopy, atomic force microscopy and scanning electron microscopy techniques. The optical transmission spectra of the thin films were measured over a wavelength range of 800-200 nm. A decrease was observed in the band gap energy as the TiO2 content was raised to 16 mol%. Only the ?-BBO phase with a preferential orientation in the (0 0 l) direction was obtained in the sample containing 4 mol% of TiO2 and crystallized at 650 deg. C for 2 h

  14. Polymer-assisted conformal coating of TiO2 thin films

    Science.gov (United States)

    Gillman, E. S.; Costello, D.; Moreno, M.; Raspopin, A.; Kasica, R.; Chen, L.

    2010-08-01

    Conformal coating of nanofabricated structures with a high-index dielectric material is a common problem for a diverse set of integrated photonic and plasmonic devices such as planar waveguides, on-chip spectrometers, gratings, flat panel displays, optical sensors, and integrated optical devices. In this paper we were recently able to demonstrate an alternate method for conformally coating photonic nanostructures using a low cost, polymer-assisted deposition (PAD) process for the metal-oxide TiO2. In a PAD process a thermally curable, hybrid high refractive index polymer solution is spin-coated onto a substrate. The polymer controls the viscosity and binds the metal ions, resulting in a homogeneous distribution of the precursor in solution. When cured at elevated temperature, the hybrid polymer coating decomposes to form a metal oxide-rich film that has a high refractive index that conformally fills the voids in nanofabricated structures. The resulting films have refractive indices higher than 1.83 in the visible region and film thicknesses between 250-500 nm depending on the level of metal-oxide loading, cure temperature, and number of coatings.

  15. Physical properties of Zn doped TiO2 thin films with spray pyrolysis technique and its effects in antibacterial activity

    Science.gov (United States)

    Arunachalam, A.; Dhanapandian, S.; Manoharan, C.; Sivakumar, G.

    2015-03-01

    Zinc doped Titanium dioxide (TiO2: Zn) thin films were deposited onto glass substrates by the spray pyrolysis technique with the substrate temperature 450 °C. The structural, optical, photoluminescence (PL) properties and morphological studies were investigated for the films deposited with various doping concentration (0, 2, 4, 6 and 8 at.%) of zinc. The results of X-ray diffraction (XRD) had shown the presence of anatase peak with a strong orientation along (1 0 1) plane at 8 at.% of Zn-doped TiO2 film. Scanning electron microscopy (SEM) study showed the uniform distribution of grains with porous nature. Atomic force microscopy (AFM) observations indicated the tetragonal shape at 8 at.% of Zn-doped TiO2 with the particle size and decrease in surface roughness. The emission at 398 nm was observed at the 8 at.% of Zn-doped TiO2 thin film. The carrier concentration and Hall mobility was increased with doping. The antibacterial activity was highly yielded for the Zn-doped TiO2 thin films.

  16. Physical properties of Zn doped TiO2 thin films with spray pyrolysis technique and its effects in antibacterial activity.

    Science.gov (United States)

    Arunachalam, A; Dhanapandian, S; Manoharan, C; Sivakumar, G

    2015-03-01

    Zinc doped Titanium dioxide (TiO2: Zn) thin films were deposited onto glass substrates by the spray pyrolysis technique with the substrate temperature 450°C. The structural, optical, photoluminescence (PL) properties and morphological studies were investigated for the films deposited with various doping concentration (0, 2, 4, 6 and 8at.%) of zinc. The results of X-ray diffraction (XRD) had shown the presence of anatase peak with a strong orientation along (101) plane at 8at.% of Zn-doped TiO2 film. Scanning electron microscopy (SEM) study showed the uniform distribution of grains with porous nature. Atomic force microscopy (AFM) observations indicated the tetragonal shape at 8at.% of Zn-doped TiO2 with the particle size and decrease in surface roughness. The emission at 398nm was observed at the 8at.% of Zn-doped TiO2 thin film. The carrier concentration and Hall mobility was increased with doping. The antibacterial activity was highly yielded for the Zn-doped TiO2 thin films. PMID:25479105

  17. Structural and surface properties of TiO2 thin films doped with neodymium deposited by reactive magnetron sputtering

    Science.gov (United States)

    Mazur, Micha?; Kaczmarek, Danuta; Domaradzki, Jaros?aw; Wojcieszak, Damian; Mazur, Piotr; Prociow, Eugeniusz

    2013-01-01

    Thin films were deposited using modified, high energy magnetron sputtering method from Ti-Nd mosaic targets. The amount of neodymium dopant incorporated into two sets of thin films was estimated to be 0.8 and 8.5 at.%, by means of energy dispersive spectroscopy. On the basis of x-ray diffraction method, the type of crystalline structure and crystallites size were evaluated directly after the deposition process and after additional post-process annealing at 800 °C temperature. The influence of annealing on the surface properties was evaluated with the aid of atomic force microscopy. Uniformity of the dopant distribution in titanium dioxide matrix was examined with the aid of secondary ion mass spectroscopy. Additionally, using atomic force microscope, diversification and roughness of the surface was determined. Chemical bonds energy at the surface of TiO2:Nd thin films was investigated by x-ray photoelectron spectroscopy method. Wettability measurements were performed to determine contact angles, critical surface tensions and surface free energy of prepared coatings. On the basis of performed investigations it was found, that both factors, the amount of neodymium dopant and the post-process annealing, fundamentally influenced the physicochemical properties of prepared thin films.

  18. Determination and analysis of dispersive optical constant of TiO2 and Ti2O3 thin films

    International Nuclear Information System (INIS)

    Electron beam evaporation technique was used to prepare TiO2 and Ti2O3 thin films onto glass substrates of thicknesses 50, 500 and 1000nm for each sample. The structural investigations revealed that the as-deposited films are amorphous in nature. Transmittance measurements in the wavelength range (350-2000nm) were used to calculate the refractive index n and the absorption index k using Swanepoel's method. The optical constants such as optical band gap Egopt, optical conductivity ?opt, complex dielectric constant, relaxation time ? and dissipation factor tan? were determined. The analysis of the optical absorption data revealed that the optical band gap Eg was indirect transitions. The optical dispersion parameters Eo and Ed were determined according to Wemple and Didomenico method

  19. Determination and analysis of dispersive optical constant of TiO 2 and Ti 2O 3 thin films

    Science.gov (United States)

    Abdel-Aziz, M. M.; Yahia, I. S.; Wahab, L. A.; Fadel, M.; Afifi, M. A.

    2006-09-01

    Electron beam evaporation technique was used to prepare TiO 2 and Ti 2O 3 thin films onto glass substrates of thicknesses 50, 500 and 1000 nm for each sample. The structural investigations revealed that the as-deposited films are amorphous in nature. Transmittance measurements in the wavelength range (350-2000 nm) were used to calculate the refractive index n and the absorption index k using Swanepoel's method. The optical constants such as optical band gap Egopt, optical conductivity ?opt, complex dielectric constant, relaxation time ? and dissipation factor tan ? were determined. The analysis of the optical absorption data revealed that the optical band gap Eg was indirect transitions. The optical dispersion parameters Eo and Ed were determined according to Wemple and Didomenico method.

  20. Andreev spectroscopy of CrO2 thin films on TiO2 and Al2O3

    Science.gov (United States)

    Yates, K. A.; Anwar, M. S.; Aarts, J.; Conde, O.; Eschrig, M.; Löfwander, T.; Cohen, L. F.

    2013-09-01

    Here we analyse the spectroscopic information gathered at a number of single CrO2/Pb interfaces. We examine thin films requiring additional interfacial layers to generate long-range spin triplet proximity effect superconductivity (CrO2/TiO2) or not (CrO2/Al2O3). We analyse the data using two theoretical models and explore the use of a parameter-free method to determine the agreement between the models and experimental observations, showing the necessary temperature range that would be required to make a definitive statement. The use of the excess current as a further tool to distinguish between models is also examined. The analysis of the spectra demonstrates that the temperature dependence of the normalised zero-bias conductance is independent of the substrate onto which the films are grown. This result has important implications for the engineering of interfaces required for the long-range spin triplet proximity effect.

  1. Photoactivity and hydrophilic property of SiO2 and SnO2 co-doped TiO2 nano-composite thin films

    Directory of Open Access Journals (Sweden)

    Lek Sikong

    2010-08-01

    Full Text Available SiO2 and SnO2 co-doped TiO2 nano-composite thin films were prepared by sol-gel method. The effects of film thicknessand amount of SiO2 and SnO2 co-doping into TiO2 nano-composite films on phase presence, crystallite size, photocatalyticreaction and hydrophilicity were investigated. Thickness of 3-coating layers (238 nm seems to provide the highest photocatalyticactivity. The crystallinity of anatase phases, crystallite sizes and photocatalytic reactions of SiO2 and SnO2 co-dopedTiO2 films decrease with an increase in SiO2 content. It was found that more amount of SiO2 addition seems to inhibit graingrowth and the formation of anatase phase; especially when it was synthesized at temperature less than 600°C. The photocatalyticreaction seems to decrease with an increase in SiO2 doping when the concentrations of SnO2 in the composite films are fixed. It was apparent that 1SiO2/1SnO2/TiO2 composite film exhibits the highest photoactivity. Suitable amounts of SiO2and SnO2 doping into the TiO2 composite films tend to enhance the hydrophilic property of the films. It was also apparentthat the 3SiO2/3SnO2/TiO2, 5SiO2/5SnO2/TiO2 and 10SiO2/3SnO2/TiO2 composite films exhibit super hydrophilic characteristicsunder UV irradiation for 30 min.

  2. Growth of nanocrystalline TiO2 thin films and crystal anisotropy of anatase phase deposited by direct current reactive magnetron sputtering

    International Nuclear Information System (INIS)

    This work describes the growth and elastic anisotropy of nanocrystalline TiO2 films deposited by direct current reactive magnetron sputtering. The films are nanocrystalline in the gas pressure range 0.4–1.0 Pa even in the absence of substrate bias and substrate heating. It has been observed that gas pressure has a considerable effect on the phase evolution of TiO2 and at a higher pressure, nanocrystalline anatase can be produced with a greater crystallinity and dense surface. X-ray diffraction line profile analysis of anatase TiO2 has been performed and the integral breadth expressions of line broadening due to the domain size and lattice microstrain are combined on the basis of the Williamson–Hall (WH) method. The Miller indices dependence of Young's modulus is estimated on the basis of the Reuss approximation for polycrystalline aggregates. Young's modulus shows strong anisotropy. The anisotropic nature of the elastic medium has been introduced in the classical WH plot under the uniform stress deformation model (USDM) and uniform deformation energy density model (UDEDM). USDM represents the better fit of the experimental data. - Highlights: ? Growth of nanocrystalline TiO2 films prepared by reactive magnetron sputtering. ? Anatase grains grow much faster than rutile grains. ? Near band edge luminescence of TiO2 due to oxygen vacancies. ? Facile X-ray line profile analysis for nanocrystalline thin films. ? Elastic anisotropy causes X-ray diffraction line broadening of anatase TiO2

  3. Preillumination of TiO2 and Ta2O5 photoactive thin films as a tool to tailor the synthesis of composite materials.

    Science.gov (United States)

    Sánchez-Valencia, Juan R; Borrás, Ana; Barranco, Angel; Rico, Victor J; Espinós, Juan P; González-Elipe, Agustín R

    2008-09-01

    Illumination of TiO 2 thin films with UV light is known to induce the transformation of the surface of this material from partially hydrophobic into fully hydrophilic. The present work shows that this transformation is accompanied by other effects that may be used to control the synthesis of composite materials. For this purpose, TiO 2 and Ta 2O 5 transparent thin films with a columnar structure and open pores were prepared by electron evaporation at glancing angles. Transparent TiO 2 thin films with micropores (i.e., pores smaller than 2 nm) prepared by plasma enhanced chemical vapor deposition (PECVD) were also used. All these films became hydrophilic upon UV illumination. Rhodamine 6G and Rhodamine 800 dyes were irreversibly adsorbed within the columns of the TiO 2 and Ta 2O 5 thin films by immersion into a water solution of these molecules. Isolated and aggregated molecules of these two dyes were detected by visible absorption spectroscopy. The infiltration adsorption efficiency was directly correlated with the acidity of the medium, increasing at basic pHs as expected from simple considerations based on the concepts of the point of zero charge (PZC) in colloidal oxides. The infiltration experiments were repeated with columnar TiO 2 and Ta 2O 5 thin films that were subjected to preillumination with UV light. It was found that this treatment produced a modification in the type (isolated or aggregated) and amount of dye molecules incorporated into the pores. Moreover, the selective adsorption of a given dye in preilluminated areas of the films permitted the lithographic coloring of the films. Preillumination also controls the UV induced deposition of silver on the surface of the microporous TiO 2 thin films. It was found that the size distribution of the formed silver nanoparticles was dependent on the preillumination treatment and that a well-resolved surface plasmon resonance at around 500 nm was only monitored in the preilluminated films. A model is proposed to account for the effects induced by UV preillumination on the TiO 2 and Ta 2O 5 oxide surfaces. The possibilities of this type of light treatment for the tailored synthesis of nanocomposite thin films (i.e., dye-oxide, metal nanoparticles-oxide) are highlighted. PMID:18642860

  4. Influence of the growth parameters on TiO2 thin films deposited using the MOCVD method Influência dos parâmetros de crescimento em filmes finos de TiO2 depositados pelo método MOCVD

    Directory of Open Access Journals (Sweden)

    M. I. B. Bernardi

    2002-12-01

    Full Text Available In this work we report the synthesis of TiO2 thin films by the Organometallic Chemical Vapor Deposition (MOCVD method. The influence of deposition parameters used during the growth in the obtained structural characteristics was studied. Different temperatures of the organometallic bath, deposition time, temperature and type of the substrate were combined. Using Scanning Electron Microscopy associated to Electron Dispersive X-Ray Spectroscopy, Atomic Force Microscopy and X-ray Diffraction, the strong influence of these parameters in the thin films final microstructure was verified.A síntese de filmes finos de TiO2 por meio do método MOCVD é descrita. Foi estudada a influência de parâmetros de deposição usados durante o crescimento nas características estruturais obtidas. Foram combinados diferentes temperaturas do banho organometálico, tempo de deposição, temperatura e tipo do substrato. A forte influência destes parâmetros na microestrutura final dos filmes foi estudada por meio de diferentes técnicas: microscopia eletrônica de varredura associada com espectroscopia eletrônica de dispersão de raios X, microscopia de força atômica e difração de raios X.

  5. Influence of the growth parameters on TiO2 thin films deposited using the MOCVD method / Influência dos parâmetros de crescimento em filmes finos de TiO2 depositados pelo método MOCVD

    Scientific Electronic Library Online (English)

    M. I. B., Bernardi; E. J. H., Lee; P. N., Lisboa-Filho; E. R., Leite; E., Longo; A. G., Souza.

    2002-12-01

    Full Text Available A síntese de filmes finos de TiO2 por meio do método MOCVD é descrita. Foi estudada a influência de parâmetros de deposição usados durante o crescimento nas características estruturais obtidas. Foram combinados diferentes temperaturas do banho organometálico, tempo de deposição, temperatura e tipo d [...] o substrato. A forte influência destes parâmetros na microestrutura final dos filmes foi estudada por meio de diferentes técnicas: microscopia eletrônica de varredura associada com espectroscopia eletrônica de dispersão de raios X, microscopia de força atômica e difração de raios X. Abstract in english In this work we report the synthesis of TiO2 thin films by the Organometallic Chemical Vapor Deposition (MOCVD) method. The influence of deposition parameters used during the growth in the obtained structural characteristics was studied. Different temperatures of the organometallic bath, deposition [...] time, temperature and type of the substrate were combined. Using Scanning Electron Microscopy associated to Electron Dispersive X-Ray Spectroscopy, Atomic Force Microscopy and X-ray Diffraction, the strong influence of these parameters in the thin films final microstructure was verified.

  6. Influence of the growth parameters of TiO2 thin films deposited by the MOCVD method / Influência dos parâmetros de crescimento de filmes finos de TiO2 depositados pelo método MOCVD

    Scientific Electronic Library Online (English)

    M. I. B., Bernardi; E. J. H., Lee; P. N., Lisboa-Filho; E. R., Leite; E., Longo; A. G., Souza.

    2002-03-01

    Full Text Available A síntese de filmes finos de TiO2 foi feita pelo método de deposição química do vapor de organometálicos (MOCVD). Foi estudada a influência de parâmetros de deposição usados durante o crescimento, nas características estruturais finais. Foi feita uma combinação de vários parâmetros experimentais: te [...] mperatura do banho do organometálico, tempo de deposição, e temperatura e tipo do substrato. A forte influência destes parâmetros na microestrutura final do filme foi analisada por microscopia eletrônica de varredura com espectroscopia de raios X dispersiva de elétrons, microscopia de força atômica e difração de raios X. Abstract in english The synthesis of TiO2 thin films was carried out by the Organometallic Chemical Vapor Deposition (MOCVD) method. The influence of deposition parameters used during growth on the final structural characteristics was studied. A combination of the following experimental parameters was studied: temperat [...] ure of the organometallic bath, deposition time, and temperature and substrate type. The high influence of those parameters on the final thin film microstructure was analyzed by scanning electron microscopy with electron dispersive X-ray spectroscopy, atomic force microscopy and X-ray diffraction.

  7. Influence of the growth parameters of TiO2 thin films deposited by the MOCVD method Influência dos parâmetros de crescimento de filmes finos de TiO2 depositados pelo método MOCVD

    Directory of Open Access Journals (Sweden)

    M. I. B. Bernardi

    2002-03-01

    Full Text Available The synthesis of TiO2 thin films was carried out by the Organometallic Chemical Vapor Deposition (MOCVD method. The influence of deposition parameters used during growth on the final structural characteristics was studied. A combination of the following experimental parameters was studied: temperature of the organometallic bath, deposition time, and temperature and substrate type. The high influence of those parameters on the final thin film microstructure was analyzed by scanning electron microscopy with electron dispersive X-ray spectroscopy, atomic force microscopy and X-ray diffraction.A síntese de filmes finos de TiO2 foi feita pelo método de deposição química do vapor de organometálicos (MOCVD. Foi estudada a influência de parâmetros de deposição usados durante o crescimento, nas características estruturais finais. Foi feita uma combinação de vários parâmetros experimentais: temperatura do banho do organometálico, tempo de deposição, e temperatura e tipo do substrato. A forte influência destes parâmetros na microestrutura final do filme foi analisada por microscopia eletrônica de varredura com espectroscopia de raios X dispersiva de elétrons, microscopia de força atômica e difração de raios X.

  8. The effect of aeration and solar intensity power on photocatalytic degradation of textile industrial wastewater using TiO2 thin film

    International Nuclear Information System (INIS)

    Solar photo catalytic degradation of the textile industry wastewater using TiO2 thin films was studied. This experiment was performed to investigate the effect of aeration and solar intensity power on decreasing of Chemical Oxygen Demand (COD). A serpentine flow photo catalytic reactor was developed for this purpose. TiO2 thin films photo catalyst supported on the stainless steel 304 substrates were prepared using sol-gel dip coating method. The results of thin films were characterized by Scanning Electron Microscopy (SEM) and X-Ray Diffractometer (XRD). XRD result showed that the prepared thin films gave the anatase crystallite formation whilst SEM demonstrated the macro pores were formed. Finally, the aeration and solar intensity power factors are considered to be responsible for the photo catalytic degradation. (Author)

  9. Surface segregation in TiO2-based nanocomposite thin films

    International Nuclear Information System (INIS)

    The morphology of nanocomposites plays a pivotal role in understanding their functionality and determines their capabilities for applications. The use of nanocomposite coatings requires a study of the size effects on their functional properties. Noble metal nanoparticles are promising candidates for nanocomposite thin film applications due to their antibacterial, plasmonic and photocatalytic properties. In this contribution, the morphology of Ag–TiO2 and Au–TiO2 nanocomposite thin films has been investigated experimentally using electron tomography in transmission electron microscopy in combination with UV/vis spectroscopy. Based on the additional 3D information obtained from tomography, we propose a two-step model towards the observed bimodal particle size in these nanocomposite thin films prepared by co-sputtering from two different sources. Furthermore, we show that the optical properties exhibit a well-defined relation with the morphology of the nanocomposite thin films. The present investigations demonstrate the potential of electron tomography for revealing the complex structure and formation processes of functional nanocomposites. (paper)

  10. The photocatalytic application and regeneration of anatase thin films with embedded commercial TiO2 particles deposited on glass microrods

    International Nuclear Information System (INIS)

    Anatase thin films (2 were prepared by sol-gel method. TiO2-anatase thin films were deposited on a fiberglass substrate and then ground to obtain glass microrods containing the composite films. The film structure was characterized using Raman spectroscopy, atomic absorption and UV-vis spectrophotometry, and atomic force microscopy. The photocatalytic activity of the composite films, calcined at 450 deg. C, and the regeneration of the activity under the same experimental conditions, were assessed using gas chromatography to study the photodegradation of phenol, an industrial pollutant, in water under 365 nm irradiation. The film with 15.0 wt.% of P25 TiO2 was found to be more photoactive (54 ppm of degraded phenol at 6 h of illumination) than the other ones

  11. Creating high quality Ca:TiO2-B (CaTi5O11) and TiO2-B epitaxial thin films by pulsed laser deposition.

    Science.gov (United States)

    Zhang, Kui; Du, Xianfeng; Katz, Michael B; Li, Baihai; Kim, Sung Joo; Song, Kaixin; Graham, George W; Pan, Xiaoqing

    2015-05-01

    We demonstrate, in great detail, a completely waterless synthesis route to produce highly crystalline epitaxial thin films of TiO2-B and its more stable variant CaTi5O11, using pulsed laser deposition (PLD). PMID:25853927

  12. Thermo-Optical Properties of Thin-Film TiO2–Al2O3 Bilayers Fabricated by Atomic Layer Deposition

    Directory of Open Access Journals (Sweden)

    Rizwan Ali

    2015-05-01

    Full Text Available We investigate the optical and thermo-optical properties of amorphous TiO\\(_2\\–Al\\(_2\\O\\(_3\\ thin-film bilayers fabricated by atomic layer deposition (ALD. Seven samples of TiO\\(_2\\–Al\\(_2\\O\\(_3\\ bilayers are fabricated by growing Al\\(_2\\O\\(_3\\ films of different thicknesses on the surface of TiO\\(_2\\ films of constant thickness (100 nm. Temperature-induced changes in the optical refractive indices of these thin-film bilayers are measured by a variable angle spectroscopic ellipsometer VASE\\textsuperscript{\\textregistered}. The optical data and the thermo-optic coefficients of the films are retrieved and calculated by applying the Cauchy model and the linear fitting regression algorithm, in order to evaluate the surface porosity model of TiO\\(_2\\ films. The effects of TiO\\(_2\\ surface defects on the films' thermo-optic properties are reduced and modified by depositing ultra-thin ALD-Al\\(_2\\O\\(_3\\ diffusion barrier layers. Increasing the ALD-Al\\(_2\\O\\(_3\\ thickness from 20 nm to 30 nm results in a sign change of the thermo-optic coefficient of the ALD-TiO\\(_2\\. The thermo-optic coefficients of the 100 nm-thick ALD-TiO\\(_2\\ film and 30 nm-thick ALD-Al\\(_2\\O\\(_3\\ film in a bilayer are (0.048 \\(\\pm\\ 0.134 \\(\\times 10 ^{-4} {^\\circ}\\mathrm {C}^{-1}\\ and (0.680 \\(\\pm\\ 0.313 \\(\\times 10^{-4} {^\\circ} \\mathrm {C}^{-1}\\, respectively, at a temperature \\(T = 62 ^\\circ \\mathrm{C}\\.

  13. Studies of LPCVD and anodised TiO2 thin films and their photoelectrocatalytic photochemical properties for destruction of organic effluents

    International Nuclear Information System (INIS)

    TiO2 thin films prepared by CVD and anodisation methods and their applications for the photoelectrocatalytic and photocatalytic destruction of organic effluents are described in this thesis. The theoretical background of CVD, photoelectrocatalysis (PEC) and photocatalysis (PC) is introduced in Chapter 1. This chapter also contains an intensive literature review about TiO2 thin film preparation, mainly by CVD, and about PEC and PC destruction of organic effluents by TiO2 thin films. The experimental methods, which include CVD reactors, PEC cells and film characterisation and chemical analysis, are described in Chapter 2. The results for TiO2 films deposited by LPCVD on SnO2 coated glass using either TTIP or TTB precursors in the presence of O2, with or without water as a reagent, are discussed in Chapter 3 for a small CVD reactor and Chapter 4 for a large reactor. The effects of precursor, water and annealing on the crystal structure of the films have been investigated and compared. It was found that phase transition temperatures for changes from amorphous to anatase and anatase to rutile with TTIP were higher than those obtained with TTB. Water also had an effect by decreasing the temperature for depositing crystalline films. The other kind of TiO2 films prepared by anodisation of titanium mesh was studied and the results are presented in Chapter 5. PEC or PC destruction of MPA, RDX and 4-CP EC or PC destruction of MPA, RDX and 4-CP have been studied using TiO2 thin film anodes in small and large PEC reactors which are described in Chapter 6 and Chapter 7, respectively. PC destruction rates of organics are found to be improved significantly with an applied potential; i.e. by a PEC process. The effects of film properties, such as film crystallinity, thickness and film type on the PEC and PC efficiencies have been investigated. It was found that the different behaviour of films in PEC processes probably was due to surface effects rather than internal electric field differences. The extent of PEC and PC destruction of organics for CVD films was higher than for anodised films. The thesis concludes with an overall summary of the results and some suggestions for future work (Chapter 8). (author)

  14. Undoped and Cr-doped TiO2 thin films obtained by spray pyrolysis

    International Nuclear Information System (INIS)

    Undoped and chromium doped titanium oxide thin films were fabricated by spray pyrolysis by using a solution of titanium tetrachloride and ethyl alcohol. The films have been deposited on heated glass substrates at 373 K. After annealing for 90 min at 723 K, the initially amorphous films became polycrystalline with a predominant anatase structure and average crystallite sizes depending on dopant (Cr) concentration. The repartition of chromium impurities in the matrix of titanium oxide films, analyzed by electron paramagnetic resonance and X-ray photoelectron spectroscopy showed that the entrance of chromium into the anatase structure is mainly achieved by substitution. A decrease in unit cell parameters ratio (c/a) with the increase of chromium content sustains this assertion. The wetting properties of the titanium oxide films were evaluated from contact angle measurements between de-ionized water and films surface during- and post-irradiation with UV light. The correlation between the concentration of the dopant, film structure, surface morphology and wettability characteristics is discussed.

  15. Molecular Interaction of Thin Film Photosensitive Organic Dyes on TiO2 Surfaces

    OpenAIRE

    Yu, Shun

    2011-01-01

    The photosensitive molecule adsorption on titanium dioxide (TiO2) forms the so-called “dye sensitized TiO2” system, a typical organic/oxide heterojunction, which is of great interest in catalysis and energy applications, e.g. dye-sensitized solar cell (DSSC). Traditionally, the transition metal complex dyes are the focus of the study. However, as the fast development of the organic semiconductors and invention of new pure organic dyes, it is necessary to expand the research horizon to cov...

  16. Effect of TiO2 nanopatterns on the performance of hydrogenated amorphous silicon thin-film solar cells

    International Nuclear Information System (INIS)

    We investigate how TiO2 nanopatterns formed onto ZnO:Al (AZO) films affect the performance of hydrogenated amorphous silicon (a-Si:H) solar cells. Scanning electron microscopy results show that the dome-shaped TiO2 nanopatterns (300 nm in diameter) having a period of 500 nm are formed onto AZO films and vary from 60 to 180 nm in height. Haze factor increases with an increase in the height of the nanopatterns in the wavelength region below 530 nm. Short circuit current density also increases with an increase in the height of the nanopatterns. As the nanopatterns increases in height, the fill factor of the cells slightly increases, reaches maximum (0.64) at 100 nm, and then decreases. Measurements show that a-Si:H solar cells fabricated with 100 nm-high TiO2 nanopatterns exhibit the highest conversion efficiency (6.34%) among the solar cells with the nanopatterns and flat AZO sample. - Highlights: ? We investigated the height effect of TiO2 nanopatterns on the a-Si:H solar cells. ? Light scattering and anti-reflection were introduced by TiO2 nanopatterns. ? a-Si:H Solar cells with the 100 nm-high TiO2 nanopatterns showed highest efficiency.

  17. An In-situ Real-Time Optical Fiber Sensor Based on Surface Plasmon Resonance for Monitoring the Growth of TiO2 Thin Films

    Directory of Open Access Journals (Sweden)

    Wen-Ching Shih

    2013-07-01

    Full Text Available An optical fiber sensor based on surface plasmon resonance (SPR is proposed for monitoring the thickness of deposited nano-thin films. A side-polished multimode SPR optical fiber sensor with an 850 nm-LD is used as the transducing element for real-time monitoring of the deposited TiO2 thin films. The SPR optical fiber sensor was installed in the TiO2 sputtering system in order to measure the thickness of the deposited sample during TiO2 deposition. The SPR response declined in real-time in relation to the growth of the thickness of the TiO2 thin film. Our results show the same trend of the SPR response in real-time and in spectra taken before and after deposition. The SPR transmitted intensity changes by approximately 18.76% corresponding to 50 nm of deposited TiO2 thin film. We have shown that optical fiber sensors utilizing SPR have the potential for real-time monitoring of the SPR technology of nanometer film thickness. The compact size of the SPR fiber sensor enables it to be positioned inside the deposition chamber, and it could thus measure the film thickness directly in real-time. This technology also has potential application for monitoring the deposition of other materials. Moreover, in-situ real-time SPR optical fiber sensor technology is in inexpensive, disposable technique that has anti-interference properties, and the potential to enable on-line monitoring and monitoring of organic coatings.

  18. Fabrication and characterization of TiO2 thin film prepared by a layer-by-layer self-assembly method

    International Nuclear Information System (INIS)

    Titanium dioxide (TiO2) thin films assembled with TiO2 nanoparticles and oppositely charged polyelectrolytes or titanium (IV) bis(ammonium lactato) dihydroxide (TALH) were successfully fabricated via a layer-by-layer (LBL) self-assembly method at room temperature. Especially, by using the quartz crystal microbalance (QCM) to monitor the in-situ deposition phenomenon of TALH that is saturated and then separated from the film before and after the deposition of 30 s at low pH, the anatase TiO2 multilayer films fabricated with 30 s deposition in TALH adjusted to pH 2.5 showed a higher refractive index (ca. n = 1.75), a denser film growth, and a lower surface roughness (ca. 10.5 nm) than those of the films deposited in different conditions. This film showed a high transmittance in visible range for optical applications and photocatalytic properties by decomposing methyl orange molecules gradually according to UV irradiation time. In addition, as the pH of TALH was decreased from pH 5.5 to 2.0, the thickness of (TiO2 / TALH)3 film was increased from ca. 85 nm to ca. 442 nm

  19. Preparation of TiO2/SnO2 thin films by sol-gel method and periodic B3LYP simulations.

    Science.gov (United States)

    Floriano, Emerson A; Scalvi, Luis V A; Saeki, Margarida J; Sambrano, Julio R

    2014-08-01

    Titanium dioxide (TiO2) thin films are grown by the sol-gel dip-coating technique, in conjunction with SnO2 in the form of a heterostructure. It was found that the crystalline structure of the most internal layer (TiO2) depends on the thermal annealing temperature and the substrate type. Films deposited on glass substrate submitted to thermal annealing until 550 °C present anatase structure, whereas films deposited on quartz substrate transform to rutile structure at much higher temperatures, close to 1000 °C, unlike powder samples where the phase transition takes place at about 780 °C. When structured as rutile, the oxide semiconductors TiO2/SnO2 have very close lattice parameters, making the heterostructure assembling easier. The SnO2 and TiO2 have their electronic properties evaluated by first-principles calculations by means of DFT/B3LYP. Taking into account the calculated band structure diagram of these materials, the TiO2/SnO2 heterostructure is qualitatively investigated and proposed to increase the detection efficiency as gas sensors. This efficiency can be further improved by doping the SnO2 layer with Sb atoms. This assembly may be also useful in photoelectrocatalysis processes. PMID:24824227

  20. Investigation of Solar Energy Transfer through Plasmonic Au Nanoparticle-doped Sol-derived TiO2 Thin Films in Photocatalysis and Photovoltaics

    Science.gov (United States)

    Zelinski, Andrew

    Titanium Dioxide (TiO2) films were elaborated using the Sol-Gel technique and subsequently used to study plasmonic photovoltaic and photocatalytic energy transfer enhancement mechanisms. TiO2 was chosen because of the unique optical and electrical properties it possesses as well as its ease of preparation and operational stability. The properties of sol-elaborated films vary significantly with processing environment and technique, and the sol formula; a systematic investigation of these variables enabled the selection of a consistent technique to produce relatively dense, crack-free TiO2 thin films. Localized Surface Plasmon Resonance (LSPR) energy transfer was investigated by integrating plasmonic Au nanoparticles into multi-layer wide-band gap semiconductor (TiO2) devices, and by doping strongly catalytic TiO2 anodes in a 3-electrode photochemical cell. An instant 3x photocurrent enhancement in the multilayer solar cell device was observed under 650nm light illumination, which suggests the presence of a resonant energy transfer. The focus of this work was to develop a systematic analysis of the actual mechanics of energy transfer responsible for the light-harvesting enhancements seen in previous studies of Au nanoparticle-TiO2 systems under visible illumination. This mechanism remains the subject of debate and models have been proposed by various researchers. A method is developed here to pinpoint the most influential of the proposed mechanisms.

  1. Reliability of ultra-thin titanium dioxide (TiO2) films on strained-Si

    International Nuclear Information System (INIS)

    Ultra-thin high-k titanium oxide (equivalent oxide thickness ? 2.2 nm) films have been deposited on strained-Si/relaxed-Si0.8Ge0.2 heterolayers using titanium tetrakis iso-propoxides (TTIP) as an organometallic source at low temperature (2 gate dielectric during constant current (CCS) and voltage stressing (CVS) has been investigated. Normalized trapping centroid and trapped charge density variation with injected fluences have been investigated and also empirically modeled. Oxide lifetime is predicted using empirical reliability model developed. Dielectric breakdown and reliability of the dielectric films have been studied using constant voltage stressing. A high time-dependent dielectric breakdown (TDDB, tbd > 1000 s) is observed under high constant voltage stress

  2. Light-emitting diode applications of colloidal CdSe/ZnS quantum dots embedded in TiO2-? thin film

    International Nuclear Information System (INIS)

    We report the light-emitting diode (LED) characteristics of colloidal core-shell CdSe/ZnS nanocrystal quantum dots (QDs) embedded in TiO2-? thin films on Si substrate. High-quality CdSe/ZnS QDs were synthesized via a pyrolysis in the range of 220-280 C. The QDs were embedded in TiO2-? thin film at 200 C by plasma-enhanced metallorganic chemical vapor deposition. The diode structure of n-TiO2-?/QDs/p-Si showed electroluminescence characteristics, indicating the possibility of LED applications of colloidal CdSe/ZnS nanocrystal QDs embedded in oxide films on large-area Si wafer. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  3. Influence of surfactant and annealing temperature on optical properties of sol-gel derived nano-crystalline TiO 2 thin films

    Science.gov (United States)

    Vishwas, M.; Sharma, Sudhir Kumar; Rao, K. Narasimha; Mohan, S.; Gowda, K. V. Arjuna; Chakradhar, R. P. S.

    2010-03-01

    Titanium dioxide thin films have been synthesized by sol-gel spin coating technique on glass and silicon substrates with and without surfactant polyethylene glycol (PEG). XRD and SEM results confirm the presence of nano-crystalline (anatase) phase at an annealing temperature of 300 °C. The influence of surfactant and annealing temperature on optical properties of TiO 2 thin films has been studied. Optical constants and film thickness were estimated by Swanepoel's (envelope) method and by ellipsometric measurements in the visible spectral range. The optical transmittance and reflectance were found to decrease with an increase in PEG percentage. Refractive index of the films decreased and film thickness increased with the increase in percentage of surfactant. The refractive index of the un-doped TiO 2 films was estimated at different annealing temperatures and it has increased with the increasing annealing temperature. The optical band gap of pure TiO 2 films was estimated by Tauc's method at different annealing temperature.

  4. Nanostructured columnar heterostructures of TiO2 and Cu2O enabled by a thin-film self-assembly approach: Potential for photovoltaics

    International Nuclear Information System (INIS)

    Graphical abstract: Display Omitted Highlights: ? Material self-assembly in phase-separated oxides is exploited. ? Three-dimensionally nanostructured epitaxial films are grown using sputtering. ? Films are composed of well-ordered oriented nanopillars of n-type TiO2 and p-type Cu2O. ? Observed interfaces at adjacent TiO2–Cu2O columns are nearly atomically distinct. ? Absorption profile of the composite film captures a wide range of the solar spectrum. -- Abstract: Significant efforts are being devoted to the development of multifunctional thin-film heterostructures and nanostructured material architectures for components with novel applications of superconductivity, multiferroicity, solar photocatalysis and energy conversion. In particular, nanostructured assemblies with well-defined geometrical shapes have emerged as possible high efficiency and economically viable alternatives to planar photovoltaic thin-film architectures. By exploiting phase-separated self-assembly, here we present advances in a vertically oriented two-component system that offers potential for future development of nanostructured thin film solar cells. Through a single-step deposition by magnetron sputtering, we demonstrate growth of an epitaxial, composite film matrix formed as self-assembled, well ordered, phase segregated, and oriented nanopillars of n-type TiO2 and p-type Cu2O. The composite films were structurally characterized to atomic resolution by a variety of analytical tools, and evaluated for preliminary optical properties using absorption measurements. We find nearly atomically distinct TiO2–Cu2O interfaces (i.e., needed for possible active p–n junctions), and an absorption profile that captures a wide range of the solar spectrum extending from ultraviolet to visible wavelengths. This high-quality materials system could lead to photovoltaic devices that can be optimized for both incident light absorption and carrier collection.

  5. TiO2 thin films with rutile phase prepared by DC magnetron co-sputtering at room temperature: Effect of Cu incorporation

    Science.gov (United States)

    Wang, Hui; Li, Yujie; Ba, Xin; Huang, Lin; Yu, Ying

    2015-08-01

    The thin films for pure TiO2 and that incorporated with Cu ion were deposited by DC magnetron co-sputtering with Ar gas. The crystal texture, surface morphology, energy gap and optical properties of the prepared films have been investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectrometer (XPS), UV-vis spectrophotometer, and Raman spectroscopy. The results show that as-deposited TiO2 film mainly possesses anatase structure at room temperature with pure Ar gas, but the introduction of Cu can alter the phase structure of crystallite TiO2. XRD patterns and Raman spectra indicate that the Cu incorporation with high concentration (ACu/ATi + ACu ? 20%) favors the formation of rutile phase. Moreover, the Cu incorporation into TiO2 lattice induces band gap narrowing. Band structures and density of states have been analyzed based on density functional theory (DFT) and periodic models in order to investigate the influence of the Cu incorporation on the electronic structure of TiO2. Both experimental data and electronic structure calculations evidence the fact that the change in film structure from the anatase to the rutile phase can be ascribed to the possible incorporation of Cu1+ in the sites previously occupied by Ti4+, and the presence of Cu results in important effect on the electronic states, which is mainly related to the 3d Cu orbitals in the gap and in the vicinity of the valence band edges for TiO2.

  6. Investigation of reactive HiPIMS + MF sputtering of TiO2 crystalline thin films.

    Czech Academy of Sciences Publication Activity Database

    Olejní?ek, Ji?í; Hubi?ka, Zden?k; Kment, Št?pán; ?ada, Martin; Kšírová, Petra; Adámek, Petr; Gregora, Ivan

    2013-01-01

    Ro?. 232, OCT (2013), s. 376-383. ISSN 0257-8972 R&D Projects: GA MŠk LH12045; GA ?R GAP108/12/1941; GA MŠk LD12002; GA ?R GAP108/12/2104; GA MŠk LH12043 Institutional support: RVO:68378271 Keywords : HiPIMS * mid-frequency * ion velocity distribution function * TiO 2 * rutile Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.199, year: 2013 http://www.sciencedirect.com/science/article/pii/S0257897213004829

  7. Structural and morphological properties of TiO2thin films prepared by spray pyrolysis

    Directory of Open Access Journals (Sweden)

    N. Castillo

    2004-01-01

    Full Text Available En el presente trabajo la técnica de roc?o pirol?tico fue empleada para producir pel?culas delgadas de TiO2 sobre substratos de cuarzo y silicio cristalino (Si. Generado por ultrasonido, un aerosol de di-isopropoxido de titanio fue usado como precursor en los depósitos. El proceso de cristalización como función de los parámetros de deposito fue estudiado por difracción de rayos-X (XRD, espectroscop?a Rama (RS, microscopia de fuerza atómica (AFM y espectroscop?a óptica de transmisión (TS. Los resultados demuestran que la técnica de roc?o pirol?tico puede producir pel?culas con superficies planas y buenas propiedades cristalinas. Cuando la temperatura de depósito es menor a 400±C, la pel?cula crece con una superficie suave (rugosidad»5 ° A pero en una fase amorfa; sin embargo a temperaturas iguales a 400±C o mayores las pel?culas cristalizan en la fase anatasa aun cuando la rugosidad se incrementa hasta un valor que depende del espesor. Después de un tratamiento térmico a 750±C, las muestras depositadas sobre Si muestran una transicion parcial a la fase rutilio del TiO2con orientación preferencial (111; sin embargo, las pel?culas depositadas sobre cuarzo no muestran tal transicion.

  8. Raman spectroscopy of TiO2 thin films formed by hybrid treatment for biomedical applications.

    Science.gov (United States)

    Lubas, M; Jasinski, J J; Sitarz, M; Kurpaska, L; Podsiad, P; Jasinski, J

    2014-12-10

    The paper presents the results of the investigations of the surface layer obtained after application of the combined hybrid method of oxidation in a fluidized bed (FB) and deposition of the oxide coating by PVD technique. The material used in the study was Ti Grade 2. The process of diffusive saturation was carried out in a fluidized-bed reactor at the temperature of 640°C for 8h in air while the top oxide layer was obtained through PVD method - magnetron sputtering using TiO2 target and argon atmosphere with the pressure of 3×10(-2)mbar and the distance between the substrate to the target of 60mm. In order to determine changes in the properties that occur as a result of modification of the Ti surface, the following examinations were carried out by SEM-EDX, X-ray diffraction methods, Raman spectroscopy, Glow Discharge Optical Spectroscopy (GDOS) and Secondary Ion Mass Spectrometry (SIMS). The coatings obtained were characterized by zonal structure comprising the solution zone of Ti?(O) and oxide zone of TiO2 with modifications of rutile and anatase, depending on the oxidation method. It was found that formation of oxide layers using the hybrid method (FB+PVD) leads to limitation of defects in the oxide layer after fluidized-bed thermal treatment and obtaining a uniform, tight coating with improved corrosion properties which are important from the biomedical standpoint. PMID:25037440

  9. The fabrication of visible light responsive Ag-SiO2 co-doped TiO2 thin films by the sol–gel method

    International Nuclear Information System (INIS)

    In this study we have successfully deposited Ag-SiO2 co-doped TiO2 thin films on glass substrates by the sol–gel method. After being coated by a dip coating method, the film was transparent, smooth and had strong adhesion on the glass surface. The deposited film was characterized by x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy (UV–Vis), a scanning electron microscope (SEM) and atomic force microscope (AFM) to investigate its crystallization, transmittance and surface structure. The antifogging ability is explained by the contact angle of water on the surface of the glass substrates under visible-light. The obtained results show that Ag-SiO2 co-doped TiO2 film has potential applications for self cleaning and anti-bacterial ceramic tiles

  10. Effects of dip-coating speed and annealing temperature on structural, morphological and optical properties of sol-gel nano-structured TiO2 thin films

    Science.gov (United States)

    Touam, Tahar; Atoui, Mohamed; Hadjoub, Ilhem; Chelouche, Azeddine; Boudine, Boubekeur; Fischer, Alexis; Boudrioua, Azzedine; Doghmane, Abdellaziz

    2014-09-01

    We reported material characterization of the nano-structured TiO2 thin films prepared by the sol-gel dip-coating process on glass substrates. The dependence of the structural, morphological and optical properties of the synthesized films on the fabrication parameters such as withdrawal velocity and annealing temperature were investigated by the techniques of X-ray diffraction (XRD), Raman spectroscopy (RS), scanning electron microscopy (SEM), atomic force microscopy (AFM) and UV-visible spectrophotometry. The results indicate that for the TiO2 films annealed at 500 °C there exhibits (1 0 1) XRD peak corresponding to the anatase phase of TiO2. The latter is consistent with the recorded Raman signal observed at 142 cm-1 (Eg mode) and 391 cm-1 (B1g mode), respectively. From the analyses made on the SEM micrographs and AFM images, it was revealed that the morphology and surface roughness of the thin films would depend on the withdrawal speed and the heat treatment temperature. The UV-visible spectroscopy analyses show that all the films were transparent in the visible region with an average transmittance of more than 70%. With an increase on the dip-coating speed from 1 cm/min to 3 cm/min, we observed a spectral red shift of the absorption edge from 3.76 eV to 3.71 eV, indicating a decrease in the bandgap energy (Eg) of the films.

  11. Corrosion behavior of TiO2–NiO nanocomposite thin films on AISI 316L stainless steel prepared by sol–gel method

    International Nuclear Information System (INIS)

    TiO2–NiO nanocomposite thin films were deposited on the 316L stainless steel using sol–gel method by a dip coating technique. Different techniques such as differential thermal analysis, thermogravimetric analysis, X-ray diffraction, Fourier transform infrared spectrometry, scanning electron microscopy and scanning probe microscopy were carried out in order to characterize the structure of the coatings. The corrosion resistance of the coatings was evaluated by using Tafel polarization and electrochemical impedance spectroscopy tests of uncoated and coated specimens in a 3.5% NaCl solution at room temperature. It was found that to obtain desirable structure in coatings, the coatings should be calcined at 600 °C for one and half hour. NiTiO3, anatase and rutile were the phases obtained in different calcination conditions in air atmosphere. The results of corrosion tests indicated that with increasing the dipping times from 2 to 4, the corrosion current density first decreases but when increasing the dipping times to 6, it increases. Also the corrosion current density decreased from 186.7 nA.cm?2 (uncoated steel) to 34.21 nA.cm?2 (80%TiO2–20%NiO) and corrosion potential increased from ? 150.2 mV (uncoated steel) to ? 107.3 mV (67%TiO2–33%NiO). - Highlights: ? TiO2–NiO thin films were deposited on the 316L stainless steel using sol–gel method. ? Different compositions, anncompositions, annealing times and temperatures resulted in various phases. ? Films having different compositions showed various surface morphologies. ? Films having a composition of 80%TiO2–20%NiO showed a good corrosion protection.

  12. Vibrational relaxation dynamics of catalysts on TiO2 Rutile (1 1 0) single crystal surfaces and anatase nanoporous thin films

    International Nuclear Information System (INIS)

    Highlights: • Investigated vibrational relaxation dynamics of a CO2-reduction catalyst on TiO2 surfaces. • IR pump-vibration sum-frequency generation probe spectroscopy on Rutile (1 1 0) surface. • IR-pump/IR probe transient absorption spectroscopy on nano-crystalline thin films. • CO stretching modes show a ultrafast population equilibration followed by population decay. - Abstract: Time-resolved vibrational sum frequency generation (VSFG) spectroscopy has been used to investigate the vibrational relaxation dynamics of the rhenium bipyridyl CO2-reduction catalyst Re(CO)3Cl(dcbpy) [dcbpy = 4,4?-dicarboxy-2,2?-bipyridine] adsorbed onto the (1 1 0) surface of a Rutile TiO2 single crystal. IR pump-VSFG probe spectra of the a?(1) CO stretching mode indicate a ultrafast population equilibration between three CO stretching modes followed by their population relaxation via intramolecular vibrational energy transfer. Similar vibational relaxation dynamics was also observed for the same complex on anatase TiO2 nanocrystalline thin films measured by IR pump-IR probe transient absorption spectroscopy. The relaxation dynamics of ReCOA on TiO2, in DMF solution, and immobilized on Au through alkane thiol linkers were compared to examine possible effects of adsorbate-TiO2 interaction

  13. Atomic layer deposition of TiO2 thin films on nanoporous alumina templates: Medical applications

    Science.gov (United States)

    Narayan, Roger J.; Monteiro-Riviere, Nancy A.; Brigmon, Robin L.; Pellin, Michael J.; Elam, Jeffrey W.

    2009-06-01

    Nanostructured materials may play a significant role in controlled release of pharmacologic agents for treatment of cancer. Many nanoporous polymer materials are inadequate for use in drug delivery. Nanoporous alumina provides several advantages over other materials for use in controlled drug delivery and other medical applications. Atomic layer deposition was used to coat all the surfaces of a nanoporous alumina membrane in order to reduce the pore size in a controlled manner. Neither the 20 nm nor the 100 nm TiO2-coated nanoporous alumina membranes exhibited statistically lower viability compared to the uncoated nanoporous alumina membrane control materials. Nanostructured materials prepared using atomic layer deposition may be useful for delivering a pharmacologic agent at a precise rate to a specific location in the body. These materials may serve as the basis for “smart” drug delivery devices, orthopedic implants, or self-sterilizing medical devices.

  14. Thin-film photo-catalytic TiO2 phase prepared by magnetron sputtering deposition, plasma ion implantation and metal vapor vacuum arc source

    International Nuclear Information System (INIS)

    This study utilizes three methods, magnetron sputtering deposition (MSD), plasma ion implantation (PIII), and metal vapor vacuum arc (MeVVA), to prepare a thin-film TiO2. The formation of stoichiometrical TiO2-polymorphs as a layer is regularly relevant to the characteristic of the photo-catalytic effect. TiO2-polymorphs created at the outermost surface and initiated by efficient photons are still capable to produce superficial hydroxyl groups for subsequent photo-catalytic reactions. The MSD-treated surface with the majority of TiO2-anatase (101) surface is presently photo-catalytic. The PIII or MeVVA treatment results in an ion-implanted layer of different Ti / O ratios along with the detecting depths, whereas the Ti and O elements in TiO2 phase at the outermost surface of the layer can be distinguished. Although the PIII- or MeVVA-treated surface is relatively insignificant in photo-catalytic reactions assessed by water droplet contact angle, the consumption of methylene blue in water and antibacterial test, it is still potential to adjust their surface chemistry by improving the quality of the ion-implanted layer, roughening the contact surface area, and increasing the efficiency to regenerate the photo-catalytic reactions. In addition, the ion implantation methods do not alter the size and dimension of a substrate that is a great advantage to employ them for various advanced applicationsdvanced applications

  15. Effect of an Al2O3/TiO2 Passivation Layer on the Performance of Amorphous Zinc-Tin Oxide Thin-Film Transistors

    Science.gov (United States)

    Han, Dong-Suk; Park, Jae-Hyung; Kang, Min-Soo; Shin, So-Ra; Jung, Yeon-Jae; Choi, Duck-Kyun; Park, Jong-Wan

    2015-02-01

    The effect of an Al2O3/TiO2 stacked passivation layer on the performance of amorphous ZnSnO ( a-ZTO) thin-film transistors (TFTs) was investigated by comparing field-effect mobility ( ? FE) and subthreshold swing after passivation layer deposition. The values observed were 4.7 cm2/Vs and 0.64 V/decade, respectively, for uncoated TFTs and 4.6 cm2/Vs and 0.62 V/decade for passivated TFTs. In addition, excellent water vapor transmission was observed for electron beam-irradiated Al2O3/TiO2-passivated poly(ether sulfone) substrates in a humidity test, because the Al2O3/TiO2 passivation layer can enhance the interface properties between Al2O3 and TiO2. To investigate the origin of this enhancement, we performed x-ray photoelectron spectroscopy of both unpassivated and Al2O3/TiO2-passivated TFTs with a-ZTO back-channel layers after Ar annealing.

  16. Wet Etching of Amorphous TiO2 Thin Films Using H3PO4-H2O2 Aqueous Solution

    Science.gov (United States)

    Okazaki, Sohei; Ohhashi, Takuya; Nakao, Shoichiro; Hirose, Yasushi; Hitosugi, Taro; Hasegawa, Tetsuya

    2013-09-01

    We report on the wet etching of amorphous undoped and Nb-doped TiO2 thin films using H3PO4-H2O2 etching solution. The etching rate (R) showed a maximum at a H3PO4 concentration of approximately 50 wt % at 80 °C, suggesting that H2PO4- and/or H3O+ is responsible for the etching reaction. The addition of H2O2 to H3PO4 solution significantly enhanced R, and an optimized solution exhibited an R of 13 nm/min at 80 °C, which is one order of magnitude higher than that using H2SO4. These results demonstrate that H3PO4-H2O2 aqueous solution is an effective etchant for TiO2-based amorphous thin films.

  17. Optimizing preparation of the TiO2 thin film reactor using the Taguchi method

    International Nuclear Information System (INIS)

    In this study, titanium dioxide thin film was prepared using the modified chemical vapor deposition. The parameters employed to control the preparation of the catalyst include the temperature of water bath, the Ti(OC3H7)4/H2O ratio, the flow rate of carrier gas, the oxidation temperature, the oxidation time, the calcination temperature, the rotating speed of furnace, and the speed of geared motor. The orthogonal arrays in the design of experimental method proposed by Taguchi were adopted to conduct the multiple-factor experiment. The conversion rate of salicylic acid in the aqueous or heterogeneous phase photocatalysis experiment was employed to identify the optimal conditions for assembly. The results indicated that a higher conversion ratio of the organic substance could be achieved under catalytic oxidation temperature of 400 oC, calcination temperature of 550 oC, and spraying speed of 30 rpm and the optimal experimental conditions obtained in this study were irradiation with intensity of 2.9 mW cm-2 on salicylic acid at concentration of 250 mg L-1 by both agitation and aeration processes (dissolved oxygen level = 8.2 mg O2 L-1) at pH 5, which could achieve optimal hydroxyl radical yield of 5.1 x 10-17 M.

  18. Fabrication of TiO2/EP super-hydrophobic thin film on filter paper surface.

    Science.gov (United States)

    Gao, Zhengxin; Zhai, Xianglin; Liu, Feng; Zhang, Ming; Zang, Deli; Wang, Chengyu

    2015-09-01

    A composite filter paper with super-hydrophobicity was obtained by adhering micro/nano structure of amorphous titanium dioxide on the filter paper surface with modifying low surface energy material. By virtue of the coupling agent, which plays an important part in bonding amorphous titanium dioxide and epoxy resin, the structure of super-hydrophobic thin film on the filter paper surface is extremely stable. The microstructure of super-hydrophobic filter paper was characterized by scanning electron microscopy (SEM), the images showed that the as-prepared filter paper was covered with uniform amorphous titanium dioxide particles, generating a roughness structure on the filter paper surface. The super-hydrophobic performance of the filter paper was characterized by water contact angle measurements. The observations showed that the wettability of filter paper samples transformed from super-hydrophilicity to super-hydrophobicity with the water contact angle of 153 ± 1°. Some experiments were also designed to test the effect of water-oil separation and UV-resistant by the super-hydrophobic filter paper. The prepared super-hydrophobic filter paper worked efficiently and simply in water-oil separation as well as enduringly in anti-UV property after the experiments. This method offers an opportunity to the practical applications of the super-hydrophobic filter paper. PMID:26005136

  19. Effect of deposition methods on the properties of photocatalytic TiO2 thin films prepared by spray pyrolysis and magnetron sputtering

    International Nuclear Information System (INIS)

    Titanium dioxide thin films were deposited by DC reactive magnetron sputtering and spray pyrolysis methods onto glass and glass coated with fluorine doped tin oxide (FTO). The films were characterized by x-ray diffraction, scanning electron microscopy, atomic force microscopy and UV-visible spectroscopy. For films deposited by the sputtering technique we have studied the effect of the total pressure of an Ar-O2 mixture on the substrate properties, on the deposition rate, phase composition, crystallinity, surface morphology and on the photocatalytic properties. Also transparent TiO2 thin films have been prepared by spray pyrolysis using a low concentration of titanium precursor with different substrate temperatures. At higher substrate temperatures the films were polycrystalline in the anatase phase; at lower substrate temperatures the films presented an amorphous configuration. The photocatalytic properties of TiO2 thin films were tested with the degradation methylene blue under UV light irradiation. The higher degradation rates were reached for films prepared by spray pyrolysis with a substrate temperature close to 400 deg. C, and for a high total pressure (16 mTorr) for films deposited by DC magnetron sputtering

  20. Effect of Calcination Temperature on Surface Morphology and Photocatalytic Activity in TiO2 Thin Film Prepared by Spin Coating Technique

    Directory of Open Access Journals (Sweden)

    Krishna Mohan Mothi

    2014-10-01

    Full Text Available TiO2 thin films were deposited on glass substrate using Sol-Gel derived precursor by Spin Coating technique at different calcination temperatures. Structural identity of the prepared films was con- firmed by powder X-ray diffraction measurements. Morphology of the films was monitored using Atomic force microscopy and it was observed that calcination temperature of 400 °C favored TiO2 nano- fibers. Photocatalytic activity of the films was checked by observing the degradation of herbicide Atrazine in UV region and the percentage of degradation was analyzed by HPLC method. © 2014 BCREC UNDIP. All rights reservedReceived: 21st November 2013; Revised: 18th March 2014; Accepted: 29th June 2014How to Cite: Mothi, K.M., Soumya, G., Sugunan, S. (2014. Effect of Calcination Temperature on Surface Morphology and Photocatalytic Activity in TiO2 Thin Films Prepared by Spin Coating Technique. Bulletin of Chemical Reaction Engineering & Catalysis, 9 (3: 175-181. (doi:10.9767/bcrec.9.3.5733.175-181Permalink/DOI: http://dx.doi.org/10.9767/bcrec.9.3.5733.175-181

  1. On the optical properties of Ag+15 ion beam irradiated TiO2 and SnO2 thin films

    CERN Document Server

    Thakur, Hardeep; Thakur, P; Sharma, K K; Singh, Abhinav Pratap; Kumar, Yogesh; Kumar, Ravi; Chae, Keun Hwa

    2011-01-01

    In this study, the effects of 200 MeV Ag+15 ion irradiation on the optical properties of TiO2 and SnO2 thin films prepared by RF magnetron sputtering technique were investigated. These films were characterized by the UV-vis spectroscopy and it was observed that with increase in irradiation fluence the transmittance for the TiO2 films systematically increases while that for SnO2 decreases. Absorption spectra of the irradiated samples showed a minor changes in indirect bandgap from 3.44 to 3.59 eV for TiO2 while that for SnO2 significant modifications in the direct bandgap from 3.92 to 3.6 eV were observed on increasing irradiation fluence. The observed modifications in the optical properties of both TiO2 and SnO2 systems with irradiation can be attributed to controlled structural disorder/defects in the system.

  2. On the optical properties of Ag+15 ion-beam-irradiated TiO2 and SnO2 thin films

    International Nuclear Information System (INIS)

    The effects of 200-MeV Ag+15 ion irradiation on the optical properties of TiO2 and SnO2 thin films prepared by using the RF magnetron sputtering technique were investigated. These films were characterized by using UV-vis spectroscopy, and with increasing irradiation fluence, the transmittance for the TiO2 films was observed to increase systematically while that for SnO2 was observed to decrease. Absorption spectra of the irradiated samples showed minor changes in the indirect bandgap from 3.44 to 3.59 eV with increasing irradiation fluence for TiO2 while significant changes in the direct bandgap from 3.92 to 3.6 eV were observed for SnO2. The observed modifications in the optical properties of both the TiO2 and the SnO2 systems with irradiation can be attributed to controlled structural disorder/defects in the system.

  3. Synthesis of TiO2 nanotube array thin films and determination of the optical constants using transmittance data

    Science.gov (United States)

    Ahmadi, K.; Abdolahzadeh Ziabari, Ali; Mirabbaszadeh, K.; Ahmadi, S.

    2015-01-01

    TiO2 nanotube arrays were grown on glass substrate by ZnO nanorod sol-gel template process. XRD analysis and FESEM microscopy were employed to characterize the structural and morphological properties of the prepared nanotube. EDX and UV-Vis spectroscopy were used to assess the chemical composition and study the optical properties of the film. An optical model has been performed to simulate the optical constants and thicknesses of the films from transmittance data using the Levenberg-Marquardt algorithm via Drude model. The simulated transmittance is in good agreement with the measured spectrum in the whole measurement wavelength range. The refractive index and extinction coefficient, thickness and dielectric function of TiO2 nanotube films were calculated by Drude model. Also, the related absorption coefficient, optical bandgap and porosity were determined.

  4. Processing, characterization and photocatalytic properties of Cu doped TiO2 thin films on glass substrate by sol-gel technique

    International Nuclear Information System (INIS)

    The present paper describes processing, properties and photocatalytic application of Cu doped TiO2 thin films on glass substrate. Cu doped TiO2 coatings were successfully prepared on glass slide substrates using sol-gel method. The obtained solutions exhibit acidic characteristics. The phase structure, thermal, microstructure and surface properties of the coatings were characterized by using XRD, DTA/TG, SEM and AFM. Their adhesion properties and spectroscopic analysis were investigated by a scratch tester and UV-vis spectroscopy. Four different solutions were prepared by changing Cu/Ti ratios. Glass substrates were coated by solutions of Ti-alkoxide, Cu-chloride, glacial acetic acid and isopropanol. The obtained gel films were dried at 300 deg. C for 10 min and subsequently heat-treated at 500 deg. C for 5 min in air. The oxide thin films were annealed at 600 deg. C for 60 min in air. TiO2, CuO, Cu4Ti, Ti3O5 and Cu3TiO4 phases were found in the coating. The organic matters were burned at temperatures between 200 and 350 deg. C and TiO2 crystallization was formed at 450 deg. C. The weight loss of the powder during process up to 600 deg. C is approximately 70%. The microstructural observations demonstrated that CuO content was led an improved surface morphology while thickness of the film and surface defects were increased in accordance with number of dipping. According trdance with number of dipping. According to AFM results, it was found that as the Cu/Ti content increases the surface roughness of the films increases. In addition structural, thermal and microstructural results, it was found that the films of 0.73 ratio have better adhesion strength to the glass substrate among other coatings. The oxide films were found to be active for photocatalytic decomposition of metylene blue

  5. Raman spectroscopy of dip-coated and spin-coated sol-gel TiO2 thin films on different types of glass substrates.

    Czech Academy of Sciences Publication Activity Database

    Kment, Š.; Gregora, Ivan; Kmentová, Hana; Novotná, P.; Hubi?ka, Zden?k; Krýsa, J.; Sajdl, P.; Dejneka, Alexandr; Brunclíková, M.; Jastrabík, Lubomír; Hrabovský, M.

    2012-01-01

    Ro?. 63, ?. 3 (2012), s. 294-306. ISSN 0928-0707 R&D Projects: GA ?R GAP108/12/1941; GA ?R GAP108/12/2104; GA TA ?R TA01010517 Institutional support: RVO:68378271 ; RVO:67985858 Keywords : TiO 2 thin films * Raman mapping * sol-gel * dip-coating * spin-coating * glass substrate Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.660, year: 2012

  6. TiO2 Thin Films Prepared by using Supercritical and Pressurized Fluids: The Effect of Various Extraction Conditions on Micro/Structural Properties of Thin Films.

    Czech Academy of Sciences Publication Activity Database

    Mat?jová, Lenka; Sajfrtová, Marie; Mat?j, Z.; Fajgar, Radek

    Marseille : International Society for Advancement of Supercritical Fluids, 2014, s. 161. ISBN 978-2-37111-002-1. [European Meeting on Supercritical Fluids /14./. Marseille (FR), 18.05.2014-21.05.2014] R&D Projects: GA ?R GA14-23274S Institutional support: RVO:67985858 Keywords : TiO2 * thin layers * supercritical fluids Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  7. Antifungal activity of Ag:hydroxyapatite thin films synthesized by pulsed laser deposition on Ti and Ti modified by TiO2 nanotubes substrates

    Science.gov (United States)

    Erakovi?, S.; Jankovi?, A.; Ristoscu, C.; Duta, L.; Serban, N.; Visan, A.; Mihailescu, I. N.; Stan, G. E.; Socol, M.; Iordache, O.; Dumitrescu, I.; Luculescu, C. R.; Jana?kovi?, Dj.; Miškovic-Stankovi?, V.

    2014-02-01

    Hydroxyapatite (HA) is a widely used biomaterial for implant thin films, largely recognized for its excellent capability to chemically bond to hard tissue inducing the osteogenesis without immune response from human tissues. Nowadays, intense research efforts are focused on development of antimicrobial HA doped thin films. In particular, HA doped with Ag (Ag:HA) is expected to inhibit the attachment of microbes and contamination of metallic implant surface. We herewith report on nano-sized HA and Ag:HA thin films synthesized by pulsed laser deposition on pure Ti and Ti modified with 100 nm diameter TiO2 nanotubes (fabricated by anodization of Ti plates) substrates. The HA-based thin films were characterized by SEM, AFM, EDS, FTIR, and XRD. The cytotoxic activity was tested with HEp2 cells against controls. The antifungal efficiency of the deposited layers was tested against the Candida albicans and Aspergillus niger strains. The Ti substrates modified with TiO2 nanotubes covered with Ag:HA thin films showed the highest antifungal activity.

  8. Highly antibacterial activity of N-doped TiO2 thin films coated on stainless steel brackets under visible light irradiation

    International Nuclear Information System (INIS)

    In this study, the radio frequency (RF) magnetron sputtering method was used to prepare a TiO2 thin film on the surface of stainless steel brackets. Eighteen groups of samples were made according to the experimental parameters. The crystal structure and surface morphology were characterized by X-ray diffraction, and scanning electron microscopy, respectively. The photocatalytic properties under visible light irradiation were evaluated by measuring the degradation ratio of methylene blue. The sputtering temperature was set at 300 °C, and the time was set as 180 min, the ratio of Ar to N was 30:1, and annealing temperature was set at 450 °C. The thin films made under these parameters had the highest visible light photocatalytic activity of all the combinations of parameters tested. Antibacterial activities of the selected thin films were also tested against Lactobacillus acidophilus and Candida albicans. The results demonstrated the thin film prepared under the parameters above showed the highest antibacterial activity.

  9. Highly antibacterial activity of N-doped TiO2 thin films coated on stainless steel brackets under visible light irradiation

    Science.gov (United States)

    Cao, Shuai; Liu, Bo; Fan, Lingying; Yue, Ziqi; Liu, Bin; Cao, Baocheng

    2014-08-01

    In this study, the radio frequency (RF) magnetron sputtering method was used to prepare a TiO2 thin film on the surface of stainless steel brackets. Eighteen groups of samples were made according to the experimental parameters. The crystal structure and surface morphology were characterized by X-ray diffraction, and scanning electron microscopy, respectively. The photocatalytic properties under visible light irradiation were evaluated by measuring the degradation ratio of methylene blue. The sputtering temperature was set at 300 °C, and the time was set as 180 min, the ratio of Ar to N was 30:1, and annealing temperature was set at 450 °C. The thin films made under these parameters had the highest visible light photocatalytic activity of all the combinations of parameters tested. Antibacterial activities of the selected thin films were also tested against Lactobacillus acidophilus and Candida albicans. The results demonstrated the thin film prepared under the parameters above showed the highest antibacterial activity.

  10. Microstructure characterization of sol-gel prepared MoO3-TiO2 thin films for oxygen gas sensors

    International Nuclear Information System (INIS)

    Binary metal-oxide MoO3-TiO2 films have been prepared using the sol-gel technique. The thin films were annealed at several temperatures including 400, 450, 500, 550, and 600 deg. C for 1 h. The morphology, crystalline structure, and chemical composition of the films have been analyzed using scanning electron microscopy (SEM) and atomic force microscopy, x-ray diffraction (XRD), Rutherford backscattering spectroscopy (RBS), and x-ray photoelectron spectroscopy (XPS) techniques. The SEM analysis showed that there are two different sizes of grains in the films annealed at temperatures of 400, 450, 500, and 550 deg. C. One grain type is small with 20-100 nm; the other is a large grain type several micrometers in length. The XRD analysis revealed that the films annealed at 400 deg. C were a mixture of orthorhombic and hexagonal MoO3 phases. The films annealed at 450 deg. C showed an increase in the hexagonal phase. A preferential orientation growth along the (100) plane of the hexagonal phase and the (010) plane of the orthorhombic phase has been found in both samples. RBS and XPS analysis showed that the films were stoichiometric. When the annealing temperature was increased beyond 500 deg. C, the concentration ratio of MoO3-TiO2 decreased due to the evaporation of MoO3. For the study of the electrical and gas sensing properties, the films were deposited on sapphire substrates with interdigital electrodes o substrates with interdigital electrodes on the frontside and a Pt heater on the backside. The MoO3-TiO2 thin films are sensitive to oxygen gas. The film has exhibited the O2 response (S=Rg/Rb) of 2.1, 8.1, and 80 for 120, 1000, and 10 000 ppm concentration of O2, respectively

  11. Synthesis and characterization of C-doped TiO2 thin films for visible-light-induced photocatalytic degradation of methyl orange

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • C-TiO2 thin films were successfully synthesized by modified sol–gel method based on the self-assembly technique. • Tween 80, one kind of hydrocarbon surfactants, was used as template and carbon precursor. • A thorough material characterization was performed to determine the effect of calcination time on the structural and optical properties of the synthesized catalyst films. - Abstract: C-TiO2 thin films were synthesized by a modified sol–gel route based on the self-assembly technique exploiting Tween80 (T80) as a pore directing agent and carbon source. The effect of calcination time on the photocatalytic activity of C-doped TiO2 catalyst was studied. The samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transforms infrared (FTIR), UV–vis diffuse reflectance spectroscopy, and photoluminescence spectra (PL). The XRD results showed that C-TiO2 sample calcined at 400 °C for various times exhibited anatase phase and no other crystal phase was identified. C-TiO2 exhibited a shift in an absorption edge of samples in the visible region than that of conventional or reference TiO2. The XPS results showed an existence of C in the TiO2 catalysts and C might be existed as C-O-Ti group. Moreover, the C-TiO2 thin film calcined at 400 °C for 30 min showed the lowest PL intensity due to a decrease in the recombination rate of photogenerated electrons and holes under UV light irradiation. Also the photocatalytic activity of synthesized catalyst was evaluated by decomposition of methyl orange (MO) under visible light irradiation. The results showed that the optimum preparations of C-TiO2 thin films were found to be under calcination temperature of 400, calcination time of 30 min, and with preparation 9 layers film

  12. Low temperature growth study of nano-crystalline TiO2 thin films deposited by RF sputtering

    Science.gov (United States)

    Safeen, K.; Micheli, V.; Bartali, R.; Gottardi, G.; Laidani, N.

    2015-07-01

    Precise control of the various structural phases of TiO2 at a low temperature is particularly important for practical applications. In this work, the deposition conditions for the growth of anatase and rutile phase at a low temperature (?300?°C) were optimized. TiO2 films were deposited by radio frequency (RF) sputtering of a ceramic TiO2 target in argon and argon-oxygen plasma (10 and 20% O2) at room temperature. For the films deposited in pure Ar and 20% O2, the growth temperature was varied from 25 to 400?°C. The plasma properties were investigated using optical emission spectroscopy (OES) in a wide range of values of gas composition (0–50% O2 in Ar-O2 mixture). The structural and chemical properties were characterized by means of x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS). The results indicate that O2 addition to the Ar-O2 gas mixture significantly changed the density of the plasma species (Ar, Ar+, Ti, Ti+ and O), which in turn influence the crystal structure and surface chemistry of the prepared films. Anatase phase was obtained for the films grown in Ar-O2 plasma over the whole range of temperature. In contrast, the films deposited in argon discharge largely persist in amorphous phase at temperature??200?°C and revealed the formation of single rutile phase at??300?°C. The oxygen vacancies detected by XPS analysis for the films deposited in Ar plasma facilitate the growth of a rutile phase at low temperature (?300?°C). Our results demonstrate that oxygen negative ions, oxygen vacancies and surface energy conditions at the substrate are the key parameters controlling the phase of the prepared films at low temperature.

  13. Templated synthesis of porous TiO2 thin films using amphiphilic graft copolymer and their use in dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Porous TiO2 thin films have been prepared using an amphiphilic graft copolymer, i.e. poly(vinylidene fluoride-co-chlorotrifluoroethylene)-graft-poly(oxyethylene methacrylate) (P(VDF-co-CTFE)-g-POEM) as a structure-directing agent via the sol-gel process. The graft copolymer was synthesized via atom transfer radical polymerization using CTFE units as an initiating site and designed to have a hydrophobic P(VDF-co-CTFE) domain and a hydrophilic POEM domain. Fourier transform-infra red spectroscopy indicated that a hydrophilic titania precursor was selectively incorporated into hydrophilic POEM domains. In-situ formation and morphologies of porous TiO2 thin films were confirmed by ultraviolet-visible spectroscopy, X-ray diffraction, transmission electron microscopy and thermogravimetric analysis. The resultant porous TiO2 films with 10-25 nm in size were used as a photoelectrode for solid-state dye-sensitized solar cells, exhibiting energy conversion efficiency of 2.8% at 100 mW/cm2.

  14. Photo-assisted electrochemical copper removal from cyanide solutions using porous TiO2 thin film photo-anodes

    Scientific Electronic Library Online (English)

    Álvaro A., Ramírez-Santos; Próspero, Acevedo-Peña; Elcy M., Córdoba.

    2014-02-01

    Full Text Available TiO2 porous films were prepared on ITO coated glass slides by the sol-gel dip-coating method assisted with Polyethylene glycol (PEG). The films were used as photo-anodes in the photo-assisted electrolytic removal of cuprous ions in cyanide media. These were characterized by SEM, UV-Visible spectrosc [...] opy and XRD. The PEG modified films were free of cracks and developed a porous structure after heat treatment at 500 ºC, due to the thermal decomposition of the structure associated PEG. It was demonstrated that the photo-assisted electrochemical reduction of copper is promoted by the use of modified TiO2 films as photo-anodes, thanks to the greater surface area given by the PEG decomposition. However, the film thickness was found to be a critical factor in the process, to such an extent that films composed of 5 layers were completely inefficient, meaning that despite the open porosity, multilayered films acted as a barrier within the photo-electrolytic process.

  15. Understanding of gas phase deposition of reactive magnetron sputtered TiO2 thin films and its correlation with bactericidal efficiency

    International Nuclear Information System (INIS)

    Highlights: ? Influence of O2 flow rates on the gas phase plasma during TiO2 film deposition was studied. ? The plasma parameters were determined and correlated with the film properties. ? O2 flow rate affects crystallinity, surface bonding, hydrophilicity, band gap and particle size of TiO2 films. ? These were found to be decisive factors for antibacterial property. ? These were found to be decisive factors for antibacterial property. - Abstract: Nanostructured TiO2 thin films were deposited using RF reactive magnetron sputtering at different O2 flow rates (20, 30, 50 and 60 sccm) and constant RF power of 200 W. In situ investigation of the nucleation and growth of the films was made by Optical Emission Spectroscopy (OES). The nano amorphous nature as revealed from X-ray diffraction (XRD) of the as deposited films and abundance of the Ti3+ surface oxidation states and surface hydroxyl group (OH?) in the films deposited at 50 sccm as determined from X-ray photo electron spectroscopy (XPS) was explained on the basis of emission spectra studies. The increase in band gap and decrease in particle size with O2 flow rate was observed from transmission spectra of UV–vis spectroscopy. Photoinduced hydrophilicity has been studied using Optical Contact Angle (OCA) measurement. The post irradiated films showed improved hydrophilicity. The bactericidal efficiency of thactericidal efficiency of these films was investigated taking Escherichia coli as model bacteria. The films deposited at 50 sccm shows better bactericidal activity as revealed from the optical density (OD) measurement. The qualitative analysis of the bactericidal efficiency was depicted from Scanning Electron Microscope images. A correlation between bactericidal efficiency and the deposited film has been established and explained on the basis of nucleation growth, band gap and hydrophilicity of the films.

  16. Photocatalytic performance of Sn-doped and undoped TiO2 nanostructured thin films under UV and vis-lights

    International Nuclear Information System (INIS)

    Sn-doped and undoped nano-TiO2 particles have been synthesized by hydrotermal process without solvent at 200 deg. C in 1 h. Nanostructure-TiO2 based thin films have been prepared on glass substrate by spin-coating technique. The structure, surface morphology and optical properties of the thin films and the particles have been investigated by element analysis and XRD, SEM, BET and UV-vis-NIR techniques. The photocatalytic performance of the films were tested for degradation of Malachite Green dye in solution under UV and vis-lights. The results showed that (a) hydrothermally synthesized nano-TiO2 particles are fully anatase crystalline form and are easily dispersed in water, (b) the coated surfaces have nearly super-hydrophilic properties and (c) the doping of transition metal ion efficiently improved the photocatalytic performance of the TiO2 thin film

  17. TiO2 and Al2O3 ultra thin nanolaminates growth by ALD; instrument automation and films characterization

    Directory of Open Access Journals (Sweden)

    H. Tiznado

    2012-01-01

    Full Text Available We report on the development of a fully operational atomic layer deposition (ALD system. This system is computer controlled and can deposit multilayered systems without user intervention. We describe the design of manifold, reaction chamber and exhaust. Additionally we give some features of the automatization software and electronics. To evaluate the ALD performance we used as precursor trymethyl aluminum (TMA and tetrakis (dimethylamino titanium (TDMAT to deposit Al2O3 and TiO2, respectively, in nanolaminated film structures. The thicknesses and composition of the films are precisely controlled, as determined by spectroscopic ellipsometry, and the nanolaminates have a sharp interface as indicated by Auger depth profile.

  18. Photocatalytic properties of different TiO2 thin films of various porosity and titania loading.

    Czech Academy of Sciences Publication Activity Database

    Zita, J.; Krýsa, J.; ?ernigoj, U.; Lavren?i?-Štangar, U.; Jirkovský, Jaromír; Rathouský, Ji?í

    2011-01-01

    Ro?. 161, ?. 1 (2011), s. 29-34. ISSN 0920-5861 R&D Projects: GA MŠk 1M0577; GA ?R GA104/08/0435 Institutional research plan: CEZ:AV0Z40400503 Keywords : sol-gel * titanium dioxide film * porosity Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.407, year: 2011

  19. Brookite TiO2 thin film epitaxially grown on (110) YSZ substrate by atomic layer deposition.

    Science.gov (United States)

    Kim, Dai-Hong; Kim, Won-Sik; Kim, Sungtae; Hong, Seong-Hyeon

    2014-08-13

    Epitaxial brookite TiO2 (B-TiO2) film was deposited on (110) yttria-stabilized zirconia (YSZ) substrate using plasma-enhanced atomic layer deposition, and its structural, optical, and gas sensing properties were investigated. As-deposited TiO2 film was a pure brookite and (120) oriented. The determined in-plane orientation relationships were [21?0]B-TiO2//[1?10]YSZ and [001]B-TiO2 //[001]YSZ. The B-TiO2 film showed ?70% transmittance and the optical band gap energy was 3.29 eV. The B-TiO2 film-based gas sensor responded to H2 gas even at room temperature and the highest magnitude of the gas response was determined to be ?150 toward 1000 ppm of H2/air at 150 °C. In addition, B-TiO2 sensor showed a high selectivity for H2 against CO, EtOH, and NH3. PMID:25007217

  20. Morphological Modification of TiO2 Thin Films as Highly Efficient Photoanodes for Photoelectrochemical Water Splitting.

    Science.gov (United States)

    Ibadurrohman, Muhammad; Hellgardt, Klaus

    2015-05-01

    TiO2 films with modified morphology have been successfully synthesized via a facile spray-pyrolysis method in the presence of poly(ethylene glycol) (PEG) as a templating agent. The effects of the PEG concentration on the relevant properties of TiO2 films were investigated by means of scanning electron microscopy, X-ray diffraction, and UV-vis absorbance spectroscopy, while their photocatalytic properties were assessed by photoelectrochemical (PEC) water-splitting measurements. The introduction of 10 g·L(-1) PEG into the precursor solution leads to surface roughening with an exceptional improvement in PEC responses, revealing a photoconversion efficiency of 1.15% at -0.50 V vs HgO|Hg (in a 1 M NaOH electrolyte under broad-spectrum illumination), which is nearly triple that of the unmodified film (0.45% at -0.38 V vs HgO|Hg). Although the efficiency of the rough-surface photoanodes deteriorates upon increasing the PEG content, their PEC responses are still superior to those of smooth-surface films. Possible phenomena that might be responsible for the experimental observations are suggested and discussed accordingly. PMID:25902420

  1. Photocatalytic performance of Sn-doped TiO2 nanostructured thin films for photocatalytic degradation of malachite green dye under UV and VIS-lights

    International Nuclear Information System (INIS)

    Sn-doped and undoped nano-TiO2 particles have been synthesized by hydrotermal process without acid catalyst at 225 deg. C in 1 h. Nanostructure-TiO2 based thin films, contain at different solid ratio of TiO2 in coating, have been prepared on glass surfaces by spin-coating technique. The structure, surface morphology and optical properties of the thin films and the particles have been investigated by element analysis and XRD, BET and UV/VIS/NIR techniques. The photocatalytic performance of the films was tested for degradation of malachite green dye in solution under UV and VIS-lights. The results showed that the hydrothermally synthesized nano-TiO2 particles are fully anatase crystalline form and are easily dispersed in water, the coated surfaces have nearly super-hydrophilic properties and, the doping of transition metal ion efficiently improved the photocatalytic performance of the TiO2 thin film. The results also proved that malachite green is decomposed catalytically due to the pseudo first-order reaction kinetics

  2. Atomic layer deposition, characterization, and growth mechanistic studies of TiO2 thin films.

    Science.gov (United States)

    Kaipio, Mikko; Blanquart, Timothee; Tomczak, Yoann; Niinistö, Jaakko; Gavagnin, Marco; Longo, Valentino; Wanzenböck, Heinz D; Pallem, Venkateswara R; Dussarrat, Christian; Puukilainen, Esa; Ritala, Mikko; Leskelä, Markku

    2014-07-01

    Two heteroleptic titanium precursors were investigated for the atomic layer deposition (ALD) of titanium dioxide using ozone as the oxygen source. The precursors, titanium (N,N'-diisopropylacetamidinate)tris(isopropoxide) (Ti(O(i)Pr)3(N(i)Pr-Me-amd)) and titanium bis(dimethylamide)bis(isopropoxide) (Ti(NMe2)2(O(i)Pr)2), exhibit self-limiting growth behavior up to a maximum temperature of 325 °C. Ti(NMe2)2(O(i)Pr)2 displays an excellent growth rate of 0.9 Å/cycle at 325 °C while the growth rate of Ti(O(i)Pr)3(N(i)Pr-Me-amd) is 0.3 Å/cycle at the same temperature. In the temperature range of 275-325 °C, both precursors deposit titanium dioxide in the anatase phase. In the case of Ti(NMe2)2(O(i)Pr)2, high-temperature X-ray diffraction (HTXRD) studies reveal a thickness-dependent phase change from anatase to rutile at 875-975 °C. X-ray photoelectron spectroscopy (XPS) indicates that the films have high purity and are close to the stoichiometric composition. Reaction mechanisms taking place during the ALD process were studied in situ with quadrupole mass spectrometry (QMS) and quartz crystal microbalance (QCM). PMID:24896967

  3. Facile solution-controlled growth of CuInS2 thin films on FTO and TiO2/FTO glass substrates for photovoltaic application

    International Nuclear Information System (INIS)

    This paper reports on the preparation of two thin films (CuInS2/FTO and CuInS2/TiO2/FTO) by a facile solvothermal method and their photovoltaic properties. Instrumental measurements including X-ray diffraction (XRD), inductively coupled plasma emission spectroscopy (ICP), scanning electron microscopy (SEM), and UV-vis spectra have been used to characterize the obtained CuInS2 thin films. The results show that the CuInS2 films deposited on fluorine-doped tin oxide-coated (FTO) conductive glass substrates are composed of nanoplates and microspheres. The thickness of the CuInS2/FTO films can be adjusted from 1 ?m to 8 ?m by controlling the solution concentration of the reactants. While, the prepared 10 ?m-thick CuInS2 film on the TiO2 film substrate consists of nanoplates. The UV-vis absorption spectra reveal that the CuInS2 thin films have a strong absorption around 400-850 nm and the band-gap energy is tunable in the range of 1.45-1.61 eV with the variation of Cu/In ratio from 1.20 to 0.90. Furthermore, two types of thin film solar cells, which have an effective area of 0.25 cm2 and possess separately the top-down composition of Ag/CdS/CuInS2/FTO and FTO/TiO2/CuInS2/Au, were fabricated after heat-treatment to evaluate their photovoltaic properties and the corresponding conversion efficiency is 0.33% and 0.29% under AM 1.5 irrncy is 0.33% and 0.29% under AM 1.5 irradiation (100 mW cm-2), respectively.

  4. Microstructure and optical dispersion characterization of nanocomposite sol-gel TiO2-SiO2 thin films with different compositions

    Science.gov (United States)

    Kermadi, S.; Agoudjil, N.; Sali, S.; Zougar, L.; Boumaour, M.; Broch, L.; En Naciri, A.; Placido, F.

    2015-06-01

    Nanocomposite TiO2-SiO2 thin films with different compositions (from 0 to 100 mol% TiO2) were deposited by sol-gel dip-coating method on silicon substrate. Crystal structure, chemical bonding configuration, composition and morphology evolutions with composition were followed by Raman scattering, Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy and scanning electron microscopy respectively. The refractive index and the extinction coefficient were derived in a broad band wavelength (250-900 nm) from spectroscopic ellipsometry data with high accuracy and correlated with composition and microstructure. Results showed an anatase structure for 100% TiO2 with a grain size in 6-10 nm range. Whereas, the inclusion of SiO2 enlarges the optical band gap and suppresses the grain growth up to 4 nm in size. High TiO2 dispersion in SiO2 matrix was observed for all mixed materials. The refractive index (at ? = 600 nm) increases linearly with composition from 1.48 (in 100% SiO2) to 2.22 (in 100% TiO2) leading to lower dense material, its dispersion being discussed in terms of the Wemple-DiDomenico single oscillator model. Hence, the optical parameters, such optical dispersion energies E0 and Ed, the average oscillators, strength S0 and wavelength ?0 and the ratio of the carrier concentration to the effective mass N/m? have been derived. The analysis revealed a strong dependence on composition and structure. The optical response was also investigated in term of complex optical conductivity (?) and both volume and surface energy loss functions (VELF and SELF).

  5. Microstructure and optical dispersion characterization of nanocomposite sol-gel TiO2-SiO2 thin films with different compositions.

    Science.gov (United States)

    Kermadi, S; Agoudjil, N; Sali, S; Zougar, L; Boumaour, M; Broch, L; En Naciri, A; Placido, F

    2015-06-15

    Nanocomposite TiO2-SiO2 thin films with different compositions (from 0 to 100mol% TiO2) were deposited by sol-gel dip-coating method on silicon substrate. Crystal structure, chemical bonding configuration, composition and morphology evolutions with composition were followed by Raman scattering, Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy and scanning electron microscopy respectively. The refractive index and the extinction coefficient were derived in a broad band wavelength (250-900nm) from spectroscopic ellipsometry data with high accuracy and correlated with composition and microstructure. Results showed an anatase structure for 100% TiO2 with a grain size in 6-10nm range. Whereas, the inclusion of SiO2 enlarges the optical band gap and suppresses the grain growth up to 4nm in size. High TiO2 dispersion in SiO2 matrix was observed for all mixed materials. The refractive index (at ?=600nm) increases linearly with composition from 1.48 (in 100% SiO2) to 2.22 (in 100% TiO2) leading to lower dense material, its dispersion being discussed in terms of the Wemple-DiDomenico single oscillator model. Hence, the optical parameters, such optical dispersion energies E0 and Ed, the average oscillators, strength S0 and wavelength ?0 and the ratio of the carrier concentration to the effective mass N/m(?) have been derived. The analysis revealed a strong dependence on composition and structure. The optical response was also investigated in term of complex optical conductivity (?) and both volume and surface energy loss functions (VELF and SELF). PMID:25770938

  6. Surface characterization of poly(methylmethacrylate) based nanocomposite thin films containing Al2O3 and TiO2 nanoparticles

    International Nuclear Information System (INIS)

    Poly(methylmethacrylate) (PMMA) based nanocomposite electron beam resists have been demonstrated by spin coating techniques. When TiO2 and Al2O3 nanoparticles were directly dispersed into the PMMA polymer matrix, the resulting nanocomposites produced poor quality films with surface roughnesses of 322 and 402 nm respectively. To improve the surface of the resists, the oxide nanoparticles were encapsulated in toluene and methanol. Using the zeta potential parameter, it was found that the stabilities of the toluene/oxide nanoparticle suspensions were 7.7 mV and 19.4 mV respectively, meaning that the suspension was not stable. However, when the TiO2 and Al2O3 nanoparticles were encapsulated in methanol the zeta potential parameter was 31.9 mV and 39.2 mV respectively. Therefore, the nanoparticle suspension was stable. This method improved the surface roughness of PMMA based nanocomposite thin films by a factor of 6.6 and 6.4, when TiO2 and Al2O3 were suspended in methanol before being dispersed into the PMMA polymer.

  7. Characterization of Cr-N codoped anatase TiO2(001) thin films epitaxially grown on SrTiO3(001) substrate

    Science.gov (United States)

    Wang, Yang; Cheng, Zhengwang; Tan, Shijing; Shao, Xiang; Wang, Bing; Hou, J. G.

    2013-10-01

    We investigate the growth of Cr-N codoped anatase TiO2(001) thin films, prepared with a pulsed-laser-deposition (PLD) method using a mixed Cr2O3 and TiN ceramic target (6 at.% Cr), and characterized using scanning tunneling microscopy (STM), X-ray and ultraviolet photoemission spectroscopy (XPS/UPS), and ultraviolet-visible (UV-Vis) absorption spectroscopy. We find that the doping concentration of N in the films can be finely tuned by the O2 pressure and the growth temperature. By optimizing the growth conditions, we obtain the anatase TiO2(001) films with relatively smooth (1 × 4) reconstructed surface at equally codoped contents of 6 at.% Cr and 6 at.% N. The roughness of the surface is about 0.9 nm in root mean square, and the typical size of the (1 × 4) terraces is about 20 nm. The XPS results indicate that Cr and N should be both substitutionally doped in the film. From the UPS spectrum for the codoped film, the valence band maximum is significantly lifted by about 1.3 eV, indicating a narrowing band gap of 1.9 eV. The optical absorption spectrum shows that the codoped film noticeably absorbs the light at less than 710 nm. Derived from the optical absorption spectrum, an estimated band gap value of 1.78 eV is obtained, which is consistent with the UPS result.

  8. Studies on the room temperature growth of nanoanatase phase TiO2 thin films by pulsed dc magnetron with oxygen as sputter gas

    International Nuclear Information System (INIS)

    The anatase phase titanium dioxide (TiO2) thin films were deposited at room temperature by pulsed dc magnetron sputtering using pure oxygen as sputter gas. The structural, optical, electrical, and electrochromic properties of the films have been studied as a function of oxygen pressure in the chamber. The x-ray diffraction results indicate that the films grown above 4.5x10-2 mbar are nanocrystalline (grain size of 28-43 nm) with anatase phase. The films deposited at the chamber pressure of 7.2x10-2 mbar are found to be highly crystalline with a direct optical band gap of 3.40 eV, refractive index of 2.54 (at ?=400 nm), and work function of 4.77 eV (determined by the Kelvin probe measurements). From the optical emission spectra of the plasma and transport of ions in matter calculations, we find that the crystallization of TiO2 at room temperature is due to the impingement of electrons and ions on the growing films. Particularly, the negative oxygen ions reflected from the target by 'negative ion effects' and the enhanced density of TiO, TiO+, TiO2+, and O2+ particles in the plasma are found to improve the crystallization even at a relatively low temperature. From an application point of view, the film grown at 7.2x10-2 mbar was studied for its electrochromic properties by protonic intercalation. It showed good electrochromic behavior with an optical modulation of ?45%,ior with an optical modulation of ?45%, coloration efficiency of 14.7 cm2 C-1, and switching time (tc) of 50 s for a 2x2 cm2 device at ?=633 nm

  9. Novel hydrophobic/hydrophilic patterning process by photocatalytic Ag nucleation on TiO 2 thin film and electroless Cu deposition

    Science.gov (United States)

    Nishimoto, Shunsuke; Kubo, Atsushi; Zhang, Xintong; Liu, Zhaoyue; Taneichi, Noriaki; Okui, Toshiki; Murakami, Taketoshi; Komine, Takashi; Fujishima, Akira

    2008-07-01

    A hydrophobic/super-hydrophilic pattern was prepared on a TiO 2 thin film by a new fabrication process. The process consists of five key steps: (1) photocatalytic reduction of Ag + to Ag (nucleation), (2) electroless Cu deposition, (3) oxidation of Cu to CuO, (4) deposition of a self-assembled monolayer (SAM), and (5) photocatalytic decomposition of selected areas of the SAM. A hydrophobic/super-hydrophilic pattern with 500-?m 2 hydrophilic areas was obtained in this process. It is particularly noteworthy that a UV irradiation time of only 1 s was sufficient for the nucleation step in the patterning process.

  10. TiO2 and Al2O3 ultra thin nanolaminates growth by ALD; instrument automation and films characterization

    Scientific Electronic Library Online (English)

    H., Tiznado; D., Domínguez; W. de la, Cruz; R., Machorro; M., Curiel; G., Soto.

    2012-12-01

    Full Text Available We report on the development of a fully operational atomic layer deposition (ALD) system. This system is computer-controlled and can deposit multilayered systems without user intervention. We describe the design of manifold, reaction chamber and exhaust. Additionally we give some features of the aut [...] omatization software and electronics. To evaluate the ALD performance we used as precursor trymethyl aluminum (TMA) and tetrakis (dimethylamino) titanium (TDMAT) to deposit Al2O3 and TiO2, respectively, in nanolaminated film structures. The thicknesses and composition of the films are precisely controlled, as determined by spectroscopic ellipsometry, and the nanolaminates have a sharp interface as indicated by Auger depth profile.

  11. Preparation and characterization of hydrophobic organic-inorganic composite thin films of PMMA/SiO2/TiO2 with low friction coefficient

    International Nuclear Information System (INIS)

    Organic-inorganic polymethacrylate (PMMA)/SiO2/TiO2 composite thin films with controlled thickness and hydrophobicity have been synthesized. The precursor solution of hybrid systems based on 3-trimethoxysilyl propyl methacrylate (TMSM), tetramethylorthosilicate (TMOS), methyl methacrylate (MMA), and tetrabutyl titanate (TBT) were prepared by sol-gel processes. The in situ derivatization of the precursor solution by perfluoroalkylsulfonyl alkyl triakoxy silane C8F17SO2NHC3H6Si(OCH3)3 (trade name: FC-922) effectively increases the hydrophobicity of the film with a contact angle for water of more than 100 deg. . The structure and properties of the hybrid composite thin film were investigated using TG/DTA, FT-IR, XRD, XPS, and AFM. The thickness of the thin film was less than 120 nm which was measured by cross-sectional scanning electron microscopy. The tribological behavior of the thin film was examined. The friction coefficient of the film prepared is very low (0.09-0.11), and the anti-wear behavior is good, with a lack of failure even after 8000 sliding passes. These films are meeting practical lubricant and protection process requirements, including low processing temperature, high thermal stability, and reliable mechanical properties

  12. Photocatalytic Antibacterial Performance of Glass Fibers Thin Film Coated with N-Doped SnO2/TiO2

    Science.gov (United States)

    Sikong, Lek; Niyomwas, Sutham; Rachpech, Vishnu

    2014-01-01

    Both N-doped and undoped thin films of 3SnO2/TiO2 composite were prepared, by sol-gel and dip-coating methods, and then calcined at 600°C for 2 hours. The films were characterized by FTIR, XRD, UV-Vis, SEM, and XPS, and their photocatalytic activities to degrade methylene blue in solution were determined, expecting these activities to correlate with the inactivation of bacteria, which was confirmed. The doped and undoped films were tested for activities against Gram-negative Escherichia coli (E. coli) and Salmonella typhi (S. typhi), and Gram-positive Staphylococcus aureus (S. aureus). The effects of doping on these composite films included reduced energy band gap, high crystallinity of anatase phase, and small crystallite size as well as increased photocatalytic activity and water disinfection efficiency. PMID:24693250

  13. Annealing of TiO2 Films Deposited on Si by Irradiating Nitrogen Ion Beams

    International Nuclear Information System (INIS)

    Thin TiO2 films were deposited on Si at a temperature of 600 deg. C by an ion beam assisted deposition (IBAD) method. The TiO2 films were annealed for 30 min in Ar at temperatures below 700 deg. C. The as-deposited TiO2 films had high permittivities such 200 ?o and consisted of crystallites that were not preferentially oriented to the c-axis but had an expanded c-axis. On the annealed TiO2 films, permittivities became lower with increasing annealing temperature, and crystallites were oriented preferentially to the (110) plane

  14. Derivation and Optical Properties of Co, Mn, Nd Doped SiOand SiO2-TiO2 Thin Films

    International Nuclear Information System (INIS)

    In this research, SiO2-TiO2 and Co, Mn, Nd doped SiO2 thin films were prepared by the sol-gel-dip coating method on glass substrates using Si(OC2H5)4 (TEOS, tetraethylorthosilicate) and Ti(OBu)4 (tetrabutylorthotitanate) as starting materials. Precursor solutions were prepared by dissolving Si(OC2H5)4 and Ti(OBu)4 in ethanol. Various layers of coatings were obtained at room temperature by sol-gel dip-coating process at a withdrawal speed of 10 mm/sec. The coated substrates were exposed to heat treatment at 650 degree. The effect of chemistry of the precursor solution on the microstructure and optical properties of the films were examined by UV-VIS, AFM (Atomic Force Microscopy) and SE (Spectroscopic Ellypsometry). Band gaps of the films were determined by using absoption spectrum

  15. Research on TiO2-Based Photocatalyst Thin Film and Its Application in a Pilot-Scale Supply Water Treatment System

    Directory of Open Access Journals (Sweden)

    The-Vinh Nguyen

    2009-01-01

    Full Text Available In order to utilize the abundant natural sunlight in Hochiminh City for energy-saving purpose, the application of TiO2-based photocatalyst thin film coated on ceramic beads in a pilot-scale supply water treatment system of 2 m3/day was studied in this present work. The photocatalyst thin film was prepared by sol-gel and spray coating methods. The derived photocatalyst thin film presented high BET specific surface area of more than 160 m2/g while it also maintained good crystallinity. These superior physicochemical properties of the photocatalyst were well consistent with its strong photoactivity in the pilot-scale supply water treatment system. Groundwater after passed through ferric removal and sandfilter systems was treated in the pilot-scale supply water treatment system using the photocatalyst thin film. The COD, TOC and coliform removal efficiencies were measured at 63%, 51% and 100%, respectively by using the above system under natural sunlight in Hochiminh City.

  16. DIRECT PHOTODEPOSITION OF NANOSTRUCTURED TIO2 THIN FILMS FROM B-DIKETONATE COMPLEXES, AND THEIR PHOTOCATALYTIC BEHAVIOUR

    Scientific Electronic Library Online (English)

    M, TEJOS; G.E., BUONO-CUORE; F.R., DÍAZ; M.A., DEL VALLE; J, PALOMARES.

    2004-12-01

    Full Text Available Amorphous Titania thin films have been photochemically obtained by direct UV irradiation (254 nm) of an amorphous TiO(C6H5COCHCOCH3) 2 film spin-coated on Si(100) and borosilicate glass. These materials were characterized by scanning electron microscopy (SEM), X-ray diffraction spectroscopy (XRD) an [...] d Auger electron spectroscopy (AES). SEM analysis showed a porous film with irregular morphology (diameter

  17. Modeling the electrical transport in epitaxial undoped and Ni-, Cr-, and W-doped TiO2 anatase thin films

    Science.gov (United States)

    Kneiß, Max; Jenderka, Marcus; Brachwitz, Kerstin; Lorenz, Michael; Grundmann, Marius

    2014-08-01

    Electrical transport in undoped and Ni-, Cr-, and W-doped TiO2 thin films on SrTiO3(001) is modelled either with the sum of two thermally activated processes with exponential temperature dependence of conductivity, or with the sum of three-dimensional Mott variable-range hopping (VRH) and an activated process with low activation energy. The latter is interpreted for both models as small polaron hopping (chi-square values, the double activated model is superior for data of higher ordered films grown at 540 and 460 °C. For lower growth temperature, VRH plus activated conductivity fits partly better. For all dopants, n-type conductivity is observed.

  18. Optical and structural properties of nanocrystalline anatase (TiO2) thin films prepared by non-aqueous sol-gel dip-coating

    International Nuclear Information System (INIS)

    Anatase (TiO2) thin films were grown by non-aqueous sol-gel dip-coating using titanium (IV) n-butoxide as precursor and 1-butanol as solvent. High withdrawal speed of 4.7 mm/s in dip-coating resulted in defect free films of 100 nm average film thickness after subsequent heat treatments. According to scanning electron microscope and X-ray diffraction measurements, the films consisted of nanocrystalline anatase with 30 nm mean crystallite size. Refractive index n(?) and extinction coefficient k(?) were determined over the wavelength range from 200 to 1650 nm. The optical band gap of the film material was approximately 3.2 eV. The results showed very similar optical characteristics to those that are accomplished with chemically more reactive aqueous sol-gel processes. Furthermore, it was found that in addition to porosity, coordination number of Ti atoms to nearest oxygen neighbors is likely to have a significant role in explaining differences of optical properties between bulk anatase and thin film materials of the present work.

  19. Anomalous C-V response correlated to relaxation processes in TiO2 thin film based-metal-insulator-metal capacitor: Effect of titanium and oxygen defects

    Science.gov (United States)

    Kahouli, A.; Marichy, C.; Sylvestre, A.; Pinna, N.

    2015-04-01

    Capacitance-voltage (C-V) and capacitance-frequency (C-f) measurements are performed on atomic layer deposited TiO2 thin films with top and bottom Au and Pt electrodes, respectively, over a large temperature and frequency range. A sharp capacitance peak/discontinuity (C-V anomalous) is observed in the C-V characteristics at various temperatures and voltages. It is demonstrated that this phenomenon is directly associated with oxygen vacancies. The C-V peak irreversibility and dissymmetry at the reversal dc voltage are attributed to difference between the Schottky contacts at the metal/TiO2 interfaces. Dielectric analyses reveal two relaxation processes with degeneration of the activation energy. The low trap level of 0.60-0.65 eV is associated with the first ionized oxygen vacancy at low temperature, while the deep trap level of 1.05 eV is associated to the second ionized oxygen vacancy at high temperature. The DC conductivity of the films exhibits a transition temperature at 200 °C, suggesting a transition from a conduction regime governed by ionized oxygen vacancies to one governed by interstitial Ti3+ ions. Both the C-V anomalous and relaxation processes in TiO2 arise from oxygen vacancies, while the conduction mechanism at high temperature is governed by interstitial titanium ions.

  20. The Effect of Tween® Surfactants in Sol-Gel Processing for the Production of TiO2 Thin Films

    Directory of Open Access Journals (Sweden)

    Ann-Louise Anderson

    2014-12-01

    Full Text Available Titanium dioxide thin films were deposited using a Tween® surfactant modified non-aqueous sol-gel method onto fluorine doped tin oxide glass substrates. The surfactant concentration and type in the sols was varied as well as the number of deposited layers. The as deposited thin films were annealed at 500 °C for 15 min before characterisation and photocatalytic testing with resazurin intelligent ink. The films were characterised using scanning electron microscopy, atomic force microscopy, X-ray diffraction, Raman spectroscopy and UV-Vis spectroscopy. Photocatalytic activity of the films was evaluated using a resazurin dye-ink test and the hydrophilicity of the films was analysed by water-contact angles measurements. Characterisation and photocatalytic testing has shown that the addition of surfactant in varying types and concentrations had a significant effect on the resulting thin film microstructure, such as changing the average particle size from 130 to 25 nm, and increasing the average root mean square roughness from 11 to 350 nm. Such structural changes have resulted in an enhanced photocatalytic performance for the thin films, with an observed reduction in dye half-life from 16.5 to three minutes.

  1. Evolution of structural and magnetic properties of Co-doped TiO2 thin films irradiated with 100 MeV Ag7+ ions

    International Nuclear Information System (INIS)

    In continuation to our earlier studies where we have shown room temperature ferromagnetism observed in TiO2 and Co-doped TiO2 (CTO) thin films independent of their phase (Mohanty et al 2012 J. Phys. D: Appl. Phys. 45 325301), here the modifications in structure and magnetic properties in CTO thin films using 100 MeV Ag7+ ion irradiation are reported. Owing to the important role of defects in tailoring the magnetic properties of the material, we vary the ion fluence from 5 × 1011 to 1 × 1012 ions cm?2 to create post-deposition defects. While the film deposited under 0.1 mTorr oxygen partial pressure retains its crystallinity showing radiation-resistant behaviour even at a fluence of 1 × 1012 ions cm?2, films deposited under 1 to 300 mTorr oxygen partial pressure becomes almost amorphous at the same fluence. Using Poisson's law, the diameter of the amorphized region surrounding the ion path is calculated to be ?4.2 nm from the x-ray diffraction peak intensity ((1?1?0) for rutile phase) as a function of ion fluence. The saturation magnetization (Ms) decreases exponentially similar to the decrease in x-ray peak intensity with fluence, indicating magnetic disordered region surrounding the ion path. The diameter of the magnetic disordered region is found to be ?6.6 nm which is larger than the diameter of the amorphized latent track. Therefore, it is confirmed that swift heavy ion irradiation induces a more significant magnetic disorder than the structural disorder. (paper)

  2. Photocatalytic degradation of methylorange Using TiO2, WO3 and mixed thin films under controlled pH and H2O2.

    Science.gov (United States)

    Carcel, Radu Adrian; Andronic, Luminita; Duta, Anca

    2011-10-01

    Wastewaters resulting from textile industry sector have a different chemistry compared with most of the other wastewaters. The different dyes in excess are usually very stable and even small quantities can have a major impact to the effluent. In order to treat these wastewaters, photodegradation is a largely investigated process that can be up-scaled. Photocatalysts based on wide band gap semiconductors can be used in heterogeneous photocatalysis and mostly reported are TiO2 and WO3. Under UV irradiation they form electron-hole pairs that produce active species that can oxidize the dye molecules. The electron-hole recombination represents the main cause for low efficiencies and is limited by the use of oxidant systems like H2O2. Doctor blade technique, a reproducible, up-scalable and low cost technique was used to obtain thin films. The reference dye, used in this experiment is methylorange in solution of 0.0125 mM, corresponding to average polluted water. In order to reduce the recombination in the catalysts, H2O2 is used. Another important aspect of the dye photocatalysis process, investigated in the paper is the adsorption of the dye molecule on the photocatalyst surface, strongly depending on pH which affects the dye's structure and the surface charge. Experiments are conducted at fixed pH values: 3, and respectively 7 covering values below and over the ZPC of the photocatalysts. The results show that TiO2/WO3 films have higher efficiency then the TiO2 and WO3 films, mainly due to the surface morphology of the films. By adding H2O2, higher efficiencies are obtained, confirming that the electron-hole pair recombination is reduced. From the point of view of pH, higher efficiencies are obtained in acidic solutions and the results are comparatively discussed considering the dye's ionic/neutral structure and the photocatalyst surface charge. The efficiency was calculated using UV-VIS spectrophotometer measurements of the solution and the thin films were characterized by AFM and XRD. PMID:22400308

  3. Tuning the Photocatalytic Activity of Anatase TiO2 Thin Films by Modifying the Preferred <001> Grain Orientation with Reactive DC Magnetron Sputtering

    Directory of Open Access Journals (Sweden)

    B. Stefanov

    2014-08-01

    Full Text Available Anatase TiO2 thin films were deposited by DC reactive magnetron sputtering on glass substrates at 20 mTorr pressure in a flow of an Ar and O2 gas mixture. The O2 partial pressure (PO2 was varied from 0.65 mTorr to 1.3 mTorr to obtain two sets of films with different stoichiometry. The structure and morphology of the films were characterized by secondary electron microscopy, atomic force microscopy, and grazing-angle X-ray diffraction complemented by Rietveld refinement. The as-deposited films were amorphous. Post-annealing in air for 1 h at 500 °C resulted in polycrystalline anatase film structures with mean grain size of 24.2 nm (PO2 = 0.65 mTorr and 22.1 nm (PO2 = 1.3 mTorr, respectively. The films sputtered at higher O2 pressure showed a preferential orientation in the <001> direction, which was associated with particle surfaces exposing highly reactive {001} facets. Films sputtered at lower O2 pressure exhibited no, or very little, preferential grain orientation, and were associated with random distribution of particles exposing mainly the thermodynamically favorable {101} surfaces. Photocatalytic degradation measurements using methylene blue dye showed that <001> oriented films exhibited approximately 30% higher reactivity. The measured intensity dependence of the degradation rate revealed that the UV-independent rate constant was 64% higher for the <001> oriented film compared to randomly oriented films. The reaction order was also found to be higher for <001> films compared to randomly oriented films, suggesting that the <001> oriented film exposes more reactive surface sites.

  4. Impact of water quality on removal of carbamazepine in natural waters by N-doped TiO2 photo-catalytic thin film surfaces

    International Nuclear Information System (INIS)

    Highlights: ? N-doped TiO2 thin films have been deposited by sol–gel dip-coating. ? CBZ removal improved with increasing medium pH in the range of 5–9. ? DOC at a concentration of 5 mg/L resulted in an ?20% reduction in CBZ removal. ? Alkalinity values of 100 mg/L as CaCO3 resulted in a 40% decrease in CBZ removal. ? Complete suppression of the photocatalytic process in wastewater effluent. -- Abstract: Photocatalytic experiments on the pharmaceutical pollutant carbamazepine (CBZ) were conducted using sol–gel nitrogen-doped TiO2-coated glass slides under a solar simulator. CBZ was stable to photodegradation under direct solar irradiation. No CBZ sorption to the catalyst surface was observed, as further confirmed by surface characterization using X-ray photoelectron spectroscopic analysis of N-doped TiO2 surfaces. When exposing the catalyst surface to natural organic matter (NOM), an excess amount of carbon was detected relative to controls, which is consistent with NOM remaining on the catalyst surface. The catalyst surface charge was negative at pH values from 4 to 10 and decreased with increasing pH, correlated with enhanced CBZ removal with increasing medium pH in the range of 5–9. A dissolved organic carbon concentration of 5 mg/L resulted in ?20% reduction in CBZ removal, probably due to competitive inhibition of the photocatalytic degradation of CBZ. At alkalinity values corresponding to CaCO3 addition at 100 mg/L, an over 40% decrease in CBZ removal was observed. A 35% reduction in CBZ occurred in the presence of surface water compared to complete suppression of the photocatalytic process in wastewater effluent

  5. Effect of dehydration rate on non-hydrolytic TiO2 thin film processing: Structure, optical and photocatalytic performance studies

    International Nuclear Information System (INIS)

    Highlights: ? Clear transparent TiO2 thin film prepared using non aqua sol-gel processing. ? The complexing agents plays significant role in the rate of dehydration due to hydrolysis. ? Faster dehydration significantly affects visible light transmittance and other properties. ? Diethanoalamine plays significant role in the crystallization and phase transformation. - Abstract: The influence of complexing agent diethanolamine (DEA) on the rate of dehydration due to hydrolysis in titania thin films prepared by non-aqua sol-gel process was investigated. The formation of complex with titanium precursor controls the rate of hydrolysis over wide range of temperature. The rate of hydrolysis with respect to complex formation and firing temperate was studied by using thermogravimetry and differential thermal analysis (TG-DTA). The role of complexing agent in the crystallization of anatase and phase transformation to rutile was studied by X-ray diffraction (XRD). Effect of complexing agent on the optical transmittance in the visible range was monitored by ultraviolet-visible absorption spectroscopy. Photocatalytic performance of the titania films was measured using methylene blue (MB) as the model contaminant. Mechanical characteristics such as hardness and adhesion of the film were rated by using scratch tests as per ASTM standards.

  6. Effect of Sn ratio on the photocatalytic degradation of methylene blue and soot of ink by TiO2-SnO2 nanostructured thin films

    International Nuclear Information System (INIS)

    The photocatalytic performance of rutile-, anatase- and mixed-phases of nanocomposite TiO2-SnO2 thin films, with different Sn ratios was tested. The absorption spectra of the prepared films show enhancement of high absorbance in the visible region for samples with Ti to Sn ratios of 3:1. Degradation of both methylene blue (MB) and soot of ink (SI) was examined by transmittance change under UV-vis irradiation. Sn doping improved the photocatalytic activity of the films. The results reveal that the smoother the sample surface and smaller the particle size; the highest the photocatalytic activity. Moreover, thin films doped with Ti to Sn ratios of 50:1 and 3:1 photocatalyst could more readily photodegrade MB and SI under visible-light irradiation. The high visible-light catalytic activity of the prepared photocatalyst resulted from the high absorbance in the visible-light range and also the reduced electron-hole recombination rate.

  7. Influence of TiO2 nanoparticles on the optical and structural properties of PPV thin films converted at low temperatures

    Directory of Open Access Journals (Sweden)

    B. Rostirolla

    2013-08-01

    Full Text Available In this work we studied the optical properties of poly(p-phenylene vinylene (PPV produced by the thermal conversion of a precursor polymer blended with a synthetic dye (Reactive Black 5. The production of PPV by this method decreases the overall time and cost of the process. We observed that the introduction of the dye resulted in an additional absorbance band near 550–700 nm, which can be beneficial to the photon harvesting capacity of the polymer if it is used as the donor material in a photovoltaic device. We studied how the optical and structures properties of this blend change when different quantities of TiO2 nanoparticles are introduced. For that, thin films were produced by the cast deposition of pre-PPV:dye:TiO2. The scanning electronic microscopic images showed that the inorganic semiconductor form large agglomerates of approximately 200 nm, indicating a very rough surface where the dye can be adsorbed. The analysis of photoluminescence and Raman peaks indicated a reduction of the mean conjugation length of the polymer chains in the presence of TiO2 nanoparticles.

  8. Photocatalytic degradation of methylene blue using undoped and Ag-doped TiO2 thin films deposited by a sol-gel process: Effect of the ageing time of the starting solution and the film thickness

    International Nuclear Information System (INIS)

    Undoped and Ag-doped TiO2 thin films were deposited on glass substrates by the sol-gel method. A novel propose to prepare the solution is the use of titanium monohydrate oxyacetyl acetonate as the starting reagent. The effect of the ageing time of the starting solution as well as the number of coatings on the photocatalytic degradation of methylene blue (MB) was studied. The variation of the absorption spectra shows the degradation of MB dissolved in water, as a result of the reaction produced on the surface of the films, and promoted by ultraviolet irradiation during 5 h. The results show an optimum photocatalytic activity, in the order of 35%, presented in the 5-immersion Ag-doped TiO2 thin films, deposited from 7- and 14-day aged solutions. On the other hand, the Ag-doped TiO2 films deposited at different coatings show small changes in the photocatalytic activity. Morphological studies show the presence of silver particles on the film surface, due to the different number of coatings, affecting the photocatalytic performance.

  9. Magnetoelastic sensors in combination with nanometer-scale honeycombed thin film ceramic TiO2 for remote query measurement of humidity

    Science.gov (United States)

    Grimes, Craig A.; Kouzoudis, Dimitris; Dickey, Elizabeth C.; Qian, D.; Anderson, M. A.; Shahidain, Rony; Lindsey, Maisha; Green, Leonard

    2000-05-01

    Ribbonlike magnetoelastic sensors can be considered the magnetic analog of an acoustic bell; in response to an externally applied magnetic field impulse the sensors emit magnetic flux with a characteristic resonant frequency. The magnetic flux can be detected external to the test area using a pick-up coil, enabling query remote monitoring of the sensor. The characteristic resonant frequency of a magnetoelastic sensor changes in response to mass loads [L. D. Landau and E. M. Lifshitz, Theory of Elasticity, 3rd ed. (Pergamon, New York, 1986), p. 100]. Therefore, remote query chemical sensors can be fabricated by combining the magnetoelastic sensors with a mass changing, chemically responsive layer. In this work magnetoelastic sensors are coated with humidity-sensitive thin films of ceramic, nanodimensionally porous TiO2 to make remote query humidity sensors.

  10. Enhancement of NMP Degradation Under UV Light by Nitrogen-Doped TiO2 Thin Films Using a Design of Experiment

    Directory of Open Access Journals (Sweden)

    F. Arefi-Khonsari

    2011-01-01

    Full Text Available Doping nitrogen within TiO2 is an effective way to enhance visible light photocatalysis due to a direct electron excitation from the N2p states within the band gap. However, nitrogen doping is not always efficient for UV photocatalytic activity. Here, different structures of N-doped TiO2 (TiOxNy have been prepared by reactive RF (13.56 MHz magnetron sputtering. The morphological, optical, structural, and photocatalytic properties of the films have been studied in order to investigate the competitive effect of the morphology and the chemical composition on the efficiency of the photocatalytic activity. The variation of surface wettability of the film over time in the dark and under visible and UV irradiation was also studied. The reduction in wettability by dark storage can be explained by the adsorption of hydrocarbon contamination on the thin film’s surface. Additionally, from water contact angle experiments, it was found that these films developed hydrophilic properties upon UV and visible illumination. The photoinduced change in the contact angle of water was due to the removal of hydrocarbon contamination on the surface and also the photo-oxidation of the water droplet. Samples prepared at high pressure gave the best photocatalytic activity, even though the deposition rate was lower at higher pressures (lower film thicknesses, due to the high specific surface area and the optimal presence of TiOxNy crystals in the lattice. However, at low pressure, the TiN crystals became more predominant, and acted as recombination centers for the photo-generated charge carriers. A design of experiments was used in order to optimize the deposition parameters to have the best photocatalytic activity. The high photocatalytic activity under UV light was found to be due to the introduction of discrete energy levels within the band gap, the increased sample wettability, and the higher specific surface area. However, the post annealing process did not effect the activity under UV irradiation. Using the response surface methodology, RSM, based on a design of experiment, DOE, we are able to achieve a good understanding of the complex processes involved in the deposition of the thin films and their effect on the photocatalytic activity.

  11. Formation of smooth and rough TiO2 thin films on fiberglass by sol-gel method

    Directory of Open Access Journals (Sweden)

    Claudio Frausto-Reyes

    2006-01-01

    Full Text Available Se ha usado la inmersión de substratos en un sol-gel hecho de un composito para preparar películas delgadas de TiO2 ya sean lisas o rugosas sobre fibra de vidrio. La deposición de películas se hizo desde una solución de isopropóxido de titanio (IV como precursor del sol-gel y bromuro de cetil-trimetil-amonio como surfactante. Las muestras fueron caracterizadas usando las técnicas de espectroscopia Raman y Uv-visible, así como la microscopia electrónica de barrido y de fuerza atómica. En casos especiales, la deposición de película consiste en un gel precursor de titanio que encapsula micelas de surfactante. La película de gel es convertida a la fase anatasa por calcinación a 500 °C, las películas lisas de TiO2 pueden tener propiedades ópticas y protectoras y la rugosidad de las películas de TiO2 puede aumentar su inherente actividad foto catalítica.

  12. Photocatalytic antimicrobial effect of TiO2 anatase thin-film-coated orthodontic arch wires on 3 oral pathogens

    OpenAIRE

    O?zyildiz, Figen; Uzel, Atac?; Hazar, Ays?e Serpil; Gu?den, Mustafa; O?lmez, Sultan; Aras, Is??l; Karaboz, I?smail

    2014-01-01

    The aim of this study was to introduce antimicrobial activity to stainless steel orthodontic arch wires by coating them with TiO2 in anatase form. Stainless steel (0.016 × 0.022 inch), D-rect (0.016 × 0.022 inch), and multistranded hammered retainer wires (0.014 × 0.018 inch) were coated with TiO2 anatase by the sol-gel dip coating method. The wires were assessed for their photocatalytic antimicrobial activity against Streptococcus mutans, Candida albicans, and Enterococcus faecalis. After...

  13. Methylene blue photoelectrodegradation under UV irradiation on Au/Pd-modified TiO2 films

    International Nuclear Information System (INIS)

    In this work TiO2 thin films were modified with gold/palladium (Au/Pd) bimetallic paticles by sputtering method. TiO2 films were deposited on ITO (SnO2:In) by Doctor Blade method and post-anneling. The properties of the films were studied through measurements of XRD (X-ray diffraction) and AFM (atomic force microscopy). The degradation of methylene blue was studied by UV-irradiated pure TiO2 and Au/Pd-modified TiO2 in aqueous solution. Langmuir-Hinshelwood model was used to obtain kinetic information. Photocatalytic study indicated that Au/Pd-modified TiO2 photocatalytic activity was better than TiO2 pure; the best half-life time for Au/Pd-modified TiO2 in photodegradation was 2.8 times smaller than TiO2 pure; finally the efficiency in methylene blue photodegradation was improved from 23% to 43% when Au/Pd-modified TiO2 films were used.

  14. Structural and electrochromic properties of TiO2 thin films prepared by metallorganic chemical vapor deposition

    International Nuclear Information System (INIS)

    Titanium dioxide thin films were deposited by Metallorganic Chemical Vapor Deposition at substrate temperatures ranging from 250 oC to 450 oC over soda lime glass and indium tin oxide coated glass substrates. X-ray diffraction studies show that films have a crystalline anatase structure at all the deposition temperatures. Particle size decreases and texture changes with the increase in substrate temperature. X-ray photoelectron spectroscopy confirms the appearance of a new well resolved state in the core level of Ti 2p spectrum shifted by 1.16 eV to lower binding energy due to the reduction of Ti+4 to Ti+3 upon litheation. Chronoamperometery, cyclic voltammetery and in situ UV-Vis spectrophotometeric studies were carried out on the prepared samples. Particle size and crystallinity control the electrochromic performance. The 350 oC film shows the highest ion storage capacity and the highest optical modulation along with an appreciable band gap broadening.

  15. TiO2 and WO3 thin films: Characterization, adsorption and photocatalytic degradation of oxalic acid and methylene blue.

    Czech Academy of Sciences Publication Activity Database

    Brüger, A.; Hrazdira, D.; Waldner, G.; Krýsa, J.; Jirkovský, Jaromír; Vinek, H.; Schlögl, R.; Rupprechter, G.

    Praha : VŠCHT Praha, 2006 - (Krýsa, J.; Kluso?, P.), s. 27-28 ISBN 978-80-7080-022-5. [New trends in application of photo and electro catalysis. Hnanice (CZ), 20.11.2006-22.11.2006] Institutional research plan: CEZ:AV0Z40400503 Keywords : photocatalysis * TiO2 Subject RIV: CG - Electrochemistry

  16. Investigation of the antibacterial effects of silver-modified TiO2 and ZnO plasmonic photocatalysts embedded in polymer thin films.

    Science.gov (United States)

    Tallósy, Szabolcs Péter; Janovák, László; Ménesi, Judit; Nagy, Elisabeth; Juhász, Ádám; Balázs, László; Deme, István; Buzás, Norbert; Dékány, Imre

    2014-10-01

    Nanosilver-modified TiO2 and ZnO photocatalysts were studied against methicillin-resistant Staphylococcus aureus on the surface and against naturally occurring airborne microorganisms. The photocatalysts/polymer nanohybrid films were prepared by spray coating technique on the surface of glass plates and on the inner surface of the reactive light source. The photoreactive surfaces were activated with visible light emitting LED light at ? = 405 nm. The optical properties of the prepared photocatalyst/polymer nanohybrid films were characterized by diffuse reflectance measurements. The photocatalytic properties were verified with the degradation of ethanol by gas chromatography measurements. The destruction of the bacterial cell wall component was examined with transmission electron microscope. The antibacterial effect of the photocatalyst/polymer nanohybrid films was tested with different methods and with the associated standard ISO 27447:2009. With the photoreactive coatings, an extensive disinfectant film was developed and successfully prepared. The cell wall component of S. aureus was degraded after 1 h of illumination. The antibacterial effect of the nanohybrid films has been proven by measuring the decrease of the number of methicillin-resistant S. aureus on the surface and in the air as the function of illumination time. The photocatalyst/polymer nanohybrid films could inactivate 99.9 % of the investigated bacteria on different thin films after 2 h of illumination with visible light source. The reactive light source with the inner-coated photocatalyst could kill 96 % of naturally occurring airborne microorganisms after 48 h of visible light illumination in indoor air sample. The TEM results and the microbiological measurements were completed with toxicity tests carried out with Vibrio fischeri bioluminescence bacterium. PMID:24497305

  17. Ultrathin-layer chromatography on SiO(2), Al(2)O(3), TiO(2), and ZrO(2) nanostructured thin films.

    Science.gov (United States)

    Wannenmacher, Julia; Jim, Steven R; Taschuk, Michael T; Brett, Michael J; Morlock, Gertrud E

    2013-11-29

    We explored four different inorganic oxides and determined their merits in miniaturized planar chromatography. Despite progression of chromatographic techniques over several decades, such alternatives to traditional planar silica gel stationary phases have not been fully evaluated. Glancing angle deposition(GLAD) provided an excellent platform for engineering nanostructured thin films in these materials for ultrathin-layer chromatography (UTLC). Separations of carotenoids and synthetic food dyes were used to investigate the attributes of SiO(2), Al(2)O(3), TiO(2), and ZrO(2)GLAD UTLC media. These anisotropic high surface area thin films possessed similar channel-like features but different chromatographic properties.TiO(2)and ZrO(2)media were especially interesting since analyte retention could be modified through sim-ple oxidation heat treatments and UV irradiation. Generally, oxidation reduced analyte retention while UV exposure increased retention. Changes in retention factor as large as ?hRF? 40 (for Acid Red 14 on titanium oxide) were achieved. Food dye mixtures were applied using consumer inkjet printers as per the Office Chromatography concept and separation performance was quantified using advanced video instrumentation designed for miniaturized plates. Enhanced time-resolved UTLC methods were used to calculate figures of merit from recorded dye separation videos. Small theoretical plate heights (<4 ?m)and low limits of detection (<2 ng per zone for the food dye tartrazine) were measured. The combination of engineered GLAD UTLC plates, inkjet application of analyte spots, time-resolved UTLC, and custom analysis algorithms enabled some of the best performance achieved on GLAD UTLC layers. Separations on the inorganic oxide thin films were also successfully hyphenated with electrospray ionization mass spectrometry for the first time. This investigation demonstrates the utility of alternative inorganic oxide GLADUTLC media and probes avenues of expanding the capabilities of miniaturized planar chromatography. PMID:24354005

  18. Synthesis and Annealing of Nanostructured TiO2 Films by Radio-Frequency Magnetron Sputtering

    Directory of Open Access Journals (Sweden)

    M.M. Hasan

    2009-01-01

    Full Text Available In this investigation, anatase TiO2 thin films were deposited on glass substrates at room temperature by RF magnetron sputtering at an elevated sputtering pressure of 3 Pa. The TiO2 films deposited at room temperature were annealed at different temperatures up to 873°K for 1 h. The TiO2 films were characterized by X-Ray Diffraction (XRD, Field-Emission Scanning Electron Microscopy (FESEM, Atomic Force Microscopy (AFM and UV-visible-NIR spectrophotometry. The XRD results reveal that the as-deposited film possess the anatase structure. Annealed TiO2 films show an insignificant change in crystallinity except of the fact that there is a slight increase for the film annealed at 600°C. The crystallite size increases from 44.5 to 48 nm with the increase of the annealing temperature. As-grown TiO2 film exhibits high visible transmittance with enhanced refractive index of 2.31 at a wavelength of 550 nm. The indirect optical band gaps of the as-deposited and annealed films have been estimated to be in the range of 3.39-3.42 eV. AFM observations reveal the compact and dense morphology of the as-deposited and annealed TiO2 thin films.

  19. Poly(vinyl chloride)-g-poly(2-(dimethylamino)ethyl methacrylate) graft copolymers templated synthesis of mesoporous TiO2 thin films for dye-sensitized solar cells

    International Nuclear Information System (INIS)

    A poly(vinyl chloride) (PVC) main chain was grafted with poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) containing a quaternary amine group using atom transfer radical polymerization. The successful synthesis of a PVC-g-PDMAEMA graft copolymer was confirmed by Fourier transform infrared, nuclear magnetic resonance, thermogravimetric analysis, and transmission electron microscopy. The PVC-g-PDMAEMA graft copolymer was used as a structure-directing agent (SDA) for the fabrication of a mesoporous thin film containing a titanium dioxide (TiO2) layer. To control the porosity of the resultant inorganic layer, the ratio of SDA to TTIP as well as the concentration of the sol–gel was varied. The structure and porosity of the mesoporous film were characterized by XRD and SEM analysis. The mesoporous TiO2 film fabricated on the FTO surface was used as a photoanode for the dye-sensitized solar cell (DSSC). DSSC performance was the greatest when using TiO2 film with a higher porosity and lower interfacial resistance. The highest energy conversion efficiency reached 3.2 % at 100 mW/cm2, which was one of the highest reported values for a quasi-solid-state DSSC with 600-nm-thick TiO2 film.

  20. Structural, magnetic and optical properties of Ni-doped TiO2 thin films deposited on silicon(1 0 0) substrates by sol–gel process

    International Nuclear Information System (INIS)

    Highlights: •Ni doping decreases the activation energy for the anatase-to-rutile transformation. •With increasing Ni content, the reversible ferromagnetism is found. •Sharp decrease of the EOBG at low Ni content is mainly related to phase composition. -- Abstract: Ni-doped TiO2 films were deposited on Si(1 0 0) substrates by sol–gel technique. X-ray photoelectron spectroscopy analysis suggests that the valence of Ni ion is in +2 and oxygen vacancies increase with increasing Ni content. X-ray diffraction measurements indicate that Ni doping catalyzes the anatase-to-rutile transformation (ART) of TiO2 films, which is due to the decrease of the ART activation energy. The reversible ferromagnetism of the samples with Ni fraction is found, which is due to an anatase-to-rutile junction destroying an F-center bound magnetic polaron. Optical properties of Ni-doped TiO2 films were studied by the ellipsometric spectra. With increasing Ni content, the optical band gap of TiO2 films is decreased from 3.56 to 3.34 eV, which may be related to phase composition and impurity band

  1. Using the voids. Evidence for an antenna effect in dye-sensitized mesoporous TiO2 thin films.

    Science.gov (United States)

    Hoertz, Paul G; Goldstein, Anna; Donley, Carrie; Meyer, Thomas J

    2010-11-18

    Composite structures of Ru(bpy)(2)(4,4'-(PO(3)H(2))(2)bpy)(2+) surface bound to nanocrystalline TiO(2) with an overlayer of Ru(bpy)(3)(2+) ion exchanged into Nafion, FTO|nanoTiO(2)-[Ru(bpy)(2)(4,4'-(PO(3)H(2))(2)bpy)](2+)/Nafion,Ru(bpy)(3)(2+) (FTO = fluorine-doped tin oxide), have been prepared and characterized. Steady-state emission and time-resolved lifetime measurements demonstrate that energy transfer occurs from Nafion,Ru(bpy)(3)(2+*) to adsorbed Ru(bpy)(2)(4,4'-(PO(3)H(2))(2)bpy)(2+) with an efficiency of ?0.49. Energy transfer sensitizes photoinjection by the adsorbed metal-to-ligand charge transfer (MLCT) excited state by an "antenna effect." PMID:20712329

  2. Investigation of a broadband TiO2/SiO2 optical thin-film filter for hybrid solar power systems

    International Nuclear Information System (INIS)

    Highlights: ? We present a new optical filter to get optimal performance of PV power system. ? The experimental results of the filter fabrication match well with numerical design. ? The measured results of a typical Si cell show efficiency increase using the filter. ? A proposed model for hybrid PV–TEG system demonstrates the benefits of the filter. -- Abstract: Using the technology of spectral selectivity to integrate different solar power generators in a hybrid system is a feasible way to improve the optical-electric efficiency. This paper presents an 82-layer broadband optical interference thin-film filter matching with crystalline silicon photovoltaic cells, which using TiO2 and SiO2 as fabrication materials and can be used in hybrid solar power systems like photovoltaic–thermoelectric generator (PV–TEG) systems. The design, optimization and fabrication process of the filter is described, high reflectance from 400 nm to 1100 nm as well as high transmittance from 1100 nm to 2500 nm over the broadband of solar spectrum are obtained. The classical electron beam evaporation plant is used to fabricate the filter. Four different incidence angles’ optical performances of the sample filter are measured which agree well with the numerical simulation results. The electrical characteristics of a typical Silicon photovoltaic cell using the fabricated sample filter are measured. An average efficiency increase of 3.24% for the solar cell with respect to the solar energy it receives can be obtained due to the filter. A calculation model for a hybrid PV–TEG system using this thin-film filter is proposed and the benefits of the filter for hybrid solar power systems are demonstrated.

  3. Effect of surface plasmon resonance in TiO2/Au thin films on the fluorescence of self-assembled CdTe QDs structure

    Science.gov (United States)

    Moura, I.; Cerqueira, M. F.; Melnikau, D.; Savateeva, D.; Rakovich, Y.; Borges, J.; Vaz, F.; Vasilevskiy, M.

    2015-04-01

    The exceptional properties of localised surface plasmons (LSPs), such as local field enhancement and confinement effects, resonant behavior, make them ideal candidates to control the emission of luminescent nanoparticles. In the present work, we investigated the LSP effect on the steady-state and time-resolved emission properties of quantum dots (QDs) by organizing the dots into self-assembled dendrite structures deposited on plasmonic nanostructures. Self-assembled structures consisting of water-soluble CdTe mono-size QDs, were developed on the surface of co-sputtered TiO2 thin films doped with Au nanoparticles (NPs) annealed at different temperatures. Their steady-state fluorescence properties were probed by scanning the spatially resolved emission spectra and the energy transfer processes were investigated by the fluorescence lifetime imaging (FLIM) microscopy. Our results indicate that a resonant coupling between excitons confined in QDs and LSPs in Au NPs located beneath the self-assembled structure indeed takes place and results in (i) a shift of the ground state luminescence towards higher energies and onset of emission from excited states in QDs, and (ii) a decrease of the ground state exciton lifetime (fluorescence quenching).

  4. Effect of hot-filament annealing in a hydrogen atmosphere on the electrical and structural properties of Nb-doped TiO2 sputtered thin films

    International Nuclear Information System (INIS)

    In this work Nb-doped TiO2 thin films were deposited by d.c.-pulsed reactive magnetron sputtering at 500 °C from a composite target with weight fractions of 96% Ti and 4% Nb, using oxygen as reactive gas. In order to enhance the conductive properties, the as-deposited samples were treated in vacuum with atomic hydrogen at a substrate temperature of 500 °C. The atomic hydrogen flow was generated by a hot filament, inside a high-vacuum chemical vapour deposition reactor, at a temperature of 1750 °C. In order to optimise the hydrogen hot-wire treatments, the H2 pressure was varied between 1.3 and 67 Pa, the treatment time was monitored between 1 and 5 min and the hot-filament current was changed between 12 and 17 A. Dark conductivity was measured as a function of temperature and its value at room temperature was extrapolated and used to assess the effect of the hydrogen annealing on the charge transport properties. A two-order of magnitude increase in dark conductivity was typically observed for optimised hydrogen treatments (10 Pa), when varying the hydrogen pressure, resulting in a minimum resistivity of ? 3 × 10?3 ? cm at room temperature. The maximum amount of atomic H incorporation in oxygen vacancies was determined to be ? 5.7 at.%. Carrier mobility and resistivity were also investigated using Hall effect measurements. Correlations between structural and electrical properties and the hydrogen treatment conditions are discussed. The conditions are discussed. The purpose of these films is to provide a transparent and conductive front contact layer for a-Si based photovoltaics, with a refractive index that better matches that of single and tandem solar cell structures. This can be achieved by an appropriate incorporation of a very small amount of cationic doping (Nb5+) into the titanium dioxide lattice.

  5. Size dependent electron transfer from CdTe quantum dots linked to TiO2 thin films in quantum dot sensitized solar cells

    International Nuclear Information System (INIS)

    In this present study, we demonstrate the size dependent charge transfer from CdTe quantum dots (QDs) into TiO2 substrate and relate this charge transfer to the actual behavior of a CdTe sensitized solar cell. CdTe QDs was synthesized using mercaptopropionic acid as the capping agent. The conduction band offset for TiO2 and CdTe QDs indicates thermodynamically favorable band edge positions for smaller QDs for the electron-transfer at the QD–TiO2 interface. Time-resolved emission studies were carried out for CdTe QD on glass and CdTe QD on TiO2 substrates. Results on the quenching of QD luminescence, which relates to the transfer kinetics of electrons from the QD to the TiO2 film, showed that at the smaller QD sizes the transfer kinetics are much more rapid than at the larger sizes. I–V characteristics of quantum dot sensitized solar cells (QDSSC) with different sized QDs were also investigated indicating higher current densities at smaller QD sizes consistent with the charge transfer results. The maximum injection rate constant and photocurrent were obtained for 2.5 nm CdTe QDs. We have been able to construct a solar cell with reasonable characteristics (Voc = 0.8 V, Jsc = 1 mA cm?2, FF = 60%, ? = 0.5%). - Highlights: • Size dependant charge transfer from quantum dots to TiO2. • Smaller quantum dot sizes promote higher current densities in solar cell. • Smaller quantum dots have favorable band edge positions and transport kinetics

  6. A corrosion-resistance superhydrophobic TiO2 film

    International Nuclear Information System (INIS)

    A superhydrophobic TiO2 film with water contact angle greater than 170° on Hastelloy substrate was fabricated through simply dip-coating method from TiO2 precursor solution containing TiO2 nanoparticles with the average diameter 25 nm, followed by heat-treatment and modification with fluoroalkylsilane (FAS) molecules. The as-obtained sample was characterized by scanning electron microscopy (SEM), X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), and water contact angle measurement respectively. Moreover, the dynamic light scattering (DLS) size distribution of TiO2 aggregated particles in the TiO2 precursor solution containing P25 particles was evaluated by Laser Particle Sizer. It is found that the TiO2 nanoparticles in TiO2 precursor solution play a crucial role to form high superhydrophobicity. Simultaneously, the superhydrophobic TiO2 film still showed great superhydrophobicity after corroded with strong acid or alkali solutions and protected the substrate from corrosion which should be critical to the potential application in industry.

  7. TiO2 and Fe-Doped TiO2 Thin Layers.

    Czech Academy of Sciences Publication Activity Database

    Dragounová, Pavlína; Morozová, Magdalena; Šolcová, Olga

    Bratislava : AXIMA Graphics Design & Printing Services, 2014, s. 26 ISBN 978-80-89475-13-1. [International Conference of Slovak Society of Chemical Engineering /41./. Tatranské Matliare (SK), 26.05.2014-30.05.2014] R&D Projects: GA TA ?R TA01020804 Grant ostatní: NATO(US) SPS984398 Institutional support: RVO:67985858 Keywords : sol-gel * TiO2 * Fe-TiO2 thin layers Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  8. Preparation of high quality nitrogen doped TiO2 thin film as a photocatalyst using a pulsed laser deposition method

    International Nuclear Information System (INIS)

    Nitrogen doped titanium oxide (TiO2-xNx) photocatalysts, which were reported to be activated by visible light irradiation as well as ultraviolet irradiation, have been prepared by pulsed laser deposition (PLD) method using TiN target in nitrogen/oxygen gas mixture. Crystalline structure, nitrogen states in the lattice, composition and surface morphology were analyzed by using X-ray diffraction, X-ray photoelectron spectroscopy and atomic force microscopy. As the results, it is found that film structure and properties strongly depend on target material and nitrogen concentration ratio in the gas mixture. The materials show anatase structure with nitrogen doped into TiO2 oxygen sites, which leads to band gap narrowing

  9. Photocatalysis and characterization of the gel-derived TiO2 and P-TiO2 transparent thin films

    International Nuclear Information System (INIS)

    The gel-derived TiO2 and P-TiO2 transparent films coated on fused-SiO2 substrates were prepared using a spin-coating technique. Effects of phosphorus dopants and calcination temperature on crystal structure, crystallite size, microstructure, light transmittance and photocatalytic activity of the films were investigated. By introducing P atoms to Ti-O framework, the growth of anatase crystallites was hindered and the crystal structure of anatase-TiO2 could withstand temperature up to 900 deg. C. The photocatalytic activities of the prepared films were characterized using the characteristic time constant (?) for the photocatalytic reaction. The titania film with a smaller ? value possesses a higher photocatalytic ability. After exposing to 365-nm UV light for 12 h, the P-TiO2 films calcined between 600 deg. C and 900 deg. C can photocatalytically decomposed ? 84 mol% of the methylene blue in water with corresponding ? ? 7.1 h, which were better than the pure TiO2 films prepared at the same calcination temperature.

  10. Sol-gel deposited TiO2 film on NiTi surgical alloy for biocompatibility improvement

    International Nuclear Information System (INIS)

    TiO2 thin films were prepared on NiTi surgical alloy by sol-gel method. The forming process, surface morphology and structure of the films were studied by X-ray diffraction and atomic force microscopy. The results showed that nm-scale TiO2 particles were embedded in the film of 205 nm thickness. The film existed mainly in the form of anatase, and the film was compact and smooth. The electrochemical corrosion measurement indicated that TiO2 thin film, as a protective layer, was effective for improving corrosion resistance of NiTi alloy. Additionally, in vitro blood compatibility of the film and NiTi alloy was evaluated by dynamic clotting time and blood platelets adhesion tests. The results showed that NiTi alloy coated with TiO2 film had improved blood compatibility

  11. Nanoindentation investigation of mechanical properties of ZrO2, ZrO2–Y2O3, Al2O3 and TiO2 thin films deposited on stainless steel OC 404 substrate by spray pyrolysis

    International Nuclear Information System (INIS)

    Highlights: • ZrO2, ZrO2–Y2O3, Al2O3 and TiO2 films were deposited by spray pyrolysis. • Surface morphology and structure of the films were characterized via SEM and X-ray. • Mechanical properties of films were investigated by nanoindentation and was established that their values exceed these for pure metals. - Abstract: Thin ZrO2, ZrO2–Y2O3, Al2O3 and TiO2 films were deposited by spray pyrolysis method on stainless steel OC 404 substrate with thickness 50 ?m. The thicknesses of obtained films varied from 0.50 to 0.64 ?m. The surface morphology and structure of the films were characterized by scanning electron microscopy in secondary electron imaging mode. The X-ray diffraction measurements for determination of the lattice parameters, the average crystallite size and the sample strain were performed. Mechanical properties of investigated films and substrate were investigated by nanoindentation experiments, using Nano Indenter G200 (Agilent Technologies). As a result of nanoindentation experiments, load–displacement curves were obtained and two mechanical characteristics of the substrate and investigated films – indentation hardness (HIT) and indentation modulus (EIT) – were calculated using Oliver and Pharr approximation method. Dependence of indentation modulus and indentation hardness on depth of indentation was investigated as well

  12. Pt Catalyst Supported within TiO2 Mesoporous Films for Oxygen Reduction Reaction

    International Nuclear Information System (INIS)

    In this study, dispersed Pt nanoparticles into mesoporous TiO2 thin films are fabricated by a facile electrochemical deposition method as electro-catalysts for oxygen reduction reaction. The mesoporous TiO2 thin films coated on the fluorine-doped tin oxide glass by screen printing allow a facile transport of reactants and products. The structural properties of the resulted Pt/TiO2 electrode are evaluated by field emission scanning electron microscopy, energy dispersive X-ray spectrometry, X-ray diffraction, and X-ray photoelectron spectroscopy. Cyclic voltammetry measurements are performed to study the electrochemical properties of the Pt/TiO2 electrode. Further study demonstrates the stability of the Pt catalyst supported within TiO2 mesoporous films for the oxygen reduction reaction

  13. Effect of SnO2 on the photocatalytical properties of TiO2 films

    International Nuclear Information System (INIS)

    TiO2/SnO2 thin films with different tin atomic percentages were successfully prepared on glass substrates by the spray pyrolysis method from an alcoholic solution of TiO[C5H7O2]2 with different concentrations of SnCl4. The TiO2/SnO2 thin films prepared at 450 deg. C presented the anatase phase in polycrystalline configuration from %Sn = 0 in the starting solution up to %Sn = 20, at higher tin content the films present an amorphous configuration. The resulting thin films have a homogeneous surface structure with some porosity. The photocatalytical properties of the films were evaluated with the degradation of methylene blue. The products of the degradation reaction were identified by 1H nuclear magnetic resonance and the film properties were studied by atomic force microscopy, scanning electron microscopy, UV-Vis spectroscopy, and X-ray diffraction

  14. Solar photocatalytic degradation of phenol using pyrolitic TiO2 films deposited inside a tubing

    International Nuclear Information System (INIS)

    Solar photocatalytic degradation of phenol was obtained using TiO2 films deposited inside glass tubing. TiO2 thin films inside tubing were obtained by spray-gel technique using a titanium isopropoxide solution conveniently diluted in ethanol. The gas carrier flux, air pressure and temperature were kept during deposition at 5 L/min, 200 kPa, and 200 oC, respectively. Experiments were performed using either the solar radiation or a 300 W lamp simulating the UVA solar radiation component. In order to concentrate the radiation a reflective surface was placed in the back part of the tube. The initial concentration of phenol solution was 20 ppm, and the phenol concentration during the experiment was followed using a standard colorimetric method when aminoantipirine reacts in the sample giving a colored complex. The volume of the phenol solution was limited with a solid aluminum rod placed axially to the glass tube. The obtained TiO2 films were amorphous, but after an annealing at 450oC for 1 h the films crystallize to anatase structure and present photocatalytic activity. The films morphology observed by scanning electron microscopy presented a uniform film and agglomerates of TiO2, the size of the agglomerates increases as Ti isopropoxide/ethanol molar ratio of the starting solution decreases. The precursor concentration solution and film thickness of TiO2 for phenol degradation was optimized. (au for phenol degradation was optimized. (author)

  15. Flexible InGaZnO thin film transistors using stacked Y2O3/TiO2/Y2O3 gate dielectrics grown at room temperature

    International Nuclear Information System (INIS)

    In this Letter, we report a low operation voltage and high mobility flexible InGaZnO thin-film transistor (TFT) using room-temperature processed Y2O3/TiO2/Y2O3 gate dielectric. The flexible IGZO TFT showed a low threshold voltage of 0.75 V, a small sub-threshold swing of 137 mV/decade, a good field effect mobility of 32.7 cm2/V s, and a large Ion/Ioff ratio of 1.7 x 106. The low operation voltage, small sub-threshold swing and high mobility could be ascribed to the combination of high-? TiO2 and large band gap Y2O3, which provide the potential to meet the requirements of low-temperature and low-power portable electronics. (copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  16. Propriedades estruturais e eletrônicas de nanofilmes de TiO2 anatase: cálculos B3LYP-D* em sistemas periódicos bidimensionais / Stuctural and electronic properties of anatase TiO2 thin films: periodic B3LYP-D* calculations in 2D systems

    Scientific Electronic Library Online (English)

    Anderson R., Albuquerque; Iêda M. G., Santos; Júlio R., Sambrano.

    1318-13-01

    Full Text Available [...] Abstract in english Structural and electronic properties of titanium dioxide (TiO2) thin films, in anatase phase, were investigated using periodic 2D calculations at density functional theory (DFT) level with B3LYP hybrid functional. The Grimme dispersion correction (DFT/B3LYP-D*) was included to better reproduce struc [...] tural features. The electronic properties were discussed based on the band gap energy, and proved dependent on surface termination. Surface energies ranged from 0.80 to 2.07 J/m², with the stability orders: (101) > (100) > (112) > (110) ~ (103) > (001) >> (111), and crystal shape by Wulff construction in accordance with experimental data.

  17. The fabrication of nanocomposite thin films with TiO2 nanoparticles by the layer-by-layer deposition method for multifunctional cotton fabrics

    International Nuclear Information System (INIS)

    A multilayer nanocomposite film composed of anatase TiO2 nanoparticles was fabricated on cationically modified woven cotton fabrics by the layer-by-layer molecular self-assembly technique. For cationic surface charge, cotton fabrics were pre-treated with 2,3-epoxypropyltrimethylammonium chloride (EP3MAC) by a pad-batch method. Attenuated total reflectance Fourier transform infrared spectroscopy (FTIR), x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were used to verify the presence of deposited nanolayers. Photocatalytic activities of the nanocomposite films were evaluated through the degradation of red wine pollutant. Nano-TiO2 deposition enhanced the protection of cotton fabrics against UV radiation in comparison with the untreated cotton fabrics. Air permeability and whiteness value analysis was performed on the fabrics before and after the treatment with TiO2 nanoparticles by the layer-by-layer deposition method. Tensile strength tests of the warp and weft yarns were performed to evaluate the effect of solution pH value changes during the alternate dipping procedures. For the first time the durability of the effect of the self-assembled multilayer films on the cotton fabric functional properties was analyzed after 10 and 20 washing cycles at 40 deg. C for 30 min.

  18. Photoelectrochemical characterization and photocatalytic properties of mesoporous TiO 2 / ZrO 2 films

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available Optically transparent, crack-free mesoporous titania and zirconia-doped titania thin film photocatalysts were fabricated by sol-gel technique, using nonionic amphiphilic block copolymer Pluronic P123 as template. The structural and optical properties of these films were characterized using SEM, low-angle XRD, and UV/Vis spectroscopy, hexane adsorption investigation. Band gap energy and the position of flatband potentials were estimated by photoelectrochemical measurements. Enhancing of photocatalytic activity of zirconia-doped films relative to pure TiO 2 originates from an anodic shift of the valence band edge potential. Catalytic activity of mesoporous TiO 2 and TiO 2 / ZrO 2 ( 5 –50% of ZrO 2 films in the processes of Cr VI to Cr III photoreduction and 2,4-dinitroaniline photooxidation correlates with crystalline size and growth with increasing of specific surface area of the samples.

  19. Photoactivity passivation of TiO2 nanoparticles using molecular layer deposited (MLD) polymer films

    International Nuclear Information System (INIS)

    Pigment-grade anatase TiO2 particles (160 nm) were passivated using ultra-thin insulating films deposited by molecular layer deposition (MLD). Trimethylaluminum (TMA) and ethylene glycol (E.G) were used as aluminum alkoxide (alucone) precursors in the temperature range of 100-160 oC. The growth rate varied from 0.5 nm/cycle at 100 oC to 0.35 nm/cycle at 160 oC. Methylene blue oxidation tests indicated that the photoactivity of pigment-grade TiO2 particles was quenched after 20 cycles of alucone MLD film, which was comparable to 70 cycles of Al2O3 film deposited by atomic layer deposition (ALD). Alucone films would decompose in the presence of water at room temperature and would form a more stable composite containing aluminum, which decreased the passivation effect on the photoactivity of TiO2 particles.

  20. Photoelectrochemical characterization and photocatalytic properties of mesoporous TiO2/ZrO2 films

    Directory of Open Access Journals (Sweden)

    Olga Linyucheva

    2006-02-01

    Full Text Available Optically transparent, crack-free mesoporous titania and zirconia-doped titania thin film photocatalysts were fabricated by sol-gel technique, using nonionic amphiphilic block copolymer Pluronic P123 as template. The structural and optical properties of these films were characterized using SEM, low-angle XRD, and UV/Vis spectroscopy, hexane adsorption investigation. Band gap energy and the position of flatband potentials were estimated by photoelectrochemical measurements. Enhancing of photocatalytic activity of zirconia-doped films relative to pure TiO2 originates from an anodic shift of the valence band edge potential. Catalytic activity of mesoporous TiO2 and TiO2/ZrO2 (5–50% of ZrO2 films in the processes of CrVI to CrIII photoreduction and 2,4-dinitroaniline photooxidation correlates with crystalline size and growth with increasing of specific surface area of the samples.

  1. Time-dependent absorption of TiO2 optical thin films under pulsed and continuous wave 790??nm laser irradiation.

    Science.gov (United States)

    Zhang, Xuerong; Emmert, Luke A; Rudolph, Wolfgang

    2013-12-01

    The time-dependent absorption at 790 nm of TiO2 films prepared by ion-beam sputtering (IBS) and electron-beam evaporation (EBE) was measured. The pump source was a Ti:sapphire oscillator that was operated in CW and pulsed (50 fs) modes. The absorption coefficient of the IBS film under CW illumination was 8??cm-1, independent of time and power. Under pulsed illumination, there was evidence of three-photon absorption, and the total absorption increased 10-fold over time at the highest measured irradiance. The absorption of the EBE film had higher initial absorption (?24??cm-1) and increased under both CW and pulsed illumination with time. An electron state model based on band-to-band excitation and electron trapping is presented that explains the observed results. The implications for laser-induced damage of oxide coatings are discussed. PMID:24513825

  2. Electrochemical Doping of Compact TiO2 Thin Layers.

    Czech Academy of Sciences Publication Activity Database

    Zukalová, Markéta; Bouša, Milan; Bastl, Zden?k; Jirka, Ivan; Kavan, Ladislav

    2014-01-01

    Ro?. 118, ?. 45 (2014), s. 25970-25977. ISSN 1932-7447 R&D Projects: GA ?R(CZ) GAP108/12/0814 Institutional support: RVO:61388955 Keywords : electrochemistry * TiO2 * thin layers Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.835, year: 2013

  3. Fabrication of TiO2 Thick Film for Photocatalyst from Commercial TiO2 Powder

    International Nuclear Information System (INIS)

    Photocatalytic activity of TiO2 thick film ceramics made of commercial TiO2 powder has been studied. The TiO2 powder was nano sized one that was derived from dried TiO2 suspension. The TiO2 suspension was made by pouring some blended commercial TiO2 powder into some amount of water. The paste of TiO2 was made by mixing the nano sized TiO2 powder with organic vehicle and glass frit. The paste was spread on a glass substrate. The paste was dried at 100 deg. C and heated at different temperatures (400 deg. C and 500 deg. C) for 60 minutes to produce thick film ceramics. The photocatalytic activity of these films was evaluated by measuring the concentration of a solution of methylene blue where the thick films were inside after being illuminated by UV light at various periods of times. The initial concentration of the methylene blue solution was 5 ppm. Structural analyses were carried out by X-ray diffraction (XRD). The XRD analyses showed that the produced thick film ceramic had mainly crystal structure of anatase. According to the photocatalytical data, it was known that the produced thick film ceramics were photocatalyst which were capable of decomposing an organic compound such as the methylene blue

  4. TiO2 films photocatalytic activity improvements by swift heavy ions irradiation

    International Nuclear Information System (INIS)

    TiO2 thin films synthesized by sol–gel on glass substrates are irradiated by 90 MeV Xe ions at various fluences and room temperature under normal incidence. The structural, electrical, optical and surface topography properties before and after Xe ions irradiation are investigated. X-ray diffraction (XRD) reveals that the crystallinity is gradually destroyed, and the films become amorphous above 5×1012 ions/cm2. The band gap is not affected by Xe ions irradiation as evidenced from the optical measurements. By contrast, the conductivity increases with raising Xe fluence. The energy band diagram established from the electrochemical characterization shows the feasibility of TiO2 films for the photo-electrochemical chromate reduction. Xe ion irradiation results in enhanced photocatalytic activity in aquatic medium, evaluated by the reduction of Cr(VI) into trivalent state. TiO2 films irradiated at 1013 Xe/cm2 exhibit the highest photoactivity; 69% of chromate (10 ppm) is reduced at pH ?3 after 4 h of exposure to sunlight (1120 mW cm?2) with a quantum yield of 0.06%. - Highlights: • Swift heavy ions irradiation induces TiO2 amorphization and conductivity increase. • Xenon ions irradiation generates oxygen vacancies and hillocks on the surface film. • The photoactivity of TiO2 is improved by xenon ions irradiation

  5. Two-component transparent TiO2/SiO2 and TiO2/PDMS films as efficient photocatalysts for environmental cleaning.

    Czech Academy of Sciences Publication Activity Database

    Novotná, P.; Zita, J.; Krýsa, J.; Kalousek, Vít; Rathouský, Ji?í

    2007-01-01

    Ro?. 79, ?. 2 (2007), s. 179-185. ISSN 0926-3373 R&D Projects: GA MŠk 1M0577 Institutional research plan: CEZ:AV0Z40400503 Keywords : TiO2 * SiO2 * PDMS * thin film Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.651, year: 2007

  6. Characterisation of samarium and nitrogen co-doped TiO2 films prepared by chemical spray pyrolysis

    International Nuclear Information System (INIS)

    Highlights: ? The TiO2:N:Sm thin films deposited by chemical spray pyrolysis have anatase structure. ? According to XPS, N is incorporated into the TiO2 matrix. ? N-doping increases and Sm-doping reduces the crystallite size of the TiO2:N:Sm films. ? Incorporation of N strongly suppresses the Sm3+ PL emission. - Abstract: The sol–gel chemical spray pyrolysis method was used to deposit samarium and nitrogen co-doped TiO2 films onto a quartz substrate at a growth temperature of 450 °C using pulsed spray solution feed, followed by annealing at 500 °C for 2 h in air. The obtained films exhibited anatase structure independent of the doping level. According to XRD analysis, the mean crystallite size of the undoped TiO2, TiO2:N(25) and TiO2:N(5):Sm(5) films was 32, 38 and 20 nm, respectively. According to AFM, the undoped TiO2 film consisted of agglomerates with a size of 30–200 nm. N-doping (25 at%) transformed the agglomerates into individually distinctive grains with a size of ca. 30 nm, while Sm doping (5 at%) caused a significant decrease in the average diameter of the agglomerates to ca. 100 nm. The RMS roughness of the undoped TiO2 film was 1.7 nm; doping resulted in the formation of smoother films with RMS roughness of 0.9–1.4 nm. XPS data indicated that the Sm and N dopants were incorporated into the TiO2 crystal lattice and/or adscrystal lattice and/or adsorbed on the surface of the film. An increasing nitrogen concentration in the spray solution correlates to a systematic suppressing of the photoluminescence intensity of Sm3+.

  7. Synthesis of amorphous TiO2 modified ZnO nanorod film with enhanced photocatalytic properties

    International Nuclear Information System (INIS)

    Highlights: • Synthesis of amorphous TiO2 modified ZnO nanorod films. • A thin layer of amorphous TiO2 was dispersed over the surface of nanorod. • Disordered TiO2 phase improved the optical absorption. • The samples showed enhanced photocatalytic activity. - Abstract: Amorphous TiO2 modified ZnO nanorod films were synthesized via multi-step processes: ZnO nanorod films were prepared by a wet chemical method. Amorphous TiO2 was then anchored on the tops and sides of the nanorods through immersion in tetrabutyltitanate solution for hydrolysis. The as-prepared samples were characterized for the phase structure, chemical state and surface morphology as well as optical absorption using X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and ultraviolet–visible (UV–vis) spectrophotometer. The results showed that the nanorod films were covered by amorphous TiO2 layers, and their visible light absorption ability was strengthened. The photocatalytic studies revealed that TiO2 modified films exhibited enhanced photocatalytic efficiency for decomposition of methyl orange under ultraviolet–visible excitation, which might be attributed to the increased UV–vis light absorption and the separation of the charge carrier and prolonged electron lifetime due to the interface between TiO2 and ZnO

  8. Resistive Switching in ALD ZnO and TiO2 Films

    Science.gov (United States)

    Waggoner, Todd; Co, John

    2010-03-01

    Resistive switching in metal oxide thin films has recently become a major scientific interest due to the possibility of producing low power, non-volatile resistive random access memory (ReRAM). Theories proposed for the switching mechanism typically involve the migration of oxygen vacancies under an applied electric field. Resulting from local increases in vacancy concentration, conducting filaments can form between device electrodes. The process is reversible by either applying a stronger voltage bias across the device to burn out the filaments or by reversing the applied field. This allows for the design of devices with unipolar or bipolar operation. A material comparison of ZnO and TiO2 thin films grown by atomic layer deposition (ALD) demonstrate different switching behavior in our devices. ALD TiO2 films have been prepared in the past but results typically show a wide variance. Here ZnO and TiO2 are directly compared utilizing Al electrodes. So far most work has been done using Pt electrodes on TiO2 thin films. Investigations show that device yield, performance, cycle endurance, and stability appear to differ significantly as a result of the chosen dielectric.

  9. Enhance of electrical properties of resistive switches based on Sr0.1Ba0.9TiO3 and TiO2 thin films by employing a Ni-Cr alloy as contact

    International Nuclear Information System (INIS)

    We have investigated the electric-field-induced resistance-switching phenomena of ReRAM cells based on Sr0.1Ba0.9TiO3 and TiO2 thin films fabricated by rf-sputtering technique. Thin films were sandwiched between Pt, Ti and nichrome bottom electrode and Cu top electrode. The I-V measurements at room temperature are non-linear and hysteretic. Cells based on Sr0.1Ba0.9TiO3 present a unipolar resistance-switching phenomenon and it is symmetric with respect to the voltage polarity, while cells based on TiO2 have a bipolar resistance-switching with asymmetric behavior. From the I-V measurements we demonstrated that the nichrome enhances the resistance-switching characteristics of the cells. A reduction of the voltage needed to achieve the HRS-LRS and LRS-HRS transitions are found and a very clear transition between these states is accomplished, in comparison with ReRAM cells fabricated with Pt and Ti electrodes, whose voltage values are large and no clear transitions are presented. This improvement in resistance-switching behavior can be explained due to O2 vacancies formed in the interface because higher affinity for oxygen of nickel and chromium.

  10. Photoactive TiO2 films on cellulose fibres: synthesis and characterization

    OpenAIRE

    ZECCHINA, Adriano; UDDIN, mohammed jasim; BONINO, Francesca Carla; Bordiga, Silvia; SCARANO, Domenica; Spoto, Giuseppe; CESANO, Federico

    2007-01-01

    The preparation of photoactive fibres has been successfully developed by depositing and grafting TiO2 nanoparticles on cellulose fibres by using a sol-gel method at low temperature (similar to 100 degrees C)-designed for practical applications. The original and treated fibres have been characterized by several techniques (SEM, HRTEM, FTIR, Raman, UV-vis spectroscopy, XRD, and TGA). The TiO2 nanoparticles, 3-5 run in size, have been found to form a homogeneous thin film on the fibre surface, w...

  11. Wet Etching of TiO2-Based Precursor Amorphous Films for Transparent Electrodes

    Science.gov (United States)

    Ohkubo, Junpei; Hirose, Yasushi; Sakai, Enju; Nakao, Shoichiro; Hitosugi, Taro; Hasegawa, Tetsuya

    2011-01-01

    We investigated wet etching of Nb-doped anatase TiO2 (TNO) transparent conducting thin films and their precursors in an amorphous phase deposited by rf sputtering on glass substrates. The polycrystalline TNO films showed a very low etching rate of less than 0.06 nm/min in concentrated sulfuric acid (H2SO4) even at elevated temperatures up to 95 °C. In contrast, H2SO4 etched the precursor films at a rate of 1.4 nm/min at 95 °C. The etching rate of the amorphous films followed the Arrhenius equation, leading us to conjecture that a much higher etching rate of ˜230 nm/min can be achieved at 170 °C. These results indicate that wet-etching of precursor amorphous films prior to crystallization represents a practical and low-cost lithographic technique for patterning TiO2-based transparent electrodes.

  12. Improvement of (004) texturing by slow growth of Nd doped TiO2 films

    International Nuclear Information System (INIS)

    In this work, we present preferred (004) texturing of sputter deposited titanium dioxide (TiO2) films on glass substrates as a consequence of Nd doping at very slow growth rate. Nd concentration was varied from 0.0 to 2.0 atomic percent (at. %) in TiO2 thin films deposited under identical growth conditions, i.e., the growth rate of 0.6 Å/s and at 500 °C. At 2 at. % Nd, complete texturing along (004) plane was observed, as indicated by the X-ray diffraction analyses. Morphology of the deposited TiO2 films from pure to 2 at. % Nd doped TiO2 films showed faceted to planar growth. Visualization of electrical and structural analysis (VESTA) software revealed that the change in the morphology was due to preferential growth in (004) orientation. Raman spectroscopy highlighted the phonon confinement in the Eg mode, and a red shift was observed due to an increase in the anti-symmetry in bonding with increased Nd concentration. XPS results confirmed the variation in oxygen vacancy concentration along with the reduction of Ti and Nd valance states with the change in the dopant concentration. Our experiments confirmed that the substitution of Nd at Ti sites was responsible for texturing in (004) orientation and this was possible by growing films at a very slow rate.

  13. Enhancement of ferromagnetism upon thermal annealing in plasma assisted MBE grown mixed-phase Mn-doped insulating TiO2 thin films

    Science.gov (United States)

    Xu, L. M.; Yu, Y. P.; Xing, X. J.; Wu, X. Y.; Li, S. W.

    2008-08-01

    We have investigated the properties of Mn-doped thin films grown on SrTiO3 (100) substrate by plasma assisted molecular beam epitaxy (PAMBE). The microstructural, electrical, optical, and magnetic properties of these thin films have been characterized systematically, with a primary focus on establishing a correlation between magnetic and electrical properties. We have shown that these thin films exhibit room temperature ferromagnetism, and appear to enhance ferromagnetism upon thermal annealing, though the films show high resistance. The possible mechanism for the phenomena is also discussed. It is suggested that the growth condition, oxygen vacancies and structural and interfacial defects, and the bound magnetic polaron (BMP) model account for the magnetism enhancement.

  14. Effect of pyrolytic temperature on the properties of TiO2/ITO films for hydrogen sensing

    Science.gov (United States)

    Vijayalakshmi, K.; David Jereil, S.; Karthick, K.

    2015-03-01

    Titanium dioxide (TiO2) thin films were prepared on ITO (2 2 2) coated glass substrates by spray pyrolysis technique. The influence of substrate temperature on the orientation, phase, vibrational bands and band gap energy of TiO2 films were discussed. The X-ray diffraction patterns of the films revealed preferentially oriented (1 0 1) TiO2 anatase phase at the substrate temperature of 300 °C and 350 °C. Fourier transform infrared spectra of the films showed the significant sharpening of absorption band at ?645 cm-1 with increase in substrate temperature, which clearly indicates the formation of anatase phase dependent on substrate temperature. Fourier Raman Spectra of the films showed the significant presence of long range order anatase TiO2 phase. The optical measurements of the film prepared at different substrate temperatures revealed the direct band gap of 3.15-3.63 eV and indirect band gap of 3.48-3.73 eV, characteristic of TiO2 anatase phase. To understand the enhancement of sensing performances of TiO2 films with substrate temperature, the gas sensing mechanism of the films towards 400 sccm of hydrogen at room temperature was studied and discussed.

  15. Effect of pyrolytic temperature on the properties of TiO2/ITO films for hydrogen sensing.

    Science.gov (United States)

    Vijayalakshmi, K; Jereil, S David; Karthick, K

    2015-03-01

    Titanium dioxide (TiO2) thin films were prepared on ITO (222) coated glass substrates by spray pyrolysis technique. The influence of substrate temperature on the orientation, phase, vibrational bands and band gap energy of TiO2 films were discussed. The X-ray diffraction patterns of the films revealed preferentially oriented (101) TiO2 anatase phase at the substrate temperature of 300°C and 350°C. Fourier transform infrared spectra of the films showed the significant sharpening of absorption band at ?645cm(-1) with increase in substrate temperature, which clearly indicates the formation of anatase phase dependent on substrate temperature. Fourier Raman Spectra of the films showed the significant presence of long range order anatase TiO2 phase. The optical measurements of the film prepared at different substrate temperatures revealed the direct band gap of 3.15-3.63eV and indirect band gap of 3.48-3.73eV, characteristic of TiO2 anatase phase. To understand the enhancement of sensing performances of TiO2 films with substrate temperature, the gas sensing mechanism of the films towards 400sccm of hydrogen at room temperature was studied and discussed. PMID:25498820

  16. Photovoltaic performance improvement of dye-sensitized solar cells through introducing In-doped TiO2 film at conducting glass and mesoporous TiO2 interface as an efficient compact layer

    International Nuclear Information System (INIS)

    In-doped TiO2 thin film was introduced at the interface of fluorine-doped tin oxide (FTO) substrate and mesoporous TiO2 film by spin-coating method, and its application as a new compact layer material for dye-sensitized solar cells (DSSCs) was investigated. The scanning electron microscopy (SEM), UV-visible spectroscopy, current-voltage characteristics, Mott-Schottky analysis, electrochemical impedance spectroscopy (EIS) analysis and open-circuit voltage decay (OCVD) technique are used to characterize the morphology, optical transmittance and flat-band potentials (Vfb) of In-doped titania compact film and its effect to the photoelectron conversion process. It was found that In-doping increased the transmittance of TiO2 compact layer, the interfacial resistance between FTO substrate and porous TiO2 film and the flat-band potential of TiO2 film. The In-doped TiO2 compact layer effectively suppressed the charge recombination from FTO to the electrolyte, increased the optical absorption of dye and then increased the short-circuit photocurrent density (Jsc). Furthermore, In-doped TiO2 compact layer acted as a weak energy barrier, which increased the electron density in the mesoporous TiO2 film, thus improved open-circuit photovoltage (Voc). As a result, the overall energy conversion efficiency of the DSSC with In-doped TiO2 compact layer was enhanced by 11.9% and 6.9% compared to the DSSC without compact layer and with pure TiO2 compact layer, respectively. It indicated that In-doped TiO2 is a promising compact layer material for dye-sensitized solar cells

  17. Effect of Ta2O5/TiO2 thin film on mechanical properties, corrosion and cell behavior of the NiTi alloy implanted with tantalum

    International Nuclear Information System (INIS)

    The NiTi shape memory alloy has been modified by plasma immersion ion implantation (PIII) with Ta at different incident currents to improve the corrosion resistance and other surface and biological properties. The surface topography, chemical components, mechanical properties, corrosion resistance and cytocompatibility are investigated. Atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) revealed that Ta implantation led to the formation of compact Ta2O5/TiO2 nano-film on the surface of the NiTi alloy. The results of Auger electron spectroscopy (AES) showed that Ni was suppressed in the superficial surface layer of the modified NiTi alloy samples. The results of nano-indentation illustrated a lower level of nano-hardness and Young's modulus after Ta implantation. Potentiodynamic anodic polarization curves showed that the corrosion resistance of NiTi alloys was enhanced by Ta implantation. Cells reached confluency and a double-layered structure had developed after cultured for three days. The NiTi alloy modified by a moderate incident current possesses a uniform and slippery surface morphology and the largest surface roughness, leading to the best corrosion resistance and the highest cell proliferation rate, respectively.

  18. Optical properties of SiO 2-TiO 2 thin film waveguides obtained by the sol-gel method and their applications for sensing purposes

    Science.gov (United States)

    ?ukowiak, Anna; Dylewicz, Rafal; Patela, Sergiusz; Str?k, Wieslaw; Maruszewski, Krzysztof

    2005-07-01

    Optical properties of silica-titania thin films prepared by the sol-gel technique are presented. The layers were deposited on glass slides or silica wafers by a dip coating process. Samples were prepared from different mixtures of silica and titania alkoxides. The stable, crack-free and transparent coatings were obtained after heating in the air at 60 °C and 500 °C. The layers coated on oxidized silica plates (on SiO 2 optical substrate layers) can be used as planar waveguides. Coupling light into silica-titania thin films was possible by applying grating couplers. This functional device, fabricated by the holographic method, allows to couple laser light in and out of the planar waveguides by exciting various waveguide modes. The possibility of using silica-titania thin films with entrapped sensing molecules as an optical waveguide sensor is also discussed.

  19. Effect of a TiO2 Buffer Layer on the Properties of ITO Films Prepared by RF Magnetron Sputtering

    Directory of Open Access Journals (Sweden)

    Daeil Kim

    2013-10-01

    Full Text Available Sn-doped In2O3 (ITO thin films were prepared by radio frequency magnetron sputtering without intentionalsubstrate heating on bare glass and TiO2-deposited glass substrates to investigate the effect of a TiO2 buffer layer onthe electrical and optical properties of ITO films. The thicknesses of TiO2 and ITO films were kept constant at 5 and100 nm, respectively. As-deposited ITO single layer films show an optical transmittance of 75.9%, while ITO/TiO2 bilayeredfilms show a lower transmittance of 76.1%. However, as-deposited ITO/TiO2 films show a lower resistivity(9.87×10-4 ?cm than that of ITO single layer films. In addition, the work function of the ITO film is affected by the TiO2buffer layer, with the ITO/TiO2 films having a higher work-function (5.0 eV than that of the ITO single layer films. Theexperimental results indicate that a 5-nm-thick TiO2 buffer layer on the ITO/TiO2 films results in better performancethan conventional ITO single layer films.

  20. Caracterización de películas serigráficas de TiO2/alginato / Characterization of TiO2/alginate screenprinting films

    Scientific Electronic Library Online (English)

    M.A., Soto-Borbón; V.M., Sánchez-Corrales; M.E., Trujillo-Camacho.

    Full Text Available En este trabajo se presentan los resultados de la caracterización de películas serigráficas formadas por TiO2 y alginato soportadas sobre sustratos de vidrio, aprovechando las propiedades adherentes/adsorbentes del biopolímero, con la finalidad de aplicarlas en la degradación fotocatalítica de conta [...] minantes. El análisis de este material se realizó mediante la caracterización estructural, química y óptica de películas de compositos de TiO2/alginato elaboradas en una proporción 90/10 en peso, mediante el empleo de las técnicas de perfilometría, DRX, SEM, EDS, FT-IR y UV-Vis. Se lograron películas homogéneas con un espesor controlado por el grosor de la malla serigráfica, con excelente adherencia a sustratos de vidrio y una mejor dispersión de las partículas de TiO2. Al aplicarse en la remoción de los tintes Methyl violeta 2B y Safranina O el desempeño de la película de TiO2/alginato puede ser similar al del TiO2 solo. Abstract in english In this paper we report the characterization of screen printing films formed by TiO2 and a natural polymer (alginate) supported on glass substrates; in order to take advantage of the adhesive/adsorbents biopolymer properties, achieve a better semiconductor dispersion and a better adhesion to the sub [...] strate. The analysis of this material was accomplished by structural characterization of chemical and optical films of TiO2/alginato composites prepared in a ratio 90/10 by weight, by employing techniques such as profilometry, XRD, SEM, EDS, FT-IR and UV-Vis. When applied to the removal of Methyl Violet 2B (MV-2B) and Safranin O dyes, these films exhibited the same performance as TiO2 alone.

  1. TiO2 films prepared by micro-plasma oxidation method for dye-sensitized solar cell

    International Nuclear Information System (INIS)

    Nanocrystalline TiO2 films are widely investigated as the electrodes of dye-sensitized solar cell(s) with different preparation methods. In this paper, thin titanium dioxide films have been prepared on titanium plates by the micro-plasma oxidation method in the sulfuric acid solution. The thin TiO2 films were sensitized with a cis-RuL2(SCN)2.2H2O (L = cis-2,2'-bipyridine-4,4'-dicarboxylic acid) ruthenium complex and implemented into a dye-sensitized solar cell configuration. The influence of reaction current density (10, 15, 20, 25 and 30 A dm-2) on the structural and the surface morphology of the films was investigated by X-ray diffraction, scanning electron microscopy, atom force microscopy and X-ray photoelectricity spectroscopy. Impedance analysis for dye-sensitized solar cells was carried out by electrochemical impedance spectroscopy. The results show that the rise of current density leads to the increase in the amount of rutile and the thickness of the TiO2 film, which makes the TiO2 films have different photovoltages and photocurrents. The relatively higher photoelectricity properties were obtained in the TiO2 films prepared at a current density of 20 A dm-2. The open-circuit voltage and the short-circuit current are 605 mV and 165 ?A cm-2, respectively

  2. Investigation into the photo-induced change in wettability of hydrophobized TiO2 films

    International Nuclear Information System (INIS)

    The photo-induced change in wettability of hydrophobized TiO2 films has been investigated for steel coated with acidic TiO2 nanosols containing varying concentrations of dispersed nanocrystalline titania, such as Degussa P25. The photo-induced change in wettability was evaluated by measuring the time-dependent drop of water contact angle (WCA) after samples had been soaked in either n-octyltriethoxysilane (OTS) or decanoic acid (DA). TiO2 films treated in this way exhibit superhydrophobic behaviour, with WCA greater than 160 deg. After radiation with UV (black light), the superhydrophobic properties are transformed into superhydrophilic properties, with WCA of almost 0 deg. As P25 content and layer thickness increase, high rates of photo-induced change are found, but a moderate calcination regime is required. On the other hand, hardness and E modulus pass through a maximum at 25 wt% P25, so that a P25 content between 25 and 50 wt% is the optimum for practical uses. With such stable coatings, wettability can be controlled over a wide range, and the switch between hydrophobic and hydrophilic states can be carried out repeatedly when DA is used as the hydrophobizing agent. Use of a low calcination temperature (450 deg. C) for the intermediate annealing of the single layers in multilayer coatings and a short final sintering step at a relatively high temperature (e.g. 630 deg. C for 10 min) allow the preparation of relatively thin TiO2e preparation of relatively thin TiO2 films on steel with a high photoactivity

  3. Characterization of TiO2 films prepared by pulsed laser deposition

    International Nuclear Information System (INIS)

    Epitaxial titanium dioxide thin films with anatase and rutile structure have been deposited by pulsed laser deposition (ArF excimer laser and Nd:YAG laser) under the controlled O2 atmosphere. Epitaxial anatase films have been prepared on several kinds of oxide substrates with different lattice parameters. The anatase TiO2 (001) films have been prepared on LaAlO3 (001), LSAT (001), SrTiO3 (001) and YSZ (001) substrates. Also the high quality epitaxial rutile TiO2 (100) films were grown on ?-Al2O3 (0001) substrate. In addition, Cr, Nb, Ta and W doped rutirle TiO2 (100) films were successfully prepared. The quality of films and crystallographic relationships were assessed by x-ray diffraction, x-ray pole figures and Rutherford backscattering spectroscopy (RBS)/channeling. The photocatalytic activity was evaluated by Photo-Induced Charge Separation measurement (PITCS) and measuring decomposition rates of methylene blue. (author)

  4. Quantitative Measurements of Photocatalytic CO-Oxidation as a Function of Light Intensity and Wavelength over TiO2 Nanotube Thin Films in mu-Reactors

    DEFF Research Database (Denmark)

    Vesborg, Peter Christian Kjærgaard; In, Su-il

    2010-01-01

    Gas-phase photooxidation of CO over TiO2 catalysts (P25 and TiO2 nanotubes) in mu-reactors with quantitative product detection was used to study turnover as a function of illumination intensity over 4 orders of magnitude. Turnover was found to be of order 0.84 in illumination intensity. A CO photooxidation action spectrum was also recorded for TiO2 nanotubes. The action spectrum was used to calculate both the incident photon to product efficiency (IPPE) and the absorbed photon to product efficiency (APPE). The wavelength dependence of the IPPE was found to follow the absorption spectrum while the APPE was found to have a peak around 345 nm with a value of about 0.8%.

  5. Effects of SrTiO3/TiO2 buffer layer on structural and electrical properties of BiFeO3 thin films grown on GaN (0002)

    Science.gov (United States)

    Luo, W. B.; Zhu, J.; Zeng, H. Z.; Liao, X. W.; Chen, H.; Zhang, W. L.; Li, Y. R.

    2011-05-01

    BiFeO3(BFO) films were deposited by pulsed laser deposition on GaN(0002)/c-sapphire. X-ray diffraction data show that BFO(111) epitaxial films was deposited on SrTiO3/TiO2 double-layer buffered GaN, compared to the polycrystalline film grown directly on GaN. The epitaxial relationships of BFO film with SrTiO3/TiO2 buffer layers were BFO [11-2](111)//GaN [1-100](0002) as revealed by XRD phi scans. Furthermore, BFO films on SrTiO3/TiO2 buffer exhibited enhanced electric properties compared to these deposited directly on GaN. The remnant polarization was improved about 30% while the leakage current was reduced by nearly three orders of magnitude. The epitaxial growth promoted by the SrTiO3/TiO2 buffer layer is a pivotal parameter in the improved electric properties of BFO films on GaN (0002).

  6. Influence of process parameters on the growth of pure-phase anatase and rutile TiO2 thin films deposited by low temperature reactive magnetron sputtering

    Scientific Electronic Library Online (English)

    H., Toku; R.S., Pessoa; H.S., Maciel; M., Massi; U.A., Mengui.

    2010-09-01

    Full Text Available In this work is investigated the optimal conditions for deposition of pure- phase anatase and rutile thin films prepared at low temperatures (less than 150ºC) by reactive dc magnetron sputtering onto well- cleaned p- type Si substrates. For this, the variation of deposition plasma parameters as subs [...] trate- to- target distance, total gas pressure, oxygen concentration, and substrate bias were studied and correlated with the characteristics of the deposited films. The XRD analysis indicates the formation of pure rutile phase when the substrate is biased at voltages between - 200 and - 300 V. Pure anatase phase is only attained when the total pressure is higher than 0.7 Pa. Moreover, it's noticeable a strong dependence of surface roughness with parameters studied.

  7. Influence of operating parameters on surface properties of RF glow discharge oxygen plasma treated TiO2/PET film for biomedical application

    International Nuclear Information System (INIS)

    In this paper, a thin transparent titania (TiO2) film was coated on the surface of flexible poly(ethylene terephthalate) (PET) film using the sol–gel method. The surface properties of the obtained TiO2/PET film were further improved by RF glow discharge oxygen plasma as a function of exposure time and discharge power. The changes in hydrophilicity of TiO2/PET films were analyzed by contact angle measurements and surface energy. The influence of plasma on the surface of the TiO2/PET films was analyzed by atomic force microscopy (AFM) as well as the change in chemical state and composition that were investigated by X-ray photo electron spectroscopy (XPS). The cytotoxicity of the TiO2/PET films was analyzed using human osteoblast cells and the bacterial eradication behaviors of TiO2/PET films were also evaluated against Staphylococcus bacteria. It was found that the surface roughness and incorporation of oxygen containing polar functional groups of the plasma treated TiO2/PET films increased substantially as compared to the untreated one. Moreover the increased concentration of Ti3+ on the surface of plasma treated TiO2/PET films was due to the transformation of chemical states (Ti4+ ? Ti3+). These morphological and chemical changes are responsible for enhanced hydrophilicity of the TiO2/PET films. Furthermore, the plasma treate/sub>/PET film exhibited no citotoxicity against osteoblast cells and antibacterial activity against Staphylococcus bacteria which can find application in manufacturing of biomedical devices. - Graphical abstract: Mechanism of plasma treatment on the surface of TiO2/PET films. - Highlights: • Investigated the surface properties of TiO2/PET films modified by O2 plasma • Studied the effect of operating parameters on surface properties of TiO2/PET films • Mechanism of the plasma treatment on TiO2/PET was clearly investigated. • Utilized various characterization techniques for analyzing the O2 plasma treated films • Examined antibacterial activity and cytotoxicity of the TiO2/PET films

  8. Photocatalytic activity of Cr-doped TiO2 nanoparticles deposited on porous multicrystalline silicon films.

    Science.gov (United States)

    Hajjaji, Anouar; Trabelsi, Khaled; Atyaoui, Atef; Gaidi, Mounir; Bousselmi, Latifa; Bessais, Brahim; El Khakani, My Ali

    2014-01-01

    This work deals with the deposition of Cr-doped TiO2 thin films on porous silicon (PS) prepared from electrochemical anodization of multicrystalline (mc-Si) Si wafers. The effect of Cr doping on the properties of the TiO2-Cr/PS/Si samples has been investigated by means of X-ray diffraction (XRD), atomic force microcopy (AFM), photoluminescence, lifetime, and laser beam-induced current (LBIC) measurements. The photocatalytic activity is carried out on TiO2-Cr/PS/Si samples. It was found that the TiO2-Cr/PS/mc-Si type structure degrades an organic pollutant (amido black) under ultraviolet (UV) light. A noticeable degradation of the pollutant is obtained for a Cr doping of 2 at. %. This result is discussed in light of LBIC and photoluminescence measurements. PMID:25313302

  9. Enhanced performance of dye-sensitized solar cell via surface modification of mesoporous TiO2 photoanode with electrodeposited thin TiO2 layer

    International Nuclear Information System (INIS)

    Highlights: ? TiO2-modified photoanode composed of compact underlayer and efficient electron transport network was fabricated directly by anodic electrodeposition in an aqueous TiCl3 electrolyte. ? The electrodeposited thin TiO2 layer could bridge gaps between TiO2 nanoparticles and improve the electrical contact at the FTO/TiO2 interface, leading to an efficient electron transport. ? The electrodeposited compact TiO2 layer could cover the exposed surface area of FTO to the electrolyte, which contributes to the suppression of the charge recombination. ? We demonstrated that the TiO2-modified photoanode significantly enhances the photovoltaic properties of the DSSC compared to the bare photoanode. - Abstract: Surface modification of porous TiO2 photoanode with a thin compact TiO2 layer was carried out by means of anodic electrodeposition in an aqueous TiCl3 electrolyte. Results indicated that the electrodeposited thin TiO2 layer could bridge gaps between TiO2 nanoparticles and improve the electrical contact at the FTO (fluoride-doped tin oxide)/TiO2 interface, leading to an efficient electron transport. In addition, the thin compact TiO2 layer could cover the exposed surface area of FTO to the electrolyte, which contributes to the suppression of the charge recombination. The surface treatment of mesoporous TiOurface treatment of mesoporous TiO2 photoanode via aqueous electrochemical route is an effective way to improve the performance of DSSC (dye-sensitized solar cell), which could increase the short-circuit current density, and reduce the dark current density compared to DSSCs with bare and TiCl4-treated TiO2 photoanodes. The photoelectron conversion efficiency of DSSC was increased from 7.3 to 8.2% after employing the TiO2-modified photoanode.

  10. Optical Properties of Sputter Deposited Transparent and Conducting TiO2:Nb Films

    OpenAIRE

    Maghanga, Christopher M.; Niklasson, Gunnar; Granqvist, Claes-go?ran

    2009-01-01

    Transparent and conducting thin films of TiO2:Nb were prepared on glass by reactive dc magnetron sputtering in Ar + O-2. Post-deposition annealing in vacuum at 450 degrees C led to good electrical conductivity and optical transparency. The optical properties in the sub-bandgap region were in good agreement with Drude free electron theory, which accounts for intraband absorption. The band gap of the films was found to be in the range of 3.3 to 3.5 eV and signifies the onset of interband absorp...

  11. Shifting to the red the absorption edge in TiO2 films: a photoacoustic study

    Scientific Electronic Library Online (English)

    F., Gordillo-Delgado; K., Villa-Gómez; E, Marín.

    2011-03-01

    Full Text Available When Titanium dioxide in contact with a polluted water sample is irradiated with ultraviolet light, electron-hole pairs can be generated, which can react with oxygen and water producing free radicals that can degrade the pollutants, changing them into harmless compounds for the environment. The ultr [...] aviolet component of the solar radiation is around 7%. Therefore, it is convenient to modify the TiO2 films crystalline structure for obtaining photocatalytical processes with visible light. In this work we report on the growth of TiO2 thin films by the Sol-gel technique considering the incorporation of AgNO3 in the initial solution containing the precursor. The concentration of the AgNO3 saline solution was changed between 5 and 30% to control the grain size of the grown TiO2 nanocrystals, impregnating 6 layers over glass slide substrates and using a sintering temperature of 600 °C. The obtained films were characterized structurally by means of X-ray diffraction. The shift in the forbidden energy bandwidth value to the red part of the optical absorption spectrum was evidenced by Photoacoustic Spectroscopy. The photocatalytic activity was tested on a solution of methylene blue using also the Photoacoustic technique.

  12. Mechanism of photocatalytic bacterial inactivation on TiO2 films involving cell-wall damage and lysis

    OpenAIRE

    Pulgarin, C.; Kiwi, J.; Nadtochenko, V.

    2012-01-01

    This article addresses the cell wall damage of Escherichia coil (from now on E. coil) by TiO2 suspensions. The dynamics of TiO2 photocatalysis by thin films layers is described. The films were characterized by FTIR spectroscopy and atomic force microscopy (AFM). The E coil complete inactivation is shown to be due to the partial damage of the cell-wall components (peroxidation). A small increase in the cell wall disorder concomitant with a decrease of the cell wall functional groups leads to h...

  13. Micro and macro scratch and microhardness study of biocompatible DLC and TiO2 films prepared by laser.

    Czech Academy of Sciences Publication Activity Database

    Mikšovský, Jan; Lukeš, J.; Tolde, Z.; Remsa, Jan; Kocourek, Tomáš; Jelínek, Miroslav

    2013-01-01

    Ro?. 647, JAN (2013), 25-29. ISSN 1022-6680 Institutional support: RVO:68378271 Keywords : thin films * adhesion * scratch test * microhardness * Young´s modulus * diamond-like-carbon (DLC) * titanium dioxide (TiO 2 ). Subject RIV: BM - Solid Matter Physics ; Magnetism

  14. Influence of porous morphology on optical dispersion properties of template free mesoporous titanium dioxide (TiO2) films

    International Nuclear Information System (INIS)

    This paper focuses the influence of porous morphology on the microstructure and optical properties of TiO2 films prepared by different sol concentration and calcination temperatures. Mesoporous TiO2 thin films were prepared on the glass substrates by sol-gel dip coating technique using titanium (IV) isopropoxide. Porous morphology of the films can be regulated by chemical kinetics and is studied by scanning electron microscopy. The optical dispersion parameters such as refractive index (n), oscillator energy (Ed), and particle co-ordination number (Nc) of the mesoporous TiO2 films were studied using Swanepoel and Wemple-DiDomenico single oscillator models. The higher precursor concentration (0.06 M), films exhibit high porosity and refractive index, which are modified under calcination treatment. Calcinated films of low metal precursor concentration (0.03 M) possess higher particle co-ordination number (Nc = 5.05) than that of 0.06 M films (Nc = 4.90) due to calcination at 400 deg. C. The lattice dielectric constant (E?) of mesoporous TiO2 films was determined by using Spintzer model. Urbach energy of the mesoporous films has been estimated for both concentration and the analysis revealed the strong dependence of Urbach energy on porous morphology. The influence of porous morphology on the optical dispersion properties also has been explained briefly in this papereen explained briefly in this paper

  15. Structural and magnetic properties of Mn-doped anatase TiO2 films synthesized by atomic layer deposition

    Science.gov (United States)

    Sellers, Meredith C. K.; Seebauer, Edmund G.

    2011-08-01

    Mn-doped anatase TiO2 (Mn: 1.2, 2.4 at%) thin films were grown on Si(100) via atomic layer deposition (ALD). The synthesis utilized Ti(OCH(CH3)2)4 and H2O as ALD precursors and Mn(DPM)3 as a dopant source. X-ray photoelectron spectroscopy measurements indicate that Mn is successfully doped in the TiO2 matrix and reveal information about film composition and elemental chemical states. Microstructure, crystallinity, and density were investigated with scanning electron microscopy, X-ray diffraction, and X-ray reflectivity. All ALD-synthesized films exhibited room-temperature ferromagnetism; the microstructure, density, and magnetic field-dependent magnetization of the TiO2 varied with the concentration of Mn. ALD permits precise composition and thickness control, and much higher process throughput compared to alternative techniques.

  16. Microporous TiO2-WO3/TiO2 films with visible-light photocatalytic activity synthesized by micro arc oxidation and DC magnetron sputtering

    Science.gov (United States)

    Wu, Kee-Rong; Hung, Chung-Hsuang; Yeh, Chung-Wei; Wu, Jiing-Kae

    2012-12-01

    This study reports the preparation of microporous TiO2-WO3/TiO2 films with a high surface area using a two-step approach. A porous WO3/TiO2 template was synthesized by oxidizing a titanium sheet using a micro arc oxidation (MAO) process. This sheet was subsequently overlaid with a visible light (Vis)-enabled TiO2 (N,C-TiO2) film, which was deposited by codoping nitrogen (N) and carbon (C) ions into a TiO2 lattice using direct current magnetron sputtering. The resulting microporous TiO2-WO3/TiO2 film with a 0.38-?m-thick N,C-TiO2 top-layer exhibited high photocatalytic activity in methylene blue (MB) degradation among samples under ultraviolet (UV) and Vis irradiation. This is attributable to the synergetic effect of two-step preparation method, which provides a highly porous microstructure and the well-crystallized N,C-TiO2 top-layer. This is because a higher surface area with high crystallinity favors the adsorption of more MB molecules and more photocatalytic active areas. Thus, the microporous TiO2-WO3/TiO2 film has promising applications in the photocatalytic degradation of dye solution under UV and Vis irradiation. These results imply that the microporous WO3/TiO2 can be used as a template of hybrid electrode because it enables rapid fabrication.

  17. Preparation and Characterization of Pure Rutile TiO2 Nanoparticles for Photo catalytic Study and Thin Films for Dye-Sensitized Solar Cells

    International Nuclear Information System (INIS)

    Pure rutile-phase TiO2 (r-TiO2) was synthesized by a simple one pot experiment under hydrothermal condition using titanium (IV) n-butoxide as a Ti-precursor and HCl as a peptizer. The TiO2 products were characterized by XRD, TEM, ESCA, and BET surface area measurement. The r-TiO2 were rodlike in shape with average size of ? 61 x 32 nm at hydrothermal temperature of 220 degree C for 10 h. Hydrothermal treatment at longer reaction time increased the tendency of crystal growth and also decreased the BET surface area. The degradation of methylene blue was selected as a test reaction to confer the photocatalytic activity of as-obtained r-TiO2. The results showed a strong correlation between the structure evolution, particle size, and photocatalytic performance of r-TiO2. Furthermore, the r-TiO2-based solar cell was prepared for the photovoltaic characteristics study, and the best efficiency of ? 3.16% was obtained.

  18. Natural and persistent superhydrophilicity of SiO2/TiO2 and TiO2/SiO2 bi-layer films

    International Nuclear Information System (INIS)

    Sol-gel SiO2/TiO2 and TiO2/SiO2 bi-layer films have been deposited from a polymeric SiO2 solution and either a polymeric TiO2 mother solution (MS) or a derived TiO2 crystalline suspension (CS). The chemical and structural properties of MS and CS bi-layer films heat-treated at 500 deg. C have been investigated by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscospy. Water contact angle measurements show that MS SiO2/TiO2 and CS TiO2/SiO2 bi-layer films exhibit a natural superhydrophilicity, but cannot maintain a zero contact angle for a long time over film aging. In contrast, CS SiO2/TiO2 bi-layer films exhibit a natural, persistent, and regenerable superhydrophilicity without the need of UV light. Superhydrophilic properties of bi-layer films are discussed with respect to the nature of the TiO2 single-layer component and arrangement of the bi-layer structure, i.e. TiO2 underlayer or overlayer

  19. Sunlight photocatalysis in coral-like TiO2 film

    International Nuclear Information System (INIS)

    To improve the quantum efficiency of TiO2 film irradiated by sunlight, coral-like TiO2 film composed by nanorods and a nanonet structure was prepared by anodizing Ti in HF-Na2SiF6-FeCl3 solution. The coral-like TiO2 film revealed an improvement over the TiO2 nanotube under sunlight in both optical absorption and photocatalytic activity such as photodegradation of reactive brilliant red. Under sunlight irradiation, the photoelectrocatalytic degradation rate of a coral-like TiO2/Ti electrode (45.2%) was about four times higher than that of a nanotube TiO2/Ti electrode (11.9%) at 1.5 V potential application.

  20. The Effect of Dye Density on the Efficiency of Photosensitization of TiO2 Films: Light-Harvesting by Phenothiazine-Labelled Dendritic Ruthenium Complexes

    OpenAIRE

    Lin-Yong Zhu; Douglas Magde; Whitesell, James K.; Marye Anne Fox

    2009-01-01

    A family of dendritic tris-bipyridyl ruthenium coordination complexes incorporating two or four carboxylate groups for binding to a TiO2 surface site and another dendritic linker between the metal complex and highly absorptive dyes were formulated as thin films on TiO2 coated glass. The family included phenothiazine-substituted dendrons of increasing structural complexity and higher optical density. The dye-loaded films were characterized by steady-state emission and absorption measurements a...

  1. Silver Doped TiO2 Nanostructure Composite Photocatalyst Film Synthesized by Sol-Gel Spin and Dip Coating Technique on Glass

    Directory of Open Access Journals (Sweden)

    Mohammad Hossein Habibi

    2008-04-01

    Full Text Available New composite films (P25SGF-MC-Ag, MPC500SGF-MC-Ag, and ANPSGF-MC-Ag have been synthesized by a modified sol-gel method using different particle sizes of TiO2 powder and silver addition. Nanostructure TiO2/Ag composite thin films were prepared by a sol-gel spin and dip coating technique. while, by introducing methyl cellulose (MC porous, TiO2/Ag films were obtained after calcining at a temperature of 500Co. The as-prepared TiO2 and TiO2/Ag films were characterized by X-ray diffractometry, and scanning electron microscopy to reveal the structural and morphological differences. In addition, the photocatalytic properties of these films were investigated by degrading methyl orange (MO under UV irradiation. After 500Co calcination, the microstructure of MC-TiO2 film without Ag addition exhibited a microstructure, while significant sintering effect was noticed with Ag additions and the films exhibited a porous microstructure. Nanostructure anatase-phase TiO2 can be observed with respect to the sharpening of XRD diffraction peaks. The photodegradation of porous TiO2 deposited with 5×10−4 mol Ag exhibited the best photocatalytic efficiency, where 69% methyl orange can be decomposed after UV exposure for 1 hour.

  2. Surface properties and biocompatibility of nanostructured TiO2 film deposited by RF magnetron sputtering

    Science.gov (United States)

    Majeed, Asif; He, Jie; Jiao, Lingrui; Zhong, Xiaoxia; Sheng, Zhengming

    2015-02-01

    Nanostructured TiO2 films are deposited on a silicon substrate using 150-W power from the RF magnetron sputtering at working pressures of 3 to 5 Pa, with no substrate bias, and at 3 Pa with a substrate bias of -50 V. X-ray diffraction (XRD) analysis reveals that TiO2 films deposited on unbiased as well as biased substrates are all amorphous. Surface properties such as surface roughness and wettability of TiO2 films, grown in a plasma environment, under biased and unbiased substrate conditions are reported according to the said parameters of RF power and the working pressures. Primary rat osteoblasts (MC3T3-E1) cells have been cultured on nanostructured TiO2 films fabricated at different conditions of substrate bias and working pressures. The effects of roughness and hydrophilicity of nanostructured TiO2 films on cell density and cell spreading have been discussed.

  3. Enhanced adsorption of atrazine from aqueous solution by molecularly imprinted TiO2 film

    Science.gov (United States)

    Zhang, Chunjing; Yan, Jinlong; Zhang, Chunxiao; Yang, Zhengpeng

    2012-07-01

    TiO2 film imprinted by atrazine molecule at the surface of quartz crystal was prepared using molecular imprinting and surface sol-gel process. The molecularly imprinted TiO2 film was characterized by scanning electron microscopy and cyclic voltammetry, and the atrazine adsorption was investigated by quartz crystal microbalance (QCM) technique. In comparison with non-imprinted TiO2 film, the molecularly imprinted TiO2 film exhibits high selectivity for atrazine, better reversibility and a much higher adsorption capacity for the target molecule, the adsorption equilibrium constant estimated from the in situ frequency measurement is about 6.7 × 104 M-1, which is thirteen times higher than that obtained on non-imprinted TiO2 film.

  4. Elliptical concave microlens arrays built in the photosensitive TiO2/ormosils hybrid films

    Science.gov (United States)

    Zhang, Xuehua; Que, Wenxiu; Javed, Hafiz M. Asif; Wei, Wei

    2014-11-01

    Photosensitive TiO2/organically modified silane hybrid thin films were prepared by a low-temperature sol-gel spin-coating technique. Optical and structural properties of the hybrid films with different titanium contents were characterized by prism coupling technique, UV-visible spectroscopy, Fourier transform infrared spectroscopy, and thermal gravimetric analysis. Advantages for fabrication of elliptical concave micro-lens arrays (MLAs) based on the as-prepared hybrid films were demonstrated by combining polydimethylsiloxane soft mold with a UV-cured imprint technique. Results indicate that the as-prepared hybrid films have great applicability for the fabrication of photonic components, and the fabrication technique provides a simple and cost-effective way for the fabrication of the sol-gel elliptical concave MLAs.

  5. TiO2 film properties as a function of processing temperature, volume 3

    Science.gov (United States)

    Fitzgibbons, E. T.; Sladek, K. J.; Hartwig, W. H.

    1972-01-01

    Thin film TiO2 was produced at 150 C by chemical vapor deposition using hydrolysis of tetraisopropyl titanate. Films were amorphous as grown, but annealing in air caused crystallization, with anatase formed beginning at 350 C and rutile at 700 C. Density and index of refraction increased substantially with increasing anneal temperature, while etch susceptibility in HF and H2SO4 decreased. Comparison with literature data showed two groups of processes. One group yields films having properties that gradually approach those of rutile with increasing process temperature. The other group gives rutile directly at moderate temperatures. Deposition of amorphous film followed by etching and annealing is suggested as a means for pattern definition.

  6. Well-Organized Meso-Macroporous TiO2/SiO2 Film Derived from Amphiphilic Rubbery Comb Copolymer.

    Science.gov (United States)

    Jeon, Harim; Lee, Chang Soo; Patel, Rajkumar; Kim, Jong Hak

    2015-04-15

    We report the facile synthesis of a well-organized meso-macroporous TiO2/SiO2 thin film with high porosity and good interconnectivity from a binary mixture (i.e., titania precursor and polymer template). Our process is based on self-assembly of the amphiphilic rubbery comb copolymer, poly(dimethylsiloxane)-g-poly(oxyethylene methacrylate) (PDMS-g-POEM) with titanium tetraisopropoxide (TTIP). SiO2 is self-provided by thermal oxidation of PDMS chains during calcination under air. The selective, preferential interaction between TTIP and the hydrophilic POEM chains was responsible for the formation of well-organized TiO2/SiO2 films, as supported by transmission electron microscopy, scanning electron microscopy, X-ray photospectroscopy, and X-ray diffraction analyses. We investigated in detail the effect of precursor content, solvent type, and polymer concentration on thin film morphology. Photodegradation of methyl orange by the well-organized meso-macroporous TiO2/SiO2 film was greater than that of a dense TiO2 film prepared without PDMS-g-POEM as well as a SiO2-etched TiO2 film. These results indicate that the well-organized structure and SiO2 doping of the TiO2 film play a pivotal role in enhancing its photocatalytic properties. PMID:25805232

  7. Preparation of photo-catalysis TiO2 films by combined plasma surface treatment

    International Nuclear Information System (INIS)

    TiO2 films with excellent bonding strength were fabricated on stainless steel substrate by plasma surface alloying and thermal oxidation duplex processing. Controllable elemental distribution and structure of the films could be achieved at 400-600 degree C. The films were characterized by metallography, glow discharge spectrometer (GDOES) and X-ray diffraction. The results show that the TiO2 films are of dense and uniform anatase. The Ti and O contents of the films are in gradient distribution. Phenol-containing wastewater was used to test photo-catalytic performance of the films. The TiO2 films have a degradation rate of phenol of about 73.5% in 3 h, much higher than commercial products of TiO2 powders. (authors)

  8. Antimicrobial and Barrier Properties of Bovine Gelatin Films Reinforced by Nano TiO2

    Directory of Open Access Journals (Sweden)

    R. Nassiri

    2013-11-01

    Full Text Available The effects of nano titanium dioxide incorporation were investigated on the water vaporpermeability, oxygen permeability, and antimicrobial properties of bovine gelatin films. The nano TiO2 (TiO2-N was homogenized by sonication and incorporated into bovine gelatin solutions at different concentrations(e.g. 1, 2, 3, and 5% w/w of dried gelatin. The permeability of the films to water vapor and oxygen wassignificantly decreased by incorporating of low concentration TiO2-N to gelatin solutions. TiO2-N gelatin filmsshowed an excellent antimicrobial activity against Staphylococcus aureus and Escherichia coli. Theseproperties suggest that TiO2-N has the potential as filler in gelatin-based films for using as an active packagingmaterials in pharmaceutical and food packaging industries.

  9. GISAXS investigation of TiO2 nanoparticles in PS-b-PEO block-copolymer films

    International Nuclear Information System (INIS)

    Ordered 2D-arrays of TiO2 nanoparticles were synthesised by a poly(styrene)-block-poly(ethylene oxide) (PS-b-PEO) block-copolymer templated sol-gel process within a thin polymer film. The order within the filled polymer films was found to depend on the sol-gel content during synthesis. Grazing incidence small angle X-ray scattering and scanning electron microscopy imaging proved that well-ordered structures were created over large areas of the thin hybrid film

  10. Improved photocatalytic activity of zeolite- and silica-incorporated TiO2 film.

    Science.gov (United States)

    Tanaka, K; Fukuyoshi, J; Segawa, H; Yoshida, K

    2006-09-21

    Porous TiO2 film was prepared by sol-gel method from TiO2 sol containing polyvinylpyrolidone (PVP). Photocatalytic activity of the film was evaluated by the elimination rate of ethylene. Several adsorbents including zeolite and silica powders were incorporated into the TiO2 film. All the adsorbents enhanced the activity. The optimum adsorbent content was 0.005-0.01 g/ml of the coating sol solution. Silica provided better activity than zeolite. At high humidity and in dry air the activity decreased. PMID:16704899

  11. Dye-Sensitized Nanostructured TiO2 Film Based Photoconductor

    OpenAIRE

    Kallioinen, Jani; Hassan, M.R.; Paraoanu, G. S.; Korppi-Tommola, Jouko

    2008-01-01

    Grooves were etched in a conductive layer of a conductive, transparent glass, and a nanoporous TiO2 film was deposited on both the conductive and nonconductive area. The width of the grooves was 100 $\\mu$m and 150 $\\mu$m. A transparent TiO2 film was dye-sensitized, covered with an electrolyte, and sandwiched with a cover glass. The conductivity of the dye-sensitized TiO2 film permeated with electrolyte was studied in the dark and under illumination, and was observed to be de...

  12. Photocatalytic characteristics of TiO2 films deposited by magnetron sputtering on polycarbonate at room temperature

    International Nuclear Information System (INIS)

    Anatase TiO2 thin films were successfully grown at room temperature on polycarbonate substrates, using RF magnetron sputtering under various conditions. The deposition parameters used to examine the photocatalytic activity of TiO2 films included RF power, sputtering pressure, argon/oxygen ratio (O2/(Ar + O2)) and deposition time. An orthogonal array and analysis of variance (ANOVA) were used to determine the performance of the deposition process. The effects of the deposition parameters on the structure, morphology and photocatalytic performance of TiO2 films were analyzed using scanning electron microscopy (SEM), X-ray diffraction, a contact angle meter and UV/vis/NIR spectroscopy. The RF power was found to be the factor that most affected the water droplet contact angle and the sputtering pressure was found to be the second ranking factor. The results indicate that the photocatalytic performance is improved by increasing RF power, but an increase in sputtering pressure has an adverse effect. Higher photocatalytic activity is achieved for TiO2 films using an RF power of 210 W, sputtering pressure of 0.93 Pa, argon/oxygen ratio of 30% and a deposition time of 2 h.

  13. Photocatalytic characteristics of TiO2 films deposited by magnetron sputtering on polycarbonate at room temperature

    Science.gov (United States)

    Kuo, C. G.; Hsu, C. Y.; Wang, S. S.; Wen, D. C.

    2012-07-01

    Anatase TiO2 thin films were successfully grown at room temperature on polycarbonate substrates, using RF magnetron sputtering under various conditions. The deposition parameters used to examine the photocatalytic activity of TiO2 films included RF power, sputtering pressure, argon/oxygen ratio (O2/(Ar + O2)) and deposition time. An orthogonal array and analysis of variance (ANOVA) were used to determine the performance of the deposition process. The effects of the deposition parameters on the structure, morphology and photocatalytic performance of TiO2 films were analyzed using scanning electron microscopy (SEM), X-ray diffraction, a contact angle meter and UV/vis/NIR spectroscopy. The RF power was found to be the factor that most affected the water droplet contact angle and the sputtering pressure was found to be the second ranking factor. The results indicate that the photocatalytic performance is improved by increasing RF power, but an increase in sputtering pressure has an adverse effect. Higher photocatalytic activity is achieved for TiO2 films using an RF power of 210 W, sputtering pressure of 0.93 Pa, argon/oxygen ratio of 30% and a deposition time of 2 h.

  14. Impact of Thickness of Columnar Crystal TiO2 Film on Photocatalytic Activity of FTO/TiO2 Coated Glass

    Directory of Open Access Journals (Sweden)

    TENG Fan, LIU Yong, GE Yan-Kai, ZHANG Rui-Shuo, SONG Chen-Lu, HAN Gao-Rong

    2012-06-01

    Full Text Available Columnar crystal structured TiO2 thin films were prepared on the FTO (SnO2: F) low―emissivity coated glass substrates, obtaining double―layer structure FTO/TiO2 coated glass samples. The effect of TiO2 film thickness on the photocatalytic activity, the low―emissivity performance and light transmission properties of the FTO/TiO2 coated glass samples was investigated. The results showed that the photocatalytic activity of the samples increased firstly and then decrease with the increase of the film thickness. The best catalytic activity was observed for the sample coated with 300 nm TiO2 film. The low―emissivity properties of the samples declined as the TiO2 film thickness increased. The sample still have some low―emissivity performance when the TiO2 film thickness is 300 nm, while the light transmittance of the samples have little relations with the TiO2 films thickness. The visible light transmittances of the samples remain at about 72% with a smooth surface. The average surface roughness of the sample is about 1 nm. The FTO/TiO2 coated glass has photocatalytic self―cleaning properties with excellent low emissive performance and light transmittance property, thus guaranteeing good application prospects.

  15. Photoelectrochemical activity of liquid phase deposited TiO2 film for degradation of benzotriazole

    International Nuclear Information System (INIS)

    TiO2 film deposited on glassy carbon electrode surface was prepared via the liquid phase deposition (LPD). The deposited TiO2 film before and after calcination was characterized with scanning electron microscopy (SEM) and X-ray diffraction (XRD). Based on the high photoelectrochemical activity of calcined LPD TiO2 film, the photoelectrocatalytic degradation of benzotriazole (BTA) was investigated. Compared with the electrochemical oxidation process, direct photolysis or photocatalysis for treatment of BTA, a synergetic photoelectrocatalytic degradation effect was observed using the LPD TiO2 film-coated electrode. Various factors influencing the photoelectrocatalytic degradation of BTA such as film calcination, applied bias potential, pH value, supporting electrolyte concentration and initial concentration of BTA were investigated. The COD removal for BTA solution was analyzed to evaluate the mineralization of the PEC process. Based on the degradation experimental results, a possible photoelectrocatalytic degradation mechanism for BTA was proposed.

  16. Preparation and characterization of polyvinyl alcohol films containing TiO2 nanoparticles

    International Nuclear Information System (INIS)

    Polyvinyl alcohol films (PVA) doped with nanoparticles of TiO2 were prepared and characterized. These materials were obtained from a suspension of nanoparticles of TiO2 and PVA in 10% aqueous solution, and stabilized by ultrasound. The films of PVA-TiO2 (10, 100 and 1000 ppm of TiO2), of approximately 100?m of thickness, were prepared by pouring the mixture on glass plates and drying at room temperature by 48 h. These films were characterized by infrared spectroscopy (FT-IR) and UV-visible. No evidence of interaction between the chains of PVA and TiO2 was found. The dispersion of the TiO2 in the polymeric matrix was evaluated using the scanning electron microscopy (SEM). In spite of the treatment by ultrasound, the films show TiO2 agglomerates of different sizes. These films have better mechanical properties. It was observed an increase of the Young modulus as a function of the TiO2 concentration. Simultaneously the elongation of breakage diminishes. Nevertheless, significant changes in the tensile strength were not observed. (author)

  17. SAXS Studies of TiO2 Nanoparticles in Polymer Electrolytes and in Nanostructured Films

    Directory of Open Access Journals (Sweden)

    Sigrid Bernstorff

    2010-11-01

    Full Text Available Polymer electrolytes as nanostructured materials are very attractive components for batteries and opto-electronic devices. (PEO8ZnCl2 polymer electrolytes were prepared from PEO and ZnCl2. The nanocomposites (PEO8ZnCl2/TiO2 themselves contained TiO2 nanograins. In this work, the influence of the TiO2 nanograins on the morphology and ionic conductivity of the nanocomposite was systematically studied by transmission small-angle X-ray scattering (SAXS simultaneously recorded with wide-angle X-ray diffraction (WAXD and differential scanning calorimetry (DSC at the synchrotron ELETTRA. Films containing nanosized grains of titanium dioxide (TiO2 are widely used in the research of optical and photovoltaic devices. The TiO2 films, prepared by chemical vapor deposition and e-beam epitaxy, were annealed in hydrogen atmospheres in the temperature range between 20 °C and 900 °C in order to study anatase-rutile phase transition at 740 °C. Also, grazing-incidence small angle X-ray scattering (GISAXS spectra for each TiO2 film were measured in reflection geometry at different grazing incident angles. Environmentally friendly galvanic cells, as well as solar cells of the second generation, are to be constructed with TiO2 film as working electrode, and nanocomposite polymer as electrolyte.

  18. Blister formation in rutile TiO 2(1 0 0) films by helium irradiation

    Science.gov (United States)

    Yamamoto, S.; Nagata, S.; Takayama, A.; Yoshikawa, M.

    2006-08-01

    Incident energy, fluence of helium ion and temperature for blister formation in rutile TiO 2(1 0 0) films were investigated. Epitaxial rutile TiO 2(1 0 0) films were grown on ?-Al 2O 3(0 0 0 1) substrates by pulsed laser deposition. The films were irradiated at room temperature and 95 K with 4 keV helium ions up to fluence range from 1.0 × 10 16 to 2.3 × 10 17 ions/cm 2. The surface morphology of TiO 2 films was observed by scanning electron microscope and atomic force microscope. Rutherford backscattering spectroscopy with channeling was used to determine the depth profile of radiation-induced damage. In the case of room temperature irradiation with fluences higher than 2 × 10 16 ions/cm 2, helium blisters with 100-200 nm sizes in TiO 2 films were observed. Furthermore, helium irradiation at 95 K resulted in smaller size blisters (˜50 nm). It is suggested that the size of blisters in TiO 2(1 0 0) films is strongly affected by the temperature during the helium irradiation. The photo-induced superhydrophilicity of TiO 2 films was improved by high fluence helium irradiation, which caused blister growth.

  19. Blister formation in rutile TiO2(1 0 0) films by helium irradiation

    International Nuclear Information System (INIS)

    Incident energy, fluence of helium ion and temperature for blister formation in rutile TiO2(1 0 0) films were investigated. Epitaxial rutile TiO2(1 0 0) films were grown on ?-Al2O3(0 0 0 1) substrates by pulsed laser deposition. The films were irradiated at room temperature and 95 K with 4 keV helium ions up to fluence range from 1.0 x 1016 to 2.3 x 1017 ions/cm2. The surface morphology of TiO2 films was observed by scanning electron microscope and atomic force microscope. Rutherford backscattering spectroscopy with channeling was used to determine the depth profile of radiation-induced damage. In the case of room temperature irradiation with fluences higher than 2 x 1016 ions/cm2, helium blisters with 100-200 nm sizes in TiO2 films were observed. Furthermore, helium irradiation at 95 K resulted in smaller size blisters (?50 nm). It is suggested that the size of blisters in TiO2(1 0 0) films is strongly affected by the temperature during the helium irradiation. The photo-induced superhydrophilicity of TiO2 films was improved by high fluence helium irradiation, which caused blister growth

  20. Composite films of polycations and TiO2 nanoparticles with photoinduced superhydrophilicity.

    Science.gov (United States)

    Laugel, Nicolas; Hemmerlé, Joseph; Ladhari, Nadia; Arntz, Youri; Gonthier, Eric; Haikel, Youssef; Voegel, Jean-Claude; Schaaf, Pierre; Ball, Vincent

    2008-08-01

    We apply herein the reactive layer-by-layer (LBL) spray deposition of a polycation (polyethyleneimine, PEI) and a water soluble initiator of titanium dioxide [Ti(IV) bis(ammoniumlactato)dihydroxide, TiBisLac] to produce thin hybrid films containing PEI and nearly monodisperse TiO(2) anatase nanoparticles. The thickness of these coatings can be finely adjusted by either changing the number of deposition steps or the TiBisLac concentration. These films display intense absorption in the UV range and nearly full transparency above 365 nm and they also display photoinduced superhydrophilicity. These coatings can be produced either by reactive LBL spray deposition or reactive LBL dipping and may offer a wide range of applications from biology, as antibacterial coatings, to photoactive materials. PMID:18514216

  1. Investigations on TIO2 and AG based single and multilayer films for window glazings

    OpenAIRE

    M.M. Hasan; A. B. M. Malek; Haseeb, A. S. M. A.; Masjuki, H. H.

    2010-01-01

    In this investigation, TiO2 and Ag based single and multilayer-films were deposited on microscope glass slides with varying individual layer thicknesses by radio-frequency reactive magnetron sputtering. Prior to multilayer development, single layers of Ag and TiO2 were deposited and characterized. All the films were prepared at an elevated pressure of 3 Pa at room temperature. It was found that single layer of TiO2 showed anatase polycrystalline structure. It also exhibited high visible trans...

  2. Characterization of nano porous TiO2 films prepared by sol-gel method

    International Nuclear Information System (INIS)

    Nano-porous TiO2 films as a key component in dye sensitized and extremely thin absorber (ETA) solar cells were prepared by the sol-gel method using spin-coating and spray pyrolysis deposition techniques. The precursor sol contained titanium (IV) iso-prop-oxide, acetylacetone and polyethylene glycol (PEG) in ethanol. Glass and n-type Si (100) were used as substrates. SEM, XRD and FT-IR were used to study the effect of the PEG concentration in the precursor solution as well as different annealing routes on the film composition and structural properties. Crystalline films with anatase structure could be grown by the spray technique at 500 C. Post-annealing at 500 C increases the crystallite size (from 5 to 9 nm) and results in an average pore size around 40 nm. A film thickness of about 2.3 ?m is attained using 50 spray pulses. In spin coated films the formation of Ti-O-Ti anatase bonds is observed after annealing at 450 C. Crystalline films can be prepared by annealing at temperatures above 700 C. Surface morphology and pore size of spin coated films are controlled by the amount of PEG in the sol. The film thickness is around 120 nm after three coating cycles. (authors)

  3. Photo-oxidative degradation of TiO2/polypropylene films

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Photo-oxidative degradation of polypropylene is accelerated by TiO2 incorporation. • Weight loss, FTIR, SEM and GPC shown high degree of degradation of polypropylene. • A mechanism of the photo-degradation of polypropylene by TiO2 is proposed. - Abstract: Photo-oxidative degradation of polypropylene films with TiO2 nanoparticles incorporated was studied in a chamber of weathering with Xenon lamps as irradiation source. TiO2 powder with crystalline structure of anatase was synthesized by thermal treatments at 400 and 500 °C starting from a precursor material obtained by sol–gel method. Composites of TiO2/polypropylene were prepared with 0.1, 0.5 and 1.0 wt% of TiO2. The mixture of components was performed using a twin screw extruder, the resulting material was pelletized by mechanical fragmenting and then hot-pressed in order to form polypropylene films with TiO2 dispersed homogeneously. Photo-oxidative degradation process was followed by visual inspection, weight loss of films, scanning electron microscopy (SEM), infrared spectroscopy with Fourier transformed (FTIR), and gel permeation chromatography (GPC)

  4. Transferrable superhydrophobic TiO2 nanorods on reduced graphene oxide films using block copolymer templates

    Science.gov (United States)

    Seo, Myung-Seok; Kim, Jin-Hyung; Kim, Sung-Soo; Kang, Heejung; Sohn, Byeong-Hyeok

    2015-04-01

    Superhydrophobic surfaces are normally fixed on the chosen materials. Here, we report transferrable superhydrophobicity which was enabled by fabricating TiO2 nanorods on a reduced graphene oxide (rGO) film. Superhydrophobic TiO2 nanorods were first synthesized from a nanoporous template of block copolymers (BCPs). The controllability over the dimension and shape of nanopores of the BCP template allowed for the adjustment of TiO2 nanostructures for superhydrophobicity. Since the rGO film provided effective transferring, TiO2 nanorods were conveyed onto a flexible polymer film and a metal substrate. Thus, the surface of the designated substrate was successfully changed to a superhydrophobic surface without alteration of its inherent characteristics.

  5. Polymer Photovoltaic Cell Using TiO2/G-PEDOT Nanocomplex Film as Electrode

    Directory of Open Access Journals (Sweden)

    2009-03-01

    Full Text Available Using TiO2/G-PEDOT (PEDOT/PSS doped with glycerol nanocomplex film as a substitute for metal electrode in organic photovoltaic cell is described. Indium tin oxide (ITO worked as cathode and TiO2/G-PEDOT nanocomplex works as anode. The thickness of TiO2 layer in nanocomplex greatly affects the act of this nonmetallic electrode of the device. To enhance its performance, this inverted organic photovoltaic cell uses another TiO2 layer as electron selective layer contacted to ITO coated glass substrates. All films made by solution processing techniques are coated on the transparent substrate (glass with a conducting film ITO. The efficiency of this solar cell is compared with the conventional device using Al as electrode.

  6. Preparation of TiO2/SiO(x) double-layer films on glass beads and its application to NO and SO2 removal.

    Science.gov (United States)

    Pham, Hung-Cuong; Kim, Kyo-Seon

    2013-08-01

    Glass beads were coated with SiO(x) thin film as the first layer and with TiO2 thin film as the second layer by a rotating cylindrical PCVD reactor. The thicknesses of TiO2/SiO(x) double-layer films were measured by scanning electron microscopy. Glass beads coated with TiO2/SiO(x) double-layer films were packed inside the cylindrical reactor. NO and SO2 removal by dielectric barrier discharge-photocatalyst (DBD-P) hybrid process was tested for various conditions of process variables. The NO and SO2 removal efficiencies were improved by using a combination of dielectric barrier discharge and photodegradation by TiO2/SiO(x) double-layer films. The stronger the applied voltage is, the higher the pulse frequency is, or the longer the gas residence time is, the higher the NO and SO2 removal efficiencies become. In this study, we found that the glass beads coated with TiO2/SiO(x) double-layer films by a rotating cylindrical PCVD reactor could be used effectively to remove NO and SO2 by DBD-P hybrid process. PMID:23882796

  7. Graphene incorporated nanocrystalline TiO2 films for the photocathodic protection of 304 stainless steel

    International Nuclear Information System (INIS)

    Composite films of TiO2 and graphene (GR) were prepared on 304 stainless steel (304SS) by the sol–gel method and heat treatment. The morphology, crystalline phase, and composition of the GR/TiO2 films were characterized systematically by X-ray diffraction, Raman spectroscopy and scanning electron microscopy, respectively. The photocathodic protection performances of the composite film under illumination and dark conditions in 3.0% NaCl solution were evaluated through the electrochemical measurements. It is indicated that the incorporation of GR in TiO2 film can improve effectively the photocathodic protection effect for 304SS under the UV illumination. Compared to 350 mV of pure TiO2 film, the electrode potentials can be negatively shifted to about ?600 mV under UV light irradiation by incorporating GR into TiO2 films. At the same time, a 14-fold photocurrent density can be obtained for the GR/TiO2 film. This indicates that GR can play an excellent enhancing effect on the photogenerated cathodic protection of TiO2 films.

  8. Liquid phase deposition of mesoporous TiO2/DNA hybrid film: Characterization and photoelectrochemical investigation

    International Nuclear Information System (INIS)

    A photoelectroactive TiO2/DNA hybrid film was synthesized via the liquid phase deposition (LPD) process. Scanning electron microscopic (SEM) characterization showed that the compact TiO2 film was changed to a mesoporous structure when DNA was present in the deposition solution, which might be the result of TiO2 particles growing along the backbones of the double-helical structure of DNA molecules. Although UV absorption spectra and cyclic voltammograms indicated that the deposited TiO2 on the substrate surface was decreased in the presence of DNA, an enhanced photocurrent response was observed. The electrochemical impedance and cyclic voltammetric measurements using K3[Fe(CN)6] as a redox probe suggested that the mesoporous film provided a relatively more efficient electron transfer interface, which could improve the photoelectron transfer rate from the semiconducting film to the electrode and reduce the recombination of photoelectrons and holes. This results in an enhanced photocurrent. Even after long-term and continuous UV irradiation, the mesoporous film exhibited a promoted photoelectrochemical response. The promoted photoelectrocatalytic degradation of methylene blue was obtained on the TiO2/DNA composite film, which is consistent with the enhanced photocurrent, and this demonstrates that DNA behaved as a useful biomaterial for the synthesis of a photoelectroactive hybrid film with impra photoelectroactive hybrid film with improved performance.

  9. Anatase TiO2 sols derived from peroxotitanium acid and to form transparent TiO2 compact film for dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Graphical abstract: Dye-sensitized solar cells with TiO2 nanocrystalline porous film in absence of compact film (A) and in presence of compact film in thickness of 1.0 ?m (B), 2.5 ?m (C), 4.0 ?m (D), respectively. Highlights: ? Anatase TiO2 sols were prepared by the hydrothermal treatment of peroxotitanium acid. ? TiO2 sols were used for DSSC photoelectrode as the compact film on FTO layer. ? The transmittance of the TiO2 compact film on FTO reached 80%. ? The ? of DSSCs in the presence of the compact film has improved significantly from 4.2% to 5.6%. - Abstract: Transparent and surfactant-free TiO2 sols containing anatase nanocrystals were prepared by the hydrothermal treatment of water-soluble peroxotitanium acid (PTA) at a temperature of 120 deg. C. The TiO2 nanocrystals were characterized by transmission electron microscopy (TEM). The TEM results indicated that the TiO2 nanocrystals were nanorod-like with diameters of less than 7 nm after the subsequently hydrothermal treatment. A gradient layer between the transparent fluorine doped SnO2 (FTO) layer and the porous titanium dioxide nanocrystalline film for dye-sensitized solar cells (DSSCs) photoelectrodes, was made with the as-prepared TiO2 sols. The TiO2 gradient layers were characterized by field-emission scanning electron microscopy and UV-vis absorption spectrometry. After the gradient layometry. After the gradient layer deposition on the FTO coated glass, the composite multilayer film exhibited the visible light transmittance of 80% which approached to that of bare FTO glass. The photo-to-electric energy conversion efficiency of the N719 dye-sensitized solar cell had significantly improved from 4.2% to 5.6% in the presence of the compact layer between FTO and the porous TiO2 nanocrystalline film under of AM1.5 illumination (100 mW/cm2). The remarkable improvements in short-circuit current for the DSSCs was due to the effective gradient layer at the FTO-TiO2 interface which prevented direct contact of electrolytes with FTO and consequently reduced charge recombination losses.

  10. Anatase and rutile TiO2 films deposited by arc-free deep oscillation magnetron sputtering

    International Nuclear Information System (INIS)

    Phase control of TiO2 films at low deposition temperatures is important for many applications. In this study, nanocrystalline TiO2 films were synthesized on glass and steel substrates in a balanced magnetron sputtering system using the new deep oscillation magnetron sputtering (DOMS) and pulsed dc magnetron sputtering (PDCMS) techniques. A virtually arc-free high-power pulsed magnetron sputtering process for TiO2 reactive sputtering was observed for DOMS. No external substrate bias and heating were used for the depositions. For the DOMS TiO2 depositions, different peak target currents (powers) were used. The crystal phase and microstructure of the TiO2 films were characterized and compared. It was found that the TiO2 films deposited by PDCMS exhibited a complete anatase phase. The TiO2 films deposited by DOMS at a low target peak current (e.g. 50 A) also contained mainly the anatase phase. Nevertheless, an increase in the peak target current for the DOMS deposition promoted the formation of the rutile phase, increased the density and decreased the grain size of the TiO2 films. A complete rutile phase was obtained for the TiO2 film deposited by DOMS at a high target peak current (200 A). The mechanical and optical properties of the anatase and rutile TiO2 films were also studied and compared. (paper)

  11. The effect of multiwalled carbon nanotube doping on the CO gas sensitivity of TiO2 xerogel composite film

    Science.gov (United States)

    Lee, Jin-Seok; Ha, Tae-Jung; Hong, Min-Hee; Park, Chang-Sun; Park, Hyung-Ho

    2013-03-01

    A simple sol-gel method was applied for the synthesis of 0.01 wt% multiwalled carbon nanotubes (MWCNTs)-doped TiO2 xerogel composite film. The film's CO gas sensing properties were then evaluated. Doped MWCNTs were coated with TiO2 and distributed on a TiO2 xerogel matrix. The TiO2 xerogel showed an anatase structure after heat treatment at 450 °C under vacuum. The specific surface area of the composite material was larger than the pure TiO2 xerogel material. The CO gas sensitivity of the MWCNTs(0.01 wt%)-doped TiO2 xerogel composite film was found to be seven times higher than that of pure TiO2 xerogel film and to have good stability. This higher gas-sensing property of the composite film was due to both an increase of specific surface area and the n-p junction structure of the TiO2 xerogel coated on MWCNTs. The electrons generated from TiO2 after adsorption of CO gas induces electron transfer from the TiO2 to the MWCNTs. This induces a characteristic change in the MWCNTs from p-type to n-type, and the resistance of MWCNTs-doped TiO2 xerogel composite sensor is therefore decreased.

  12. Electrochromic multilayer films with enhanced stability based on polyoxometalate and TiO2

    International Nuclear Information System (INIS)

    Electrochromic multilayer films consisting of polyoxometalate (POM) cluster K6[P2W18].14H2O (P2W18), TiO2 and polyallylamine hydrochloride (PAH) were fabricated on quartz, silicon wafer and ITO substrates by the layer-by-layer self-assembly method. The multilayer films were characterized by UV-vis spectrum, scanning electron microscopy (SEM), cyclic voltammetry (CV) and chronoamperometric (CA) and in situ spectral electrochemical measurements. The interesting feature is that the electrochromic films can increase stability due to the presence of TiO2. The multilayer films exhibit high optical contrast, suitable response time and low operation potential. TiO2 is employed to enhance stability of the electrochromic multilayer films based on POMs by the layer-by-layer method, which gives valuable information for exploring new stable electrochromic materials.

  13. Characterization of sulfur-doped TiO2 films by RBS/C

    International Nuclear Information System (INIS)

    Sulfur-doped titanium dioxide (TiO2) films have been deposited on ?-Al2O3(0 0 0 1) and Si(1 0 0) substrates by pulsed laser deposition (PLD). To investigate growth condition of sulfur-doped TiO2 films, the various concentration of sulfur in titanium dioxide targets was prepared by annealing titanium disulfide (TiS2) in air up to 400 deg. C. The crystal structure of films and the concentration of doped sulfur were assessed by X-ray diffraction (XRD) and Rutherford backscattering spectroscopy with channeling (RBS/C). It was found that the concentration of sulfur in rutile TiO2 films was mainly influenced by the substrate temperature. Rutile TiO2(1 0 0) films contained a few atomic percent sulfur were obtained on ?-Al2O3(0 0 0 1) at 400 deg. C substrate temperature using an annealed titanium disulfide target. RBS/C analysis showed that doped sulfur atoms in rutile TiO2(1 0 0) films were distributed randomly

  14. Optical Study of Ultrathin TiO2 Films for Photovoltaic and Gas Sensing Applications

    Directory of Open Access Journals (Sweden)

    Arturas SUCHODOLSKIS

    2014-06-01

    Full Text Available TiO2 ultrathin films of thickness below 20 nm were deposited by reactive RF magnetron sputtering. The optical properties of TiO2 films were investigated by various optical techniques including UV-VIS-NIR spectroscopic ellipsometry. The Scanning Probe Microscopy (SPM was used to determine thickness and surface roughness of the deposited films. The correlation between preparation conditions of ultrathin TiO2 films and their physical properties has been studied. The analysis of optical data revealed the parameters of deposited films and intrinsic properties of TiO2 material before and after annealing. We found that deposited layers were predominantly amorphous with high porosity at the top sample, and absence of porosity at the bottom of TiO2 layer. Annealing considerably improves structural order of the studied samples and the film transforms to the polycrystalline anatase phase. Also we evaluated the energy bandgap (about 3.1 eV – 3.2 eV which increases after annealing (above 3.3 eV and it is  close to the bandgap of anatase. DOI: http://dx.doi.org/10.5755/j01.ms.20.2.6328

  15. Polyvinyl pyrrolidone aided preparation of TiO2 films used in flexible dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Highlights: · Polyvinyl pyrrolidone (PVP) is used to low temperature prepare TiO2 film in flexible DSSC. · PVP improves TiO2 dispersion, adherence to flexible substrate and dye adsorption. · Ultraviolet light irradiation improve the surface state of TiO2 film. · Resultant flexible DSSC achieves a light-to-electric conversion efficiency of 3.02%. - Abstract: Polyvinyl pyrrolidone (PVP) is introduced to low temperature preparation of a good quality TiO2 film used in flexible dye-sensitized solar cells (DSSCs). The samples are characterized by scanning electron microscopy and UV-vis absorption spectra, the photovoltaic performance of the DSSC is measured. It is found that PVP can improve the dispersion of TiO2 particles and the adherence of TiO2 particles to flexible substrate, as well as the adsorption of sensitized dye to TiO2 film. Additionally, ultraviolet light irradiation can eliminate organics remained on the surface the TiO2 film and improve the surface state of TiO2 film. Under an optimal condition, a flexible DSSC using TiO2 film doped PVP and UV irradiation treated achieves a light-to-electric energy conversion efficiency of 3.02% under irradiation with a simulate solar light intensity of 100 mW cm-2.

  16. Polycrystalline TiO2 (B) Nanosheet Films Deposited via Langmuir-Blodgett Method

    Science.gov (United States)

    Biedermann, Laura; Kotula, Paul; Beechem, Thomas; Dylla, Anthony; Stevenson, Keith; Chan, Calvin

    2014-03-01

    As an energy storage material, TiO2 offers higher Li+ capacities and smaller volume changes with lithiation than graphite electrodes. In particular, the bronze phase, TiO2(B) has a higher lithiation capacity (1.0 Li+/Ti) and faster lithiation kinetics due to its larger lattice parameters than other TiO2 polymorphs. Direct observation of lithiation will require TiO2(B) monolayers, such as those prepared via Langmuir-Blodgett deposition of the nanosheets (NS). Optical microscopy of the TiO2(B)-NS Langmuir monolayer at the air/water interface shows that these nanosheets assemble into large (>1 mm) islands. These elastic TiO2(B)-NS monolayers are deposited on diverse substrates for further characterization. Electron diffraction in both transmission electron microscopy (TEM) and low-energy electron microscopy (LEEM) of these films confirm that their polycrystalline structure is predominately composed of TiO2(B) nanocrystals, ~10s nm across. Discrimination of monolayer and bilayer TiO2(B) is evident in LEEM. Thermal stability of these nanosheets is investigated via in-situ TEM and ex-situ Raman spectroscopy. This monolayer TiO2(B) deposition will allow future observations of lithiation and phase changes. As an energy storage material, TiO2 offers higher Li+ capacities and smaller volume changes with lithiation than graphite electrodes. In particular, the bronze phase, TiO2(B) has a higher lithiation capacity (1.0 Li+/Ti) and faster lithiation kinetics due to its larger lattice parameters than other TiO2 polymorphs. Direct observation of lithiation will require TiO2(B) monolayers, such as those prepared via Langmuir-Blodgett deposition of the nanosheets (NS). Optical microscopy of the TiO2(B)-NS Langmuir monolayer at the air/water interface shows that these nanosheets assemble into large (>1 mm) islands. These elastic TiO2(B)-NS monolayers are deposited on diverse substrates for further characterization. Electron diffraction in both transmission electron microscopy (TEM) and low-energy electron microscopy (LEEM) of these films confirm that their polycrystalline structure is predominately composed of TiO2(B) nanocrystals, ~10s nm across. Discrimination of monolayer and bilayer TiO2(B) is evident in LEEM. Thermal stability of these nanosheets is investigated via in-situ TEM and ex-situ Raman spectroscopy. This monolayer TiO2(B) deposition will allow future observations of lithiation and phase changes. Sandia is managed by Sandia Corp., a subsidiary Lockheed Martin, for the U.S. DOE NNSA (DE-AC04-94AL85000). Work was supported by an U.S. DOE BES EFRC (DE-SC0001091).

  17. Preparation of Ordered Porous TiO2 Film from Honeycomb Structured TBT/PMMA Hybrid Film

    Directory of Open Access Journals (Sweden)

    SHEN Yan-Ming, LIU Dan, WU Jing, LIU Ya-Qi, JI Sheng-Fei, LI Tian-Shu

    2010-07-01

    Full Text Available TBT/PMMA organic-inorganic hybrid honeycomb patterned film was prepared by Breath Figures method, then it was suffered vapor phase hydrothermal treatment and transformed into ordered porous TiO2 film via pyrolysis process. The hole structure was investigated during the vapor phase hydrothermal treatment and pyrolysis process. The results show that, during the vapor phase hydrothermal treatment, TBT hydrolyzes to titanium hydrogen oxide hydrates, forming the strongerTiOnetworks, which therefore prevents the PMMA from liquefied in the pyrolysis process, as a result the ordered porous TiO2 film is obtained. Compared with non-hydrothermal treated TiO2 film, the resulted ordered porous TiO2 film enhances the photoelectrochemical response and its photocurrent density is increased by 3 times under UV light irradiation.

  18. The influence of metal interlayers on the structural and optical properties of nano-crystalline TiO2 films

    International Nuclear Information System (INIS)

    TiO2-M-TiO2 (M = W, Co and Ag) multilayer films have been deposited on glass substrates using reactive magnetron sputtering, then annealed in air for 2 h at 500 °C. The structure, surface morphology and optical properties of the films have been studied using X-ray diffraction, Raman spectroscopy, atomic force microscopy and UV-vis spectroscopy. The TiO2-W-TiO2 and TiO2-Co-TiO2 films showed crystalline phases, whereas the TiO2-Ag-TiO2 films remained in the amorphous state. The crystallization temperature for the TiO2-M-TiO2 films decreased significantly compared with pure TiO2 film deposited on quartz. Detailed analysis of the Raman spectra suggested that the crystallization of TiO2-M-TiO2 films was associated with the large structural deformation imposed by the oxidation of intermediate metal layers. Moreover, the optical band gap of the films narrowed due to the appearance of impurity levels as the metal ions migrated into the TiO2 matrix. These results indicate that the insertion of intermediate metal layers provides a feasible access to improve the structural and optical properties of anatase TiO2 films, leading to promising applications in the field of photocatalysis.

  19. Photocatalytic properties of TiO2 films prepared by O2 cluster ion beam assisted deposition method

    International Nuclear Information System (INIS)

    Titanium dioxide (TiO2) films were prepared on Si(1 0 0) substrate by oxygen (O2) cluster ion beam assisted deposition method. The TiO2 films prepared at a substrate temperature of 200 deg. C or less were amorphous, whereas those at a substrate temperature of 300 deg. C contained both rutile and anatase. The refractive indexes of the TiO2 films increased with increasing substrate temperature. The surface state of the TiO2 film was smooth at an atomic level. The TiO2 films prepared at a substrate temperature of 300 deg. C showed high photocatalytic decomposition of methylene blue by ultraviolet (UV) irradiation, similar to those of TiO2(1 0 0) bulk state in a rutile structure. The contact angle of the TiO2 film with an initial value of 75 deg. decreased to 10 deg. by UV irradiation for 30 min, although that for TiO2(1 0 0) bulk state in rutile structure remained at the initial value even after the UV irradiation. It is considered that anatase in the TiO2 films was contributed to both photocatalytic decomposition and photocatalytic hydrophilicity of the films

  20. Influence of auxiliary plasma source on properties of photoactive TiO2 films by MePIII and D

    International Nuclear Information System (INIS)

    For several years, TiO2 is receiving increasing scientific attention as one of the most promising photo catalysts with a huge potential for solving several different types of environmental problems. While TiO2 powders and nanoparticles are well known and widely used, thin film surfaces are less investigated but still highly desired for applications. For TiO2 polymorphs, anatase powder is reported to be a more potent photo catalyst than rutile. Metal plasma immersion ion implantation and deposition is employed to form titanium oxide films at room temperature. By applying high voltage pulses of up to 5 kV at a duty cycle of 30%, polycrystalline films could be obtained. Additionally, an RF plasma source was used to increase the ionisation of the background oxygen gas at different flow rates, thus enhancing the ion bombardment of the surface. AFM, SEM, XRD and surface energy measurements show that by employing the auxiliary RF plasma source, a lower oxygen gas flux is compensated by increasing the oxygen content compared to the case without auxiliary plasma.

  1. Atomic force microscopy observation of TiO2 films deposited by dc reactive sputtering

    International Nuclear Information System (INIS)

    A bombardment of energetic particles such as secondary electrons and recoiled ions ejected from the target plane is a very useful technique for modifying the structure of the film in reactive sputtering. It leads to interesting effects such as enhancement of reactivity, adatom mobility, and atomic peening. Therefore, the state on the surface of the as-deposited film may significantly depend on the bombardment condition. So, in this study, the relationship between the bombardment condition and the surface morphology of TiO2 films has been investigated in detail. TiO2 films with a thickness of about 0.8-2.3 ?m were deposited by dc reactive sputtering on glass-slide substrates. The surface roughness of films was measured with atomic-force microscopy. The roughness parameter Ra on the surface of TiO2 films depended on the energy and the number of bombarding particles. After increasing the energy and the number of bombarding particles, Ra increased from 10 to 77 nm. Consequently, it was found that the surface morphology of TiO2 films strongly affected the plasma exposure to the growing film

  2. Atomic force microscopy observation of TiO2 films deposited by dc reactive sputtering

    Science.gov (United States)

    Takahashi, T.; Nakabayashi, H.; Terasawa, T.; Masugata, K.

    2002-07-01

    A bombardment of energetic particles such as secondary electrons and recoiled ions ejected from the target plane is a very useful technique for modifying the structure of the film in reactive sputtering. It leads to interesting effects such as enhancement of reactivity, adatom mobility, and atomic peening. Therefore, the state on the surface of the as-deposited film may significantly depend on the bombardment condition. So, in this study, the relationship between the bombardment condition and the surface morphology of TiO2 films has been investigated in detail. TiO2 films with a thickness of about 0.8-2.3 mum were deposited by dc reactive sputtering on glass-slide substrates. The surface roughness of films was measured with atomic-force microscopy. The roughness parameter Ra on the surface of TiO2 films depended on the energy and the number of bombarding particles. After increasing the energy and the number of bombarding particles, Ra increased from 10 to 77 nm. Consequently, it was found that the surface morphology of TiO2 films strongly affected the plasma exposure to the growing film. copyright 2002 American Vacuum Society.

  3. Mechanical properties and structure of TiO2 films deposited on quartz and silicon substrates.

    Czech Academy of Sciences Publication Activity Database

    Kulykovskyy, Valeriy; ?tvrtlík, R.; Vorlí?ek, Vladimír; Filip, J.; Bohá?, Petr; Jastrabík, L.

    2013-01-01

    Ro?. 542, Sept (2013), s. 91-99. ISSN 0040-6090 R&D Projects: GA ?R GAP108/12/1941; GA TA ?R TA03010743 Institutional support: RVO:68378271 Keywords : TiO2 film s * ion bombardment * film structure * nanoindentation * phase transformation Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.867, year: 2013

  4. Influences on photovoltage performance by interfacial modification of FTO/mesoporous TiO2 using ZnO and TiO2 as the compact film

    International Nuclear Information System (INIS)

    Highlights: ? ZnO has been introduced as the compact layer in dye-sensitized solar cells by a facile spin-coating method. ? The influences of ZnO and TiO2 compact films to photoelectron conversion process have been systematically investigated. ? The duel effect to photoelectron conversion process of ZnO compact film has been found. ? A new methodology of introducing an energy barrier at FTO/TiO2 interface rather than the surface of TiO2 electrode has been brought up. - Abstract: An effective ZnO compact film (ZCF) has been introduced at the interface of fluorine doped tin oxide (FTO) substrate and mesoporous TiO2 layer, and its effect on dye-sensitized solar cells (DSSCs) has been compared to that of conventional TiO2 compact film (TCF). The ZCF and TCF prepared by spin-coating method on FTO are characterized by energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), and UV-vis spectrophotometer. The existence of TiO2 can suppress the recombination occurring at the interface of FTO/electrolyte, resulting in a higher Jsc and Voc than bare FTO. The ZCF creates an energy barrier between FTO substrate and mesoporous TiO2 layer, which not only reduces the electron back transfer from FTO to I3- in the electrolyte, but also leads to the accumulation of photogenerated electrons, and increases the electron density in the condu the electron density in the conduction band of TiO2. The device based on FTO/ZCF substrate remarkably improves Voc and FF, finally increases energy conversion efficiency by 13.1% compared to the device based on bare FTO and 4.7% compared to the counterpart based on FTO/TCF.

  5. Sol-gel TiO2 films as NO2 gas sensors

    Science.gov (United States)

    Georgieva, V.; Gadjanova, V.; Grechnikov, A.; Donkov, N.; Sendova-Vassileva, M.; Stefanov, P.; Kirilov, R.

    2014-05-01

    TiO2 films were prepared by a sol-gel technique with commercial TiO2 powder as a source material (P25 Degussa AG). After a special treatment, printing paste was prepared. The TiO2 layers were formed by means of drop-coating on Si-control wafers and on the Au-electrodes of quartz resonators. The surface morphology of the films was examined by scanning electron microscopy (SEM). Their structure was studied by Raman spectroscopy and the surface composition was determined by X-ray photoelectron spectroscopy (XPS). The layers had a grain-like surface morphology and consisted mainly of anatase TiO2 phase. The sensitivity of the TiO2 films to NO2 was assessed by the quartz crystal microbalance (QCM) technique. To this end, the films were deposited on both sides of a 16-MHz QCM. The sensing characteristic of the TiO2-QCM structure was investigated by measuring the resonant frequency shift (?F) of the QCM due to the mass loading caused by NO2 adsorption. The Sauerbrey equation was applied to establish the correlation between the QCM frequency changes measured after exposure to different NO2 concentrations and the mass-loading of the QCM. The experiments were carried out in a dynamic mode on a special laboratory setup with complete control of the process parameters. The TiO2 films were tested in the NO2 concentration interval from 10 ppm to 5000 ppm. It was found that a TiO2 loading of the QCM by 5.76 kHz corresponded to a system sensitive to NO2 concentrations above 250 ppm. On the basis of the frequency-time characteristics (FTCs) measured, AF at different NO2 concentrations was defined, the adsorption/desorption cycles were studied and the response and recovery times were estimated. The results obtained show that the process is reversible in the NO2 interval investigated. The results further suggested that TiO2 films prepared by a sol-gel method on a QCM can be used as a sensor element for NO2 detection.

  6. Photocatalytic reduction of potassium chromate by Zn-doped TiO 2/Ti film catalyst

    Science.gov (United States)

    Yao, Zhongping; Jia, Fangzhou; Jiang, Yanli; Li, ChunXiang; Jiang, Zhaohua; Bai, Xuefeng

    2010-01-01

    The aim of this work was to investigate the photocatalytic (PC) reduction of potassium chromate by Zn-doped TiO 2/Ti film catalysts. The film catalyst was prepared by plasma electrolytic oxidation method in H 2SO 4 solution with different dosages of ZnSO 4. The composition and structure of the film catalysts was studied by XRD, SEM and EPMA. The removal rate of potassium chromate was investigated under the conditions of the different dosages of ZnSO 4 and the initial concentration of chromate potassium, and the reductive product during the PC reduction process was analyzed. The results showed that the film catalyst was composed of anatase TiO 2 and rutile TiO 2 with the porous structure. When the dosage of ZnSO 4 was 0.2 g/L, the film catalyst presented the highest catalytic activity, which related to the amount and the crystal grain size of anatase TiO 2 in the film. The PC reduction of potassium chromate by the film catalyst obeyed the pseudo-first-order kinetic equation. The UV-vis spectrum and XPS analyses proved that chromate Cr(VI) was reduced to Cr(III), which existed in the form of insoluble Cr(OH) 3.

  7. Photocatalytic degradation of benzene on zeolite-incorporated TiO2 film.

    Science.gov (United States)

    Hisanaga, Teruaki; Tanaka, Keiichi

    2002-08-01

    Zeolite powder was incorporated into the TiO2 film. Their photoactivities were evaluated for the gas phase degradation of benzene. Seven zeolite samples were used in this study and each enhanced the photocatalytic degradation. Humidity in the gas sample increased the degradation, but suppressed the adsorption of benzene to the TiO2 film. It was noted that the photoactivity was inversely proportional to the silica/alumina ratio of zeolite, whereas adsorption increased with this ratio. It was suggested that the adsorption of water onto zeolite contributes to the enhancement of benzene degradation. PMID:12137993

  8. Investigation of thermal diffusivity of nano-structured TiO2 films

    International Nuclear Information System (INIS)

    We investigate the thermal diffusivity of nano-structured TiO2 and TiO2 with 3% ZnFe2O4 ceramic films (nm films) sputtered on a cut Si substrates by using the Mirage effect method. Two series of films are prepared by the magneto-rf-spurt method. The investigation results show that: The thermal diffusivity of nano-structured film depends on the thickness of film and the annealing temperature. The thicker the film, the lower thermal diffusivity of the sample is. The value of thermal diffusivity increases with the increasing of the annealing temperature. It means that the thermal diffusivity depends on the phase structure of the film. The detail results, analyses and discussions will be presented in this paper

  9. Thermally induced crystallization of TiO2 and ZrO2 optical films

    International Nuclear Information System (INIS)

    Thin films of TiO2 and ZrO2 were produced by ion-beam sputter deposition onto fused silica and silicon substrates. Raman scattering and scanning electron microscopy (SEM) were used to monitor crystallization. After the amorphous titania films were deposited with high and low ion-beam current densities and by e-beam evaporation, and were thermally annealed, they showed evidence of crystallization in the vicinity of 300 to 3500C. When zirconia amorphous films of fused silica substrates were thermally annealed, they first crystallized into mixed tetragonal and monoclinic phases at 4500C. Further heating beyond 9000C showed a transformation to a mixed monoclinic and cubic phase. On silicon substrates, the lower temperature crystallization occurs near 7000C. At the same time, SEM micrographs revealed progressive structural changes form smooth, faint columns to larger grain columns at high annealing temperatures. The crystalline transformations in both oxides coincided with changes in refractive index, lowering of the optical band gap, and significant increases in optical absorption and scattering loss

  10. High rate deposition of photocatalytic TiO2 films by dc magnetron sputtering using a TiO2-x target

    International Nuclear Information System (INIS)

    Photocatalytic TiO2 films were deposited on glass substrates by dc magnetron sputtering using a slightly reduced TiO2-x target (2-x=1.986; conductivity, 3.7 S cm-1; density, 4.21 g/cm3). The variation in the deposition rate as a function of the O2 flow ratio did not show a hysteresis curve at the ''transition region'' as seen in the case of a Ti metal target. The deposition rate using the TiO2-x target in 100% Ar gas was approximately seven times higher than that using the Ti metal target in an 'oxide mode'. The films postannealed in air at temperatures ?200 deg. C showed excellent photodecomposition characteristics of acetaldehyde (CH3CHO) as well as photoinduced hydrophilicity

  11. Proliferation and differentiation of osteoblastic cells on silicon-doped TiO(2) film deposited by cathodic arc.

    Science.gov (United States)

    Wang, Bing; Sun, Junying; Qian, Shi; Liu, Xuanyong; Zhang, Shailin; Liu, Fei; Dong, Shengjie; Zha, Guochun

    2012-12-01

    This study aimed at the proliferation and differentiation of osteoblastic cells on silicon-doped TiO(2) and pure TiO(2) films prepared by cathodic arc deposition. The films were examined by X-ray photo-electron spectroscopy, which showed that silicon was successfully doped into the Si-TiO(2) film. Meanwhile, no significant difference was found between the surface morphology of silicon-doped TiO(2) and pure TiO(2) films. When osteoblastic cells were cultured on silicon-doped TiO(2) film, accelerated cell proliferation was observed. Furthermore, cell differentiation was evaluated using alkaline phosphatase (ALP), type I collagen (COL I) and osteocalcin (OC) as differentiation markers. It was found that ALP activity, the expression levels of OC gene, COL I gene and protein were up-regulated on silicon-doped TiO(2) film at 3 and 5 days of culture. Moreover, no significant difference was found in apoptosis between the cells cultured on silicon-doped TiO(2) and pure TiO(2) films. Therefore, findings from this study indicate that silicon-doped film favors osteoblastic proliferation and differentiation, and has the potential for surface modification of implants in the future. PMID:23089479

  12. Modification of TiO 2 photocatalytic films by V + ion implantation

    Science.gov (United States)

    Hou, Xing-Gang; Hao, Feng-Huan; Fan, Bin; Gu, Xue-Nan; Wu, Xian-Ying; Liu, An-Dong

    2006-01-01

    TiO 2 photocatalytic films produced by the sol-gel method were modified by vanadium ion implantation. The absorption edge of the modified films was broadened from UV to visible region. The photo-degradation of methyl orange (MO) in aqueous solutions catalyzed by these films was found to vary with the amounts of implanted vanadium ions. The maximum degradation of MO was found for a V + ion implantation fluence of 1 × 10 16 ions/cm 2.

  13. Modification of TiO2 photocatalytic films by V+ ion implantation

    International Nuclear Information System (INIS)

    TiO2 photocatalytic films produced by the sol-gel method were modified by vanadium ion implantation. The absorption edge of the modified films was broadened from UV to visible region. The photo-degradation of methyl orange (MO) in aqueous solutions catalyzed by these films was found to vary with the amounts of implanted vanadium ions. The maximum degradation of MO was found for a V+ ion implantation fluence of 1 x 1016 ions/cm2

  14. Synthesis of V-doped TiO2 films by chemical bath deposition and the effect of post-annealing on their properties

    International Nuclear Information System (INIS)

    Amorphous composite films, composed of a Ti1?xVxO2 solid-solution phase and a V2O5 phase, were produced by chemical bath deposition and subsequently air-annealed at various temperatures up to 550 °C. The microstructure and chemical composition of the as-prepared and annealed films were investigated by a combinatorial experimental approach using Scanning electron microscopy, X-ray powder diffraction and X-ray photoelectron spectroscopy. Ultraviolet–Visible Spectrometry was applied to determine the optical band gap of the as-prepared and annealed films. It followed that the incorporation of vanadium in the as-deposited films reduces the optical band gap of TiO2 from about 3.8 eV to 3.2 eV. Annealing of the films up to 350 °C leads to slight increase of band gap, as attributed to a reduction of the defect density in the initially amorphous oxide films due to the gradual development of long-range order and a concurrent reduction of the V4+-dopant concentration in the Ti1?xVxO2 solid-solution phase. The films crystallized upon annealing in air at 550 °C, which resulted in drastic changes of the phase constitution, optical absorbance and surface morphology. Due to the lower solubility of V4+ in crystalline TiO2, V4+ segregates out of the crystallizing Ti1?xVxO2 solid-solution phase, forming> solid-solution phase, forming crystalline V2O5 at the film surface. - Highlights: ? Incorporation of vanadium in TiO2 thin film reduces its optical band gap. ? Amorphous V-doped TiO2 and TiO2-V2O5 composite films were air-annealed up to 550ºC. ? Annealing of the films up to 350 °C leads to slight increase of the band gap.

  15. Transparent and conducting TiO2:Nb films made by sputter deposition : Application to spectrally selective solar reflectors

    OpenAIRE

    Maghanga, Christopher M.; Jensen, Jens; Niklasson, Gunnar A.; Granqvist, Claes-go?ran; Mwamburi, M.

    2010-01-01

    Transparent and conducting thin films of TiO2:Nb were prepared on glass and aluminum substrates by dual-target reactive DC magnetron sputtering in an Ar+O-2 plasma. The Nb content lay between 0 and 4.9 at% as determined by ion beam analyses. X-ray diffraction showed that vacuum annealing at 450 degrees C led to crystallinity and prevalence of the anatase phase. The influence of Nb doping was studied with regard to structural, optical, and electrical data. Optical constants were determined fro...

  16. Low-temperature sputtering of crystalline TiO2 films

    International Nuclear Information System (INIS)

    This article reports on the investigation of reactive magnetron sputtering of transparent, crystalline titanium dioxide films. The aim of this investigation is to determine a minimum substrate surface temperature Tsurf necessary to form crystalline TiO2 films with anatase structure. Films were prepared by dc pulsed reactive magnetron sputtering using a dual magnetron operating in bipolar mode and equipped with Ti(99.5) and ceramic Ti5O9 targets. The films were deposited on unheated glass substrates and their structure was characterized by x-ray diffraction and surface morphology by atomic force microscopy. Special attention is devoted to the measurement of Tsurf using thermostrips pasted to the glass substrate. It was found that (1) Tsurf is considerably higher (approximately by 100 deg. C or more) than the substrate temperature Ts measured by the thermocouple incorporated into the substrate holder and (2) Tsurf strongly depends on the substrate-to-target distance ds-t, the magnetron target power loading, and the thermal conductivity of the target and its cooling. The main result of this study is the finding that (1) the crystallization of sputtered TiO2 films depends not only on Tsurf but also on the total pressure pT of sputtering gas (Ar+O2), partial pressure of oxygen pO2, the film deposition rate a, the film deposition rate aD, and the film thickness h (2) crystalline TiO2 films with well developed anatase structure can be formed at Tsurf=160 deg. C and low values of aD?5 nm/min (3) the crystalline structure of TiO2 film gradually changes from (i) anatase through (ii) anatase+rutile mixture, and (iii) pure rutile to x-ray amorphous structure at Tsurf=160 deg. C and pT=0.75 Pa when pO2 decreases and aD increases above 5 nm/min, and (4) crystallinity of the TiO2 films decreases with decreasing h and Tsurf. Interrelationships between the structure of TiO2 film, its roughness, Tsurf, and aD are discussed in detail. Trends of next development are briefly outlined

  17. Variations in the structural, optical and electrochemical properties of CeO2-TiO2 films as a function of TiO2 content

    International Nuclear Information System (INIS)

    Alcohol based sols of cerium chloride (CeCl3.7H2O) and titanium propoxide (Ti(OPr)4) in ethanol mixed in different mole ratios have yielded mixed oxide films on densification at 500 deg. C. The reversibility of the intercalation/deintercalation reactions has shown electrochemical stability of the films. Addition of TiO2 in an equivalent mole ratio manifests in producing highly transparent films with appreciable ion storage capacity. The electrochemical studies have revealed the significant role of TiO2 in controlling the ion storage capacity of the films, as it tends to induce the disorder. In addition, the films prepared from an aged sol are observed to exhibit a much higher ion storage capacity than the films deposited using the as-prepared sol. The X-ray photoelectron spectroscopic studies have provided information on the variation of Ce4+/Ce3+ ratio as a function of increased TiO2 content in the films. This study has led to a better understanding of the increased ion storage capacity with the increased TiO2 proportion. The transmission electron microscopic study has demonstrated the presence of CeO2 nanograins even in films, which are amorphous to X-rays. Elucidation of the structural, optical and electrochemical features of the films has yielded information on aspects relevant to their usage in transmissive electrochromic devices. The films have been founochromic devices. The films have been found to exhibit properties that can find application as counter electrode in electrochromic smart windows in which they are able to retain their transparency under charge insertion, high enough for practical uses. Also, the fastest coloration-bleaching kinetics for the primary electrochromic electrode (WO3) working in combination with Ce/Ti (1:1) electrode stimulates the use of latter in electrochromic windows (ECWs)

  18. Investigations on TIO2 and AG based single and multilayer films for window glazings

    Directory of Open Access Journals (Sweden)

    M. M. Hasan

    2010-09-01

    Full Text Available In this investigation, TiO2 and Ag based single and multilayer-films were deposited on microscope glass slides with varying individual layer thicknesses by radio-frequency reactive magnetron sputtering. Prior to multilayer development, single layers of Ag and TiO2 were deposited and characterized. All the films were prepared at an elevated pressure of 3 Pa at room temperature. It was found that single layer of TiO2 showed anatase polycrystalline structure. It also exhibited high visible transmittance of above 80% and higher refractive index of 2.31 at a wavelength of 550 nm. The indirect optical band gap of the TiO2 films was estimated as 3.39 eV. The Ag single layer films were found to be crystalline with a very high reflectance for IR (Infra-red light. Finally, the multi-layers have been deposited and characterized by X-ray diffraction, UV-visible-NIR spectro-photometry, scanning electron microscopy and Auger electron spectroscopy.

  19. Nano-structure TiO2 film coating on 316L stainless steel via sol-gel technique for blood compatibility improvement

    OpenAIRE

    Mohammadreza Foruzanmehr; Seid Mohammad Hosainalipour; Shamsoddin Mirdamadi Tehrani; Mahnaz Aghaeipour

    2014-01-01

      Objective(s): Titanium oxides are known to be appropriate hemocompatible materials which are suggested as coatings for blood-contacting devices. Little is known about the influence of nanometric crystal structure, layer thickness, and semiconducting characteristics of TiO2 on blood hemostasis.   Materials and Methods: Having used sol-gel dip coating method in this study, TiO2 thin films were deposited on nano-scale electro-polished stainless steel 316L with 1 to 5 nano-sized layers. Surfa...

  20. The Photoelectrocatalytic Properties of Thin TiO2 Electode.

    Czech Academy of Sciences Publication Activity Database

    Morozová, Magdalena; Kluso?, Petr; Krýsa, J.; Šolcová, Olga

    Sofia : -, 2009 - (Petrova, G.; Vayssilov, G.), s. 138 ISBN 978-954-323-558-2. [International Symposium Advanced Micro- and Mesoporous Materials /3./. Albena (BG), 06.09.2009-09.09.2009] R&D Projects: GA ?R(CZ) GD203/08/H032; GA ?R GA104/09/0694 Institutional research plan: CEZ:AV0Z40720504 Keywords : photoelectrocatalysis * thin electrode * photoelectrochemical behavior Subject RIV: CC - Organic Chemistry http://bg-conferences.org/micro2009_new_1/

  1. IR and XPS investigation of visible-light photocatalysis-Nitrogen-carbon-doped TiO2 film

    International Nuclear Information System (INIS)

    To use solar irradiation or interior lighting efficiently, we sought a photocatalyst with high reactivity under visible light. Nitrogen and carbon doping TiO2-x-yN xC y films were obtained by heating the TiO2 gel in an ionized N2 gas and then were calcined at 500 deg. C. The TiO2-x-yN xC y films have revealed an improvement over the TiO2 films under visible light (wavelength, 500 nm) in optical absorption and photocatalytic activity such as photodegradation of methyl orange. X-ray photoemission spectroscopy, infrared spectrum and UV-visible (UV-vis) spectroscopy were used to find the difference of two kinds of films. Nitrogen and carbon doped into substitutional sites of TiO2 has been proven to be indispensable for band-gap narrowing and photocatalytic activity

  2. Photocatalytic activity of erbium-doped TiO2 nanoparticles immobilized in macro-porous silica films

    International Nuclear Information System (INIS)

    Highlights: ? Erbium-doped TiO2 nanoparticles were immobilized on macro-porous silica films. ? The films were obtained by a phase separation process. ? The samples exhibited photo-catalytic activity under visible light. ? The sensitization of TiO2 was attributed to a red shift in the TiO2 band-gap. -- Abstract: A macro-porous silica film served as mechanical support to immobilize TiO2 nanoparticles, which were doped with erbium. The films and the nanoparticles were prepared by sol–gel route. The nanoparticles exhibited photocatalytic activity under visible light. We obtained a degradation rate of methylene blue that followed first order kinetics. The sensitization of the nanoparticles to visible light was attributed to a red shift in the band-gap of the TiO2 due to the addition of erbium ions.

  3. TOF-SIMS study of photocatalytic decomposition reactions on nanocrystalline TiO2 films

    International Nuclear Information System (INIS)

    Nanocrystalline TiO2 is known to be a very efficient photocatalyst. In order to elucidate the details of reaction pathways occurring on the surface, nanocrystalline TiO2 films (with 12 nm average crystallite size) were covered by methylene blue (MB) and studied, both in the pristine state and upon UV exposure, by TOF-SIMS. Distinct mass signals related to the MB parent molecule (m = 284.1 amu) and from fragment ions are observed for the as-prepared samples. Upon irradiation with UV light under atmospheric conditions, the surface composition is pronouncedly changed, an observation ascribed to photocatalytic reactions induced by UV photons: the amount of the parent molecule is diminished whereas intermediate reaction products are identified to be present at the TiO2 surfaces. Eventually, the parent molecule and the characteristic fragment species disappear completely upon extended exposure to UV light

  4. Synthesis of TiO2/GO composite film via an electrochemical route.

    Science.gov (United States)

    He, Yunqiu; Wang, Ruihua; Zhang, Qiong; Chen, Xiaogang; Li, Linjiang; Hu, Donghu

    2010-11-01

    A nano-structured film composed of TiO2 and reduced graphite oxide (GO) was synthesized on ITO glass via a typical electrochemical route. A mixed solvent of Ti(SO4)2 and GO was prepared, with the addition of H2O2, HNO3 and DMF at different ratio. A setup of two electrodes of ITO glass in a plastic cell and an electrochemical analyzer is used for the film forming. The film is characterized with a microstructure of GO plates being perpendicular to the glass substrate, since GO in the electrolyte solvent is separated as small plates at about several nanometers in diameter. TiO2 is found being deposited between these GO plates. This microstructure is quite different from the film formed by normal deposition, where the GO plates are generally parallel to the substrate. The oxygen containing groups of C=O, C-O-C and C-OH on the GO surface are reduced because of neighboring to TiO2, it means two phases being bonded to each other at the interface. The photoelectric current of the composite film is compared with the pure TiO2 film, the former one is almost one time higher than the latter one. The degradation of methyl orange of two kinds of film is also analyzed under the irradiation of ultraviolet light. The photocatalytic activity of two kinds of film presents the same trend of variation as that of photoelectric current. These results suggest that the photoexcited electrons of TiO2 may quickly transfer to the glass substrate through the reduced GO neighbor, that owns a better conductivity, and so far decrease the recovery of excited electron-hole. The unordinary microstructure of the composite film may favor both to the electron transmission between the GO and ITO glass substrate, and to the light excitation of TiO2. The microstructure of different films was studies by AFM, XPS, FESEM. The photo-electrochemical property was measured by an electrochemical instrument Model CHI660C with Blupoint4 as a UV light source. PMID:21137873

  5. Preparation and Characterization of Fe-Doped TiO2 Thin Layers.

    Czech Academy of Sciences Publication Activity Database

    Dragounová, Pavlína; Morozová, Magdalena; Šolcová, Olga

    - : -, 2014, P.25. ISBN N. [Pannonian Symposium on Catalysis /12./. T?eš? (CZ), 16.09.2014-20.09.2014] R&D Projects: GA TA ?R TA01020804 Grant ostatní: NATO(US) SPS984398 Institutional support: RVO:67985858 Keywords : sol-gel technique * Fe-doped TiO2 * thin layers Subject RIV: CI - Industrial Chemistry, Chemical Engineering http://pannonia2014.icpf.cas.cz/wp-content/uploads/2014/09/abstrakty_final.pdf

  6. Highly flexible self-standing film electrode composed of mesoporous rutile TiO2/C nanofibers for lithium-ion batteries

    International Nuclear Information System (INIS)

    There is increasing interest in flexible, safe, high-power thin-film lithium-ion batteries which can be applied to various modern devices. Although TiO2 in rutile phase is highly attractive as an anode material of lithium-ion batteries for its high thermal stability and theoretical capacity of 336 mA h g?1 and low price, its inflexibility and sluggish lithium intercalation kinetics of bulk phase strongly limit its practical application for particular in thin-film electrode. Here we show a simple way to prepare highly flexible self-standing thin-film electrodes composed of mesoporous rutile TiO2/C nanofibers with low carbon content (2 in as-fabricated nanofibers. Big size (10 cm × 4 cm), flexible thin film is obtained after heat treatment under 10%H2–Ar at 900 °C for 3 h. After optimization, the diameter of fibers can reach as small as ?110 nm, and the as-prepared rutile TiO2 films show high initial electrochemical activity with the first discharge capacity as high as 388 mA h g?1. What is more, very stable reversible capacities of ?122, 92, and 70 mA h ties of ?122, 92, and 70 mA h g?1 are achieved respectively at 1, 5 and 10 C rates with negligible decay rate within 100 cycling times.

  7. Initial deposition and electron paramagnetic resonance defects characterization of TiO2 films prepared using successive ionic layer adsorption and reaction method

    International Nuclear Information System (INIS)

    Successive ionic layer adsorption and reaction (SILAR) technique was considered promisingly to deposit ultra thin titanium dioxide (TiO2) films under ambient condition. In this paper, the growth process, structures and paramagnetic defects of the films were characterized by complementary techniques of atomic force microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy and electron paramagnetic resonance spectroscopy. The results indicate that on glass substrate the SILAR TiO2 film nucleates in an island mode within the initial five deposition cycles but grows in a layer-by-layer mode afterwards. The growth rate was measured as 4.6 Å/cycle. In the as-deposited films, a kind of paramagnetic defects is detected at g (2.0029) and it can be attributed to oxygen vacancies. These as-received oxygen vacancies could be annealed out at 473 K. Ultraviolet irradiation on the as-deposited films can also decrease the density of the defects. The relative mechanisms on the phenomenon were discussed in this paper. - Highlights: ? TiO2 films are deposited on glass at 25 °C by successive ionic layer adsorption and reaction method with a rate of 4.6 Å/cycle. ? The films nucleate in an island mode initially but grow in a layer mode afterwards. ? The SILAR TiO2 films nucleation period is five cycles. ? Electron paramagnetic resonance spectroscopy shows that TiO2 films paramagnetic defects are attributed to oxygen vects are attributed to oxygen vacancies. ? They will decrease by anneal or ultraviolet radiation and form hydroxyl or superoxide radicals.

  8. Photocatalysts of Cr Doped TiO2 Film Prepared by Micro Arc Oxidation

    Science.gov (United States)

    Wan, Li; Li, Jian-feng; Feng, Jia-you; Sun, Wei; Mao, Zong-qiang

    2008-10-01

    A series of Cr doped TiO2 films were prepared by micro arc oxidation (MAO) using an electrolyte of Na3PO4+K2Cr2O7. X-ray diffraction and scanning electron microscopy revealed that the films mainly consisted of anatase phase with a porous surface morphology. The films have an excellent photocatalytic effect for degradation of methylene blue and decomposition of water under visible light illumination. This arises from the formation of Cr3+/Cr4+ and oxygen vacancy energy levels owing to Cr doping. The former reduces the electron-hole recombination chance, while the latter generates a new gap between the conduction band (CB) and valence band (VB) of TiO2, which lowers the photo energy of the excited electron in the VB to the oxygen vacancy states. The mechanisms for film synthesis during the MAO process are also presented.

  9. Synthesis of Bi2O3-TiO2 composite film with high-photocatalytic activity under sunlight irradiation

    International Nuclear Information System (INIS)

    Bi2O3-TiO2 composite films were synthesized by a sol-gel method under mild condition (i.e. low temperature and ambient pressure). The as-prepared films were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, infrared spectra and fluorescence spectra. The results showed that Bi2O3-TiO2 composite films were composed of anatase titania and Bi2O3. TiO2 particles were deposited on the surface of Bi2O3 to form uniform film. Incorporating Bi2O3 with TiO2 leads to increased surface OH group density. All Bi2O3-TiO2 composite films exhibited higher photocatalytic activity compared with pure TiO2 under solar irradiation, while the film with Bi/Ti atomic ratio of 1.25% showed the highest photocatalytic activity. Furthermore, the as-prepared films can be reused with little photocatalytic activity decreasing. Without any further treatment besides rinsing, the photocatalytic activity of Bi2O3-TiO2 (1.25%) films was still higher than 77% after six-cycle utilization.

  10. Liquid phase deposition of electrochromic thin films

    Energy Technology Data Exchange (ETDEWEB)

    Richardson, Thomas J.; Rubin, Michael D.

    2000-08-18

    Thin films of titanium, zirconium and nickel oxides were deposited on conductive SnO2:F glass substrates by immersion in aqueous solutions. The films are transparent, conformal, of uniform thickness and appearance, and adhere strongly to the substrates. On electrochemical cycling, TiO2, mixed TiO2-ZrO2, and NiOx films exhibited stable electrochromism with high coloration efficiencies. These nickel oxide films were particularly stable compared with films prepared by other non-vacuum techniques. The method is simple, inexpensive, energy efficient, and readily scalable to larger substrates.

  11. Dye assessment in nanostructured TiO2 sensitized films by microprobe techniques [Poster] 

    OpenAIRE

    Barreiros, Maria Alexandra; Mascarenhas, Joa?o; Corregidor, V.; Alves, L. C.; Guimara?es, Fernanda M. G.; Torres, Erica; Brites, Maria Joa?o

    2014-01-01

    Dye sensitized solar cells (DSCs) have received considerable attention once this technology offers economic and environmental advantages over conventional photovoltaic (PV) devices. The PV performance of a DSC relies on the characteristics of its photoanode, which typically consists of a nanocrystalline porous TiO2 film, enabled with a large adsorptive surface area. Dye molecules that capture photons from light during device operation are attached to the film nanoparticles. The effect...

  12. Preparation of cerium-doped TiO2 film on 304 stainless steel and its bactericidal effect in the presence of sulfate-reducing bacteria (SRB)

    International Nuclear Information System (INIS)

    Cerium-doped TiO2 film with bactericidal activity was prepared on 304 stainless steel by a sol-gel process. The doped cerium ions were identified to have retarding effect on the phase transition from amorphous TiO2 to anatase TiO2. This effect was interpreted as the distortion of crystal lattice, due to the introduction of cerium ions into the crystal structure of TiO2. The absorption band edge of cerium-doped TiO2 film has a red shift compared with that of pure TiO2 film in UV-vis spectra. The films covered with sulfate-reducing bacteria (SRB) medium were exposed to sunlight for 6 h and the bactericidal efficiency was evaluated with most probable number technique. It was found that the bactericidal efficiency of cerium-doped TiO2 film and pure TiO2 film were 95% and 85%, respectively.

  13. Nanometer-thin TiO2 enhances skeletal muscle cell phenotype and behavior

    Directory of Open Access Journals (Sweden)

    Ishizaki K

    2011-10-01

    Full Text Available Ken Ishizaki*, Yoshihiko Sugita*, Fuminori Iwasa, Hajime Minamikawa, Takeshi Ueno, Masahiro Yamada, Takeo Suzuki, Takahiro OgawaLaboratory for Bone and Implant Sciences, The Jane and Jerry Weintraub Center for Reconstructive Biotechnology, Division of Advanced Prosthodontics, Biomaterials and Hospital Dentistry, UCLA School of Dentistry, Los Angeles, CA, USA*Authors contributed equally to this workBackground: The independent role of the surface chemistry of titanium in determining its biological properties is yet to be determined. Although titanium implants are often in contact with muscle tissue, the interaction of muscle cells with titanium is largely unknown. This study tested the hypotheses that the surface chemistry of clinically established microroughened titanium surfaces could be controllably varied by coating with a minimally thin layer of TiO2 (ideally pico-to-nanometer in thickness without altering the existing topographical and roughness features, and that the change in superficial chemistry of titanium is effective in improving the biological properties of titanium.Methods and results: Acid-etched microroughened titanium surfaces were coated with TiO2 using slow-rate sputter deposition of molten TiO2 nanoparticles. A TiO2 coating of 300 pm to 6.3 nm increased the surface oxygen on the titanium substrates in a controllable manner, but did not alter the existing microscale architecture and roughness of the substrates. Cells derived from rat skeletal muscles showed increased attachment, spread, adhesion strength, proliferation, gene expression, and collagen production at the initial and early stage of culture on 6.3 nm thick TiO2-coated microroughened titanium surfaces compared with uncoated titanium surfaces.Conclusion: Using an exemplary slow-rate sputter deposition technique of molten TiO2 nanoparticles, this study demonstrated that titanium substrates, even with microscale roughness, can be sufficiently chemically modified to enhance their biological properties without altering the existing microscale morphology. The controllable and exclusive chemical modification technique presented in this study may open a new avenue for surface modifications of titanium-based biomaterials for better cell and tissue affinity and reaction.Keywords: nanotechnology, orthopedic implants, molten TiO2 nanoparticles, surface chemistry

  14. Electrophoretic deposition of TiO2 film on titanium foil for a flexible dye-sensitized solar cell

    International Nuclear Information System (INIS)

    Electrophoretic deposition (EPD) method is employed to obtain mesoporous TiO2 film on a titanium (Ti) foil; the film is then mechanically compressed and sintered at 350 deg. C before being subjected to dyeing. A comprehensive study was made on the mechanistic aspects of the EPD process. The dye-sensitized solar cell (DSSC) using the thus formed TiO2 film rendered a power conversion efficiency (Eff.) of 6.5%. Effects of various compression pressures on the photovoltaic parameters and on other characteristic parameters of the pertinent DSSCs are studied. Electrochemical impedance spectroscopy (EIS) is applied for the first time, using a novel equivalent model, to study the impedance behavior of the DSSC with this type of TiO2 film. We also obtain characteristic parameters of the TiO2 photoanode by using EIS. The coordination number of the TiO2 film, and the ratio of charge transfer resistances of electron recombination and electron transport are also obtained and analyzed. Moreover, we employ a multilayer approach and increase the film thickness to prepare TiO2 films with the same coordination number and porosity; DSSCs using such TiO2 films obtained from P90 and P25 rendered efficiencies of 6.5% and 5.24%, respectively. Scanning electron microscopy (SEM) micrographs are obtained to characterize the TiO2 films formed by the EPD technique and laser-induced transient technique is used laser-induced transient technique is used to estimate the electron lifetime in the TiO2 films.

  15. Controllable nitrogen doping in as deposited TiO2 film and its effect on post deposition annealing

    International Nuclear Information System (INIS)

    In order to narrow the band gap of TiO2, nitrogen doping by combining thermal atomic layer deposition (TALD) of TiO2 and plasma enhanced atomic layer deposition (PEALD) of TiN has been implemented. By altering the ratio between TALD TiO2 and PEALD TiN, the as synthesized TiOxNy films showed different band gaps (from 1.91?eV to 3.14?eV). In situ x-ray diffraction characterization showed that the crystallization behavior of these films changed after nitrogen doping. After annealing in helium, nitrogen doped TiO2 films crystallized into rutile phase while for the samples annealed in air a preferential growth of the anatase TiO2 along (001) orientation was observed. Photocatalytic tests of the degradation of stearic acid were done to evaluate the effect of N doping on the photocatalytic activity

  16. Nano-structure TiO2 film coating on 316L stainless steel via sol-gel technique for blood compatibility improvement

    Directory of Open Access Journals (Sweden)

    Mohammadreza Foruzanmehr

    2014-04-01

    Full Text Available   Objective(s: Titanium oxides are known to be appropriate hemocompatible materials which are suggested as coatings for blood-contacting devices. Little is known about the influence of nanometric crystal structure, layer thickness, and semiconducting characteristics of TiO2 on blood hemostasis.   Materials and Methods: Having used sol-gel dip coating method in this study, TiO2 thin films were deposited on nano-scale electro-polished stainless steel 316L with 1 to 5 nano-sized layers. Surface morphology and structure of the film were studied with X-ray diffraction and atomic force microscopy. Blood compatibility was also determined by measuring the platelet activation (CD62P expression, platelet adhesion (Scanning Electron Microscopy, and the blood clotting time on these samples. Results: The films were compact and smooth and existed mainly in the form of anatase. By increasing the number of TiO2 thin layer, clotting time greatly extended, and the population of activated platelet and P-selectine expression changed according to the surface characteristics of each layer. Conclusion: The findings revealed that stainless steel 316L coated with nano-structured TiO2 layer improved blood compatibility, in terms of both blood platelet activity and coagulation cascade, which can decrease the thrombogenicity of blood contacting devices which were made from stainless steel.

  17. Structural and optical investigations of TiO2 films deposited on transparent substrates by sol-gel technique

    International Nuclear Information System (INIS)

    An inexpensive and effective simple method for the preparation of nano-crystalline titanium oxide (anatase) thin films at room temperature on different transparent substrates is presented. This method is based on the use of peroxo-titanium complex, i.e. titanium isopropoxide as a single initiating organic precursor. Post-annealing treatment is necessary to convert the deposited amorphous film into titanium oxide (TiO2) crystalline (anatase) phase. These films have been characterized for X-ray diffraction (XRD) studies, atomic force microscopic (AFM) studies and optical measurements. The optical constants such as refractive index and extinction coefficient have been estimated by using envelope technique. Also, the energy gap values have been estimated using Tauc's formula for on glass and quartz substrates are found to be 3.35 eV and 3.39 eV, respectively

  18. Microwave Photocatalysis III. Transition Metal Ion-Doped TiO2 Thin Films on Mercury Electrodeless Discharge Lamps: Preparation, Characterization and Their Effect on the Photocatalytic Degradation of Mono-Chloroacetic Acid and Rhodamine B.

    Czech Academy of Sciences Publication Activity Database

    Žabová, Hana; Církva, Vladimír

    2009-01-01

    Ro?. 84, ?. 11 (2009), s. 1624-1630. ISSN 0268-2575 R&D Projects: GA ?R GA104/07/1212; GA ?R(CZ) GD203/08/H032 Institutional research plan: CEZ:AV0Z40720504 Keywords : microwave * photocatalysis * thin film Subject RIV: CH - Nuclear ; Quantum Chemistry Impact factor: 2.045, year: 2009

  19. Enhancement of the photocatalytic property of TiO2 columnar nanostructured films by changing deposition angle

    International Nuclear Information System (INIS)

    Highlights: • Isolated and inclined columnar TiO2 nanostructures were obtained by sputtering Ti, and subsequently annealing. • The film performed photocatalytic decolorization effectively under UV irradiation. • The photocatalytic efficiency increased with deposition angle, which results in a more porous micro structure of the films. - Abstract: Isolated and inclined columnar nanostructured TiO2 films were obtained by sputtering titanium with glancing angle deposition method and subsequently annealing in air. Compared with flat film, TiO2 film fabricated with this method has higher porosity; compared with TiO2 powder, it overcomes the obstacles of immobilization and recycling. The TiO2 photocatalysis was evaluated by the degradation of methyl orange under UV light. It was indicated that the photocatalytic performance increased with deposition angle, which changed the porosity of the films. The relationship between deposition angle (the angle between the target and substrate surface) and the TiO2 columnar inclination angle (the angle between TiO2 columnar and substrate normal) was discussed

  20. Hydrophilicity, photocatalytic activity and stability of tetraethyl orthosilicate modified TiO2 film on glazed ceramic surface

    Science.gov (United States)

    Zhang, Peng; Tian, Jie; Xu, Ruifen; Ma, Guojun

    2013-02-01

    A new, simple, and low-cost method has been developed to enhance the surface properties of TiO2 film. Degussa P25-TiO2 nanoparticles were modified by tetraethyl orthosilicate (TEOS) on glazed ceramic tiles. Effects of tetraethyl orthosilicate modification on microstructure, crystal structure, hydrophilicity, photocatalytic activity and stability of the film were investigated. The obtained results showed that P25-TiO2/TEOS particles exhibited better dispersion, higher surface area, bigger surface roughness and smaller particle size comparing to pure P25-TiO2 particles, which resulted in better hydrophilicity after 10 days in a dark place and higher photocatalytic activity under visible light irradiation. 68% of Rhodamine B was degraded by P25-TiO2/TEOS film in 25 h with the light intensity of 5000 ± 500 lx, and degradation rate reached to 82% with the light intensity of 10,000 ± 1000 lx. Furthermore, two fundamentally different systems, in which the films recycle for repetitive degradation after soaked in dye solution and for discoloration after depositing dye on the surfaces, respectively, were measured to confirm that P25-TiO2/TEOS film showed excellently stable performances. Therefore the P25-TiO2/TEOS film we obtained has good washing resistance and would be a promising candidate for practical applications.

  1. Effect of oxygen partial pressure on the ferromagnetism of Cr-doped TiO2 films

    International Nuclear Information System (INIS)

    Polycrystalline Cr-doped TiO2 films were fabricated by co-sputtering Cr and TiO2 targets in a pure Ar and O2 mixture with various oxygen partial pressures. Ferromagnetism is observed in all samples and the Curie temperatures are well above 390 K. The saturation magnetization of films shows strong dependence on the oxygen growth pressure while keeping a constant Cr concentration. The ferromagnetism is enhanced in the films deposited at lower oxygen pressures which are thus oxygen deficient, indicating an important role of oxygen vacancies in the ferromagnetic origin of Cr-doped TiO2

  2. Photocatalytic thin films: their characterisation and antimicrobial properties

    OpenAIRE

    Page, K.

    2009-01-01

    This thesis is concerned with the synthesis and characterisation of TiO2 based photocatalyst thin films and the assessment of their antimicrobial properties. When exposed to light of wavelength less than 380 nm TiO2 films can demonstrate self-cleaning and self-disinfecting properties. This is due to photocatalytic processes occurring on the film surface resulting in film superhydrophilicity and reactive oxygen species (ROS) production. These ROS and radicals readily oxidise organic pollutants...

  3. Improved metal-insulator-transition characteristics of ultrathin VO2 epitaxial films by optimized surface preparation of rutile TiO2 substrates

    International Nuclear Information System (INIS)

    Key to the growth of epitaxial, atomically thin films is the preparation of the substrates on which they are deposited. Here, we report the growth of atomically smooth, ultrathin films of VO2 (001), only ?2?nm thick, which exhibit pronounced metal-insulator transitions, with a change in resistivity of ?500 times, at a temperature that is close to that of films five times thicker. These films were prepared by pulsed laser deposition on single crystalline TiO2(001) substrates that were treated by dipping in acetone, HCl and HF in successive order, followed by an anneal at 700–750??°C in flowing oxygen. This pretreatment removes surface contaminants, TiO2 defects, and provides a terraced, atomically smooth surface

  4. The effect of dye density on the efficiency of photosensitization of TiO2 films: light-harvesting by phenothiazine-labelled dendritic ruthenium complexes.

    Science.gov (United States)

    Fox, Marye Anne; Whitesell, James K; Magde, Douglas; Zhu, Lin-Yong

    2009-01-01

    A family of dendritic tris-bipyridyl ruthenium coordination complexes incorporating two or four carboxylate groups for binding to a TiO(2) surface site and another dendritic linker between the metal complex and highly absorptive dyes were formulated as thin films on TiO(2) coated glass. The family included phenothiazine-substituted dendrons of increasing structural complexity and higher optical density. The dye-loaded films were characterized by steady-state emission and absorption measurements and by kinetic studies of luminescence and transient absorption. Upon photoexcitation of the bound dyes, rapid electron injection into the metal oxide film was the dominant observed process, producing oxidized dye that persisted for hundreds of milliseconds. Complex decay profiles for emission, transient absorption, and optical bleaching of the dendritic dyes point to highly heterogeneous behavior for the films, with observed persistence lifetimes related directly to structurally enhance electronic coupling between the metal oxide support and the dendritic dyes. PMID:19924034

  5. The Effect of Dye Density on the Efficiency of Photosensitization of TiO2 Films: Light-Harvesting by Phenothiazine-Labelled Dendritic Ruthenium Complexes

    Directory of Open Access Journals (Sweden)

    Lin-Yong Zhu

    2009-09-01

    Full Text Available A family of dendritic tris-bipyridyl ruthenium coordination complexes incorporating two or four carboxylate groups for binding to a TiO2 surface site and another dendritic linker between the metal complex and highly absorptive dyes were formulated as thin films on TiO2 coated glass. The family included phenothiazine-substituted dendrons of increasing structural complexity and higher optical density. The dye-loaded films were characterized by steady-state emission and absorption measurements and by kinetic studies of luminescence and transient absorption. Upon photoexcitation of the bound dyes, rapid electron injection into the metal oxide film was the dominant observed process, producing oxidized dye that persisted for hundreds of milliseconds. Complex decay profiles for emission, transient absorption, and optical bleaching of the dendritic dyes point to highly heterogeneous behavior for the films, with observed persistence lifetimes related directly to structurally enhance electronic coupling between the metal oxide support and the dendritic dyes.

  6. Synthesis of capped TiO2 nanocrystals of controlled shape and their use with MEH-PPV conjugated polymer to develop nanocomposite films for photovoltaic applications

    Science.gov (United States)

    Mighri, F.; Duong, Vu Thi Thuy; On, Do Trong; Ajji, A.

    2014-05-01

    This study presents the synthesis details of titanium dioxide (TiO2) nanoparticles (NPs) of different shapes (nanospheres, nanorods and nanorhombics) using oleic acid (OA) and oleyl amine (OM) as capping agents. In order to develop nanocomposite thin films for photovoltaic cells, these TiO2 NPs were carefully dispersed in 2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene vinylene (MEH-PPV) matrix. The properties of synthesized TiO2 NPs and MEH-PPV/TiO2 nanocomposites were characterized using transmission electron microscopy (TEM), thermogravimetric analysis (TGA), UV-Visible spectroscopy, and Photoluminescence technique. It was found that the shape of NPs and the amount of OA and OM surfactants capped on their surface have an effect on their energy bandgap and also on the dispersion quality of MEH-PPV/TiO2 nanocomposites. Even though there was no evidence of chemical bonding between MEH-PPV matrix and TiO2 dispersed NPs, MEH-PPV/TiO2 nanocomposites showed very promising results for light absorption properties and charge transfer at the interface of the conjugated MEH-PPV matrix and TiO2 dispersed NPs, which are two main characteristics for photovoltaic materials.

  7. Thin carbon layer coated Ti(3+)-TiO2 nanocrystallites for visible-light driven photocatalysis.

    Science.gov (United States)

    Jiang, Baojiang; Tang, Yunqi; Qu, Yang; Wang, Jian-Qiang; Xie, Ying; Tian, Chungui; Zhou, Wei; Fu, Honggang

    2015-03-21

    Black TiO2 containing Ti(3+) attracts enormous attention due to its excellent visible-light driven photocatalytic activity. Herein, an in situ thermal decomposition approach to synthesize uniform thin carbon coated Ti(3+)-TiO2 nanocrystals is presented. During the oleic acid-assisted solvothermal process, the crystal size and morphology of TiO2 were controlled through oleic acid with carboxylic acid groups. Then the residual small quantities of oleic acid anchored on TiO2 were used as a carbon source, which could be in situ pyrolyzed into a carbon layer on TiO2 at high temperature and under an inert atmosphere. Meanwhile, Ti(4+) species were partly reduced into Ti(3+) states/oxygen vacancies on the surface of TiO2 due to the carbothermal reduction reaction for the carbon-encapsulated Ti(3+)-TiO2 structure. A series of characterizations indicated that the 20-25 nm TiO2 nanocrystals obtained were wrapped evenly by 1-2 nm carbon layers, which had an important effect on the energy band structure change of TiO2. The presence of the carbon layer also improves the Ti(3+) stability and the conduction behavior of the composites. The Ti(3+) states/oxygen vacancies created on the surface of TiO2 were responsible for the remarkable photogenerated charge separation and extended visible-light absorption range. Furthermore, Ti(3+) states/oxygen vacancies and the carbon layer together could enhance the adsorption ability of O2 so as to promote the photogenerated electrons captured by the adsorbed O2, leading to a great increase in the charge separation. As a result, the composites exhibit high photocatalytic performance for organic pollutants under visible light irradiation. This simple and new method may pave the way to practical applications for efficient photocatalytic degradation under visible light. PMID:25697803

  8. Novel Synthesis of the TiO2(B) Multilayer Templated Films.

    Czech Academy of Sciences Publication Activity Database

    Procházka, Jan; Kavan, Ladislav; Zukalová, Markéta; Frank, Otakar; Kalbá?, Martin; Zukal, Arnošt; Klementová, Mariana; Carbone, D.; Graetzel, M.

    2009-01-01

    Ro?. 21, ?. 8 (2009), s. 1457-1464. ISSN 0897-4756 R&D Projects: GA MŠk LC510; GA AV ?R IAA400400804; GA AV ?R KAN200100801; GA AV ?R KAN100500652 Institutional research plan: CEZ:AV0Z40400503; CEZ:AV0Z40320502 Keywords : TiO2 (B) * synthesis * films Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 5.368, year: 2009

  9. Facile method for synthesis of TiO2 film and its application in high efficiency dye sensitized-solar cell (DSSC)

    International Nuclear Information System (INIS)

    Dye-sensitized solar cells (DSSC) is a device which converts a solar energy to electrical energy. Different with semiconductor thin film based solar cell, DSSC utilize the sensitized-dye to absorb the photon and semiconductor such as titanium dioxide (TiO2) and zinc oxide (ZnO) as a working electrode photoanode. In this report, the preparation of TiO2 film using a facile method of spray deposition and its application in DSSC have been presented. TiO2 photoanode was synthesized by growing the droplet of titanium tetraisopropoxide diluted in acid solution on the substrate of conductive glass flourine-doped tin oxide (FTO) with variation of precursor volume. DSSC was assemblied by sandwiching both of photoanode electrode and platinum counter electrode subsequently filling the area between these electrodes with triodine/iodine electrolite solution as redox pairs. The characterization of the as prepared DSSC using solar simulator (AM 1.5G, 100 mW/cm2) and I-V source meter Keithley 2400 showed that the performance of DSSC was affected by the precursor volume.. The overall conversion efficiency of DSSC using the optimum TiO2 film was about 1.97% with the open circuit voltage (Voc) of 0.73 V, short circuit current density (Jsc) of 4.61 mA and fill factor (FF) of 0.58

  10. Low-temperature liquid phase deposited TiO2 films on stainless steel for photogenerated cathodic protection applications

    International Nuclear Information System (INIS)

    The low-temperature synthesis of anatase TiO2 films was an imperative requirement for their application to corrosion prevention of metals. In this paper, a liquid phase deposition (LPD) technique was developed to prepare TiO2 films on SUS304 stainless steel (304SS) at a relatively low temperature (80 deg. C). The as-prepared films were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy and X-ray photon spectroscopy (XPS). It was observed that a dense and crack-free anatase TiO2 film with a thickness about 300 nm was obtained. The film contained some fluorine and nitrogen elements, and the amounts of these impurities were greatly decreased upon calcination. Under the white light illumination, the electrode potential of TiO2 coated 304SS rapidly shifted to a more negative direction. Moreover, the photopotential of TiO2/304SS electrode showed more negative values with increased film thickness. In conclusion, the photogenerated cathodic protection of 304SS was achieved by the low-temperature LPD-derived TiO2 film.

  11. Why is anatase a better photocatalyst than rutile? - Model studies on epitaxial TiO2 films

    OpenAIRE

    Tim Luttrell; Sandamali Halpegamage; Junguang Tao; Alan Kramer; Eli Sutter; Matthias Batzill

    2014-01-01

    The prototypical photocatalyst TiO2 exists in different polymorphs, the most common forms are the anatase- and rutile-crystal structures. Generally, anatase is more active than rutile, but no consensus exists to explain this difference. Here we demonstrate that it is the bulk transport of excitons to the surface that contributes to the difference. Utilizing high –quality epitaxial TiO2 films of the two polymorphs we evaluate the photocatalytic activity as a function of TiO2-film thickness. ...

  12. Memory programming of TiO2-x films by Conductive Atomic Force Microscopy evidencing filamentary resistive switching

    Science.gov (United States)

    Bousoulas, P.; Giannopoulos, J.; Giannakopoulos, K.; Dimitrakis, P.; Tsoukalas, D.

    2015-03-01

    Resistive Random Access Memory (RRAM) with a structure Au/Ti/TiO2-x/Au demonstrated a clear bipolar resistive switching behavior without the necessity of an initial electroforming process. The titanium oxide (TiO2-x) thin film was deposited by reactive RF magnetron sputtering at room temperature in a controlled oxygen/argon ambient. The high density of oxygen vacancies within the film (induced by the low oxygen content) is an essential component for the formation of conducting filaments and demonstration of DC or nanosecond pulsed resistance switching, but also impose limitations for the conduction behavior of the high resistance state. Conductive Atomic Force Microscopy (C-AFM) was then employed in order to investigate the nanoscale electrical properties of our device. In situ current distribution during the SET process disclosed possible formation of conducting filaments while DC sweeping bias voltage revealed an OFF/ON switching ratio of about 200. We have also demonstrated that by using C-AFM both a low resistance state and a high resistance state can be written by bipolar voltage application imaged by corresponding patterns on the TiO2-x current image, suggesting that oxygen ions movement at the Pt-Ir coated tip/TiO2-x interface plays a critical role in the resistive switching phenomenon and thus correlating the macroscopic characteristics of our device with its microscopic origins. Nanoscale resistance switching is also demonstrated by programming distinct patterns on the device's current image.

  13. Magnetic properties of thin CrO2 layers supported on polycrystalline TiO2

    OpenAIRE

    Brand, E.; Kellett, D.; Enever, Md; Fellows, Jt; Egdell, Rg

    2005-01-01

    Thin layers of CrO2 have been prepared on polycrystalline rutile TiO2 supports by thermal decomposition of wet-impregnated Cr(NO 3)3 in flowing oxygen under ambient pressure conditions. The nanocomposite material has been characterised by a range of techniques including X-ray powder diffraction and X-ray photoelectron spectroscopy; and magnetic properties have been investigated by SQUID magnetometry. The loading of the nitrate on the support is shown to provide a simple way of controlling the...

  14. Effect of surface fluorination on the photocatalytic and photo-induced hydrophilic properties of porous TiO2 films

    International Nuclear Information System (INIS)

    Porous surface-fluorinated TiO2 (F-TiO2) films were prepared through PEG modified sol-gel method and surface fluorination. The as-prepared films were characterized with XRD, FTIR, AFM, XPS and UV-vis DRS. The effects of surface fluorination on the photocatalytic activity and hydrophilicity of porous TiO2 film were studied by photocatalytic degradation of rhodamine B (RhB) as well as water contact angle (CA) on porous TiO2 film. The results showed that the surface fluorination increased the adsorption of RhB on the porous TiO2 film and enhanced the photocatalytic degradation of RhB. The concentration and pH of NaF solutions affected much the photocatalytic activity of porous TiO2 film. Porous F-TiO2 film prepared in 40 mM NaF solution at pH 4.0 showed the highest photocatalytic activity. Because of its porous structure, the porous F-TiO2 film had original water CA of 22.7 deg., which is much smaller than that of normal F-TiO2 film. Under UV light irradiation, the water CA of porous F-TiO2 film decreased to 5.1 deg. in 90 min.

  15. Effects of electron beam irradiation on the photoelectrochemical properties of TiO2 film for DSSCs

    International Nuclear Information System (INIS)

    ABSTRACT: TiO2 has been widely utilized for various industrial applications such as photochemical cells, photocatalysts, and electrochromic devices. The crystallinity and morphology of TiO2 films play a significant role in determining the overall efficiency of dye-sensitized solar cells (DSSCs). In this study, the preparation of nanostructured TiO2 films by electron beam irradiation and their characterization were investigated for the application of DSSCs. TiO2 films were exposed to 20–100 kGy of electron beam irradiation using 1.14 MeV energy acceleration with a 7.46 mA beam current and 10 kGy/pass dose rates. These samples were characterized using X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), and X-ray photoelectron spectroscopy (XPS) analysis. After irradiation, each TiO2 film was tested as a DSSC. At low doses of electron beam irradiation (20 kGy), the energy conversion efficiency of the film was approximately 4.0% under illumination of simulated sunlight with AM 1.5 G (100 mW/cm2). We found that electron beam irradiation resulted in surface modification of the TiO2 films, which could explain the observed increase in the conversion efficiency in irradiated versus non-irradiated films. - Highlights: ? The surface of TiO2 particles was modified by electron beam irradiation. ? The aggregation between each TiO2 particle was observediO2 particle was observed in the SEM images. ? Ti3+ state was enhanced due to the excess electron injection via electron beam irradiation. ? The power conversion efficiency of DSSCs was enhanced.

  16. Effect of substrate on surface morphology and photocatalysis of large-scale TiO2 films

    Science.gov (United States)

    Lopez, Lorena; Daoud, Walid A.; Dutta, Dushmanta; Panther, Barbara C.; Turney, Terence W.

    2013-01-01

    Nanostructured TiO2 films were prepared on a variety of substrates, including acid frosted soda-lime glass, acid frosted soda-lime glass pre-coated with a SiO2 barrier layer, commercial glazed ceramic tile and 6061 aluminum alloy. For each substrate, the phase and microstructure of the films were determined to be exclusively anatase. However, the growth of the TiO2 crystallites, the film morphology and thickness varied substantially with substrate. Thermal stress, resulting from the difference in the coefficient of thermal expansion between the substrates and the films, contributed to the formation and propagation of cracks. This was most clearly observed on the films deposited on SiO2 barrier layer and aluminum. The photocatalytic activity of the TiO2 films deposited on glass with and without SiO2 barrier layer, ceramic, and aluminum was studied via UV decolorization of methyl orange in aqueous solution. Complete degradation rapidly occurred on the TiO2/glass and TiO2/SiO2 barrier layer films, but not with the ceramic or metal substrates. It appears that the photocatalytic activity of the films deposited on aluminum and ceramic substrates was affected by the quantity and the size of the anatase crystallites. The aluminum substrate promoted the formation of TiO2 films with the largest anatase crystallite size, exhibiting a cracked morphology, where as the ceramic substrate resulted in the formation of TiO2 films with large crystallite size in an island morphology.

  17. Tensile properties of latex paint films with TiO2 pigment

    Science.gov (United States)

    Hagan, Eric W. S.; Charalambides, Maria N.; Young, Christina T.; Learner, Thomas J. S.; Hackney, Stephen

    2009-05-01

    The tensile properties of latex paint films containing TiO2 pigment were studied with respect to temperature, strain-rate and moisture content. The purpose of performing these experiments was to assist museums in defining safe conditions for modern paintings held in collections. The glass transition temperature of latex paint binders is in close proximity to ambient temperature, resulting in high strain-rate dependence in typical exposure environments. Time dependence of modulus and failure strain is discussed in the context of time-temperature superposition, which was used to extend the experimental time scale. Nonlinear viscoelastic material models are also presented, which incorporate a Prony series with the Ogden or Neo-Hookean hyperelastic function for different TiO2 concentrations.

  18. Visible-light photocatalysis in nitrogen-carbon-doped TiO2 films obtained by heating TiO2 gel-film in an ionized N2 gas

    International Nuclear Information System (INIS)

    To use solar irradiation or interior lighting efficiently, we sought a photocatalyst with high reactivity under visible light. Nitrogen and carbon doping TiO2 films were obtained by heating a TiO2 gel in an ionized N2 gas. The as-synthesized TiO2-x-yNxCy films have shown an improvement over titanium dioxide in optical absorption and photocatalytic activity such as photodegradation of methyl orange under visible light. The process of the oxygen atom substituted by nitrogen and carbon was discussed. Oxygen vacancy induced by the formation of Ti3+ species and nitrogen and carbon doped into substitution sites of TiO2 have been proven to be indispensable for the enhance of photocatalytic activity, as assessed by UV-Vis Spectroscopy and X-ray photoemission spectroscopy

  19. Co3O4/TiO2 films obtained by laser ablation and sol-gel for the reaction of oxygen liberation in alkaline medium

    International Nuclear Information System (INIS)

    The laser ablation technique known as Pulsed Laser Deposition (PLD) is used for obtaining thin films of TiO2/SnO2, which was later modified with Co3O4 by PLD or by sol-gel technique. The films were characterized by X-ray diffraction, ultraviolet Vis and Raman spectroscopies, scanning electron microscopy and energy analysis of the dispersed X-rays produced by Auger decay. The anatase phase with particles of nano metric size was obtained by depositing the titanium dioxide in argon atmosphere. The Co3O4 films obtained by PLD on the TiO2 showed the same morphology. The electrocatalytic activity of the films that were used as photo anodes for the reaction of oxygen liberation was carried out in the darkness, with environment light and the light emitted by a xenon lamp. The current density was higher for films of Co3O4/TiO2/SnO2 obtained by PLD that for cobalt dioxide of mixed valence obtained by sol-gel. (Author)

  20. Influence of the Substrate Temperature on the Properties of Nb―doped TiO2 Films Deposited by DC Magnetron Sputtering

    Directory of Open Access Journals (Sweden)

    HUANG Shuai, LI Chen-Hui, SUN Yi-Hua, KE Wen-Ming

    2012-01-01

    Full Text Available Nb―doped (2.5wt%) TiO2 thin films was deposited on glass substrate by DC magnetron sputtering from a ceramic target and the films thickness was controlled in the range from 300 nm to 350 nm. The structure, surface morphology and optical properties of the films deposited at different substrate temperatures were investigated by X―ray diffraction, scanning electron microscope, and optical transmission spectroscope. The films deposited at 150¡?250¡?nd 350¡?ere amorphous, anatase and rutile, respectively. The grain size of the typical anatase film deposited at 250¡?eached the maximum of 32 nm. The roughness of the films decreased and their density increased with the rising of substrate temperature. The average optical transmittance of films were around 70% when the substrate temperatures were below 250¡?As the substrate temperature were risen to 350¡?the films’ transmittance dropped to 59%. It indicated that the transmittance of visible light was hindered by the rutile phase in the Nd―doped TiO2 films. The optical band gap of the films were in the range from 3.68 eV to 3.78 eV, and the optical band gap of the typical anatase film deposited at 250¡?eached the highest value of 3.78 eV.

  1. A comparative study into the photocatalytic properties of thin mesoporous layers of TiO2 with controlled mesoporosity.

    Czech Academy of Sciences Publication Activity Database

    Tschirch, J.; Bahnemann, D.; Wark, M.; Rathouský, Ji?í

    2008-01-01

    Ro?. 194, 2-3 (2008), s. 181-188. ISSN 1010-6030 R&D Projects: GA MŠk 1M0577 Institutional research plan: CEZ:AV0Z40400503 Keywords : mesoporous films * film thickness * TiO2 * dye adsorption * photocatalytic degradation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.362, year: 2008

  2. Influence of laser modification of TiO2 films for its photocatalytic properties

    Science.gov (United States)

    Sawczak, Miros?aw; Górski, Micha?; Rachubi?ski, Hubert; Cenian, Adam

    2013-01-01

    The photocatalytic activity of TiO2 layer modified by laser radiation is discussed in the paper. Commercially available nanopowder P25(Degussa) was used, which consists of a mixture of anatase and rutile - two crystallographic forms of TiO2 . The spin-coating technique was applied to produce thin layers on glass. After drying and calcination the layer was thermally modified using a pulsed (6 ns) Nd:YAG laser (FHG 266 nm). This caused a clearly visible surface darkening effect. The XRD spectra show that phase change transition (from anatase to rutile) took place partially. This was also confirmed by Raman spectra. The main peak of Raman-spectra shifts from 142,84 to 145,22 cm-1, probably due to decreasing size of TiO2 nanoparticles or more probably due to a defects generation in nanocrystallite structure. Defects have been reported in the literature as surface oxygen depletion and generation valance states Ti3+ and Ti4+. Eventually, kinetics of methylene-blue decay and CO2 to methane conversion were examined. In both cases an increase of catalytic activity was observed.

  3. Solvent Effect on the Electrical and Optical Properties of Nano composite MEH-PPV: TiO2 Films for Organic Solar Cells Applications

    International Nuclear Information System (INIS)

    The influence of organic solvent on the electrical and optical properties of photodiodes based on poly[2-methoxy,5-(2'- ethylhexyloxy)-1,4-phenylene vinylene) MEHPPV) and nano-TiO2 nano composite are investigated. The films were prepared from TiO2 dispersed in MEH-PPV solutions in toluene, tetrahydrofuran (THF), xylene, chloroform and 1,3-dichlorobenzene (1,3- DCB) solvents at concentration of 20 mg/ 20 ml. The electrical properties of the MEH-PPV: TiO2 nano composite thin films were measured by solar simulator in dark and under illumination condition while the characterization of optical properties has using UV-VIS spectrophotometer to evaluate the absorbance. The solvent of 1,3-DCB shows a greater conductivity with 33.82x104 S.m-1 without photo response under illumination. (author)

  4. Preparation and characterization of amine-functionalized SiO2/TiO2 films for formaldehyde degradation

    International Nuclear Information System (INIS)

    This paper investigated the gaseous formaldehyde degradation by the amine-functionalized SiO2/TiO2 photocatalytic films for improving indoor air quality. The films were synthesized via the co-condensation reaction of methyltrimethoxysilane (MTMOS) and 3-aminopropyltrimethoxysilane (APTMS). The physicochemical properties of prepared photocatalysts were characterized with N2 adsorption/desorption isotherms measurement, X-ray diffraction (XRD) and Fourier Transform Infrared spectroscopy (FT/IR). The effect of amine-functional groups and the ratio of MTMOS/APTMS precursors on the formaldehyde adsorption and photocatalytic degradation were investigated. The results showed that the formaldehyde adsorption and photocatalytic degradation of the APTMS-functionalized SiO2/TiO2 film was higher than that of SiO2/TiO2 film due to the surface adsorption on amine sites and the relatively high of the specific surface area of the APTMS-functionalized SiO2/TiO2 film (?15 times higher than SiO2/TiO2). The enhancement of the formaldehyde degradation of the film can be attributed to the synergetic effect of adsorption and subsequent photocatalytic decomposition. The repeatability of photocatalytic film was also tested and the degradation efficiency was 91.0% of initial efficiency after seven cycles.

  5. TiO2/SiO2 Composite Films Immobilized on Foam Nickel Substrate for the Photocatalytic Degradation of Gaseous Acetaldehyde

    OpenAIRE

    Wenfeng Shangguan; Jianwei Shi; Jian Yuan; Wenjun Xiao; Hai Hu

    2008-01-01

    The photocatalyst anatase titanium dioxide (TiO2) films were immobilized via sol-gel technique on foam nickel modified with SiO2 films as transition layer (indicated as TiO2/SiO2 films). The structural properties of TiO2/SiO2 composite films were characterized using TG-DSC, XRD, FE-SEM, and BET. The photocatalytic activities of immobilized TiO2/SiO2 films were tested through photocatalytic degradation reactions of gaseous acetaldehyde under ultraviolet (UV) light irradiation. The substrate mo...

  6. Existence, release, and antibacterial actions of silver nanoparticles on Ag–PIII TiO2 films with different nanotopographies

    OpenAIRE

    Li, Jinhua; Qiao, Yuqin; Zhu, Hongqin; Meng, Fanhao; Liu, Xuanyong

    2014-01-01

    Nanotopographical TiO2 films (including nanorod, nanotip, and nanowire topographies) were successfully fabricated on the metallic Ti surface via hydrothermal treatment and then underwent Ag plasma immersion ion implantation to incorporate Ag with TiO2. The surface morphology, phase component, and chemical composition before and after Ag–PIII were characterized. In view of the potential clinical applications, both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus were us...

  7. Superhydrophilic porous TiO2 film prepared by phase separation through two stabilizers

    International Nuclear Information System (INIS)

    A novel method was developed to produce a TiO2 film with circular pores on its surface. The pores aroused from the precursor solution using both acetylacetone (AcAc) and diethanolamine (DEA) as stabilizers. The appearance of interconnected or isolated pores for the films was discussed in relation to the phase separation in the sol-gel process with the presence of Acac and DEA. Macropore size, together with connectivity of pores and gel skeleton, can be controlled by selecting an appropriate composition for preparation at DEA amount or regulating a time scale of the sol-gel transition. Finally, wetting behavior of the resulting films was characterized by using contact angle measurements. The TiO2 films with interconnected or relatively isolated pores exhibit superhydrophilic characteristic, although it is not exposed to ultraviolet irradiation. Deducing from the Wenzel-Cassie regimes' transition criterion, the existence of Cassie impregnating wetting regime rather than Wenzel one upon these porosity-driven superhydrophilic surfaces can be obtained.

  8. Low temperature (150 °C) fabrication of high-performance TiO2 films for dye-sensitized solar cells using ultraviolet light and plasma treatments of TiO2 paste containing organic binder

    Science.gov (United States)

    Zen, Shungo; Inoue, Yuki; Ono, Ryo

    2015-03-01

    Dye-sensitized solar cells (DSSCs) require annealing of TiO2 photoelectrodes at 450 °C to 550 °C. However, such high-temperature annealing is unfavorable because it limits the use of materials that cannot withstand high temperatures, such as plastic substrates. In our previous paper, a low-temperature annealing technique of TiO2 photoelectrodes using ultraviolet light and dielectric barrier discharge treatments was proposed to reduce the annealing temperature from 450 °C to 150 °C for a TiO2 paste containing an organic binder. Here, we measure the electron diffusion length in the TiO2 film, the amount of dye adsorption on the TiO2 film, and the sheet resistance of a glass substrate of samples manufactured with the 150 °C annealing method, and we discuss the effect that the 150 °C annealing method has on those properties of DSSCs.

  9. Photocatalytic reactor using titanium dioxide thin film on quartz tubes

    Science.gov (United States)

    Kouda, Ram Mahipal

    Photocatalysis process, as an environmental application is an advanced oxidation process with tremendous potential in the near future. Previously many researchers, have conducted photocatalysis in different reactor configuration using TiO2 slurry and thin film, using a UV light source, the constraints for these reactors are the need for the removal of TiO2 particles at the outlet stream in a slurry reactor and poor environment for the efficient use of TiO2 film using UV light, as the UV light penetration depth in water is about an inch. Taking all this into consideration, we propose a design for reactor with efficient contact of the aqueous phase to the TiO2 film so that UV light doesn't need to penetrate through water, the TiO2 particles need not be removed from the outlet stream of water. The wok involves the deposition of TiO2 on quartz tubes with TiO2 and TiO2-Fe doped film by sol-gel and ESA (electrostatic self assembly) method and testing the performance of the coated film in proposed photocatalytic reactor in degradation of congo red, KI and Nitro phenol.

  10. Mesoporous inverse opal TiO2 film as light scattering layer for dye-sensitized solar cell.

    Science.gov (United States)

    Jin, Mingshi; Kim, Sung Soo; Yoon, Minyoung; Li, Zhenghua; Lee, Yoon Yun; Kim, Ji Man

    2012-01-01

    The light harvesting efficiency of dye-sensitized solar cells was enhanced by using a scattering layer. Such as sphere type TiO2, inverse photonic crystal TiO2, hollow spherical TiO2. Among these materials, the TiO2 with inverse photonic crystal (IPC) structure, synthesized by self-assembly using spherical templates, has attracted much attention due to their photonic crystal characteristics and light scattering effects. However, when applied in the DSSCs, the surface area of IPC is very low that caused insufficient adsorption amount of dye molecules. In the present work, a scattering layer with mesoporous inverse photonic crystal (MIPC) TiO2 film was fabricated by the sol-gel reactions with surfactant-assisted sol-gel method using poly(methyl methacrylate) as the template and titanium (IV) isopropoxide as the TiO2 precursor. After removing the PMMA and surfactant, a highly ordered macroporous structure with mesopores were successfully obtained. The surface area and total pore volume of the MIPC were 82 m2/g and 0.31 cm3/g, respectively, which is much larger than those of the IPC. The DSSCs with the scattering layer of MIPC film exhibited 18 and 10% higher photo-conversion efficiency than those of cells only with a nano-crystalline TiO2 film and with scattering layer of IPC film. From UV-visible spectra of dye solutions, the MIPC film showed a higher amount of absorbed dye molecules than those of the reference and IPC films. Accordingly, an increase in the photo-current density through abundant adsorption of the dye, coupled with inherent light scattering ability can improve overall photo-conversion efficiency. PMID:22524063

  11. One-step Fabrication of Crack-free, Hierarchically-ordered TiO2 Films via Self-assembly of Polystyrene Bead and Preformed TiO2

    International Nuclear Information System (INIS)

    Graphical abstract: One-step self-assembly of polystyrene bead and preformed TiO2 results in crack-free ordered TiO2 films with higher thickness and a meso/macroscopic scale hierarchical structure. The hierarchically-ordered TiO2-based solid-state dye-sensitized solar cell exhibited higher efficiency than a less-organized, nanoparticle-based cell using commercially available paste, indicating more effectiveness in solid-state high molecular weight systems. - Abstract: Crack-free, hierarchically-ordered TiO2 films were prepared via one-step co-assembly of a 400-nm polystyrene bead and hydrophilically preformed TiO2. Large volume loss of titanium(IV) bis(ammonium lactato) dihydroxide, a commonly used precursor, led to substantial crack formation of the film. However, the use of preformed TiO2 resulted in less cracked films with higher thickness and a meso/macroscopic scale hierarchical structure. This is because the preformed TiO2 particles electrostatically assembled onto the polystyrene bead surface, as confirmed by scanning electron microscope and a zeta potential analyzer. When these structures were implemented as photoanodes in quasi-solid-state dye-sensitized solar cells using a nanogel electrolyte, the efficiency of the preformed TiO2-based cell was 1.8-fold greater than that of a titanium(IV) bis(ammonium lactato) dihydroxide-based cell, indicating the importance of the precursor. Upon fabrication of solid-state dye-sensitized solar cells using a high molecular weight polymer and the TiCl4-treated TiO2 film, the efficiency was much greater than that of less-organized, nanoparticle-based cells fabricated with commercially available paste (Dyesol, 18NR-T). This indicates the increased effectiveness of the film in solid-state high molecular weight systems

  12. Room-temperature ferromagnetism in (Mn, N)-codoped TiO2 films grown by plasma assisted molecular beam epitaxy

    Science.gov (United States)

    Li, X. Y.; Wu, S. X.; Xu, L. M.; Liu, Y. J.; Xing, X. J.; Li, S. W.

    2008-11-01

    (Mn, N)-codoped TiO2 films have been fabricated by plasma assisted molecular beam epitaxy. X-ray diffraction and x-ray photoelectron spectroscopy studies indicate the incorporation of both Mn and N ions into the TiO2 lattice but without Mn metal clusters. Ferromagnetism with clear hysteresis at 300 K is observed in (Mn, N)-codoped TiO2 films, whereas the films without nitrogen show paramagnetic behavior. It is demonstrated experimentally that the intentional nitrogen doping plays an important role in realizing dominant ferromagnetic ordering in Mn-doped TiO2 films.

  13. High-Quality Fe-doped TiO2 films with Superior Visible-Light Performance

    DEFF Research Database (Denmark)

    Su, Ren; Bechstein, Ralf

    2012-01-01

    We report on high-quality polycrystalline Fe-doped TiO2 (Fe–TiO2) porous films synthesized via one-step electrochemical oxidation. We demonstrate that delicate properties such as the impurity concentration and the microstructure that strongly influence the performance of the material for photovoltaic and photocatalysis applications can be controlled by adjusting the electrolyte composition. Compared to Fe-doped TiO2 films prepared with traditional phosphate- or silicate-based electrolytes, our newly synthesised Fe–TiO2 films contain solely Fe dopants, which results in excellent photocatalytic and photovoltaic performance under visible light irradiation.

  14. Intrinsic defects and their influence on the chemical and optical properties of TiO2x films

    OpenAIRE

    Laidani, N.; Cheyssac, P.; Perrie?re, J.; Bartali, R.; Gottardi, G.; Luciu, I.; Micheli, V.

    2010-01-01

    ABSTRACT In this work, TiO 2 films produced by rf sputtering of a TiO 2 target, in argon and argon-oxygen plasmas were studied. The oxygen content in the feed gas was varied in a range of 3% – 20%. The chemical composition and structure of films were characterized by Rutherford backscattering spectrometry (RBS), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction. Important information about the intrinsic defects of the films and their effects on the optical properties as well a...

  15. Dip-coated TiO2CeO2 films as transparent counter-electrode for transmissive electrochromic devices

    OpenAIRE

    Baudry, Paul; Rodrigues, A.C.M.; Aegerter, Michel A.; Bulhoes, Luis O. S.

    1990-01-01

    The dip-coating process is an attractive way for the preparation of thin films used in the field of electrochromism. The scope of the present paper is focused on the TiO2CeO2 compounds since they exhibit a reversible electrochemical insertion of lithium ions maintaining a high optical transmissivity. These films can be used as transparent counter-electrode in an all solid state electrochromic transmissive device with, for example, WO3 as electrochromic material and a lithium conductive po...

  16. Visible-light-driven photogenerated cathodic protection of stainless steel by liquid-phase-deposited TiO2 films

    International Nuclear Information System (INIS)

    Highlights: ? The N–F-codoped TiO2 films were prepared on FTO substrate by liquid-phase-deposition. ? The TiO2 films showed a visible-light response in the wavelength of 600–750 nm. ? The TiO2 film exhibited an effective photogenerated cathodic protection for 304SS. - Abstract: The liquid-phase-deposition (LPD) method was developed to prepare N–F-codoped TiO2 films that served as photoanodes for the cathodic protection of SUS304 stainless steel (304SS). The as-prepared LPD-TiO2 films were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Photoelectrochemical properties, such as open-circuit potential (OCP), photocurrent spectra, Tafel polarization curves and electrochemical impedance spectroscopy (EIS) of the LPD-TiO2 films, were also measured. The results indicate that the LPD-TiO2 films showed a visible-light response in the wavelength range of 600–750 nm. The photocurrent intensities in both the ultraviolet (UV)-light and visible-light regions were enhanced as the heat treatment (HT) temperature increased. However, the as-prepared LPD-TiO2 films exhibited the most negative photopotential under both visible-light and white-light illumination. In conclusion, the as-prepared LPD-TiO2 films would provide the most effective photogenerated cathodic protection of 304SS.304SS.

  17. Elaboration of TiO2 films by PECVD for use in photocatalysis

    International Nuclear Information System (INIS)

    We present the first results in the production of films of titanium dioxide (TiO2) deposited by Plasma enhanced chemical vapor deposition (PECVD). The films are destined for use in photocatalysis for water treatment. The deposits were made on glass from titanium isopropoxide as precursor (Ti[OCH(CH3)2]4) and a controlled flow of O2. The films were grown at room temperature and 300oC to compare properties. The characterization of the deposits was performed using scanning electron microscopy, UV-visible transmittance and infrared absorbance. The deposits were obtained with very good adhesion to substrates showing energy values of band gap of 2.83 eV

  18. In situ spectroscopic ellipsometry study of TiO2 films deposited by plasma enhanced chemical vapour deposition

    International Nuclear Information System (INIS)

    TiO2 thin films of 300–400 nm were deposited at low pressure (3 mTorr) and temperature (b). The impact of growth interruptions on the film characteristics was studied by in situ spectroscopic ellipsometry (SE), scanning electron microscopy (SEM) and X-ray diffraction. The interruptions were carried out by stopping the plasma generation and gas injection once the increase of the layer thickness during each deposition step was about 100 nm. Suitable ellipsometric models were built to account for the structural and optical differences among the layers grown at different stages. When no bias is applied or Vb = ?10 V, the films deposited with and without interruptions are composed of a dense layer near substrate, an intermediate gradient layer and a top roughness layer. But the growth interruptions result in an increase of the dense layer thickness and a decrease of surface roughness. The discrepancy of the refractive index measured by SE between bottom and upper layers can be reduced by growth interruptions or biasing the substrate. In the case of Vb = ?50 V, the film becomes well organized, the top surface appears smoother, and the refractive index can be increased greatly, without significant effect of growth interruptions.

  19. Spectroscopic ellipsometry analysis of TiO2 films deposited by plasma enhanced chemical vapor deposition in oxygen/titanium tetraisopropoxide plasma

    International Nuclear Information System (INIS)

    TiO2 thin films were deposited at low pressure and temperature on silicon substrates using plasma enhanced chemical vapor deposition in oxygen rich O2/titanium tetraisopropoxide inductively coupled radiofrequency plasmas. The influence of substrate bias Vb (|Vb| ? 50 V) on the film properties was investigated. The results obtained by fitting ellipsometry spectra in the 1.5–6 eV range, using a three-sublayer physical model, are in good agreement with the film morphology when no bias is applied or Vb = ? 10 V. The refractive indices in the transparent range are enhanced at Vb = ? 50 V, according to a physical model which only includes a homogenous layer and a top roughness layer. Scanning electron microscopic views show that all the films exhibit a columnar structure, but layer compactness and organization increase with the bias. The film structure evolution as a function of Vb is also evidenced on the refractive index dispersion curves. Complementary X-ray diffraction and Fourier transform infrared spectroscopy measurements show that films are basically amorphous mixed with a small amount of anatase at the floating potential (Vb = 0), whereas applying a bias voltage leads to the enhancement of anatase phase and the appearance of rutile phase (Vb = ? 50 V). - Highlights: ? Plasma enhanced chemical vapor deposited TiO2 films ? Biasing effect on the lms ? Biasing effect on the structural and optical film properties ? Ellipsometric modeling with a gradient index sublayer ? Good agreement between ellipsometry analysis and scanning electron microscopy

  20. Full mineralization of toluene by photocatalytic degradation with porous TiO2/SiC nanocomposite film

    International Nuclear Information System (INIS)

    Graphical abstract: In humid condition, the surface of TiO2 was covered by a water layer, but the surface of SiC keeps uncovered (as shown in the left part of the following picture). Due to the special staggered type energy band structure heterojunction, the photogenerated electrons gathered on TiO2 and holes enriched on SiC. Both of which participated in the degradation of toluene in different ways (as shown in the right part of the following picture). Highlights: ? To fully photocatalytic oxidize toluene in high concentration is a great challenge. ? Hydrophobic SiC is coupled with hydrophilic TiO2 to enhance the mineralization. ? The separation of the photogenerated electron?hole pairs was promoted. ? Electrons and holes participate in the degradation independently. ?Toluene is decomposed and fully mineralized. -- Abstract: Photocatalysis is a promising technique to fully decompose toluene and other volatile organic compounds (VOCs). In this work, porous TiO2/SiC nanocomposite films were synthesized by ball-milling and screen printing technique. Their photocatalytic properties in the degradation of toluene were carried out in a self-made reactor system. It was found that, in dry condition, the mineralization ratio of toluene by TiO2/SiC nanocomposite increased to 1.61 times comparing with pure TiO2. What is more, when TiO2/SiC nanocomposite was applied in humid condition the mineralization ratio increased to nearly fivefold that of pure TiO2 in dry, up to 100% of mineralization. These results were smoothly explained by the synergistic effect of TiO2–SiC heterojunction and the interaction between water and TiO2 (SiC). Due to the special staggered type energy band structure heterojunction, the photogenerated electrons gathered on TiO2 and holes enriched on SiC. Both of which participated in the degradation of toluene in more efficient ways and owing to the hydrophilicity of TiO2 and hydrophobicity of SiC, the mineralization capacity of photogenerated electrons and holes was largely promoted. The final results indicated that the hydrophilicity (hydrophobicity) of photocatalyst must be taken into account in gas-phase photocatalytic degradation

  1. Soporte de Nuevas Películas de TiO2 y TiO2/SiO2 sobre Gránulos de Poliéster para Aplicación en Fotocatálisis / Support of New TiO2 and TiO2/SiO2 Films on Polyester Granules for Photocatalytic Applications

    Scientific Electronic Library Online (English)

    Juan M, Marín; José A, Navío; Luis A, Rios; Gloria, Restrepo.

    Full Text Available Películas de TiO2 o TiO2/SiO2 fueron soportadas sobre gránulos de poliéster usando mecanismos de difusión y posterior tratamiento térmico a 100ºC. Se emplearon dos clases de geles. El primero fue preparado usando diferentes cantidades de TiO2, cloruro de metileno y silicona líquida. El segundo fue o [...] btenido por medio del método sol-gel, empleado para producir una matriz de sílice a partir de la hidrólisis el tetraetilo ortosilicato, en un medio orgánico de 2-propanol, en el cual se dispersó el fotocatalizador. Los precursores de cada sistema fueron agregados en diferentes relaciones para determinar su influencia en la estabilidad, propiedades y fotoactividad de las películas. La actividad fotocatalítica fue evaluada en la fotodegradación de metanol en fase gaseosa. Los resultados muestran la producción de materiales con alta resistencia, funcionalidad y actividad así como una fuerte relación entre la actividad fotocatalítica con las propiedades fisicoquímicas. Abstract in english Films of TiO2 and of TiO2/SiO2 were supported on polyester granules using a diffusion mechanism and a posterior thermal treatment to 100ºC. Two kinds of gels were used. The first one was prepared using different amounts of TiO2, methylene chloride and liquid silicone. The second one used the sol-gel [...] method to produce a silica matrix by adding tetraethyl orthosilicate, water and 2- propanol. After that the photocatalyst was dispersed in the gel. The precursors of each system were added in different amounts to determine their influence in the stability, properties and photoactivity of the films. The photocatalytic activity was tested in the methanol photodegradation in gas phase. The results show the production of materials with high resistance, functionality and activity as well as a strong dependence between the photocatalityc activity and efficiency with the physicochemical properties of the films.

  2. Soporte de Nuevas Películas de TiO2 y TiO2/SiO2 sobre Gránulos de Poliéster para Aplicación en Fotocatálisis Support of New TiO2 and TiO2/SiO2 Films on Polyester Granules for Photocatalytic Applications

    Directory of Open Access Journals (Sweden)

    Juan M Marín

    2008-01-01

    Full Text Available Películas de TiO2 o TiO2/SiO2 fueron soportadas sobre gránulos de poliéster usando mecanismos de difusión y posterior tratamiento térmico a 100ºC. Se emplearon dos clases de geles. El primero fue preparado usando diferentes cantidades de TiO2, cloruro de metileno y silicona líquida. El segundo fue obtenido por medio del método sol-gel, empleado para producir una matriz de sílice a partir de la hidrólisis el tetraetilo ortosilicato, en un medio orgánico de 2-propanol, en el cual se dispersó el fotocatalizador. Los precursores de cada sistema fueron agregados en diferentes relaciones para determinar su influencia en la estabilidad, propiedades y fotoactividad de las películas. La actividad fotocatalítica fue evaluada en la fotodegradación de metanol en fase gaseosa. Los resultados muestran la producción de materiales con alta resistencia, funcionalidad y actividad así como una fuerte relación entre la actividad fotocatalítica con las propiedades fisicoquímicas.Films of TiO2 and of TiO2/SiO2 were supported on polyester granules using a diffusion mechanism and a posterior thermal treatment to 100ºC. Two kinds of gels were used. The first one was prepared using different amounts of TiO2, methylene chloride and liquid silicone. The second one used the sol-gel method to produce a silica matrix by adding tetraethyl orthosilicate, water and 2- propanol. After that the photocatalyst was dispersed in the gel. The precursors of each system were added in different amounts to determine their influence in the stability, properties and photoactivity of the films. The photocatalytic activity was tested in the methanol photodegradation in gas phase. The results show the production of materials with high resistance, functionality and activity as well as a strong dependence between the photocatalityc activity and efficiency with the physicochemical properties of the films.

  3. A new coral structure TiO2/Ti film electrode applied to photoelectrocatalytic degradation of Reactive Brilliant Red

    International Nuclear Information System (INIS)

    A novel structure TiO2/Ti film was prepared on a titanium matrix using anodic oxidation technique and applied to degrade Reactive Brilliant Red (RBR) dye in simulative textile effluents. The film was characterized by Field-Emission Scanning Electron Microscope (FE-SEM), Laser Micro-Raman Spectrometer (LMRS), UV-vis spectrophotometer (UVS) and Photoelectrocatalytic (PEC) experiment. The results show that the surface morphology of the film is coral structure, and the crystal structure of the film is anatase. The absorbency of the coral structure TiO2/Ti film is 87-93% in the UV light region, and 77-87% in the visible light region. PEC experiment indicates that the photocurrent density of the coral structure TiO2/Ti film electrode achieves 160 ?A/cm2. The color and Chemical Oxygen Demand (COD) removal efficiencies of RBR achieve 73% and 60% in 1 h, respectively. These are 16% and 58% higher than those of nanotube TiO2/Ti film electrode. These were attributed to that these electrodes with different surface morphologies exhibit distinct surface areas and light absorption rate.

  4. Low-temperature preparation of F-doped TiO2 film and its photocatalytic activity under solar light

    International Nuclear Information System (INIS)

    A novel and simple method for preparing F-doped anatase TiO2 (defined as FTO) film with high photocatalytic activity was developed using titanium-n-butoxide and NH4F as TiO2 and fluorine precursors under mild condition, i.e. low temperature (lower than 373 K) and ambient pressure. The prepared samples were characterized by XRD, SEM, X-ray photoelectron spectroscopy (XPS), diffuse reflectance spectrum (DRS), photoluminescence spectrum (PL) and TG-DSC analysis. The photocatalytic activity was evaluated by decomposing X-3B under artificial solar light. The results showed that the crystallinity of TiO2 was improved by F-doping. F- ions can prevent the grain growth, and the transformation of anatase to rutile phase was also inhibited. The doped fluorine atoms existed in two chemical forms, and the ones incorporated into TiO2 lattice might take a positive role in photocatalysis. Compared with surface fluorination samples, FTO film exhibited better photocatalytic activity. The high photocatalytic activity of FTO may due to extrinsic absorption through the creation of oxygen vacancies rather than the excitation of the intrinsic absorption band of bulk TiO2. Furthermore, the FTO can be recycled with little photocatalytic activity depression. Without any further treatment besides rinsing, after 6 recycle utilization, the photocatalytic activity of FTO film was still higher than 79%still higher than 79%

  5. TiO2 films with rich bulk oxygen vacancies prepared by electrospinning for dye-sensitized solar cells

    Science.gov (United States)

    Li, Xiaodong; Gao, Caitian; Wang, Jiangtao; Lu, Bingan; Chen, Wanjun; Song, Jie; Zhang, Shanshan; Zhang, Zhenxing; Pan, Xiaojun; Xie, Erqing

    2012-09-01

    Highly transparent nanocrystalline TiO2 films have been fabricated by electrospinning (ES) technique based on a transmutation process from as-spun nanofibers with an appropriate amount of tri-ethanolamine (TEOA) added to the precursor. A possible evolution mechanism of the transparent nanocrystalline TiO2 films is proposed. It is found that the films prepared via transmutation from electrospun nanofibers possess rich bulk oxygen vacancies (BOVs, PL band at 621-640 nm) by using photoluminescence (PL) spectroscopy. Contrastively, the dominant peak in PL spectrum of the spin-coated film is the emission from surface oxygen vacancies (SOVs, PL band at 537-555 nm). The electrospun TiO2 films with rich BOVs induce large open-circuit voltage (Voc) and fill factor (FF) improvements in dye-sensitized solar cells (DSCs), and thus a large improvement of energy conversion efficiency (?). In addition, these performance advantages are maintained for a double-layer cell with a doctor-bladed ?7 ?m top layer (P25 nanometer TiO2, Degussa) and an electrospun ?3 ?m bottom layer. The double-layer cell yields a high ? of 6.01%, which has increased by 14% as compared with that obtained from a 10 ?m thick P25 film.

  6. Wet etching of optical thin films

    OpenAIRE

    Edstro?m, Curt

    2010-01-01

    Evaluation of the wet etching properties of several different thin film oxidesgrown by physical vapour deposition was performed in this work. MgO, Al2O3,SiO2, TiO2, HfO2 ZrO2 and Y2O3 were coated on two types of substrates; Si andborosilicate glass and etching tests were performed in different etchingsolutions. MgF2 thin films have also been evaluated. Important aspects of the choice of the thin films was taken into account in orderto match to good optical properties such as refractive index ...

  7. Deposition of transparent, hydrophobic polydimethylsiloxane - nanocrystalline TiO2 hybrid films on glass substrate

    Directory of Open Access Journals (Sweden)

    On-uma Nimittrakoolchai

    2010-05-01

    Full Text Available Transparent, hydrophobic hybrid films were deposited on glass substrate from solution containing hydroxyl-terminatedpolydimethylsiloxane (PDMS and TiO2 sol by using a dip coating method. The effects of the film heat-treatment temperatureand PDMS/TiO2 component on surface properties of the hybrid films were investigated by water drop contact angle measurement,and by atomic force microscopy (AFM and scanning electron microscope (SEM analyses. Surface morphology of the hybrid film changed from smooth surface containing tiny spikes to rougher surface containing large protrusions during heattreatmenttemperatures of 60 - 300°C and became smooth surface containing very fine spikes at 500°C, corresponding to a change hydrophobicity behavior from contact angle measurement. The suitable condition for preparation of hydrophobic coating from this current recipe was at the PDMS/TiO2 volume ratio of 1.00 - 2.33 and heat-treatment temperature of 60°C. All the films were transparent regardless of post heat-treatment temperature. However, the films containing higher content of PDMS were slightly more transparent.

  8. Growth and investigation of TiO2 and AlN nanostructure’s properties

    Directory of Open Access Journals (Sweden)

    A. Bahari

    2008-03-01

    Full Text Available  We have grown TiO2 and AlN under ultra high vacuum and high pressure conditions and studied their structures with using AES and SEM techniques. The obtained results show that an amorphous film of TiO2 and AlN could be formed on silicon substrate. Furthermore, TiO2 and AlN are high – K dielectric materials and they can thus be replaced to ultra thin gate oxide film.

  9. TiO2 film/Cu2O microgrid heterojunction with photocatalytic activity under solar light irradiation.

    Science.gov (United States)

    Zhang, Junying; Zhu, Hailing; Zheng, Shukai; Pan, Feng; Wang, Tianmin

    2009-10-01

    Coupling a narrow-band-gap semiconductor with TiO(2) is an effective method to produce photocatalysts that work under UV-vis light irradiation. Usually photocatalytic coupled-semiconductors exist mainly as powders, and photocatalytic activity is only favored when a small loading amount of narrow-band-gap semiconductor is used. Here we propose a heavy-loading photocatalyst configuration in which 51% of the surface of the TiO(2) film is covered by a Cu(2)O microgrid. The coupled system shows higher photocatalytic activity under solar light irradiation than TiO(2) and Cu(2)O films. This improved performance is due to the efficient charge transfer between the two phases and the similar opportunity each has to be exposed to irradiation and adsorbates. PMID:20355842

  10. Thin carbon layer coated Ti3+-TiO2 nanocrystallites for visible-light driven photocatalysis

    Science.gov (United States)

    Jiang, Baojiang; Tang, Yunqi; Qu, Yang; Wang, Jian-Qiang; Xie, Ying; Tian, Chungui; Zhou, Wei; Fu, Honggang

    2015-03-01

    Black TiO2 containing Ti3+ attracts enormous attention due to its excellent visible-light driven photocatalytic activity. Herein, an in situ thermal decomposition approach to synthesize uniform thin carbon coated Ti3+-TiO2 nanocrystals is presented. During the oleic acid-assisted solvothermal process, the crystal size and morphology of TiO2 were controlled through oleic acid with carboxylic acid groups. Then the residual small quantities of oleic acid anchored on TiO2 were used as a carbon source, which could be in situ pyrolyzed into a carbon layer on TiO2 at high temperature and under an inert atmosphere. Meanwhile, Ti4+ species were partly reduced into Ti3+ states/oxygen vacancies on the surface of TiO2 due to the carbothermal reduction reaction for the carbon-encapsulated Ti3+-TiO2 structure. A series of characterizations indicated that the 20-25 nm TiO2 nanocrystals obtained were wrapped evenly by 1-2 nm carbon layers, which had an important effect on the energy band structure change of TiO2. The presence of the carbon layer also improves the Ti3+ stability and the conduction behavior of the composites. The Ti3+ states/oxygen vacancies created on the surface of TiO2 were responsible for the remarkable photogenerated charge separation and extended visible-light absorption range. Furthermore, Ti3+ states/oxygen vacancies and the carbon layer together could enhance the adsorption ability of O2 so as to promote the photogenerated electrons captured by the adsorbed O2, leading to a great increase in the charge separation. As a result, the composites exhibit high photocatalytic performance for organic pollutants under visible light irradiation. This simple and new method may pave the way to practical applications for efficient photocatalytic degradation under visible light.Black TiO2 containing Ti3+ attracts enormous attention due to its excellent visible-light driven photocatalytic activity. Herein, an in situ thermal decomposition approach to synthesize uniform thin carbon coated Ti3+-TiO2 nanocrystals is presented. During the oleic acid-assisted solvothermal process, the crystal size and morphology of TiO2 were controlled through oleic acid with carboxylic acid groups. Then the residual small quantities of oleic acid anchored on TiO2 were used as a carbon source, which could be in situ pyrolyzed into a carbon layer on TiO2 at high temperature and under an inert atmosphere. Meanwhile, Ti4+ species were partly reduced into Ti3+ states/oxygen vacancies on the surface of TiO2 due to the carbothermal reduction reaction for the carbon-encapsulated Ti3+-TiO2 structure. A series of characterizations indicated that the 20-25 nm TiO2 nanocrystals obtained were wrapped evenly by 1-2 nm carbon layers, which had an important effect on the energy band structure change of TiO2. The presence of the carbon layer also improves the Ti3+ stability and the conduction behavior of the composites. The Ti3+ states/oxygen vacancies created on the surface of TiO2 were responsible for the remarkable photogenerated charge separation and extended visible-light absorption range. Furthermore, Ti3+ states/oxygen vacancies and the carbon layer together could enhance the adsorption ability of O2 so as to promote the photogenerated electrons captured by the adsorbed O2, leading to a great increase in the charge separation. As a result, the composites exhibit high photocatalytic performance for organic pollutants under visible light irradiation. This simple and new method may pave the way to practical applications for efficient photocatalytic degradation under visible light. Electronic supplementary information (ESI) available: XRD, Raman, FT-IR, XPS, ESR, and photoactivity measurements. See DOI: 10.1039/c5nr00032g

  11. Thin Films.

    Czech Academy of Sciences Publication Activity Database

    Šolcová, Olga

    Maribor : Univerza v Mariboru, 2013. [Nanofuture. Maribor (SI), 03.02.2013-07.02.2013] R&D Projects: GA TA ?R TA01020804 Institutional support: RVO:67985858 Keywords : sol-gel methods * thin films * nannomaterials Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  12. Generación de estados superficiales durante la formación electroforética catódica de películas de TiO2 sobre ito Surface states generation during cathodic electrophoretic deposition of TiO2/ito films

    Directory of Open Access Journals (Sweden)

    Próspero Acevedo-Peña

    2011-01-01

    Full Text Available In the present work TiO2 films were formed over Indium Tin Oxide (ITO employing cathodic electrophoretic deposition (Cathodic-EPD and Dr. Blade Technique. The films were characterized by electrochemical techniques in order to compare their electronic properties; as well as, their photoelectrochemical behavior. The electrochemical performance showed by the films, allowed to relate the modification occurring during the Cathodic-EPD, with the partial reduction of TiO2 nanoparticles, generating Ti3+ defects. These trapping states are modifying the electronic properties of the film, and diminishing the transport of the photoelectrogenerated electrons toward ITO.

  13. Generación de estados superficiales durante la formación electroforética catódica de películas de TiO2 sobre ito / Surface states generation during cathodic electrophoretic deposition of TiO2/ito films

    Scientific Electronic Library Online (English)

    Próspero, Acevedo-Peña; Ignacio, González; Gerardo, Vázquez; J., Manríquez.

    Full Text Available [...] Abstract in english In the present work TiO2 films were formed over Indium Tin Oxide (ITO) employing cathodic electrophoretic deposition (Cathodic-EPD) and Dr. Blade Technique. The films were characterized by electrochemical techniques in order to compare their electronic properties; as well as, their photoelectrochemi [...] cal behavior. The electrochemical performance showed by the films, allowed to relate the modification occurring during the Cathodic-EPD, with the partial reduction of TiO2 nanoparticles, generating Ti3+ defects. These trapping states are modifying the electronic properties of the film, and diminishing the transport of the photoelectrogenerated electrons toward ITO.

  14. Multi-modal TiO2-LaFeO3 composite films with high photocatalytic activity and hydrophilicity

    International Nuclear Information System (INIS)

    In this paper, a series of multi-modal TiO2-LaFeO3 composite films have been successfully synthesized through a two-step method. The resultant films were characterized in detail by several testing techniques, such as X-ray diffraction (XRD), ultraviolet-visible diffuse reflection spectrum (UV-vis DRS), photoluminescence spectrum (PL), surface photovoltage spectroscopy (SPS) and water contact angle measurements. The photocatalytic activity of different films was evaluated for degrading Methylene Blue (MB) aqueous solution. Hydrophilicity of the obtained TiO2-LaFeO3 composite films was also investigated. The results show that TL film and LT film exhibited superior photocatalytic activity and hydrophilicity.

  15. Fabrication and photoelectrochemical properties of TiO2 films on Ti substrate for flexible dye-sensitized solar cells

    International Nuclear Information System (INIS)

    The dye-sensitized solar cells (DSSCs) using Ti foil supporting substrate for fabricating nanocrystalline TiO2 flexible film electrodes were developed, intending to improve the photoelectrochemical properties of flexible substrate-based DSSCs. The obtained cells were characterized by electrochemical impedance spectra (EIS), open circuit voltage decay (OCVD) measurement and Tafel plots. The experimental results indicate that the most important advantage of a Ti foil-based TiO2 flexible electrode over a FTO glass-based electrode lies in its reduced sheet resistance, electron traps, and the retarded back reaction of electrons with tri-iodine ions in DSSCs. All above characteristics for the Ti substrate TiO2 films are beneficial for decreasing the charge recombination in the TiO2 electrode and prolonging the electron lifetimes for the DSSCs, as well as improvement of the overall solar conversion efficiency. The photocurrent of the cell fabricated with the Ti foil-based flexible electrode increased significantly, leading to a much higher overall solar conversion efficiency of 5.45% at 100 mW/cm2 than the cell made with FTO glass-based TiO2 electrodes. Above results demonstrate that Ti foil is a potential alternative to the conventional FTO glass substrate for the DSSCs.

  16. Band-gap narrowing of TiO2 films induced by N-doping

    International Nuclear Information System (INIS)

    N-doped TiO2 films were deposited on n + -GaN/Al2O3 substrates by reactive magnetron sputtering and subsequently crystallized by annealing at 550 oC in flowing N2 gas. The N-doping concentration was ?8.8%, as determined from X-ray photoelectron spectroscopy measurements. Deep-level optical spectroscopy measurements revealed two characteristic deep levels located at 1.18 and 2.48 eV below the conduction band. The 1.18 eV level is probably attributable to the O vacancy state and can be active as an efficient generation-recombination center. Additionally, the 2.48 eV band is newly introduced by the N-doping and contributes to band-gap narrowing by mixing with the O 2p valence band

  17. Effects of pico-to-nanometer-thin TiO2 coating on the biological properties of microroughened titanium.

    Science.gov (United States)

    Sugita, Yoshihiko; Ishizaki, Ken; Iwasa, Fuminori; Ueno, Takeshi; Minamikawa, Hajime; Yamada, Masahiro; Suzuki, Takeo; Ogawa, Takahiro

    2011-11-01

    The independent, genuine role of surface chemistry in the biological properties of titanium is unknown. Although microtopography has been established as a standard surface feature in osseous titanium implants, unfavorable behavior and reactions of osteogenic cells are still observed on the surfaces. To further enhance the biological properties of microfeatured titanium surfaces, this study tested the hypotheses that (1) the surface chemistry of microroughened titanium surfaces can be controllably varied by coating with a very thin layer of TiO(2), without altering the existing topographical and roughness features; and (2) the change in the surface chemistry affects the biological properties of the titanium substrates. Using a slow-rate sputter deposition of molten TiO(2) nanoparticles, acid-etched microroughened titanium surfaces were coated with a TiO(2) layer of 300-pm to 6.3-nm thickness that increased the surface oxygen levels without altering the existing microtopography. The attachment, spreading behavior, and proliferation of osteoblasts, which are considered to be significantly impaired on microroughened surfaces compared with relatively smooth surfaces, were considerably increased on TiO(2)-coated microroughened surfaces. The rate of osteoblastic differentiation was represented by the increased levels of alkaline phosphatase activity and mineral deposition as well as by the upregulated expression of bone-related genes. These biological effects were exponentially correlated with the thickness of TiO(2) and surface oxygen percentage, implying that even a picometer-thin TiO(2) coating is effective in rapidly increasing the biological property of titanium followed by an additional mild increase or plateau induced by a nanometer-thick coating. These data suggest that a super-thin TiO(2) coating of pico-to-nanometer thickness enhances the biological properties of the proven microroughened titanium surfaces by controllably and exclusively modulating their surface chemistry while preserving the existing surface morphology. The improvements in proliferation and differentiation of osteoblasts attained by this chemical modification is of great significance, providing a new insight into how to develop new implant surfaces for better osseointegration, based on the established microtopographic surfaces. PMID:21840046

  18. Structural, Optical and Morphological Properties of TiO2/Ag/TiO2 Multilayer Films

    Science.gov (United States)

    Hasan, M. M.; Haseeb, A. S. M. A.; Saidur, R.; Masjuki, H. H.; Johan, M. R.

    2009-06-01

    In this investigation, TiO2/Ag/TiO2 multilayer-films were deposited on microscope glass slides with varying individual layer thicknesses by radio-frequency reactive magnetron sputtering. Prior to multilayer development, single layers of Ag and TiO2 were deposited and characterized. All the films were prepared at a moderately high pressure at room temperature. It was found that single layer of TiO2 showed anatase polycrystalline structure. It also exhibited high visible transmittance of above 80% and higher refractive index of 2.31 at a wavelength of 550 nm. The indirect optical band gap of the TiO2 films was estimated as 3.39 eV. The Ag single layer films were found to be crystalline with a very high reflectance for IR (Infra-red) light. Finally, the multilayers have been deposited and characterized by X-ray diffraction, UV-visible-IR spectrophotometry, scanning electron microscopy and profilometry.

  19. Photocatalytic and photoelectrochemical properties of sol–gel TiO2 films of controlled thickness and porosity.

    Czech Academy of Sciences Publication Activity Database

    Krýsa, J.; Baudyš, M.; Zlámal, M.; Krýsová, Hana; Morozová, Magdalena; Kluso?, Petr

    2014-01-01

    Ro?. 230, JUL 2014 (2014), s. 2-7. ISSN 0920-5861 Institutional support: RVO:61388955 ; RVO:67985858 Keywords : TiO2 film * Sol-gel * Thickness Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.309, year: 2013

  20. Characterization and mechanical investigation of Ti–O2?x film prepared by plasma immersion ion implantation and deposition for cardiovascular stents surface modification

    International Nuclear Information System (INIS)

    Highlights: ? We prepared Ti–O2?x films of good quality by PIII and D successfully on stents product. ? The Ti–O2?x film shows good homogeneity and intergradient film/substrate interface. ? The Ti–O2?x films on stent sustain clinically-required expansion without failure. ? The films show good mechanical durability for cardiovascular stents application. - Abstract: Up to date, materials for cardiovascular stents are still far from satisfactory because of high risk of biomaterials-associated restenosis and thrombosis. Extensive efforts have been made to improve the biocompatibility of the materials by various surface modification techniques. Ti–O2?x films prepared by plasma immersion ion implantation and deposition (PIII and D) have shown good blood compatibility. For clinical application, surface quality and mechanical durability of the Ti–O2?x film on stents are also of critical importance for the long-term serving. In this paper we present our research results on surface quality, mechanical investigation and characterization of Ti–O2?x films prepared using PIII and D on stent products provided by Boston Scientific SCIMED. Ti–O2?x films with mostly Rutile and little non-stoichiometric phases were obtained with smoothness of 2?x films on stents produducts were sustained balloon-expansion of clinically-required extent without mechanical failure, showing highly potential feasibility for cardiovascular stents application.