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Sample records for nanostructured tio2 films

  1. 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

    2015-01-01

    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.

  2. Robust superamphiphobic film from electrospun TiO2 nanostructures.

    Science.gov (United States)

    Ganesh, V Anand; Dinachali, Saman Safari; Nair, A Sreekumaran; Ramakrishna, Seeram

    2013-03-13

    Rice-shaped TiO2 nanostructures are fabricated by electrospinning for creating a robust superamphiphobic coating on glass substrates. The as-fabricated TiO2 nanostructures (sintered at 500 °C) are superhydrophilic in nature which upon silanization turn into superamphiphobic surface with surface contact angle (SCA) values achieved using water (surface tension, γ = 72.1 mN/m) and hexadecane (surface tension, γ = 27.5 mN/m) being 166° and 138.5°, respectively. The contact angle hysteresis for the droplet of water and hexadecane are measured to be 2 and 12°, respectively. Thus, we have successfully fabricated superior self-cleaning coatings that possess exceptional superamphiphobic property by employing a simple, cost-effective, and scalable technique called electrospinning. Furthermore, the coating showed good mechanical and thermal stability with strong adherence to glass surface, thus revealing the potential for real applications.

  3. Sandwich structure of Pd doped nanostructure TiO2 film as O2 sensor.

    Science.gov (United States)

    Wang, Hairong; Sun, Quantao; Chen, Lei; Zhao, Yulong

    2013-09-01

    In this paper, we investigated the sensing properties of sandwich structure of TiO2/Pd/TiO2 thin films at various operating temperatures and oxygen partial pressures. The nanostructure TiO2 thin films were prepared by the sol-gel method. Various thickness of Pd buried layer was deposited by magnetron sputtering of a pure Pd target. The films were characterized using X-ray diffraction analysis and SEM. It was found that TiO2/Pd/TiO2 thin films have the p-type behavior while the pure TiO2 thin film is n-type semiconductor materials. We found that the structure of TiO2/Pd/TiO2 thin films with 10 s sputtering Pd layer has a better stability at 240 °C.

  4. 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.

  5. CVD elaboration of nanostructured TiO2-Ag thin films with efficient antibacterial properties

    OpenAIRE

    Mungkalasiri, Jitti; Bedel, Laurent; Emieux, Fabrice; Dore, Jeanne; Renaud, François N. R.; Sarantopoulos, Christos; Maury, Francis

    2010-01-01

    Nanostructured TiO2-Ag composite coatings are deposited by direct liquid injection metal-organic (DLI-MO) CVD at 683K in a one-step process. Silver pivalate (AgPiv) and titanium tetra-iso-propoxide (TTIP) are used as Ag and Ti molecular precursors, respectively. Metallic silver nanoparticles are co-deposited with anatase TiO2 on stainless steel, glass, and silicon wafers. The silver particles are uniformly embedded in the oxide matrix through the entire film thickness. The influence of the gr...

  6. Sprayed nanostructured TiO2 films for efficient photocatalytic degradation of textile azo dye.

    Science.gov (United States)

    Stambolova, Irina; Shipochka, Capital Em Cyrillicaria; Blaskov, Vladimir; Loukanov, Alexandrе; Vassilev, Sasho

    2012-12-05

    Spray pyrolysis procedure for preparation of nanostructured TiO(2) films with higher photocatalytic effectiveness and longer exploitation life is presented in this study. Thin films of active nanocrystalline TiO(2) were obtained from titanium isopropoxide, stabilized with acetyl acetone and characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The activity of sprayed nanostructured TiO(2) is tested for photocatalytic degradation of Reactive Black 5 dye with concentrations up to 80 ppm. Interesting result of the work is the reduction of toxicity after photocatalytic treatment of RB5 with TiO(2), which was confirmed by the lower percentage of mortality of Artemia salina. It was proved that the film thickness, conditions of post deposition treatment and the type of the substrate affected significantly the photocatalytic reaction. Taking into account that the parameters are interdependent, it is necessary to optimize the preparation conditions in order to synthesize photocatalytic active films. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. Photocatalytic Properties of Columnar Nanostructured TiO2 Films Fabricated by Sputtering Ti and Subsequent Annealing

    Directory of Open Access Journals (Sweden)

    Zhengcao Li

    2012-01-01

    Full Text Available Columnar nanostructured TiO2 films were prepared by sputtering Ti target in pure argon with glancing angle deposition (GLAD and subsequent annealing at 400°C for different hours in air. Compared with sputtering TiO2 target directly, sputtering Ti target can be carried out under much lower base pressure, which contributes to obtaining discrete columnar nanostructures. In the present study, TiO2 films obtained by annealing Ti films for different hours all kept discrete columnar structures as the Ti films deposited in GLAD regime. The longer the annealing time was, the better the phase transition accomplished from Ti to TiO2 (a mixture of rutile and anatase, and the better it crystallized. In addition, those TiO2 films performed photocatalytic decolorization effectively and showed a law changing over annealing time under UV light irradiation towards methyl orange, which demonstrated the potential applications for treatment of effluent.

  8. Nanostructured TiO2 thin films for DSSCs prepared by sol gel technique

    Science.gov (United States)

    Bakar, Siti Noraini Abu; Abdullah, Huda; Mahbor, Kamisah Mohamad

    2017-07-01

    In this research, nanostructured TiO2 thin films were prepared by sol-gel technique for dye-sensitized solar cells (DSSCs) were investigated. The nanostructured thin films were prepared using commercial Titania powder (Degussa P25) and titanium (IV) ethoxide (TEOT). The resulting solution were spin-coated on pieces of indium-doped tin oxide (InO2:Sn, ITO) transparent glass (8 Ω/sq, TEC GlassTM) with an area of 10 × 10 mm2 at a rate of 2000 rpm for 30 seconds. The films were annealed in furnace at 450 °C for 60 min. The working electrode was then immersed in the solution of N-719 (Ruthenium) dye at room temperature for 24 h. A thin film of platinum (Pt) was deposited on the ITO-glass substrate as the counter electrode using print-screen technique. The structures, morphological and optical properties of the films, were examined using X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) and UV-VIS spectrometer respectively. The XRD results showed that the crystalline phase of the film was anatase. The micrograph obtained using FESEM demonstrated that the prepared TiO2 film has a nanosructured characteristic. The photovoltaic properties of DSSC was studied under an incident irradiation of 100 mW/cm2. The energy conversion efficiency (η) of the DSSC with nanostuctured TiO2 (P25) and TiO2 was 0.3% and 0.2 % respectively.

  9. Photocatalytic activity of nanostructured TiO2 thin films prepared by pulsed spray pyrolysis

    OpenAIRE

    López, Alcides; Acosta, Dwight; Martínez, Arturo

    2006-01-01

    Nano-structured TiO2 thin films were deposited onto soda lime glass by the pneumatic spray pyrolysis method from a peroxo-titanium complex solution. Samples were prepared spraying 10 s the complex solution followed by an interruption of 20 s in order to avoid inadequate substrate cooling, the substrate temperature was varied from 230 to 430 °C in 50 °C steps. Amorphous as-deposited films crystallized to the anatase phase after an annealing process at 500 °C for 3 h. The photocatalytic activit...

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

    OpenAIRE

    Akbar Eshaghi; Ameneh Eshaghi

    2012-01-01

    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, respecti...

  11. 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.

  12. Influence of annealing on optical and photovoltaic properties of nanostructured TiO2 films

    Science.gov (United States)

    Serikov, T. M.; Ibrayev, N. Kh; Smagulov, Zh Kh; Kuterbekov, К. А.

    2017-01-01

    Spectral and kinetic characteristics of the photoluminescence of TiO2 films obtained from TiO2 nanoparticles and nanotubes were studied. Luminescence spectra typical for the TiO2 with anatase structure were observed under UV excitation of the films. Heat treatment of the films at T=1273 K leads to a long-wavelength shift of the photoluminescence band with maximum at 850 nm, which corresponds to the rutile structure. The luminescence duration of rutile films is longer than the luminescence duration of the anatase films as for nanoparticles and for nanotubes. The photovoltaic properties of TiO2 films with different structures were investigated. It was established that anatase structured films have a higher photocurrent than the rutile structured film. By impedance spectroscopy method it was found that the electron transport resistance in the nanotube films is higher but the recombination rate is lower than in the TiO2 nanoparticle films.

  13. 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.

  14. Silver Doped TiO2 Nanostructure Composite Photocatalyst Film Synthesized by Sol-Gel Spin and Dip Coating Technique on Glass

    OpenAIRE

    Mojtaba Nasr-Esfahani; Mohammad Hossein Habibi

    2008-01-01

    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 500°C. The as-prepared TiO2 and TiO2/Ag films were characterized by X-ray diffractometry, a...

  15. Nanostructure Study of TiO2 Films Prepared by Dip Coating Process

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The microstructure properties of the sol-gel derived TiO2 films were studied by the atomic force microscopy (AFM).The films were prepared by dip coating process. The optical properties of the films were explained on the basis ofthe microstructure of the films.

  16. Double-layered TiO2-SiO2 nanostructured films with self-cleaning and antireflective properties.

    Science.gov (United States)

    Zhang, Xintong; Fujishima, Akira; Jin, Ming; Emeline, Alexei V; Murakami, Taketoshi

    2006-12-21

    Dual function of self-cleaning and antireflection can be created in double-layered TiO2-SiO2 nanostructured films. The film were prepared by (1) layer-by-layer deposition of multilayered SiO2 nanoparticles with polydiallyldimethylammonium (PDDA) cations, (2) layer-by-layer deposition of multilayered titanate nanosheets with polications on PDDA/SiO2 multilayer films, and (3) burning out the polymer and converting titanate nanosheets into TiO2 by hearing at 500 degrees C. The as-prepared films, consisting of a porous SiO2 bottom layer and a dense TiO2 top layer, improved the transmittance of glass or quartz substrates, as demonstrated by transmission spectra collected at normal incidence. The photocatalytic properties of the films were studied by the change of the water contact angle together with the decay of the IR absorption of the hydrocarbon chain of octadecylphosphonic-acid-modified films under 2.6 mW cm-2 UV illumination. Both the antireflective and the photocatalytic properties of the films were dependent on the number of PDDA/nanosheet bilayers deposited. however, excellent surface wettability of the films for water was obtained, independent of the preparation conditions. The experimental findings are discussed in terms of the special structure of the double-layered nanostructured film.

  17. Effects of 1064 nm laser on the structural and optical properties of nanostructured TiO2 thin film

    Science.gov (United States)

    Aslam Farooq, W.; Atif, M.; Ali, Syed Mansoor; Fatehmulla, Amanullah; Aslam, M.

    2014-09-01

    TiO2 thin film has been widely used as photoelectrode in dye-sensitized solar cells. It can also be used in quantum dot synthesized solar cells. Study of its effects in different spectrum of light is important for its use in solar cells. We have reported effects of 1064 nm laser on the surface morphology, structural and optical properties of nanostructured TiO2 thin film deposited on glass substrates using sol-gel spin coating technique. Q-Switched Nd:YAG pulsed laser at various power densities is used in this study. Surface morphology of the film is investigated using X-ray diffraction (XRD) and atomic force microscopy technique. The XRD pattern of as deposited TiO2 thin film is amorphous and after laser exposure it became TiO2 anatase structure. Atomic force microscopy of the crystalline TiO2 thin film shows that the grain size increases by increasing laser power density. The calculations of the band gap are carried out from UV/Visible spectroscopy measurements with JASCO spectrometer. For laser power density of 25 MW/cm2 there is an increase in the transmission and it decreases at the value of 38 MW/cm2 and band gap decreases with increasing laser power density. Photoluminescence spectra of the crystalline TiO2 thin film indicate two broad peaks in the range of 415 and 463 nm, one for band gap peak (415 nm) and other for oxygen defect during film deposition process.

  18. Combined sonochemical/CVD method for preparation of nanostructured carbon-doped TiO2 thin film

    Science.gov (United States)

    Rasoulnezhad, Hossein; Kavei, Ghassem; Ahmadi, Kamran; Rahimipour, Mohammad Reza

    2017-06-01

    The present work reports the successful synthesis of the nanostructured carbon-doped TiO2 thin films on glass substrate by combination of chemical vapor deposition (CVD) and ultrasonic methods, for the first time. In this method the ultrasound waves act as nebulizer for converting of sonochemically prepared TiO2 sol to the mist particles. These mist particles were thermally decomposed in subsequent CVD chamber at 320 °C to produce the carbon-doped TiO2 thin films. The obtained thin films were characterized by means of X-ray Diffraction (XRD), Raman spectroscopy, diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and scanning electron microscopy (SEM) techniques. The results show that the prepared thin films have anatase crystal structure and nanorod morphology, which calcination of them at 800 °C results in the conversion of nanorods to nanoparticles. In addition, the prepared samples have high transparency, monodispersity and homogeneity. The presence of the carbon element in the structure of the thin films causes the narrowing of the band-gap energy of TiO2 to about 2.8 eV, which results in the improvement of visible light absorption capabilities of the thin film.

  19. Optical Spectra of Graded Nanostructured TiO2 Chiral Thin Films

    CERN Document Server

    Babaei, F; Savaloni, H; 10.1016/j.optcom.2010.03.005

    2010-01-01

    The rigorous coupled wave analysis method (RCWA) is applied to the graded chiral TiO2 thin films in axial and non-axial excited states using the Bruggeman homogenization formalism. The dependence of the filtering frequency and polarization selectivity as a function of different structural parameters, are investigated. A good agreement with experimental results reported by other researchers is achieved.

  20. Visible light catalysis of rhodamine B using nanostructured Fe(2)O(3), TiO(2) and TiO(2)/Fe(2)O(3) thin films.

    Science.gov (United States)

    Mahadik, M A; Shinde, S S; Mohite, V S; Kumbhar, S S; Moholkar, A V; Rajpure, K Y; Ganesan, V; Nayak, J; Barman, S R; Bhosale, C H

    2014-04-05

    The Fe(2)O(3), TiO(2) and TiO(2)/Fe(2)O(3) composite films are deposited using spray pyrolysis method onto glass and FTO coated substrates. The structural, morphological, optical and photocatalytic properties of Fe(2)O(3), TiO(2) and TiO(2)/Fe(2)O(3) thin films are studied. XRD analysis confirms that films are polycrystalline with rhombohedral and tetragonal crystal structures for Fe2O3 and TiO(2) respectively. The photocatalytic activity was tested for the degradation of Rhrodamine B (Rh B) in aqueous medium. The rate constant (-k) was evaluated as a function of the initial concentration of species. Substantial reduction in concentrations of organic species was observed from COD and TOC analysis. Photocatalytic degradation effect is relatively higher in case of the TiO(2)/Fe(2)O(3) than TiO(2) and Fe(2)O(3) thin film photoelectrodes in the degradation of Rh B and 98% removal efficiency of Rh B is obtained after 20min. The photocatalytic experimental results indicate that TiO(2)/α-Fe(2)O(3) photoelectrode is promising material for removing of water pollutants.

  1. Characterization of nanostructured TiO2:Ag films: structural and optical properties

    Science.gov (United States)

    Ivanova, T.; Harizanova, A.; Koutzarova, T.; Vertruyen, B.

    2016-10-01

    TiO2:Ag nanocomposites have been prepared by sol-gel method with varying silver concentration. Different technological approaches are employed to study the formation of Ag nanoparticles in titanium dioxide matrix. The obtained thin films are either thermally treated at temperatures from 300 to 600oC or UV irradiated for 15 minutes between layer deposition. XRD and FTIR studies reveal that Ag is incorporated in TiO2 films as nanoparticles and no Ag oxide phases are detected. Optical characterization performed by UV-VIS spectroscopy confirms the formation of silver nanoparticles. The influence of thermal treatment and UV radiation on the optical and structural properties is studied.

  2. Silver Doped TiO2 Nanostructure Composite Photocatalyst Film Synthesized by Sol-Gel Spin and Dip Coating Technique on Glass

    Directory of Open Access Journals (Sweden)

    Mojtaba Nasr-Esfahani

    2008-01-01

    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 500°C. 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 500°C 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.

  3. The effect of substrate temperature on the spray-deposited TiO2 nanostructured films for dye-sensitized solar cells.

    Science.gov (United States)

    Hossain, Md Faruk; Takahashi, Takakazu

    2011-04-01

    The nanostructured TiO2 films have deposited on SnO2:F (FTO) coated glass substrate by spray pyrolysis technique at different substrate temperatures of 200-500 degrees C. The structural, surface morphological and optical properties of TiO2 films significantly vary with the substrate temperature. The surface of the TiO2 films deposited at 400 degrees C shows the nanoflakes and short nanorods (approximately 130 nm) like structures while the TiO2 films prepared at 500 degrees C shows only the nanoflakes like structures. The band gap of the TiO2 films prepared at higher temperatures (300-500 degrees C) becomes narrow due to presence the rutile phases in their crystal structure. Ruthenium (II) complex as a dye, KI/I2 as an electrolyte and carbon on FTO glass as a counter electrode has used to fabricate the dye-sensitized solar cell (DSC). The TiO2 film deposited at 400 degrees C has showed the best photovoltaic performance in DSC with the efficiency of 3.81%, the photovoltage of 773 mV, the photocurrent of 8.34 mA/cm2, and the fill factor of 56.17%. The photovoltage of the DSC increases with the increase of substrate temperature during the deposition of TiO2 films. Moreover, all the DSCs exhibit reasonably high fill factor value.

  4. Thickness dependent activity of nanostructured TiO 2/α-Fe 2O 3 photocatalyst thin films

    Science.gov (United States)

    Akhavan, O.

    2010-12-01

    The effect of thickness of TiO 2 coating on synergistic photocatalytic activity of TiO 2 (anatase)/α-Fe 2O 3/glass thin films as photocatalysts for degradation of Escherichia coli bacteria in a low-concentration H 2O 2 solution and under visible light irradiation was investigated. Nanograined α-Fe 2O 3 films with optical band-gap of 2.06 eV were fabricated by post-annealing of thermal evaporated iron oxide thin films at 400 °C in air. Increase in thickness of the Fe 2O 3 thin film (here, up to 200 nm) resulted in a slight reduction of the optical band-gap energy and an increase in the photoinactivation of the bacteria. Sol-gel TiO 2 coatings were deposited on the α-Fe 2O 3 (200 nm)/glass films, and then, they were annealed at 400 °C in air for crystallization of the TiO 2 and formation of TiO 2/Fe 2O 3 heterojunction. For the TiO 2 coatings with thicknesses ≤50 nm, the antibacterial activity of the TiO 2/α-Fe 2O 3 (200 nm) was found to be better than the activity of the bare α-Fe 2O 3 film. The optimum thickness of the TiO 2 coating was found to be 10 nm, resulting in about 70 and 250% improvement in visible light photo-induced antibacterial activity of the TiO 2/α-Fe 2O 3 thin film as compared to the corresponding activity of the bare α-Fe 2O 3 and TiO 2 thin films, respectively. The improvement in the photoinactivation of bacteria on surface of TiO 2/α-Fe 2O 3 was assigned to formation of Ti-O-Fe bond at the interface.

  5. Nanostructured TiO2 films for dye-sensitized solar cells prepared by the sol-gel method.

    Science.gov (United States)

    Jin, Young Sam; Kim, Kyung Hwan; Park, Sang Joon; Yoon, Hyon Hee; Choi, Hyung Wook

    2011-12-01

    TiO2 films were prepared on glass substrates using the sol-gel process for a dye-sensitized solar cell application. The TiO2 sol was prepared using hydrolysis/polycondensation. Titanium (IV) Tetra Isopropoxide (TTIP) was used as precursor and Nitric acid (HNO3) was used as a catalyst for the peptization. The crystal structure and morphology of the prepared materials were characterized by XRD, and an SEM. The observations confirmed the nanocrystalline nature of the TiO2. The reaction parameters, such as the catalyst concentrations, the calcination time, and the calcination temperature were varied during the synthesis in order to achieve nanosize TiO2 particles. The prepared TiO2 particles were coated onto FTO glass using a screen printing technique. The prepared TiO2 films were characterized by UV-vis. The TiO2 particles calcinated at low temperatures showed an anatase phase they grew into a rutile phase when the calcination temperature increased. The size and structure of the TiO2 particles were adjusted to specific surface areas. It was found that the conversion efficiency of the DSSC was highly affected by the properties of the TiO2 particles.

  6. Interaction of Sensitizing Dyes with Nanostructured TiO2 Film in Dye-Sensitized Solar Cells Using Terahertz Spectroscopy

    Science.gov (United States)

    Ghann, William; Rahman, Aunik; Rahman, Anis; Uddin, Jamal

    2016-07-01

    The objective of this investigation was to shed light on the nature of interaction of different organic dyes and an inorganic dye, Ruthenium (II) polypyridine complex, with TiO2 nanoparticles. TiO2 is commonly deployed as an efficient energy transfer electrode in dye sensitized solar cells. The efficiency of dye sensitized solar cells is a function of the interaction of a dye with the electrode material such as TiO2. To the best of our knowledge the present study is the first effort in the determination of terahertz absorbance signals, investigation of real-time dye permeation kinetics, and the surface profiling and 3D imaging of dye sensitized TiO2 films. Herein, we report that the terahertz spectra of the natural dye sensitized TiO2 films were distinctively different from that of the inorganic dye with prominent absorption of natural dyes occurring at approximately the same wavelength. It was observed that the permeation of the natural dyes were more uniform through the layers of the mesoporous TiO2 compared to the inorganic dye. Finally, defects and flaws on TiO2 film were easily recognized via surface profiling and 3D imaging of the films. The findings thus offer a new approach in characterization of dye sensitized solar cells.

  7. Interaction of Sensitizing Dyes with Nanostructured TiO2 Film in Dye-Sensitized Solar Cells Using Terahertz Spectroscopy.

    Science.gov (United States)

    Ghann, William; Rahman, Aunik; Rahman, Anis; Uddin, Jamal

    2016-07-22

    The objective of this investigation was to shed light on the nature of interaction of different organic dyes and an inorganic dye, Ruthenium (II) polypyridine complex, with TiO2 nanoparticles. TiO2 is commonly deployed as an efficient energy transfer electrode in dye sensitized solar cells. The efficiency of dye sensitized solar cells is a function of the interaction of a dye with the electrode material such as TiO2. To the best of our knowledge the present study is the first effort in the determination of terahertz absorbance signals, investigation of real-time dye permeation kinetics, and the surface profiling and 3D imaging of dye sensitized TiO2 films. Herein, we report that the terahertz spectra of the natural dye sensitized TiO2 films were distinctively different from that of the inorganic dye with prominent absorption of natural dyes occurring at approximately the same wavelength. It was observed that the permeation of the natural dyes were more uniform through the layers of the mesoporous TiO2 compared to the inorganic dye. Finally, defects and flaws on TiO2 film were easily recognized via surface profiling and 3D imaging of the films. The findings thus offer a new approach in characterization of dye sensitized solar cells.

  8. Nanostructured Er3+-doped SiO2-TiO2 and SiO2-TiO2-Al2O3 sol-gel thin films for integrated optics

    Science.gov (United States)

    Predoana, Luminita; Preda, Silviu; Anastasescu, Mihai; Stoica, Mihai; Voicescu, Mariana; Munteanu, Cornel; Tomescu, Roxana; Cristea, Dana

    2015-08-01

    The nanostructured multilayer silica-titania or silica-titania-alumina films doped with Er3+ were prepared by sol-gel method. The sol-gel method is a flexible and convenient way to prepare oxide films on several types of substrates, and for this reason it was extensively investigated for optical waveguides fabrication. The selected molar composition was 90%SiO2-10%TiO2 or 85%SiO2-10%TiO2-5% Al2O3 and 0.5% Er2O3. The films were characterized by Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), Spectroellipsometry (SE), as well as by Atomic Force Microscopy (AFM) and photoluminescence (PL). The films deposited on Si/SiO2 substrate by dip-coating or spin-coating, followed by annealing at 900 °C, presented homogenous and continuous surface and good adherence to the substrate. Differences were noticed in the structure and properties of the prepared films, depending on the composition and the number of deposited layers. Channel optical waveguides were obtained by patterning Er3+-doped SiO2-TiO2 and SiO2-TiO2-Al2O3 sol-gel layers deposited on oxidized silicon wafers.

  9. Anti-fogging nanofibrous SiO(2) and nanostructured SiO(2)-TiO(2) films made by rapid flame deposition and in situ annealing.

    Science.gov (United States)

    Tricoli, Antonio; Righettoni, Marco; Pratsinis, Sotiris E

    2009-11-03

    Transparent, pure SiO(2), TiO(2), and mixed silica-titania films were (stochastically) deposited directly onto glass substrates by flame spray pyrolysis of organometallic solutions (hexamethyldisiloxane or tetraethyl orthosilicate and/or titanium tetra isopropoxide in xylene) and stabilized by in situ flame annealing. Silicon dioxide films consisted of a network of interwoven nanofibers or nanowires several hundred nm long and 10-15 nm thick, as determined by microscopy. These nanowire or nanofibrous films were formed by chemical vapor deposition (surface growth) on bare glass substrates during scalable combustion of precursor solutions at ambient conditions, for the first time to our knowledge, as determined by thermophoretic sampling of the flame aerosol and microscopy. In contrast, titanium dioxide films consisted of nanoparticles 3-5 nm in diameter that were formed in the flame and deposited onto the glass substrate, resulting in highly porous, lace-like nanostructures. Mixed SiO(2)-TiO(2) films (40 mol % SiO(2)) had similar morphology to pure TiO(2) films. Under normal solar radiation, all such films having a minimal thickness of about 300 nm completely prevented fogging of the glass substrates. These anti-fogging properties were attributed to inhibition of water droplet formation by such super-hydrophilic coatings as determined by wetting angle measurements. Deactivated (without UV radiation) pure TiO(2) coatings lost their super-hydrophilicity and anti-fogging properties even though their wetting angle was reduced by their nanowicking. In contrast, SiO(2)-TiO(2) coatings exhibited the best anti-fogging performance at all conditions taking advantage of the high surface coverage by TiO(2) nanoparticles and the super-hydrophilic properties of SiO(2) on their surface.

  10. Investigation of optical, structural and morphological properties of nanostructured boron doped TiO2 thin films

    Indian Academy of Sciences (India)

    Savaş Sönmezoǧlu; Banu Erdoǧan; İskender Askeroǧlu

    2013-12-01

    Pure and different ratios (1, 3, 5, 7 and 10%) of boron doped TiO2 thin films were grown on the glass substrate by using sol–gel dip coating method having some benefits such as basic and easy applicability compared to other thin film production methods. To investigate the effect of boron doped on the physical properties of TiO2, structural, morphological and optical properties of growth thin films were examined. 1% boron-doping has no effect on optical properties of TiO2 thin film; however, optical properties vary with > 1%. From X-ray diffraction spectra, it is seen that TiO2 thin films together with doping of boron were formed along with TiB2 hexagonal structure having (111) orientation, B2O3 cubic structure having (310) orientation, TiB0.024O2 tetragonal structure having rutile phase (110) orientation and polycrystalline structures. From SEM images, it is seen that particles together with doping of boron have homogeneously distributed and held onto surface.

  11. 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.

  12. 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.

  13. Optical parameters induced by phase transformation in RF magnetron sputtered TiO2 nanostructured thin films

    Directory of Open Access Journals (Sweden)

    Prabitha B. Nair

    2014-06-01

    Full Text Available Pure TiO2 thin films were deposited onto quartz substrates using a ceramic TiO2 target at an elevated substrate temperature of 573 K by RF magnetron sputtering, and an analysis of structural, optical and photoluminescence characteristics of the films upon phase transformation is reported in this paper. Structural investigations using X-ray diffraction revealed that the as-deposited film was amorphous in nature. Thermal annealing for 2 h at 873 K in air resulted in the formation of anatase phase, and a phase transformation to rutile was observed at 1073 K. An increase in grain size and an improvement in crystallinity were also observed on annealing. Rod- like rutile crystallites were observed in the SEM images of the film annealed at 1273 K. As-deposited films and films annealed up to 1073 K were highly transparent in the visible region with a transparency >80%. Optical band gap of the films decreased upon thermal annealing which is attributed to phase transformation from amorphous to anatase and then to rutile. Optical parameters such as refractive index, optical conductivity and optical dielectric constant increased with increase in annealing temperature. Since rutile is the optically active phase, the superior refractive index of the film annealed at 1073 K along with its high transparency in visible region suggests the application of this film in antireflective coatings. Photoluminescence emission of maximum intensity was observed for the film annealed at 873 K, which exhibits anatase phase. Intense blue emission observed in this film makes it suitable for use in optoelectronic display devices.

  14. Optical parameters induced by phase transformation in RF magnetron sputtered TiO2 nanostructured thin films

    Institute of Scientific and Technical Information of China (English)

    Prabitha B.Nair; V.B.Justinvictor; Georgi P.Daniel; K.Joy; K.C.James Raju; David Devraj Kumar; P.V.Thomas

    2014-01-01

    Pure TiO2 thin films were deposited onto quartz substrates using a ceramic TiO2 target at an elevated substrate temperature of 573 K by RF magnetron sputtering, and an analysis of structural, optical and photoluminescence characteristics of the films upon phase transformation is reported in this paper. Structural investigations using X-ray diffraction revealed that the as-deposited film was amorphous in nature. Thermal annealing for 2 h at 873 K in air resulted in the formation of anatase phase, and a phase transformation to rutile was observed at 1073 K. An increase in grain size and an improvement in crystallinity were also observed on annealing. Rod-like rutile crystallites were observed in the SEM images of the film annealed at 1273 K. As-deposited films and films annealed up to 1073 K were highly transparent in the visible region with a transparency 4 80%. Optical band gap of the films decreased upon thermal annealing which is attributed to phase transformation from amorphous to anatase and then to rutile. Optical parameters such as refractive index, optical conductivity and optical dielectric constant increased with increase in annealing temperature. Since rutile is the optically active phase, the superior refractive index of the film annealed at 1073 K along with its high transparency in visible region suggests the application of this film in antireflective coatings. Photoluminescence emission of maximum intensity was observed for the film annealed at 873 K, which exhibits anatase phase. Intense blue emission observed in this film makes it suitable for use in optoelectronic display devices.

  15. Influence of nanostructured TiO2 film thickness on photoelectrode structure and performance of flexible Dye- Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    M. Malekshahi Byranvand

    2012-09-01

    Full Text Available A  commercial  Ti-Nanoxide  was  deposited  on  In-doped  SnO2 (ITO polymer  substrates by  tape casting  technique with different thicknesses  (7,  14  and  36μm  to  be  used  as  photoelectrode  in flexible  dye-sensitized  solar  cells  (DSSCs.  Ruthenium  dye  was adsorbed on each TiO2 film for 24 h. The resulting photoelectrodes were used to form flexible DSSCs in combination with electrolyte and  counter  electrode.  The  prepared  films  were  characterized  by scanning electron microscopy (SEM and atomic force microscopy (AFM.    Photovoltaic  parameters  like  short  circuit  current  (Isc, open  circuit  voltage  (Voc,  fill  factor  (FF  and power  conversion efficiency (η were evaluated for fabricated cells. The cell formed with a TiO2 film of 14μm thickness reached the best performance. 2012 JNS All rights reserved

  16. Nanostructure of silver metal produced photocatalytically in TiO2 films and the mechanism of the resulting photochromic behavior.

    Science.gov (United States)

    Kelly, K Lance; Yamashita, Koichi

    2006-04-20

    The optical activity of composite films created by the photocatalytic reduction of silver or gold ions in TiO(2) upon irradiation by UV light has up to now been discussed in terms of the formation and light-induced destruction of distinct nanoparticles molded inside the porous nanocrystalline film. We present results from classical light scattering calculations and a logical analysis of experimental observations to add detail to the mechanism. As opposed to large, solid metal nanoparticles, coatings and small particles in heterogeneous external dielectric environments account for observations such as the broad optical spectrum and multiwavelength photochromic responses. For some steps of the photochromic process, we propose that visible light permits an equilibrium promoting the growth of small metal features or suspended particles. We use a new expression for the restricted path length in our size-dependent broadening corrections of metal shells and discuss this briefly. We conclude by discussing the consequence of plasmon absorption in the proximity of the electronically active TiO(2) surrounding matrix, leading to mass transfer and shape change of the metal and photochromic properties of the film.

  17. Semi-transparent ordered TiO2 nanostructures prepared by anodization of titanium thin films deposited onto the FTO substrate

    Science.gov (United States)

    Szkoda, Mariusz; Lisowska-Oleksiak, Anna; Grochowska, Katarzyna; Skowroński, Łukasz; Karczewski, Jakub; Siuzdak, Katarzyna

    2016-09-01

    In a significant amount of cases, the highly ordered TiO2 nanotube arrays grow through anodic oxidation of a titanium metal plate immersed in electrolyte containing fluoride ions. However, for some practical applications, e.g. solar cells or electrochromic windows, the semi-transparent TiO2 formed directly on the transparent, conductive substrate is very much desired. This work shows that high-quality Ti coating could be formed at room temperature using an industrial magnetron sputtering system within 50 min. Under optimized conditions, the anodization process was performed on 2 μm titanium films deposited onto the FTO (fluorine-tin-oxide) support. Depending on the electrolyte type, highly ordered tubular or porous titania layers were obtained. The fabricated samples, after their thermal annealing, were investigated using scanning electron microscopy, Raman spectroscopy and UV-vis spectroscopy in order to investigate their morphology, crystallinity and absorbance ability. The photocurrent response curves indicate that materials are resistant to the photocorrosion process and their activity is strongly connected to optical properties. The most transparent TiO2 films were fabricated when Ti was anodized in water electrolyte, whereas the highest photocurrent densities (12 μA cm-2) were registered for titania received after Ti anodization in ethylene glycol solution. The obtained results are of significant importance in the production of thin, semi-transparent titania nanostructures on a commercial scale.

  18. Electrochemical deposition of nano-structured ZnO on the nanocrystalline TiO2 film and its characterization

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    One-dimensional structure of ZnO nanorod arrays on nanocrystalline TiO2/ITO conductive glass substrates has been fabricated by cathodic reduction electrochemical deposition methods in the three-electrode system,with zinc nitrate aqueous solution as the electrolyte,and were characterized by X-ray diffraction (XRD),scanning electron microscopy (SEM),energy-dispersive X-ray (EDX) and photoluminescence (PL) spectra.The effects of film substrates,electrolyte concentration,deposition time,and methenamine (HMT) addition on ZnO deposition and its luminescent property were investigated in detail.The results show that,compared with on the ITO glass substrate,ZnO is much easily achieved by electrochemical deposition on the TiO2 nanoparticle thin films.ZnO is hexagonally structured wurtzite with the c-axis preferred growth,and further forms nanorod arrays vertically on the substrates.It is favorable to the growth of ZnO to extend the deposition time,to increase the electrolyte concentration,and to add a certain amount of HMT in the system,consequently improving the crystallinity and orientation of ZnO arrays.It is demonstrated that the obtained ZnO arrays with high crystallinity and good orientation display strong band-edge UV (375 nm) and weak surface-state-related green (520 nm) emission peaks.

  19. Influence of TiO2 nanostructures on the optical absorption of organic-inorganic perovskite

    Science.gov (United States)

    Liu, Zongyi; Ye, Mao; Ostrowski, Michel; Yi, Ya Sha

    2016-04-01

    This work aims to reveal the strong influence of TiO2 nanostructures on the light absorption property of TiO2 and perovskite mixture. Three TiO2 nanostructures, i.e., nanoparticles (S1), ultrapure nanorods (S2), and ultrasmall nanorods (S3), were studied: S1 was selected as a baseline; S2 and S3 were synthesized from S1 by using modified hydrothermal processes. Mesoporous TiO2 thin films were spin-coated from solutions containing these TiO2 nanorods and nanoparticles (S1 as baseline). Organic-inorganic hybrid perovskite CH3NH3PbI3 was then incorporated into these mesoporous TiO2 thin films. Optical absorption results showed that the perovskite mixture with ultrasmall TiO2 nanostructures (S3) has significantly higher optical absorption coefficient. Finite-difference time domain models were built based on three distinct nanostructures of TiO2 and CH3NH3PbI3 mixtures fabricated (S1 to S3) to understand their optical absorption properties. Our work is promising to fabricate TiO2 nanostructures, as a backbone structure, for a series of applications including photovoltaics and photodetection.

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

    Directory of Open Access Journals (Sweden)

    Daniel Grando Stroppa

    2008-01-01

    Full Text Available 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 morphology 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.

  1. Preparation of nanostructured Bi-modified TiO2 thin films by crossed-beam laser ablation plasmas

    Science.gov (United States)

    Escobar-Alarcon, L.; Solís-Casados, D. A.; González-Zavala, F.; Romero, S.; Fernandez, M.; Haro-Poniatowski, E.

    2017-01-01

    The preparation and characterization of titanium dioxide thin films modified with different amounts of bismuth using a two laser ablation plasmas configuration is reported. The plasmas were produced ablating simultaneously two different targets, one of bismuth and other of titanium dioxide, using a Nd:YAG laser with emission in the fundamental line. The elemental composition, together with the vibrational and optical properties of the deposited films were investigated as a function of the parameters of the bismuth plasma. The composition of the thin films was determined from measurements of X-ray photoelectron spectroscopy (XPS) as well as by Rutherford backscattering spectroscopy (RBS). The structural modification of the deposited material, due to the incorporation of Bi, was characterized by Raman spectroscopy. The optical properties were determined from UV-Vis spectroscopy measurements. It is found that bismuth incorporation has an important effect on the optical properties of TiO2 narrowing the band gap from 3.2 to 2.5 eV.

  2. TiO2 thin film photocatalyst

    Institute of Scientific and Technical Information of China (English)

    YU Jiaguo

    2004-01-01

    It is well known that the photocatalytic activity of TiO2 thin films strongly depends on the preparing methods and post-treatment conditions, since they have a decisive influence on the chemical and physical properties of TiO2 thin films.Therefore, it is necessary to elucidate the influence of the preparation process and post-treatment conditions on the photocatalytic activity and surface microstructures of the films. This review deals with the preparation of TiO2 thin film photocatalysts by wet-chemical methods (such as sol-gel, reverse micellar and liquid phase deposition) and the comparison of various preparation methods as well as their advantage and disadvantage. Furthermore, it is discussed that the advancement of photocatalytic activity, super-hydrophilicity and bactericidal activity of TiO2 thin film photocatalyst in recent years.

  3. Formation of rod-like nanostructure by aggregation of TiO2 nanoparticles with improved performances

    Indian Academy of Sciences (India)

    Weijuan Zhang; Wenkai Chang; Baozhen Cheng; Zenghe Li; Junhui Ji; Yang Zhao; Jun Nie

    2015-10-01

    To improve the performance of titanium dioxide (TiO2)-based devices, many efforts have been made to prepare nanostructures with composite of TiO2 nanoparticles and nanorods. In this work, a novel rod-like TiO2 nanostructure was obtained via a controllable hydrolysis process. Morphology and structure analysis showed that the rod-like nanostructure was a well-aligned aggregate of nearly spherical TiO2 nanoparticles. Rod-like TiO2 nanoparticle aggregates were fabricated on a primary TiO2 nanoparticle-based layer without the use of template, and formed a hierarchical TiO2 composite film together. The photocatalytic activity of the TiO2 film with rod-like nanoparticle aggregates was evaluated by the degradation of methylene blue. The antibacterial activity of fabricated hierarchical TiO2 film was assessed against Staphylococcus aureus. The photoelectrochemical property of this film as the photoanode in assemble dye-sensitized solar cell was also tested. Compared with randomly distributed nanoparticle-based TiO2 film, the hierarchical TiO2 film exhibited improved performance of photocatalysis, antibacterial activity and photoelectric conversion.

  4. One-Dimensional Nanostructured TiO2 for Photocatalytic Degradation of Organic Pollutants in Wastewater

    Directory of Open Access Journals (Sweden)

    Ting Feng

    2014-01-01

    Full Text Available The present paper reviews the progress in the synthesis of one-dimensional (1D TiO2 nanostructures and their environmental applications in the removal of organic pollutants. According to the shape, 1D TiO2 nanostructures can be divided into nanorods, nanotubes, nanowires/nanofibers, and nanobelts. Each of them can be synthesized via different technologies, such as sol-gel template method, chemical vapor deposition, and hydrothermal method. These methods are discussed in this paper, and the recent development of the synthesis technologies is also presented. Furthermore, the organic pollutants, degradation using the synthesized 1D TiO2 nanostructures is studied as an important application of photocatalytic oxidation (PCO. The 1D nanostructured TiO2 exhibited excellent photocatalytic activity in a PCO process, and the mechanism of photocatalytic degradation of organic pollutants is also discussed. Moreover, the modification of 1D TiO2 nanostructures using metal ions, metal oxide, or inorganic element can further enhance the photocatalytic activity of the photocatalyst. This phenomenon can be explained by the suppression of e−-h+ pairs recombination rate, increased specific surface area, and reduction of band gap. In addition, 1D nanostructured TiO2 can be further constructed as a film or membrane, which may extend its practical applications.

  5. Lithium insertion in nanostructured TiO(2)(B) architectures.

    Science.gov (United States)

    Dylla, Anthony G; Henkelman, Graeme; Stevenson, Keith J

    2013-05-21

    Electric vehicles and grid storage devices have potentialto become feasible alternatives to current technology, but only if scientists can develop energy storage materials that offer high capacity and high rate capabilities. Chemists have studied anatase, rutile, brookite and TiO2(B) (bronze) in both bulk and nanostructured forms as potential Li-ion battery anodes. In most cases, the specific capacity and rate of lithiation and delithiation increases as the materials are nanostructured. Scientists have explained these enhancements in terms of higher surface areas, shorter Li(+) diffusion paths and different surface energies for nanostructured materials allowing for more facile lithiation and delithiation. Of the most studied polymorphs, nanostructured TiO2(B) has the highest capacity with promising high rate capabilities. TiO2(B) is able to accommodate 1 Li(+) per Ti, giving a capacity of 335 mAh/g for nanotubular and nanoparticulate TiO2(B). The TiO2(B) polymorph, discovered in 1980 by Marchand and co-workers, has been the focus of many recent studies regarding high power and high capacity anode materials with potential applications for electric vehicles and grid storage. This is due to the material's stability over multiple cycles, safer lithiation potential relative to graphite, reasonable capacity, high rate capability, nontoxicity, and low cost (Bruce, P. G.; Scrosati, B.; Tarascon, J.-M. Nanomaterials for Rechargeable Lithium Batteries. Angew. Chem., Int. Ed.2008, 47, 2930-2946). One of the most interesting properties of TiO2(B) is that both bulk and nanostructured forms lithiate and delithiate through a surface redox or pseudocapacitive charging mechanism, giving rise to stable high rate charge/discharge capabilities in the case of nanostructured TiO2(B). When other polymorphs of TiO2 are nanostructured, they still mainly intercalate lithium through a bulk diffusion-controlled mechanism. TiO2(B) has a unique open crystal structure and low energy Li

  6. 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 ΔhRF∼ 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 (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.

  7. TiO2-coated nanostructures for dye photo-degradation in water.

    Science.gov (United States)

    Scuderi, Viviana; Impellizzeri, Giuliana; Romano, Lucia; Scuderi, Mario; Nicotra, Giuseppe; Bergum, Kristin; Irrera, Alessia; Svensson, Bengt G; Privitera, Vittorio

    2014-01-01

    The photocatalytic efficiency of a thin-film TiO2-coated nanostructured template is studied by dye degradation in water. The nanostructured template was synthesized by metal-assisted wet etching of Si and used as substrate for the deposition of a thin film of TiO2 (10 nm thick) by atomic layer deposition. A complete structural characterization was made by scanning and transmission electron microscopies. The significant photocatalytic performance was evaluated by the degradation of two dyes in water: methylene blue and methyl orange. The relevance of the reported results is discussed, opening the route toward the application of the synthesized nanostructured TiO2 for water purification.

  8. Effect of crystal structure on photoinduced superhydrophilicity of copper grafted TiO2 nanostructure thin film

    Indian Academy of Sciences (India)

    Akbar Eshaghi; Ameneh Eshaghi

    2013-02-01

    In this work, copper grafted titanium dioxide (rutile and brookite) thin films were deposited on glass substrates using the dip-coatingmethod. Field emission scanning electron microscopy and X-ray photoelectron spectroscopy were used to evaluate the surface morphology and properties of the film surfaces. The water contact angle on the film surfaces during irradiation and storage in a dark place was measured by a contact angle analyser. The results indicate that copper grafted titanium dioxide brookite thin film showed higher hydrophilicity than copper grafted titania rutile thin film.

  9. Synthesis, characterizations and applications of some nanomaterials (TiO2 and SiC nanostructured films, organized CNT structures, ZnO structures and CNT{blood platelet clusters)

    Indian Academy of Sciences (India)

    O N Srivastava; A Srivastava; D Dash; D P Singh; R M Yadava; P R Mishra; J Singh

    2005-10-01

    TiO2 nanostructured films have been synthesized by the hydrolysis of Ti[OCH(CH3)2]4 as the precursor. These films have been utilized for the dissociation of phenol contaminant in water. Free-standing nanostructured film of silicon carbide (SiC) has been synthesized, employing a simple and new route of spray pyrolysis technique utilizing a slurry of Si in hexane. Another study is done on organized carbon nanotube (CNT) structures. These are made in the form of hollow cylinders (50 mm length, 4 mm diameter and 1.5 mm wall thickness). These CNT-based cylinders are made of conventional CNT and bamboo-shaped CNT. The filtrations of heavy hydrocarbons and . coli bacteria from water have been carried out. In addition to this, ZnO nanostructures have also been studied. Another study concerns CNT-blood platelet clusters.

  10. Nanostructured TiO2-based gas sensors with enhanced sensitivity to reducing gases

    Directory of Open Access Journals (Sweden)

    Wojciech Maziarz

    2016-11-01

    Full Text Available 2D TiO2 thin films and 3D flower-like TiO2-based nanostructures, also decorated with SnO2, were prepared by chemical and thermal oxidation of Ti substrates, respectively. The crystal structure, morphology and gas sensing properties of the TiO2-based sensing materials were investigated. 2D TiO2 thin films crystallized mainly in the form of rutile, while the flower-like 3D nanostructures as anatase. The sensor based on the 2D TiO2 showed the best performance for H2 detection, while the flower-like 3D nanostructures exhibited enhanced selectivity to CO(CH32 after sensitization by SnO2 nanoparticles. The sensor response time was of the order of several seconds. Their fast response, high sensitivity to selected gas species, improved selectivity and stability suggest that the SnO2-decorated flower-like 3D nanostructures are a promising material for application as an acetone sensor.

  11. Deliberate Design of TiO2 Nanostructures towards Superior Photovoltaic Cells.

    Science.gov (United States)

    Sun, Ziqi; Liao, Ting; Sheng, Liyuan; Kou, Liangzhi; Kim, Jung Ho; Dou, Shi Xue

    2016-08-01

    TiO2 nanostructures are being sought after as flexibly utilizable building blocks for the fabrication of the mesoporous thin-film photoelectrodes that are the heart of the third-generation photovoltaic devices, such as dye-sensitized solar cells (DSSCs), quantum-dot-sensitized solar cells (QDSSCs), and the recently promoted perovskite-type solar cells. Here, we report deliberate tailoring of TiO2 nanostructures for superior photovoltaic cells. Morphology engineering of TiO2 nanostructures is realized by designing synthetic protocols in which the precursor hydrolysis, crystal growth, and oligomer self-organization are precisely controlled. TiO2 nanostructures in forms varying from isolated nanocubes, nanorods, and cross-linked nanorods to complex hierarchical structures and shape-defined mesoporous micro-/nanostructures were successfully synthesized. The photoanodes made from the shape-defined mesoporous TiO2 microspheres and nanospindles presented superior performances, owing to the well-defined overall shapes and the inner ordered nanochannels, which allow not only a high amount of dye uptake, but also improved visible-light absorption. This study provides a new way to seek an optimal synthetic protocol to meet the required functionality of the nanomaterials.

  12. Photoinduced properties of nanocrystalline TiO2 sol–gel derived thin films

    Indian Academy of Sciences (India)

    Akbar Eshaghi; Mahmoud Pakshir; Reza Mozaffarinia

    2010-08-01

    In this paper, nanostructure TiO2 thin films were deposited on glass substrates by sol–gel dip coating technique. X-ray diffraction and Fourier transform infrared spectroscopy were used to determine film behaviour. The super-hydrophilicity was assessed by contact angle measurement. Photocatalytic properties of these films were evaluated by degradation of methylene blue under UV irradiation. The XRD pattern of TiO2 powder samples confirmed the presence of polycrystalline anatase phase with a crystal size of 17 nm. The results indicated that UV light irradiation had significant effect on super-hydrophilic and photocatalytic properties of TiO2 thin films.

  13. Photocatalytic TiO2/glass nanoflake array films.

    Science.gov (United States)

    Ho, Wingkei; Yu, Jimmy C; Yu, Jiaguo

    2005-04-12

    A new approach for the fabrication of oriented TiO2/glass nanoflake arrays has been developed. The ceramic nanoflake array was formed on a glass substrate via a simple, low temperature, and one-step hydrothermally induced phase separation approach without using any templates or additives. The factors affecting the formation of ceramic nanoflakes were examined by various characterization techniques. The results showed that the leaching of the soluble phase from the glass surface through hydrothermal processes resulted in oriented uniform ceramic nanoflake arrays. Electron microscope observations revealed that the nanoflakes formed a continuous porous three-dimensional-network array with a large surface-to-volume ratio. In addition, an anatase TiO2 film was successfully coated onto the nanoflake array by the sol-gel method. The TiO2/glass nanoflake array exhibited high activity for the photocatalytic degradation of acetone and for photoinduced hydrophilic conversion. Such enhancements were attributed to the beneficial effects of the new continuous porous three-dimensional-interconnected nanoflake network and its surface geometrical nanostructure. The present approach provides a convenient route to modify a photocatalytic coating with a porous nano-architectured substrate. This opens extensive new opportunities in the design of semiconductor/ceramic nanostructural array thin films with unusual properties for future optical and electronic applications.

  14. Influence of catalyst on structural and morphological properties of TiO2 nanostructured films prepared by sol-gel on glass

    Institute of Scientific and Technical Information of China (English)

    Mehdi Alzamani; Ali Shokuhfar; Ebrahim Eghdam; Sadegh Mastali

    2013-01-01

    Transparent TiO2 thin films have been prepared by the sol-gel method using titanium alkoxides as precursors. Thin films were deposited on glass supports by the dip-coating technique. The TiO2 layer acts as a self-cleaning coating generated from its photocatalysis and photoinduced superhydrophilicity. The crystalline structure of TiO2 films was dominantly identified as the anatase phase, consisted of uniform spherical particles of about 14-50 nm in size, which strongly depends upon catalyst-type and heat treatment temperature. Increasing heat treating temperature can lead to an increase in crystalline size. The results indicated that the sample S.S (sample derived from sol containing sulfuric acid as catalyst) exhibits superhydrophilic nature and better photocatalytic activity, which can be attributed to its higher anatase content and lower crystalline size. Morphological studies, carried out using Atomic Force Microscopy (AFM), confirm the presence of crystalline phase with such a grain size and low surface roughness. Thus, the applied films exhibiting high photocatalytic activity, superhydrophilic behavior, and low surface roughness can be used as an efficient self-cleaning coating on glass and other optical applications.

  15. Comparison of photocatalytic properties of TiO2 thin films and fibers

    Science.gov (United States)

    Ozdemir, Mehtap; Kurt, Metin; Ozyuzer, Lutfi; Aygun, Gulnur

    2016-10-01

    Efficiency of solar panels degrades as a result of organic contamination such as airborne particles, bird droppings and leaves. Any foreign object on photovoltaic panels reduces the sunlight entering the absorbing surface of the solar panels. Since this leads to a major problem decreasing in energy production, solar panels should be cleaned. The self-cleaning method can be preferred. There are some methods to clean the surface of solar panels. Among the self-cleaning materials, TiO2 is the most preferable ones because of its powerful photocatalytic properties. In this study, photocatalytic TiO2 were produced in two different nanostructures: nanofibers and thin films. TiO2 nanofibers were successfully produced by electrospinning. TiO2 thin films were fabricated by reactive magnetron sputtering technique. Both TiO2 nanofiber and thin film structures were heat-treated to form TiO2 in anatase phase at 600 °C for 2 h in air. Then, they were evaluated by SEM analyses for morphology, X-ray diffraction (XRD) analyses for phase structures, X-ray photoelectron spectroscopy (XPS) for the chemical state and atomic concentration, and UV-spectrometer for photocatalytic performance. The results indicate that photocatalytic and transmittance properties of TiO2 thin films are better than those of nanofibers. Consequently, TiO2 based thin films exhibit better performance for solar cell applications due to the surface cleanliness.

  16. Layered TiO2: PVK nano-composite thin films for photovoltaic applications. TiO2: PVK nano-composite thin films.

    Science.gov (United States)

    Kaune, G; Wang, W; Metwalli, E; Ruderer, M; Rossner, R; Roth, S V; Müller-Buschbaum, P

    2008-01-01

    The influence of the solvent used for spin-coating on the homogeneity of poly(N-vinylcarbazole) (PVK) films is investigated. Homogenous films are obtained only by the use of toluene, solution in tetrahydrofuran (THF) and chloroform results in radially oriented inhomogeneities and films prepared by use of N-methylpyrrolidone and dimethylacetamide show particle formation during spin-coating. Layered nano-composite thin films are prepared by spin-coating a PVK film on top of a nano-structured titanium dioxide ( TiO2) layer. The TiO2 thin films are prepared by a sol-gel process using an amphiphilic copolymer as structure-directing agent. Structural characterisation of the TiO2 :PVK nano-composite films is done by field emission scanning electron microscopy (FESEM) and grazing-incidence small-angle scattering (GISAXS). Bare TiO2 films are probed for comparison. Light is basically only absorbed in the ultraviolet regime and absorption slightly increases upon addition of PVK, which makes the layered TiO2 :PVK nano-composite thin films good candidates for UV photovoltaic devices. Furthermore, absorption remains stable over a period of several days.

  17. Composite WO3/TiO2 nanostructures for high electrochromic activity.

    Energy Technology Data Exchange (ETDEWEB)

    Reyes, Karla Rosa; Stephens, Zachary Dan.; Robinson, David B.

    2013-05-01

    A composite material consisting of TiO2 nanotubes (NTs) with WO3 electrodeposited homogeneously on its surface has been fabricated, detached from its substrate, and attached to a fluorine-doped tin oxide film on glass for application to electrochromic (EC) reactions. A paste of TiO2 made from commercially available TiO2 nanoparticles creates an interface for the TiO2 NT film to attach to the FTO glass, which is conductive and does not cause solution-phase ions in an electrolyte to bind irreversibly with the material. The effect of NT length on the current density and the EC contrast of the material were studied. The EC redox reaction seen in this material is diffusion- limited, having relatively fast reaction rates at the electrode surface. The composite WO3/TiO2 nanostructures showed higher ion storage capacity, better stability, enhanced EC contrast and longer memory time compared with the pure WO3 and TiO2.

  18. Nanostructured ZnO, TiO2, and Composite ZnO/TiO2 Films for Application in Dye-Sensitized Solar Cells

    OpenAIRE

    Myrsini Giannouli

    2013-01-01

    The effects of using composite semiconductor films on the efficiency and stability of dye-sensitized solar cells (DSSCs) were investigated. Four different types of composite ZnO/TiO2 cells were developed and sensitized with the organic molecules Coumarin 343 (C343) and Rose Bengal (RB). A comparative assessment of the different composite cells was conducted, and the photovoltaic performance of single-semiconductor ZnO and TiO2 solar cells was also compared to that of the composite ZnO/TiO2 ce...

  19. SnO2/TiO2 bilayer thin films exhibiting superhydrophilic properties

    Science.gov (United States)

    Talinungsang, Nibedita Paul; Purkayastha, Debarun Dhar

    2017-05-01

    Nanostructured thin films of TiO2, SnO2, and SnO2/TiO2 have been deposited by sol-gel method. The films are characterized by X-ray diffraction, wettability and optical properties. In the present work, we have achieved a way of converting hydrophilic to super-hydrophilic state by incorporating TiO2 buffer layer in between substrate and SnO2 film, which has its utility in anti-fogging surfaces. The decrease in contact angle of water over SnO2/TiO2 bilayer is attributed to the increase in roughness of the film as well as surface energy of the substrate.

  20. Electrospun polystyrene fibres on TiO$_2$ nanostructured film to enhance the hydrophobicity and corrosion resistance of stainless steel substrates

    Indian Academy of Sciences (India)

    Azimirad R; Safa S

    2016-03-01

    A dual layer of dip-coated TiO$_2$ film (top layer) and electrospun polystyrene (bottom layer) was coated on stainless steel (SS) substrates. The morphological and structural studies were performed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Their hydrophobicity and corrosion resistance were also investigated using contact angle (CA) and electrochemical corrosion tests in acidic and salt solutions, respectively. Contact angle results showed that the naturally hydrophilic TiO$_2$/SS sample (CA ∼ 66$^\\deg$) turned into a superhydrophic surface (CA ∼ 148$^\\deg$) when it was covered by polystyrene fibres (PS/TiO2/SS). This observation can be attributed to the intrinsic hydrophobicity of organic polystyrene fibres (due to their low surface energy) and also to the existence of trapped air bubbles between fibres. Electrochemical corrosion tests showed that the corrosion rate was substantially decreased by using a protective bilayer (PS/TiO$_2$) from 33 to 0.39 mV/y for bare SS sample and from 0.01 to 0.003 mV/y for PS/TiO$_2$/SS sample in 1 M salt and acidic solutions, respectively. The superhydrophobic protective layer forms an obstacle against ionic exchange interactions. Therefore, it slows down the breaking of the surface oxidic layer on the metal substrate and prevents the metallic surface underneath from further corrosion.

  1. TiO2-Bioactive Glass Nanostructure Composite Films Produced by a Sol-Gel Method: In Vitro Behavior and UV-Enhanced Bioactivity

    Science.gov (United States)

    Omid-Bakhtiari, Marzie; Nasr-Esfahani, Mojtaba; Nourmohamadi, Abolghasem

    2014-01-01

    The aim of this study is to develop TiO2, titania, -based composite films for 316 stainless steel substrate and to improve their apatite-forming activity. A series of sol-gel derived bioactive glass (49S) and bioactive glass (49S)-TiO2 films were deposited on the 316L stainless steel substrates by the spin-coating method. Amorphous bioactive glass (49S) film and polycrystalline titania-bioactive glass composite films were obtained after annealing the deposited layers at 600 °C. The microstructure and in vitro bioactivity of the composite films as well as the effect of titania nanopowder content and ultra violet (UV) irradiation on the in vitro bioactivity were investigated by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). While bioactivity tests are often carried out within 28-day periods, SEM and EDS data show that, after soaking in SBF for just 7 days, the prepared composite surfaces are covered with an apatite layer. The grown apatite layer consists of spherulites formed by nanosized needle-like aggregates. Fourier transform infrared spectroscopy investigations confirm apatite formation and suggest that the formed apatite is carbonated.

  2. Enhanced photocatalytic performance of TiO2-ZnO hybrid nanostructures

    OpenAIRE

    Chun Cheng; Abbas Amini; Chao Zhu; Zuli Xu; Haisheng Song; Ning Wang

    2014-01-01

    We studied the photocatalytic properties of rational designed TiO2-ZnO hybrid nanostructures, which were fabricated by the site-specific deposition of amorphous TiO2 on the tips of ZnO nanorods. Compared with the pure components of ZnO nanorods and amorphous TiO2 nanoparticles, these TiO2-ZnO hybrid nanostructures demonstrated a higher catalytic activity. The strong green emission quenching observed from photoluminescence of TiO2-ZnO hybrid nanostructures implied an enhanced charge transfer/s...

  3. Synthesis, characterization and photocatalytic behavior of Ag doped TiO2 thin film

    Science.gov (United States)

    Bensouici, F.; Souier, T.; Dakhel, A. A.; Iratni, A.; Tala-Ighil, R.; Bououdina, M.

    2015-09-01

    In this study, structure, microstructure, optical properties and photocatalytic degradation of Rhodamine B (RhB) have been investigated in an aqueous heterogeneous media containing pure and Ag doped TiO2 nanostructures thin films which were prepared by a simple sol-gel route. Thermal analysis demonstrated that Ag content decreased the temperature of anatase-to-rutile phase transformation. X-ray diffraction analysis confirmed that the prepared nanostructures crystallize within anatase-type structure and that the dopant Ag ions were not fully incorporated within TiO2 host lattice, meanwhile both the refractive index and optical band gap were affected by Ag concentration. The photodegradation of Rhodamine B under UV-C radiation by using pure and Ag-doped TiO2 nanostructures showed that Ag played an important role in a significant improvement of the photodegradation efficiency and that the optimum content of Ag ions was found to be 0.5% molar ratio.

  4. Low temperature synthesis of hierarchical TiO2 nanostructures for high performance perovskite solar cells by pulsed laser deposition.

    Science.gov (United States)

    Yang, Bin; Mahjouri-Samani, Masoud; Rouleau, Christopher M; Geohegan, David B; Xiao, Kai

    2016-10-21

    A promising way to advance perovskite solar cells is to improve the quality of the electron transport material -e.g., titanium dioxide (TiO2) - in a direction that increases electron transport and extraction. Although dense TiO2 films are easily grown in solution, efficient electron extraction suffers due to a lack of interfacial contact area with the perovskites. Conversely, mesoporous films do offer high surface-area-to-volume ratios, thereby promoting efficient electron extraction, but their morphology is relatively difficult to control via conventional solution synthesis methods. Here, a pulsed laser deposition method was used to assemble TiO2 nanoparticles into TiO2 hierarchical architectures exhibiting an anatase crystal structure, and prototype solar cells employing these structures yielded power conversion efficiencies of ∼14%. Our approach demonstrates a way to grow high aspect-ratio TiO2 nanostructures for improved interfacial contact between TiO2 and perovskite materials, leading to high electron-hole pair separation and electron extraction efficiencies for superior photovoltaic performance. Compared to previous pulsed laser deposition-synthesized TiO2 mesoporous crystalline networks that needed post-thermal annealing at 500 °C to form mesoporous crystalline networks, our relatively low temperature (300 °C) TiO2 processing method may promote reduced energy-consumption during device fabrication, as well as enable compatibility with flexible polymer substrates such as polyimide.

  5. Nanostructured ZnO, TiO2, and Composite ZnO/TiO2 Films for Application in Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Myrsini Giannouli

    2013-01-01

    Full Text Available The effects of using composite semiconductor films on the efficiency and stability of dye-sensitized solar cells (DSSCs were investigated. Four different types of composite ZnO/TiO2 cells were developed and sensitized with the organic molecules Coumarin 343 (C343 and Rose Bengal (RB. A comparative assessment of the different composite cells was conducted, and the photovoltaic performance of single-semiconductor ZnO and TiO2 solar cells was also compared to that of the composite ZnO/TiO2 cells. It was observed that composite cells with ZnO/TiO2 ratio equal to 90/10 have comparable efficiency to single-semiconductor cells and have the advantage of higher stability. The effects of using various multicomponent electrolytes on the efficiency and stability of the ZnO/TiO2 cells were also investigated. It was observed that the combined properties of the materials used in these electrolytes enhance the efficiency of the composite ZnO/TiO2 cells.

  6. Enhanced photocatalytic performance of TiO2-ZnO hybrid nanostructures

    Science.gov (United States)

    Cheng, Chun; Amini, Abbas; Zhu, Chao; Xu, Zuli; Song, Haisheng; Wang, Ning

    2014-02-01

    We studied the photocatalytic properties of rational designed TiO2-ZnO hybrid nanostructures, which were fabricated by the site-specific deposition of amorphous TiO2 on the tips of ZnO nanorods. Compared with the pure components of ZnO nanorods and amorphous TiO2 nanoparticles, these TiO2-ZnO hybrid nanostructures demonstrated a higher catalytic activity. The strong green emission quenching observed from photoluminescence of TiO2-ZnO hybrid nanostructures implied an enhanced charge transfer/separation process resulting from the novel type II heterostructures with fine interfaces. The catalytic performance of annealing products with different TiO2 phase varied with the annealing temperatures. This is attributed to the combinational changes in Eg of the TiO2 phase, the specific surface area and the quantity of surface hydroxyl groups.

  7. Electrochemical formation of transparent nanostructured TiO2 film as an effective bifunctional layer for dye-sensitized solar cells.

    Science.gov (United States)

    Wu, Mao-Sung; Tsai, Chen-Hsiu; Wei, Tzu-Chien

    2011-03-14

    A bifunctional TiO(2) layer having an inner compact layer and an outer anchoring layer coated on fluorine-doped tin oxide (FTO) glass could reduce the charge recombination and interfacial contact resistance between FTO and the main TiO(2) layer; photoelectron conversion efficiency of cell was increased from 7.31 to 8.04% by incorporating the bifunctional layer.

  8. Photocatalytic Properties of TiO2 Porous Network Film.

    Science.gov (United States)

    Yu, Lianqing; Zhi, Qianqian; Huang, Chengxing; Zhang, Yaping; Dong, Kaituo; Neppolian, B

    2015-09-01

    Three-dimensional porous network TiO2 film (PW-film) and nanoparticles film were synthesized on surface of the Ti foil by a facile method to investigate both the photoelectrochemical and photocatalytic properties. The prepared samples were characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM) and X-ray diffraction spectroscopy (XRD) techniques. Methylene blue was used as a target molecule to estimate the photocatalytic activity of the films. Results revealed that the hydrothermal temperature and time have great influence on the crystal type and film morphology of TiO2 catalysts. A higher hydrothermal temperature is benefit for the formation of anatase phase of TiO2 nanotubes with PW-film, which had a large number of nodes. After investigation of the photoelectrochemical properties, a maximum photoconversion efficiency of 4.79% is observed for nanoparticles film with rutile phase of TiO2 under UV light illumination, which was incredible 2 times higher than that of the PW-film with anatase phase. It was shown that the morphology of TiO2 film contributes more significant effect on photocatalytic and photoelectric performance than its crystal type.

  9. Effect of molarity of TiO2 seeded-template to the growth of ZnO nanostructures

    Science.gov (United States)

    Asib, N. A. M.; Afaah, A. N.; Aadila, A.; Mahmud, M. R.; Lim, Y. C.; Alrokayan, Salman A. H.; Khan, Haseeb A.; Rusop, M.; Khusaimi, Z.

    2015-05-01

    ZnO nanostructures were deposited by solution-immersion method on TiO2 layers by sol-gel spin-coating technique. Seven layers of TiO2 were coated on glass substrates at different molarities, followed by annealing treatment and solution-immersion process in aqueous solution containing 1:1 ratio of 0.05 M of zinc nitrate hexahydrate (Zn(NO3)2.6H2O) and hexamethylenetetramine (HMTA) (C6H12N4). FESEM images confirmed that ZnO nanostructures grown on TiO2 seeded-template are in needle-like shape with smaller tip can be observed. Photoluminescence (PL) spectroscopy showed that as the molarity of TiO2 seeded- template increase, the intensity of PL emission at UV region decrease. UV emission peak for 0.10 M and 0.25 M are higher compared to UV emission peak film of 0.50 M and 1.00 M, which are too low. Meanwhile, the UV absorption properties of the nanostructured thin film for 0.25 M of TiO2 seeded-template was higher compared to other thin films.

  10. Modelling of nanostructured TiO2-based memristors

    Science.gov (United States)

    Shinde, S. S.; Dongle, T. D.

    2015-03-01

    The fourth fundamental circuit element memristor completes the missing link between charge and magnetic flux. It consists of the function of the resistor as well as memory in nonlinear fashion. The property of the memristor depends on the magnitude and direction of applied potential. This unique property makes it the primitive building block for many applications such as resistive memories, soft computing, neuromorphic systems and chaotic circuits etc. In this paper we report TiO2-based nanostructured memristor modelling. The present memristor model is constructed in MATLAB environment with consideration of the linear drift model of memristor. The result obtained from the linear drift model is well matched with earlier reported results by other research groups.

  11. STS study of TiO2 film and Pt-deposited TiO2 film in air

    Institute of Scientific and Technical Information of China (English)

    Zhang Min; Jin Zhensheng

    2004-01-01

    Direct investigation of the electronic structure of catalyst surfaces on the near-atomic scale in general has not been impossible in the past. However, with the advent of the scanning tunneling microscope (STM), the opportunity arises for incorporating the scanning tunneling spectroscopy (STS) for correlation in-situ surface electronic structure with topography on a sub-nanometer scale. In this paper, we report the STS results of thin film TiO2 and Pt-deposited TiO2 annealed at 450℃. It was found that the TiO2 semiconductor changes from n-type to p-type after Pt deposition.Fig. 1 shows the surface electronic property (Ⅰ-Ⅴ curve) of thin TiO2 film measured in air by STS. A steep descent of the anodic tunneling current at ca.- 1.0 Ⅴ and a rapid ascent of cathodic tunneling current at ca. +2.0V. The zero bias represents the Fermi level (Ef). Ef is situated at the Ecb side indicating that the thin TiO2 film possesses the same band gap as that of bulk TiO2 phase ( Egs =3.0 to 3.2 eV). For the sample of Pt-deposited TiO2 film, Pt/(Pt+Ti+O) atomic ratio≈0.2, which indicates that the surface of TiO2 film is partly covered by Pt particles, and there are two types of Ⅰ-Ⅴ curves to be detected. One of them (Fig.2a)is attributed to the electronic property of TiO2, which has same Egs as that shown in Fig. 1. However, the Ef is transferred to valence side (△≈1eV). This phenomenon hints that TiO2 is doped by an impurity which can introduce h+ into TiO2 lattice.Such a type of defects may be described by Ti1-xPtxO2(h )2x, here Pt+2 as a substitutional site of Ti+4. Fig.2b is the Ⅰ-Ⅴ curve of a Pt particle situated on a TiO2 particle contained Ti1-xPtxO2(h )2x.

  12. Adsorption and solar light decomposition of acetone on anatase TiO2 and niobium doped TiO2 thin films.

    Science.gov (United States)

    Mattsson, Andreas; Leideborg, Michael; Larsson, Karin; Westin, Gunnar; Osterlund, Lars

    2006-01-26

    Adsorption and solar light decomposition of acetone was studied on nanostructured anatase TiO2 and Nb-doped TiO2 films made by sol-gel methods (10 and 20 mol % NbO2.5). A detailed characterization of the film materials show that films contain only nanoparticles with the anatase modification with pentavalent Nb oxide dissolved into the anatase structure, which is interpreted as formation of substituted Nb=O clusters in the anatase lattice. The Nb-doped films displayed a slight yellow color and an enhanced the visible light absorption with a red-shift of the optical absorption edge from 394 nm for the pure TiO2 film to 411 nm for 20 mol % NbO2.5. In-situ Fourier transform infrared (FTIR) transmission spectroscopy shows that acetone adsorbs associatively with eta1-coordination to the surface cations on all films. On Nb-doped TiO2 films, the carbonyl bonding to the surface is stabilized, which is evidenced by a lowering of the nu(C=O) frequency by about 20 cm(-1) to 1672 cm(-1). Upon solar light illumination acetone is readily decomposed on TiO2, and stable surface coordinated intermediates are formed. The decomposition rate is an order of magnitude smaller on the Nb-doped films despite an enhanced visible light absorption in these materials. The quantum yield is determined to be 0.053, 0.004 and 0.002 for the pure, 10% Nb:TiO2, and 20%Nb:TiO2, respectively. Using an interplay between FTIR and DFT calculations we show that the key surface intermediates are bidentate bridged formate and carbonate, and H-bonded bicarbonate, respectively, whose concentration on the surface can be correlated with their heats of formation and bond strength to coordinatively unsaturated surface Ti and Nb atoms at the surface. The oxidation rate of these intermediates is substantially slower than the initial acetone decomposition rate, and limits the total oxidation rate at t>7 min on TiO2, while no decrease of the rate is observed on the Nb-doped films. The rate of degradation of key surface

  13. Light scattering characteristicof TiO2 nanocrystalline porous films

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    TiO2 nanocrystalline porous films consisting of binary particles mixture (mean diameters of 12 and 100 nm) are capable of increasing the light absorption due to the possession of large specific surface area and light scattering property. The simultaneous reduction of the film thickness leads to a decrease of the recombination loss during electron transport and an increase of the photocurrent efficiency.

  14. Studies of surface morphology and optical properties of ZnO nanostructures grown on different molarities of TiO2 seed layer

    Science.gov (United States)

    Asib, N. A. M.; Afaah, A. N.; Aadila, A.; Rusop, M.; Khusaimi, Z.

    2016-07-01

    Titanium dioxide (TiO2) seed layer was prepared by using sol-gel spin-coating technique, followed by growth of 0.01 M of Zinc oxide (ZnO) nanostructures by solution-immersion. The molarities of TiO2 seed layer were varied from 1.1 M to 0.100 M on glass substrates. The nanostructures thin films were characterized by Field Emission Scanning Electrons Microscope (FESEM), Photoluminescence (PL) spectroscopy and Ultraviolet-Visible (UV-Vis) spectroscopy. FESEM images demonstrate that needle-like ZnO nanostructures are formed on all TiO2 seed layer. The smallest diameter of needle-like ZnO nanostructures (90.3 nm) were deposited on TiO2 seed layer of 0.100 M. PL spectra of the TiO2: ZnO nanostructures thin films show the blue shifted emissions in the UV regions compared to the ZnO thin film. Meanwhile, UV-vis spectra of films display high absorption in the UV region and high trasparency in the visible region. The highest absorbance at UV region was recorded for sample which has 0.100 M of TiO2 seed layer.

  15. Morphological influence of TiO2 nanostructures (nanozigzag, nanohelics and nanorod) on photocatalytic degradation of organic dyes

    Science.gov (United States)

    Khan, Sadaf Bashir; Hou, Mengjing; Shuang, Shuang; Zhang, Zhengjun

    2017-04-01

    Hierarchical nanostructures have drawn significant attention and incredible performance in photodriven chemical conversion area due to its unique physicochemical properties. Herein, we study the morphological influence of TiO2 nanostructures on photocatalytic degradation of different organic dyes methyl blue, methyl violet and methyl orange present in industrial wastewater. Nanorod, nanohelics and nanozigzag TiO2 nanofilms were fabricated by using galancing angle deposition technique (GLAD). TiO2 nanofilms were characterized by scanning electron microscope (SEM), X-ray powder diffraction (XRD), and raman analysis. BET surface area analysis were carried out by using nitrogen adsorption desorption curves. The results show that TiO2 morphology had great influence on photocatalytic degradation of organic dyes due to difference in specific surface area and pore volume of nanostructures. The photocatalytic degradation experiments were carried out for three hours under UV-vis light irradiation. Catalysis recycling and organic dyes concentration influence were also studied. In case of high concentration of organic dyes, negligible degradation rate is observed. TiO2 nanozigzag films show better degradation performance than nanohelics and nanorod due to presence of large surface area for reaction, higher porosity with dispersion of active sites at different length scales of pores and presence of oxygen vacancies.

  16. KARAKTERISTIK FILM TIPIS TiO2 DOPING NIOBIUM

    Directory of Open Access Journals (Sweden)

    Bilalodin

    2010-05-01

    Full Text Available Niobium (Nb doped Titanium dioxide (TiO2 thin films have been successfully grown using spin coating method. Characterizations of thin films was carried out using EDAX (Energy Dispersion Analysis for X-Ray, XRD (X-Ray Diffaction and SEM (Scanning Electron Microscope to determine the microstructure of thin films. Determination microstructure, particularly of crystal structure was examined using ICDD data, whereas porosity calculation was done using the toolbox application on Matlab 6.1 software. EDAX, XRD and SEM characterization show that the thin films grown well at the Si substrates with the (002 field orientation is dominant and the thin film has the rutile structure. The TiO2 : Nb thin films product have granules round, uniform grain size and porosity value of about 41%.

  17. Structural and electrical properties of TiO2 thin films

    Science.gov (United States)

    Rao, M. C.; Ravindranadh, K.; Shekhawat, M. S.

    2016-05-01

    Titanium dioxide (TiO2) is traditionally the most widely used white pigment due to its high refractive index. Titanium dioxide (TiO2) is traditionally the most widely used white pigment due to its high refractive index. TiO2 has received considerable attention and it has been used for optical coatings, photo-catalysis agents, gas sensors and solar cells. In this work, nano-structured TiO2 thin films were grown by pulsed laser deposition (PLD) technique on glass substrates. The prepared thin films were annealed from 400-600 °C in air for a period of 2 hours. Effect of annealing on the structural and electrical properties was studied. X-ray diffraction pattern exhibits peaks correspond to tetragonal anatase phase of TiO2 and the evaluated average crystallite size of the prepared materials are in the range of 16 to 30 nm. Electrical properties of the prepared samples are analyzed.

  18. The design, fabrication, and photocatalytic utility of nanostructured semiconductors: focus on TiO2-based nanostructures.

    Science.gov (United States)

    Banerjee, Arghya Narayan

    2011-02-15

    Recent advances in basic fabrication techniques of TiO2-based nanomaterials such as nanoparticles, nanowires, nanoplatelets, and both physical- and solution-based techniques have been adopted by various research groups around the world. Our research focus has been mainly on various deposition parameters used for fabricating nanostructured materials, including TiO2-organic/inorganic nanocomposite materials. Technically, TiO2 shows relatively high reactivity under ultraviolet light, the energy of which exceeds the band gap of TiO2. The development of photocatalysts exhibiting high reactivity under visible light allows the main part of the solar spectrum to be used. Visible light-activated TiO2 could be prepared by doping or sensitizing. As far as doping of TiO2 is concerned, in obtaining tailored material with improved properties, metal and nonmetal doping has been performed in the context of improved photoactivity. Nonmetal doping seems to be more promising than metal doping. TiO2 represents an effective photocatalyst for water and air purification and for self-cleaning surfaces. Additionally, it can be used as an antibacterial agent because of its strong oxidation activity and superhydrophilicity. Therefore, applications of TiO2 in terms of photocatalytic activities are discussed here. The basic mechanisms of the photoactivities of TiO2 and nanostructures are considered alongside band structure engineering and surface modification in nanostructured TiO2 in the context of doping. The article reviews the basic structural, optical, and electrical properties of TiO2, followed by detailed fabrication techniques of 0-, 1-, and quasi-2-dimensional TiO2 nanomaterials. Applications and future directions of nanostructured TiO2 are considered in the context of various photoinduced phenomena such as hydrogen production, electricity generation via dye-sensitized solar cells, photokilling and self-cleaning effect, photo-oxidation of organic pollutant, wastewater management, and

  19. The design, fabrication, and photocatalytic utility of nanostructured semiconductors: focus on TiO2-based nanostructures

    Directory of Open Access Journals (Sweden)

    Arghya Narayan Banerjee

    2011-02-01

    Full Text Available Arghya Narayan BanerjeeSchool of Mechanical Engineering, Yeungnam University, Gyeongsan, South KoreaAbstract: Recent advances in basic fabrication techniques of TiO2-based nanomaterials such as nanoparticles, nanowires, nanoplatelets, and both physical- and solution-based techniques have been adopted by various research groups around the world. Our research focus has been mainly on various deposition parameters used for fabricating nanostructured materials, including TiO2-organic/inorganic nanocomposite materials. Technically, TiO2 shows relatively high reactivity under ultraviolet light, the energy of which exceeds the band gap of TiO2. The development of photocatalysts exhibiting high reactivity under visible light allows the main part of the solar spectrum to be used. Visible light-activated TiO2 could be prepared by doping or sensitizing. As far as doping of TiO2 is concerned, in obtaining tailored material with improved properties, metal and nonmetal doping has been performed in the context of improved photoactivity. Nonmetal doping seems to be more promising than metal doping. TiO2 represents an effective photocatalyst for water and air purification and for self-cleaning surfaces. Additionally, it can be used as an antibacterial agent because of its strong oxidation activity and superhydrophilicity. Therefore, applications of TiO2 in terms of photocatalytic activities are discussed here. The basic mechanisms of the photoactivities of TiO2 and nanostructures are considered alongside band structure engineering and surface modification in nanostructured TiO2 in the context of doping. The article reviews the basic structural, optical, and electrical properties of TiO2, followed by detailed fabrication techniques of 0-, 1-, and quasi-2-dimensional TiO2 nanomaterials. Applications and future directions of nanostructured TiO2 are considered in the context of various photoinduced phenomena such as hydrogen production, electricity generation via

  20. Preparation and Photocatalytic Property of Porous TiO2 Film with Net-like Framework

    Institute of Scientific and Technical Information of China (English)

    XU Rong-guo; YAO Jian-xi; LAI Xiao-yong; MAO Dan; XING Chao-jian; WANG Dan

    2009-01-01

    By the UV-curing method, a porous TiO2 film with net-like framework has been prepared. The characte-rization results of the porous TiO2 film by means of SEM, TEM, XRD, and N2 adsorption-desorption analysis show that the net-like framework of the porous TiO2 film is composed of TiO2 nanoparticles, forming three dimensional porous structure. The porous TiO2 film exhibits higher photocatalytic activity for the degradation of methylene blue(MB) dye compared with the conventional dense TiO2 film.

  1. Low-Temperature Preparation of Amorphous-Shell/Nanocrystalline-Core Nanostructured TiO2 Electrodes for Flexible Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Dongshe Zhang

    2008-01-01

    Full Text Available An amorphous shell/nanocrystalline core nanostructured TiO2 electrode was prepared at low temperature, in which the mixture of TiO2 powder and TiCl4 aqueous solution was used as the paste for coating a film and in this film amorphous TiO2 resulted from direct hydrolysis of TiCl4 at 100∘C sintering was produced to connect the particles forming a thick crack-free uniform nanostructured TiO2 film (12 μm, and on which a photoelectrochemical solar cell-based was fabricated, generating a short-circuit photocurrent density of 13.58 mA/cm2, an open-circuit voltage of 0.647 V, and an overall 4.48% light-to-electricity conversion efficiency under 1 sun illumination.

  2. Synthesis of anatase and rutile TiO2 nanostructures from natural ilmenite

    Science.gov (United States)

    Wahyuingsih, Sayekti; Ramelan, Ari Handono; Pramono, Edi; Sulistya, Ariantama Djati; Argawan, Panji Rofa; Dharmawan, Frenandha Dwi; Rinawati, Ludfiaastu; Hanif, Qonita Awliya; Sulistiyono, Eko; Firdiyono, Florentinus

    2016-02-01

    Nanostructure anatase and rutile type TiO2 were synthesized from dissolution roasted ilmenite from natural ilmenite sand as the starting materials. Anatase TiO2 and rutile TiO2 (high crystallinity) with the diameters of 20-100 nm were obtained by calcined soluble ilmenite sand produced by leaching process. Calcinations of the xerogel TiO2 from liquor products were conducted for 4 hours at temperature of 450 °C. The samples were characterized by XRD (X-ray diffraction), STA (simultant thermal analysis), TEM (Transmission Electron Microscopy), and BET surface area. Titania Anatase-Rutile form as a mixture were produced by titania slag with the hydrolysis product. While, in another route, complete titania anatase phase was produced through hydrolysis and condensation steps of leach liquors. This synthesis methods provide a simple route to fabricate nanostructure TiO2 from low cost material.

  3. Three-dimensional observation of TiO2 nanostructures by electron tomography

    KAUST Repository

    Suh, Young Joon

    2013-03-01

    Three-dimensional nanostructures of TiO2 related materials including nanotubes, electron acceptor materials in hybrid polymer solar cells, and working electrodes of dye sensitized solar cells (DSSCs) were visualized by electron tomography as well as TEM micrographs. The regions on the wall of TiO2 nanotubes where the streptavidins were attached were elucidated by electron tomogram analysis. The coverage of TiO2 nanotubes by streptavidin was also investigated. The TiO2 nanostructures in hybrid polymer solar cells made by sol-gel and atomic layer deposition (ALD) methods and the morphologies of pores between TiO2 particles in DSSCs were also observed by reconstructed three-dimensional images made by electron tomography. © 2012 Elsevier Ltd.

  4. TiO2 Thin Film UV Detectors Deposited by DC Reactive Magnetron Sputtering

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li-wei; YAO Ning; ZHANG Bing-lin; FAN Zhi-qin; YANG Shi-e; LU Zhan-ling

    2004-01-01

    Crystalline TiO2 thin films were prepared by DC reactive magnetron sputtering on indium-tin oxide(ITO) thin film deposited on quartz substrate, the photoconductive UV detector on TiO2 thin films was based on a sandwich structure of C/ TiO2/ITO. The measurement of the I-V characteristics for these devices shows good ohmic contact. The photoresponse of TiO2 thin films was analyzed at different bias voltage. Voltage.

  5. Enhanced photoelectrochemical activity by nanostructured V2O5/TiO2 bilayer

    Science.gov (United States)

    Mumtaz, Asad; Mohamed, Norani Muti; Saheed, Mohamed Shuaib Mohamed; Yar, Asfand; Irshad, Muhammad Imran

    2016-11-01

    Hydrogen production by splitting of water using solar means is a renewable alternative and is a need of the hour. The generation of hydrogen is studied using nanostructured V2O5/TiO2 bilayer photoctatalyst synthesized by two different methods. The solution deposition followed by annealing and flame oxidized methods are applied to deposit the nanostructured V2O5 onto TiO2 nanorod arrays. These two methods are compared and studied using X-ray diffraction, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), electron energy loss spectrum and photoelectrochemical study. The morphological study provides the optimized surface area of the TiO2 nanorod arrays. It shows that 0.45 mL tetra butyl titanate at 180C shows the improved surface area. It also differentiates the 3D network as morphology of nanostructured V2O5/TiO2 bilayer photoctatalyst synthesized by flame oxidation method. Electron energy loss spectrum confirms the presence of respective elemental states of V2O5/TiO2 bilayer photoctatalyst. Photoelectrochemical studies show the photocurrent density of 7.89µA/cm2 at 0 V vs Ag/AgCl using flame oxidized nanostructured V2O5/TiO2 nanorod arrays. This study explores the potential of flame oxidized synthesis of nanostructured photocatalysts.

  6. Combination of TiO2-Film Photocatalysis and Ultrafiltration to Treat Wastewater

    OpenAIRE

    Shu-Hai You; Ming-Hua Guo

    2013-01-01

    In this study, a combination of TiO2-film photocatalysis reactor and ultrafiltration was used treat the secondary effluent from the manufacturing of thin film transistor-liquid crystal display (TFT-LCD). TiO2 particles, as a photocatalyst, were immobilized on silica glass to form TiO2-film by the sol-gel and dip coating methods. TiO2-film photocatalysis was done within three parameters, including number of coating times of TiO2-film, wavelengths of UV light source, and operating time. During...

  7. 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).

  8. Effects of electron beam irradiation on the photoelectrochemical properties of TiO2 film for DSSCs

    Science.gov (United States)

    Kim, Hyun-Bin; Park, Dong-Won; Jeun, Joon-Pyo; Oh, Seung-Hwan; Nho, Young-Chang; Kang, Phil-Hyun

    2012-08-01

    iO2 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.

  9. Reason for the loss of hydrophilicity of TiO2 film and its photocatalytic regeneration

    Institute of Scientific and Technical Information of China (English)

    殷好勇; 金振声; 张顺利; 王守斌; 张治军

    2002-01-01

    TiO2 film was prepared on soda-lime glass by sol-gel method. The water contact angle (θw) of the fresh TiO2 film is 0o. During storage in air, the surface of TiO2 film is gradually converted to the hydrophobic state. XPS and ITD results reveal that it is due to the adsorption of organic contaminants on TiO2 surface in air ambience. The lost hydrophilicity of TiO2 film can be regenerated by UV illumination.

  10. Transparent TiO2 nanowire networks via wet corrosion of Ti thin films for dye-sensitized solar cells

    Science.gov (United States)

    Shin, Eunhye; Jin, Saera; Hong, Jongin

    2017-09-01

    Transparent TiO2 nanowire networks were prepared by corrosion of Ti thin films on F-doped SnO2 glass substrates in an alkaline (potassium hydroxide: KOH) solution. The formation of the porous TiO2 nanostructures from the Ti thin films was thoroughly investigated. Dye-sensitized solar cells with a photoanode of 1.2-μm-thick nanowire networks exhibit an average optical transmittance of 40% in the visible light region and a power conversion efficiency of 1.0% under one sun illumination.

  11. Interposition fixing structure of TiO2 film deposited on activated carbon fibers

    Institute of Scientific and Technical Information of China (English)

    FU Ping-feng; LUAN Yong; DAI Xue-gang

    2006-01-01

    The immobilized photocatalyst, TiO2 film supported on activated carbon fibers (TiO2/ACFs) prepared with molecular adsorption-deposition (MAD), exhibits high stability in cyclic photodegradation runs. The interposition fixing structure between TiO2 film and carbon fiber was investigated by means of SEM-EDX, XRD, XPS and FTIR, and a model was proposed to explain this structure. With SEM examination of carbon fiber surface after removing the deposited TiO2 film, a residual TiO2 super-thin film was found to exist still. By determining surface groups on ACFs, titanium sulfate (Ti2(SO4)3) in burnt remainders of the TiO2/ACFs was thought to be formed with an interfacial reaction between TiO2 film and carbon fibers. These provide some evidence of firm attachment of TiO2 film to carbon fiber surface. In the consideration of characteristics of the MAD, the deposition mechanism of TiO2 film on ACFs was proposed, and the interposition fixing structure was inferred to intercrossedly form between TiO2 film and ACFs' surface. This structure leaded to firm attachment and high stability of the TiO2 film.

  12. One-Dimensional TiO2 Nanostructured Photoanodes: From Dye-Sensitised Solar Cells to Perovskite Solar Cells

    Directory of Open Access Journals (Sweden)

    Jung-Ho Yun

    2016-12-01

    Full Text Available This review presents one dimensional (1D TiO2 nanostructured photoanodes for next generation solar cells such as dye-sensitised solar cells (DSCs and perovskite solar cells (PSCs. Due to the unique morphological properties, 1D TiO2 nanostructures can act as express electron channels as well as light scattering layer, leading to improved charge transport properties, such as charge separation, electron injection, and electron lifetime, and light harvesting efficiency. As 1D TiO2 nanostructures are applied to solar cells, 1D TiO2 nanostructures should be further modified to overcome some drawbacks. In this review, we have described some solutions by introducing various 1D TiO2 synthetic methods and device fabrication processes for solar cell applications, where we have described some important surface engineering and hierarchical device design strategies that facilitate charge transport and light utilisation in 1D TiO2 nanostructured photoanode system.

  13. High-performance ethanol gas sensor using TiO2 nanostructures

    Science.gov (United States)

    Priyanka, K. P.; Vattappalam, S. C.; Sankararaman, S.; Balakrishna, K. M.; Varghese, Thomas

    2017-07-01

    TiO2 nanostructures were synthesized by simple chemical routes. As-synthesized nanostructures were characterized using X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, high-resolution transmission electron microscopy and selected area diffraction patterns. In the present work, the sensing element was fabricated as thin pellets of TiO2 nanoparticles without using any sensitizers coating. A novel approach of adopting gas sensing measurements of ethanol vapours at a low pressure condition inside a vacuum system has been achieved. All the samples show high sensor response towards ethanol vapour detection at relatively low operating temperatures. Thus, a low-cost industrial production of efficient ethanol gas sensor with good response and recovery time is possible with the synthesized TiO2 nanostructures.

  14. TiO 2 Thin Films Prepared via Adsorptive Self-Assembly for Self-Cleaning Applications

    KAUST Repository

    Xi, Baojuan

    2012-02-22

    Low-cost controllable solution-based processes for preparation of titanium oxide (TiO 2) thin films are highly desirable, because of many important applications of this oxide in catalytic decomposition of volatile organic compounds, advanced oxidation processes for wastewater and bactericidal treatments, self-cleaning window glass for green intelligent buildings, dye-sensitized solar cells, solid-state semiconductor metal-oxide solar cells, self-cleaning glass for photovoltaic devices, and general heterogeneous photocatalysis for fine chemicals etc. In this work, we develop a solution-based adsorptive self-assembly approach to fabricate anatase TiO 2 thin films on different glass substrates such as simple plane glass and patterned glass at variable compositions (normal soda lime glass or solar-grade borofloat glass). By tuning the number of process cycles (i.e., adsorption-then-heating) of TiO 2 colloidal suspension, we could facilely prepare large-area TiO 2 films at a desired thickness and with uniform crystallite morphology. Moreover, our as-prepared nanostructured TiO 2 thin films on glass substrates do not cause deterioration in optical transmission of glass; instead, they improve optical performance of commercial solar cells over a wide range of incident angles of light. Our as-prepared anatase TiO 2 thin films also display superhydrophilicity and excellent photocatalytic activity for self-cleaning application. For example, our investigation of photocatalytic degradation of methyl orange indicates that these thin films are indeed highly effective, in comparison to other commercial TiO 2 thin films under identical testing conditions. © 2012 American Chemical Society.

  15. TiO2 thin films prepared via adsorptive self-assembly for self-cleaning applications.

    Science.gov (United States)

    Xi, Baojuan; Verma, Lalit Kumar; Li, Jing; Bhatia, Charanjit Singh; Danner, Aaron James; Yang, Hyunsoo; Zeng, Hua Chun

    2012-02-01

    Low-cost controllable solution-based processes for preparation of titanium oxide (TiO(2)) thin films are highly desirable, because of many important applications of this oxide in catalytic decomposition of volatile organic compounds, advanced oxidation processes for wastewater and bactericidal treatments, self-cleaning window glass for green intelligent buildings, dye-sensitized solar cells, solid-state semiconductor metal-oxide solar cells, self-cleaning glass for photovoltaic devices, and general heterogeneous photocatalysis for fine chemicals etc. In this work, we develop a solution-based adsorptive self-assembly approach to fabricate anatase TiO(2) thin films on different glass substrates such as simple plane glass and patterned glass at variable compositions (normal soda lime glass or solar-grade borofloat glass). By tuning the number of process cycles (i.e., adsorption-then-heating) of TiO(2) colloidal suspension, we could facilely prepare large-area TiO(2) films at a desired thickness and with uniform crystallite morphology. Moreover, our as-prepared nanostructured TiO(2) thin films on glass substrates do not cause deterioration in optical transmission of glass; instead, they improve optical performance of commercial solar cells over a wide range of incident angles of light. Our as-prepared anatase TiO(2) thin films also display superhydrophilicity and excellent photocatalytic activity for self-cleaning application. For example, our investigation of photocatalytic degradation of methyl orange indicates that these thin films are indeed highly effective, in comparison to other commercial TiO(2) thin films under identical testing conditions.

  16. Biocompatibility of different nanostructured TiO2 scaffolds and their potential for urologic applications.

    Science.gov (United States)

    Imani, Roghayeh; Pazoki, Meysam; Zupančič, Daša; Kreft, Mateja Erdani; Kralj-Iglič, Veronika; Veranič, Peter; Iglič, Aleš

    2016-11-01

    Despite great efforts in tissue engineering of the ureter, urinary bladder, and urethra, further research is needed in order to improve the patient's quality of life and minimize the economic burden of different lower urinary tract disorders. The nanostructured titanium dioxide (TiO2) scaffolds have a wide range of clinical applications and are already widely used in orthopedic or dental medicine. The current study was conducted to synthesize TiO2 nanotubes by the anodization method and TiO2 nanowires and nanospheres by the chemical vapor deposition method. These scaffolds were characterized with scanning electron microscopy (SEM) and X-ray diffraction (XRD) methods. In order to test the urologic applicability of generated TiO2 scaffolds, we seeded the normal porcine urothelial (NPU) cells on TiO2 nanotubes, TiO2 nanowires, TiO2 nanospheres, and on the standard porous membrane. The viability and growth of the cells were monitored everyday, and after 3 weeks of culturing, the analysis with scanning electron microscope (SEM) was performed. Our results showed that the NPU cells were attached on all scaffolds; they were viable and formed a multilayered epithelium, i.e., urothelium. The apical plasma membrane of the majority of superficial NPU cells, grown on all three different TiO2 scaffolds and on the porous membrane, exhibited microvilli; thus, indicating that they were at a similar differentiation stage. The maximal caliper diameter measurements of superficial NPU cells revealed significant alterations, with the largest cells being observed on nanowires and the smallest ones on the porous membrane. Our findings indicate that different nanostructured TiO2 scaffolds, especially nanowires, have a great potential for tissue engineering and should be further investigated for various urologic applications.

  17. Photocatalytic Property of TiO2 Films Deposited by Pulsed DC Magnetron Sputtering

    Institute of Scientific and Technical Information of China (English)

    Wenjie ZHANG; Shenglong ZHU; Ying LI; Fuhui WANG

    2004-01-01

    TiO2 thin films were prepared by DC magnetron sputtering with the oxygen flow rate higher than the threshold. The film deposited for 5 h was of anatase phase with a preferred orientation along the direction, but the films deposited for 2 and 3 h were amorphous. The transmittance and photocatalytic activity of the TiO2 films increased constantly with increasing film thickness. When the annealing temperature was lower than 700℃, only anatase grew in the TiO2 film. TiO2 phase changed from anatase to rutile when the annealing temperature was above 800℃. The photocatalytic activity decreased with increasing annealing temperature.

  18. Facile Synthesis and Tensile Behavior of TiO2 One-Dimensional Nanostructures

    Directory of Open Access Journals (Sweden)

    Li Shu-you

    2009-01-01

    Full Text Available Abstract High-yield synthesis of TiO2 one-dimensional (1D nanostructures was realized by a simple annealing of Ni-coated Ti grids in an argon atmosphere at 950 °C and 760 torr. The as-synthesized 1D nanostructures were single crystalline rutile TiO2 with the preferred growth direction close to [210]. The growth of these nanostructures was enhanced by using catalytic materials, higher reaction temperature, and longer reaction time. Nanoscale tensile testing performed on individual 1D nanostructures showed that the nanostructures appeared to fracture in a brittle manner. The measured Young’s modulus and fracture strength are ~56.3 and 1.4 GPa, respectively.

  19. Properties of TiO2 Thin Films Prepared by Magnetron Sputtering

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    With rapid progressive application of TiO2 thin films, magnetron sputtering becomes a very interesting method to prepare such multi-functional thin films. This paper focuses on influences of various deposition processes and deposition rate on the structures and properties of TiO2 thin films. Anatase, rutile or amorphous TiO2 films with various crystalline structures and different photocatalytic, optical and electrical properties can be produced by varying sputtering gases, substrate temperature, annealing process, deposition rate and the characteristics of magnetron sputtering. This may in turn affect the functions of TiO2 films in many applications. Furthermore, TiO2-based composites films can overcome many limitations and improve the properties of TiO2 films.

  20. Influence of coating material on laser damage threshold of TiO2 films

    Institute of Scientific and Technical Information of China (English)

    Jianke Yao; Zhengxiu Fan; Hongbo He; Jianda Shao

    2007-01-01

    @@ The optical property, structure, surface properties (roughness and defect density) and laser-induced damage threshold (LIDT) of TiO2 films deposited by electronic beam (EB) evaporation of TiO2 (rutile), TiO2 (anatase) and TiO2 + Ta2O5 composite materials are comparatively studied. All films show the polycrystalline anatase TiO2 structure. The loose sintering state and phase transformation during evaporating TiO2 anatase slice lead to the high surface defect density, roughness and extinction coefficient, and low LIDT of films. The TiO2 + Ta2O5 composite films have the lowest extinction coefficient and the highest LIDT among all samples investigated. Guidance of selecting materials for high LIDT laser mirrors is given.OCIS codes: 310.3840, 140.3330.

  1. Electrochemical Behavior of TiO2 Nanoparticle Doped WO3 Thin Films

    Directory of Open Access Journals (Sweden)

    Suvarna R. Bathe

    2014-01-01

    Full Text Available Nanoparticle TiO2 doped WO3 thin films by pulsed spray pyrolysis technique have been studied on fluorine tin doped (FTO and glass substrate. XRD shows amorphous nature for undoped and anatase phase of TiO2 having (101 plane for nanoparticle TiO2 doped WO3 thin film. SEM shows microfibrous reticulated porous network for WO3 with 600 nm fiber diameter and nanocrystalline having size 40 nm for TiO2 nanoparticle doped WO3 thin film. TiO2 nanoparticle doped WO3 thin film shows ~95% reversibility due to may be attributed to nanocrystalline nature of the film, which helpful for charge insertion and deinsertion process. The diffusion coefficient for TiO2 nanoparticle doped WO3 film is less than undoped WO3.

  2. Structural analysis of TiO2 and TiO2-Ag thin films and their antibacterial behaviors

    Science.gov (United States)

    Hsieh, J. H.; Yu, R. B.; Chang, Y. K.; Li, C.

    2012-01-01

    TiO2 (rutile and anatase) thin films was first prepared using reactive sputtering, in an Ar+O2 plasma. In the 2nd stage of the experiment, various amounts (3, 7, and 10 at. %) of Ag was doped into the rutile film in order to form TiO2-Ag thin films. These films were annealed for one hour in Ar atmosphere, at 300, 400, and 500 °C. The films' structures were then examined using X-ray diffractometry. FESEM (field-emission scaning electron microscopy) was used to investigate the surface emergence of Ag particles. As for the examination of optical band gaps and absorption of these films, UV-Vis-NIR photometer was used. The results show that, in as-deposited condition, the addition of Ag might disrupt the growth of crystalline structure and cause the formation of amorphous films. After annealing, it is found that the structure tends to become anatase phase which is a metastable phase between amorphous titanium oxide and rutile. More importantly, the absorption of the Ag-doped films would be enhanced in the visible-light range. Some of the enhancement is clearly due to plasmon resonance effect. The Ag-doped samples have shown some antibacterial effect in dark. When irradiated with light, the samples show a synergistic behavior combining the bactericidal effect of Ag ions and photocatalytic effect of TiO2.

  3. Single step synthesis of rutile TiO2 nanoflower array film by chemical bath deposition method

    Science.gov (United States)

    Dhandayuthapani, T.; Sivakumar, R.; Ilangovan, R.

    2016-05-01

    Titanium oxide (TiO2) nanostructures such as nanorod arrays, nanotube arrays and nanoflower arrays have been extensively investigated by the researchers. Among them nanoflower arrays has shown superior performance than other nanostructures in Dye sensitized solar cell, photocatalysis and energy storage applications. Herein, a single step synthesis for rutile TiO2 nanoflower array films suitable for device applications has been reported. Rutile TiO2 nanoflower thin film was synthesized by chemical bath deposition method using NaCl as an additive. Bath temperature induced evolution of nanoflower thin film arrays was observed from the morphological study. X-ray diffraction study confirmed the presence of rutile phase polycrystalline TiO2. Micro-Raman study revealed the presence of surface phonon mode at 105 cm-1 due to the phonon confinement effect (finite size effect), in addition with the rutile Raman active modes of B1g (143 cm-1), Eg (442 cm-1) and A1g (607 cm-1). Further, the FTIR spectrum confirmed the presence of Ti-O-Ti bonding vibration. The Tauc plot showed the direct energy band gap nature of the film with the value of 2.9 eV.

  4. Synthesis and characterization of Ag doped TiO2 heterojunction films and their photocatalytic performances

    Science.gov (United States)

    Demirci, Selim; Dikici, Tuncay; Yurddaskal, Metin; Gultekin, Serdar; Toparli, Mustafa; Celik, Erdal

    2016-12-01

    In this study, undoped and silver (Ag) doped titanium dioxide (TiO2) films were successfully synthesized by sol-gel spin coating technique on the Si substrates. Photocatalytic activities of the TiO2 films with different Ag content were investigated for the degradation of methylene blue (MB) under UV light irradiation. The crystal phase structure, surface morphology, chemical and optical properties of Ag-doped TiO2 films were characterized using an X-ray diffractometer (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), UV-vis spectrophotometer, and FTIR spectrophotometer. The results showed that the Ag-doped TiO2 films calcined at 500 °C had the crystalline anatase phases and the surface morphologies with some cracks. Ag substitution into TiO2 matrix enhanced the photocatalytic activity of TiO2 films under UV light irradiation as compared to the undoped TiO2 film. Furthermore, the results indicated that the 0.7% Ag doped TiO2 film exhibited a superior photocatalytic activity than that of undoped and other Ag-doped TiO2 films. This study demonstrated the potential of an application of Ag doped films to efficiently treat dissolved organic contaminants in water.

  5. Optimum Nanoporous TiO2 Film and Its Application to Dye-sensitized Solar Cells

    Institute of Scientific and Technical Information of China (English)

    戴松元; 王孔嘉

    2003-01-01

    Properties of TiO2 nanoporous films, which are one of the crucial technologies in dye-sensitized solar cell, are investigated. The nanocrystalline TiO2 films were prepared with the sol-gel method at different pH in precursor and treatment temperature in autoclave for their application to dye-sensitized solar cells. The thickness of the TiO2 film is very important to the transfer of photoelectron as well as adsorption of dye, it is also known as one of the source to the dark current. The results show that the TiO2 films, such as different particle sizes of TiO2, different pH in precursor and treatment temperature in autoclave, have a strong influence on the photoelectrochemical properties of the dye-sensitized solar cells. We give the optimum TiO2 film thickness and morphology for the application to dye-sensitized solar cells.

  6. Photo-electrochemical properties of graphene wrapped hierarchically branched nanostructures obtained through hydrothermally transformed TiO2 nanotubes

    Science.gov (United States)

    Rambabu, Y.; Jaiswal, Manu; Roy, Somnath C.

    2017-10-01

    Hierarchically structured nanomaterials play an important role in both light absorption and separation of photo-generated charges. In the present study, hierarchically branched TiO2 nanostructures (HB-MLNTs) are obtained through hydrothermal transformation of electrochemically anodized TiO2 multi-leg nanotubes (MLNT) arrays. Photo-anodes based on HB-MLNTs demonstrated 5 fold increase in applied bias to photo-conversion efficiency (%ABPE) over that of TiO2 MLNTs without branches. Further, such nanostructures are wrapped with reduced graphene oxide (rGO) films to enhance the charge separation, which resulted in ∼6.5 times enhancement in %ABPE over that of bare MLNTs. We estimated charge transport (η tr) and charge transfer (η ct) efficiencies by analyzing the photo-current data. The ultra-fine nano branches grown on the MLNTs are effective in increasing light absorption through multiple scattering and improving charge transport/transfer efficiencies by enlarging semiconductor/electrolyte interface area. The charge transfer resistance, interfacial capacitance and electron decay time have been estimated through electrochemical impedance measurements which correlate with the results obtained from photocurrent measurements.

  7. Fabrication of Nanostructured TiO2 Using a Solvothermal Reaction for Lithium-ion Batteries

    Directory of Open Access Journals (Sweden)

    Jicai Liang

    2016-03-01

    Full Text Available Nanostructured TiO2 was successfully synthesized via a facile one-pot solvothermal reaction followed by calcina‐ tion. Hydrolysis and polycondensation of titanium butox‐ ide (Ti(OR4 were performed in the presence of sodium dodecylbenzenesulfonate (SDBS. The morphologies, crystallinity and compositions of obtained samples were identified by the methods of X-ray diffraction (XRD, Brunauer–Emmett–Teller (BET and transmission electron microscopy (TEM. It was found that the nanostructured TiO2 with an average diameter of 10±5 nm had the crystal type of anatase. A good specific surface was also obtained by the standard multipoint BET method (119.2 m2/g. As the anode materials for the lithium-ion batteries (LIBs, the anatase phase TiO2 demonstrated a relatively high gravi‐ metric specific capacity of 264.8 mAh g-1. The reversible capacity of TiO2 remained 196.4 mAh g-1 at a rate of 0.2 ̊C after 100 cycles. It indicated that this kind of TiO2 possessed a good electrochemical performance.

  8. Tailoring of antibacterial Ag nanostructures on TiO2 nanotube layers by magnetron sputtering.

    Science.gov (United States)

    Uhm, Soo-Hyuk; Song, Doo-Hoon; Kwon, Jae-Sung; Lee, Sang-Bae; Han, Jeon-Geon; Kim, Kyoung-Nam

    2014-04-01

    To reduce the incidence of postsurgical bacterial infection that may cause implantation failure at the implant-bone interface, surface treatment of titanium implants with antibiotic materials such as silver (Ag) has been proposed. The purpose of this work was to create TiO2 nanotubes using plasma electrolytic oxidation (PEO), followed by formation of an antibacterial Ag nanostructure coating on the TiO2 nanotube layer using a magnetron sputtering system. PEO was performed on commercially pure Ti sheets. The Ag nanostructure was added onto the resulting TiO2 nanotube using magnetron sputtering at varying deposition rates. Field emission scanning electron microscopy and transmission electron microscopy were used to characterize the surface, and Ag content on the TiO2 nanotube layer was analyzed by X-ray diffraction and X-ray photoelectron spectroscopy. Scanning probe microscopy for surface roughness and contact angle measurement were used to indirectly confirm enhanced TiO2 nanotube hydrophilicity. Antibacterial activity of Ag ions in solution was determined by inductively coupled plasma mass spectrometry and antibacterial testing against Staphylococcus aureus (S. aureus). In vitro, TiO2 nanotubes coated with sputtered Ag resulted in significantly reduced S. aureus. Cell viability assays showed no toxicity for the lowest sputtering time group in the osteoblastic cell line MC3T3-E1. These results suggest that a multinanostructured layer with a biocompatible TiO2 nanotube and antimicrobial Ag coating is a promising biomaterial that can be tailored with magnetron sputtering for optimal performance.

  9. Existence, release, and antibacterial actions of silver nanoparticles on Ag–PIII TiO2 films with different nanotopographies

    Directory of Open Access Journals (Sweden)

    Li J

    2014-07-01

    Full Text Available Jinhua Li, Yuqin Qiao, Hongqin Zhu, Fanhao Meng, Xuanyong Liu State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, People’s Republic of China Abstract: 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 used to estimate their antimicrobial effect. The nanostructured TiO2 films on a Ti surface exhibit a better bacteriostatic effect on both microbes compared to the pristine Ti. The nanotopographies of the TiO2 films affect the nucleation, growth, and distribution of Ag nanoparticles in the films during Ag–PIII process. The Ag nanoparticles are completely embedded into the nanorod film while partially exposed out of the nanotip and nanowire films, which account for the significant differences in the release behaviors of Ag ions in vitro. However, no significant difference exists in their antimicrobial activity against both microbes. The antimicrobial actions of the Ag@TiO2 system described here consist of two methods – the contact-killing action and the release-killing action. Nevertheless, based on the observed results, the contact-killing action should be regarded as the main method to destroy microbes for all the Ag plasma-modified TiO2 nanofilms. This study provides insight to optimize the surface design of Ti-based implants to acquire more effective antimicrobial surfaces to meet clinical applications. Keywords: silver, nanoparticles, titania, nanostructure, antibacterial, plasma

  10. Formation Mechanistism Study of TiO2 Film Comprising Nanotubes and Nanoparticles

    Science.gov (United States)

    Yang, Di; Wang, Yi-quan; Ren, Guo-bin; Feng, Shuai; Chen, Yuan-yuan; Wang, Wen-zhong

    2012-02-01

    A novel titanium dioxide (TiO2) film comprising both nanotubes and nanopaticles was fabricated by an anodization process of the modified titanium. The local electric field at the anodized surface was simulated and its influence on the morphology of the TiO2 film was discussed. The results show that the electric field strength is enhanced by the covering. The growth rate of TiO2 increases with the assist of the local electric field. However, TiO2 dissolution is hindered since the local electric field prevents [TiF6]6- from diffusing. It means that the balance condition for the formation of nanotubes is broken, and TiO2 nanoparticles are formed. Moreover, the crystal structure of the TiO2 film was confirmed using X-ray diffraction and Raman analysis. The anatase is a main phase for the proposed film.

  11. On the synthesis, characterization and photocatalytic applications of nanostructured TiO2

    Indian Academy of Sciences (India)

    P R Mishra; O N Srivastava

    2008-06-01

    Nanocrystalline semiconducting materials are attracting much attention due to their potential applications in solar energy conversion, nonlinear optics, and heterogeneous photocatalysis. In the present investigation, we have synthesized nanostructured TiO2 photocatalysts, which have been used in the photocatalytic degradation of phenol (one of the most common water pollutants). These catalysts have been prepared through sol–gel technique using titanium tetra-isopropoxide as a raw material for synthesis. Characterization techniques such as XRD, SEM and TEM have been employed for structural/microstructural investigations. XRD results show that the as synthesized TiO2 nanopowder exhibit anatase phase, TiO2. The average sizes of the TiO2 nanopowders are ∼ 5–10 nm. The optical properties of the samples were investigated through UVvisible and fluorescence techniques. It has been observed that absorption edge corresponds to ∼ 410 nm (bandgap, ∼ 3.02 eV). The emission peak in the fluorescence spectrum at ∼ 418 nm corresponds to the bandgap energy of ∼ 2.97 eV. Concentration of phenol (initial concentration, ∼ 100 ppm) with illumination time was monitored by measuring the absorbance of pure and illuminated phenol through UV-visible spectrophotometer. Salient feature of this study relates to the fact that the present sol–gel synthesized TiO2 nanopowders have been found to be better photocatalysts for phenol degradation than the presently employed commercial TiO2 (P-25, Degussa) photocatalyst. Thus, whereas phenol concentration, with the presently synthesized TiO2 nanopowders, the concentration of phenol decreases up to ∼ 32% but for commercial TiO2 nanopowder (P-25, Degussa), it decreased only up to ∼ 25%. The improved surface area is considered as an important factor for the aforesaid decrease in phenol concentration.

  12. The Growth of TiO2 Nanostructures Prepared by Anodization in Combination with Hydrothermal Method on the Ti Foil

    OpenAIRE

    Mekla Vatcharinkorn; Juisuwannathat Charuwan; Tipparach Udom

    2015-01-01

    We have investigated TiO2 nanostructures prepared by anodization in conjunction with hydrothermal method using Ti metal plates. The TiO2 nanoporus were fabricated by electrochemical anodization in a NH4F/EG4/H2O electrolyte system. Ultrasonic wave was used to clean the surface of TiO2 nanoporus in the medium of water after completing the anodization. After drying in air, the nanoporusarrays were calcined at 450 °C for 2 h in air. The TiO2 nanostructures were converted by hydrothermal in air.T...

  13. Optical absorption and electrical transport in hybrid TiO2 and polymer nanocomposite films

    Science.gov (United States)

    Zhou, Xi-Song; Li, Zheng; Wang, Ning; Lin, Yuan-Hua; Nan, Ce-Wen

    2006-06-01

    Hybrid nanofilms of poly(2-methoxy-5-ethylhexyloxy-1,4-phenylene)vinylene (MEH-PPV) and anatase-TiO2 nanoparticles were prepared. The results showed that the optical absorption spectra and electrical transport properties of the TiO2/MEH-PPV nanocomposite films were strongly dependent on the particle size and concentration of TiO2 nanoparticles in the hybrid films. In comparison with pure TiO2 nanofilms, the hybrid TiO2/MEH-PPV films presented a shift of the absorption edge to the lower-energy region, and an obvious nonlinear current-voltage characteristic.

  14. A Novel Synthesis of Two-dimensional Nanopatterned TiO2 Thin Film

    Institute of Scientific and Technical Information of China (English)

    Ming Xian LIU; Li Hua GAN; Gen CHEN; Zi Jie XU; Zhi Xian HAO; Long Wu CHEN

    2006-01-01

    A novel two-dimensional nanopatterned TiO2 thin film has been synthesized through the interaction between cationic Gemini surfactant molecules and the prepared TiO2 colloid nanoparticles with average diameters of 8 nm by controlling the surface pressure of the monolayer. TEM photographs from the formed Gemini-TiO2 composite monolayer confirm that the prepared TiO2 film is of a branch nanopattem.

  15. Photodecomposition of methylene blue by amorphous TiO2, CdS and TiO2-CdS films

    OpenAIRE

    F.G. Nieto-Caballero; E. Sánchez-Mora; J. M. Gracia-Jiménez; N.R. Silva-González; A.G. Rodríguez

    2007-01-01

    TiO2is one of the most widely studied oxide materials for applications related to photocatalytic processes. It has been reported that TiO2combined with CdS produces an improvement in the photocatalytic efficiency. This work focuses on the obtainment of TiO2, CdS and TiO2-CdSin situthin films by the sol-gel/dip coating method. After deposition on glass, each film was calcined at 300oC in an argon atmospherefor 30 min. The films were characterized by SEM, UV-Vis, XRD and micro-Raman. The TiO...

  16. Formaldehyde degradation by photocatalytic Ag-doped TiO2 film of glass fiber roving.

    Science.gov (United States)

    Ubolchonlakate, Kornkanok; Sikong, Lek; Tontai, Tienchai

    2010-11-01

    The photocatalytic Ag doped TiO2 porous films were prepared by sol-gel method and dip coated on glass fiber roving. The sol composed of titanium (IV) isopropoxide, triethanolamine, ethanol and nitric acid followed by calcination of the film at 500 degrees C for 1 hour with a heating rate of 3 degrees C/min. The surface morphology and properties of synthesized TiO2 films were characterized by X-ray diffraction, atomic forced microscope and scanning electron microscope. A laboratory photocatalytic reactor was set up to carry out photoactivity of the prepared catalysts. The results show that TiO2-Ag and TiO2-Ag-TEA porous films give highest rate of formaldehyde gas degradation. It can be noted that triethanolamine exhibits two effects on TiO2 composite films; one is its effect on porous film structure and second is a reverse effect of hindrance of anatase growth.

  17. Doped-TiO2 Photocatalysts and Synthesis Methods to Prepare TiO2 Films

    Institute of Scientific and Technical Information of China (English)

    Ying CUI; Hao DU; Lishi WEN

    2008-01-01

    TiO2 is a promising photocatalyst. However, the low photocatalytic efficiency calls for the modification of TiO2. Metal- and nonmetal-doping of TiO2 have been proved to be effective ways to enhance photocatalytic properties. This review provides a deep insight into the understanding of the metal- and nonmetal-doped TiO2 photocatalysts. This article begins with the introduction of the crystal structures of TiO2 and applications of TiO2 materials. We then reviewed the doped-TiO2 system in two categories: (1) metal-doped TiO2photocatalysts system, and (2) nonmetal-doped TiO2 photocatalysts system. Both experimental results and theoretical analyses are elaborated in this section. In the following part, for the advantages of TiO2 thin films over particles, various preparation methods to obtain TiO2 thin films are briefly discussed. Finally, this review ends with a concise conclusion and outlook of new trends in the development of TiO2-based photocatalysts.

  18. Development of visible light activated TiO2 thin films on stainless steel via sol spraying with emphasis on microstructural evolution and photocatalytic activity

    Science.gov (United States)

    Momeni, Mansour; Golestani-Fard, Farhad; Saghafian, Hasan; Barati, Nastaran; Khanahmadi, Amirhossein

    2015-12-01

    Visible light activated nitrogen doped TiO2 thin films were developed on 304 stainless steel by sol spraying method using a common painting airbrush. Thin films with different thickness were prepared and calcined at various temperatures from 400 to 600 °C. The samples were studied using ellipsometry, XRD, GIXRD, XPS, DRS, SEM and FESEM. Photocatalytic activities of the films were investigated by measuring their ability to degrade methylene blue solution under visible light irradiation. Results revealed that uniform nanostructured films with a thickness range of 29-150 nm were successfully prepared on stainless steel by sol spraying. Doping nitrogen into TiO2 structure restricted the crystallite growth of anatase phase and reduced the band gap energy to 2.85 eV and therefore, activated TiO2 in visible light region. Increasing calcination temperature not only promoted crack formation in thin films, but also encouraged Fe diffusion from substrate into thin films structure. However, the N doped TiO2 film calcined at 500 °C with a thickness of 150 nm indicated a significant photocatalytic activity in visible light with 22% higher efficiency in comparison with undoped TiO2 film. Development of TiO2 based photocatalytic thin films by a simple method of airbrushing, builds up the hope for industrial scale applications in future.

  19. Nanostructured Gd3+-TiO2 surfaces for self-cleaning application

    Science.gov (United States)

    Saif, M.; El-Molla, S. A.; Aboul-Fotouh, S. M. K.; Ibrahim, M. M.; Ismail, L. F. M.; Dahn, Douglas C.

    2014-06-01

    Preparation of self-cleaning surfaces based on lanthanide modified titanium dioxide nanoparticles has rarely been reported. In the present work, gadolinium doped titanium dioxide thin films (x mol Gd3+-TiO2 where x = 0.000, 0.005, 0.008, 0.010, 0.020 and 0.030 mol) were synthesized by sol-gel method and deposited using doctor-blade method. These films were characterized by studying their structural, optical and electrical properties. Doping with gadolinium decreases the band gap energy and increase conductivity of thin films. The photo self-cleaning activity in term of quantitative determination of the active oxidative species (rad OH) produced on the thin film surfaces was evaluated using fluorescent probe method. The results show that, the highly active thin film is the 0.020 Gd3+-TiO2. The structural, morphology, optical, electrical and photoactivity properties of Gd3+-TiO2 thin films make it promising surfaces for self-cleaning application. Mineralization of commercial textile dye (Remazol Red RB-133, RR) and durability using 0.020Gd3+-TiO2 film surface was studied.

  20. Study on UV Shielding TiO2 Thin Film Prepared by Sol-Gel Method

    Institute of Scientific and Technical Information of China (English)

    Shihai Zhao; Xiaohui Wang; Shaobo Xin; Qiang Jiang; Xiaoping Liang

    2006-01-01

    Titanium dioxide (TiO2) thin films were prepared on microscopes slides by sol-gel and dip-coating processes from specially formulated sols. The results show that there exists anatase and rutile structure of TiO2 when heat treatment temperature is 450℃, and at 800℃, TiO2 particle size is of below 100 nm and rutile structure is presented. In the range of 360 nm~400 nm the transmittance of TiO2 sol increases with the increasing of the concentration of Ti(OC4H9)4 in ethanol solution.The transmittance of TiO2 films with various number of the layer is measured to be 0% below 320 nm, and the three-layer TiO2 film is of the best UV resistance in the range of 320 nm~400 nm.

  1. 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(Ω·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.

  2. Atomic Layer Deposition TiO2 Films and TiO2/SiNx Stacks Applied for Silicon Solar Cells

    Directory of Open Access Journals (Sweden)

    Zu-Po Yang

    2016-08-01

    Full Text Available Titanium oxide (TiO2 films and TiO2/SiNx stacks have potential in surface passivation, anti-reflection coatings and carrier-selective contact layers for crystalline Si solar cells. A Si wafer, deposited with 8-nm-thick TiO2 film by atomic layer deposition, has a surface recombination velocity as low as 14.93 cm/s at the injection level of 1.0 × 1015 cm−3. However, the performance of silicon surface passivation of the deposited TiO2 film declines as its thickness increases, probably because of the stress effects, phase transformation, atomic hydrogen and thermal stability of amorphous TiO2 films. For the characterization of 66-nm-thick TiO2 film, the results of transmission electron microscopy show that the anatase TiO2 crystallinity forms close to the surface of the Si. Secondary ion mass spectrometry shows the atomic hydrogen at the interface of TiO2 and Si which serves for chemical passivation. The crystal size of anatase TiO2 and the homogeneity of TiO2 film can be deduced by the measurements of Raman spectroscopy and spectroscopic ellipsometry, respectively. For the passivating contacts of solar cells, in addition, a stack composed of 8-nm-thick TiO2 film and a plasma-enhanced chemical-vapor-deposited 72-nm-thick SiNx layer has been investigated. From the results of the measurement of the reflectivity and effective carrier lifetime, TiO2/SiNx stacks on Si wafers perform with low reflectivity and some degree of surface passivation for the Si wafer.

  3. Combination of TiO2-Film Photocatalysis and Ultrafiltration to Treat Wastewater

    Directory of Open Access Journals (Sweden)

    Shu-Hai You

    2013-01-01

    Full Text Available In this study, a combination of TiO2-film photocatalysis reactor and ultrafiltration was used treat the secondary effluent from the manufacturing of thin film transistor-liquid crystal display (TFT-LCD. TiO2 particles, as a photocatalyst, were immobilized on silica glass to form TiO2-film by the sol-gel and dip coating methods. TiO2-film photocatalysis was done within three parameters, including number of coating times of TiO2-film, wavelengths of UV light source, and operating time. During ultrafiltration, the operating pressure and feed water temperature were controlled at 300 KN/m2 and 25°C, respectively. It was found that TiO2-film photocatalysis followed by ultrafiltration increased the removal of total organic carbon (TOC to 47.13% and 49.94% for 5 KDa and 10 KDa membranes, respectively. It was also found that the process increased the permeate flux rate (ca 23% for 10 KDa membrane after 6 hours of operation, since some larger organic matter had been broken into small organic matter and some small organic matter had been mineralized into CO2 following TiO2-film photocatalysis. Therefore, combining TiO2-film photocatalysis reactor and ultrafiltration can improve organic wastewater quality and increase the permeate flux of ultrafiltration membrane, which may enhance the recycling and reuse of wastewater.

  4. Intrinsic Photocatalytic Assessment of Reactively Sputtered TiO2 Films

    NARCIS (Netherlands)

    Rafieian, Damon; Driessen, Rick T.; Ogieglo, Wojciech; Lammertink, Rob G.H.

    2015-01-01

    Thin TiO2 films were prepared by DC magnetron reactive sputtering at different oxygen partial pressures. Depending on the oxygen partial pressure during sputtering, a transition from metallic Ti to TiO2 was identified by spectroscopic ellipsometry. The crystalline nature of the film developed during

  5. Photocatalytic antibacterial performance of Sn(4+)-doped TiO(2) thin films on glass substrate.

    Science.gov (United States)

    Sayilkan, Funda; Asiltürk, Meltem; Kiraz, Nadir; Burunkaya, Esin; Arpaç, Ertuğrul; Sayilkan, Hikmet

    2009-03-15

    Pure anatase, nanosized and Sn(4+) ion doped titanium dioxide (TiO(2)) particulates (TiO(2)-Sn(4+)) were synthesized by hydrothermal process. TiO(2)-Sn(4+) was used to coat glass surfaces to investigate the photocatalytic antibacterial effect of Sn(4+) doping to TiO(2) against gram negative Escherichia coli (E. coli) and gram positive Staphylococcus aureus (S. aureus). Relationship between solid ratio of TiO(2)-Sn(4+) 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 TiO(2)-Sn(4+) is fully anatase crystalline form and easily dispersed in water. Increasing the solid ratio of TiO(2)-Sn(4+) from 10 to 50% in the coating solution increased antibacterial effect.

  6. Facile fabrication of transparent TiO2-C@TiO2-C free-standing film for visible-light photocatalytic application

    Science.gov (United States)

    Hu, Luyang; Zhang, Yumin; Zhang, Shanmei; Li, Benxia

    2017-02-01

    A transparent TiO2-C@TiO2-C free-standing film has been synthesized by two-step hydrothermal method and subsequent thermal annealing. The chemical composition and morphological features of the TiO2-C@TiO2-C film are characterized using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy and N2 adsorption-desorption measurement. The results indicate that the flower-like micro/nanostructure TiO2-C particle layers are intimately inhered to porous TiO2-C fibers. The fibers in film are interconnected each other to form a three-dimensional reticulate microstructure, and exhibit intense visible light absorption and high adsorptivity of dye molecules. The interaction between TiO2 and its surface carbon layer in TiO2-C particle promotes the generation of Ti-O-C bonds, which leads to effective charge transfer. Under visible-light irradiation, TiO2-C@TiO2-C film presents enhanced photocatalytic activity for degradation of methylene blue. This work may provide a new viewpoint for designing transparent photocatalytic film for promising applications in heterogeneous photocatalysis.

  7. Controlled preparation of porous TiO2-Ag nanostructures through supramolecular assembly for plasmon-enhanced photocatalysis.

    Science.gov (United States)

    Fei, Jinbo; Li, Junbai

    2015-01-14

    By templating Ag(+)-induced supramolecular assembly at different temperatures, porous TiO2-Ag nanotubes and nanospheres are fabricated in a controlled manner due to the effect of Rayleigh instability. Compared with traditional TiO2 nanoparticles, TiO2-Ag nanostructures above show much more extensive visible light absorption and exhibit the noticeably plasmon-enhanced photocatalysis because of the existence of Ag nanoparticles.

  8. 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.

  9. Formation of TiO2 Modified Film on Carbon Steel

    Institute of Scientific and Technical Information of China (English)

    Laizhou SONG; Shizhe SONG; Zhiming GAO

    2004-01-01

    A new technique for preparing TiO2 modified film on carbon steel was accomplished by electroless plating and sol-gel composite process. The artificial neural network was applied to optimize the preparing condition of TiO2 modified film. The optimized condition for forming TiO2 modified film on carbon steel was that NiP plating for 50 min,dip-coating times as 4, heat treatment time for 2 h, and the molar ratio of complexing agent and Ti(OC4HZ9)4 kept 1.5:1. The results showed that TiO2 modified film have good corrosion resistance. The result conformed that it is feasible to design the preparing conditions of TiO2 modified film by artificial neural network.

  10. Hydrophilic property of SiO2-TiO2 overlayer films and TiO2/SiO2 mixing films

    Institute of Scientific and Technical Information of China (English)

    关凯书; 徐宏; 吕宝君

    2004-01-01

    The photo-induced hydrophilicity of SiO2 overlayer on TiO2 films prepared by sol-gel method was investigated by means of soak angle measurement, XPS, UV-VIS and FTIR spectra. The results show that, compared with the TiO2 film without SiO2 overlayer, when the TiO2 film is thoroughly covered by SiO2 overlayer, the hydrophilicity and the sustained effect are enhanced. It is found that the significant growth of the OH group occurs in the surface of SiO2 overlayer. The different mechanism of enhanced hydrophilicity between SiO2 overlayer on TiO2 films and TiO2/SiO2 mixing films was analyzed. The result suggests that the photo-generated electrons created in the interface between TiO2 and SiO2 tend to reduce the Ti(Ⅳ) cation to the Ti(Ⅲ) state, and the photogenerated holes transmit through the SiO2 layer to uppermost surface efficiently. Once the holes go up to the surface, they tend to make the surface hydrophilic. The stable hydrophilicity of SiO2 overlayer which adsorbs more stable OH groups, enhances the sustained effect, i.e. the super-hydrophilic state can be maintained for a long time in dark place.

  11. Nanostructured TiO2 Doped with Nb as a Novel Support for PEMFC

    Directory of Open Access Journals (Sweden)

    Edgar Valenzuela

    2013-01-01

    Full Text Available Nowadays, one of the major issues of the PEMFC concerns the durability. Historically, carbon has been used as a catalyst support in PEMFC; nevertheless, under the environmental conditions of the cell, the carbon is oxidized, leaving the catalyst unsupported. In order to increase the stability and durability of the catalyst in the PEMFC, a novel nanostructured metallic oxide support is proposed. In this work, TiO2 was doped with Nb to obtain a material that combines chemical stability, high surface area, and an adequate electronic conductivity in order to be a successful catalyst support candidate for long-term PEMFC applications. The TiO2-Nb nanostructured catalyst support was physically and electrochemically characterized. According to the results, the TiO2-Nb offers high surface area and good particle dispersion; also, the electrochemical activity and stability of the support were evaluated under high potential conditions, where the TiO2-Nb proved to be much more stable than carbon.

  12. Nanostructured AgBr loaded TiO2: An efficient sunlight active photocatalyst for degradation of Reactive Red 120

    Directory of Open Access Journals (Sweden)

    Sreedhar Bojja

    2011-07-01

    Full Text Available Abstract The AgBr loaded TiO2 catalyst was prepared by a feasible approach with AgBr and tetraisopropyl orthotitanate and characterized by BET surface area measurement, diffuse reflectance spectra (DRS, scanning electron microscope (SEM, energy dispersive spectra (EDS, X-ray diffraction (XRD, transmission electron microscope (TEM and atomic force microscope (AFM analysis. The results of characterization reveal that AgBr loaded TiO2 has a nanostructure. Formation of the nanostructure in AgBr loaded TiO2 results in substantial shifting of the absorption edge of TiO2 to red and enhancement of visible light absorption. Electrochemical impedance spectroscopy measurements reveal that AgBr loaded TiO2 has a higher photoconductivity than prepared TiO2 due to higher separation efficiency of electron-hole pairs. Cyclic voltammetric studies reveal enhanced conductivity in AgBr loaded TiO2, which causes an increase in its photocatalytic activity. AgBr loaded TiO2 exhibited a higher photocatalytic activity than TiO2-P25 and prepared TiO2 in the photodegradation of Reactive Red 120 (RR 120.

  13. Well-Defined Nanostructured, Single-Crystalline TiO2 Electron Transport Layer for Efficient Planar Perovskite Solar Cells.

    Science.gov (United States)

    Choi, Jongmin; Song, Seulki; Hörantner, Maximilian T; Snaith, Henry J; Park, Taiho

    2016-06-28

    An electron transporting layer (ETL) plays an important role in extracting electrons from a perovskite layer and blocking recombination between electrons in the fluorine-doped tin oxide (FTO) and holes in the perovskite layers, especially in planar perovskite solar cells. Dense TiO2 ETLs prepared by a solution-processed spin-coating method (S-TiO2) are mainly used in devices due to their ease of fabrication. Herein, we found that fatal morphological defects at the S-TiO2 interface due to a rough FTO surface, including an irregular film thickness, discontinuous areas, and poor physical contact between the S-TiO2 and the FTO layers, were inevitable and lowered the charge transport properties through the planar perovskite solar cells. The effects of the morphological defects were mitigated in this work using a TiO2 ETL produced from sputtering and anodization. This method produced a well-defined nanostructured TiO2 ETL with an excellent transmittance, single-crystalline properties, a uniform film thickness, a large effective area, and defect-free physical contact with a rough substrate that provided outstanding electron extraction and hole blocking in a planar perovskite solar cell. In planar perovskite devices, anodized TiO2 ETL (A-TiO2) increased the power conversion efficiency by 22% (from 12.5 to 15.2%), and the stabilized maximum power output efficiency increased by 44% (from 8.9 to 12.8%) compared with S-TiO2. This work highlights the importance of the ETL geometry for maximizing device performance and provides insights into achieving ideal ETL morphologies that remedy the drawbacks observed in conventional spin-coated ETLs.

  14. On the Crystal Structural Control of Sputtered TiO2 Thin Films.

    Science.gov (United States)

    Jia, Junjun; Yamamoto, Haruka; Okajima, Toshihiro; Shigesato, Yuzo

    2016-12-01

    In this study, we focused on the origin on the selective deposition of rutile and anatase TiO2 thin films during the sputtering process. The observation on microstructural evolution of the TiO2 films by transmission electron microscopy revealed the coexistence of rutile and anatase TiO2 phases in the initial stage under the preferential growth conditions for the anatase TiO2; the observations further revealed that the anatase phase gradually dominated the crystal structure with increasing film thickness. These results suggest that the bombardment during the sputtering deposition did not obviously affect the TiO2 crystal structure, and this was also confirmed by off-axis magnetron sputtering experiments. We also investigated the mechanism of the effect of Sn impurity doping on the crystal structure using first-principles calculations. It is found that the formation energy of Sn-doped rutile TiO2 is lower than that of Sn-doped anatase TiO2; this suggests that the Sn-doped TiO2 favours the rutile phase. These results offer a guideline for the utilization of selective deposition of rutile and anatase TiO2 thin films in various industrial applications.

  15. On the Crystal Structural Control of Sputtered TiO2 Thin Films

    Science.gov (United States)

    Jia, Junjun; Yamamoto, Haruka; Okajima, Toshihiro; Shigesato, Yuzo

    2016-07-01

    In this study, we focused on the origin on the selective deposition of rutile and anatase TiO2 thin films during the sputtering process. The observation on microstructural evolution of the TiO2 films by transmission electron microscopy revealed the coexistence of rutile and anatase TiO2 phases in the initial stage under the preferential growth conditions for the anatase TiO2; the observations further revealed that the anatase phase gradually dominated the crystal structure with increasing film thickness. These results suggest that the bombardment during the sputtering deposition did not obviously affect the TiO2 crystal structure, and this was also confirmed by off-axis magnetron sputtering experiments. We also investigated the mechanism of the effect of Sn impurity doping on the crystal structure using first-principles calculations. It is found that the formation energy of Sn-doped rutile TiO2 is lower than that of Sn-doped anatase TiO2; this suggests that the Sn-doped TiO2 favours the rutile phase. These results offer a guideline for the utilization of selective deposition of rutile and anatase TiO2 thin films in various industrial applications.

  16. Antibacterial efficiencies of TiO2 nanostructured layers prepared in organic viscous electrolytes

    Science.gov (United States)

    Dumitriu, Cristina; Popescu, Marian; Ungureanu, Camelia; Pirvu, Cristian

    2015-06-01

    Using easy and cheap potential step anodization in electrolytes with different molar mass and water content, a Ti substrate was covered with a nanostructured TiO2 layer. Surface characterization of the prepared samples was conducted using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and contact angle analysis. The formation mechanism and surface morphologies are very different, depending on the molar mass and water percent of electrolyte solutions used for anodizing Ti substrate. The electrochemical behavior of the samples was studied using Tafel plots, and electrochemical impedance spectroscopy recorded in a simulated body fluid. All used anodizing treatments have conducted to samples with increased corrosion protection. The paper illustrates the antibacterial efficiencies of TiO2 nanostructured layers (shielded nanotubes, nanoporous oxide layer and some remaining PEG electrolyte) quantitatively estimated using gram-negative bacterium Escherichia coli ATCC 8738.

  17. Formation Mechanistism Study of TiO2 Film Comprising Nanotubes and Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    Di Yang; Yi-quan Wang; Guo-bin Ren; Shuai Feng; Yuan-yuan Chen; Wen-zhong Wang

    2012-01-01

    A novel titanium dioxide (TiO2) film comprising both nanotubes and nanopaticles was fabricated by an anodization process of the modified titanium.The local electric field at the anodized surface was simulated and its influence on the morphology of the TiO2 film was discussed.The results show that the electric field strength is enhanced by the covering.The growth rate of TiO2 increases with the assist of the local electric field.However,TiO2 dissolution is hindered since the local electric field prevents [TiF6]6- from diffusing.It means that the balance condition for the formation of nanotubes is broken,and TiO2 nanoparticles are formed.Moreover,the crystal structure of the TiO2 film was confirmed using X-ray diffraction and Raman analysis.The anatase is a main phase for the proposed film.

  18. Effect of Microstructure of TiO2 Thin Films on Optical Band Gap Energy

    Institute of Scientific and Technical Information of China (English)

    TIAN Guang-Lei; HE Hong-Bo; SHAO Jian-Da

    2005-01-01

    @@ TiO2 coatings are prepared on fused silica with conventional electron beam evaporation deposition. After annealed at different temperatures for four hours, the spectra and XRD patterns of TiO2 thin film are obtained. XRD patterns reveal that only anatase phase can be observed in TiO2 coatings regardless of the different annealing temperatures, and with the increasing annealing temperature, the grain size gradually increases. The relationship between the energy gap and microstructure of anatase is determined and discussed. The quantum confinement effect is observed that with the increasing grain size of TiO2 thin film, the band gap energy shifts from 3.4eV to 3.21 eV. Moreover, other possible influence of the TiO2 thin-film microstructure, such as surface roughness and thin film absorption, on band gap energy is also expected.

  19. Photocatalytic Activity of Toluene under UV-LED Light with TiO2 Thin Films

    OpenAIRE

    Thammasak Rojviroon; Apirat Laobuthee; Sanya Sirivithayapakorn

    2012-01-01

    Titanium dioxide (TiO2) and ferric-doped TiO2 (Fe-TiO2) thin films were synthesized on the surface of 304 stainless steel sheets using a simplified sol-gel preparation method. The Fe-TiO2 thin films were prepared with weight-to-volume ratios of /TiO2 of 0.3%, 0.5%, and 0.7%, respectively. The crystalline phase structures of the prepared TiO2 and Fe-TiO2 thin films were entirely anatase. The measured optical band gaps of the TiO2, 0.3% Fe-TiO2, 0.5% Fe-TiO2, and 0.7% Fe-TiO2 thin films were 3....

  20. Effect of MWCNT Inclusion in TiO2 Nanowire Array Film on the Photoelectrochemical Performance

    Institute of Scientific and Technical Information of China (English)

    Menglei Chang; Liangpeng Wu; Xinjun Li; Wei Xu

    2012-01-01

    Rutile TiO2 nanowire array films with multi-walled carbon nanotube (MWCNT) inclusion perpendicularly grown on fluorine-doped tin oxide (FTO) substrate were prepared by a facile hydrothermal method. The absorption edges of the TiO2 nanowire array films are blue-shifted with increasing MWCNT content. The resistance of the TiO2 nanowire array film is decreased by MWCNT inclusion. The optimum TiO2/MWCNT molar ratio in the feedstock is 1:0.1. For the TiO2 nanowire array film with MWCNT inclusion served as electrode in dye-sensitized solar cell (DSSC), an overall 194% increase of photoelectric conversion efficiency has been achieved.

  1. PHOTOCATALYTIC DEGRADATION OF WASTE WATER ON. THIN FILMS OF TiO2

    Institute of Scientific and Technical Information of China (English)

    Wu Zhenghuang

    2001-01-01

    The degradation of organic phosphorous pesticide waste water using thin films of TiO2, which was prepared in an atmospheric vertical chemical vapor deposition system, was studied. The results show that the wafer material for coating TiO2, the photocatalytic time, the TiO2 crystal phase, the pH value and the concentration of pesticides in waste water influence the degradation rate. These facts indicate some potential for photocatalytic treatment of waste water by utilizing sunlight.

  2. Directed synthesis of hierarchical nanostructured TiO2 catalysts and their morphology-dependent photocatalysis for phenol degradation.

    Science.gov (United States)

    Liu, Lu; Liu, Huajie; Zhao, Ya-Ping; Wang, Yuqiu; Duan, Yueqin; Gao, Guandao; Ge, Ming; Chen, Wei

    2008-04-01

    Nanostructured TiO2 with different hierarchical morphologies were synthesized via a warmly hydrothermal route. The properties of the products were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, N2 adsorption, UV-vis spectroscopy, etc. Two of the products, TiO2 1D nanorods (one-dimensional rutile TiO2 nanorods) and TiO2 3D0D microspheres (three-dimensional anatase TiO2 nanoparticle-assembled microspheres) exhibited superior photocatalytic effects on phenol degradation under UV illumination, compared with TiO2 3D1D microspheres (three-dimensional rutile TiO2 nanorods-assembled microspheres). Moreover, TiO2 3D0D was superior to TiO2 1D, as indicated by a 30% higher mineralization of dissolved phenol. Dihydroxybenze, 4,4'-dihydroxybiphenyl, benzoquinone, maleic anhydride, etc. were identified as the degradation intermediates. The excellent catalytic effect was attributed to the structural features of TiO2 1D nanorods and TiO2 3D0D microspheres, that is, a larger amount of surface active sites and a higher band gap energy resulted in more efficient decomposition of organic contaminants.

  3. Existence, release, and antibacterial actions of silver nanoparticles on Ag–PIII TiO2 films with different nanotopographies

    Science.gov (United States)

    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 used to estimate their antimicrobial effect. The nanostructured TiO2 films on a Ti surface exhibit a better bacteriostatic effect on both microbes compared to the pristine Ti. The nanotopographies of the TiO2 films affect the nucleation, growth, and distribution of Ag nanoparticles in the films during Ag–PIII process. The Ag nanoparticles are completely embedded into the nanorod film while partially exposed out of the nanotip and nanowire films, which account for the significant differences in the release behaviors of Ag ions in vitro. However, no significant difference exists in their antimicrobial activity against both microbes. The antimicrobial actions of the Ag@TiO2 system described here consist of two methods – the contact-killing action and the release-killing action. Nevertheless, based on the observed results, the contact-killing action should be regarded as the main method to destroy microbes for all the Ag plasma-modified TiO2 nanofilms. This study provides insight to optimize the surface design of Ti-based implants to acquire more effective antimicrobial surfaces to meet clinical applications. PMID:25075186

  4. Positive role of incorporating P-25 TiO2 to mesoporous-assembled TiO2 thin films for improving photocatalytic dye degradation efficiency.

    Science.gov (United States)

    Sreethawong, Thammanoon; Ngamsinlapasathian, Supachai; Yoshikawa, Susumu

    2014-09-15

    In this work, a simple and effective strategy to improve the photocatalytic dye degradation efficiency of the mesoporous-assembled TiO2 nanoparticle thin films by incorporating small contents of commercial P-25 TiO2 during the thin film preparation was developed. The mesoporous-assembled TiO2 nanoparticles were synthesized by a sol-gel method with the aid of a mesopore-directing surfactant, followed by homogeneously mixing with P-25 TiO2 prior to the thin film coating on glass substrate. The mesoporous-assembled TiO2 film with 5 wt.% P-25 TiO2 incorporation and calcined at 400°C provided an improved photocatalytic Acid Black (AB) dye degradation efficiency. The increase in number of coated layers to the optimum four layers of the aforementioned film was found to further improve the degradation efficiency. The recyclability test of this 5 wt.% P-25 TiO2-incorporated mesoporous-assembled TiO2 film with four coated layers revealed that it can be reused for multiple cycles without a requirement of post-treatment while the degradation efficiency was retained.

  5. Double-sided brush-shaped TiO2 nanostructure assemblies with highly ordered nanowires for dye-sensitized solar cells.

    Science.gov (United States)

    Zha, Chenyang; Shen, Liming; Zhang, Xiaoyan; Wang, Yifeng; Korgel, Brian A; Gupta, Arunava; Bao, Ningzhong

    2014-01-08

    We describe a seeded hydrothermal process for the growth of unique double-sided brush-shaped (DSBS) TiO2 nanostructure assemblies consisting of highly ordered rutile nanowires vertically aligned around an annealed TiO2 nanoparticle layer. The annealed TiO2 nanoparticle layer seeds the nanowire growth and also supports the DSBS structure. The morphology of the DSBS TiO2 nanostructure depends on the hydrothermal reaction time. The diameter of the nanowires is about 6.6 nm, and with increasing reaction time from 1 to 8 h the nanowire length increases from 0.6 to 6.2 μm, whereas the thickness of the nanoparticle layer decreases from 4.3 to 2.8 μm. These free-standing nanowire arrays provide large internal surface area, which is essential for minimizing carrier recombination in high performance photovoltaic devices. Furthermore, the nanowire architecture can help increase the rate of charge transport as compared to particulate films because of lower concentration of grain boundaries. The power conversion efficiency of backside (DSBS TiO2/FTO photoanode) illuminated dye-sensitized solar cells fabricated using the DSBS TiO2 nanostructure assembly is found to be depended on the nanowire length. A cell fabricated using 15.2 μm thick nanostructures sensitized by N719 has a short-circuit current density of 12.18 mA cm(-2), 0.78 V open circuit potential, and a 0.59 filling factor, yielding a maximum power conversion efficiency of 5.61% under AM 1.5 illumination.

  6. Photocatalytic activity of porous TiO2 films prepared by anodic oxidation

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; TAO Jie; WANG Tao; WANG Ling

    2007-01-01

    Anatase titanium dioxide is an active photocatalyst, however, it is difficult to be immobilized on the substrate.The crystalline TiO2 porous film was prepared directly on the surface of pure titanium by anodic oxidation. The film was then used for photocatalysis via the methyl orange degradation method. The effects of anodization voltage, pH value, TiO2 film area and degradation time on the photocatalyst were investigated respectively by UV-visible spectrum. It was indicated that the TiO2 film prepared by anodic oxidation at 140 V had the best photocatalysis capability and the degradation of methyl orange was accelerated with acid addition.

  7. Porous Anatase TiO2 Thin Films for NH3 Vapour Sensing

    Science.gov (United States)

    Ponnusamy, Dhivya; Madanagurusamy, Sridharan

    2015-12-01

    Anatase titanium dioxide (TiO2) thin films were deposited onto cleaned glass substrates by a direct current (DC) reactive magnetron sputtering technique for different deposition times from 10 min to 40 min, which resulted in films of different thicknesses. Characterization techniques, such as x-ray diffraction (XRD) and field emission-scanning electron microscopy (FE-SEM) were used to characterize the structural and morphological properties of the TiO2 thin films. XRD patterns showed the formation of (101) crystal anatase facets. The grain size values of the film increased with increased deposition time, and the films deposited at 40 min exhibited a porous structure. Anatase TiO2 thin films exhibited excellent sensing response, fast response and recovery time, as well as good stability and selectivity towards ammonia (NH3). The enhanced NH3 sensing behavior of anatase TiO2 films is attributed to the porous morphology and oxygen vacancies.

  8. In-situ preparation of hierarchical flower-like TiO2/carbon nanostructures as fillers for polymer composites with enhanced dielectric properties

    Science.gov (United States)

    Xu, Nuoxin; Zhang, Qilong; Yang, Hui; Xia, Yuting; Jiang, Yongchang

    2017-01-01

    Novel three-dimensional hierarchical flower-like TiO2/carbon (TiO2/C) nanostructures were in-situ synthesized via a solvothermal method involving calcination of organic precursor under inert atmosphere. The composite films comprised of P (VDF-HFP) and as-prepared hierarchical flower-like TiO2/C were fabricated by a solution casting and hot-pressing approach. The results reveal that loading the fillers with a small amount of carbon is an effective way to improve the dielectric constant and suppress the dielectric loss. In addition, TiO2/C particles with higher carbon contents exhibit superiority in promoting the dielectric constants of composites when compared with their noncarbon counterparts. For instance, the highest dielectric constant (330.6) of the TiO2/C composites is 10 times over that of noncarbon-TiO2-filled ones at the same filler volume fraction, and 32 times over that of pristine P (VDF-HFP). The enhancement in the dielectric constant can be attributed to the formation of a large network, which is composed of local micro-capacitors with carbon particles as electrodes and TiO2 as the dielectric in between. PMID:28262766

  9. In-situ preparation of hierarchical flower-like TiO2/carbon nanostructures as fillers for polymer composites with enhanced dielectric properties

    Science.gov (United States)

    Xu, Nuoxin; Zhang, Qilong; Yang, Hui; Xia, Yuting; Jiang, Yongchang

    2017-03-01

    Novel three-dimensional hierarchical flower-like TiO2/carbon (TiO2/C) nanostructures were in-situ synthesized via a solvothermal method involving calcination of organic precursor under inert atmosphere. The composite films comprised of P (VDF-HFP) and as-prepared hierarchical flower-like TiO2/C were fabricated by a solution casting and hot-pressing approach. The results reveal that loading the fillers with a small amount of carbon is an effective way to improve the dielectric constant and suppress the dielectric loss. In addition, TiO2/C particles with higher carbon contents exhibit superiority in promoting the dielectric constants of composites when compared with their noncarbon counterparts. For instance, the highest dielectric constant (330.6) of the TiO2/C composites is 10 times over that of noncarbon-TiO2-filled ones at the same filler volume fraction, and 32 times over that of pristine P (VDF-HFP). The enhancement in the dielectric constant can be attributed to the formation of a large network, which is composed of local micro-capacitors with carbon particles as electrodes and TiO2 as the dielectric in between.

  10. Understanding the Role of Dynamic Wettability for Condensate Microdrop Self-Propelling Based on Designed Superhydrophobic TiO2 Nanostructures.

    Science.gov (United States)

    Zhang, Songnan; Huang, Jianying; Tang, Yuxin; Li, Shuhui; Ge, Mingzheng; Chen, Zhong; Zhang, Keqin; Lai, Yuekun

    2017-01-01

    The ability to release the adhered drops on superhydrophobic surfaces is very important for self-cleaning, antifrosting/icing, microfluidic device, and heat transfer applications. In this paper, three types of in situ electrochemical anodizing TiO2 nanostructure films are rationally designed and fabricated on titanium substrates with special superwettability, viz., TiO2 nanotube arrays, irregular TiO2 nanotube arrays, and hierarchical TiO2 particle arrays (HTPA), and their corresponding behavior in condensate microdrop self-propelling (CMDSP) is investigated. Compared to the flat titanium counterpart, all three types of rough TiO2 samples demonstrate a uniform distribution of smaller microscale droplets. Among the treated surfaces, the HTPA possesses the highest condensate density, and more than 80% of the droplets possess a diameter below 10 μm. Theoretical analysis indicates that the feature is mainly due to the morphology and structure induced extremely low droplet adhesion on super-antiwetting TiO2 hierarchical surfaces, where the excess surface energy released from the migration leads to the self-propelling of merged microdrop. This work offers a way to rationally construct CMDSP surfaces with excellent self-cleaning, antifrosting/icing ability, and enhanced condensation heat transfer efficiency.

  11. Preparation of Nanometer-structured TiO2 Thin Films by Sol-Gel Method

    Institute of Scientific and Technical Information of China (English)

    HE Feng; LI Qian-tao; HU Wang-kai; DENG Tao

    2002-01-01

    The transparent anatase TiO2 nanometer thin films were prepared by the sol-gel method on soda-lime glass. X-ray diffraction, thermal analysis and UV-visible spectrophotometer were used to analyze the formation of the phases. Only increasing the heat-treatment time, the average grain size has no obvious change. The mechanism of grain growth in TiO2 thin film is probably as follows: the grain of coating will become grain core later; TiO2 sol constantly deposited on the surface of TiO2 grain and formed membrane with increasing of coating cycle times; TiO2 grain in the film grow steadily.

  12. Recent progress in design, synthesis, and applications of one-dimensional TiO2 nanostructured surface heterostructures: a review.

    Science.gov (United States)

    Tian, Jian; Zhao, Zhenhuan; Kumar, Anil; Boughton, Robert I; Liu, Hong

    2014-01-01

    One-dimensional TiO2 nanostructured surface heterostructures (1D TiO2NSHs) have been comprehensively studied during the past two decades because of the possible practical applications in various fields, including photocatalysis, dye-sensitized solar cells, sensors, lithium batteries, biomedicine, catalysis, and supercapacitors. Combining extensive advancements in materials science and nanotechnology, a 1D TiO2NSH material with well-controlled size, morphology, and composition has been designed and synthesized. More importantly, its superior properties, including a high aspect ratio structure, chemical stability, large specific surface area, excellent electronic or ionic charge transfer, and a specific interface effect, have attracted a great deal of interest in improving current performance and exploring new applications. In this tutorial review, we introduce the characteristics of 1D TiO2 nanostructures, the design principles for the fabrication of 1D TiO2NSHs, and we also summarize the recent progress in developing synthesis methods and applications of 1D TiO2NSHs in different fields. The relationship between the secondary phase and the 1D TiO2 nanostructure and between the performance in applications and the excellent physical properties of 1D TiO2NSHs are also discussed.

  13. Photoelectrochemical Behavior of 3d Transition Metal Nanostructured film Electrode Doped with TiO2%3d过渡金属掺杂TiO2纳米晶膜电极的光电化学研究

    Institute of Scientific and Technical Information of China (English)

    李卫华; 乔学斌; 高恩勤; 杨迈之; 郝彦忠; 蔡生民

    2000-01-01

    应用原子力显微镜和x射线粉末法对3d过渡金属离子Cr(Ⅲ),Fe(Ⅲ),Mn(Ⅱ),Co(Ⅱ),Ni(Ⅱ),Cu(Ⅱ)和Zn(Ⅱ)掺杂TiO2纳米晶粒(简写为M3d-TiO2)作了表征,并用光电化学方法研究了M3d-TiO2纳米结构多孔膜电极.实验结果表明,M3d-TiO2纳米粒子的颗粒较均匀,粒径约为15 nm,其晶型为锐钛矿和板钛矿的混晶.在所研究的M3d-TiO2中,只有Zn2+-TiO2电极的光电流大于未掺杂的TiO2纳米结构多孔膜电极.3d金属离子的掺杂引起各电极的光电流信号在一定波长范围内出现p-n转型现象.%The 3d transition metal ions [Cr(Ⅲ), Fe(Ⅲ), Mn (Ⅱ), Co(Ⅱ), Ni(Ⅱ), Cu(Ⅱ), Zn(Ⅱ)]nanocrystalline doped with TiO2(abbr. M3d-TiO2) were characterized by AFM and XRD. The M3d-TiO2 nanostructured film electroede was prepared and investigated with photoelectrochemical techniques. The results show that the size of M~-TiO2 nanocrystalline particles was quite uniform and the radii were about 15 nm. The M3d-TiO2 nanocrystalline particles were a mixture of brookite and anatase crystal forms. Of all the M3D-TiO2 investigated in this paper, however, the photocurrent intensity of Zn2+-TiO2 nanostructured film electode was higher than that of the electrode undoped with TiO2. The phenomenon of p-n type inversion was observed in certain wavelength range, which was caused by 3d transition ions doping.

  14. Low-Temperature Electrostatic Self-Assembly of Noble Metals on TiO2 Nanostructured Films with Enhanced Photocatalytic Activity%低温静电自组装法制备贵金属修饰TiO2纳米结构薄膜及其增强的光催化性能

    Institute of Scientific and Technical Information of China (English)

    傅平丰; 张彭义

    2014-01-01

    Photoactive TiO2 nanostructured films (i.e., nanoflowers and nanowires) have been directly synthesized on Ti sheets using an alkali-hydrothermal route. Ultrafine noble metals (i.e., Au, Pt, Pd) nanoparticles (NPs) were homogenously dispersed onto the TiO2 nanostructures using a facile low temperature electrostatic self-assembly approach. The resulting noble-metal/TiO2-nanostructured films supported on Ti sheets had an al -in-one structure with al of the virtues of a porous framework and enhanced photocatalytic activity. Ultra high-resolution field-emission scanning electron microscopy (FESEM) revealed that the noble metal NPs were uniformly dispersed on the TiO2 surface with good physical separation properties. The average sizes of the loaded Au, Pt, and Pd NPs were approximately 4.0, 2.0, and 10.0 nm, respectively. Noble metal NPs were deposited not only on the film surface but also in the interior framework of the TiO2 films with a depth of more than 580 nm, as revealed by Auger electron spectroscopic (AES) in-depth profiling analysis. X-ray photoelectron spectroscopy (XPS) analysis revealed that the Pt and Pd NPs had been partial y oxidized to PtOabs and immobicompletely oxidized to PdO, respectively, whereas the Au NPs remained in a metallic state after being annealed in air at 300 °C. During the electrostatic self-assembly process, the loading of the noble metal can be adjusted by controlling the assembly time and the colloidal pH value. The degradation of aqueous methyl orange showed that the Au/TiO2 (or Pt/TiO2)-nanostructured films possessed remarkably enhanced photocatalytic activity compared with pure TiO2 films, and revealed that the metal NPs played a positive role in separating photogenerated hole-electron pairs. However, the deposited PdO species had no discernible impact on the activity of the TiO2 nanostructures.%以碱-水热法在金属Ti片上原位生长了TiO2纳米结构(纳米花和纳米线)薄膜,并采用低温静电自组装方法将超

  15. Synthesis of iron(Ⅲ)-doped nanostructure TiO2/SiO2 and their photocatalytic activity

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Iron(Ⅲ)-doped nanostructure TiO2-coated SiO2 (TiO2/SiO2) particles were prepared using the layer-by-layer assembly technique and their photocatalytic property was studied. TiO2 colloids were synthesized employing the sol-gel method with TiCl4 as a precursor. The samples were characterized by Fourier transform infrared spectroscopy (FTIR), SEM, EDS, XPS, and XRD. The experimental results show that TiO2 nanopowders on the surface of SiO2 particles are well distributed, the amount of TiO2 is increased with the adding of coating layers, the pure anatase-TiO2 coating layers are synthesized at 500℃, and the photocatalytic activity of Fe3+-doped TiO/SiO2 is higher than tnat of undoped TiO2/SiO2.

  16. Visible light degradation of textile effluent using nanostructured TiO2/Ag/CuO photocatalysts

    OpenAIRE

    Karthikeyan, N.; Narayanan, V.; Stephen, A

    2016-01-01

    TiO2, Ag and CuO nanomaterials, and nanostructured TiO2/Ag/CuO photocatalytic materials coupled in different weight percentages were synthesized. The prepared materials were characterized by XRD, SEM, EDX and UV-Vis diffuse reflectance spectroscopy. Photocatalytic degrading capabilities of the pure, as well as the nanostructured TiO2/Ag/CuO photocatalytic materials were tested on the dye effluent collected from the textile industries. The samples collected during the photocatalytic degradatio...

  17. Photocatalytic Degradation of Mecoprop and Clopyralid in Aqueous Suspensions of Nanostructured N-doped TiO2

    Directory of Open Access Journals (Sweden)

    Tatiana Giannakopoulou

    2010-04-01

    Full Text Available The work describes a study of the oxidation power of N-doped and undoped anatase TiO2, as well as TiO2 Degussa P25 suspensions for photocatalytic degradation of the herbicides RS-2-(4-chloro-o-tolyloxypropionic acid (mecoprop and 3,6-dichloro-pyridine-2-carboxylic acid (clopyralid using visible and UV light. Undoped nanostructured TiO2 powder in the form of anatase was prepared by a sol-gel route. The synthesized TiO2, as well as TiO2 Degussa P25 powder, were modified with urea to introduce nitrogen into the structure. N-doped TiO2 appeared to be somewhat more efficient than the starting TiO2 (anatase powder when visible light was used for mecoprop degradation. N-doped TiO2 Degussa P25 was also slightly more efficient than TiO2 Degussa P25. However, under the same experimental conditions, no degradation of clopyralid was observed in the presence of any of the mentioned catalysts. When the kinetics of mecoprop degradation was studied using UV light, more efficient were the undoped powders, while in the case of clopyralid, N-doped TiO2 Degussa P25 powder was most efficient, which is probably a consequence of the difference in the molecular structure of the two herbicides.

  18. Photoinduced underwater superoleophobicity of TiO2 thin films.

    Science.gov (United States)

    Sawai, Yusuke; Nishimoto, Shunsuke; Kameshima, Yoshikazu; Fujii, Eiji; Miyake, Michihiro

    2013-06-11

    The photoinduced wettabilities of water, n-hexadecane, dodecane, and n-heptane on a flat TiO2 surface prepared by a sol-gel method-based coating were investigated. An amphiphilic surface produced by UV irradiation exhibited underwater superoleophobicity with an extremely high static oil contact angle (CA) of over 160°. The TiO2 surface almost completely repelled the oil droplet in water. A robust TiO2 surface with no fragile nanomicrostructure was fabricated on a Ti mesh with a pore size of approximately 150 μm. The fabricated mesh was found to be applicable as an oil/water separation filter.

  19. Variation of Photocatalytic Function of TiO2 Film by Femtosecond Laser Irradiation

    Science.gov (United States)

    Tsukamoto, Masahiro; Shinonaga, Togo; Horiguchi, Naoto; Yoshida, Minoru; Fujita, Masayuki; Abe, Nobuyuki

    Titanium dioxide (TiO2) is functional ceramics and shows the photocatalytic function by ultraviolet light illumination. This photocatalytic function enables decomposition of organic matter such as bacteria, mold and odors. In our previous study, the TiO2 film was darkened by the femtosecond laser irradiation and electrical resistance of the darkened film was decreased. In this study, we investigated variation of the photocatalytic function of the darkened TiO2 films. The TiO2 film was produced by aerosol beam irradiation. The wavelength, the pulse width and the repetition rate of the femtosecond laser were 775 nm, 150 fs and 1 kHz, respectively. The laser spot was scanned on the whole area of the TiO2 film surface and the laser fluence was changed within the laser fluence regime in which the laser ablation was not caused and topography of the film surface was not varied. The photocatalytic function of the darkened TiO2 films was evaluated in the acetaldehyde decomposition test. In the test, the films in acetaldehyde were illuminated with the UV and visible light sources, respectively. The acetaldehyde concentration was measured every hour during the illumination. The results of the test shows that the film had photocatalytic function by visible light illumination.

  20. 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.

  1. Deposition of Co-doped TiO2 Thin Films by sol-gel method

    Science.gov (United States)

    Boutlala, A.; Bourfaa, F.; Mahtili, M.; Bouaballou, A.

    2016-03-01

    Cobalt doped TiO2 thin films have been prepared by sol-gel method onto glass substrate at room temperature. in this present work, we are interesting to study the effect of Cobalt doped TiO2 thin films.the concentration of Co was varied from 0 to 6%at .The obtained films have been annealed at 500°C for 2 hours. X-ray diffraction patterns showed that Co: TiO2 films are polycrystalline with a tetragonal anatase and orthorhombic brookite types structures. The surface morphologies of the TiO2 doped with cobalt thin films were evaluated by Atomic Force Microscopy (AFM). The optical properties were studied by mean of UV-visible and near infrared spectroscopy.The calculated optical band gap decreases from 3.30 to 2.96 eV with increasing Co doping.

  2. Photoelectrochemical activity of liquid phase deposited TiO2 film for degradation of benzotriazole.

    Science.gov (United States)

    Ding, Yaobin; Yang, Changzhu; Zhu, Lihua; Zhang, Jingdong

    2010-03-15

    TiO(2) film deposited on glassy carbon electrode surface was prepared via the liquid phase deposition (LPD). The deposited TiO(2) 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 TiO(2) 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 TiO(2) 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.

  3. Nanocrystalline Pt-doped TiO2 thin films prepared by spray pyrolysis for hydrogen gas detection

    Indian Academy of Sciences (India)

    Lalchand A Patil; Dinesh N Suryawanshi; Idris G Pathan; Dhanashri G Patil

    2014-05-01

    Nanostructured pure and Pt-doped TiO2 thin films were prepared by chemical spray pyrolysis technique. Aqueous solution of TiCl3.6H2O (0.01 M) was chosen as the starting solution for the preparation of pure TiO2 thin film. Aqueous solutions of PtCl6.6H2O (0.01 M) and TiCl3.6H2O (0.01 M) were mixed in volume % of 1 : 99, 2.5 : 97.5 and 5 : 95 respectively to obtain Pt-doped TiO2 thin films. The solutions were sprayed onto quartz substrate heated at 350 °C temperature to obtain the films. These thin films were fired for one hour at 550 °C. The sensing performance of these films was tested for various gases such as LPG, H2, CO2, ethanol, NH3 and Cl2 (1000 ppm). The Pt-doped TiO2 (1 : 99) was observed to be most sensitive (572) to H2 at 400 °C with high selectivity against other gases. Its response time was short (10 s) and recovery was also fast (14 s). To understand the reasons behind the gas-sensing performance of the films, their structural and micro-structral properties were studied using X-ray diffraction and electron microscopy (FE–SEM and TEM), respectively. Thicknesses of all these samples were determined using Surface Profiler. The results are interpreted.

  4. Ultraviolet emission enhancement in ZnO thin films modified by nanocrystalline TiO2

    Science.gov (United States)

    Zheng, Gaige; Lu, Xi; Qian, Liming; Xian, Fenglin

    2017-05-01

    In this study, nanocrystalline TiO2 modified ZnO thin films were prepared by electron beam evaporation. The structural, morphological and optical properties of the samples were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), UV-visible spectroscopy, fluorescence spectroscopy, respectively. The composition of the films was examined by energy dispersive X-ray spectroscopy (EDX). The photoluminescent spectrum shows that the pure ZnO thin film exhibits an ultraviolet (UV) emission peak and a strong green emission band. Surface analysis indicates that the ZnO thin film contains many oxygen vacancy defects on the surface. After the ZnO thin film is modified by the nanocrystalline TiO2 layer, the UV emission of ZnO is largely enhanced and the green emission is greatly suppressed, which suggests that the surface defects such as oxygen vacancies are passivated by the TiO2 capping layer. As for the UV emission enhancement of the ZnO thin film, the optimized thickness of the TiO2 capping layer is ∼16 nm. When the thickness is larger than 16 nm, the UV emission of the ZnO thin film will decrease because the TiO2 capping layer absorbs most of the excitation energy. The UV emission enhancement in the nanocrystalline TiO2 modified ZnO thin film can be attributed to surface passivation and flat band effect.

  5. NANOSTRUCTURED TiO2 SENSITIZED WITH PORPHYRINS FOR SOLAR WATER-SPLITTING

    Directory of Open Access Journals (Sweden)

    MARCELA-CORINA ROŞU

    2011-03-01

    Full Text Available Nanostructured TiO2 sensitized with porphyrins for Solar water-splitting.The production of hydrogen from water using solar light is very promising for generations of an ecologically pure carrier contributing to a clean, sustainable and renewable energy system. The selection of specific photocatalyst material for hydrogen production in photoelectrochemical cells (PECs is based on some important characteristics of semiconductor, such as photo-corrosion and chemical corrosion stability, photocatalytic potential, high sensitivity for UV-visible light. In the present paper, different nanocrystalline TiO2 photoanodes have been prepared via wet-chemical techniques followed by annealing treatment and sensitized with porphyrins and supramolecular complexes of porphyrins. The so obtained photocatalysts were characterized with UV-VIS absorption spectroscopy and spectrofluorimetry. The purpose of these experiments is to show if the prepared materials possess the necessary photocatalytic characteristics and if they can be used with success in H2 production from water decomposition in PECs.

  6. Characterization of Sol-gel-derived TiO2 and TiO2-SiO2 Films for Biomedical Applications

    Institute of Scientific and Technical Information of China (English)

    Jingxiao LIU; Fei SHI; Dazhi YANG

    2004-01-01

    In order to improve the corrosion resistance and biocompatibility of NiTi surgical alloy, TiO2 and TiO2-SiO2 thin films were prepared by sol-gel method. The surface characteristics of the film, which include surface composition, microstructure and surface morphology, were studied by X-ray diffraction (XRD), atomic force microscopy (AFM) and X-ray photoelectron spectra (XPS), respectively. A scratching test was used to assess the interface adhesive strength between the film and substrate. The corrosion resistance of NiTi alloy coated with oxide films were studied by anodic polarization curves measurement in biological solution. Additionally, a preliminary study of the in vitro bioactivity of the films was conducted. The results indicated that TiO2 and TiO2-SiO2 (Ti/Si=4:1) films have higher electrochemical corrosion resistance and can be used as protective layers on NiTi alloy. In addition, TiO2-SiO2 composite films have better bioactivity than TiO2 film.

  7. TiO2-BASED Composite Films for the Photodegradation of Oxytetracycline

    Science.gov (United States)

    Li, Hui; Guan, Ling-Xiao; Feng, Ji-Jun; Li, Fang; Yao, Ming-Ming

    2015-02-01

    The spread of the antibiotic oxytetracycline (OTC) has been thought as a threat to the safety of drinking water. In this paper, the photocatalytic activity of the nanocrystalline Fe/Ca co-doped TiO2-SiO2 composite film for the degradation of OTC was studied. The films were characterized by field emission scanning electron microscopy (FE-SEM) equipped with energy-dispersive spectroscopy (EDS), N2 adsorption/desorption isotherms, photoluminescence (PL) spectra, and UV-Vis diffraction reflectance absorption spectra (DRS). The FE-SEM results indicated that the Fe/Ca co-doped TiO2-SiO2 film was composed of smaller nanoparticles compared to pure TiO2 or TiO2-SiO2 film. The BET surface area results showed that the specific surface area of the pure TiO2, TiO2-SiO2 and Ca2+/Fe3+ co-doped TiO2-SiO2 is 118.3 m2g-1, 294.3 m2g-1 and 393.7 m2g-1, respectively. The DRS and PL spectra revealed that the Fe/Ca co-doped TiO2-SiO2 film had strong visible light adsorption and diminished electrons/holes recombination. Experimental results showed that the Fe/Ca co-doped TiO2-SiO2 film is effective in the degradation of OTC under both UV and visible light irradiation.

  8. Use of co-spray pyrolysis for synthesizing nitrogen-doped TiO2 films

    Indian Academy of Sciences (India)

    Nho Pham Van; Pham Hoang Ngan

    2013-10-01

    Nitrogen-doped nanocrystalline TiO2 is well known as the most promising photocatalyst. Despite many years after discovery, seeking of efficient method to prepare TiO2 doped with nitrogen still attracts a lot of attention. In this paper, we present the result of using co-spray pyrolysis to synthesize nitrogen-doped TiO2 films from TiCl4 and NH4NO3. The grown films were subjected to XRD, SEM, photocatalysis, absorption spectra and visible-light photovoltaic investigations. All the deposited films were of nanosized polycrystal, high crystallinity, pure anatase and porosity. Specific characteristics involved nitrogen doping such as enhanced photocatalytic activity, bandgap narrowing, visible light responsibility and typical correlation of the photoactivity with nitrogen concentration were all exhibited. Obtained results proved that high photoactive nitrogen-doped TiO2 films can be synthesized by co-spray pyrolysis.

  9. The properties of transparent TiO2 films for Schottky photodetector

    Directory of Open Access Journals (Sweden)

    Sung-Ho Park

    2017-08-01

    Full Text Available In this data, the properties of transparent TiO2 film for Schottky photodetector are presented for the research article, entitled as “High-performing transparent photodetectors based on Schottky contacts” (Patel et al., 2017 [1]. The transparent photoelectric device was demonstrated by using various Schottky metals, such as Cu, Mo and Ni. This article mainly shows the optical transmittance of the Ni-transparent Schottky photodetector, analyzed by the energy dispersive spectroscopy and interfacial TEM images for transparency to observe the interface between NiO and TiO2 film. The observation and analyses clearly show that no pinhole formation in the TiO2 film by Ni diffusion. The rapid thermal process is an effective way to form the quality TiO2 film formation without degradation, such as pinholes (Qiu et al., 2015 [2]. This thermal process may apply to form functional metal oxide layers for solar cells and photodetectors.

  10. Superhydrophilic graphene-loaded TiO2 thin film for self-cleaning applications.

    Science.gov (United States)

    Anandan, Srinivasan; Rao, Tata Narasinga; Sathish, Marappan; Rangappa, Dinesh; Honma, Itaru; Miyauchi, Masahiro

    2013-01-01

    We develop a simple approach to fabricate graphene-loaded TiO(2) thin films on glass substrates by the spin-coating technique. Our graphene-loaded TiO(2) films were highly conductive and transparent and showed enhanced photocatalytic activities. More significantly, graphene/TiO(2) films displayed superhydrophilicity within a short time even under a white fluorescent light bulb, as compared to a pure TiO(2) film. The enhanced photocatalytic activity of graphene/TiO(2) films is attributed to its efficient charge separation, owing to electrons injection from the conduction band of TiO(2) to graphene. The electroconductivity of the graphene-loaded TiO(2) thin film also contributes to the self-cleaning function by its antifouling effect against particulate contaminants. The present study reveals the ability of graphene as a low cost cocatalyst instead of expensive noble metals (Pt, Pd), and further shows its capability for the application of self-cleaning coatings with transparency. The promising characteristics of (inexpensive, transparent, conductive, superhydrophilic, and highly photocatalytically active) graphene-loaded TiO(2) films may have the potential use in various indoor applications.

  11. Correlation of Photocatalysis and Photoluminescence Effect in Relation to the Surface Properties of TiO2:Tb Thin Films

    OpenAIRE

    Damian Wojcieszak; Danuta Kaczmarek; Jaroslaw Domaradzki; Michal Mazur

    2013-01-01

    In this paper structural, optical, photoluminescence, and photocatalytic properties of TiO2 and TiO2:(2.6 at. % Tb) thin films have been compared. Thin films were prepared by high-energy reactive magnetron sputtering process, which enables obtaining highly nanocrystalline rutile structure of deposited films. Crystallites sizes were 8.7 nm and 6.6 nm for TiO2 and TiO2:Tb, respectively. Surface of prepared thin films was homogenous with small roughness of ca. 7.2 and 2.1 nm in case of TiO2 and ...

  12. Interstitial Boron-Doped TiO2 Thin Films: The Significant Effect of Boron on TiO2 Coatings Grown by Atmospheric Pressure Chemical Vapor Deposition.

    Science.gov (United States)

    Quesada-González, Miguel; Boscher, Nicolas D; Carmalt, Claire J; Parkin, Ivan P

    2016-09-28

    The work presented here describes the preparation of transparent interstitial boron-doped TiO2 thin-films by atmospheric pressure chemical vapor deposition (APCVD). The interstitial boron-doping, on TiO2, proved by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), is shown to enhance the crystallinity and significantly improve the photocatalytic activity of the TiO2 films. The synthesis, highly suitable for a reel-to-reel process, has been carried out in one step.

  13. Understanding the effect of flower extracts on the photoconducting properties of nanostructured TiO2.

    Science.gov (United States)

    Ansari, S G; Bhayana, Laitka; Umar, Ahmad; Al-Hajry, A; Al-Deyab, Salem S; Ansari, Z A

    2012-10-01

    Here we report an easy method to improve the optoelectronic properties of commercially available TiO2 nanopowder using extracts of various flowers viz. Calendula Orange (CO), Calendula Yellow (CY), Dahlia Violet (DV), Dahlia Yellow (DY), Rabbit flower (RF), Sweet Poppy (SP), Sweet Williams (SW) and their Mixed Extracts (ME). Various analysis techniques such as UV-Vis, FTIR, FESEM, XRD, and Raman spectroscopy were used to characterize for elemental, structural and morphological properties of the unmixed/mixed TiO2 nanopowder. TiO2 nanopowder was also calcined at 550 degrees C. Thick films of the these unmixed/mixed powder were printed, using conventional screen printing method, on fluorine doped tin oxide (FTO) substrate with organic binders and dried at 45 degrees C. The photoconducting properties are investigated as a function of wavelength from ultra-violet (UV) to infra-red (IR) region at a constant illumination intensity. Photocurrent gradually decreases when irradiated from UV to IR region. In case of unmixed and uncalcined TiO2, conductance decreased continuously whereas when extracts are added, a flat region of conductance is observed. The overall effect of extracts (colour pigments) is seen as an increase in the photoconductance. Highest photoconductance is observed in case of DY flower extract. Anthocyanins, present in flowers are known to have antioxidative properties and hence can contribute in photoconduction by reducing the surface adsorbed oxygen. This investigation indicates the potential use of flower extracts for dye sensitized solar cell (DSSC).

  14. Grain Size and Wettability of TiO2/SiO2 Photocatalytic Composite Thin Films

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The uniform transparent TiO2/SiO2 photocatalytic composite thin films are prepared by sol-gel method on the soda lime glass substrates, and characterized by UV-visible spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), BET surface area, FTIR spectroscopy and X-ray photoelectron spectroscopy (XPS). It was found that the addition of SiO2 to TiO2 thin films can suppress the grain growth of TiO2 crystal, increase the hydroxyl content on the surface of TiO2 films, lower the contact angle for water on TiO2 films and enhance the hydrophilic property of TiO2 films. The super-hydrophilic TiO2/SiO2 photocatalytic composite thin films with the contact angle of 0-° are obtained by the addition of 10%-20% SiO2 in mole fraction.

  15. Enhanced electrochromic properties of TiO2 nanoporous film prepared based on an assistance of polyethylene glycol

    Science.gov (United States)

    Xu, Shunjian; Luo, Xiaorui; Xiao, Zonghu; Luo, Yongping; Zhong, Wei; Ou, Hui; Li, Yinshuai

    2017-01-01

    Polyethylene glycol (PEG) was employed as pore-forming agent to prepare TiO2 nanoporous film based on spin-coating a TiO2 nanoparticle mixed paste on fluorine doped tin oxide (FTO) glass. The electrochromic and optical properties of the obtained TiO2 film were investigated by cyclic voltammetry (CV), chronoamperometry (CA) and UV–Vis spectrophotometer. The results show that the PEG in the mixed paste endows the TiO2 film with well-developed porous structure and improves the uniformity of the TiO2 film, which are helpful for the rapid intercalation and extraction of lithium ions within the TiO2 film and the strengthening of the diffuse reflection of visible light in the TiO2 film. As a result, the TiO2 film derived from the mixed paste with PEG displays higher electrochemical activity and more excellent electrochromic performances compared with the TiO2 film derived from the mixed paste without PEG. The switching times of coloration/bleaching are respectively 10.16/5.65 and 12.77/6.13 s for the TiO2 films with PEG and without PEG. The maximum value of the optical contrast of the TiO2 film with PEG is 21.2% while that of the optical contrast of the TiO2 film without PEG is 14.9%. Furthermore, the TiO2 film with PEG has better stability of the colored state than the TiO2 film without PEG.

  16. In-situ TEM Study on Microstructural Evolution of Nanostructured TiO2

    Institute of Scientific and Technical Information of China (English)

    SHAO Yanqun; TANG Dian; XIONG Weihao

    2007-01-01

    The effect of electron beam on the microstructures and phase transformation of nanostructured TiO2 heat treated at various temperatures for different time was studied by in-situ TEM and SAED. Anatase ex-situ heated at 250℃ and 360℃ transformed to rutile while irradiated by the electron beam. With the increasing sizes and distribution of the powders on the amorphous carbon, the process of phase transformation by the electron beam was encumbered. These evolutions may be due to the changes of vacuum atmosphere and the properties of powders.

  17. Fabrication of regular TiO2 nanoporous films derived by combining nanoimprint technique with sol-gel method.

    Science.gov (United States)

    Zhong, Peng; Que, Wenxiu; Zhang, Jin

    2010-11-01

    In this paper, honeycomb-like regular TiO2 nanoporous films deposited on different substrates including ITO glass and silicon wafer are fabricated by combining a nanoimprint technique with a sol-gel method. A novel soft polymer mold containing a thin layer of polymethylmethacrylate and a thicker layer of polydimethylsiloxane, which is obtained from an anodic aluminum oxide template, is carried out for the nanoimprint process. TiO2 precursor solution prepared by the sol-gel processing is used as the nanoimprinted material. After imprinting, the polydimethylsiloxane back layer is easily peeled off before the polymethylmethacrylate mold is chemically removed to avoid any demolding problem. The SEM images show that the honeycomb-like regular nanostructure of the initial anodic aluminum oxide template can be preserved completely on TiO2 via this method, and the XRD results indicate that there is a crystalline transition from amorphous to anatase of TiO2 after 450 degrees C heat treatment.

  18. Application of Turkevich Method for Gold Nanoparticles Synthesis to Fabrication of SiO2@Au and TiO2@Au Core-Shell Nanostructures

    Directory of Open Access Journals (Sweden)

    Paulina Dobrowolska

    2015-05-01

    Full Text Available The Turkevich synthesis method of Au nanoparticles (AuNPs was adopted for direct fabrication of SiO2@Au and TiO2@Au core-shell nanostructures. In this method, chloroauric acid was reduced with trisodium citrate in the presence of amine-functionalized silica or titania submicroparticles. Core-shells obtained in this way were compared to structures fabricated by mixing of Turkevich AuNPs with amine-functionalized silica or titania submicroparticles. It was found that by modification of reaction conditions of the first method, such as temperature and concentration of reagents, control over gold coverage on silicon dioxide particles has been achieved. Described method under certain conditions allows fabrication of semicontinuous gold films on the surface of silicon dioxide particles. To the best of our knowledge, this is the first report describing use of Turkevich method to direct fabrication of TiO2@Au core-shell nanostructures.

  19. Construction of hierarchical nanostructured TiO2/Bi2MoO6 heterojunction for improved visible light photocatalysis.

    Science.gov (United States)

    Zhang, Wei-De; Zhu, Li

    2012-08-01

    In this study, Bi2MoO6 hollow microspheres were modified by depositing TiO2 nanoparticles through a simple hydrothermal method. The prepared TiO2/Bi2MoO6 photocatalysts were characterized by scanning and transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and UV-vis diffuse reflectance spectroscopy. The photocatalytic performance of the heterostructured catalysts was evaluated by degradation of methylene blue (MB) under visible-light irradiation (lambda>420 nm). The photocatalysts based on nanostructured Bi2MoO6 and TiO2 exhibit much higher photocatalytic activity than the single-phase Bi2MoO6 or TiO2 and the mechanical mixture of Bi2MoO6 and TiO2 for degradation of MB under the same conditions. The results reported in this study provide insight into constructing other heterostructured photocatalysts.

  20. Improvement of optical properties of TiO2 thin film treated with electron beam.

    Science.gov (United States)

    Shin, Joong-Hyeok; Lee, Byung Cheol; Woo, Hee-Gweon; Hwang, Kwang Ha; Jun, Jin

    2013-03-01

    Nanocrystalline titanium dioxide (TiO2) thin films on silicon wafer substrates were prepared by sol-gel spin coating process. The prepared thin films were treated with electron beam (1.1 MeV, 300 kGy) at air atmosphere. The effects of electron-beam (EB) irradiation on the structural and optical properties of the TiO2 thin films were investigated. The structures of all the TiO2 thin films by XRD analysis showed an anatase phase, and the phase remained unchanged within the investigating range of EB treatment. The thickness of the titania thin film decreased slightly with EB treatment whereas the porosity increased. The EB treatment of TiO2 thin film can increase the proportion of Ti3+ in Ti2p at the thin film surface. The optical transmittance of the film in the wavelength ranges of above 380 nm increased after the EB treatment while its refractive index decreased with increasing EB dose. Therefore, improvement of the optical properties could be due to the change in both surface chemistry and morphology of the TiO2 thin films affected by EB irradiation.

  1. Polymer Photovoltaic Cell Using TiO2/G-PEDOT Nanocomplex Film as Electrode

    Directory of Open Access Journals (Sweden)

    F. X. Xie

    2008-01-01

    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.

  2. Phycocyanin assemblies onto nanostructured TiO2 for photovoltaic cells

    Directory of Open Access Journals (Sweden)

    Paula Enciso

    2013-01-01

    Full Text Available The use of renewable energies is of increasing importance due to depletion of fossil fuel sources and environmental damages caused by their utilization. The energy available from the sun is clean and widely distributed. Solar cells are devices used to convert solar energy into electricity. Among them, dye sensitized solar cells are an interesting alternative to conventional silicon ones, because of their low cost and simple assembly process. They are made of a semiconductor with colored dyes adsorbed onto the surface that work as antennas to catch energy in the visible range of the spectra. In this work, nanostructured TiO2 was synthesized and the protein phycocyanin was used as dye. TiO2 was characterized by electron microscopy, X ray diffraction and infrared spectroscopy (FTIR. Phycocyanin was extracted from commercial Spirulina spp. capsules. The assembly process of the electrode covered with TiO2 and phycocyanin was controlled by cyclic voltammetry and FTIR. Results were in accordance with the assembling of an electrode sensitized with phycocyanin.

  3. Electrodeposition of photocatalytic TiO2 film on surface of alumina prepared by anodic oxidation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xin-yu; CHEN Tie-qun

    2004-01-01

    A new electrochemical method to prepare photocatalytic TiO2 thin film was developed, by which the TiO2 was electrodeposited on surface of alumina by AC electrolysis in solution consisting of K2 [TiO(C2O4 )2] and C2H2O4. The deposited TiO2 thin film was primarily characterized by X-ray diffraction (XRD), scanning electronic microscopy (SEM) and energy dispersive spectrum (EDS) methods. The photocatalytic properties of this film were also studied by the photocatalytic degradation of methyl orange. The results show that the TiO2 film electrodeposited by this method is mainly in amorphous and with a little crystalline component mixed anatase and rutile. The surface of the alumina prepared by anodic oxidation is porous and the TiO2 electrodeposited on it is scattered and incompact. TiO2 thin film fixed on the surface of alumina shows photocatalytic activity to the degradation of methyl orange.

  4. Multi-Layered TiO2 Films towards Enhancement of Escherichia coli Inactivation

    Directory of Open Access Journals (Sweden)

    Sorachon Yoriya

    2016-09-01

    Full Text Available Crystalline TiO2 has shown its great photocatalytic properties in bacterial inactivation. This work presents a design fabrication of low-cost, layered TiO2 films assembled reactors and a study of their performance for a better understanding to elucidate the photocatalytic effect on inactivation of E. coli in water. The ability to reduce the number of bacteria in water samples for the layered TiO2 composing reactors has been investigated as a function of time, while varying the parameters of light sources, initial concentration of bacteria, and ratios of TiO2 film area and volume of water. Herein, the layered TiO2 films have been fabricated on the glass plates by thermal spray coating prior to screen printing, allowing a good adhesion of the films. Surface topology and crystallographic phase of TiO2 for the screen-printed active layer have been characterized, resulting in the ratio of anatase:rutile being 80:20. Under exposure to sunlight and a given condition employed in this study, the optimized film area:water volume of 1:2.62 has shown a significant ability to reduce the E. coli cells in water samples. The ratio of surface area of photocatalytic active base to volume of water medium is believed to play a predominant role facilitating the cells inactivation. The kinetic rate of inactivation and its behavior are also described in terms of adsorption of reaction species at different contact times.

  5. Preparation of TiO2 Thin Film and Its Antibacterial Activity

    Institute of Scientific and Technical Information of China (English)

    XU Wei-guo; CHEN An-min; ZHANG Qiang

    2004-01-01

    TiO2 nanometer thin films with photocatalytic antibacterial activity were prepared by the sol-gelmethod on fused quartz and soda lime glass precoated with a SiO2 layer. The thin films were characterized by X-ray photoelectron spectroscopy ( XPS ), scanning electron microscopy (SEM), and X- ray diffraction ( XRD ). Theresults show that sodium and calcium diffusion into nascent TiO2 film is effectively retarded by the SiO2 layer pre-coated on the soda lime glass. The antibacterial activity of the films was determined. The crystalline of TiO2 nano-meter thin film has important effects on the antibacterial activity of the film.

  6. Photocatalytic degradation characteristic of amorphous TiO2-W thin films deposited by magnetron sputtering

    Institute of Scientific and Technical Information of China (English)

    HUANG Jia-mu; LI Yue-xia; ZHAO Guo-dong; CAI Xiao-ping

    2006-01-01

    TiO2-W films were deposited on the slides by reactive magnetron sputtering. Properties of the films were analyzed via AFM,XRD,XPS,STS,UV-Vis and ellipse polarization apparatus. The results show that TiO2-W films are amorphous. The AFM map reveals that the surface of the film is tough and porous. The experiments of decomposing methylene blue indicate that the thickness threshold on these films is 141 nm,at which the rate of photodegradation is 90% in 2 h. And when the thickness is over 141 nm,the rate of photodegradation does not increase any more. This result is completely different from that of crystalloid TiO2 thin film.

  7. Bactericidal and Photocatalytic Activity of Fe3+- TiO2 Thin Films Prepared by the Sol-gel Method

    Institute of Scientific and Technical Information of China (English)

    WANG Xun; GONG Wenqi

    2008-01-01

    Pure TiO2 thin films and iron doped TiO2 thin films on glass substrate were prepared by sol-gel method, and characterized by X-ray diffractometer (XRD), thermo-gravimetric analysis (TG-DSC), high resolution transmission electron microscope (HRTEM), scanning electron microscope (SEM) and UV-Vis spectroscopy, respectively. The experimental results show that the pure TiO2 thin films and iron doped TiO2 thinfilms can destroy most of the eseheriehia coli and bacillus subtillis under the irradiation of 365 nm UV-light.However, the iron doped TiO2 thin film is a better photocatalyst than pure TiO2 thin film. The ultrastructural studies provide direct evidences for understanding the bactericidal mechanism of the TiO2 photocatalyst.

  8. Vertically aligned nanostructured TiO2 photoelectrodes for high efficiency perovskite solar cells via a block copolymer template approach.

    Science.gov (United States)

    Seo, Myung-Seok; Jeong, Inyoung; Park, Joon-Suh; Lee, Jinwoo; Han, Il Ki; Lee, Wan In; Son, Hae Jung; Sohn, Byeong-Hyeok; Ko, Min Jae

    2016-06-02

    We fabricated perovskite solar cells with enhanced device efficiency based on vertically oriented TiO2 nanostructures using a nanoporous template of block copolymers (BCPs). The dimension and shape controllability of the nanopores of the BCP template allowed for the construction of one-dimensional (1-D) TiO2 nanorods and two-dimensional (2-D) TiO2 nanowalls. The TiO2 nanorod-based perovskite solar cells showed a more efficient charge separation and a lower charge recombination, leading to better performance compared to TiO2 nanowall-based solar cells. The best solar cells employing 1-D TiO2 nanorods showed an efficiency of 15.5% with VOC = 1.02 V, JSC = 20.0 mA cm(-2) and fill factor = 76.1%. Thus, TiO2 nanostructures fabricated from BCP nanotemplates could be applied to the preparation of electron transport layers for improving the efficiency of perovskite solar cells.

  9. EFFECT OF ZnFe2O4 DOPING ON THE OPTICALPROPERTIES OF TiO2 THIN FILMS

    Institute of Scientific and Technical Information of China (English)

    李广海; 吴玉程; 张立德

    2001-01-01

    Amorphous TiO2 thin films and ZnFe2O4-doped TiO2 composite films were deposited by radio frequency magnetron sputtering. The effect of ZnFe2O4 doping on the optical properties of TiO2 thin films was reported. Our results show that the absorption edge of TiO2 thin films and composite films exhibits a blueshift with decreasing annealing temperature. The absorption edge of composite films has moved to a visible spectrum range, and a very large redshift occurs in comparison with TiO2 thin films. An enhanced photoluminescence was observed in ZnFe2O4-doped anatase TiO2 thin films at room temperature.

  10. Superhydrophilic TiO2 thin film by nanometer scale surface roughness and dangling bonds

    Science.gov (United States)

    Bharti, Bandna; Kumar, Santosh; Kumar, Rajesh

    2016-02-01

    A remarkable enhancement in the hydrophilic nature of titanium dioxide (TiO2) films is obtained by surface modification in DC-glow discharge plasma. Thin transparent TiO2 films were coated on glass substrate by sol-gel dip coating method, and exposed in DC-glow discharge plasma. The plasma exposed TiO2 film exhibited a significant change in its wetting property contact angle, which is a representative of wetting property, has reduced to considerable limits 3.02° and 1.85° from its initial value 54.40° and 48.82° for deionized water and ethylene glycol, respectively. It is elucidated that the hydrophilic property of plasma exposed TiO2 films dependent mainly upon nanometer scale surface roughness. Variation, from 4.6 nm to 19.8 nm, in the film surface roughness with exposure time was observed by atomic force microscopy (AFM). Analysis of variation in the values of contact angle and surface roughness with increasing plasma exposure time reveal that the surface roughness is the main factor which makes the modified TiO2 film superhydrophilic. However, a contribution of change in the surface states, to the hydrophilic property, is also observed for small values of the plasma exposure time. Based upon nanometer scale surface roughness and dangling bonds, a variation in the surface energy of TiO2 film from 49.38 to 88.92 mJ/m2 is also observed. X-ray photoelectron spectroscopy (XPS) results show change in the surface states of titanium and oxygen. The observed antifogging properties are the direct results of the development of the superhydrophilic wetting characteristics to TiO2 films.

  11. Controlled formation of anatase and rutile TiO2 thin films by reactive magnetron sputtering

    NARCIS (Netherlands)

    Rafieian, Damon; Ogieglo, Wojciech; Savenije, Tom; Lammertink, Rob G.H.

    2015-01-01

    We discuss the formation of TiO2 thin films via DC reactive magnetron sputtering. The oxygen concentration during sputtering proved to be a crucial parameter with respect to the final film structure and properties. The initial deposition provided amorphous films that crystallise upon annealing to an

  12. Charge carrier separation in nanostructured TiO2 photoelectrodes for water splitting.

    Science.gov (United States)

    Cowan, Alexander J; Leng, Wenhua; Barnes, Piers R F; Klug, David R; Durrant, James R

    2013-06-14

    There is intense interest in developing new novel nanostructured photoanodes for water splitting. It is therefore important that methods to analyze the effect of nanostructuring on water splitting yields are developed in order to rationalize the relative merits of this approach for different materials. In this study the dependence of charge separation efficiency (η(sep)) on potential during photoelectrochemical water splitting at pH 2 has been quantified in a model electrode system (nanocrystalline, mesoporous TiO2) using two independent methods. These are (i) analysis of incident photon conversion efficiency (IPCE) measurements and (ii) transient absorption (TA) spectroscopy measurements. The techniques provide good agreement with each other and show that a low maximum value of η(sep) (~0.18) is the primary cause of the low IPCE for water oxidation on these nc-TiO2 electrodes.

  13. Preparation and photoelectrochemical performance of TiO2/Ag2Se interface composite film

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Coupling TiO2 with a narrow band gap semiconductor acting as the photosensitizer has attracted much attention in solar energy exploitation. In this work,the porous TiO2 film was first formed on the conducting glass plate (CGP) substrate by the decomposition of polyethylene glycol (PEG) mixing in titanium hydroxide sol at 450℃. Then,the TiO2/Ag2Se interface composite film was fabricated by interface reaction of AgNO3 with NaSeSO3 on the activated surface of porous TiO2 film. The results of SEM and XRD analyses indicated that the porous TiO2 layer was made up of the anatase crystal,and the Ag2Se layer was made up of congregative small particles that have low-temperature α-phase structure. Due to its efficient charge separation for the photo-induced electron-hole pairs,the TiO2/Ag2Se interface composite film as-prepared has good photovoltaic property and high photocurrent response for visible light,which have been confirmed by the photoelectrochemical measurements.

  14. Locally placed nanoscale gold islands film within a TiO2 photoanode for enhanced plasmon light absorption in dye sensitized solar cells

    Science.gov (United States)

    Kim, Taeheon; Kumaresan, Yogeenth; Cho, Sung Jun; Lee, Chang-Lyoul; Lee, Heon; Jung, Gun Young

    2016-12-01

    As metal nanostructures demonstrated extraordinary plasmon resonance, their optical characteristics have widely been investigated in photo-electronic applications. However, there has been no clear demonstration on the location effect of plasmonic metal layer within the photoanode on both optical characteristics and photovoltaic performances. In this research, the gold (Au) nano-islands (NIs) film was embedded at different positions within the TiO2 nanoparticulate photoanode in dye-sensitized solar cells (DSSC) to check the effect of plasmon resonance location on the device performance; at the top, in the middle, at the bottom of the TiO2 photoanode, and also at all the three positions. The Au NIs were fabricated by annealing a Au thin film at 550 °C. The DSSC having the Au NIs-embedded TiO2 photoanode exhibited an increase in short circuit currents (Jsc) and power conversion efficiency (PCE) owing to the plasmon resonance absorption. Thus, the PCE was increased from 5.92% (reference: only TiO2 photoanode) to 6.52% when the Au NIs film was solely positioned at the bottom, in the middle or at the top of TiO2 film. When the Au NIs films were placed at all the three positions, the Jsc was increased by 16% compared to the reference cell, and consequently the PCE was further increased to 7.01%.

  15. 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.

  16. Synthesis of TiO 2 nanostructured reservoir with temozolomide: Structural evolution of the occluded drug

    Science.gov (United States)

    López, T.; Sotelo, J.; Navarrete, J.; Ascencio, J. A.

    2006-10-01

    Sol-gel synthesized nanostructured TiO 2 matrix were produced with different channel sizes, where drug are immersed, producing a reservoir with Temozolomide (TMZ). This drug is particularly important for the treatment of cancer tumors, which are fundamentally a consequence of the uncontrolled reproduction of human cell. In this way the chemotherapy plays an important role in the treatment of both recurrent and newly diagnosed patients. In the handling of brain tumors TMZ has been discovered as a recent and efficient second generation drug employed in the control of advanced brain gliomas, and it is a welcome addition. Its active component binds to the cancerous DNA cells, thus preventing their disordered growth, destroying them. In this work, we report the synthesis of TiO 2 nanostructured reservoir with TMZ, focusing the effort to the understanding of structural effects on the TMZ configuration by using nuclear magnetic resonance, Raman and IR spectroscopy methods. Our results establish that TMZ molecules are quite sensible to chemical processes and it produces the activation of the molecule, which is followed and understood with help of quantum molecular simulation methods. The study of the molecules allows determining the conditions that produce the activation and chemical selectivity of the molecules, which determines the conditions of synthesis. This information gives parameters for the reservoir structural and chemical optimization.

  17. SILAR deposited TiO2 thin film for supercapacitor application

    Science.gov (United States)

    Deshmukh, P. R.; Lokhande, C. D.

    2013-06-01

    The paper presents the synthesis and characterization of Titanium dioxide (TiO2) thin films prepared by the simple and low cost successive ionic layer adsorption and reaction (SILAR) method. The TiO2 thin films are characterized by scanning electron microscopy (SEM), FT-IR, FT-Raman and UV-VIS spectroscopy techniques. The SEM study of TiO2 shows the cracked morphology on the substrate surface. The characteristic peaks of TiO2 are observed in the FT-IR and FT-Raman studies. The optical study shows band gap of 3.3 eV. The cyclic voltammetry study shows the specific capacitance of 16 F.g-1.

  18. Mobility enhanced photoactivity in sol-gel grown epitaxial anatase TiO2 films.

    Science.gov (United States)

    Jung, Hyun Suk; Lee, Jung-Kun; Lee, Jaegab; Kang, Bo Soo; Jia, Quanxi; Nastasi, Michael; Noh, Jun Hong; Cho, Chin-Moo; Yoon, Sung Hoon

    2008-03-18

    Epitaxial anatase thin films were grown on single-crystal LaAlO3 substrates by a sol-gel process. The epitaxial relationship between TiO2 and LaAlO3 was found to be [100]TiO2||[100]LaAlO3 and (001)TiO2||(001)LaAlO3 based on X-ray diffraction and a high-resolution transmission electron microscopy. The epitaxial anatase films show significantly improved photocatalytic properties, compared with polycrystalline anatase film on fused silica substrate. The increase in the photocatalytic activity of epitaxial anatase films is explained by enhanced charge carrier mobility, which is traced to the decreased grain boundary density in the epitaxial anatase film.

  19. Immobilizing collagen type to TiO2film for improvement of biocompatibility

    Institute of Scientific and Technical Information of China (English)

    Xiao-song JIANG; Jun-ying CHEN; Nan HUANG

    2008-01-01

    In this work, using a bio-chemical modification method, collagen type Ⅰ was immobilized on the TiO2 film surface by a silane coupling reagent of aminopropyl-triethoxysilane. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy were used to investigate the characteristics of the modified TiO2 film. The thrombus formation ability of the films was studied by in vitro platelet adhesion test. Furthermore, the bio-logical behavior of cultured human umbilical vein endothelial cells (HUVECs) onto different films was investigated by in vitro HUVECs cultured experiment. The results show that the modification can improve the biocompatibility of TiO2 film for applications of biome-dical microcoil hemangioma treatment, etc.

  20. Effect of incident deposition angle on optical properties and surface roughness of TiO2 thin films

    Science.gov (United States)

    Pan, Yongqiang; Yang, Chen

    2016-10-01

    Optical properties, surface roughness and packing density of TiO2 thin films are studied by obliquely deposited on K9 glass by electron beam evaporation. The surface roughness of TiO2 thin films with different incident deposition angle is compared. The experimental results show that the transmittance increases and transmittance peak shifts to short wavelength with increasing incident deposition angle, the packing density of TiO2 thin films decrease from 0.80 to 0.34 with incident deposition angle increasing from 0° to 75°. The surface roughness of TiO2 thin films increase with increasing incident deposition angle. The surface roughness of TiO2 thin films is slightly bigger than the surface roughness of K9 substrate when the incident deposition angle is 75°. When the incident deposition angle is constant, TiO2 thin films surface roughness decrease with increase of film thickness.

  1. Intrinsic kinetics of photocatalytic oxidation of formic and oxalic acid on immobilised TiO2 films

    NARCIS (Netherlands)

    McMurray, TA; Byrne, JA; Dunlop, PSM; Winkelman, JGM; Eggins, BR; McAdams, ET

    2004-01-01

    Titanium dioxide (TiO2) photocatalysis is a possible alternative/complementary technology to conventional water treatment methods. The TiO2 catalyst may be used as slurry or it may be immobilised onto a supporting substrate. With immobilised TiO2 films mass transfer problems occur in most

  2. Intrinsic kinetics of photocatalytic oxidation of formic and oxalic acid on immobilised TiO2 films

    NARCIS (Netherlands)

    McMurray, TA; Byrne, JA; Dunlop, PSM; Winkelman, JGM; Eggins, BR; McAdams, ET

    2004-01-01

    Titanium dioxide (TiO2) photocatalysis is a possible alternative/complementary technology to conventional water treatment methods. The TiO2 catalyst may be used as slurry or it may be immobilised onto a supporting substrate. With immobilised TiO2 films mass transfer problems occur in most photocatal

  3. Photoelectrocatalytic Degradation of Humic Acids Using Codoped TiO2 Film Electrodes under Visible Light

    Directory of Open Access Journals (Sweden)

    Xiao Zhou

    2014-01-01

    Full Text Available Cu/N codoped TiO2 films on Ti substrates were successfully prepared by electrochemical method with the goal of enhancing the photoelectrocatalytic activity under visible light. The morphology and composition of the Cu/N codoped films were characterized using field emission scanning electron microscopy (FESEM, X-ray diffraction (XRD, energy dispersive X-ray (EDX, and UV-Vis diffusion reflection spectroscopy (UV-Vis DRS. The photocatalytic activities of the Cu/N codoped TiO2 films were evaluated by the degradation of humic acid. The visible light photocatalytic degradation of humic acid (HA was tested and Cu/N codoped TiO2 films showed the highest degradation efficiency up to 41.5% after 210 minutes of treatment. It showed that Cu2+ and NH4+ codoped TiO2 film significantly improved the photocatalytic efficiency under the visible light. When +5.0 V anodic bias potential and visible light were simultaneously applied, the degradation efficiency of HA over the Cu/N codoped TiO2 films significantly improved to 93.5% after 210 minutes of treatment.

  4. Microstructural, optical and photocatalytic properties of CdS doped TiO2 thin films

    Science.gov (United States)

    Mohamed, S. H.; Shaaban, E. R.

    2011-11-01

    CdS doped TiO2 thin films (with CdS content=0, 3, 6, 9 and 12 at%) were grown on glass substrates. The X-ray diffraction analysis revealed that the films are polycrystalline of monoclinic TiO2 structure. The microstructure parameters of the films such as crystallite size (Dν) and microstrain (e) are calculated. Both the crystallites size and the microstrain are decreased with increasing CdS content. The optical constants have been determined in terms of Murmann's exact equations. The refractive index and extinction coefficient are increased with increasing CdS content. The optical band gap is calculated in the strong absorption region. The possible optical transition in these films is found to be an allowed direct transition. The values of Egopt are found to decrease as the CdS content increased. The films with 3 at% CdS content have better decomposition efficiency than undoped TiO2. The films with 6 at% and 9 at% CdS content have decomposition efficiency comparable to that of undoped TiO2, although they have lower band gap. The CdS doped TiO2 could have a better impact on the decomposing of organic wastes.

  5. Comparison of photocatalytic activity of TiO2 film doped nonuniformly by Mn and Zn

    Institute of Scientific and Technical Information of China (English)

    XU Wei; LI Xin-jun; ZHENG Shao-jian; WANG Jun-gang; XU Zhong-kui

    2005-01-01

    The thin films of TiO2, doped by Mn or Zn with nonuniform distribution, were prepared by sol-gel method under process control. The actinic absorption of the catalyst thin films was evaluated by UV-vis spectrophotometry. And the activity of the photocatalyst was evaluated by photocatalytic degradation kinetics of aqueous methyl orange under UV radiation. The results show that the photocatalytic activity of the TiO2 thin film can be evidently enhanced by Mn non-uniformly doping in the bottom layer and can be decreased by Mn doping in the surface layer.The activity of TiO2 thin film can be evidently enhanced by Zn non-uniform doping in either the bottom or the surface layer. But the activity of TiO2 is less affected by uniformly Zn doping. The different mechanisms for enhanced photocatalytic activity of Mn or Zn non-uniformly doped titanium dioxide film were discussed in terms of the separation of photon-generated carrier in the TiO2 films.

  6. 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.

  7. Calcination/acid-activation treatment of an anodic oxidation TiO2/Ti film catalyst

    Institute of Scientific and Technical Information of China (English)

    YAO Zhongping; JIANG Yanli; JIANG Zhaohua; ZHU Hongkui; BAI Xuefeng

    2009-01-01

    The aim of this work was to investigate the effects of calcination/acid-activation on the composition, structure, and photocatalytic (PC) re-duction property of an anodic oxidation TiO2/Ti film catalyst. The surface morphology and phase composition were examined by scanning electron microscopy and X-ray diffraction. The catalytic property of the film catalysts was evaluated through the removal rate of potassium chromate during the PC reduction process. The results showed that the film catalysts were composed of anatase and mtile TiO2 with a mi-cro-porous surface structure. The calcination treatment increased the content of TiO2 in the film, changed the relative ratio of anatase and rutile TiO2, and decreased the size of the micro pores of the film cat.a/ysts. The removal rate of potassium chromate was related to the tech-nique parameters of calcination/acid-activation treatment. When the anodic oxidation TiO2Ti film catalyst was calcined at 873 K for 30 min and then acid-activated in the concentrated H2SO4 for 60 min, it presented the highest catalytic property, with the removal rate of potassium chromate of 96.3% during the PC reduction process under the experimental conditions.

  8. 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

  9. α-Fe2O3/TiO2 3D hierarchical nanostructures for enhanced photoelectrochemical water splitting.

    Science.gov (United States)

    Han, Hyungkyu; Riboni, Francesca; Karlicky, Frantisek; Kment, Stepan; Goswami, Anandarup; Sudhagar, Pitchaimuthu; Yoo, Jeongeun; Wang, Lei; Tomanec, Ondrej; Petr, Martin; Haderka, Ondrej; Terashima, Chiaki; Fujishima, Akira; Schmuki, Patrik; Zboril, Radek

    2017-01-07

    We report the fabrication of 3D hierarchical hetero-nanostructures composed of thin α-Fe2O3 nanoflakes branched on TiO2 nanotubes. The novel α-Fe2O3/TiO2 hierarchical nanostructures, synthesized on FTO through a multi-step hydrothermal process, exhibit enhanced performances in photo-electrochemical water splitting and in the photocatalytic degradation of an organic dye, with respect to pure TiO2 nanotubes. An enhanced separation of photogenerated charge carriers is here proposed as the main factor for the observed photo-activities: electrons photogenerated in TiO2 are efficiently collected at FTO, while holes are transferred to the α-Fe2O3 nanobranches that serve as charge mediators to the electrolyte. The morphology of α-Fe2O3 that varies from ultrathin nanoflakes to nanorod/nanofiber structures depending on the Fe precursor concentration was shown to have a significant impact on the photo-induced activity of the α-Fe2O3/TiO2 composites. In particular, it is shown that for an optimized photo-electrochemical structure, a combination of critical factors should be achieved such as (i) TiO2 light absorption and photo-activation vs.α-Fe2O3-induced shadowing effect and (ii) the availability of free TiO2 surface vs.α-Fe2O3-coated surface. Finally, theoretical analysis, based on DFT calculations, confirmed the optical properties experimentally determined for the α-Fe2O3/TiO2 hierarchical nanostructures. We anticipate that this new multi-step hydrothermal process can be a blueprint for the design and development of other hierarchical heterogeneous metal oxide electrodes suitable for photo-electrochemical applications.

  10. Graphene oxide nanosheets as an effective template for the synthesis of porous TiO2 film in dye-sensitized solar cells

    Science.gov (United States)

    Wang, Ping; He, Fenglong; Wang, Jin; Yu, Huogen; Zhao, Li

    2015-12-01

    Template method by using various organic components as the pore-forming agent is an effective strategy for the preparation of various porous inorganic materials. After high-temperature calcination in air, the organic components can be in situ decomposed into the gaseous CO2, resulting in the formation of porous structures in inorganic materials. In addition to the well-known organic components, it is highly required to develop new and simple carbon-containing template to prepare porous inorganic nanostructures. In this study, graphene oxide (GO) nanosheets were used as a new template for the preparation of porous TiO2 film photoelectrode, which can be applied in dye-sensitized solar cells (DSSCs). The porous TiO2 film was fabricated via a three-step method, including the initially homogeneous grafting of GO nanosheets on the TiO2 surface (TiO2-GO), the preparation of TiO2-GO film using blade method and final formation of porous structure after the in situ removal of GO by high-temperature calcination. The effect of GO content on photoelectric conversion performance of the as-fabricated DSSCs was investigated. It was found that the conversion efficiency of DSSC based on porous TiO2-GO (0.75%) film reached up to a maximum value (4.65%), which was much higher than that of DSSC based on nonporous TiO2 film (4.01%). The enhanced conversion efficiency can be attributed to the formation of more porous structures caused by the GO nanosheets after high-temperature calcination. This work may provide a new insight for preparing other porous structured materials.

  11. TiO2 thin films prepared by sol - gel method

    Science.gov (United States)

    Suciu, R. C.; Indrea, E.; Silipas, T. D.; Dreve, S.; Rosu, M. C.; Popescu, V.; Popescu, G.; Nascu, H. I.

    2009-08-01

    There is a growing awareness that titania (TiO2) and TiO2-based oxide systems are the most promising candidates for the development of photoelectrodes for photoelectrochemical cell (PEC) for solar-hydrogen production [1]. The PEC is equipped with a single photoelectrode (photoanode) and cathode, both of which are immersed in an aqueous electrolyte. In this work we present a sol-gel method to prepare TiO2 thin films on ITO using tetraisopropoxides of titanium, acetylacetone, 1-butanol and Tween 80 as surfactant. The films were deposited on ITO coated glass slides by spray pyrolysis. UV-VIS spectra and fluorescence measurements were made for the solutions and films. X-ray diffraction was used for structural investigations and the morphology of the film was studied by Scanning Electron Microscopy.

  12. Fabrication of UV Photodetector on TiO2/Diamond Film.

    Science.gov (United States)

    Liu, Zhangcheng; Li, Fengnan; Li, Shuoye; Hu, Chao; Wang, Wei; Wang, Fei; Lin, Fang; Wang, Hongxing

    2015-09-24

    The properties of ultraviolet (UV) photodetector fabricated on TiO2/diamond film were investigated. Single crystal diamond layer was grown on high-pressure-high-temperature Ib-type diamond substrate by microwave plasma chemical vapor deposition method, upon which TiO2 film was prepared directly using radio frequency magnetron sputtering technique in Ar and O2 mixing atmosphere. Tungsten was used as electrode material to fabricate metal-semiconductor-metal UV photodetector. The dark current is measured to be 1.12 pA at 30 V. The photo response of the device displays an obvious selectivity between UV and visible light, and the UV-to-visible rejection ratio can reach 2 orders of magnitude. Compared with that directly on diamond film, photodetector on TiO2/diamond film shows higher responsivity.

  13. 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.

  14. TiO2 and Fe2O3 films for photoelectrochemical water splitting.

    Science.gov (United States)

    Krysa, Josef; Zlamal, Martin; Kment, Stepan; Brunclikova, Michaela; Hubicka, Zdenek

    2015-01-09

    Titanium oxide (TiO2) and iron oxide (α-Fe2O3) hematite films have potential applications as photoanodes in electrochemical water splitting. In the present work TiO2 and α-Fe2O3 thin films were prepared by two methods, e.g., sol-gel and High Power Impulse Magnetron Sputtering (HiPIMS) and judged on the basis of physical properties such as crystalline structure and surface topography and functional properties such as simulated photoelectrochemical (PEC) water splitting conditions. It was revealed that the HiPIMS method already provides crystalline structures of anatase TiO2 and hematite Fe2O3 during the deposition, whereas to finalize the sol-gel route the as-deposited films must always be annealed to obtain the crystalline phase. Regarding the PEC activity, both TiO2 films show similar photocurrent density, but only when illuminated by UV light. A different situation was observed for hematite films where plasmatic films showed a tenfold enhancement of the stable photocurrent density over the sol-gel hematite films for both UV and visible irradiation. The superior properties of plasmatic film could be explained by ability to address some of the hematite drawbacks by deposition of very thin films (25 nm) consisting of small densely packed particles and by doping with Sn.

  15. TiO2 and Fe2O3 Films for Photoelectrochemical Water Splitting

    Directory of Open Access Journals (Sweden)

    Josef Krysa

    2015-01-01

    Full Text Available Titanium oxide (TiO2 and iron oxide (α-Fe2O3 hematite films have potential applications as photoanodes in electrochemical water splitting. In the present work TiO2 and α-Fe2O3 thin films were prepared by two methods, e.g., sol-gel and High Power Impulse Magnetron Sputtering (HiPIMS and judged on the basis of physical properties such as crystalline structure and surface topography and functional properties such as simulated photoelectrochemical (PEC water splitting conditions. It was revealed that the HiPIMS method already provides crystalline structures of anatase TiO2 and hematite Fe2O3 during the deposition, whereas to finalize the sol-gel route the as-deposited films must always be annealed to obtain the crystalline phase. Regarding the PEC activity, both TiO2 films show similar photocurrent density, but only when illuminated by UV light. A different situation was observed for hematite films where plasmatic films showed a tenfold enhancement of the stable photocurrent density over the sol-gel hematite films for both UV and visible irradiation. The superior properties of plasmatic films could be explained by ability to address some of the hematite drawbacks by the deposition of very thin films (25 nm consisting of small densely packed particles and by doping with Sn.

  16. TiO2 Sub-microsphere Film as Scaffold Layer for Efficient Perovskite Solar Cells.

    Science.gov (United States)

    Huang, Yang; Zhu, Jun; Ding, Yong; Chen, Shuanghong; Zhang, Changneng; Dai, Songyuan

    2016-03-01

    TiO2 sub-microspheres composed of anatase granular-like nanocrystallines with an average diameter ∼250 nm are synthesized using sol-gel method and employed as the scaffold layer for efficient mesocopic perovskite solar cells. Compared with mesoporous TiO2 films composed of ∼18 nm nanoparticles, the sub-microsphere films show superior light-trapping characteristics and significantly improve the light-harvesting capability of the solar cells. In addition, the charge-transport performance is also dramatically improved according to the transient photocurrent decay despite there being no significant difference in the perovskite layer surface morphology. As a result, an average power conversion efficiency of 15% with a highly uniform distribution is achieved for the solar cells with TiO2 sub-microsphere films, 12% higher than those with TiO2 nanoparticle films. The combination of light-harvesting capability and fast charge transfer make the TiO2 sub-microsphere film a good candidate as the scaffold layer for efficient perovskite solar cells.

  17. Preparation and Characterization of Nano-ZnFe2O4/TiO2 Films

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The nano-ZnFe2O4/TiO2 films possess the functions of desulfurization and degradation for organic pollutants. The sols of ZnFe2O4/TiO2 were prepared by sol-gel method and coated on glass and porous ceramic by vertical coating and dipping-lift processes, respectively, and the samples were obtained after drying and sintering. The composition, appearance, absorption spectrum of the films,and the influence of the film on porous ceramic performances were analyzed using SEM, AFM, UVVis spectrometer, and mercury porosimeter, respectively, to determine the operation parameters of the multifunction porous ceramic elements for gas-purification.

  18. Photoelectric Characteristics of Nano TiO2 Film Prepared By Spraying Pyrolysis Method

    OpenAIRE

    Cuong Tran Kim

    2015-01-01

    The nanocrystalline TiO2 (nc TiO2) film was prepared by spraying pyrolysis method. Starting material for the synthesis was TiCl4. Phase compositions and crystalline sizes were examined by pattern of XRD, and surface morphology of the thin film was analyzed by SEM and AFM. Optical characteristics were examined by UV – Vis and luminescent spectra (PL). Electric characteristics were examined by measuring resistance changing of films versus temperature. The experimental data ...

  19. Attempts to improve the H2S sensitivity of TiO2 films

    Science.gov (United States)

    Jagadale, T. C.; Nagmani, Ramgir, N. S.; Prajapat, C. L.; Debnath, A. K.; Aswal, D. K.; Gupta, S. K.

    2016-05-01

    We report the pulsed laser deposited titanium oxide thin film for H2S gas sensing. The surface and bulk electronic structure is revealed using XPS technique. These TiO2 films showed very good selectivity to H2S with response of around ~ 60% at 200°C operating temperature. In order to improve the sensor response so as to realize the technological application, we hereby attempted bi-directional efforts as (i) Nb-doping and (ii) defects engineering in the TiO2 film. It is revealed that Nb-doping reduces response however defect engineering improves the same.

  20. Properties of TiO2 thin films and a study of the TiO2-GaAs interface

    Science.gov (United States)

    Chen, C. Y.; Littlejohn, M. A.

    1977-01-01

    Titanium dioxide (TiO2) films prepared by chemical vapor deposition were investigated in this study for the purpose of the application in the GaAs metal-insulator-semiconductor field-effect transistor. The degree of crystallization increases with the deposition temperature. The current-voltage study, utilizing an Al-TiO2-Al MIM structure, reveals that the d-c conduction through the TiO2 film is dominated by the bulk-limited Poole-Frenkel emission mechanism. The dependence of the resistivity of the TiO2 films on the deposition environment is also shown. The results of the capacitance-voltage study indicate that an inversion layer in an n-type substrate can be achieved in the MIS capacitor if the TiO2 films are deposited at a temperature higher than 275 C. A process of low temperature deposition followed by the pattern definition and a higher temperature annealing is suggested for device fabrications. A model, based on the assumption that the surface state densities are continuously distributed in energy within the forbidden band gap, is proposed to interpret the lack of an inversion layer in the Al-TiO2-GaAs MIS structure with the TiO2 films deposited at 200 C.

  1. Quantum-Dot-Sensitized Solar Cells: Effect of Nanostructured TiO2 Morphologies on Photovoltaic Properties.

    Science.gov (United States)

    Toyoda, Taro; Shen, Qing

    2012-07-19

    There is a great deal of interest in dye-sensitized solar cells (DSCs) fabricated with nanostructured TiO2 electrodes. Many different dye molecules have been designed and synthesized to achieve high photovoltaic conversion efficiency. Recently, as an alternative to organic dyes, semiconductor quantum dots (QDs) have been studied for their light-harvesting capability compared with other sensitizers. Accordingly, an attractive configuration to exploit these fascinating properties of semiconductor QDs is the quantum-dot-sensitized solar cell (QDSC) due to their high photoactivity, process realization, and low cost of production. The morphology of TiO2 electrodes included with surface orientation is important for satisfactory assembly of QDSCs in order to improve the efficiency. Breakthroughs allowing an increase in efficiency will advance on two areas of electrode morphology control, namely, (A) TiO2 nanotube electrodes and (B) inverse opal TiO2 electrodes.

  2. The influence of metal interlayers on the structural and optical properties of nano-crystalline TiO 2 films

    KAUST Repository

    Yang, Yong

    2012-03-01

    TiO 2-M-TiO 2 (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 TiO 2-W-TiO 2 and TiO 2-Co-TiO 2 films showed crystalline phases, whereas the TiO 2-Ag-TiO 2 films remained in the amorphous state. The crystallization temperature for the TiO 2-M-TiO 2 films decreased significantly compared with pure TiO 2 film deposited on quartz. Detailed analysis of the Raman spectra suggested that the crystallization of TiO 2-M-TiO 2 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 TiO 2 matrix. These results indicate that the insertion of intermediate metal layers provides a feasible access to improve the structural and optical properties of anatase TiO 2 films, leading to promising applications in the field of photocatalysis. © 2011 Elsevier B.V. All rights reserved.

  3. The Photocatalytic Activity and Compact Layer Characteristics of TiO2 Films Prepared Using Radio Frequency Magnetron Sputtering

    Directory of Open Access Journals (Sweden)

    H. C. Chang

    2014-01-01

    Full Text Available TiO2 compact layers are used in dye-sensitized solar cells (DSSCs to prevent charge recombination between the electrolyte and the transparent conductive substrate (indium tin oxide, ITO; fluorine-doped tin oxide, FTO. Thin TiO2 compact layers are deposited onto ITO/glass by means of radio frequency (rf magnetron sputtering, using deposition parameters that ensure greater photocatalytic activity and increased DSSC conversion efficiency. The photoinduced decomposition of methylene blue (MB and the photoinduced hydrophilicity of the TiO2 thin films are also investigated. The photocatalytic performance characteristics for the deposition of TiO2 films are improved by using the Grey-Taguchi method. The average transmittance in the visible region exceeds 85% for all samples. The XRD patterns of the TiO2 films, for sol-gel with spin coating of porous TiO2/TiO2 compact/ITO/glass, show a good crystalline structure. In contrast, without the TiO2 compact layer (only porous TiO2, the peak intensity of the anatase (101 plane in the XRD patterns for the TiO2 film has a lower value, which demonstrates inferior crystalline quality. With a TiO2 compact layer to prevent charge recombination, a higher short-circuit current density is obtained. The DSSC with the FTO/glass and Pt counter electrode demonstrates the energy conversion efficiency increased.

  4. Correlation of Photocatalysis and Photoluminescence Effect in Relation to the Surface Properties of TiO2:Tb Thin Films

    Directory of Open Access Journals (Sweden)

    Damian Wojcieszak

    2013-01-01

    Full Text Available In this paper structural, optical, photoluminescence, and photocatalytic properties of TiO2 and TiO2:(2.6 at. % Tb thin films have been compared. Thin films were prepared by high-energy reactive magnetron sputtering process, which enables obtaining highly nanocrystalline rutile structure of deposited films. Crystallites sizes were 8.7 nm and 6.6 nm for TiO2 and TiO2:Tb, respectively. Surface of prepared thin films was homogenous with small roughness of ca. 7.2 and 2.1 nm in case of TiO2 and TiO2:Tb samples, respectively. Optical properties measurements have shown that the incorporation of Tb into TiO2 matrix has not changed significantly the thin films transparency. It also enables obtaining photoluminescence effect in wide range from 350 to 800 nm, what is unique phenomenon in case of TiO2 with rutile structure. Moreover, it has been found that the incorporation of 2.6 at. % of Tb has increased the photocatalytic activity more than two times as compared to undoped TiO2. Additionally, for the first time in the current state of the art, the relationship between photoluminescence effect, photocatalytic activity, and surface properties of TiO2:Tb thin films has been theoretically explained.

  5. Zirconium doped TiO2 thin films deposited by chemical spray pyrolysis

    Science.gov (United States)

    Juma, A.; Oja Acik, I.; Oluwabi, A. T.; Mere, A.; Mikli, V.; Danilson, M.; Krunks, M.

    2016-11-01

    Chemical spray pyrolysis (CSP) is a flexible deposition technique that allows for mixing of the precursor solutions in different proportions suitable for doping thin films. The CSP method was used to dope TiO2 thin films with Zr by adding zirconium(IV) acetylacetonate into a solution of titanium(IV) isopropoxide in ethanol stabilized by acetylacetone at [Zr]/[Ti] of 0, 5, 10 and 20 at%. The Zr-doped TiO2 thin films were uniform and homogeneous showing much smaller grains than the undoped TiO2 films. Zr stabilized the anatase phase to temperatures above 800 °C depending on Zr concentration in the spray solution. The concentration of Zr determined by XPS was 6.4 at% for the thin film deposited from the 20 at% solution. According to AFM studies, Zr doping decreased the root mean square roughness of TiO2 film from 5.9 to 1.1 nm. An XRD study of samples with the highest Zr amount showed the ZrTiO4 phase started forming after annealing at 800 °C. The optical band gap for TiO2 decreased from 3.3 eV to 3.0 eV after annealing at 800 °C but for the TiO2:Zr(20) film it remained at 3.4 eV. The dielectric constant increased by more than four times with Zr-doping and this was associated with the change in the bond formations caused by substitution of Ti by Zr in the lattice.

  6. Self-cleaning glass coated with Fe3+-TiO2 thin film

    Institute of Scientific and Technical Information of China (English)

    卢安贤; 林娜; 李雪; 谭常优

    2004-01-01

    The self-cleaning glass coated with Fe3+-TiO2 photocatalytic thin film was prepared by sol-gel process from the system Ti(OC4H9)4-NH(C2H4OH)2-C2H5OH-H2O containing FeCl3. The microstructure and properties of the film were studied using differential thermal analysis-thermogravimetry(DTA-TG), X-ray diffration(XRD) and scanning electron microscope(SEM). The transmittance of the self-cleaning glass was measured by using UV-Vis spectrometer. The effects of content of Fe3+ and the thickness of Fe3+-TiO2 thin film on the photocatalytic activity were examined. The results show that the photocatalytic thin films are mainly composed of Fe3O4 and TiO2 particles within 10-100 nm. The appropriate amount of Fe3+ is effective for improving the photocatalytic activities of TiO2. The best photocatalytic activity is obtained when the molar ratio of Fe3+ to TiO2 is 0.005 and the glass is coated with 9 layers.

  7. Inkjet printed highly porous TiO2 films for improved electrical properties of photoanode.

    Science.gov (United States)

    Bernacka-Wojcik, I; Wojcik, P J; Aguas, H; Fortunato, E; Martins, R

    2016-03-01

    The aim of presented work is to show the improvements obtained in the properties of TiO2 films for dye sensitized solar cells fabricated by inkjet printing using an innovative methodology. We describe the development and properties of TiO2-based inks used in a lab-scale printer, testing various commercial TiO2 pastes. The porosity of the deposited inkjet printed TiO2 films is much higher than using the conventional "doctor blade" deposition technique, as the ink solvent evaporates during the droplet fly from the nozzle to the substrate due to its picoliter volume and the applied heating of a printing stage (70°C). Thanks to higher surface area, the dye sensitized solar cells incorporating inkjet printed TiO2 film gave higher efficiencies (ηmax≈3.06%) than the more compact films obtained by the "doctor blade" method (ηmax≈2.56%). Furthermore, electrochemical analysis indicates that for whole tested thickness range, the inkjet printed layers have higher effective electron diffusion length indicating their better transport properties.

  8. Nanostructured anatase TiO2 densified at high pressure as advanced visible light photocatalysts.

    Science.gov (United States)

    Carini, Giovanni; Parrino, Francesco; Palmisano, Giovanni; Scandura, Gabriele; Citro, Ilaria; Calogero, Giuseppe; Bartolotta, Antonino; Di Marco, Gaetano

    2015-09-26

    This study reports on characterization and photoactivity of nanostructured TiO2 samples, which have been permanently densified under high pressures, up to 2.1 GPa. Commercial Mirkat 211 anatase has been used as a benchmark sample, in order to investigate the effect of unidirectional high pressure on structural, optical and photocatalytic properties of TiO2. Vibrational Raman spectroscopy shows that the treatment does not cause transitions among the different crystalline phases of titanium dioxide. UV-vis diffuse reflectance spectra reveal that increasing pressure gives rise to a shift of the absorption onset towards higher wavelength enhancing the photoactivity under visible radiation. Samples are also photo-electrochemically characterized and tested in the gas phase with partial oxidation of ethanol to acetaldehyde under visible irradiation. Compaction up to 0.8 GPa depresses both the alcohol conversion and the aldehyde yield, while samples treated under higher pressures show enhanced characteristics of conversion compared to the pristine material. Moreover, promising results in the reduction of CO2 are also obtained under UV-visible radiation.

  9. Photocatalytic performance of TiO2 thin films connected with Cu micro-grid

    Institute of Scientific and Technical Information of China (English)

    ZHU HaiLing; ZHANG JunYing; WANG TianMin; WANG LiuGang; LAN Xiang; HUANG BaiBiao

    2009-01-01

    Aiming at reducing the recombination of photo-induced carriers in semiconductor photocatalyticprocess,we prepared TiO2 thin film with its surface modified by a connected Cu micro-grid via a microsphere lithography strategy,which showed higher photocatalytic activity than the pure TiO2 film.The improvement of photocataiytic activity of Cu micro-grid to the TiO2 film is due to the charge carrier separation and electron transfer by the conducting metal grid.The photocatalyUc activity was improved as metal loading increased,which obtained the best performance at a certain loading amount,and then decreased at higher loading amount.This phenomenon was attributed to the metal's bulk effect which could be explained by the relationship between the energetic positions and the metal cluster size.

  10. Photocatalytic performance of TiO2 thin films connected with Cu micro-grid

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Aiming at reducing the recombination of photo-induced carriers in semiconductor photocatalytic process, we prepared TiO2 thin film with its surface modified by a connected Cu micro-grid via a microsphere lithography strategy, which showed higher photocatalytic activity than the pure TiO2 film. The improvement of photocatalytic activity of Cu micro-grid to the TiO2 film is due to the charge carrier separation and electron transfer by the conducting metal grid. The photocatalytic activity was improved as metal loading increased, which obtained the best performance at a certain loading amount, and then decreased at higher loading amount. This phenomenon was attributed to the metal’s bulk effect which could be explained by the relationship between the energetic positions and the metal cluster size.

  11. Synthesis of TiO2-doped SiO2 composite films and its applications

    Indian Academy of Sciences (India)

    Xiaojun Zhang; Huagui Zheng

    2008-10-01

    The TiO2-doped SiO2 composite films were prepared by two-step sol–gel method and then it was applied in the degradation of methylene red (MR) as photocatalysts. In XRD, FT–IR, and TEM investigations of these TiO2-doped SiO2 composite films, the titanium oxide species are highly dispersed in the SiO2 matrixes and exist in a tetrahedral form. And special attention has been focused on the relationship between the local structure of the titanium oxide species in the TiO2-doped SiO2 composite films and the photocatalytic reactivity in order to provide vital information for the design and application of such highly efficient photocatalytic systems in the degradation of toxic compounds diluted in a liquid phase.

  12. Raman spectral analysis of TiO2 thin films doped with rare-earth samarium.

    Science.gov (United States)

    Yang, Chang-Hu; Ma, Zhong-Quan

    2012-08-01

    TiO(2) thin films doped with rare-earth samarium were prepared on a quartz plate by the sol-gel/spin-coating technique. The samples were annealed at 700 °C to 1100 °C, and the Raman spectra of the samples were obtained. Analyses of Raman spectra show that samarium doping can inhibit the anatase-rutile phase transition. Samarium doping can refine grains of TiO(2) thin films and increase the internal stress, thereby preventing lattice vibration. Nanocrystalline TiO(2) thin films obviously show the phonon confinement effect, i.e., the blueshift of characteristic Raman peak and full width at half-height increase, and the peak shapes asymmetrically broaden with a decrease in the grain sizes of the samples.

  13. Comparison of photovoltaic performance of TiO2 nanoparticles based thin films via different routes

    Science.gov (United States)

    Ji, Yajun

    2015-11-01

    Well crystallized TiO2 nanoparticles were prepared by hydrothermal and sol-gel routes, respectively. The morphologies, structures, crystallinity and optical properties of resulted TiO2 nanoparticles-based thin films via the two methods were examined by field emission scanning electron microscope (FE-SEM), transmission electron microscope (TEM), X-ray diffractometer (XRD) and reflectance spectra. In addition, comparison of photovoltaic performance of TiO2 nanoparticles-based thin films by the two methods was performed. It is found that the maximum energy conversion efficiency of 4.06% was achieved based on the obtained electrode via hydrothermal, which is much better than that of the sol-gels route. The uniform film structure with improved dye absorption capability, increased diffused reflectance property and relatively low charge recombination rates for injected electrons are believed to be responsible to the superior photoelectrochemical properties of dye-sensitized solar cells (DSSC) via hydrothermal route.

  14. A novel sol-gel method for preparing favorable TiO2 thin film

    Science.gov (United States)

    Wang, Xiaoyi; Zhang, Dainan; Li, Jie; Zhong, Zhiyong; Jia, Lijun; Wen, Tianlong; Zhang, Huaiwu; Liao, Yulong

    2016-01-01

    Nanocrystalline TiO2 thin films were synthesized by the sol-gel spin-coating method with different variables. Tetrabutyl titanate (TBOT) proportion and C5H8O2: TBOT molar ratio were confirmed to be influential on the gelation time. X-ray diffraction analysis indicated that the samples presented rutile TiO2 phases, which is a basis for subsequent experiments. Scanning electron microscope results revealed that TiO2 thin films with homogeneous and compact surfaces were synthesized successfully when adding moderate TBOT. It was found the thickness of films could reach about 60 nm when sintered at 750 °C, and the influence of sintering temperature was also investigated.

  15. Zirconium doped TiO2 thin films: A promising dielectric layer

    Science.gov (United States)

    Kumar, Arvind; Mondal, Sandip; Rao, K. S. R. Koteswara

    2016-05-01

    In the present work, we have fabricated the zirconium doped TiO2 thin (ZTO) films from a facile spin - coating method. The addition of Zirconium in TiO2 offers conduction band offset to Si and consequently decreased the leakage current density by approximately two orders as compared to pure TiO2 thin (TO) films. The ZTO thin film shows a high dielectric constant 27 with a very low leakage current density ˜10-8 A/cm2. The oxide capacitate, flat band voltage and change in flat band voltage are 172 pF, -1.19 V and 54 mV. The AFM analysis confirmed the compact and pore free flat surface. The RMS surface roughness is found to be 1.5 Å. The ellipsometry analysis also verified the fact with a high refractive index 2.21.

  16. Photoelectrochemical Water Splitting of Nitrogen and Hydrogen Treated P25 TiO2 Films

    Science.gov (United States)

    Zavodivker, Liat S.

    Photoelectrochemical data is reported for P25 TiO2 films deposited as a pristine film on FTO. The pristine P25 films show a photocurrent of 0.06 mA/cm2 and an onset potential of -0.5 V vs. Ag/AgCl. After TiCl4 Treatment to form a compact TiO 2 layer on the bottom and the surface layer, the TiCl4 sandwich films have a photocurrent of 0.19 mA/cm2 and an onset potential of -0.8 V. We have also investigated the effects of hydrogen treatment, ammonia treatment, and the combination of hydrogen treatment followed by ammonia treatment (co-treatment) on the photocurrent, the incident photon-to-current efficiency (IPCE), and the electron donor density of the P25 TiCl4 sandwich films. Treating the P25 films had almost no effect on the size and d-spacing of the particles, but EPR evidence, as well as color change, indicated the formation of N 2p nitrogen sites and oxygen vacancies (VO) for each film treatment. I-V data for the treated TiCl4 sandwich films show an increase in photocurrent from 0.19 mA/cm2 for the pristine P25 TiO2 film to 0.4 mA/cm 2 for the co-treated TiO2 film compared to 0.23 mA/cm 2 for hydrogen treatment and 0.25 mA/cm2 for ammonia treatment. For the P25 treated films, there is negligible increase of UV absorption in the visible for the singly treated films as well as the co-treated films. However, the improved photocurrent for the ammonia treated, hydrogen treated, and co-treated films may be explained by increased donor density. Mott-Schottky plots are used to characterize donor density, showing that the co-treated P25 TiCl4 sandwich films have an increased donor density over the nitrogen-treated P25 TiO2 and pristine P25 TiO2 films. The improved donor density of the treated P25 films over the untreated films may prove to be useful when completing future dye or semiconducting quantum dot sensitization experiments.

  17. Preparation and antimicrobial assay of ceramic brackets coated with TiO2 thin films

    Science.gov (United States)

    Cao, Shuai; Wang, Ye; Cao, Lin; Wang, Yu; Lin, Bingpeng; Lan, Wei

    2016-01-01

    Objective Different methods have been utilized to prevent enamel demineralization and other complications during orthodontic treatment. However, none of these methods can offer long-lasting and effective prevention of orthodontic complications or interventions after complications occur. Considering the photocatalytic effect of TiO2 on organic compounds, we hoped to synthesize a novel bracket with a TiO2 thin film to develop a photocatalytic antimicrobial effect. Methods The sol-gel dip coating method was used to prepare TiO2 thin films on ceramic bracket surfaces. Twenty groups of samples were composed according to the experimental parameters. Crystalline structure and surface morphology were characterized by X-ray diffraction and scanning electron microscopy, respectively; film thickness was examined with a surface ellipsometer. The photocatalytic properties under ultraviolet (UV) light irradiation were analyzed by evaluating the degradation ratio of methylene blue (MB) at a certain time. Antibacterial activities of selected thin films were also tested against Lactobacillus acidophilus and Candida albicans. Results Films with 5 coating layers annealed at 700℃ showed the greatest photocatalytic activity in terms of MB decomposition under UV light irradiation. TiO2 thin films with 5 coating layers annealed at 700℃ exhibited the greatest antimicrobial activity under UV-A light irradiation. Conclusions These results provide promising guidance in prevention of demineralization by increasing antimicrobial activities of film coated brackets. PMID:27226960

  18. A micro oxygen sensor based on a nano sol-gel TiO2 thin film.

    Science.gov (United States)

    Wang, Hairong; Chen, Lei; Wang, Jiaxin; Sun, Quantao; Zhao, Yulong

    2014-09-03

    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 μm × 350 μm 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.

  19. 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 μm × 350 μm 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.

  20. In situ Fenton reagent generated from TiO2/Cu2O composite film: a new way to utilize TiO2 under visible light irradiation.

    Science.gov (United States)

    Zhang, Yong-Gang; Ma, Li-Li; Li, Jia-Lin; Yu, Ying

    2007-09-01

    TiO2/Cu2O composite is prepared by a simple electrochemical method and coated on glass matrix through a spraying method. The obtained composite is characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The effect of TiO2/Cu2O composite films with different ratio of TiO2 and Cu2O on photodegradation of the dye methylene blue under visible light is investigated in detail. It is found that the photocatalytic activity of TiO2/Cu2O composite film with the presence of FeSO4 and EDTA is much higher than that for the similar system with only TiO2 and Cu2O film respectively. Without the presence of FeSO4 and EDTA, there is no degradation for methylene blue. The exploration of the optimized parameters for the degradation of methylene blue by using TiO2/Cu2O composite film as catalyst under visible light was also carried out. The most significant factor is the amount of Ti02 in the composite, and the second significant factor is the concentration of FeSO4. During the degradation of methylene blue under visible light, TiO2/Cu2O composite film generates H202, and Fenton regent is formed with Fe2+ and EDTA, which is detected in this study. The mechanism for the great improvement of photocatalytic activity of TiO2/Cu2O composite film under visible light is proposed by the valence band theory. Electrons excitated from TiO2/Cu2O composite under visible light are transferred from the conduction band of Cu2O to that of Ti02. The formed intermediate state of Ti 3+ ion is observed by X-ray photoelectron spectroscopy (XPS) on the TiO/Cu2O composite film. Additionally, the accumulated electrons in the conduction band of TiO2 are transferred to oxygen on the TiO2 surface for the formation of O2- or O2(2-), which combines with H+ to form H2O2. The evolved H202 with FeSO4 and EDTA forms Fenton reagentto degrade methylene blue. Compared to the traditional Fenton reagent, this new kind of in situ Fenton reagent generated from TiO2/Cu2O composite film does not need to

  1. The Layer Boundary Effect on Multi-Layer Mesoporous TiO2 Film Based Dye Sensitized Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Feng; Zhu, Kai; Zhao, Yixin

    2016-10-01

    Multi-layer mesoporous TiO2 prepared by screen printing is widely used for fabrication of high-efficiency dye-sensitized solar cells (DSSCs). We compare the three types of ~10 um thick mesoporous TiO2 films, which were screen printed as 1-, 2- and 4-layers using the same TiO2 nanocrystal paste. The layer boundary of the multi-layer mesoporous TiO2 films was observed in the cross-section SEM. The existence of a layer boundary could reduce the photoelectron diffusion length with the increase of layer number. However, the photoelectron diffusion lengths of the Z907 dye sensitized solar cells based on these different layered mesoporous TiO2 films are all longer than the film thickness. Consequently, the photovoltaic performance seems to have little dependence on the layer number of the multi-layer TiO2 based DSSCs.

  2. Application of beam irradiation in preparation of visible light responsive TiO2 Films

    Institute of Scientific and Technical Information of China (English)

    HOU Xinggang; LIU Andong

    2007-01-01

    TiO2 films were prepared by sol-gel method.In order to improve the utilization of light, the technologiesof implantation of transition metal ions (V+ and Cr+) and electron beam irradiation to deposit noble metal particles (Ag and Pt) were used. A red shift was found in the spectrum of modified TiO2 films. The photocatalytic experiments showed that the photocatalytic ability under visible light irradiation could be improved dramatically by both the implantation of transition metal and the electron beam irradiation.

  3. Synergetic effect between adsorption and photodegradation on nanostructured TiO2/activated carbon fiber felt porous composites for toluene removal.

    Science.gov (United States)

    Li, Min; Lu, Bin; Ke, Qin-Fei; Guo, Ya-Jun; Guo, Ya-Ping

    2017-03-15

    The low quantum efficiency and limited adsorption efficiency of TiO2 makes it only fit for the removal of VOCs with low concentrations. Herein, we for the first time fabricated nanostructured TiO2/activated carbon fiber felt (TiO2/ACFF) porous composites by the in situ deposition of TiO2 microspheres on the carbon fibers in ACFF. Interestingly, the TiO2 microspheres exhibit hierarchical nanostructures constructed by nanocrystals as building blocks. The TiO2/ACFF porous composites possess excellent adsorption and photodegradation properties for toluene because of the synergetic effects between the nanostructured TiO2 and ACFF. The adsorption efficiencies of the TiO2/ACFF porous composites reach approximately 98% at the toluene concentration (TiO2/ACFF porous composites significantly enhances photocatalytic property for toluene by hindering the recombination of electron-hole pairs, reducing the TiO2 band gap energy (Eg) to 2.95eV and accelerating toluene adsorption. At the toluene concentrations of 230ppm and 460ppm, the photocatalytic oxidation efficiency of toluene into CO2 arrives at 100% and 81.5%, respectively. Therefore, the TiO2/ACFF porous composites with synergetic adsorption and photocatalytic activities have great potentials for toluene removal.

  4. Enhanced photovoltaic properties of dye-sensitized solar cell based on ultrathin 2D TiO2 nanostructures

    Science.gov (United States)

    Zhang, Putao; Hu, Zhiqiang; Wang, Yan; Qin, Yiying; Sun, Xiao Wei; Li, Wenqin; Wang, Jinmin

    2016-04-01

    Ultrathin two-dimensional (2D) TiO2 nanostructures with a thickness of ∼5 nm and a specific surface area of 257.3 m2 g-1 were synthesized by a hydrothermal process. The 2D TiO2 nanostructures and P25 nanoparticles were introduced as scattering layer and underlayer to construct a bi-layer photoanode in a dye-sensitized solar cell (DSSC). The as-prepared DSSC exhibits an enhanced power conversion efficiency (5.14%), which is 23.9% higher than that of pure P25 DSSC (4.15%). Electrochemical impedance spectroscopy (EIS) indicates that DSSC based on P25-2D TiO2 nanostructures shows a longer life time and a larger recombination resistance. The enhanced photovoltaic properties are attributed to the excellent light scattering capability and high capacity for dye adsorption of 2D TiO2 nanostructures, which makes them a promising candidate as an efficient scattering layer in high-performance DSSCs.

  5. TiO2 Thin Film via Sol-Gel Method: Investigation on Molarity Effect

    Science.gov (United States)

    Mohamad Saad, Puteri Sarah; Sutan, Hanis Binti; Sobihana Shariffudin, Shafinaz; Hashim, Hashimah; Mohd Noor, Uzer

    2015-11-01

    We have systematically investigated the current-voltage (I-V), absorbance and optical band gap of TiO2 thin film prepared through varying the molarity of the TiO2 precursor by sol-gel spin coating technique. In addition to the electrical and optical characteristics, the surface morphology was examined by using Atomic Force Microscope (AFM). From the image of the AFM, we were able to observe the uniformity of the TiO2 thin film. From the experimental results, we found that the uniformity of the TiO2 thin film is optimized at 0.2M sample. It is also found that, as the molarity increased, there is tendency of the resistivity to decrease. Not only that, the absorbance measurement and optical band gap also gave its best value for 0.2M sample. Therefore, in this work it is concluded that 0.20M of TiO2 gave the best characteristics for all measurements.

  6. Surface-area-controlled synthesis of porous TiO2 thin films for gas-sensing applications

    Science.gov (United States)

    Park, Jae Young; Kim, Ho-hyoung; Rana, Dolly; Jamwal, Deepika; Katoch, Akash

    2017-03-01

    Surface-area-controlled porous TiO2 thin films were prepared via a simple sol–gel chemical route, and their gas-sensing properties were thoroughly investigated in the presence of typical oxidizing NO2 gas. The surface area of TiO2 thin films was controlled by developing porous TiO2 networked by means of controlling the TiO2-to-TTIP (titanium isopropoxide, C12H28O4Ti) molar ratio, where TiO2 nanoparticles of size ∼20 nm were used. The sensor’s response was found to depend on the surface area of the TiO2 thin films. The porous TiO2 thin-film sensor with greater surface area was more sensitive than those of TiO2 thin films with lesser surface area. The improved sensing ability was ascribed to the porous network formed within the thin films by TiO2 sol. Our results show that surface area is a key parameter for obtaining superior gas-sensing performance; this provides important guidelines for preparing and using porous thin films for gas-sensing applications.

  7. Surface-area-controlled synthesis of porous TiO2 thin films for gas-sensing applications.

    Science.gov (United States)

    Park, Jae Young; Kim, Ho-Hyoung; Rana, Dolly; Jamwal, Deepika; Katoch, Akash

    2017-03-03

    Surface-area-controlled porous TiO2 thin films were prepared via a simple sol-gel chemical route, and their gas-sensing properties were thoroughly investigated in the presence of typical oxidizing NO2 gas. The surface area of TiO2 thin films was controlled by developing porous TiO2 networked by means of controlling the TiO2-to-TTIP (titanium isopropoxide, C12H28O4Ti) molar ratio, where TiO2 nanoparticles of size ∼20 nm were used. The sensor's response was found to depend on the surface area of the TiO2 thin films. The porous TiO2 thin-film sensor with greater surface area was more sensitive than those of TiO2 thin films with lesser surface area. The improved sensing ability was ascribed to the porous network formed within the thin films by TiO2 sol. Our results show that surface area is a key parameter for obtaining superior gas-sensing performance; this provides important guidelines for preparing and using porous thin films for gas-sensing applications.

  8. 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 %.

  9. Photocatalytic Activity of Toluene under UV-LED Light with TiO2 Thin Films

    Directory of Open Access Journals (Sweden)

    Thammasak Rojviroon

    2012-01-01

    Full Text Available Titanium dioxide (TiO2 and ferric-doped TiO2 (Fe-TiO2 thin films were synthesized on the surface of 304 stainless steel sheets using a simplified sol-gel preparation method. The Fe-TiO2 thin films were prepared with weight-to-volume ratios of /TiO2 of 0.3%, 0.5%, and 0.7%, respectively. The crystalline phase structures of the prepared TiO2 and Fe-TiO2 thin films were entirely anatase. The measured optical band gaps of the TiO2, 0.3% Fe-TiO2, 0.5% Fe-TiO2, and 0.7% Fe-TiO2 thin films were 3.27, 3.28, 3.22, and 2.82 eV, respectively. The grain sizes and other physical properties of the prepared thin films were also reported. The kinetics of the photocatalytic processes under a UV-LED light source could be explained by the Langmuir-Hinshelwood kinetic model with the specific rates of , , , and  , for TiO2, 0.3% Fe-TiO2, 0.5% Fe-TiO2, and 0.7% Fe-TiO2, respectively. An increase in dopant concentration could enhance the photocatalytic activity of toluene decomposition as a result of lower optical band gaps, smaller grain size, and higher surface area.

  10. Corrosion Behavior of Anodic Oxidized TiO2 Film in Seawater

    Institute of Scientific and Technical Information of China (English)

    WANG Min; WANG Wei; HE Benlin; SUN Mingliang; YIN Yansheng; LIU Lan; ZOU Wuyuan; XU Xuefei

    2010-01-01

    TiO2 films were formed on metallic titanium substrates by the anodic oxidation method in H2SO4 solution under the 80V D.C..Phase component and microstructure were characterized by X-ray diffraction(XRD)and scanning electron microscopy(SEM).Water contact angles on titanium oxide film surface were measured under both dark and sunlight illumination conditions.Corrosion tests were carried out in seawater under different illumination conditions by electrochemistry impedance spectrum(EIS)and polarization curves.The result showed that the TiO2 film prepared by the anodic oxidation method was anatase with a uniform structure and without obvious pores or cracks on its surface.The average water contact angle of the film was 116.4 ° in dark,in contrast to an angle of 42.7 ° under the UV illumination for 2 hours,which demonstrates good hydrophobic property.The anti-corrosion behavior of the TiO2 film was declining with the extended immersion time.Under dark conditions,however,the hydrophobic TiO2 film retarded the water infiltrating into the substrate.The impedance changed slowly and the corrosion current density was 2 orders of magnitude lower than that with the film illuminated by sunlight.All of those mentioned above indicate that the TiO2 film possesses much better performance under dark condition,and it can be applied as an engineering material under dark seawater environment.

  11. Responding Depth of Photocatalytic Activity of TiO2 Self-assembled Films

    Institute of Scientific and Technical Information of China (English)

    Weichang HAO; Feng PAN; Tianmin WANG; Shukai ZHENG

    2004-01-01

    The electrostatically self-assembly method is getting strategically important to prepare multilayer thin films. With careful choice of component materials, this method should allow for the preparation of multilayer thin films with a variety of excellent technological properties. TiO2/PSS multilayer thin films with ordered structure were prepared by electrostatic self-assembly method. UV-Vis-NIR spectrophotometer, X-ray photoelectron spectroscopy (XPS),and atom force microscopy (AFM) were used to characterize the structure and performance of the multilayer films.Because electrostatically self-assembly method allows molecular-level control over the film composition and thickness,this paper studied the responding depth of photocatalytic activity of TiO2 self-assembled films in detail.

  12. Transparent thin-film TiO2 photocatalysts with high activity.

    Science.gov (United States)

    Blount, M C; Kim, D H; Falconer, J L

    2001-07-15

    A transparent, thin-film TiO2 layer prepared by sol-gel deposition is shown to be more active for photocatalytic oxidation (PCO) of acetaldehyde, acetic acid, and toluene than Degussa P25 thin films. The sol-gel TiO2 adsorbs 30-70% less organic, but the PCO activity per adsorbed molecule is 3.5-8.5 times higher on the sol-gel TiO2 than on Degussa P25. In addition, less-reactive intermediates do not appear to form as readily on the sol-gel catalyst as they do on Degussa P25, and thus the sol-gel catalyst deactivates slower during toluene PCO. Rates were measured in transient experiments for a monolayer of adsorbed organic, and transient experiments are shown to be an effective way to measure rates, selectivities, surface coverages, and formation of less-reactive intermediates in the same set of experiments.

  13. C ion-implanted TiO2 thin film for photocatalytic applications

    Science.gov (United States)

    Impellizzeri, G.; Scuderi, V.; Romano, L.; Napolitani, E.; Sanz, R.; Carles, R.; Privitera, V.

    2015-03-01

    Third-generation TiO2 photocatalysts were prepared by implantation of C+ ions into 110 nm thick TiO2 films. An accurate structural investigation was performed by Rutherford backscattering spectrometry, secondary ion mass spectrometry, X-ray diffraction, Raman-luminescence spectroscopy, and UV/VIS optical characterization. The C doping locally modified the TiO2 pure films, lowering the band-gap energy from 3.3 eV to a value of 1.8 eV, making the material sensitive to visible light. The synthesized materials are photocatalytically active in the degradation of organic compounds in water under both UV and visible light irradiation, without the help of any additional thermal treatment. These results increase the understanding of the C-doped titanium dioxide, helpful for future environmental applications.

  14. Bacteria-directed construction of hollow TiO2 micro/nanostructures with enhanced photocatalytic hydrogen evolution activity.

    Science.gov (United States)

    Zhou, Han; Fan, Tongxiang; Ding, Jian; Zhang, Di; Guo, Qixin

    2012-03-12

    A general method has been developed for the synthesis of various hollow TiO2 micro/nanostructures with bacteria as templates to further study the structural effect on photocatalytic hydrogen evolution properties. TiO2 hollow spheres and hollow tubes, served as prototypes, are obtained via a surface sol-gel process using cocci and bacillus as biotemplates, respectively. The formation mechanisms are based on absorption of metal-alkoxide molecules from solution onto functional cell wall surfaces and subsequent hydrolysis to give nanometer-thick oxide layers. The UV-Vis absorption spectrum shows that the porous TiO2 hollow spheres have enhanced light harvesting property compared with the corresponding solid counterpart. This could be attributed to their unique hollow porous micro/nanostructures with microsized hollow cavities and nanovoids which could bring about multiple scattering and rayleigh scattering of light, respectively. The hollow TiO2 structures exhibit superior photocatalytic hydrogen evolution activities under UV and visible light irradiation in the presence of sacrificial reagents. The hydrogen evolution rate of hollow structures is about 3.6 times higher than the solid counterpart and 1.5 times higher than P25-TiO2. This work demonstrates the structural effect on enhancing the photocatalytic hydrogen evolution performance which would pave a new pathway to tailor and improve catalytic properties over a broad range.

  15. Effect of Au clustering on ferromagnetism in Au doped TiO2 films: theory and experiments investigation

    Science.gov (United States)

    Zou, Zhaorui; Zhou, Zhongpo; Wang, Haiying; Yang, Zongxian

    2017-01-01

    In this paper, we investigated the physical properties especially the magnetic properties of the TiO2 films and Au cluster doped TiO2 films fabricated by sol-gel and sputtering methods combined experiments and first-principles calculations. All the samples annealed under air and N2 atmosphere respectively exhibit room temperature ferromagnetism with the crystal phase of anatase. The values of the saturation magnetizations are in the order of Au δ-doped TiO2 (annealed in N2)>undoped TiO2 (annealed in air)>Au δ-doped TiO2 (annealed in air). The first principles calculation results show that the formation energy of Au cluster doped TiO2 films is lower than that of the oxygen vacancy and Au cluster codoped TiO2 films. The effects of the Au cluster dopant are the retard of the formation of surface oxygen vacancy and the electrons transfer from 3d states of Ti atoms to Au 5d states in Au cluster doped TiO2 films. The codoping of surface oxygen vacancies, bulk oxygen vacancies and Au clusters led to the spin-split of Ti 3d and O 2p in Au cluster doped TiO2 films (annealed in N2) which yield the highest saturation magnetization.

  16. PbO-modified TiO2 thin films: a route to visible light photocatalysts.

    Science.gov (United States)

    Bhachu, Davinder S; Sathasivam, Sanjayan; Carmalt, Claire J; Parkin, Ivan P

    2014-01-21

    PbO clusters were deposited onto polycrystalline titanium dioxide (anatase) films on glass substrates by aerosol-assisted chemical vapor deposition (AACVD). The as-deposited PbO/TiO2 films were then tested for visible light photocatalysis. This was monitored by the photodegradation of stearic acid under visible light conditions. PbO/TiO2 composite films were able to degrade stearic acid at a rate of 2.28 × 10(15) molecules cm(-2) h(-1), which is 2 orders of magnitude greater than what has previously been reported. The PbO/TiO2 composite film demonstrated UVA degradation of resazurin redox dye, with the formal quantum yield (FQY) and formal quantum efficiency (FQE) exceeding that of a TiO2 film grown under the same conditions and Pilkington Activ, a commercially available self-cleaning glass. This work correlates with computational studies that predicted PbO nanoclusters on TiO2 form active visible light photocatalysts through new electronic states through PbO/TiO2 interfacial bonds resulting in new electronic states above the valence band maximum in TiO2, shifting the valence band upward as well as more efficient electron/hole separation with hole localization on PbO particles and electron on the TiO2 surface.

  17. Fe-Doped TiO2 Thin Films for CO Gas Sensing

    Science.gov (United States)

    Kumar, Mukesh; Kumar, Dinesh; Gupta, Anil Kumar

    2015-01-01

    Fe-doped TiO2 thin films were prepared by the sol-gel technique on silicon substrate. The thin films were evaluated for detection of carbon monoxide (CO) gas at room temperature. The TiO2 films were characterized by x-ray diffraction (XRD) analysis, field-emission scanning electron microscopy, and ultraviolet-visible (UV) spectroscopy. The characterization revealed that, as the doping concentration was increased, the grain size decreased. XRD patterns revealed the phase transition from rutile to anatase with addition of different percentages (weight/volume) of Fe. The bandgap determined from UV spectroscopy was found to decrease with increasing Fe doping concentration. Fe doping was observed to have a significant effect on the resistivity of the doped TiO2 thin films. The gas sensing behavior of the films was studied by exposure to different concentrations of CO gas with measurement of the electrical resistance. It was observed that Fe-doped (7% weight/volume) TiO2 exhibited high sensitivity and good response/recovery on exposure to CO gas in the concentration range from 100 ppm to 900 ppm in Ar.

  18. Fabrication and Photocatalytic Characteristics of TiO2 Films on Silicon Substrates

    Institute of Scientific and Technical Information of China (English)

    YANG Jia-long; WANG Fu; ZUO Liang; YI Gu-chul; CHOI Wong-yong

    2005-01-01

    Silicon (111) and Silicon (100) have been employed for fabrication of TiO2 films by metal organic chemical vapor deposition (MOCVD). Titanium (Ⅳ) isopropoxide (Ti[O(C3H7)4]) was used as a precursor. The as-deposited TiO2 films have been characterized with Field emission scanning electron microscopy(FE-SEM), X ray diffraction (XRD) and atomic force microscopy (AFM). The photocatalytic properties were investigated by decomposition of aqueous orange Ⅱ. The crystalline and structural properties of TiO2 film had crucial influences on the photodegradation efficiency. For MOCVD in-situ deposited films on Si substrates, the photoactivities varied following a shape of "M": At lower (350 ℃) middle (500 ℃) and higher (800 ℃) temperature of deposition, relative lower photodegradation activities have been observed. At 400 ℃ and 700 ℃ of deposition, relative higher efficiencies of degradation have been obtained, because one predominant crystallite orientation could be obtained as deposition at those two temperatures, especially a single anatase crystalline TiO2 film could be obtained at 700 ℃ growth.

  19. Synthesis, Characterization and Photocatalytic Activity of TiO2 Film/Bi2O3 Microgrid Heterojunction

    Institute of Scientific and Technical Information of China (English)

    Liugang Wang; Junying Zhang; Chunzhi Li; Hailing Zhu; Wenwen Wang; Tianmin Wang

    2011-01-01

    TiO2 film modified by Bi2O3 microgrid array was successfully fabricated by using a microsphere lithography method. The structure and morphology of TiO2 film, Bi2O3 film and TiO2 film/Bi2O3 microgrid heterojunction were characterized through X-ray diffraction, atomic force microscopy and scanning electron microscopy. The optical transmittance spectra and the photocatalytic degradation capacity of these samples to rhodamine B were determined via ultraviolet-visible spectroscopy. The results indicated that the coupled system showed higher photocatalytic activity than pure TiO2 and Bi2O3 films under xenon lamp irradiation. The enhancement of the photocatalytic activity was ascribed to the special structure, which could improve the separation of photo-generated electrons and holes, enlarge the surface area and extend the response range of TiO2 film from ultraviolet to visible region.

  20. Effect of SiO2 addition on photocatalytic activity, water contact angle and mechanical stability of visible light activated TiO2 thin films applied on stainless steel by a sol gel method

    Science.gov (United States)

    Momeni, Mansour; Saghafian, Hasan; Golestani-Fard, Farhad; Barati, Nastaran; Khanahmadi, Amirhossein

    2017-01-01

    Nanostructured N doped TiO2/20%SiO2 thin films were developed on steel surface via sol gel method using a painting airbrush. Thin films then were calcined at various temperatures in a range of 400-600 °C. The effect of SiO2 addition on phase composition and microstructural evolution of N doped TiO2 films were studied using XRD and FESEM. Optical properties, visible light photocatalytic activity, hydrophilic behavior, and mechanical behavior of the films were also investigated by DRS, methylene blue degradation, water contact angle measurements, and nanoscratch testing. Results indicated that the band gap energy of N doped TiO2/SiO2 was increased from 2.93 to 3.09 eV. Crack formation during calcination was also significantly promoted in the composite films. All composite films demonstrated weaker visible light photocatalytic activities and lower mechanical stability in comparison with N doped TiO2 films. Moreover, the N doped TiO2/SiO2 film calcined at 600 °C showed undesirable hydrophilic behavior with a water contact angle of 57° after 31 h of visible light irradiation. Outcomes of the present study reveal some different results to previous reports on TiO2/SiO2 films. In general, we believe the differences in substrate material as well as application in visible light are the main reasons for the above mentioned contradiction.

  1. Optical and Morphological Properties of ZnO- and TiO2-Derived Nanostructures Synthesized via a Microwave-Assisted Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Nosipho Moloto

    2012-01-01

    Full Text Available A microwave-assisted hydrothermal method was used to synthesize ZnO and TiO2 nanostructures. The experimental results show that the method resulted in crystalline monodispersed ZnO nanorods that have pointed tips with hexagonal crystal phase. TiO2 nanotubes were also formed with minimum bundles. The mechanism for the formation of the tubes was validated by HRTEM results. The optical properties of both ZnO and TiO2 nanostructures showed characteristics of strong quantum confinement regime. The photoluminescence spectrum of TiO2 nanotubes shows good improvement from previously reported data.

  2. A versatile new method for synthesis and deposition of doped, visible light-activated TiO2 thin films

    DEFF Research Database (Denmark)

    In, Su-il; Kean, A.H.; Orlov, A.

    2009-01-01

    A flexible and widely applicable method allows the deposition of carbon-doped visible light-activated photocatalytic TiO2 thin films on a variety of substrates.......A flexible and widely applicable method allows the deposition of carbon-doped visible light-activated photocatalytic TiO2 thin films on a variety of substrates....

  3. Superior electrode performance of mesoporous hollow TiO2 microspheres through efficient hierarchical nanostructures

    Science.gov (United States)

    Zhang, Feng; Zhang, Yu; Song, Shuyan; Zhang, Hongjie

    2011-10-01

    Mesoporous hollow TiO2 microspheres with controlled size and hierarchical nanostructures are designed from a process employing in suit template-assisted and hydrothermal methods. The results show that the hollow microspheres composed of mesoporous nanospheres possess very stable reversible capacity of 184 mAh g-1 at 0.25C and exhibit extremely high power of 122 mAh g-1 at the high rate of 10C. The superior high-rate and high-capacity performance of the sample is attributed to the efficient hierarchical nanostructures. The hollow structure could shorten the diffusion length for lithium ion in the microspheres. The large mesoporous channels between the mesoporous nanospheres provide an easily-accessed system which facilitates electrolyte transportation and lithium ion diffusion within the electrode materials. The electrolyte, flooding the mesoporous channels, can also lead to a high electrolyte/electrode contact area, facilitating transport of lithium ions across the electrolyte/electrode interface. The small mesopores in the meosporous nanospheres can make the electrolyte and lithium ion further diffuse into the interior of electrode materials and increase electrolyte/electrode contact area. The small nanoparticles can also ensure high reversible capacity.

  4. Effects of mineral tourmaline particles on the photocatalytic activity of TiO2 thin films.

    Science.gov (United States)

    Meng, Junping; Liang, Jinsheng; Ou, Xiuqin; Ding, Yan; Liang, Guangchuan

    2008-03-01

    Titania composite thin films (T/TiO2) containing tourmaline particles were prepared by a sol-gel method, using alkoxide solutions as precursor. The tourmaline particles and thin films were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and so on. The effects of tourmaline on the photocatalytic activity of TiO2 were measured with methyl orange as an objective photodegradation substance. The results showed that the photocatalytic degradation of methyl orange conformed to the first-order kinetic equation and the composite thin films had better photocatalytic activity due to the cooperation of polarity and the far infrared emission of tourmaline. The T/TiO2 thin films including 0.5 wt% tourmaline exhibited better photocatalytic activity when heat-treated at 250 degrees C for 3 h, than pure TiO2 thin films under the ultraviolet irradiation.

  5. Preparation of Ag-doped TiO2 Thin Film by Sol-gel Method

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The Ag-TiO2 thin film has been prepared on glass substrate by sol-gel process. The structure and properties of the materials were studied by DTA, XRD, and EPR.The photocatalytic activity was examined by the photocatalytic degradation of dichlorophos. The analysis results indicate that the photocatalytic activity of the Ag-TiO2 thin film is higher than that of pure TiO2 thin film. It is also influenced by the content of anatase and heating temperature. The ESR result shows that the Ag-TiO2 thin film has more hydroxide radicals than pure TiO2 thin film after illuminated by UV light.

  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. Atomic Force Microscopy Studies on the Chemical Treatment of Nanocrystalline Porous TiO2 Films

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    AFM has been utilized to study the surface topography and the local conductivity of nanocrystalline TiO2 films. Improving the local conductivity by Ti(iso-C3H7O)4 treatment is characterized by quantitative analysis of the simultaneous current image. The mechanism of Ti(iso C3H7O)4 treatment is discussed.

  8. Tunability of morphological properties of Nd-doped TiO2 thin films

    Science.gov (United States)

    Saleem Bhatti, Arshad; Rehan, Imran; Sultana, Sabiha; Khan, Nauman; Qamar, Zahid; Rehan, Kamran

    2016-11-01

    In this work, an endeavor is made toward structural assessment and morphological variation of titanium dioxide (TiO2) thin films when doped with neodymium (Nd). The electron beam deposition technique was employed to fabricate Nd-based TiO2 thin films on n-Type Si substrates. Nd concentration was varied from 0.0 to 2.0 atomic percent (at.%) under identical growth environments. The films were deposited in an oxygen-deficient environment to cause the growth of rutile phases. Energy dispersive x-ray spectroscopy confirmed the presence and variation of Nd dopant in TiO2. X-ray diffraction analysis showed the transformation of amorphous structures of the as-grown samples to anatase polycrystalline after annealing at 500 °C, while atomic force microscopy exposed linearity in grain density in as-grown samples with doping until 1 at.%. Raman spectrums of as-grown and annealed samples revealed the growth of the anatase phase in the annealed samples. Based on these results it can be proposed that Nd doping has pronounced effects on the structural characteristics of TiO2 thin films.

  9. Disinfection studies on TiO2 thin films prepared by a sol-gel method.

    Science.gov (United States)

    Kambala, Venkata Subba Rao; Naidu, Ravi

    2009-02-01

    Transparent anatase TiO2 nanometer thin films were prepared by dip-coating on soda-lime glass plates via the sol-gel method. The un-calcined and the calcined films were characterized by X-ray diffraction (XRD), AFM, Nano-indentation (hardness and Young's modulus), UV-vis spectrometry, thickness and hydrophilicity (contact angle measurements). The photocatalytic activity of the thin films was evaluated by performing disinfection studies on the Gram-negative microorganisms like Escherichia coli, and Staphylococcus Aureus, a Gram-positive organism. The photocatalytic activity for both groups of organisms was studied in saline and nutrient broth. The leakage of potassium from the bacteria was observed parallel to cell viability. The activity of the sol-gel prepared TiO2 thin films were compared under UV lamps and natural day light (ND) lamps with Degussa P-25 TiO2 thin films prepared on soda-lime glass using a polymer support and the commercial self-cleaning glass (SC). The sol-gel prepared thin films which were annealed at 450 degrees C, show highest photocatalytic activity, the slowest conversion rate from hydrophilic to a hydrophobic state, light-induced hydrophilicity, and also higher disinfection activities compared to P-25 films and commercial self-cleaning glass. The films also show excellent activities when continuously reused for more than a month.

  10. Photodegradation of Azo-dye by Y2O3/TiO2 Loaded on Carboxymethyl Cellulose Films

    Institute of Scientific and Technical Information of China (English)

    HE Xiao-yun; CHEN Ri-yao; ZHENG Xi; CHEN Zhen

    2005-01-01

    Nanosize TiO2, Y2 O3/TiO2 particles were prepared by the sol-gel process. The structure was characterized by means of XRD,TEM. The photoelectric properties of the nanoparticles were studied by PL.The thickness and the surface of the carboxymethyl cellulose film was measured by SEM. Based on a model reaction, the photocatalytic degradation of methylene blue with positive charge was investigated in TiO2,Y2O3/TiO2 nanopowder composite films irradiated by UV lamp. The results revealed that the degradation process belonged to the first-order kinetic reaction.

  11. Photocatalytic performance of TiO2 immobilized on polystyrene (PS) thin film for mineralization of pollutants

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A new photocatalyst, TiO2 powder immobilized on polystyrene (PS) thin films, was prepared using a novelmethod and its photocatalytic activity on the photodegradation of acridine dye in aqueous solution was tested. By thismethod, the crystal form and grain size of the immobilized TiO2 were well maintained. Compared with TiO2 powder, thephotocatalytic activity of TiO2/PS thin films was not significantly reduced. The catalyst is stable and can be reused severaltimes without the loss of activity, which makes wastewater treatment using this photocatalytic degradation technique of thisway possible in the practical application.

  12. Flame-Made Pt-Loaded TiO2 Thin Films and Their Application as H2 Gas Sensors

    Directory of Open Access Journals (Sweden)

    Weerasak Chomkitichai

    2013-01-01

    Full Text Available The hydrogen gas sensors were developed successfully using flame-made platinum-loaded titanium dioxide (Pt-loaded TiO2 nanoparticles as the sensing materials. Pt-loaded TiO2 thin films were prepared by spin-coating technique onto Al2O3 substrates interdigitated with Au electrodes. Structural and gas-sensing characteristics were examined by using scanning electron microscopy (SEM and showed surface morphology of the deposited film. X-ray diffraction (XRD patterns can be confirmed to be the anatase and rutile phases of TiO2. High-resolution transmission electron microscopy (HRTEM showed that Pt nanoparticles deposited on larger TiO2 nanoparticles. TiO2 films loaded with Pt nanoparticles were used as conductometric sensors for the detection of H2. The gas sensing of H2 was studied at the operating temperatures of 300, 350, and 400°C in dry air. It was found that 2.00 mol% Pt-loaded TiO2 sensing films showed higher response towards H2 gas than the unloaded film. In addition, the responses of Pt-loaded TiO2 films at all operating temperatures were higher than that of unloaded TiO2 film. The response increased and the response time decreased with increasing of H2 concentrations.

  13. Cytotoxicity Evaluation of Anatase and Rutile TiO2 Thin Films on CHO-K1 Cells in Vitro

    Directory of Open Access Journals (Sweden)

    Blanca Cervantes

    2016-07-01

    Full Text Available Cytotoxicity of titanium dioxide (TiO2 thin films on Chinese hamster ovary (CHO-K1 cells was evaluated after 24, 48 and 72 h of culture. The TiO2 thin films were deposited using direct current magnetron sputtering. These films were post-deposition annealed at different temperatures (300, 500 and 800 °C toward the anatase to rutile phase transformation. The root-mean-square (RMS surface roughness of TiO2 films went from 2.8 to 8.08 nm when the annealing temperature was increased from 300 to 800 °C. Field emission scanning electron microscopy (FESEM results showed that the TiO2 films’ thickness values fell within the nanometer range (290–310 nm. Based on the results of the tetrazolium dye and trypan blue assays, we found that TiO2 thin films showed no cytotoxicity after the aforementioned culture times at which cell viability was greater than 98%. Independently of the annealing temperature of the TiO2 thin films, the number of CHO-K1 cells on the control substrate and on all TiO2 thin films was greater after 48 or 72 h than it was after 24 h; the highest cell survival rate was observed in TiO2 films annealed at 800 °C. These results indicate that TiO2 thin films do not affect mitochondrial function and proliferation of CHO-K1 cells, and back up the use of TiO2 thin films in biomedical science.

  14. Preparation and Photocatalytic Application of High Temperature Stabilized ZrSiO4@TiO2 Hybrid Nanostructure

    Institute of Scientific and Technical Information of China (English)

    PENG Cheng; FANG Peiyu; ZENG Zhichao; Lü Ming; WU Jianqing

    2014-01-01

    A new ZrSiO4@TiO2 hybrid nanostructure was prepared by a heterogeneous flocculation method. Phytic acid was introduced to modify the surface charging of the components for hybrid assembly. The obtained powder was coated on ceramic tiles and fired at 900 ℃ to fabricate photocatalytic ceramic. Experimental results show that anatase TiO2 in the composite powder has high thermal stability until 1 200℃. ZrSiO4 matrix prevents the mass transfer of anatase TiO2 at high temperature and greatly retards the phase transition of anatase to rutile. Besides, the photocatalytic ceramic shows apparent activities for the degradation of methyl orange under ultra-violet irradiation.

  15. Surface Microstructure Characterization of Sol-gel Derived Porous TiO2 Thin Films

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Porous TiO2 thin films were prepared from alkoxide solutions with and without polyethylene glycol (PEG) by sol-gel route on soda lime glass, and were characterized by atomic force microscopy (AFM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The results show that TiO2 film prepared from precursor solution without PEG is composed of spherical particles of about 100 nm and several nanometer mesoporous pores. With the increase of the amount of PEG added to the precursor solution, the diameter and the depth of the pores in the resultant films increas on the decomposition of PEG during heat-treatment, which lead to the increase of the surface roughness of the films. XRD and TEM results show that the single anatase phase is precipitated and there are some orientation effects in (101) direction.

  16. Synthesis of ultrathin TiO2/Ti films with tunable structural color.

    Science.gov (United States)

    Wang, Yanlu; Han, Rushuai; Qi, Liqian; Liu, Lihu; Sun, Huiyuan

    2016-12-10

    A series of ultrathin TiO2/Ti films with iridescent structural colors were fabricated on high-purity titanium sheets via a one-step anodization procedure. Tunable color in the films can be obtained by adjusting the anodization time and can be adjusted across the entire visible range. It was found that all the films displayed highly saturated colors. Trichromatic coordinates of color x, y were delineated, and the color was identified by positioning the x and y values in the Commission International de I'Eclairage chromaticity diagram. Theoretical and experimental results of the changes in the structural color according to the principle of complementary colors are consistent with the experimental results. The TiO2/Ti films may have potential in color displays, decoration, and anticounterfeiting technology.

  17. Photocatalysts of Cr Doped TiO2 Film Prepared by Micro Arc Oxidation

    Institute of Scientific and Technical Information of China (English)

    Li Wan; Jian-feng Li; Jia-you Feng; Wei Sun; Zong-qiang Mao

    2008-01-01

    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.

  18. Photolithographically Patterned TiO2 Films for Electrolyte-Gated Transistors.

    Science.gov (United States)

    Valitova, Irina; Kumar, Prajwal; Meng, Xiang; Soavi, Francesca; Santato, Clara; Cicoira, Fabio

    2016-06-15

    Metal oxides constitute a class of materials whose properties cover the entire range from insulators to semiconductors to metals. Most metal oxides are abundant and accessible at moderate cost. Metal oxides are widely investigated as channel materials in transistors, including electrolyte-gated transistors, where the charge carrier density can be modulated by orders of magnitude upon application of relatively low electrical bias (2 V). Electrolyte gating offers the opportunity to envisage new applications in flexible and printed electronics as well as to improve our current understanding of fundamental processes in electronic materials, e.g. insulator/metal transitions. In this work, we employ photolithographically patterned TiO2 films as channels for electrolyte-gated transistors. TiO2 stands out for its biocompatibility and wide use in sensing, electrochromics, photovoltaics and photocatalysis. We fabricated TiO2 electrolyte-gated transistors using an original unconventional parylene-based patterning technique. By using a combination of electrochemical and charge carrier transport measurements we demonstrated that patterning improves the performance of electrolyte-gated TiO2 transistors with respect to their unpatterned counterparts. Patterned electrolyte-gated (EG) TiO2 transistors show threshold voltages of about 0.9 V, ON/OFF ratios as high as 1 × 10(5), and electron mobility above 1 cm(2)/(V s).

  19. Comparison of photocatalytic and transport properties of TiO2 and ZnO nanostructures for solar-driven water splitting

    OpenAIRE

    Saracco, Guido; Cauda, Valentina Alice; Lamberti, Andrea; Chiodoni, Angelica; Sacco, Adriano; Hidalgo Diaz, Diana Carolina; Hernandez Ribullen, Simelys Pris; Tresso, Elena Maria

    2015-01-01

    Titanium dioxide (TiO2) and zinc oxide (ZnO) nanostructures have been widely used as photo-catalysts due to their low-cost, high surface area, robustness, abundance and non-toxicity. In this work, four TiO2 and ZnO - based nanostructures, i.e. TiO2 nanoparticles (TiO2 NPs), TiO2 nanotubes (TiO2 NTs), ZnO nanowires (ZnO NWs) and ZnO@TiO2 core-shell structures, specifically prepared with a fixed thickness of about 1.5 μm, are compared for the solar-driven water splitting reaction, under AM1.5G ...

  20. Enhanced thermo-mechanical performance and strain-induced band gap reduction of TiO2@PVC nanocomposite films

    Indian Academy of Sciences (India)

    Mudassir Hasan; Arghya Narayan Banerjee; Moonyong Lee

    2015-04-01

    The present paper reports the fabrication of TiO2@PVC nanocomposites by incorporating TiO2 in polyvinyl chloride (PVC) followed by solution casting to prepare TiO2@PVC nanocomposite thin films. The asprepared TiO2@PVC nanocomposite films were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, high-resolution transmission electron microscopy, thermogravimetric analysis, optical spectroscopy and mechanical strength analyses. The TiO2@PVC nanocomposites were found to be thermally and mechanically more stable compared with pure PVC. The anatase TiO2 in the TiO2@PVC nanocomposite showed a lower indirect band gap compared with pure TiO2, which can be attributed to the strain within the nanocomposite, thereby affecting the band-structure of the nanocomposite. Significant enhancement in the mechanical properties of TiO2@PVC compared with pure PVC was observed with a 10 wt% TiO2 loading, such as a 50% increase in Young's modulus and almost 100% improvement in the tensile strength.

  1. Quantum confinement in amorphous TiO(2) films studied via atomic layer deposition.

    Science.gov (United States)

    King, David M; Du, Xiaohua; Cavanagh, Andrew S; Weimer, Alan W

    2008-11-05

    Despite the significant recent increase in quantum-based optoelectronics device research, few deposition techniques can reliably create the required functional nanoscale systems. Atomic layer deposition (ALD) was used here to study the quantum effects attainable through the use of this ångström-level controlled growth process. Size-dependent quantum confinement has been demonstrated using TiO(2) layers of nanoscale thickness applied to the surfaces of silicon wafers. TiO(2) films were deposited at 100 °C using TiCl(4) and H(2)O(2) in a viscous flow ALD reactor, at a rate of 0.61 Å/cycle. The low-temperature process was utilized to guarantee the amorphous deposition of TiO(2) layers and post-deposition thermal annealing was employed to promote crystallite-size modification. Hydrogen peroxide significantly reduced the residual chlorine that remained from a typical TiCl(4)-H(2)O ALD process at this temperature, down to 1.6%. Spectroscopic ellipsometry was used to quantify the optical properties both below and above the bandgap energy. A central composite design was employed to map the surface response of the film thickness-dependent bandgap shift for the as-deposited case and up to a thermal annealing temperature of 550 °C. The Brus model was used to develop a correlation between the amorphous TiO(2) film thickness and the quantum length to promote equivalent bandgap shifts.

  2. Ti K-edge X-ray absorption spectra of spray pyrolysis synthesized TiO2-x and TiO2-x Nx thin films

    Science.gov (United States)

    Sahoo, Madhusmita; Yadav, Ashok Kumar; Jha, S. N.; Bhattacharyya, Dibyendu; Mathews, Tom; Dash, S.

    2017-05-01

    Oxygen deficient TiO2 and N-TiO2 anatase thin films were synthesized by employing a two step process. First TiO2 and N-TiO2 films were synthesized by using a cost effective spray pyrolysis method. Subsequently, these films were reduced under H2 to create oxygen vacancies. Formation of oxygen vacancies was confirmed by using synchrotron source X-ray Absorption Spectroscopy (XAS). Effect of oxygen vacancies on electronic and structural properties were deduced from the near edge and extended region analysis of the X-ray absorption spectra. It is inferred that reduction time plays a crucial role in creating oxygen vacancies and number of oxygen vacancies increases with increase in reduction time. Substrate effect was delineated by using Si and FTO (Fluorine doped tin oxide coated glass) as substrates for film deposition.

  3. Heterogeneous photocatalytic decomposition of benzene on lanthanum-doped TiO2 film at ambient temperature.

    Science.gov (United States)

    Zhang, Shicheng; Zheng, Zhijian; Wang, Jinhe; Chen, Jianmin

    2006-12-01

    Lanthanum-doped anatase TiO2 thin films on glass prepared via a sol-gel process have been shown to have much higher photocatalytic activity for the degradation of gaseous benzene than pure anatase TiO2 thin film. The photodecomposition of benzene on both types of TiO2 films follows the first-order kinetics while the CO(2) and CO formation followed the zero-order kinetics. GC/MS identification of the intermediates produced during the photodegradation of benzene revealed that doping lanthanum into TiO2 thin film favors a cleavage of benzene ring. An optimal lanthanum amount with respect to photocatalytic activity was about 2.5 wt% (La2O3/TiO2).

  4. UV-assisted room-temperature chemiresistive NO2 sensor based on TiO2 thin film

    Science.gov (United States)

    Xie, Ting; Sullivan, Nichole; Steffens, Kristen; Wen, Baomei; Liu, Guannan; Debnath, Ratan; Davydov, Albert; Gomez, Romel; Motayed, Abhishek

    2015-01-01

    TiO2 thin film based, chemiresistive sensors for NO2 gas which operate at room temperature under ultraviolet (UV) illumination have been demonstrated in this work. The rf-sputter deposited and post-annealed TiO2 thin films have been characterized by atomic force microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction to obtain surface morphology, chemical state, and crystal structure, respectively. UV-vis absorption spectroscopy and Tauc plots show the optical properties of the TiO2 films. Under UV illumination, the NO2 sensing performance of the TiO2 films shows a reversible change in resistance at room-temperature. The observed change in electrical resistivity can be explained by the modulation of surface-adsorbed oxygen. This work is the first demonstration of a facile TiO2 sensor for NO2 analyte that operates at room-temperature under UV illumination. PMID:26681838

  5. UV-assisted room-temperature chemiresistive NO2 sensor based on TiO2 thin film.

    Science.gov (United States)

    Xie, Ting; Sullivan, Nichole; Steffens, Kristen; Wen, Baomei; Liu, Guannan; Debnath, Ratan; Davydov, Albert; Gomez, Romel; Motayed, Abhishek

    TiO2 thin film based, chemiresistive sensors for NO2 gas which operate at room temperature under ultraviolet (UV) illumination have been demonstrated in this work. The rf-sputter deposited and post-annealed TiO2 thin films have been characterized by atomic force microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction to obtain surface morphology, chemical state, and crystal structure, respectively. UV-vis absorption spectroscopy and Tauc plots show the optical properties of the TiO2 films. Under UV illumination, the NO2 sensing performance of the TiO2 films shows a reversible change in resistance at room-temperature. The observed change in electrical resistivity can be explained by the modulation of surface-adsorbed oxygen. This work is the first demonstration of a facile TiO2 sensor for NO2 analyte that operates at room-temperature under UV illumination.

  6. Spectral and photocatalytic characteristics of TiO2 CVD films on quartz.

    Science.gov (United States)

    Mills, Andrew; Lee, Soo-Keun; Lepre, Anne; Parkin, Ivan P; O'Neill, Shane A

    2002-11-01

    A series of novel CVD films of titanium(IV) oxide of different thicknesses, spanning the range 10-91 nm, are prepared on quartz, via the reaction of titanium(IV) chloride and ethyl acetate, using a CVD technique. The films are clear, mechanically robust and comprise thin layer of nanocrystalline anatase titania of different thicknesses that absorb UV light. The UV-Visible spectral profiles of all the CVD TiO2 films of different thickness are the same and obey Lambert's law (absorbance is porportional to film thickness). A plot of the reciprocal length for the TiO2 coating versus wavelength is reported. The photocatalytic activity of each film to mediate the destruction of a thin layer of stearic acid is investigated. The rate depends directly upon the fraction of light absorbed and the apparent quantum yield for the overall process is 0.00035, which appears low compared with that for sol-gel TiO2 films.

  7. Grain Size and Photocatalytic Activity of Nanometer TiO2 Thin Films Prepared by the Sol-gel Method

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Transparent anatase TiO2 nanometer thin films with photocatalytic activity were prepared via the sol-gel method on soda-lime glass. The thickness, crystalline phase, grain size, surface hydroxyl amount and so on were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and UV-visible spectrophotometer (UV-VIS). The photocatalytic activity of TiO2 thin films was evaluated for the photocatalytic decolorization of aqueous methyl orange. The effects of film thickness on the crystalline phase, grain size, transmittance and photocatalytic activity of nanometer TiO2 thin films were discussed.

  8. Influence of high velocity oxy-fuel parameters on properties of nanostructured TiO2 coatings

    Indian Academy of Sciences (India)

    Maryamossadat Bozorgtabar; Mehdi Salehi; Mohammadreza Rahimipour; Mohammadreza Jafarpour

    2010-12-01

    A liquid fuel high velocity oxy-fuel (HVOF) thermal spray process has been used to deposit TiO2 nanostructured coatings utilizing a commercially available nanopowder as the feedstock. The coatings were characterized by means of X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and transmission electron microscope (TEM), respectively. Photocatalytic activity was evaluated as a rate constant of decomposition reaction of methylene blue (MB) determined from the changes of relative concentration of MB with UV irradiation time. The results indicate that the sprayed TiO2 coatings were composed of both TiO2 phases viz. anatase and rutile, with different phase contents and crystallite sizes. A high anatase content of 80% by volume was achieved at 0.00015, fuel-to-oxygen ratio with nanostructure coating by grain size smaller than feedstock powder. Photocatalytic activity evaluation results indicated that all the TiO2 coatings are effective to degradation MB under UV radiation and their activities differ in different spray conditions. It is found that fuel flow rate strongly influenced on phase transformation of anatase to rutile and by optimizing the rate which can promote structural transformation and grain coarsening in coating and improving photocatalytic activity.

  9. Visible-light photocatalytic properties of Mo-C codoped anatase TiO2 films prepared by magnetron sputtering

    Science.gov (United States)

    Zhe-Peng, Zhang; Biao, Yu; Hai-Bo, Fan; Xin-Liang, Zheng; He-Bao, Yao

    2015-12-01

    A range of different contents of Mo-C codoped TiO2 films were sputtered by using home-made Mo-C codoped TiO2 targets, which were sintered by mixing the Mo2C and TiO2 powder with different mole ratio. We found that the Mo and C ions were successfully incorporated into the lattice of TiO2 films. As a result, the band gap of TiO2 was reduced and the visible-light photocatalytic property was enhanced. The photocatalytic performance of Mo-C codoped TiO2 films was strictly relevant with the band gap and there was a best codoping concentration of 0.01% for the TiO2 film, which processed the smallest band gap and the best photocatalytic property. If the codoping concentration increased, the photocatalytic performance decreased dramatically. Our results suggest that sputtering technique is a convenient method to prepare Mo-C codoped TiO2 films with tunable doping content and high photocatalytic performance.

  10. Morphology and interfacial energetics controls for hierarchical anatase/rutile TiO2 nanostructured array for efficient photoelectrochemical water splitting.

    Science.gov (United States)

    Yang, Jih-Sheng; Liao, Wen-Pin; Wu, Jih-Jen

    2013-08-14

    In this work, a three-dimensional (3D) hierarchical TiO2 nanostructured array is constructed on the basis of the considerations of morphology and interfacial energetics for photoelectrochemical water splitting. The photoelectrode is composed of a core-shell structure where the core portion is a rutile TiO2 nanodendrite (ND) array and the shell portion is rutile and anatase TiO2 nanoparticles (NPs) sequentially located on the surface. The TiO2 ND array provides a fast electron transport pathway due to its quasi-single-crystalline structure. The 3D configuration with NPs in the shell portion provides a larger surface area for more efficient photocharge separation without significantly sacrificing the electron collection efficiency. Moreover, anatase TiO2 NPs constructed on the surface of the ND/rutile TiO2 NP nanostructured array enhance charge separation and suppress charge recombination at the interfacial region due to the higher conduction band edge of anatase TiO2 compared to that of rutile TiO2. A photocurrent density and photoconversion efficiency of 2.08 mA cm(-2) at 1.23 V vs reversible hydrogen electrode (RHE) and 1.13% at 0.51 V vs RHE are, respectively, attained using the hierarchical TiO2 nanostructured array photoelectrochemical cell under illumination of AM 1.5G (100 mW cm(-2)).

  11. Synthesis and characterization of TiO2 and Ag/TiO2 nanostructure

    Science.gov (United States)

    Gahlot, Swati; Thakur, Amit Kumar; Kulshrestha, Vaibhav; Shahi, V. K.

    2013-02-01

    Single phase anatase TiO2 nanoparticles were prepared using Titanium tertachloride (TiCl4) as precursor through an inexpensive method. Well dispersed nanocomposites of silver at TiO2 were synthesized successfully by photochemical route. Both TiO2 and Ag/TiO2 were characterized using X-Ray Diffraction (XRD) and transmission electron microscopy (TEM). The particle size of TiO2 is found to be ˜ 11 nm and ˜ 22 nm for Ag/TiO2, by XRD and confirmed by TEM. TEM micrographs also show the single phase crystal of TiO2 and confirm the deposition of silver among TiO2.

  12. Micro-porous TiO2 thin films grown on surface of Ti substrate

    Institute of Scientific and Technical Information of China (English)

    WU Xiao-hong; QIN Wei; JIANG Zhao-hua; HU Xin-guo; Li Qing-fen

    2004-01-01

    Microporous titanium dioxide thin films have been grown on titanium plates by the micro-plasma oxidation method with different current densities (4, 6, 10 and 14 A/dm2). X-ray diffraction, scanning electronic microscopy and UV-Vis spectrophotometry were used to characterize the films. It is found that the films grown are microporous and consist of crystalline titanium dioxide. The micropore size and the content of anatase and rutile TiO2 phase increase with the applied voltage. The relatively higher degradation efficiency for rhodamine B is obtained in the film produced with a current density of 10 A/dm2.

  13. Multifractal Analysis of Morphology of TiO2 Nano-films

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The SEM and AFM images of three TiO2 nano-films prepared at different conditions were obtained and transformed into digital format.The multifractal analyses for three films were made using height from a depth of thickness of film B and q from 55 to -55.The scale- invariance is very good for all lnχq(ε)~ln( plots and τ(q)~q plots at least close to three orders of magnitude.But the multifractal spectra f(a) of the films are quite distinct due to their different height distribution.

  14. Low-temperature electrodeposition approach leading to robust mesoscopic anatase TiO2 films.

    Science.gov (United States)

    Patra, Snehangshu; Andriamiadamanana, Christian; Tulodziecki, Michal; Davoisne, Carine; Taberna, Pierre-Louis; Sauvage, Frédéric

    2016-02-25

    Anatase TiO2, a wide bandgap semiconductor, likely the most worldwide studied inorganic material for many practical applications, offers unequal characteristics for applications in photocatalysis and sun energy conversion. However, the lack of controllable, cost-effective methods for scalable fabrication of homogeneous thin films of anatase TiO2 at low temperatures (ie. < 100 °C) renders up-to-date deposition processes unsuited to flexible plastic supports or to smart textile fibres, thus limiting these wearable and easy-to-integrate emerging technologies. Here, we present a very versatile template-free method for producing robust mesoporous films of nanocrystalline anatase TiO2 at temperatures of/or below 80 °C. The individual assembly of the mesoscopic particles forming ever-demonstrated high optical quality beads of TiO2 affords, with this simple methodology, efficient light capture and confinement into the photo-anode, which in flexible dye-sensitized solar cell technology translates into a remarkable power conversion efficiency of 7.2% under A.M.1.5G conditions.

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

    Directory of Open Access Journals (Sweden)

    Aytaç GÜLTEKİN

    2014-04-01

    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 films are formed from the nanoparticles and the grain size of the films is changed with Au doping level. Consequently, it is shown that the structural, morphological and optical properties of the TiO2 thin films could be changed by Au nanoparticles-doping. DOI: http://dx.doi.org/10.5755/j01.ms.20.1.3709

  16. Photoactive TiO2 Films Formation by Drain Coating for Endosulfan Degradation

    Directory of Open Access Journals (Sweden)

    Natalia Tapia-Orozco

    2013-01-01

    Full Text Available Heterogeneous photocatalysis is an advanced oxidation process in which a photoactive catalyst, such as TiO2, is attached to a support to produce free radical species known as reactive oxygen species (ROS that can be used to break down toxic organic compounds. In this study, the draining time, annealing temperature, and draining/annealing cycles for TiO2 films grown by the drain coating method were evaluated using a 23 factorial experimental design to determine the photoactivity of the films via endosulfan degradation. The TiO2 films prepared with a large number of draining/annealing cycles at high temperatures enhanced (P>0.05 endosulfan degradation and superoxide radical generation after 30 minutes of illumination with UV light. We demonstrated a negative correlation (R2=0.69; P>0.01 between endosulfan degradation and superoxide radical generation. The endosulfan degradation rates were the highest at 30 minutes with the F6 film. In addition, films prepared using conditions F1, F4, and F8 underwent an adsorption/desorption process. The kinetic reaction constants, Kapp (min−1, were 0.0101, 0.0080, 0.0055, 0.0048, and 0.0035 for F6, F2, F5, F3, and F1, respectively. The endosulfan metabolites alcohol, ether, and lactone were detected and quantified at varying levels in all photocatalytic assays.

  17. Fabrication of TiO2/PU Superhydrophobic Film by Nanoparticle Assisted Cast Micromolding Process.

    Science.gov (United States)

    Li, Jie; Zheng, Jianyong; Zhang, Jing; Feng, Jie

    2016-06-01

    Lotus-like surfaces have attracted great attentions in recent years for their wide applications in water repellency, anti-fog and self-cleaning. This paper introduced a novel process, nanoparticle assisted cast micromolding, to create polymer film with superhydrophobic surface. Briefly, waterborne polyurethane (WPU) sol and nano TiO2/WPU sol were each cast onto the featured surfaces of the poly(dimethylsiloxane) (PDMS) stamps replicated from fresh lotus leaves. After being dried and peeled off from the stamps, PU and TiO2/WPU replica films were created respectively. To the former, only high hydrophobic property was observed with static water contact angle (WCA) at 142.5 degrees. While to the later, superhydrophobic property was obtained with WCA more than 150 degrees and slide angle less than 3 degrees. Scanning electron microscopy (SEM) imaging showed that the PU replica film only had the micro-papillas and the TiO2/PU replica film not only had micro papillas but also had a large number of nano structures distributed on and between the micro-papillas. Such nano and micro hierarchical structures were very similar with those on the natural lotus leaf surface, thus was the main reason for causing superhydrophobic property. Although an elastic PDMS stamp from lotus leaf was used in herein process, hard molds may also be used in theory. This study supplied an alternative technique for large scale production of polymeric films with superhydrophobic.

  18. Optical and morphological properties of ZnO- and TiO2-derived nanostructures synthesized via a microwave-assisted hydrothermal method

    CSIR Research Space (South Africa)

    Moloto, N

    2012-01-01

    Full Text Available A microwave-assisted hydrothermal method was used to synthesize ZnO and TiO2 nanostructures. The experimental results show that the method resulted in crystalline monodispersed ZnO nanorods that have pointed tips with hexagonal crystal phase. TiO2...

  19. Influence of electrical parameters on morphology of nanostructured TiO2 layers developed by electrochemical anodization

    Directory of Open Access Journals (Sweden)

    Strnad Gabriela

    2017-01-01

    Full Text Available Ti6Al4V alloy micro rough surfaces with TiO2 self-organized nanostructured layers were synthesized using electrochemical anodization in phosphate/fluoride electrolyte, at different end potentials (5V, 10V, 15V, and 20 V. The current – time characteristics were recorded, and the link between current evolution and the morphology of developing oxide layers was investigated. On flat surfaces of Ti6Al4V alloy we developed TiO2 layers with different morphologies (random pores, nanopores of 25…50 nm, and highly organized nanotubes of 50…100 nm in diameter depending on electrical parameters of anodization process. In our anodization cell, in optimized conditions, we are able to superimpose nanostructured oxide layers (nanotubular or nanoporous over micro structured surfaces of titanium based materials used for biomedical implants.

  20. A practical demonstration of water disinfection using TiO2 films and sunlight.

    Science.gov (United States)

    Gelover, Silvia; Gómez, Luis A; Reyes, Karina; Teresa Leal, Ma

    2006-10-01

    The scope of this study is the assessment of the efficiency of solar disinfection by heterogeneous photocatalysis with sol-gel immobilized (titanium dioxide) TiO2 films over glass cylinders. The solar disinfection process known as SODIS was considered as a reference. Spring water naturally polluted with coliform bacteria was exposed to sunlight in plastic bottles with and without TiO2 over simple solar collectors and the disinfection effectiveness was measured. Total and fecal coliforms quantification was performed by means of the chromogenic substrate method in order to obtain the efficiency of each disinfection treatment. The disinfection with TiO2 was more efficient than the SODIS process, inactivating total coliforms as well as fecal coliforms. On a sunny day (more than 1000 W m(-2) irradiance), it took the disinfection with immobilized TiO2 15 min of irradiation to inactivate the fecal coliforms to make them undetectable. For inactivation of total coliforms, 30 min was required, so that in less than half the time it takes SODIS, the treated water complies with the microbial standards for drinking water in Mexico. Another important part of this study has been to determine the bacterial regrowth in water after the disinfection processes were tested. After SODIS, bacterial regrowth of coliforms was observed. In contrast, when using the TiO2 catalyst, coliforms regrowth was not detected, neither for total nor for fecal coliforms. The disinfection process using TiO2 kept treated water free of coliforms at least for seven days after sun irradiation. This demonstration opens the possibility of application of this simple method in rural areas of developing countries.

  1. Photocatalytic Activity of Nanostructured Titanium Dioxide Thin Films

    Directory of Open Access Journals (Sweden)

    Zdenek Michalcik

    2012-01-01

    Full Text Available The aim of this paper is to investigate the properties and photocatalytic activity of nanostructured TiO2 layers. The glancing angle deposition method with DC sputtering at low temperature was applied for deposition of the layers with various columnar structures. The thin-film structure and surface morphology were analyzed by XRD, SEM, and AFM analyses. The photocatalytic activity of the films was determined by the rate constant of the decomposition of the Acid Orange 7. In dependence on the glancing angle deposition parameters, three types of columnar structures were obtained. The films feature anatase/rutile and/or amorphous structures depending on the film architecture and deposition method. All the films give the evidence of the photocatalytic activity, even those without proved anatase or rutile structure presence. The impact of columnar boundary in perspective of the photocatalytic activity of nanostructured TiO2 layers was discussed as the possible factor supporting the photocatalytic activity.

  2. Preparation of transparent TiO2 nanocrystalline film for UV sensor

    Institute of Scientific and Technical Information of China (English)

    FU Yao; GAO Wanghe

    2006-01-01

    The nanocrystalline TiO2 film electrodes were prepared by sol-gel method at different calcining temperatures, which had characteristics of different film thickness, uniform transparency, as well as high photoelectric and mechanical stability. Photoelectric measurements show that calcining temperature and film thickness could remarkably influence the photoelectric properties of the electrodes. The film calcined at 450℃ is anatase phase with high crystallinity and strong photoelectric activity, and shows the largest photocurrent. When the temperature is lower than 450℃, the film has weaker crystallinity because of a large number of defects in the film,and this is not favorable for the transport of the photogenerated carriers. And at a temperature higher than 450℃, the photocurrent of the electrode is decreased due to anatase-rutile phase transition in the film. The increase in film thickness is favorable to the enhancement of ultraviolet light (UV) absorption amount, which would improve the photoelectric activity of the film. But, excessive thickness will increase the recombination rate of the electron-hole pairs, and result in a reduction in electrode's photoelectric activity. In addition, the response sensitivity and stability of the photocurrent produced in the electrode are related to bias potential. At a potential of 0.4 V, the electrode shows a saturated photocurrent of 30.8 μA and a response time of ~1 s, suggesting that the prepared TiO2 film electrode can be used for making UV sensors.

  3. Simple way to make Anatase TiO2 films on FTO glass for promising solar cells

    OpenAIRE

    Raghavender, A. T.; Samantilleke, A. P.; Sá,Pedro; Almeida, B. G.; Vasilevskiy, Mikhail; Nguyen Hoa Hong

    2011-01-01

    TiO2 is a wide bandgap semiconductor material used as the photo anode in dye sensitized solar cells (DSSC). The fabrication of TiO2 on conductive glass substrates plays an important role in the solar cell efficiency, since the thickness of the TiO2 coating affects the transmission, photoconductive properties and the efficiency of solar cells. The uncorrected transmission in our fabricated films is as high as 80%, and the bandgap obtained is similar to that of bulk anatase TiO2, co...

  4. Controllable preparation of nanosized TiO2 thin film and relationship between structure of film and its photocatalytic activity

    Institute of Scientific and Technical Information of China (English)

    WEI; Gang; (魏刚); ZHANG; Yuanjing; (张元晶); XIONG; Rongchun; (熊蓉春)

    2003-01-01

    TiO2 nano-crystalline film and fixed bed photocatalytic reactor were prepared by the sol-gel process using tetrabutylorthotitanate as a precursor and glass tube as the substrate. XRD, AFM, SEM and thickness analysis results indicate that the preparation of nano-crystalline film can be controlled by optimizing experiment process. Under the optimized process, the phase of TiO2 in film is anatase, and the grain size is 3-4 nm. The size of particles, which is about 20-80 nm, can be controlled. The thickness of monolayer film is in nanometer grade. The thickness and particles size in films growing on nanometer film can also be controlled in nanometer grade. As a result, the crack of film can be effectively avoided. Rhodamine B degradation results using UV-Vis spectrophotometer show that the activity of nano-crystalline film in the photocatalytic reactor has a good relation with the diameter of TiO2 particles, that is, the film shows high activity when the size is 20-30 nm and greatly reduced when the size is above 60 nm. The activity of film does not decrease with the increase of film thickness, and this result indicates that nano-crystalline film has no ill influence on the transmissivity of ultraviolet light.

  5. Photocathodic Protection of 304 Stainless Steel by Bi2S3/TiO2 Nanotube Films Under Visible Light.

    Science.gov (United States)

    Li, Hong; Wang, Xiutong; Wei, Qinyi; Hou, Baorong

    2017-12-01

    We report the preparation of TiO2 nanotubes coupled with a narrow bandgap semiconductor, i.e., Bi2S3, to improve the photocathodic protection property of TiO2 for metals under visible light. Bi2S3/TiO2 nanotube films were successfully synthesized using the successive ionic layer adsorption and reaction (SILAR) method. The morphology and structure of the composite films were studied by scanning electron microscopy and X-ray diffraction, respectively. UV-visible diffuse reflectance spectra were recorded to analyze the optical absorption property of the composite films. In addition, the influence of Bi2S3 deposition cycles on the photoelectrochemical and photocathodic protection properties of the composite films was also studied. Results revealed that the heterostructure comprised crystalline anatase TiO2 and orthorhombic Bi2S3 and exhibited a high visible light response. The photocurrent density of Bi2S3/TiO2 was significantly higher than that of pure TiO2 under visible light. The sensitization of Bi2S3 enhanced the separation efficiency of the photogenerated charges and photocathodic protection properties of TiO2. The Bi2S3/TiO2 nanotubes prepared by SILAR deposition with 20 cycles exhibited the optimal photogenerated cathodic protection performance on the 304 stainless steel under visible light.

  6. Nanocrystalline TiO2 Composite Films for the Photodegradation of Formaldehyde and Oxytetracycline under Visible Light Irradiation

    Directory of Open Access Journals (Sweden)

    Min Wei

    2017-06-01

    Full Text Available In order to effectively photodegradate organic pollutants, ZnO composite and Co-B codoped TiO2 films were successfully deposited on glass substrates via a modified sol-gel method and a controllable dip-coating technique. Combining with UV–Vis diffuse reflectance spectroscopy (DRS and photoluminescence spectra (PL analyses, the multi-modification could not only extend the optical response of TiO2 to visible light region but also decrease the recombination rate of electron-hole pairs. XRD results revealed that the multi-modified TiO2 film had an anatase-brookite biphase heterostructure. FE-SEM results indicated that the multi-modified TiO2 film without cracks was composed of smaller round-like nanoparticles compared to pure TiO2. BET surface area results showed that the specific surface area of pure TiO2 and the multi-modified TiO2 sample was 47.8 and 115.8 m2/g, respectively. By degradation of formaldehyde and oxytetracycline, experimental results showed that the multi-modified TiO2 film had excellent photodegradation performance under visible light irradiation.

  7. Photocathodic Protection of 304 Stainless Steel by Bi2S3/TiO2 Nanotube Films Under Visible Light

    Science.gov (United States)

    Li, Hong; Wang, Xiutong; Wei, Qinyi; Hou, Baorong

    2017-01-01

    We report the preparation of TiO2 nanotubes coupled with a narrow bandgap semiconductor, i.e., Bi2S3, to improve the photocathodic protection property of TiO2 for metals under visible light. Bi2S3/TiO2 nanotube films were successfully synthesized using the successive ionic layer adsorption and reaction (SILAR) method. The morphology and structure of the composite films were studied by scanning electron microscopy and X-ray diffraction, respectively. UV-visible diffuse reflectance spectra were recorded to analyze the optical absorption property of the composite films. In addition, the influence of Bi2S3 deposition cycles on the photoelectrochemical and photocathodic protection properties of the composite films was also studied. Results revealed that the heterostructure comprised crystalline anatase TiO2 and orthorhombic Bi2S3 and exhibited a high visible light response. The photocurrent density of Bi2S3/TiO2 was significantly higher than that of pure TiO2 under visible light. The sensitization of Bi2S3 enhanced the separation efficiency of the photogenerated charges and photocathodic protection properties of TiO2. The Bi2S3/TiO2 nanotubes prepared by SILAR deposition with 20 cycles exhibited the optimal photogenerated cathodic protection performance on the 304 stainless steel under visible light.

  8. Degradation of Pollutant and Antibacterial Activity of Waterborne Polyurethane/Doped TiO2 Nanoparticle Hybrid Films

    Institute of Scientific and Technical Information of China (English)

    QIU Shan; DENG Fengxia; XU Shanwen; LIU Peng; MIN Xinmin; MA Fang

    2015-01-01

    The waterborne polyurethane/doped TiO2 nanoparticle hybrid films were prepared. Nd, I doped TiO2 was prepared with a 50 nm particle sizefi rstly. The hybridfi lm was prepared by mixing doped TiO2 with waterborne polyurethane, followed by heat treatment. The presence and nanometric distribution of doped TiO2 nanoparticles in prepared membranes is evident according to SEM images. The photocatalytic activities of doped TiO2 were signifi cantly enhanced compared with pure TiO2 powders. After the hybridfi lm fabrication, the photocatalytic activities were almost the same as the pure catalysts withkMB of 0.046. In the antibacterial testing, the hybridfi lms can inhibitE. coli growth. A signifi cant decrease in membranefl uidity and increase of permeability ofE. coli were observed.

  9. TiO2 nanoparticles doped SiO2 films with ordered mesopore channels: a catalytic nanoreactor.

    Science.gov (United States)

    Saha, Jony; Mitra, Anuradha; Dandapat, Anirban; De, Goutam

    2014-04-07

    Titanium dioxide (TiO2) incorporated ordered 2D hexagonal mesoporous silica (SiO2) films on a glass substrate were fabricated for use as a catalytic nanoreactor. Films were prepared using a tetraethyl orthosilicate (TEOS) derived SiO2 sol and a commercially available dispersion of TiO2 nanoparticles (NPs) in the presence of pluronic P123 as the structure directing agent. The effect of TiO2 doping (4-10 mol% with respect to the equivalent SiO2) into the ordered mesoporous SiO2 matrix was thoroughly investigated. The undoped SiO2 film showed a mesostructural transformation after heat-treatment at 350 °C whereas incorporation of TiO2 restricted such a transformation. Among all the TiO2 incorporated films, TEM showed that the 7 equivalent mol% TiO2 doped SiO2 film (ST-7) had an optimal composition which could retain the more organized 2D hexagonal (space group p6mm)-like mesostructures after heat-treatment. The catalytic activities of the TiO2 doped (4-10 mol%) films were investigated for the reduction of toxic KMnO4 in an aqueous medium. ST-7 film showed the maximum catalytic activity, as well as reusability. A TEM study on the resultant solution after KMnO4 reduction revealed the formation of MnO2 nanowires. It was understood that the embedded TiO2 NPs bonded SiO2 matrix increased the surface hydroxyl groups of the composite films resulting in the generation of acidic sites. The catalytic process can be explained by this enhanced surface acidity. The mesoporous channel of the ST-7 films with TiO2 doping can be used as a nanoreactor to form extremely thin MnO2 nanowires.

  10. Thin Functional Films of TiO2 Nanoparticles

    OpenAIRE

    Morozová, Magdalena

    2011-01-01

    Magnetron Sputtering and the Modulated Hollow Cathode Plasma Jet Sputtering. As chemical method the sol-gel process carried out in the templating environment as dip-coating and piezo-jet printing was employed. The produced films differed in many structural characteristics and also in their photoelectrochemical behaviour, as the primary sought function. The produced layers were described by means of atomic force microscopy, scanning electron microscopy, X-ray diffraction, X-ray photoelectron s...

  11. Atomic layer deposition of TiO2 on surface modified nanoporous low-k films.

    Science.gov (United States)

    Levrau, Elisabeth; Devloo-Casier, Kilian; Dendooven, Jolien; Ludwig, Karl F; Verdonck, Patrick; Meersschaut, Johan; Baklanov, Mikhail R; Detavernier, Christophe

    2013-10-01

    This paper explores the effects of different plasma treatments on low dielectric constant (low-k) materials and the consequences for the growth behavior of atomic layer deposition (ALD) on these modified substrates. An O2 and a He/H2 plasma treatment were performed on SiCOH low-k films to modify their chemical surface groups. Transmission FTIR and water contact angle (WCA) analysis showed that the O2 plasma changed the hydrophobic surface completely into a hydrophilic surface, while the He/H2 plasma changed it only partially. In a next step, in situ X-ray fluorescence (XRF), ellipsometric porosimetry (EP), and Rutherford backscattering spectroscopy (RBS) were used to characterize ALD growth of TiO2 on these substrates. The initial growth of TiO2 was found to be inhibited in the original low-k film containing only Si-CH3 surface groups, while immediate growth was observed in the hydrophilic O2 plasma treated film. The latter film was uniformly filled with TiO2 after 8 ALD cycles, while pore filling was delayed to 17 ALD cycles in the hydrophobic film. For the He/H2 plasma treated film, containing both Si-OH and Si-CH3 groups, the in situ XRF data showed that TiO2 could no longer be deposited in the He/H2 plasma treated film after 8 ALD cycles, while EP measurements revealed a remaining porosity. This can be explained by the faster deposition of TiO2 in the hydrophilic top part of the film than in the hydrophobic bulk which leaves the bulk porous, as confirmed by RBS depth profiling. The outcome of this research is not only of interest for the development of advanced interconnects in ULSI technology, but also demonstrates that ALD combined with RBS analysis is a handy approach to analyze the modifications induced by a plasma treatment on a nanoporous thin film.

  12. Crystal Structure And Optical Properties Of TiO2 Thin Films Prepared By Reactive RF Magnetron Sputtering

    Directory of Open Access Journals (Sweden)

    Goto S.

    2015-06-01

    Full Text Available In sputtering deposition process of TiO2, metal Ti or sintered TiO2 target is used as deposition source. In this study, we have compared the characteristic of target materials. When TiO2 target was used, stoichiometric TiO2 films was deposited under the Ar atmosphere containing 1.0% of oxygen. The highest sputtering rate under this atmosphere was 3.9nm/min at 3.4W/cm2. But, sintered TiO2 target is fragile and cannot endure higher density of input power than 3.4W/cm2. On the other hand, Ti target needs higher oxygen concentration (8% in sputtering gas atmosphere for obtaining rutile/anatase. Even though Ti target can be input twice power density of 7.9W/cm2, the highest deposition rate for Ti target was 1.4/nm, which was ~35% of the highest rate for TiO2 target. Then we have study out the composite target consisting of Ti plate and TiO2 chips. Using the composite target, stoichiometric TiO2 films were prepared in the rate of 9.6nm/min at 6.8 W/cm2 under the atmosphere of Ar/2.5%O2. Furthermore, we have found that the TiO2 films obtained from the composite target consisted of about 100% anatase, whereas TiO2 films obtained from other target have rutile dominant structure. The optical band gap energy of the film is determined by using the Tauc plot. The calculated band gap energies for the films deposited by Ti target and composite target were 2.95 and 3.24eV, which are equivalent to that of rutile and anatase structure, respectively.

  13. Detection and characterization of SiO2 and TiO2 nanostructures in dietary supplements.

    Science.gov (United States)

    Lim, Jin-Hee; Sisco, Patrick; Mudalige, Thilak K; Sánchez-Pomales, Germarie; Howard, Paul C; Linder, Sean W

    2015-04-01

    Nanomaterials are beginning to enter our daily lives through various consumer products as the result of technology commercialization. The development of methodologies to detect the presence of nanomaterials in consumer products is an essential element in understanding our exposure. In this study, we have developed methods for the separation and characterization of silicon dioxide (SiO2) and titanium dioxide (TiO2) nanostructures in dietary supplements marketed in products specifically targeted for women. A total of 12 commercial products claiming the inclusion of SiO2 and TiO2, but not making any claims regarding the particle size, were randomly selected for purchase through various retailers. To isolate nanostructures from these products, a simple methodology that combines acid digestion and centrifugation was utilized. Once isolated, the chemical composition, size, morphology, and crystal structure were characterized using mass spectroscopy, light scattering, electron microscopy, and X-ray diffraction techniques. SiO2 and TiO2 nanostructures were detected in 11 of 12 products using these methods. Many of the isolated nanoscale materials showed a high degree of aggregation; however, identified individual structures had at least one dimension below 100 nm. These robust methods can be used for routine monitoring of commercial products for nanoscale oxides of silica and titanium.

  14. Controlled formation of anatase and rutile TiO2 thin films by reactive magnetron sputtering

    Directory of Open Access Journals (Sweden)

    Damon Rafieian

    2015-09-01

    Full Text Available We discuss the formation of TiO2 thin films via DC reactive magnetron sputtering. The oxygen concentration during sputtering proved to be a crucial parameter with respect to the final film structure and properties. The initial deposition provided amorphous films that crystallise upon annealing to anatase or rutile, depending on the initial sputtering conditions. Substoichiometric films (TiOx<2, obtained by sputtering at relatively low oxygen concentration, formed rutile upon annealing in air, whereas stoichiometric films formed anatase. This route therefore presents a formation route for rutile films via lower (<500 °C temperature pathways. The dynamics of the annealing process were followed by in situ ellipsometry, showing the optical properties transformation. The final crystal structures were identified by XRD. The anatase film obtained by this deposition method displayed high carriers mobility as measured by time-resolved microwave conductance. This also confirms the high photocatalytic activity of the anatase films.

  15. Preparation and crystalline phase of a TiO2 porous film by anodic oxidation

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; TAO Jie; ZHANG Weiwei; TAO Haijun; WANG Ling

    2005-01-01

    Anatase titanium dioxide is an active photocatalyst, but it is difficult to immobilize on the substrate. A crystalline TiO2 porous film was prepared directly on the surface of pure titanium by anodic oxidation in this work. Constant voltage and constant current anodic oxidation were adopted with sulphuric acid used as the electrolyte, pure titanium as the anode and copper as the cathode. The morphology and structure of the porous film on the substrate were analyzed with the aid of Field Emission Scanning Electron Microscopy (FESEM) and X-ray Diffraction (XRD). The effects of the parameters of anodic oxidation (such as voltage, the concentration of sulphuric acid, anodization time and current density) on the aperture and the crystalline phase of the TiO2 porous film were systematically investigated. The results indicate that the increase of current density facilitates the augment of the aperture and the generation of anatase and rutile. In addition, the forming mechanism of anatase and rutile TiO2 porous films was discussed.

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

    Science.gov (United States)

    Rafik, Hazem; Mahmoud, Izerrouken; Mohamed, Trari; Abdenacer, Benyagoub

    2014-08-01

    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%.

  17. Photocatalytic and superhydrophilicity properties of N-doped TiO 2 nanothin films

    Science.gov (United States)

    Chekini, M.; Mohammadizadeh, M. R.; Vaez Allaei, S. M.

    2011-06-01

    Pure TiO 2 and nitrogen doped titanium dioxide (N-TiO 2) thin films were prepared by sol-gel method through spin coating on soda lime glass substrates. TiCl 4 and urea were used as Ti and N sources in the sol. XRD results showed nitrogen doping has retarded anatase to rutile phase transformation. The doping also leads to a decrease in roughness of the samples from 4 nm (TiO 2) to 1 nm (N-TiO 2). However, surface analysis by statistical methods reveals that both surfaces have self-affine structure. Optical band gap of thin films was shifted from 3.65 eV (TiO 2) to 3.47 eV (N-TiO 2). Hydrophilic conversion and photocatalytic degradation properties of thin films were investigated and exhibited that N-TiO 2 thin film has more preferable hydrophilicity and photocatalytic properties under UV illumination.

  18. Electrochemically assisted deposition of transparent, mechanically robust TiO2 films for advanced applications

    Science.gov (United States)

    Maino, Giulia; Meroni, Daniela; Pifferi, Valentina; Falciola, Luigi; Soliveri, Guido; Cappelletti, Giuseppe; Ardizzone, Silvia

    2013-11-01

    In recent years, titanium dioxide has received ever growing interest, thanks to its promising applications in numerous fields such as environmental remediation, H2 generation and photovoltaics. Here, transparent and mechanically robust TiO2 films are deposited by a simple and inexpensive electrochemically assisted procedure on various kinds of substrates, both conductive and nonconductive (e.g., glass slides or different metal laminas with variable surface roughness). The obtained films are uniform, crack-free and exhibit excellent chemical, mechanical, and electrochemical robustness. The obtained layers are compared to films prepared by a routine preparation technique, such as dip coating, showing much better morphological, optical, and conductive properties. The photo-activity of TiO2 can be exploited to obtain transparent spectroelectrochemical systems and to control the wetting features of the surface. Applications concerning the modulation of the wettability are presented with respect to both the antifogging and antistain properties. The photoelectrochemical properties of TiO2 films are exploited to activate a photoelectrochemical polymerization of polypyrrole onto an unconductive support. These materials are promising for numerous applications such as smart windows, antifogging mirrors, solar cells, and optically transparent electrodes.

  19. Characterization and Electrical Properties of TiO2 Thin Films Deposited by Pulsed Laser Deposition

    Science.gov (United States)

    Badar, Nurhanna; Kamarulzaman, Norlida

    2011-12-01

    Thin film technology is very important in today's high-tech industry. TiO2 is a high-k dielectric material. Problems with thin film deposition arise when the thickness of the thin layers approaches a few hundred nm to less than 100 nm. High quality thin films within these dimensions are difficult to obtain. Issues of adhesion, crystal mismatch, crystal orientation, surface roughness, densification, etc. are problems that need to be addressed if good quality thin films for devices are to be fabricated. These factors have a relation with the thin film technique used. As an example, spin coating technique may be a cheaper technique but may not result in dense and very smooth surfaces. Pulsed LASER deposition (PLD) is a relatively newer method used in thin film fabrication. The advantages of PLD are, capability of very thin films being deposited on different types of substrates (up to monolayers), control of crystal orientation, capability of depositing materials with complex stoichiometry and ease of methodology with high throughput. This has industrial implications as a good method for thin film preparation. This work involves the deposition of TiO2 thin films using different deposition parameters and chamber environments.

  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. SELF-CLEANING GLASS BASED ON ACID-TREATED TiO2 FILMS WITH PALMITIC ACID AS MODEL POLLUTANT

    Directory of Open Access Journals (Sweden)

    Nurul Hidayat Aprilita

    2010-06-01

    Full Text Available Preparation and characterization of self-cleaning glass based on acid-treated TiO2 films as well as evaluation on their self-cleaning properties have been carried out. Palmitic acid photodegradation was used as model pollutant. Acid-treated TiO2 powders were deposited on glass surface by using spraying technique. The XRD results showed that acid-treated TiO2 film exhibited decreased anatase crystalline size. The corresponding SEM images showed porous surface morphology. Layer densification was observed as the film thickness increased. TiO2 photocatalytic activity increased as the length of UV radiation increased. Best results were obtained at experimental condition of 35 hours UV radiation time. It is also observed that the thickness of TiO2 layers influenced the efficiency of palmitic acid photodegradation. The film with 1.661 µm thick TiO2 layers and 6.933 mg weight (0.7164 mg/cm2 could degrade 97.54 % mg palmitic acid/cm2 thin film.   Keywords: TiO2 films, acid treatment, self-cleaning glass

  2. Low-temperature synthesis and characterization of TiO2 and TiO2-ZrO2 photocatalytically active thin films.

    Science.gov (United States)

    Maver, Ksenija; Stangar, Urska Lavrencic; Cernigoj, Urh; Gross, Silvia; Cerc Korosec, Romana

    2009-05-01

    Transparent TiO(2) and TiO(2)-ZrO(2) (molar ratio Zr/Ti = 0.1) thin films were produced by low-temperature sol-gel processing from nanocrystalline aqueous based solutions. The structural features and compositions of the films treated at room temperature, 100 degrees C and 500 degrees C were investigated by X-ray diffraction, X-ray photoelectron spectroscopy and thermal analysis. Addition of zirconia increased specific surface area (140-230 m(2) g(-1)) and hindered the growth of anatase crystallites, exhibiting a constant size of 6-7 nm in the whole temperature range. These significant changes with respect to pure TiO(2) in anatase crystalline form did not result in significantly and systematically different photocatalytic activity, which was evaluated in terms of aqueous pollutant degradation (azo-dye in water) and self-cleaning ability (fatty contaminant deposit). The films treated at only 100 degrees C showed excellent photocatalytic activity towards azo-dye degradation. Contact angle measurements of aged and contaminated surfaces revealed a fast or sharp hydrophilicity gain under UVA illumination. Accordingly, the results of this study confirmed the potential application of advantageous low-temperature films in water treatment as well as for self-cleaning surfaces.

  3. Temperature influence on microstructure and optical properties of TiO2-Au thin films

    Science.gov (United States)

    Lahmar, A.; Benchaabane, A.; Aderdour, M.; Zeinert, A.; Es-Souni, M.

    2016-02-01

    TiO2-Au thin films were deposited on quartz substrate using sol-gel technique. The influence of the annealing temperature on microstructure and optical properties was examined. SEM micrographs showed a homogeneous distribution of Au nanoparticles when the annealing temperature is increased. X-ray diffraction and Raman spectroscopy allowed the identification of the anatase phase at 500 °C that persisted up to 800 °C. Optical spectra showed the presence of localized plasmon resonance as a result of the presence of Au nanoparticles; the loci of the absorption peaks were found to depend on the annealing temperature. The effective medium model was used to describe the spectrophotometric measurements. Numerical calculations permitted the determination of optical constants. The band gap E g of TiO2-Au thin films was found to decrease from 3.21 to 2.71 eV with increasing annealing temperature.

  4. 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, and each chapter contains details which aim to develop awareness of the subject and the methods used. The content presented here will be useful for graduate students as well as researchers in materials science, physics, chemistry and engineering.

  5. Photoelectrocatalytic Degradation of Sodium Oxalate by TiO2/Ti Thin Film Electrode

    Directory of Open Access Journals (Sweden)

    Chen-Yu Chang

    2012-01-01

    Full Text Available The photocatalytically active TiO2 thin film was deposited on the titanium substrate plate by chemical vapor deposition (CVD method, and the photoelectrocatalytic degradation of sodium oxalate was investigated by TiO2 thin film reactor prepared in this study with additional electric potential at 365 nm irradiation. The batch system was chosen in this experiment, and the controlled parameters were pH, different supporting electrolytes, applied additional potential, and different electrolyte solutions that were examined and discussed. The experimental results revealed that the additional applied potential in photocatalytic reaction could prohibit recombination of electron/hole pairs, but the photoelectrocatalytic effect was decreased when the applied electric potential was over 0.25 V. Among the electrolyte solutions added, sodium sulfate improved the photoelectrocatalytic effect most significantly. At last, the better photoelectrocatalytic degradation of sodium oxalate occurred at pH 3 when comparing the pH influence.

  6. Preparation and photocatalytic activity of composite films containing clustered TiO2 particles and mineral tourmaline powders

    Institute of Scientific and Technical Information of China (English)

    LIANG Jin-sheng; MENG Jun-ping; LIANG Guang-chuan; FENG Yan-wen; DING Yan

    2006-01-01

    The novel composite films containing clustered TiO2 particles and fine tourmaline particles on the surface of copper webs were prepared by the sol-gel method. The microstructures of the composite films were investigated by scanning electron microscopy (SEM),and the photocatalytic activity of the films was evaluated by photocatalytic degradation of methyl orange,respectively. The results indicate that tourmaline particles can obviously influence the microstructures of TiO2 films and enhance the photocatalytic activity due to their spontaneous permanent polarity and high radiotechnology of far infrared. During preparing the composite films,the clustered TiO2 particles with lots of nano-sized ladder layers can grow on the surface of fine tourmaline particles,the thickness of ladder layer is 10 nm,and the average diameter of nano-sized TiO2 particles is 15 nm.

  7. The Influence of Annealing Temperature on the Structure and Properties of TiO2 Films Prepared by Sputtering

    Institute of Scientific and Technical Information of China (English)

    LIU Baoshun; ZHAO Xiujian; ZHAO Qingnan

    2006-01-01

    The TiO2 films were prepared on slides by dc reactive magnetron sputtering, then the samples were annealed at 300 ℃,350 ℃,400 ℃,450 ℃,500 ℃ and 550 ℃,respectively. X-ray diffraction (XRD) was used to obtain the TiO2 film crystalline structure; X-ray photoelectron spectroscopy (XPS) was used to study the film surface stoichiometries; surface morphologies were studied by scanning electron microscopy (SEM); the contact angle was tested to indicate the TiO2 film wettability; and the photocatalytic activity testing was conducted to evaluate the photocatalysis properties. The photocatalytic activity and contact angle testing results were correlated with the crystallinity, surface morphologies and surface *OH concentration of TiO2 films. The samples with a higher polycrystalline anatase structure, rough surface and high *OH concentration displayed a better photoinduced hydrophilicity and a stronger photocatalysis.

  8. Electronic and transport properties of reduced and oxidized nanocrystalline TiO2 films

    Science.gov (United States)

    Rothschild, A.; Komem, Y.; Levakov, A.; Ashkenasy, N.; Shapira, Yoram

    2003-01-01

    Electronic properties of reduced (vacuum-annealed) and oxidized (air-annealed) TiO2 films were investigated by in situ conductivity and current-voltage measurements as a function of the ambient oxygen pressure and temperature, and by ex situ surface photovoltage spectroscopy. The films were quite conductive in the reduced state but their resistance drastically increased upon exposure to air at 350 °C. In addition, the surface potential barrier was found to be much larger for the oxidized versus the reduced films. This behavior may be attributed to the formation of surface and grain boundary barriers due to electron trapping at interface states associated with chemisorbed oxygen species.

  9. Surface photovoltage spectroscopy study of reduced and oxidized nanocrystalline TiO 2 films

    Science.gov (United States)

    Rothschild, A.; Levakov, A.; Shapira, Y.; Ashkenasy, N.; Komem, Y.

    2003-06-01

    Nanocrystalline TiO 2 films used for gas sensors have been studied by means of surface photovoltage spectroscopy and other analytical tools to investigate the oxygen chemisorption effect on the electrical properties of the films. The results show that the surface (and intergranular interface) band bending increases with oxygen exposure due to electron trapping at midgap states induced by chemisorption. The surface electronic structure is revealed by the measurements, allowing determination of the sensing mechanism of these important films. In addition, a photoinduced chemisorption of oxygen at room temperature is observed. This has important implications for low-temperature gas sensors.

  10. One-Dimensional TiO2 Nanostructures as Photoanodes for Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Jie Qu

    2013-01-01

    Full Text Available Titanium dioxide (TiO2 is star materials due to its remarkable optical and electronic properties, resulting in various applications, especially in the fields of dye-sensitized solar cells (DSSCs. Photoanode is the most important part of the DSSCs, which help to adsorb dye molecules and transport the injected electrons. The size, structure, and morphology of TiO2 photoanode have been found to show significant influence on the photovoltaic performance of DSSCs. In this paper, we briefly summarize the synthesis and properties of one-dimensional (1D TiO2 nanomaterials (bare 1D TiO2 nanomaterial and 1D hierarchical TiO2 and their photovoltaic performance in DSSCs.

  11. Tunable Nanostructures and Crystal Structures in Titanium Oxide Films

    Directory of Open Access Journals (Sweden)

    Fuess H

    2008-01-01

    Full Text Available Abstract Controllable nanostructures in spin coated titanium oxide (TiO2 films have been achieved by a very simple means, through change of post deposition annealing temperature. Electron beam imaging and reciprocal space analysis revealed as-deposited TiO2films to be characterized by a dominant anatase phase which converts to the rutile form at 600 °C and reverts to the anatase modification at 1,200 °C. The phase changes are also accompanied by changes in the film microstructure: from regular nanoparticles (as-deposited to nanowires (600 °C and finally to dendrite like shapes at 1,200 °C. Photoluminescence studies, Raman spectral results, and X-ray diffraction data also furnish evidence in support of the observed solid state phase transformations in TiO2.

  12. 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.

  13. Wastewater treatment by sonophotocatalysis using PEG modified TiO2 film in a circular Photocatalytic-Ultrasonic system.

    Science.gov (United States)

    Hu, Xiaohong; Zhu, Qi; Gu, Zhibin; Zhang, Nan; Liu, Na; Stanislaus, Mishma S; Li, Dawei; Yang, Yingnan

    2017-05-01

    TiO2 photocatalyst film recently has been utilized as the potential candidate for the wastewater treatment, due to its high stability and low toxicity. In order to further increase the photocatalytic ability and stability, different molecular weight of polyethylene glycol (PEG) were used to modify TiO2 structure to synthesize porous thin film used in the developed Photocatalytic-Ultrasonic system in this work. The results showed that PEG2000 modified TiO2 calcinated under 450°C for 2h exhibited the highest photocatalytic activity, attributed to the smallest crystallite size and optimal particle size. Over 95.0% of rhodamine B (Rh B) was photocatalytically degraded by optimized PEG2000-TiO2 film after 60min of UV irradiation, while only about 50.8% of Rh B was decolored over pure TiO2 film. Furthermore, optimized PEG2000-TiO2 film was used in a circular Photocatalytic-Ultrasonic system, and the obtained synergy (0.6519) of sonophotocatalysis indicated its extremely high efficiency for Rh B degradation. In this Photocatalytic-Ultrasonic system, larger amount of PEG2000-TiO2 coated glass beads, stronger ultrasonic power and longer experimental time could result to higher degradation efficiency of Rh B. In addition, repetitive experiments showed that about 97.2% of Rh B were still degraded in the fifth experiment by sonophotocatalysis using PEG2000-TiO2 film. Therefore, PEG2000-TiO2 film used in Photocatalytic-Ultrasonic system has promising potential for wastewater treatment, due to its excellent photocatalytic activity and high stability.

  14. Preparation and tribological properties of Sol-Gel TiO2-ZrO2 composite thin films

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    High oriented TiO2-ZrO2 composite thin films on Si (100) and glass sheet were suc-cessfully prepared by sol-gel process followed by dip-coating the ethanol solution of zirconiumoxychloride and titanium tetrachloride. The sol-gel process, microstructure, morphology and tri-bological properties of TiO2 -ZrO2 films were investigated using TGA, DSC, XPS, XRD, AFM anddynamic-static tribometer. The results show that the TiO2-ZrO2films are dense, homogeneous andat a complete tetragonal phase with an excellent antiwear and friction reduction performance. Un-der 0.5N applied load, the friction coefficient is 0.14-0.20 and the antiwear life is more than 5000sliding cycles for both TiO2-ZrO2/ AISI 52100 steel and TiO2-ZrO2/ Si3N4. SEM observation sug-gests that wear mechanism of TiO2 -ZrO2 composite film under low load was fatigue wear, andunder high load was adhesive wear. The TiO2 -ZrO2 films show potential applications as coatingsfor antiwear and friction reduction under the harsh condition.

  15. Methylene blue photocatalytic mineralization under visible irradiation on TiO2 thin films doped with chromium

    Science.gov (United States)

    Diaz-Uribe, Carlos; Vallejo, William; Ramos, Wilkendry

    2014-11-01

    We studied changes in structural, optical and photocatalytic properties of TiO2 thin films due to doping process with chromium. Powders of undoped TiO2 and chromium-doped TiO2 (Cr:TiO2) were synthesized by sol-gel method and, thin films were deposited by doctor blade method. The properties of the thin films were studied by X-ray diffraction (XRD), infrared spectroscopy (IR) and diffuse reflectance. The XRD patterns indicated that doping process changed the crystalline phases radio of TiO2 thin films, furthermore, the optical analysis showed that band gap value of Cr:TiO2 thin films was 31% fewer than undoped TiO2 thin films. Along, Langmuir-Hinshelwood model was used to obtain kinetic information of the photo-mineralization process; results indicated that photocatalytic activity of Cr:TiO2 thin films were four times better than undoped TiO2 thin films; finally the synergic effect was tested by addition of the H2O2, photocatalytic yield was improved from 26% to 61% when methylene blue photo-mineralization was assisted with slightly amount of H2O2.

  16. 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

    2015-03-05

    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.

  17. Photocatalytic Oxidation of Aniline in the Gas Phase Using Porous TiO2 Thin Films

    Institute of Scientific and Technical Information of China (English)

    Fa Wenjun; Li Ying; Gong Chuqing; Zhong Jiacheng

    2006-01-01

    The gas-phase photocatalytic oxidation of aniline on a new kind of porous nano-TiO2 composite films is investigated.The composite film was prepared on glass fiber with the water glass as binders and dilute H2SO4 solution as solidifying reagent.The surface characters were observed by scanning electron microscope.The photocatalytic degradation of aniline on the composite films was carried out in a TiO2AJV system.Some important factors affecting the photodegmdation,such as the concentration of TiO2,the initial concentration of aniline,and the existing water vapor,are also studied.The product ofphotocatalytic oxidation was detected by Fourier transform-Infrared.The partial intermediate products were absorbed on TiO2 surface,which resulted in catalyst deactivation.But when it was irradiated under UV illumination or solar irradiation for some time,the catalyst could be reused without loss of catalytic activity.

  18. Optical and Morphological Properties of ZnO- and TiO2-Derived Nanostructures Synthesized via a Microwave-Assisted Hydrothermal Method

    OpenAIRE

    2012-01-01

    A microwave-assisted hydrothermal method was used to synthesize ZnO and TiO2 nanostructures. The experimental results show that the method resulted in crystalline monodispersed ZnO nanorods that have pointed tips with hexagonal crystal phase. TiO2 nanotubes were also formed with minimum bundles. The mechanism for the formation of the tubes was validated by HRTEM results. The optical properties of both ZnO and TiO2 nanostructures showed characteristics of strong quantum confinement regime. The...

  19. Pt–Ru decorated self-assembled TiO2–carbon hybrid nanostructure for enhanced methanol electrooxidation

    Indian Academy of Sciences (India)

    K G Nishanth; P Sridhar; S Pitchumani; A K Shukla

    2013-06-01

    Porous titanium oxide–carbon hybrid nanostructure (TiO2–C) with a specific surface area of 350 m2/g and an average pore-radius of 21.8 Å is synthesized via supramolecular self-assembly with an in situ crystallization process. Subsequently, TiO2–C supported Pt–Ru electro-catalyst (Pt–Ru/TiO2–C) is obtained and investigated as an anode catalyst for direct methanol fuel cells (DMFCs). X-ray diffraction, Raman spectroscopy and transmission electron microscopy (TEM) have been employed to evaluate the crystalline nature and the structural properties of TiO2–C. TEM images reveal uniform distribution of Pt–Ru nanoparticles (Pt−Ru = 1.5–3.5 nm) on TiO2–C. Methanol oxidation and accelerated durability studies on Pt–Ru/TiO2–C exhibit enhanced catalytic activity and durability compared to carbon-supported Pt–Ru. DMFC employing Pt–Ru/TiO2–C as an anode catalyst delivers a peak-power density of 91 mW/cm2 at 65 °C as compared to the peak-power density of 60 mW/cm2 obtained for the DMFC with carbon-supported Pt–Ru anode catalyst operating under similar conditions.

  20. Stability and Electronic Properties of TiO2 Nanostructures With and Without B and N Doping

    DEFF Research Database (Denmark)

    Mowbray, Duncan; Martinez, Jose Ignacio; García Lastra, Juan Maria

    2009-01-01

    We address one of the main challenges to TiO2 photocatalysis, namely band gap narrowing, by combining nanostructural changes with doping. With this aim we compare TiO2’s electronic properties for small 0D clusters, 1D nanorods and nanotubes, 2D layers, and 3D surface and bulk phases using different...... approximations within density functional theory and GW calculations. In particular, we propose very small (R 5 Å) but surprisingly stable nanotubes with promising properties. The nanotubes are initially formed from TiO2 layers with the PtO2 structure, with the smallest (2,2) nanotube relaxing to a rutile nanorod....... Boron is seen to always give rise to n-type doping while depending on the local bonding geometry, nitrogen may give rise to n-type or p-type doping. For undercoordinated TiO2 surface structures found in clusters, nanorods, nanotubes, layers and surfaces nitrogen gives rise to acceptor states while...

  1. Au nanostructure-decorated TiO2 nanowires exhibiting photoactivity across entire UV-visible region for photoelectrochemical water splitting.

    Science.gov (United States)

    Pu, Ying-Chih; Wang, Gongming; Chang, Kao-Der; Ling, Yichuan; Lin, Yin-Kai; Fitzmorris, Bob C; Liu, Chia-Ming; Lu, Xihong; Tong, Yexiang; Zhang, Jin Z; Hsu, Yung-Jung; Li, Yat

    2013-08-14

    Here we demonstrate that the photoactivity of Au-decorated TiO2 electrodes for photoelectrochemical water oxidation can be effectively enhanced in the entire UV-visible region from 300 to 800 nm by manipulating the shape of the decorated Au nanostructures. The samples were prepared by carefully depositing Au nanoparticles (NPs), Au nanorods (NRs), and a mixture of Au NPs and NRs on the surface of TiO2 nanowire arrays. As compared with bare TiO2, Au NP-decorated TiO2 nanowire electrodes exhibited significantly enhanced photoactivity in both the UV and visible regions. For Au NR-decorated TiO2 electrodes, the photoactivity enhancement was, however, observed in the visible region only, with the largest photocurrent generation achieved at 710 nm. Significantly, TiO2 nanowires deposited with a mixture of Au NPs and NRs showed enhanced photoactivity in the entire UV-visible region. Monochromatic incident photon-to-electron conversion efficiency measurements indicated that excitation of surface plasmon resonance of Au is responsible for the enhanced photoactivity of Au nanostructure-decorated TiO2 nanowires. Photovoltage experiment showed that the enhanced photoactivity of Au NP-decorated TiO2 in the UV region was attributable to the effective surface passivation of Au NPs. Furthermore, 3D finite-difference time domain simulation was performed to investigate the electrical field amplification at the interface between Au nanostructures and TiO2 upon SPR excitation. The results suggested that the enhanced photoactivity of Au NP-decorated TiO2 in the UV region was partially due to the increased optical absorption of TiO2 associated with SPR electrical field amplification. The current study could provide a new paradigm for designing plasmonic metal/semiconductor composite systems to effectively harvest the entire UV-visible light for solar fuel production.

  2. Photocatalytic and optical properties of nanocomposite TiO2-ZnO thin films

    Science.gov (United States)

    Mohamed, S. H.; El-Hagary, M.; Althoyaib, S.

    2012-01-01

    Nanocomposite TiO2-ZnO thin films, with different ZnO content, were deposited by electron-beam evaporation on glass and Si(1 0 0) substrates. The resulting films were annealed in air for 1 h at 450 °C. X-ray diffraction revealed the presence of monoclinic β-TiO2 and hexagonal ZnO for the films prepared with ZnO content of 0 at.% and 100 at.%, respectively. Mixed monoclinic β-TiO2 and hexagonal ZnO phases were observed at higher ZnO content between 50 at.% and 85 at.%. Spectroscopic ellipsometry (SE) was employed to determine the film thickness and optical constants. A two-layer model was used to describe the experimental ellipsometric data. At any wavelength longer than 390 nm, the refractive index decreases gradually with increasing ZnO content in the composite films. The optical band gap increased with increasing ZnO content. The photocatalytic behavior of TiO2-ZnO thin films was mainly evaluated by measuring the decomposition of methylene blue. The nanocomposite film with ZnO content of 8 at.% has the best photocatalytic activities.

  3. Kinetic analysis on photocatalytic degradation of gaseous acetaldehyde, ammonia and hydrogen sulfide on nanosized porous TiO2 films

    Directory of Open Access Journals (Sweden)

    Iis Sopyan

    2007-01-01

    Full Text Available The characteristics of the UV illumination-assisted degradation of gaseous acetaldehyde, hydrogen sulfide, and ammonia on highly active nanostructured-anatase and rutile films were investigated. It was found that the anatase film showed a higher photocatalytic activity than the counterpart did, however, the magnitude of difference in the photocatalytic activity of both films decreased in the order ammonia>acetaldehyde>hydrogen sulfide. To elucidate the reasons for the observation, the adsorption characteristics and the kinetics of photocatalytic degradation of the three reactants on both films were analyzed. The adsorption analysis examined using a simple Langmuir isotherm, showed that adsorbability on both films decreased in the order ammonia>acetaldehyde>hydrogen sulfide, which can be explained in terms of the decreasing electron-donor capacity. Acetaldehyde and ammonia adsorbed more strongly and with higher coverage on anatase film (1.2 and 5.6 molecules/nm2, respectively than on rutile (0.6 and 4.7 molecules/nm2, respectively. Conversely, hydrogen sulfide molecules adsorbed more strongly on rutile film (0.7 molecules/nm2 than on anatase (0.4 molecules/nm2. Exposure to UV light illumination brought about the photocatalytic oxidation of the three gases in contact with both TiO2 films, and the decrease in concentration were measured, and their kinetics are analyzed in terms of the Langmuir–Hinshelwood kinetic model. From the kinetic analysis, it was found that the anatase film showed the photocatalytic activities that were factors of ~8 and ~5 higher than the rutile film for the degradation of gaseous ammonia and acetaldehyde, respectively. However, the activity was only a factor of ~1.5 higher for the photodegradation of hydrogen sulfide. These observations are systematically explained by the charge separation efficiency and the adsorption characteristics of each catalyst as well as by the physical and electrochemical properties of each

  4. Preparation of Ce4+, Sb3+-Codoped TiO2 Films in Electric Field Heating-Treatment

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Titania is an important catalytic material for photo-catalytic applications, and the sol-gel process is one of the most appropriate technologies to prepare TiO2 thin films. In the present paper, the Ce4+, Sb3+-codoped TiO2 films were prepared by sol-gel method, which were heat-treated with an applied electric filed. The phase transformation behavior of Ce4+, Sb3+-codoped TiO2 film in the electric field heating-treatment was studied by XRD and AFM. It is found that the crystals were homogeneous and the average crystal size was about 60 nm. Studies of photo-catalytic degradation show that the photo-catalytic activity of Ce4+, Sb3+-codoped TiO2 films heated to 500 ℃ in an applied electric field was higher.

  5. The Effects of Cu-doped TiO2 Thin Films on Hyperplasia, Inflammation and Bacteria Infection

    Directory of Open Access Journals (Sweden)

    Linhua Li

    2015-11-01

    Full Text Available In the present work, different concentrations of Cu ion (1, 2, 5 and 10 wt % were doped in the TiO2 film by a sol-gel method and dip coating process. The morphology of the Cu-doped TiO2 films were characterized by scanning electron microscopy (SEM and the results showed that the doped Cu made no change to the TiO2 films. The nitric oxide (NO release experiment showed that these Cu-doped surfaces showed the ability of catalytic decomposition of exogenous donor S-nitroso-N-acetyl-penicillamine (SNAP to generate (NO. Based on fluorescence analysis and CCK-8 quantitative results, such films had the ability to inhibit smooth muscle cells adhesion, proliferation and migration with SNAP in vitro. The macrophage adhesion assay and anti-bacterial test proved that such Cu-doped TiO2 films also possessed anti-inflammatory and anti-bacterial abilities. All the abilities above showed positive correlation with the amounts of the doped Cu. This study suggested that the Cu-doped TiO2 films were capable of generating physiological levels of NO in the presence of endogenous donor S-nitrosothiols (RSNO, endowing the TiO2 films with anti-hyperplasia, anti-inflammatory and anti-bacterial abilities.

  6. 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.

  7. Selective responses of human gingival fibroblasts and bacteria on carbon fiber reinforced polyetheretherketone with multilevel nanostructured TiO2.

    Science.gov (United States)

    Wang, Xiao; Lu, Tao; Wen, Jin; Xu, Lianyi; Zeng, Deliang; Wu, Qianju; Cao, Lingyan; Lin, Shuxian; Liu, Xuanyong; Jiang, Xinquan

    2016-03-01

    The long-term success of dental implants relies not only on stable osseointegration but also on the integration of implant surfaces with surrounding soft tissues. In our previous work, titanium plasma immersion ion implantation (PIII) technique was applied to modify the carbon-fiber-reinforced polyetheretherketone (CFRPEEK) surface, constructing a unique multilevel TiO2 nanostructure thus enhancing certain osteogenic properties. However, the interactions between the modified surface and soft-tissue cells are still not clear. Here, we fully investigate the biological behaviors of human gingival fibroblasts (HGFs) and oral pathogens on the structured surface, which determine the early peri-implant soft tissue integration. Scanning electron microscopy (SEM) shows the formation of nanopores with TiO2 nanoparticles embedded on both the sidewall and bottom. In vitro studies including cell adhesion, viability assay, wound healing assay, real-time PCR, western blot and enzyme-linked immunosorbent assay (ELISA) disclose improved adhesion, migration, proliferation, and collagen secretion ability of HGFs on the modified CFRPEEK. Moreover, the structured surface exhibits sustainable antibacterial properties towards Streptococcus mutans, Fusobacterium nucleatum and Porphyromonas gingivalis. Our results reveal that the multilevel TiO2 nanostructures can selectively enhance soft tissue integration and inhibit bacterial reproduction, which will further support and broaden the adoption of CFRPEEK materials in dental fields.

  8. Origin of leakage paths driven by electric fields in Al-doped TiO2 films.

    Science.gov (United States)

    Park, Gyeong-Su; Park, Seong Yong; Heo, Sung; Kwon, Ohseong; Cho, Kyuho; Han, Kwan-Young; Kang, Sung Jin; Yoon, Aram; Kim, Miyoung

    2014-12-23

    The growth of leakage current paths in Al-doped TiO2 (ATO) films is observed by in situ TEM under negative bias stress. Through systematic HAADF-STEM, STEM-EDS, and STEM-EELS studies, it is confirmed that the electric field-induced growth of the Ru-doped TiO2 phase is the main reason for the ATO film's negative leakage.

  9. Silver enhanced TiO2 thin films: photocatalytic characterization using aqueous solutions of tris(hydroxymethyl)aminomethane.

    Science.gov (United States)

    Diesen, Veronica; Dunnill, Charles W; Österberg, Elin; Parkin, Ivan P; Jonsson, Mats

    2014-01-07

    The photocatalytic activity in aqueous solutions of TiO2 and Ag enhanced TiO2 sol-gel produced films was characterized using tris(hydroxymethyl)aminomethane (Tris) under black light (365 nm) and the observed differences in efficiency were further investigated by O2 adsorption studies using the same probe. Hydrogen abstracting species, such as hydroxyl radicals formed upon photocatalysis, are able to abstract hydrogen from Tris. This reaction leads to the formation of formaldehyde which was detected and quantified through a modified version of the Hantzsch reaction. It was found that the Ag enhanced TiO2 film increased the apparent quantum yield from 7% to 12%, partly as a result of a Schottky barrier formation at the metal-semiconductor interface and partly as the sensitizing effect of Ag nanoparticles extends the visible light absorption, which through electron transfer processes enable an efficient charge separation in the TiO2 by attracting acceptor species more efficiently than pure TiO2. The O2 adsorption studies in this paper showed that the Ag enhanced TiO2 film has a stronger adsorption affinity than pure TiO2 towards O2, which make the reduction of O2 more efficient with a subsequent enhanced electron-hole lifetime. It was also found that the Ag enhanced TiO2 film had a poorer adsorption affinity for Tris than the pure TiO2 film, which is a consequence of fewer available surface adsorption sites due to the Ag coverage at 64% which agrees well with the obtained adsorption equilibrium constants (K(LH(TiO2)) = 615 M(-1) and K(LH(Ag-TiO2)) = 320 M(-1)).

  10. Photoeletrochemical Properties of TiO2 Films Modified with Gold Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    徐红; 刘玲; 贾能勤; 杨洁; 严曼明; 江志裕

    2005-01-01

    A nano-Au modified TiO2 electrode was prepared via the oxidation of Ti sheet in flame and subsequent modification with gold nanoparticles. The results of SEM and TEM measurements show that the Au nanoparticles are well dispersed on TiO2 surface. A near 2-fold enhancement in photocurrent was achieved upon the modification with Au nanoparticles. From the results of photocurrent and electrochemical impedance experiments it was found that the flatband potential of nano-Au/TiO2 electrode negatively shifted about 100 mV in 0.5 mol/L Na2SO4 solutions compared with that of bare TiO2 electrode. The improvement of photoelectrochemical performance was explained by the inhibition for charge recombination of photo-induced electrons and holes, and the promotion for interracial charge-transfer kinetics at nano-Au/TiO2 composite film. Such nanometal-semiconductor composite films have the potential application in improving the performance of photoelectrochemical solar cells.

  11. 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.

  12. Nanostructured TiO2-coated activated carbon composite as an electrode material for asymmetric hybrid capacitors.

    Science.gov (United States)

    Kim, Sang-Ok; Lee, Joong Kee

    2012-02-01

    A nanostructured TiO2-coated activated carbon (TAC) composite was synthesized by a modified sol-gel reaction and employed it as a negative electrode active material for an asymmetric hybrid capacitor. The structural characterization showed that the TiO2 nano-layer was deposited on the surface of the activated carbon and the TAC composite has a highly mesoporous structure. The evaluation of electrochemical characteristics of the TAC electrode was carried out by galvanostatic charge/discharge cycling tests and electrochemical impedance spectroscopy. The obtained specific capacitance of the TAC composite was 42.87 F/g, which showed by 27.1% higher than that of the activated carbon (AC). The TAC composite also exhibited an excellent cycle performance and kept 95% of initial capacitance over 500 cycles.

  13. One-Dimensional TiO2 Nanostructures as Photoanodes for Dye-Sensitized Solar Cells

    OpenAIRE

    Jie Qu; Chao Lai

    2013-01-01

    Titanium dioxide (TiO2) is star materials due to its remarkable optical and electronic properties, resulting in various applications, especially in the fields of dye-sensitized solar cells (DSSCs). Photoanode is the most important part of the DSSCs, which help to adsorb dye molecules and transport the injected electrons. The size, structure, and morphology of TiO2 photoanode have been found to show significant influence on the photovoltaic performance of DSSCs. In this paper, we briefly summa...

  14. Influence of heat treatment temperature on bonding and oxidation resistance of diamond particles coated with TiO2 film

    Indian Academy of Sciences (India)

    Xiao-Pan Liu; Dong-Dong Song; Long Wan; Xian-Bing Pang; Zheng Li

    2015-09-01

    In this paper, TiO2 films were coated on the surface of diamond particles using a sol–gel method. The effects of heat treatment temperature on the morphology, composition, chemical bonds, oxidation resistance and compressive strength of diamond particles coated with TiO2 films were characterized through scanning electron microscopy, Fourier transform infrared, Raman spectroscopy, X-ray diffraction analysis, X-ray photoelectron spectroscopy, thermogravimetric–differential scanning calorimetry and compressive strength test. The results showed that when the temperature reached 600°C, the amorphous TiO2 on the diamond particles surface exhibited as a dense anatase film and the Ti–O–C bond formed between TiO2 and the diamond substrates. When temperature reached 800°C, TiO2 films were still in anatase phase and part of the diamond carbon began to graphitize. The graphitizated carbon can also form the Ti–O–C bond with TiO2 film, although TiO2 film would tend to crack in this condition. Meanwhile, the temperature had a serious influence on the oxidation resistance of diamond particles coated with TiO2 films in air. When the heat treatment temperature reached 600°C, the initial oxidation temperature of the coated diamond particles reached the maximum value of 754°C. When the diamond particles were oxidized at 800°C for 0.5 h in air, the weight loss rate reached the minimum value of 6.7 wt% and the compressive strength reached the maximum value of 15.7 N.

  15. Self-cleaning and mechanical properties of modified white cement with nanostructured TiO2.

    Science.gov (United States)

    Khataee, R; Heydari, V; Moradkhannejhad, L; Safarpour, M; Joo, S W

    2013-07-01

    In the present study, self-cleaning and mechanical properties of white Portland cement by addition of commercial available TiO2 nanoparticles with the average particle size of 80 nm were investigated. X-ray diffraction (XRD), transmission electron microscopy (TEM) and BET were used to characterize TiO2 nanoparticles. For determination of self-cleaning properties of TiO2-modified white cement, colorimetric tests in decolorization of C.I. Basic Red 46 (BR46) in comparison to unmodified cement samples was applied. The results indicated that with increasing the amount of TiO2 nanoparticles in modified cement, self-cleaning property of the samples increased. The mechanical properties of TiO2-modified and unmodified cement samples, such as time of setting of hydraulic cement, compressive strength of hydraulic cement mortar and flexural strength of hydraulic cement mortar were examined. The results indicated that addition of TiO2 nanoparticles up to maximum replacement level of 1.0% improved compressive and flexural strength and decreased its setting time.

  16. Simple synthesis and size-dependent surface-enhanced Raman scattering of Ag nanostructures on TiO2 by thermal decomposition of silver nitrate at low temperature.

    Science.gov (United States)

    Wang, Ruey-Chi; Gao, Yong-Siang; Chen, Shu-Jen

    2009-09-16

    A low-temperature dry-process was proposed to synthesize silver nanoparticles, nanorods, and nanoplates on TiO(2) films via thermal decomposition of silver nitrate. X-ray diffraction (XRD) shows only silver crystals were synthesized on the substrate without other byproducts remaining. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) reveal the Ag nanoparticles are single-crystalline face-centered cubic (FCC) structures and their average diameters decrease from 100 to 15 nm with the increase in distance from the source, which corresponds to a decrease of substrate temperature from 350 to 110 degrees C. The Ag nanorods are also single-crystalline FCC structures growing along the [110] direction with diameter and length around 40 and 500 nm, respectively. The morphology of silver nanostructures could be adjusted by varying the working pressure as well as the roughness of the substrates. An obvious size-dependent SERS effect on the TiO(2) substrate with silver nanoparticles was observed for the first time. The enhancement factor increases as the size of the Ag nanoparticles decreases, which is attributed to the increase of hot spots. In addition, fractional brookite in the anatase films could be detected only after being loaded with Ag nanoparticles, which demonstrates the application of SERS in detecting fractional and important features of semiconductors.

  17. Highly Crystalline Nanoparticle Suspensions for Low-Temperature Processing of TiO2 Thin Films.

    Science.gov (United States)

    Watté, Jonathan; Lommens, Petra; Pollefeyt, Glenn; Meire, Mieke; De Buysser, Klaartje; Van Driessche, Isabel

    2016-05-25

    In this work, we present preparation and stabilization methods for highly crystalline TiO2 nanoparticle suspensions for the successful deposition of transparent, photocatalytically active TiO2 thin films toward the degradation of organic pollutants by a low temperature deposition method. A proof-of-concept is provided wherein stable, aqueous TiO2 suspensions are deposited on glass substrates. Even if the processing temperature is lowered to 150-200 °C, the subsequent heat treatment provides transparent and photocatalytically active titania thin layers. Because all precursor solutions are water-based, this method provides an energy-efficient, sustainable, and environmentally friendly synthesis route. The high load in crystalline titania particles obtained after microwave heating opens up the possibility to produce thin coatings by low temperature processing, as a conventional crystallization procedure is in this case superfluous. The impact of the precursor chemistry in Ti(4+)-peroxo solutions, containing imino-diacetic acid as a complexing ligand and different bases to promote complexation was studied as a function of pH, reaction time and temperature. The nanocrystal formation was followed in terms of colloidal stability, crystallinity and particle size. Combined data from Raman and infrared spectroscopy, confirmed that stable titanium precursors could be obtained at pH levels ranging from 2 to 11. A maximum amount of 50.7% crystallinity was achieved, which is one of the highest reported amounts of anatase nanoparticles that are suspendable in stable aqueous titania suspensions. Decoloring of methylene blue solutions by precipitated nanosized powders from the TiO2 suspensions proves their photocatalytic properties toward degradation of organic materials, a key requisite for further processing. This synthesis method proves that the deposition of highly crystalline anatase suspensions is a valid route for the production of photocatalytically active, transparent

  18. Clean TiO2 nanocuboid film tightly attached on a conductive substrate for highly efficient photoelectrochemical water splitting

    Science.gov (United States)

    Meng, Ming; Liu, Kuili; Gan, Zhixing; Zhang, Xiantu; Zhang, Honghui; Sun, Xianke; Zhou, Xiaodong; Chen, Yuanyuan; Feng, Yamin

    2016-12-01

    Anatase TiO2 film consisting of nanocuboids with co-exposed {1 0 1}, {0 0 1} and {1 0 0} facets have been successfully synthesized via thermally annealing amorphous anodized TiO2 nanotube arrays in ambient fluorine. When employed as a photoanode material in photoelectrochemical water splitting, the film of the clean TiO2 nanocuoboids yields a photocurrent density of up to 0.65 mA cm-2 at 0.22 V versus the Ag/AgCl electrode with Faradic efficiency of 100% and exhibits excellent stability, which can be attributed to enhanced photogenerated charge separation and transport to the collecting electrode. This film could also potentially be used for other facet-related applications such as TiO2 based dye-sensitized solar cells, sensors and lithium batteries.

  19. Interferometric sensing platform with dielectric nanostructured thin films.

    Science.gov (United States)

    Celo, D; Post, E; Summers, M; Smy, T; Brett, M J; Albert, J

    2009-04-13

    A new interferometer-based optical sensing platform with nanostructured thin films of ZrO2 or TiO2 as sensing environment has been developed. With the application of an IC compatible Si(3)N(4) waveguide technology, Mach-Zehnder interferometer devices have been fabricated. The application of the glancing angle deposition technique allowed fabrication of nanostructured thin films as the optical sensing environment. Sensing ability of fabricated devices has been demonstrated through the refractive index measurement of a known gas. The transmission spectra and time response measurements have demonstrated a maximum phase shift of Delta phi=pi/10 and a |Delta P(out)|=0.65 dBm. Devices with TiO2 film on the sensing region performed much better than devices with ZrO2, with sensitivity twice as high.

  20. Low-temperature preparation of rutile-type TiO2 thin films for optical coatings by aluminum doping

    Science.gov (United States)

    Ishii, Akihiro; Kobayashi, Kosei; Oikawa, Itaru; Kamegawa, Atsunori; Imura, Masaaki; Kanai, Toshimasa; Takamura, Hitoshi

    2017-08-01

    A rutile-type TiO2 thin film with a high refractive index (n), a low extinction coefficient (k) and small surface roughness (Ra) is required for use in a variety of optical coatings to improve the controllability of the reflection spectrum. In this study, Al-doped TiO2 thin films were prepared by pulsed laser deposition, and the effects of Al doping on their phases, optical properties, surface roughness and nanoscale microstructure, including Al distribution, were investigated. By doping 5 and 10 mol%Al, rutile-type TiO2 was successfully prepared under a PO2 of 0.5 Pa at 350-600 °C. The nanoscale phase separation in the Al-doped TiO2 thin films plays an important role in the formation of the rutile phase. The 10 mol%Al-doped rutile-type TiO2 thin film deposited at 350 °C showed excellent optical properties of n ≈ 3.05, k ≈ 0.01 (at λ = 400 nm) and negligible surface roughness, at Ra ≈ 0.8 nm. The advantages of the superior optical properties and small surface roughness of the 10 mol%Al-doped TiO2 thin film were confirmed by fabricating a ten-layered dielectric mirror.

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

    Science.gov (United States)

    Wang, Sheng-Hung; Wang, Kuo-Hua; Dai, Yong-Ming; Jehng, Jih-Mirn

    2013-01-01

    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&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 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.

  2. A non-labeled DNA biosensor based on light addressable potentiometric sensor modified with TiO_2 thin film

    Institute of Scientific and Technical Information of China (English)

    Xiao-lin ZONG; Chun-sheng WU; Xiao-ling WU; Yun-feng LU; Ping WANG

    2009-01-01

    Titanium dioxide (TiO_2) thin film was deposited on the surface of the light addressable potentiometric sensor (LAPS) to modify the sensor surface for the non-labeled detection of DNA molecules. To evaluate the effect of ultraviolet (UV) treatment on the silanization level of TiO_2 thin film by 3-aminopropyltrietboxysilane (APTS), fluorescein isothiocyanate (FITC) was used to label the amine group on the end of APTS immobilized onto the TiO_2 thin film. We found that, with UV irradiation, the silani-zation level of the irradiated area of the TiO_2 film was improved compared with the non-irradiated area under well-controlled conditions. This result indicates that TiO_2 can act as a coating material on the biosensor surface to improve the effect and effi-ciency of the covalent immobilization of biomolecules on the sensor surface. The artificially synthesized probe DNA molecules were covalently linked onto the surface of TiO_2 film. The hybridization of probe DNA and target DNA was monitored by the recording of Ⅰ-Ⅴ curves that shift along the voltage axis during the process of reaction. A significant LAPS signal can be detected at 10 μmol/L of target DNA sample.

  3. Characterization of Nanostructured Polymer Films

    Science.gov (United States)

    2014-12-23

    AFRL-OSR-VA-TR-2015-0059 Characterization of Nanostructured Polymer Films RODNEY PRIESTLEY TRUSTEES OF PRINCETON UNIVERSITY Final Report 12/23/2014...Report 3. DATES COVERED (From - To) 06/01/2012-08/31/2014 4. TITLE AND SUBTITLE Characterization of Nanostructured Polymer Films 5a. CONTRACT...properties is due to the film morphology, i.e., the films are nanostructured . The aim of this proposal was to understand the mechanism of film formation and

  4. Mesostructured perovskite solar cells based on highly ordered TiO2 network scaffold via anodization of Ti thin film

    Science.gov (United States)

    Huang, Aibin; Zhu, Jingting; Zheng, Jianyun; Yu, Yu; Liu, Yan; Yang, Songwang; Bao, Shanhu; Lei, Lei; Jin, Ping

    2017-02-01

    An anodized TiO2 interconnected network was fabricated and utilized as a mesoporous scaffold and electron transporter in perovskite solar cells. By modifying the synthesis parameters, the morphological features of the interconnected TiO2 nanostructures can be widely tuned and precisely controlled. The functional properties of the anodized TiO2 network are found to be severely influenced by morphology as well as the extent of oxidation. The device with the optimized TiO2 network exhibits superior electron extraction and transferability, resulting in conspicuous enhancement of the photocurrent and power conversion efficiency (PCE). This work proposes a promising and facile method for improving the performance of perovskite solar cells.

  5. Mesostructured perovskite solar cells based on highly ordered TiO2 network scaffold via anodization of Ti thin film.

    Science.gov (United States)

    Huang, Aibin; Zhu, Jingting; Zheng, Jianyun; Yu, Yu; Liu, Yan; Yang, Songwang; Bao, Shanhu; Lei, Lei; Jin, Ping

    2017-02-03

    An anodized TiO2 interconnected network was fabricated and utilized as a mesoporous scaffold and electron transporter in perovskite solar cells. By modifying the synthesis parameters, the morphological features of the interconnected TiO2 nanostructures can be widely tuned and precisely controlled. The functional properties of the anodized TiO2 network are found to be severely influenced by morphology as well as the extent of oxidation. The device with the optimized TiO2 network exhibits superior electron extraction and transferability, resulting in conspicuous enhancement of the photocurrent and power conversion efficiency (PCE). This work proposes a promising and facile method for improving the performance of perovskite solar cells.

  6. Preparation and characterization of compact TiO2 film used in Gr(a)tzel solar cells

    Institute of Scientific and Technical Information of China (English)

    LI Bin; WANG Liduo; ZHANG Deqiang; QIU Yong

    2004-01-01

    We report for the first time the preparation method of compact TiO2 film using titanium butoxide-petroleum ether solution, by means of dipping and sintering. Our estimation of the component of this thin film was confirmed by XPS test. Studies of AFM showed the influence of preparation condition upon surface morphology. The transmitted spectrum of this compact TiO2 film was also investigated, which presented an excellent transmittance of this film in the visible light region. We arrive at a conclusion, according to the I-V characteristics of solid-state Gratzel solar cells utilizing this kind of compact film, that this compact TiO2 film functions well in secluding the conducting substrate from the hole-conducting material.

  7. Fabrication of Fiber Bragg Grating Coating with TiO2 Nanostructured Metal Oxide for Refractive Index Sensor

    Directory of Open Access Journals (Sweden)

    Shaymaa Riyadh Tahhan

    2017-01-01

    Full Text Available To increase the sensitivity of biosensor a new approach using an optical fiber Bragg grating (FBG coated with a suitable nanostructured metal oxide (NMO is proposed which is costly effective compared to other biosensors. Bragg grating was written on a D-shaped optical fiber by phase mask method using a 248 nm KrF excimer laser for a 5 min exposure time producing a grating with a period of 528 nm. Titanium dioxide (TiO2 nanostructured metal oxide was coated over the fiber for the purpose of increasing its sensing area. The etched D-shaped FBG was then coated with 312 nm thick TiO2 nanostructured layer to ensure propagating the radiation modes within the core. The final structure was used to sense deionized water and saline. The etched D-shaped FBG original sensitivity before coating to air-deionized water and to air-saline was 0.314 nm/riu and 0.142 nm/riu, respectively. After coating the sensitivity became 1.257 nm/riu for air-deionized water and 0.857 nm/riu for air-saline.

  8. Superhydrophilic porous TiO 2 film prepared by phase separation through two stabilizers

    Science.gov (United States)

    Huang, Weixin; Deng, Wei; Lei, Ming; Huang, Hong

    2011-03-01

    A novel method was developed to produce a TiO 2 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 TiO 2 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.

  9. Fabrication of TiO2 Nanotube Thin Films and Their Gas Sensing Properties

    Directory of Open Access Journals (Sweden)

    Yongxiang Li

    2009-01-01

    Full Text Available The fabrication process and the growth mechanism of titanium/titania nanotubes prepared by anodization process is reviewed, and their applications in the fields of dye sensitized solar cells, photocatalysts, electrochromic devices, gas sensors, and biomaterials are presented. The anodization of Ti thin films on different substrates and the growth process of anodic titanium oxide are described using the current-time curves. Special attention is paid on the influences of the initial film smoothness on the resulted nanoporous morphologies. The “threshold barrier layer thickness model” is used to discuss the growth mechanism. As a case study for gas sensing, anodized highly ordered TiO2 nanotube arrays and nanoporous thin films that show porous surface with an average diameter of 25 nm and interpore distance of 40 nm were prepared. Gas sensors based on such nanotube arrays and nanoporous thin films were fabricated, and their sensing properties were investigated. Excellent H2 gas sensing properties were obtained for sensors prepared from these highly ordered TiO2 nanotube arrays, which present stable response even at a low operating temperature of 90°C. Based on our experimental results, “H-induced O2− desorption” mechanism was used for explaining the hydrogen gas sensing mechanism.

  10. Light scattering of nanocrystalline TiO2 film used in dye-sensitized solar cells

    Institute of Scientific and Technical Information of China (English)

    Xiong Bi-Tao; Zhou Bao-Xue; Bai Jing; Zheng Qing; Liu Yan-Biao; Cai Wei-Min; Cai Jun

    2008-01-01

    This paper studies the light scattering and adsorption of nanocrystalline TiO2 porous films used in dye-sensitized solar cells composed of anatase and/or rutile particles by using an optical four-flux radiative transfer model.These light properties are difficult to measure directly on the functioning solar cells and they can not be calculated easily from the first-principle computational or quantitative theoretical evaluations.These simulation results indicate that the light scattering of 1-25 nm TiO2 panicles is negligible,but it is effective in the range of 80 and 180 nm.A suitable mixture of small particles(10 nm radius),which are resulted in a large effective surface,and of larger particles(150 nm radius),which are effective light scatterers,have the potential to enhance solar absorption significantly.The rutile crystals have a larger refractive index and thus the light harvest of the mixtures of such larger rutile and relatively small anatase particles is improved in comparison with that of pure anatase films.The light absorption of the 10μm double-layered films is also examined.A maximal light absorption of double-layered film is gotten when the thickness of the first layer of 10 nm-sized anatase particles is comparable to that of the second larger rutile layer.

  11. 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.

  12. Photocatalytic Oxidation of NOx with Porous TiO2 Nanometer Thin Film

    Institute of Scientific and Technical Information of China (English)

    WANG Song-lin; TIAN Li-hong; ZHONG Jia-cheng; ZAN Ling

    2005-01-01

    A new kind of porous nano-TiO2 composite films was prepared on the glass substrate with the water glass as binders and the sodium fluorosilicate as solidifying reagent.The morphologies of the films were studied by scanning dectron microscope(SEM). The UV-Vis spectrophotometer was also used to investigate the absorption of the films. The gasphase photocatalytic oxidation of nitrogen oxides on the composite film was carried out in TiO2/UV system, and some important factors affecting the photocatalytic oxidation were also studied such as the catalyst concentration, vapor pressure and the presence of oxygen. The results showed the conversion of NOx reached 97. 5% after 2 h UV-irradiation. The final product of photo-oxidation was detected to be HNO3 by FTIR. The way of photocatalytic oxidation of NOx was possibly useful in the practical application.

  13. High Pressure Raman Spectroscopy Of TiO2 Thin Films

    Science.gov (United States)

    Hess, Nancy J.; Exarhos, Gregory J.

    1989-07-01

    The pressure dependences of the Raman active modes in submicrometer films of the anatase and rutile crystalline phases of TiO2 have been determined at pressures approaching 90 Kbar. Films investigated have been prepared by reactive sputter deposition and sol-gel techniques. Band frequency shifts as a function of applied pressure for the rutile phase are in agreement with measurements from single crystal samples. However, sol-gel films (anatase) exhibit larger frequency shifts than powder or single crystal samples, and do not undergo the expected pressure-induced phase transformation to the Ti02-II phase. This anomalous pressure response is discussed in terms of the complex film microstructure evaluated from TEM cross-sectional measurements.

  14. 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.

  15. Fe doped TiO2-graphene nanostructures: synthesis, DFT modeling and photocatalysis

    Science.gov (United States)

    Farhangi, Nasrin; Ayissi, Serge; Charpentier, Paul A.

    2014-08-01

    In this work, Fe-doped TiO2 nanoparticles ranging from a 0.2 to 1 weight % were grown from the surface of graphene sheet templates containing -COOH functionalities using sol-gel chemistry in a green solvent, a mixture of water/ethanol. The assemblies were characterized by a variety of analytical techniques, with the coordination mechanism examined theoretically using the density functional theory (DFT). Scanning electron microscopy and transmission electron microscopy images showed excellent decoration of the Fe-doped TiO2 nanoparticles on the surface of the graphene sheets >5 nm in diameter. The surface area and optical properties of the Fe-doped photocatalysts were measured by BET, UV and PL spectrometry and compared to non-graphene and pure TiO2 analogs, showing a plateau at 0.6% Fe. Interactions between graphene and Fe-doped anatase TiO2 were also studied theoretically using the Vienna ab initio Simulation Package based on DFT. Our first-principles theoretical investigations validated the experimental findings, showing the strength in the physical and chemical adsorption between the graphene and Fe-doped TiO2. The resulting assemblies were tested for photodegradation under visible light using 17β-estradiol (E2) as a model compound, with all investigated catalysts showing significant enhancements in photocatalytic activity in the degradation of E2.

  16. Synthesis and nanostructural investigation of TiO2 nanorods doped by SiO2

    Indian Academy of Sciences (India)

    M Riazian; A Bahari

    2012-02-01

    TiO2 Nano rods can be used as dye-sensitized solar cells, various sensors and photocatalysts. These nanorods are synthesized by a hydrothermal corrosion process in NaOH solution at 200°C using TiO2 powder as the source material. In the present work, the synthesis of TiO2 nanorods in anatase, rutile and Ti7O13 phases and synthesis of TiO2 nanorods by incorporating SiO2 dopant, using the sol–gel method and alkaline corrosion are reported. The morphologies and crystal structures of the TiO2 nanorods are characterized using field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM) and X-ray diffraction (XRD) study. The obtained results show not only an aggregation structure at high calcination temperatures with spherical particles but also Ti–O–Si bonds having four-fold coordination with oxygen in SiO4-.

  17. Preparation of Highly Crystalline TiO2 Nanostructures by Acid-assisted Hydrothermal Treatment of Hexagonal-structured Nanocrystalline Titania/Cetyltrimethyammonium Bromide Nanoskeleton

    Directory of Open Access Journals (Sweden)

    Sakai Hideki

    2010-01-01

    Full Text Available Abstract Highly crystalline TiO2 nanostructures were prepared through a facile inorganic acid-assisted hydrothermal treatment of hexagonal-structured assemblies of nanocrystalline titiania templated by cetyltrimethylammonium bromide (Hex-ncTiO2/CTAB Nanoskeleton as starting materials. All samples were characterized by X-ray diffraction (XRD and transmission electron microscopy (TEM. The influence of hydrochloric acid concentration on the morphology, crystalline and the formation of the nanostructures were investigated. We found that the morphology and crystalline phase strongly depended on the hydrochloric acid concentrations. More importantly, crystalline phase was closely related to the morphology of TiO2 nanostructure. Nanoparticles were polycrystalline anatase phase, and aligned nanorods were single crystalline rutile phase. Possible formation mechanisms of TiO2 nanostructures with various crystalline phases and morphologies were proposed.

  18. Preparation of K-doped TiO2 nanostructures by wet corrosion and their sunlight-driven photocatalytic performance

    Science.gov (United States)

    Shin, Eunhye; Jin, Saera; Kim, Jiyoon; Chang, Sung-Jin; Jun, Byung-Hyuk; Park, Kwang-Won; Hong, Jongin

    2016-08-01

    K-doped TiO2 nanowire networks were prepared by the corrosion reaction of Ti nanoparticles in an alkaline (potassium hydroxide: KOH) solution. The prepared nanostructures were characterized by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) analysis, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, X-ray diffraction (XRD) and photoluminescence (PL) spectra. Their sunlight-driven photocatalytic activity was also investigated with differently charged dye molecules, such as methylene blue, rhodamine B and methyl orange. The adsorption of the dye molecules on the photocatalyst surface would play a critical role in their selective photodegradation under sunlight illumination.

  19. Surface Hydrophilicity and Antifungal Properties of TiO2 Films Coated on a Co-Cr Substrate.

    Science.gov (United States)

    Huang, Lijuan; Jing, Shuanglin; Zhuo, Ou; Meng, Xiangfeng; Wang, Xizhang

    2017-01-01

    The purpose of this study was to deposit a thin layer of TiO2 on a Co-Cr substrate, serving as a deactivation film protecting the metallic fitting surface. The crystalline structure and surface morphology of the film were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). A scratch tester was used to examine the adhesion strength between the TiO2 film and the Co-Cr substrate. The water contact angles and antifungal efficacy against C. albicans of the TiO2-deposited Co-Cr samples were investigated and further compared with those of uncoated Co-Cr substrates. The results indicated that a pure anatase microstructure and dense and smooth surface texture as well as strong binding to the underlying metallic surface were obtained. The originally hydrophobic Co-Cr alloy surface turned hydrophilic after TiO2 film coating. Most importantly, the TiO2-coated surface showed a superior antifungal capability under UV-irradiation compared to those without TiO2 coating. This work contains meaningful results for the development of a new metallic framework coating with improved hydrophilicity and antifungal properties.

  20. Surface Hydrophilicity and Antifungal Properties of TiO2 Films Coated on a Co-Cr Substrate

    Directory of Open Access Journals (Sweden)

    Lijuan Huang

    2017-01-01

    Full Text Available The purpose of this study was to deposit a thin layer of TiO2 on a Co-Cr substrate, serving as a deactivation film protecting the metallic fitting surface. The crystalline structure and surface morphology of the film were characterized by X-ray diffraction (XRD and scanning electron microscopy (SEM. A scratch tester was used to examine the adhesion strength between the TiO2 film and the Co-Cr substrate. The water contact angles and antifungal efficacy against C. albicans of the TiO2-deposited Co-Cr samples were investigated and further compared with those of uncoated Co-Cr substrates. The results indicated that a pure anatase microstructure and dense and smooth surface texture as well as strong binding to the underlying metallic surface were obtained. The originally hydrophobic Co-Cr alloy surface turned hydrophilic after TiO2 film coating. Most importantly, the TiO2-coated surface showed a superior antifungal capability under UV-irradiation compared to those without TiO2 coating. This work contains meaningful results for the development of a new metallic framework coating with improved hydrophilicity and antifungal properties.

  1. Influence of temperature on the photodegradation process using Ag-doped TiO2nanostructures: Negative impact with the nanofibers

    DEFF Research Database (Denmark)

    Barakata, Nasser A.M.; Kanjwal, Muzafar Ahmad; Chronakis, Ioannis S.

    In this study, the influence of the temperature on the photodegradation process using Ag-doped TiO2 nanostructures was investigated. Two morphologies were used; nanoparticles and nanofibers. The nanofibers were synthesized by electrospinning of a sol–gel consisting of titanium isopropoxide, silver......, increasing the temperature has positive impact as the best degradation was obtained at 55 °C. In contrast to the known influence of the temperature on the chemical reactions, in case of the nanofibrous morphology, the temperature has negative impact as the experimental work indicated that the optimum...... the molecules escape from the active thin film surrounding the photocatalyst. Overall, this study shows that the nanofibrous morphology strongly enhances the surface activity of the photocatalyst which generates negative influence of the temperature....

  2. Nanostructured 2D Diporphyrin Honeycomb Film: Photoelectrochemistry, Photodegradation, and Antibacterial Activity.

    Science.gov (United States)

    Zhao, Yuewu; Shang, Qiuwei; Yu, Jiachao; Zhang, Yuanjian; Liu, Songqin

    2015-06-10

    Surface patterns of well-defined nanostructures play important roles in fabrication of optoelectronic devices and applications in catalysis and biology. In this paper, the diporphyrin honeycomb film, composed of titanium dioxide, protoporphyrin IX, and hemin (TiO2/PPIX/Hem), was synthesized using a dewetting technique with the well-defined polystyrene (PS) monolayer as a template. The TiO2/PPIX/Hem honeycomb film exhibited a higher photoelectrochemical response than that of TiO2 or TiO2/PPIX, which implied a high photoelectric conversion efficiency and a synergistic effect between the two kinds of porphyrins. The TiO2/PPIX/Hem honeycomb film was also a good photosensitizer due to its ability to generate singlet oxygen ((1)O2) under irradiation by visible light. This led to the use of diporphyrin TiO2/PPIX/Hem honeycomb film for the photocatalytic inactivation of bacteria. In addition, the photocatalytic activities of other metal-diporphyrin-based honeycomb films, such as TiO2/MnPPIX/Hem, TiO2/CoPPIX/Hem, TiO2/NiPPIX/Hem, TiO2/CuPPIX/Hem, and TiO2/ZnPPIX/Hem, were investigated. The result demonstrated that the photoelectric properties of diporphyrin-based film could be effectively enhanced by further coupling of porphyrin with metal ions. Such enhanced performance of diporphyrin compounds opened a new way for potential applications in various photoelectrochemical devices and medical fields.

  3. Effects of Ni doping on photocatalytic activity of TiO2 thin films prepared by liquid phase deposition technique

    Indian Academy of Sciences (India)

    Noor Shahina Begum; H M Farveez Ahmed; K R Gunashekar

    2008-10-01

    The TiO2 thin films doped by Ni uniformly and non-uniformly were prepared on glass substrate from an aqueous solution of ammonium hexa-fluoro titanate and NiF2 by liquid phase deposition technique. The addition of boric acid as an – scavenger will shift the equilibrium to one side and thereby deposition of the film is progressed. The rate of the reaction and the nature of deposition depend on growing time and temperature. The resultant films were characterized by XRD, EDAX, UV and SEM. The result shows that the deposited films have amorphous background, which becomes crystalline at 500°C. The EDAX data confirms the existence of Ni atoms in TiO2 matrix. XRD analysis reveals the peaks corresponding to Ni but no peak of crystalline NiO was found. The transmittance spectra of Ni uniformly and non-uniformly doped TiO2 thin films show `blue shift and red shift’, respectively. Ni-doped TiO2 thin films can be used as photocatalyst for the photodegradation of methyl orange dye. It was found that, organic dye undergoes degradation efficiently in presence of non-uniformly Ni-doped TiO2 thin films when compared to uniformly doped films and pure TiO2 films under visible light. The photocatalytic activity increases with increase in the concentration of Ni in case of nonuniformly doped thin films but decreases with the concentration when uniformly doped thin films were used.

  4. Preparation of TiO2 nanometer thin films with high photocatalytic activity by reverse micellar method

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Two kinds of TiO2 nanometer thin films were prepared on stainless steel by the reverse micellar and sol-gelmethods, respectively. The calcined TiO2 thin films were characterized by X-ray diffraction (XRD), atomic force micros-copy (AFM), BET surface area and X-ray photoelectron spectroscopy (XPS). Photocatalytic activity was evaluated byphotocatalytic decoloration of methyl orange aqueous solution. The results showed that the TiO2 thin films prepared by re-verse micellar method (designated as RM-TiO2 films) showed higher photocatalytic activity than those by sol-gel method(designated as SG-TiO2 films). This is attributed to the fact that the former is composed of smaller monodispersed sphericalparticles with a size of about 15 nm and possesses higher surface areas.

  5. The Photocatalytic Property of Nitrogen-Doped TiO2 Nanoball Film

    Directory of Open Access Journals (Sweden)

    Haiying Wang

    2013-01-01

    Full Text Available TiO2 nanoball films of nitrogen doping and no doping were prepared by anodic oxidation method. The nitrogen-doped samples exhibited significant enhanced absorption in visible light range, narrowing band gap from 3.2 eV to 2.8 eV and the smaller nanoball diameter size. The concentrations of methyl blue reduce to nearly 44% after 4-hour photodecomposition test by nitrogen-doped sample. It is indicated that there may be two main reasons for the enhanced photocatalytic activity: the increase of O vacancy and photocatalytic reactivity surface area in nitrogen-doped samples.

  6. Unsymmetrical extended -conjugated zinc phthalocyanine for sensitization of nanocrystalline TiO2 films

    Indian Academy of Sciences (India)

    L Giribabu; Ch Vijay Kumar; P Yella Reddy; Jun-Ho Yum; M Grätzel; Md K Nazeeruddin

    2009-01-01

    We have designed and synthesized a new unsymmetrical zinc phthalocyanine based on `push-pull’ and extended -conjugation concept, PCH008. The new sensitizer was fully characterized by CHN anlysis, UV-Vis., fluorescence spectroscopies and cyclic voltammetry. The new sensitizer which upon anchoring onto nanocrystalline TiO2 film exhibit a short circuit current of 5.63 mA cm-2, open circuit potential of 557.0 mV and a fill factor of 0.75 corresponding to an overall conversion efficiency of 2.35% under standard global air mass (AM) 1.5 solar conditions and compared its performance with literature reported phthalocyanine dyes.

  7. Photocatalytic degradation kinetics of Rhodamine B cata-lyzed by nanosized TiO2 film

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A fixed bed photocatalytic reactor was designed, and dynamic fast scan of UV-Vis adsorption spectrum was adopted to study the photocatalytic degradation dynamic behavior of Rhodamine B, a kind of dye generally recognized as to be degraded difficultly, on the surface of nanosized TiO2 thin film. The results indicate that the photocatalytic degradation process of Rhodamine B does not comply with the first-order reaction kinetic process. As a result, a kinetic model of Rhodamine B photocatalytic degradation reaction is brought forward, and the model is proved by the theoretical deduction and experiment.

  8. Hybrid Solar Cell with TiO2 Film: BBOT Polymer and Copper Phthalocyanine as Sensitizer

    Directory of Open Access Journals (Sweden)

    Saptadip Saha

    2016-01-01

    Full Text Available An organic-inorganic hybrid solar cell was fabricated using Titanium dioxide (TiO2: 2,5-bis(5-tert-butyl-2-benzoxazolyl thiophene (BBOT film and Copper Phthalocyanine (CuPc as a sensitizer. BBOT was used in photodetector in other reported research works, but as per best of our knowledge, it was not implemented in solar cells till date. The blend of TiO2: BBOT blend was used to fabricate the film on ITO-coated glass and further a thin layer of CuPc was coated on the film. This was acted as photoanode and another ITO coated glass with a platinum coating was used as a counter electrode (cathode. An optimal blend of acetonitrile (solvent (50-100%, 1,3-dimethylimidazolium iodide (10-25%, iodine (2.5-10% and lithium iodide, pyridine derivative and thiocyanate was used as electrolytes in the hybrid solar cell. The different structural, optical and electrical characteristics were measured. The Hybrid solar cell showed a maximum conversion efficiency of 6.51%.

  9. Structural and optical properties of anatase TiO2 heteroepitaxial films prepared by MOCVD

    Science.gov (United States)

    Zhao, Wei; Feng, Xianjin; Xiao, Hongdi; Luan, Caina; Ma, Jin

    2016-11-01

    High-quality single-crystal anatase TiO2(a-TiO2) thin films have been obtained on SrTiO3 (STO) substrates using the metalorganic chemical vapor deposition (MOCVD) method. The optimal preparation process was explored. The lattice structure and epitaxial relationship were investigated by X-ray diffraction (XRD, both θ-2θ and Φ scans) and transmission electron microscopy (TEM). The results indicated that the film prepared at 550 °C with the Ti precursor molar flow rate of 4×10-7 mol/min had the best single crystalline quality, for which a clear epitaxial relationship of a-TiO2 (001)||STO (100) with a-TiO2 [100]||STO [001bar] could be inferred. The elemental composition and proportion were studied by the X-ray photoelectron spectroscopy (XPS) method, which proved the deposited film approximated stoichiometric TiO2. The samples showed high transparency of 70-80% in the visible range.

  10. Layer-by-layer TiO(2)/WO(3) thin films as efficient photocatalytic self-cleaning surfaces.

    Science.gov (United States)

    Patrocinio, Antonio Otavio T; Paula, Leonardo F; Paniago, Roberto M; Freitag, Janna; Bahnemann, Detlef W

    2014-10-08

    New TiO2/WO3 films were produced by the layer-by-layer (LbL) technique and successfully applied as self-cleaning photocatalytic surfaces. The films were deposited on fluorine doped tin oxide (FTO) glass substrates from the respective metal oxide nanoparticles obtained by the sol-gel method. Thirty alternative immersions in pH = 2 TiO2 and pH = 10 WO3 sols resulted in ca. 400 nm thick films that exhibited a W(VI)/Ti(IV) molar ratio of 0.5, as determined by X-ray photoelectron spectroscopy. Scanning electron microscopy, along with atomic force images, showed that the resulting layers are constituted by aggregates of very small nanoparticles (films were investigated by UV-vis spectrophotometry and ultraviolet photoelectron spectroscopy. The films behave as nanoscale heterojunctions, and the presence of WO3 nanoparticles caused a decrease in the optical band gap of the bilayers compared to that of pure LbL TiO2 films. The TiO2/WO3 thin films exhibited high hydrophilicity, which is enhanced after exposition to UV light, and they can efficiently oxidize gaseous acetaldehyde under UV(A) irradiation. Photonic efficiencies of ξ = 1.5% were determined for films constituted by 30 TiO2/WO3 bilayers in the presence of 1 ppm of acetaldehyde, which are ∼2 times higher than those observed for pure LbL TiO2 films. Therefore, these films can act as efficient and cost-effective layers for self-cleaning, antifogging applications.

  11. Photocatalytical Antibacterial Activity of Mixed-Phase TiO2 Nanocomposite Thin Films against Aggregatibacter actinomycetemcomitans.

    Science.gov (United States)

    Yeniyol, Sinem; Mutlu, Ilven; He, Zhiming; Yüksel, Behiye; Boylan, Robert Joseph; Ürgen, Mustafa; Karabuda, Zihni Cüneyt; Basegmez, Cansu; Ricci, John Lawrence

    2015-01-01

    Mixed-phase TiO2 nanocomposite thin films consisting of anatase and rutile prepared on commercially pure Ti sheets via the electrochemical anodization and annealing treatments were investigated in terms of their photocatalytic activity for antibacterial use around dental implants. The resulting films were characterized by scanning electron microscopy (SEM), and X-ray diffraction (XRD). The topology was assessed by White Light Optical Profiling (WLOP) in the Vertical Scanning Interferometer (VSI) mode. Representative height descriptive parameters of roughness R a and R z were calculated. The photocatalytic activity of the resulting TiO2 films was evaluated by the photodegradation of Rhodamine B (RhB) dye solution. The antibacterial ability of the photocatalyst was examined by Aggregatibacter actinomycetemcomitans suspensions in a colony-forming assay. XRD showed that anatase/rutile mixed-phase TiO2 thin films were predominantly in anatase and rutile that were 54.6 wt% and 41.9 wt%, respectively. Craters (2-5 µm) and protruding hills (10-50 µm) on Ti substrates were produced after electrochemical anodization with higher R a and R z surface roughness values. Anatase/rutile mixed-phase TiO2 thin films showed 26% photocatalytic decolorization toward RhB dye solution. The number of colonizing bacteria on anatase/rutile mixed-phase TiO2 thin films was decreased significantly in vitro. The photocatalyst was effective against A. actinomycetemcomitans colonization.

  12. Photocatalytical Antibacterial Activity of Mixed-Phase TiO2 Nanocomposite Thin Films against Aggregatibacter actinomycetemcomitans

    Directory of Open Access Journals (Sweden)

    Sinem Yeniyol

    2015-01-01

    Full Text Available Mixed-phase TiO2 nanocomposite thin films consisting of anatase and rutile prepared on commercially pure Ti sheets via the electrochemical anodization and annealing treatments were investigated in terms of their photocatalytic activity for antibacterial use around dental implants. The resulting films were characterized by scanning electron microscopy (SEM, and X-ray diffraction (XRD. The topology was assessed by White Light Optical Profiling (WLOP in the Vertical Scanning Interferometer (VSI mode. Representative height descriptive parameters of roughness Ra and Rz were calculated. The photocatalytic activity of the resulting TiO2 films was evaluated by the photodegradation of Rhodamine B (RhB dye solution. The antibacterial ability of the photocatalyst was examined by  Aggregatibacter actinomycetemcomitans suspensions in a colony-forming assay. XRD showed that anatase/rutile mixed-phase TiO2 thin films were predominantly in anatase and rutile that were 54.6 wt% and 41.9 wt%, respectively. Craters (2–5 µm and protruding hills (10–50 µm on Ti substrates were produced after electrochemical anodization with higher Ra and Rz surface roughness values. Anatase/rutile mixed-phase TiO2 thin films showed 26% photocatalytic decolorization toward RhB dye solution. The number of colonizing bacteria on anatase/rutile mixed-phase TiO2 thin films was decreased significantly in vitro. The photocatalyst was effective against A. actinomycetemcomitans colonization.

  13. Photocatalytic Nanocomposite Films Fabricated by Layer-by-Layer Self-assembly of TiO2 Nanoparticles and Lignosulfonates

    Institute of Scientific and Technical Information of China (English)

    李辉; 付时雨; 彭林才; 詹怀宇

    2012-01-01

    Photocatalytic multilayer nanocomposite films composed of anatase TiO2 nanoparticles and lignosulfonates (LS) were fabricated on quartz slides by the layer-by-layer (LBL) self-assembly technique. X-ray photoelectron spectroscopy (XPS), UV-vis spectroscopy and atomic force microscopy (AFM) were used to characterize the TiO2/LS multilayer nanocomposite films. Moreover, the photocatalytic properties (decomposition of methyl orange and bacteria) of multilayer nanocomposite films were investigated. XPS results indicated that the intensities of titanium and sulfur peaks increased with the LBL deposition process. A linear increase in absorbance at 280 nm was found by UV-Vis spectroscopy, suggesting that stepwise multilayer growth occurs on the substrate and this deposition process is highly reproducible. AFM images showed that quartz slide was completely covered by TiO2 nanoparticles when a 10-bilayer multilayer film was formed. The decomposition efficiency of methyl orange by TiOz/LS multilayer films under the same UV irradiation time increased linearly with the number of TiO2 layers, and the results of decomposition of bacteria under UV irradiation showed that TiO2/LS multilayer nanocomposite films exhibited excellent decomposition activity of bacteria (Escherichia coil).

  14. In situ formation of nanometer-scale TiO2/SiC functional compositional film on carbon fiber

    Institute of Scientific and Technical Information of China (English)

    ZHOU Chunhua; YIN Yansheng; ZHANG Shuxiang; LIU Wei

    2005-01-01

    In the toluene solution of the precursor Polycarbosilane (PCS) containing low- molecular-mass additive Ti(OC4H9)4, TiO2/SiC nanometer-scale functional compositional film with the surface TiO2 layer on CF was formed in situ by means of polymer-derived precursors. The effects of Ti (OC4H9)4 concentrations and the maturating time were studied on the densification and TiO2 particle size of surface layer. The compositions of film were TiO2 and SiC crystal by XRD. According to the results of ESCA analysis, Ti(OC4H9)4 compound oozed gradiently from the pre-ceramic PCS to the surface layer after maturating time of 100 h. In the conditions of 45wt% Ti (OC4H9)4 and 100 h maturation, the nanometer-scale TiO2 particles on continuous surface layer were formed by SEM photographs. The nanometer-scale TiO2/SiC functional compositional film can modify the resistance to oxidation of carbon fiber.

  15. Enhanced Osteogenic Activity of TiO2 Nanorod Films with Microscaled Distribution of Zn-CaP.

    Science.gov (United States)

    He, Meng; Chen, Xiaoyi; Cheng, Kui; Weng, Wenjian; Wang, Huiming

    2016-03-23

    The topography at the micro-/nanoscale level and bioactive composition of material surfaces have been thought to play vital roles in their interactions with cells. However, it is still a challenge to further modify special topography with biodegradable composition or vice versa. In this study, TiO2 nanorod films covered with microscale-distributed Zn-containing calcium phosphate (Zn-CaP) were prepared, trying to create a micro-/nanoscale topography and Zn(2+) release capability. MC3T3-E1 cells cultured on TiO2 nanorod film with sparsely distributed Zn-CaP (TiO2/S-ZCP) had significantly higher biological responses than those on the films with densely distributed Zn-CaP (TiO2/D-ZCP) and fully covered Zn-CaP (F-ZCP). TiO2/S-ZCP film was demonstrated to facilitate osteogenic differentiation much more strongly than F-ZCP and TiO2/D-ZCP films based on evaluations of ALP, related gene expressions, and extracellular matrix mineralization. The higher osteogenic differentiation on TiO2/S-ZCP film is ascribed to the micro-/nanoscale topography from Zn-CaP coverage promoting cell adhesion and filopodia extension, and inducing differentiation-orientation in the initial stage. And consequently Zn(2+) release results in enhancement of differentiation. Therefore, we believe that better organization of the micro-/nanotopography and bioactive ion release on the surface would be a promising way to enhance osteogenic activity for orthopedic and dental implants.

  16. Si microwire array photoelectrochemical cells: Stabilized and improved performances with surface modification of Pt nanoparticles and TiO2 ultrathin film

    Science.gov (United States)

    Yan, Jimu; Wu, Shaolong; Zhai, Xiongfei; Gao, Xiang; Li, Xiaofeng

    2017-02-01

    To achieve the semiconductor photoelectrochemical (PEC) cells targeting the industry applications with commercial competitiveness, high efficiency and good stability are requisite properties. To improve the PEC response, the vertically-aligned silicon microwire arrays (SiMWAs) modified with isolated Pt nanoparticles (PtNPs) and conformal TiO2 ultrathin film (TiO2/Pt@SiMWAs) are fabricated and examined in this study. The modified system shows the significantly enhanced responses and operation stability, that is, an enhancement of ∼30.0% in saturation photocurrent density (Jsat), a cathodic shift of ∼0.85 V (relative to the bare SiMWAs) in applied potential for Jsat, and an attenuation ratio of the photocurrent <1.5% during 1800-sec-continuous operation in an aqueous electrolyte. The underlying mechanisms are attributed to: (1) PtNPs concentrate the incident photons, promote the photo-carrier separation, and catalyze the chemical reaction at the photoelectrode-electrolyte interfaces; (2) conformal TiO2 ultrathin film protects the SiMWAs from photo-oxidation/corrosion as well as suppresses the surface recombination. Our results indicate a feasible route for the practical applications of oxidizable and corrodible semiconductor micro-/nanostructures in the fields of PEC solar cells, water splitting, photodegradation, and so on.

  17. p-Type hydrogen sensing with Al- and V-doped TiO2 nanostructures

    Science.gov (United States)

    Li, Zhaohui; Ding, Dongyan; Ning, Congqin

    2013-01-01

    Doping with other elements is one of the efficient ways to modify the physical and chemical properties of TiO2 nanomaterials. In the present work, anatase TiO2 nanofilms doped with Al and V elements were fabricated through anodic oxidation of Ti6Al4V alloy and further annealing treatment. Hydrogen sensing behavior of the crystallized Ti-Al-V-O nanofilms at various working temperatures was investigated through exposure to 1,000 ppm H2. Different from n-type hydrogen sensing characteristics of undoped TiO2 nanotubes, the Al- and V-doped nanofilms presented a p-type hydrogen sensing behavior by showing increased resistance upon exposure to the hydrogen-containing atmosphere. The Ti-Al-V-O nanofilm annealed at 450°C was mainly composed of anatase phase, which was sensitive to hydrogen-containing atmosphere only at elevated temperatures. Annealing of the Ti-Al-V-O nanofilm at 550°C could increase the content of anatase phase in the oxide nanofilm and thus resulted in a good sensitivity and resistance recovery at both room temperature and elevated temperatures. The TiO2 nanofilms doped with Al and V elements shows great potential for use as a robust semiconducting hydrogen sensor.

  18. Nanostructured TiO2 and ZnO prepared by using pressurized hot water and their eco-toxicological evaluation

    Science.gov (United States)

    Troppová, Ivana; Matějová, Lenka; Sezimová, Hana; Matěj, Zdeněk; Peikertová, Pavlína; Lang, Jaroslav

    2017-06-01

    The eco-toxicological effects of unconventionally prepared nanostructured TiO2 and ZnO were evaluated in this study, since both oxides are keenly investigated semiconductor photocatalysts in the last three decades. Unconventional processing by pressurized hot water was applied in order to crystallize oxide materials as an alternative to standard calcination. Acute biological toxicity of the synthesized oxides was evaluated using germination of Sinapis alba seed (ISO 11269-1) and growth of Lemna minor fronds (ISO 20079) and was compared to commercially available TiO2 Degussa P25. Toxicity results revealed that synthesized ZnO as well as TiO2 is toxic contrary to commercial TiO2 Degussa P25 which showled stimulation effect to L. minor and no toxicity to S. alba. ZnO was significantly more toxic than TiO2. The effect of crystallite size was considered, and it was revealed that small crystallite size and large surface area are not the toxicity-determining factors. Factors such as the rate of nanosized crystallites aggregation and concentration, shape and surface properties of TiO2 nanoparticles affect TiO2 toxicity to both plant species. Seriously, the dissolution of Ti4+ ions from TiO2 was also observed which may contribute to its toxicity. In case of ZnO, the dissolution of Zn2+ ions stays the main cause of its toxicity.

  19. Hybrid functional IrO2-TiO2 thin film resistor prepared by atomic layer deposition for thermal inkjet printheads

    Institute of Scientific and Technical Information of China (English)

    Won-Sub KWACK; Hyoung-Seok MOON; Seong-Jun JEONG; Qi-min WANG; Se-Hun KWON

    2011-01-01

    IrO2-TiO2 thin films were prepared by atomic layer deposition using Ir(EtCp)(COD) and titanium isopropoxide (TTIP).in the IrO2-TiO2 thin films. The low temperature coefficient of resistance(TCR) values can be obtained by adopting IrO2-TiO2 composite thin films. Moreover, the change in the resistivity of lrO2-TiO2 thin films was below 10% even after O2 annealing process at 600 ℃. The step stress test results show that IrO2-TiO2 films have better characteristics than conventional TaN08 heater resistor.Therefore, IrO2-TiO2 composite thin films can be used as a heater resistor material in thermal inkjet printhead.

  20. Heterogeneous Deposition of Cu2O Nanoparticles on TiO2 Nanotube Array Films in Organic Solvent

    Directory of Open Access Journals (Sweden)

    Xinwen Huang

    2013-01-01

    Full Text Available A novel method for decoration of anodic TiO2 nanotube array films (NAFs with Cu2O nanoparticles has been reported. The method is based on the reduction of Cu(II in a mixture of ethylene glycol and N,N-dimethylformamide at 120°C for 16 h, where the resulting Cu2O can heterogeneously nucleate and grow on TiO2 NAFs. The nanosized Cu2O is found to be well dispersed on the wall of TiO2 nanotubes without blocking the nanotube, a commonly observed phenomenon in the case of deposition of Cu2O via electrochemical method. The amount of Cu2O deposited on the TiO2 NAFs can be varied by adjusting the concentration of Cu(II in the organic solution. UV-vis spectra measurement indicates that the decoration of TiO2 NAFs with Cu2O nanoparticles greatly improves their ability to respond to visible light. By examining the photocurrent and photodegradation of methyl orange under simulated sunlight, it is found that these Cu2O-decorated TiO2 NAFs show much more photoactive in comparison with the as-prepared TiO2 NAFs.

  1. OPTICAL CHARACTERIZATION OF TiO2 THIN FILM ON SILICON SUBSTRATE DEPOSITED BY DC REACTIVE MAGNETRON SPUTTERING

    Institute of Scientific and Technical Information of China (English)

    H.Q. Wang; H. Shen; D.C. Ba; B.W. Wang; L.S. Wen; D. Chen

    2005-01-01

    TiO2 thin film has attracted considerable attention in recent years, due to its different refractive index and transparency with amorphous and different crystals in the visible and near-infrared wavelength region, high dielectric constant, wide band gap, high wear resistance and stability, etc, for which make it being used in many fields. This paper aims to investigate the optical characterization of thin film TiO2 on silicon wafer. The TiO2 thin films were prepared by DC reactive magnetron sputtering process from Ti target. The reflectivity of the films was measured by UV-3101PC, and the index of refraction (n) and extinction coefficient (k) were measured by n & k Analyzer 1200.

  2. 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.

  3. Study of nanoparticles TiO2 thin films on p-type silicon substrate using different alcoholic solvents

    Science.gov (United States)

    Muaz, A. K. M.; Hashim, U.; Arshad, M. K. Md.; Ruslinda, A. R.; Ayub, R. M.; Gopinath, Subash C. B.; Voon, C. H.; Liu, Wei-Wen; Foo, K. L.

    2016-07-01

    In this paper, sol-gel method spin coating technique is adopted to prepare nanoparticles titanium dioxide (TiO2) thin films. The prepared TiO2 sol was synthesized using titanium butoxide act as a precursor and subjected to deposited on the p-type silicon oxide (p-SiO2) and glass slide substrates under room temperature. The effect of different alcoholic solvents of methanol and ethanol on the structural, morphological, optical and electrical properties were systematically investigated. The coated TiO2 thin films were annealed in furnace at 773 K for 1 h. The structural properties of the TiO2 films were examined with X-ray Diffraction (XRD). From the XRD analysis, both solvents showing good crystallinity with anatase phase were the predominant structure. Atomic Force Microscopy (AFM) was employed to study the morphological of the thin films. The optical properties were investigated by Ultraviolet-visible (UV-Vis) spectroscopy were found that ethanol as a solvent give a higher optical transmittance if compare to the methanol solvent. The electrical properties of the nanoparticles TiO2 thin films were measured using two-point-probe technique.

  4. High-Quality Fe-doped TiO2 films with Superior Visible-Light Performance

    DEFF Research Database (Denmark)

    Su, Ren; Bechstein, Ralf; Kibsgaard, Jakob

    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...

  5. Mechanism of Enhanced Performance of Dye-Sensitized Solar Cell Based TiO2 Films Treated by Titanium Tetrachloride

    Institute of Scientific and Technical Information of China (English)

    曾隆月; 戴松元; 王孔嘉; 潘旭; 史成武; 郭力

    2004-01-01

    Performance of dye-sensitized solar cells can be improved by treating the nanoporous TiO2 films with titanium tetrachloride (TiCl4) aqueous solution. We explore the reason why the performance of dye-sensitized solar cells is enhanced by this method. It is found that the effect of TiCl4 treatment not only reduces the films surface area and improves the electronic contact, but also enhances the binding of N719 with the TiO2 films surface.

  6. Structure and Oxygen Sensing Properties of TiO2 Porous Semiconductor Thin Films

    Institute of Scientific and Technical Information of China (English)

    JI Huiming; L(U) Ying; MA Shicai; LI Yan

    2007-01-01

    Semiconductor-type TiO2 oxygen sensing thin films were synthesized using tetrabutyl titanate ( Ti(OBu)4 ) as precursor and diethanolamine (DEA) as complexing agent by the sol-gel process. The porous and oxygen sensing TiO2 films were obtained by the addition of polyethylene glycol (PEG). The micrographs of scanning electron microscope (SEM) show that the pores of the sample about 400-600 nm in size with PEG(2 000 g/mol) are larger than those about 300 nm in size with PEG( 1 000 g/mol), while the density of pores is lower. The results also indicate that increasing the content of PEG properly is beneficial to the formation of porous structure. With the increasing content of PEG from 0 g to 2.5 g, the oxygen sensitivity increases from 330 to more than 1 000 at 800 ℃, from 170 to more than 1 000 at 900 ℃, and the response time to O2 and H2 are about 1.5 s and less than l s, respectively.

  7. Photocatalytic degradation of phenol in aqueous solution using TiO2/Ti thin film photocatalyst

    Institute of Scientific and Technical Information of China (English)

    樊彩梅; 孙彦平; 闵延琴; 郝晓刚; 李新军; 李芳柏

    2003-01-01

    In order to clarify the respective role of the UV light, catalyst, external bias as well as their combined effects on the photodegradation process and to clarify the photocatalytic mechanism under different experimental conditions, a series of experiments were conducted in a shallow pond photoreactor with an effective volume of 100 mL using TiO2/Ti thin film prepared by anodization as photocatalyst. A 300W UV lamp(Emax=365 nm)was used as side light source. The effect of light intensity on photocatalysis was also conducted. The results show that photocatalytic oxidation is an effective method for phenol removal from waters. The degradation rate can be improved by applying an anodic bias to the TiO2/Ti film electrode, phenol can not be decomposed under only 365 nm UV light irradiation even in the presence of hydrogen peroxide. In the range of our research, the phenol removal rate can be described in terms of pseudo-first order kinetics.

  8. Surface enhanced Raman scattering activity of TiN thin film prepared via nitridation of sol-gel derived TiO2 film

    Science.gov (United States)

    Dong, Zhanliang; Wei, Hengyong; Chen, Ying; Wang, Ruisheng; Zhao, Junhong; Lin, Jian; Bu, Jinglong; Wei, Yingna; Cui, Yi; Yu, Yun

    2015-10-01

    Surface-enhanced Raman scattering (SERS) is a powerful and non-destructive analytical technique tool for chemical and biological sensing applications. Metal-free SERS substrates have recently been developed by using semiconductor nanostructures. The optical property of TiN film is similar to that of gold. Besides that, its good chemical inertness and thermodynamic stability make TiN thin film an excellent candidate for SERS. In order to investigate its SERS activity, the TiN thin film was successfully prepared via direct nitridation of the sol-gel derived TiO2 thin film on the quartz substrate using ammonia gas as reducing agent. The crystallite structures and morphology of TiN thin film were determined by XRD, RAMAN and FE-SEM. The results show that the thin film obtained is cubic titanium nitride with a lattice parameter of 4.2349 Å. The surface of TiN thin film is rough and with the particles of 50 nm in average sizes. The thickness of TiN thin film is about 130 nm. The TiN thin film displays a surface Plasmon resonance absorption peak at around 476 nm, which can lead to a strong enhancement of the EM field on the interface. The Raman signal of the probe molecule R6G was greatly enhanced through TiN thin film substrates. The enhancement factor is about 4.1×103 and the detection limit achieves 10-6 M for R6G. The TiN thin film substrate also shows a good reproducibility of SERS performance. The results indicate that TiN thin film is an attractive material with potential application in SERS substrates.

  9. Photocatalytic degradation of dimethoate using LbL fabricated TiO2/polymer hybrid films.

    Science.gov (United States)

    Priya, D Neela; Modak, Jayant M; Trebše, Polonca; Zabar, Romina; Raichur, Ashok M

    2011-11-15

    Degradation of dimethoate under UV irradiation using TiO(2)/polymer films prepared by the layer-by-layer (LbL) method was investigated. The thin films were fabricated on glass slides and the surface morphology and roughness of the thin films were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The effect of lamp intensity, catalyst loading in the layers, number of bilayers, pH and initial dimethoate concentration on the degradation of dimethoate was systematically studied. The degradation was monitored using high performance liquid chromatography (HPLC) analysis and total organic carbon (TOC) measurements as a function of irradiation time, to see the change in concentration of dimethoate and mineralization, respectively. Complete degradation of dimethoate was achieved under TiO(2) optimum loading of 4 g/L at an UV irradiation time of 180 min. Increase in the lamp intensity, catalyst loading and number of bilayers increased the rate of degradation. At a pH of 4.62, complete degradation of dimethoate was observed. The degradation efficiency decreased with increase in initial dimethoate concentration. The degradation byproducts were analyzed and confirmed by gas chromatography-mass spectra (GC-MS). Toxicity of the irradiated samples was measured using the luminescence of bacteria Vibrio fischeri after 30 min of incubation and the results showed more toxicity than the parent compound. Catalyst reusability studies revealed that the fabricated thin films could be repeatedly used for up to ten times without affecting the photocatalytic activity of the films. The findings of the present study are very useful for the treatment of wastewaters contaminated with pesticides.

  10. Nb-doped TiO2 thin films as photocatalytic materials

    Indian Academy of Sciences (India)

    Catalin Adomnitei; Sorin Tascu; Dumitru Luca; Marius Dobromir; Mihaela Girtan; Diana Mardare

    2015-09-01

    Amorphous undoped and Nb-doped films were obtained by the spin coating method. The films have a compact structure, as revealed by scanning electron microscopy, and are very thin, with thickness values under 100 nm. The photocatalytic activity of the films was evaluated by observing the decomposition of an oleic acid solution under UV irradiation, and by studying the change in the optical transmittance of an aqueous solution containing methylene blue, in the presence of the UV-irradiated films. More than 30 h, depending on doping, are needed to recover their initial contact angles before applying oleic acid. The increase of the optical transmittance of the methylene blue solution confirms the photocatalytic degradation of methylene blue on the Nb-doped TiO2 films. X-ray photoelectron spectroscopy studies, performed to detect the presence of the carbon on the irradiated surface of the films, drive to the conclusion that at the surface of the films, even for contact angles close to 0°, the presence of carbon still can be detected, which demonstrates that hydrophilicity is ruled by a different mechanism than photocatalysis.

  11. Self-assembled Bi2MoO6/TiO2 nanofiber heterojunction film with enhanced photocatalytic activities

    Science.gov (United States)

    Li, Hua; Zhang, Tianxi; Pan, Chao; Pu, Chenchen; Hu, Yang; Hu, Xiaoyun; Liu, Enzhou; Fan, Jun

    2017-01-01

    TiO2 nanofiber film (TiO2 NFF) was successfully fabricated by an ethylene glycol-assisted hydrothermal method, and then self-assembled flake-like Bi2MoO6 was grown on the surface of TiO2 nanofiber under alcohol thermal condition. The investigations indicate that the nanofiber structure of TiO2 films exhibits excellent visible light scattering property, the scattering light overlaps with the absorption band of Bi2MoO6, which can enhance the utility of incident light. The prepared Bi2MoO6/TiO2 composites show obviously enhanced photocatalytic activity for methylene blue (MB) degradation compared with pure TiO2 nanofiber under visible light irradiation (λ > 420 nm). The enhanced photocatalytic activity is primarily attributed to the synergistic effect of visible light absorption and effective electron-hole separation at the interfaces of the two semiconductors, which is confirmed by photoluminescence (PL) and electrochemical tests.

  12. CdSe nanocrystal sensitized anatase TiO2 (001) tetragonal nanosheet-array films for photovoltaic application.

    Science.gov (United States)

    Feng, Shuanglong; Yang, Junyou; Liu, Ming; Liu, Yong

    2013-02-01

    CdSe nanocrystal sensitized TiO2 nanosheet array heterostructure films were fabricated by a two-step method. Firstly, a single crystalline anatase TiO2 tetragonal nanosheet-array film on a transparent conductive fluorine-doped tin oxide (FTO) substrate was successfully prepared by hydrothermal method. Then, CdSe nanocrystalline sensitizers were deposited on the TiO2 nanosheet array by CBD method. The products were characterized with XRD, SEM, TEM and UV-vis absorption spectroscopy. The effect of the CdSe nanocrystal deposition time and the length of the TiO2 sheet on the photovoltaic performance of the resulting CdSe/TiO2 nanosheet array electrodes were also investigated. In comparison with the non-sensitized TiO2 nanosheet array, the photocurrent of CdSe sensitized TiO2 nanosheet has a great enhancement, which gives some insight to the fundamental mechanism of the performance improvement.

  13. Synthesis of Ag ion-implanted TiO2 thin films for antibacterial application and photocatalytic performance.

    Science.gov (United States)

    Hou, Xinggang; Ma, Huiyan; Liu, Feng; Deng, Jianhua; Ai, Yukai; Zhao, Xinlei; Mao, Dong; Li, Dejun; Liao, Bin

    2015-12-15

    TiO2 thin films were deposited by spin coating method. Silver ions were implanted into the films using a Metal Vapor Vacuum Arc implanter. The antibacterial ability of implanted films was tested using Escherichia coli removal under fluorescent irradiation and in the dark. The concentration of E. coli was evaluated by plating technique. The photocatalytic efficiency of the implanted films was studied by degradation of methyl orange under fluorescent illumination. The surface free energy of the implanted TiO2 films was calculated by contact angle testing. Vitamin C was used as radical scavengers to explore the antibacterial mechanism of the films. The results supported the model that both generation of reactive oxygen species and release of silver ions played critical roles in the toxic effect of implanted films against E. coli. XPS experimental results demonstrated that a portion of the Ag(Ag(3+)) ions were doped into the crystalline lattice of TiO2. As demonstrated by density functional theory calculations, the impurity energy level of subtitutional Ag was responsible for enhanced absorption of visible light. Ag ion-implanted TiO2 films with excellent antibacterial efficiency against bacteria and decomposed ability against organic pollutants could be potent bactericidal surface in moist environment. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. 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.

  15. Enhanced apatite-forming ability and cytocompatibility of porous and nanostructured TiO2/CaSiO3 coating on titanium.

    Science.gov (United States)

    Hu, Hongjie; Qiao, Yuqin; Meng, Fanhao; Liu, Xuanyong; Ding, Chuanxian

    2013-01-01

    To improve the bioactivity and cytocompatibility of biomedical titanium dioxide coating, many efforts have been made to modify its surface composition and topography. Meanwhile, CaSiO(3) was commonly investigated as coating material on titanium implants for fast fixation and firm implant-bone attachment due to its demonstrated bioactivity and osteointegration. In this work, gradient TiO(2)/CaSiO(3) coating on titanium was prepared by a two-step procedure, in which porous and nanostructured TiO(2) coating on titanium was prepared by plasma electrolytic oxidation in advance, and then needle and flake-like CaSiO(3) nanocrystals were deposited on the TiO(2) coating surface by electron beam evaporation. In view of the potential clinical applications, apatite-forming ability of the TiO(2)/CaSiO(3) coating was evaluated by simulated body fluid (SBF) immersion tests, and MG63 cells were cultured on the surface of the coating to investigate its cytocompatibility. The results show that deposition of CaSiO(3) significantly enhanced the apatite-forming ability of nanostructured TiO(2) coating in SBF. Meanwhile, the MG63 cells on TiO(2)/CaSiO(3) coating show higher proliferation rate and vitality than that on TiO(2) coating. In conclusion, the porous and nanostructured TiO(2)/CaSiO(3) coating on titanium substrate with good apatite-forming ability and cytocompatibility is a potential candidate for bone tissue engineering and implant coating. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Estudo das propriedades acusticas do filme finode TiO2 usando SAW

    OpenAIRE

    Glaucio Pedro de Alcantara

    2005-01-01

    Resumo: Este trabalho de dissertação apresenta o estudo e projeto dos elementos que compõem um sensor de gases baseado na tecnologia de Onda Acústica de Superfície (SAW), tais como, o oscilador colpitts SAW e um ressonador SAW de uma porta, os quais estão na malha de realimentação de um amplificador. Foi realizado também a deposição de diferentes espessuras de filme fino de TiO2 sobre o sensor, a fim de se estudar o efeito da atenuação da SAW na fronteira entre o cristal e o filme. É mo...

  17. Characterization thin films TiO2 obtained in the magnetron sputtering process

    Science.gov (United States)

    Kamiński, Maciej; Firek, Piotr; Caban, Piotr

    2016-12-01

    The aim of the study was to elucidate influence parameters of magnetron sputtering process on growth rate and quality of titanium dioxide thin films. TiO2 films were produced on two inch silicon wafers by means of magnetron sputtering method. Characterization of samples was performed using ellipsometer and atomic force microscope (AFM). Currentvoltage (I-V) and capacitance-voltage (C-V) measurements were also carried out. The results enable to determine impact of pressure, power, gases flow and process duration on the physical parameters obtained layers such as electrical permittivity, flat band voltage and surface topography. Experiments were designed according to orthogonal array Taguchi method. Respective trends impact were plotted.

  18. Laser-induced electron transfer desorption/ionization of metal complexes on TiO2 films

    Science.gov (United States)

    Grechnikov, A. A.; Georgieva, V.; Borodkov, A. S.; Nikiforov, S. M.; Raicheva, Z.; Lazarov, J.; Donkov, N.

    2014-12-01

    Thin titanium dioxide (TiO2) films were studied as ion emitters for the laser-induced electron transfer desorption/ionization (LETDI) of metal complexes with organic reagents. The TiO2 films (350 nm thick) were deposited on the silicon substrates by e-beam evaporation of TiO2 powder. Copper complex with phthalocyanine, rhenium complex with thiocarbanilide and platinum complex with 8-quinolinethiol were studied as the test analytes. Reflectron time-of- flight mass spectrometer with the rotating ball interface was used for analysis. The analytes were applied on the surface of TiO2 film using an electrospray deposition. All tested compounds are detected as the radical molecular ions with no fragmentation. It is found, that TiO2 films are very stable and show good sensitivity in examined range of the analyte concentrations. The limits of detection of studied complexes were at the subfemtomole range, and the relative standard deviation was less than 10%.

  19. Influence of Nd-Doping on Photocatalytic Properties of TiO2 Nanoparticles and Thin Film Coatings

    Directory of Open Access Journals (Sweden)

    Damian Wojcieszak

    2014-01-01

    Full Text Available Structural, optical, and photocatalytic properties of TiO2 and TiO2:Nd nanopowders and thin films composed of those materials have been compared. Titania nanoparticles with 1, 3, and 6 at. % of Nd-dopant were synthesized by sol-gel method. Additionally, thin films with the same material composition were prepared with the aid of spin-coating method. The analysis of structural investigations revealed that all as-prepared nanopowders were nanocrystalline and had TiO2-anatase structure. The average size of crystallites was ca. 4-5 nm and the correlation between the amount of neodymium and the size of TiO2 crystallites was observed. It was shown that the dopant content influenced the agglomeration of the nanoparticles. The results of photocatalytic decomposition of MO showed that doping with Nd (especially in the amount of 3 at. % increased self-cleaning activity of the prepared titania nanopowder. Similar effect was received in case of the thin films, but the decomposition rate was lower due to their smaller active surface area. However, the as-prepared TiO2:Nd photocatalyst in the form of thin films or nanopowders seems to be a very attractive material for various applications.

  20. Dye-sensitized solar cells based on anatase TiO 2 hollow spheres/carbon nanotube composite films

    Science.gov (United States)

    Yu, Jiaguo; Fan, Jiajie; Cheng, Bei

    Dye-sensitized solar cells (DSSCs) based on anatase TiO 2 hollow spheres (TiO2HS)/multi-walled carbon nanotubes (CNT) nanocomposite films are prepared by a directly mechanical mixing and doctor blade method. The prepared samples are characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, UV-vis absorption spectroscopy and N 2 adsorption-desorption isotherms. The photoelectric conversion performances of the DSSCs based on TiO2HS/CNT composite film electrodes are also compared with commercial-grade Degussa P25 TiO 2 nanoparticles (P25)/CNT composite solar cells at the same film thickness. The results indicate that the photoelectric conversion efficiencies (η) of the TiO2HS/CNT composite DSSCs are dependent on CNT loading in the electrodes. A small amount of CNT clearly enhances DSSC efficiency, while excessive CNT loading significantly lowers their performance. The former is because CNT enhance the transport of electrons from the films to FTO substrates. The latter is due to high CNT loading shielding the visible light from being adsorbed by dyes.

  1. Stereospecific growth of densely populated rutile mesoporous TiO2 nanoplate films: a facile low temperature chemical synthesis approach

    Science.gov (United States)

    Lee, Go-Woon; Ambade, Swapnil B.; Cho, Young-Jin; Mane, Rajaram S.; Shashikala, V.; Yadav, Jyotiprakash; Gaikwad, Rajendra S.; Lee, Soo-Hyoung; Jung, Kwang-Deog; Han, Sung-Hwan; Joo, Oh-Shim

    2010-03-01

    We report for the first time, using a simple and environmentally benign chemical method, the low temperature synthesis of densely populated upright-standing rutile TiO2 nanoplate films onto a glass substrate from a mixture of titanium trichloride, hydrogen peroxide and thiourea in triply distilled water. The rutile TiO2 nanoplate films (the phase is confirmed from x-ray diffraction analysis, selected area electron diffraction, energy-dispersive x-ray analysis, and Raman shift) are 20-35 nm wide and 100-120 nm long. The chemical reaction kinetics for the growth of these upright-standing TiO2 nanoplate films is also interpreted. Films of TiO2 nanoplates are optically transparent in the visible region with a sharp absorption edge close to 350 nm, confirming an indirect band gap energy of 3.12 eV. The Brunauer-Emmet-Teller surface area, Barret-Joyner-Halenda pore volume and pore diameter, obtained from N2 physisorption studies, are 82 m2 g - 1, 0.0964 cm3 g - 1 and 3.5 nm, respectively, confirming the mesoporosity of scratched rutile TiO2 nanoplate powder that would be ideal for the direct fabrication of nanoscaled devices including upcoming dye-sensitized solar cells and gas sensors.

  2. Influence of Operating Parameters on Surface Properties of RF Glow Discharge Oxygen Plasma Treated TiO2/PET Film for Biomedical Application

    Science.gov (United States)

    Thin transparent titania (TiO2) films were coated on the surface of flexible poly (ethylene terephthalate) (PET) surface using standard sol gel techniques. The TiO2/PET thin film surfaces were further modified by exposing the films to a RF glow discharge oxygen plasma. The exposu...

  3. Influence of Operating Parameters on Surface Properties of RF Glow Discharge Oxygen Plasma Treated TiO2/PET Film for Biomedical Application

    Science.gov (United States)

    Thin transparent titania (TiO2) films were coated on the surface of flexible poly (ethylene terephthalate) (PET) surface using standard sol gel techniques. The TiO2/PET thin film surfaces were further modified by exposing the films to a RF glow discharge oxygen plasma. The exposu...

  4. Structure and Surface Characterization of Nanostructured Tio2 Coatings Deposited Via HVOF Thermal Spray Processes

    Directory of Open Access Journals (Sweden)

    Maryamossadat Bozorgtabar

    2015-01-01

    Full Text Available Titanium dioxide coatings were deposited by high velocity oxy-fuel spraying (HVOF with the use of agglomerated P25/20 nano-powder and different spraying parameters (e.g. fuel/flow ratio to determine their influence on the microstructure, crystalline structure and surface feature of the coatings. The microstructure of as-sprayed TiO2 coatings was characterized by scanning electron microscope (SEM, transmission electron microscope (TEM and X-ray diffraction (XRD. Surface features were investigated by Fourier transform infrared (FT-IR and X-ray photoelectron spectroscopy (XPS. The results showed that the fuel and oxygen flow ratio have an important influence on the microstructure, anatase content, surface chemical state and surface feature of the TiO2 coatings

  5. Laser assembly nanostructured Al2O3/TiO2 coating on cast aluminum surface

    Institute of Scientific and Technical Information of China (English)

    ZHANG Guang-jun; DAI Jian-qiang; WANG Hui-ping; YAN Min-jie; XI Wen-long; ZOU Chang-gu; GE Da-fang

    2004-01-01

    CO2 laser quick assembly technology is adopted on the surface of cast aluminum ZL104 to form a dense ceramic coating containing a great deal of nanometer Al2O3/TiO2 particles which eliminate cracks and porosities.The major phases of the coating are α-Al2O3 andβ-TiO2. The micro-hardness distribution of the coating is 1 813,1 504, 1 485 and 1 232 (HV0.05). The bonding strength of the coating LC1 is 11.4 N, which is 7.26 times higher than that of the conventional hot-spraying Al2O3/TiO2 coating. It has been proved by analysis that the bonding strength is achieved because of the effects of both super-quick laser consolidation and the nanometer effect of nanometer ceramic material.

  6. PREPARATION AND SURFACE CHARACTERIZATION OF TiO2 THIN FILMS ON GLASS BY MAGNETRON SPUTTERING METHOD

    Institute of Scientific and Technical Information of China (English)

    L.S. Yin; H. Shen; J.X. Zhang

    2002-01-01

    Ti thin films were firstly deposited on glass substrates by magnetron sputtering method,then sintered the Ti thin films in air atmosphere and finally TiO2 transparence thinfilms on glass substrates were obtained. The structure and surface morphologies ofthe thin films were characterized by X-ray diffraction and SEM. The growth processof the thin filns has been observed. The annealing time and annealing temperatureshave an affect on the growth of the films.

  7. Comparative Solid Phase Photocatalytic Degradation of Polythene Films with Doped and Undoped TiO2 Nanoparticles

    Directory of Open Access Journals (Sweden)

    Wasim Asghar

    2011-01-01

    Full Text Available Comparative photocatalytic degradation of polythene films was investigated with undoped and metal (Fe, Ag, and Fe/Ag mix doped TiO2 nanoparticles under three different conditions such as UV radiation, artificial light, and darkness. Prepared photocatalysts were characterized by XRD, SEM, and EDS techniques. Photocatalytic degradation of the polythene films was determined by monitoring their weight reduction, SEM analysis, and FTIR spectroscopy. Weight of PE films steadily decreased and led to maximum of 14.34% reduction under UV irradiation with Fe/Ag mix doped TiO2 nanoparticles and maximum of 14.28% reduction under artificial light with Ag doped TiO2 nanoparticles in 300 hrs. No weight reduction was observed under darkness. Results reveal that polythene-TiO2 compositing with metal doping has the potential to degrade the polythene waste under irradiation without any pollution.

  8. Rough gold films as broadband absorbers for plasmonic enhancement of TiO2 photocurrent over 400-800 nm

    Science.gov (United States)

    Tan, Furui; Li, Tenghao; Wang, Ning; Lai, Sin Ki; Tsoi, Chi Chung; Yu, Weixing; Zhang, Xuming

    2016-09-01

    Recent years have witnessed an increasing interest in highly-efficient absorbers of visible light for the conversion of solar energy into electrochemical energy. This study presents a TiO2-Au bilayer that consists of a rough Au film under a TiO2 film, which aims to enhance the photocurrent of TiO2 over the whole visible region and may be the first attempt to use rough Au films to sensitize TiO2. Experiments show that the bilayer structure gives the optimal optical and photoelectrochemical performance when the TiO2 layer is 30 nm thick and the Au film is 100 nm, measuring the absorption 80-90% over 400-800 nm and the photocurrent intensity of 15 μA·cm-2, much better than those of the TiO2-AuNP hybrid (i.e., Au nanoparticle covered by the TiO2 film) and the bare TiO2 film. The superior properties of the TiO2-Au bilayer can be attributed to the rough Au film as the plasmonic visible-light sensitizer and the photoactive TiO2 film as the electron accepter. As the Au film is fully covered by the TiO2 film, the TiO2-Au bilayer avoids the photocorrosion and leakage of Au materials and is expected to be stable for long-term operation, making it an excellent photoelectrode for the conversion of solar energy into electrochemical energy in the applications of water splitting, photocatalysis and photosynthesis.

  9. Nanostructured Silica-Gel Doped with TiO2 for Mercury Vapor Control

    Science.gov (United States)

    Pitoniak, Erik; Wu, Chang-Yu; Londeree, Danielle; Mazyck, David; Bonzongo, Jean-Claude; Powers, Kevin; Sigmund, Wolfgang

    2003-08-01

    A novel high surface area SiO2-TiO2 composite has been developed for elemental mercury vapor removal from combustion sources. The composite exhibits synergistic adsorption and photocatalytic oxidation. Mercury vapor in the gas stream is adsorbed, oxidized and stays on the composite. The composite has demonstrated a high mercury capacity (1512ug/g) although in its current 3-mm pellet form only the outer layer is effectively utilized. The loading of 13% TiO2 shows the best removal, both with and without UV irradiation. Increasing TiO2 loading beyond this level does not enhance the removal further. It has also been observed that the composite after being 'activated' by photocatalytic oxidation has better performance, probably due to the change of surface functional groups. The examination of the effects of flow velocity reveals that mass transfer is the rate limiting step. Relative humidity has been found to impede adsorption therefore decreasing the overall removal efficiency. By rinsing with acid, both the deposited mercury and composite can be regenerated.

  10. Photocatalytic investigations of TiO2-P25 nanocomposite thin films prepared by peroxotitanic acid modified sol-gel method

    Science.gov (United States)

    Oshani, Fatemeh; Marandi, Reza; Rasouli, Sousan; Farhoud, Mitra Keramati

    2014-08-01

    TiO2 thin films and TiO2-P25 nanocomposite thin films were synthesized by sol-gel method utilizing peroxotitanic acid sol (PTA). Films were obtained by three dip coatings of sol on borosilicate glasses. The crystalline size and the variation in phase of thin films were determined through X-ray diffraction. The average crystalline size of the films that was in the range of 42 nm showed a reduction in the value by increasing the rutile content. The surface morphology of the films has been characterized utilizing Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Contact-mode atomic force microscopy (AFM). The results of the morphological investigations were completely coincided with the formation of TiO2-P25 nanocomposite. The optical property of the films has been evaluated by Diffuse Reflection Spectrophotometer (DRS) at the room temperature. The obtained UV-vis spectra for both TiO2 and TiO2-P25 thin films had similar maximum wavelengths. The band gap values for the direct and indirect transitions have been measured for the TiO2 and TiO2-P25 thin films and the results showed negligible variations. The photocatalytical activity of the films was studied by photodegradation of Reactive Red 222 (RR222) under UV irradiation. The results showed that the photocatalytic efficiency of TiO2-P25 nanocomposite thin films had enhanced by the addition of rutile phase which was obviously due to the cooperation of TiO2 and P25 nanoparticles in effective charge transfer process. Additionally, photodegradation rate constant result calculations for the TiO2-P25 nanocomposite thin films can well exhibit the increase in its photocatalytic performance in comparison with TiO2 thin films.

  11. Influence of the Porosity of the TiO2 Film on the Performance of the Perovskite Solar Cell

    Directory of Open Access Journals (Sweden)

    Xiaodan Sun

    2017-01-01

    Full Text Available The structure of mesoporous TiO2 (mp-TiO2 films is crucial to the performance of mesoporous perovskite solar cells (PSCs. In this study, we fabricated highly porous mp-TiO2 films by doping polystyrene (PS spheres in TiO2 paste. The composition of the perovskite films was effectively improved by modifying the mass fraction of the PS spheres in the TiO2 paste. Due to the high porosity of the mp-TiO2 film, PbI2 and CH3NH3I could sufficiently infiltrate into the network of the mp-TiO2 film, which ensured a more complete transformation to CH3NH3PbI3. The surface morphology of the mp-TiO2 film and the photoelectric performance of the perovskite solar cells were investigated. The results showed that an increase in the porosity of the mp-TiO2 film resulted in an improvement in the performance of the PSCs. The best device with the optimized mass fraction of 1.0 wt% PS in TiO2 paste exhibited an efficiency of 12.69%, which is 25% higher than the efficiency of the PSCs without PS spheres.

  12. 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.

  13. 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.

  14. The effect of light-scattering layer on the performance of dye-sensitized solar cell assembled using TiO2 double-layered films as photoanodes

    Science.gov (United States)

    Zhu, L.; Zhao, Y. L.; Lin, X. P.; Gu, X. Q.; Qiang, Y. H.

    2014-01-01

    Dye-sensitized solar cells (DSSCs) are fabricated based on double-layered films of TiO2 nanospheres and TiO2 nanorod arrays (NRAs). TiO2 nanospheres, including TiO2 hollow spheres (HSs) and TiO2 solid spheres (SSs), were served as light-scattering layers on TiO2 NRAs as composite photoanodes. The as-prepared TiO2 NRAs, TiO2 HSs and TiO2 SSs have been characterized by field emission scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The photoelectric properties of DSSCs were investigated by UV-vis reflectance spectra, current-voltage curves and electrochemical impedance spectroscopy. Owing to the synergic effects of the TiO2 HSs (SSs) and NRAs, including large specific surface area of HSs (SSs) as light-scattering layer for effective dye adsorption and harvesting light and rapid electron transport in one dimensional TiO2 NRAs, the optimal energy conversion efficiency of DSSCs with as-prepared double-layered films as nanocomposite photoanode (5.40%) were far higher than the ones using single-layered NRAs films (1.56%).

  15. Fabrication and Photocatalytic Property of One-Dimensional SrTiO3/TiO2-xNx Nanostructures

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    Huarong Zhang

    2013-01-01

    Full Text Available One-dimensional SrTiO3/TiO2−xNx nanostructures were prepared by the hydrothermal method and investigated by X-ray diffraction (XRD, transmission electron microscopy (TEM, X-ray photoelectron spectroscopy (XPS, and ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS measurements. The photocatalytic activities of the prepared samples were evaluated by photodegrading the methylene blue (MB solution. According to the characterizations, the intermediate product of SrTiO3/titanate nanotubes was presented after hydrothermal processing of the TiO2−xNx nanoparticles with the mixed solution of NaOH and Sr(NO32. The final product of SrTiO3/TiO2−xNx nanorods was obtained after calcining the intermediate. As compared to the TiO2−xNx nanoparticles, the absorption performance of SrTiO3/titanate nanotubes or SrTiO3/TiO2−xNx nanorods was depressed, instead of improving it. The mechanisms of the absorption property changes were discussed. The SrTiO3/TiO2−xNx nanorods presented better photocatalytic activity than the TiO2−xNx nanoparticles or nanorods. However, due to overmuch adsorption, the SrTiO3/titanate nanotubes gave ordinary photocatalytic performances.

  16. Influence of different TiO2 blocking films on the photovoltaic performance of perovskite solar cells

    Science.gov (United States)

    Zhang, Chenxi; Luo, Yudan; Chen, Xiaohong; Ou-Yang, Wei; Chen, Yiwei; Sun, Zhuo; Huang, Sumei

    2016-12-01

    Organolead trihalide perovskite materials have been successfully used as light absorbers in efficient photovoltaic (PV) cells. Cell structures based on mesoscopic metal oxides and planar heterojunctions have already demonstrated very impressive and brisk advances, holding great potential to grow into a mature PV technology. High power conversion efficiency (PCE) values have been obtained from the mesoscopic configuration in which a few hundred nano-meter thick mesoporous scaffold (e.g. TiO2 or Al2O3) infiltrated by perovskite absorber was sandwiched between the electron and hole transport layers. A uniform and compact hole-blocking layer is necessary for high efficient perovskite-based thin film solar cells. In this study, we investigated the characteristics of TiO2 compact layer using various methods and its effects on the PV performance of perovskite solar cells. TiO2 compact layer was prepared by a sol-gel method based on titanium isopropoxide and HCl, spin-coating of titanium diisopropoxide bis (acetylacetonate), screen-printing of Dyesol's bocking layer titania paste, and a chemical bath deposition (CBD) technique via hydrolysis of TiCl4, respectively. The morphological and micro-structural properties of the formed compact TiO2 layers were characterized by scanning electronic microscopy and X-ray diffraction. The analyses of devices performance characteristics showed that surface morphologies of TiO2 compact films played a critical role in affecting the efficiencies. The nanocrystalline TiO2 film deposited via the CBD route acts as the most efficient hole-blocking layer and achieves the best performance in perovskite solar cells. The CBD-based TiO2 compact and dense layer offers a small series resistance and a large recombination resistance inside the device, and makes it possible to achieve a high power conversion efficiency of 12.80%.

  17. Effect of Uniform Decoration of Ag2S Nanoparticles on Physical Properties of Granular TiO2 Thin Films Synthesized by Using Spin Coating Technique

    Directory of Open Access Journals (Sweden)

    R.A. Wagh

    2016-12-01

    Full Text Available In this work, we report the effect of uniform decoration of silver sulphide (Ag2S nanoparticles on physical properties of titanium dioxide (TiO2 nanocrystalline thin films synthesized by using a spin coating technique by preparing TiO2 gel using P-25 TiO2, ethanol, acetyl acetone and p-hydroxybenzoic acid. Chemical bath deposited layer of Ag2S particles enhance the properties of TiO2 nanocrystalline thin films. The optical study reveals that the absorption edge shifts towards the visible region compared with the pure TiO2 thin film due to the incorporation of Ag2S nanoparticles into TiO2 nanocrystalline thin films.

  18. The influence of concentration on the morphology of TiO2 thin films prepared by spray pyrolysis for electrochemical study

    Science.gov (United States)

    Fugare, B. Y.; Lokhande, B. J.

    2017-06-01

    In the nanoscale architecture, expected morphology plays an important role in the fabrication of supercapacitive devices due to their highly porous properties. Herein, a well-defined rutile TiO2 architecture was successfully prepared by spray pyrolysis technique (SPT), by changing the concentration of the spraying solution from 0.01 to 0.1 M at 723 K deposition temperature onto stainless steel substrates. The thermal decomposition behavior of the precursor is analyzed using thermogravimetric analyzer. As-deposited thin film electrodes exhibits rutile tetragonal crystalline structure confirmed using XRD. FT-IR study indicate the presence of Ti=O stretching vibration in the range 400-1000 cm-1. The obtained nanostructures merely changes by changing the concentration of spraying solution and process parameters as strongly evidenced using SEM. TEM image and SAED pattern confirms the formation of nanorods and rutile tetragonal structure of TiO2. EDAX confirms formation of pristine TiO2. Wettability of samples shows angle of contact changes by changing the sample thickness and surface roughness of the samples. Optimized electrode shows maximum specific capacitance 273.84 F/g at 2 mV/s in 1 M KOH. Maximum values of specific energy (SE), specific power (SP) and efficiency as observed using galvanostatic charge-discharge are 04.32 Wh/Kg, 70.27 KW/Kg and 90.37%, respectively.

  19. Effect of Pt Concentration on the Grain Growth of TiO2sol-gel Films

    Directory of Open Access Journals (Sweden)

    Jia Y.J.

    2017-01-01

    Full Text Available Pt metallic has been supported on TiO2 surface using different methods, Here, Pt doped TiO2 (Pt-TiO2 sol gel thin film were successfully produced by reducing chloroplatinc acid (H2PtCl6. The structures of prepared composites were investigated using X-ray diffraction (XRD. The physical morphologies of the composites were examined using transmission electron microscope (TEM. The grain size of Pt-TiO2 thin film after annealing was also measured by atomic force microscope (AFM images.

  20. Photo-induced degradation of Ru(Ⅱ) complex absorbed on anatase TiO2 thin film electrode

    Institute of Scientific and Technical Information of China (English)

    WANG DeLiang; WANG GuangLong; ZHAO JianHua; CHEN Bo

    2007-01-01

    Photo-induced degradation of a monolayer of Ru(II) complex absorbed on anatase TiO2 thin film was studied by using resonant micro-Raman spectroscopy. Under intense light radiation of a laser and in the absence of a reducing agent, the dye decomposed quickly. When the dye-sensitized TiO2 thin film electrode was covered by a reducing agent, namely the Ⅰ-/Ⅰ-3 redox couple, the photo-induced decomposing rate was slowed by a factor of ~106. In both cases, the dye decomposed with time under an exponential law.

  1. Fibrochondrocyte Growth and Functionality on TiO2 Nanothin Films

    Directory of Open Access Journals (Sweden)

    Sharon Ronald

    2016-06-01

    Full Text Available Disorders affecting the temporomandibular joint (TMJ are a long-standing health concern. TMJ disorders (TMJD are often associated with an internal disc derangement accompanied by a suite of symptoms including joint noises, jaw dysfunction, and severe pain. The severity of patient symptoms and their reoccurrence can be alleviated to some extent with conservative therapy; however, refractory cases often require surgery that has shown only limited success. Bioengineered scaffolds with cell supportive surfaces an d nanoarchitectures that mimic TMJ tissue structure may offer an alternative treatment modality. In this study, titanium dioxide (TiO2 nanothin films, fabricated by layer-by-layer assembly, were examined as means for creating such a scaffold. The viability and growth of TMJ discal fibrochondrocytes (FCs were assessed through MTT and DNA assays and total protein content over a 14-day experimental period. ELISA was also used to measure expression of types I and II collagen, decorin and aggrecan. Quantitative analyses demonstrated that FCs synthesized characteristic discal matrix proteins, with an increased production of type I collagen and decorin as opposed to collagen type II and aggrecan. A stimulatory effect on discal FC proliferation and extracellular matrix (ECM expression with thicker nanofilms was also observed. The cumulative results suggest that TiO2 nanofilms may have potential as a TMJ scaffolding material.

  2. Fibrochondrocyte Growth and Functionality on TiO2 Nanothin Films

    Science.gov (United States)

    Ronald, Sharon; Mills, David K.

    2016-01-01

    Disorders affecting the temporomandibular joint (TMJ) are a long-standing health concern. TMJ disorders (TMJD) are often associated with an internal disc derangement accompanied by a suite of symptoms including joint noises, jaw dysfunction, and severe pain. The severity of patient symptoms and their reoccurrence can be alleviated to some extent with conservative therapy; however, refractory cases often require surgery that has shown only limited success. Bioengineered scaffolds with cell supportive surfaces an d nanoarchitectures that mimic TMJ tissue structure may offer an alternative treatment modality. In this study, titanium dioxide (TiO2) nanothin films, fabricated by layer-by-layer assembly, were examined as means for creating such a scaffold. The viability and growth of TMJ discal fibrochondrocytes (FCs) were assessed through MTT and DNA assays and total protein content over a 14-day experimental period. ELISA was also used to measure expression of types I and II collagen, decorin and aggrecan. Quantitative analyses demonstrated that FCs synthesized characteristic discal matrix proteins, with an increased production of type I collagen and decorin as opposed to collagen type II and aggrecan. A stimulatory effect on discal FC proliferation and extracellular matrix (ECM) expression with thicker nanofilms was also observed. The cumulative results suggest that TiO2 nanofilms may have potential as a TMJ scaffolding material. PMID:27314395

  3. A Comparative Study of Nanostructured TiO2, ZnO and Bilayer TiO2/ZnO Dye-Sensitized Solar Cells

    Science.gov (United States)

    Rani, Mamta; Tripathi, S. K.

    2015-04-01

    Titanium dioxide (TiO2), Zinc oxide (ZnO) and bilayer TiO2/ZnO (TZO) based cells have been developed and sensitized with five organic dyes and one cocktail dye composed of five dyes. Photovoltaic performance of TiO2 and ZnO solar cell sensitized with six dyes is compared to that of bilayer TZO cells. The forward current is found to increase with applied voltage in the range V ≤ 0.4 V, which is dominated by thermionic emission, whereas in 0.4 ≤ V ≤ 0.7 V, the current transport is due to space charge-limited current controlled by exponential trap distribution in all devices. The combined properties of the materials enhance the efficiency of composite TZO cells. TiO2 permits the formation of an energy barrier at the ZnO electrode/electrolyte interface, which reduces the back electron transfer from the conduction band of ZnO to I3 - in the electrolyte. Also, due to the TiO2 layer on the ZnO, the latter forms a compact layer between flourine-doped tin oxide (FTO)/TiO2 which benefits the fast electron transfer from TiO2 to ZnO to FTO glass. This reduces the charge recombination occurring at the ZnO/FTO interface leading to higher open circuit voltage ( V oc), higher short circuit current ( J sc), lower series resistance ( R s), and in turn higher efficiency in TZO solar cells as compared to ZnO cells. Among the six dyes, Eosin-Y and Rose Bengal dye gave the best performance as sensitizers with TZO.

  4. Preparation and oxygen-sensing properties of TiO2 porous thin films on alumina substrate

    Institute of Scientific and Technical Information of China (English)

    LI Ming-li; XU Ming-xia; LI Yan

    2006-01-01

    The titanium dioxide sols were synthesized with tetrabutyl titanate as precursor,diethanolamine(DEA) as complexing agent ,polyethylene glycol (PEG) as organic template. The porous films were prepared by sol-gel method. The structures and morphology of the titanium dioxide porous films were characterized by FE-SEM. The formation mechanism of TiO2 porous films and the relation between the porous structure and oxygen-sensing properties of TiO2 films were studied. Ordered structure was formed by assembling between TiO2 colloid particles and the template molecules. PEG molecules acted on TiO2 colloid particles by hydrogen bond and bridge oxygen. The porous structure was formed after the organic template was decomposed when calcining the films. The diameter,amount and distribution of the pores in the films are related with the content of PEG.. The pore diameter increases with increasing of content of PEG and the pore density reaches the maximum at certain content. Oxygen-sensitivity and response speed of porous TiO2 films are improved compared with films without pores. Both the sensitivity and response speed increase with the increasing of pore diameter and pore density. Oxygen-sensitivity reaches 3 order of magnitude at 800 ℃. Its response time from H2/N2 to O2/N2 atmosphere and vice versa is about 0.11 s and 0.12 s respectively. Although the sensitivity and response speed increase,the resistance-temperature properties of porous films are not notably improved with the increasing of the content of PEG.

  5. Low-temperature Preparation of Photocatalytic TiO2 Thin Films on Polymer Substrates by Direct Deposition from Anatase Sol

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Anatase TiO2 sol was synthesized under mild conditions (75C and ambient pressure) by hydrolysis of titaniumn-butoxide in abundant acidic aqueous solution and subsequent reflux to enhance crystallization. At room temperature and in ambient atmosphere, crystalline TiO2 thin films were deposited on polymethylmethacrylate (PMMA), SiO2-coated PMMA and SiO2-coated silicone rubber substrates from the as-prepared TiO2 sol by a dip-coating process. SiO2 layers prior to TiO2 thin films on polymer substrates could not only protect the substrates from the photocatalytic decomposition of the TiO2 thin films but also enhance the adhesion of the TiO2 thin films to the substrates. Field-emission type scanning electron microscope (FE-SEM) investigations revealed that the average particle sizes of the nanoparticles composing the TiO2 thin films were about 35~47 nm. The TiO2 thin films exhibited high photocatalytic activities in the degradation of reactive brilliant red dye X-3B in aqueous solution under aerated conditions. The preparation process of photocatalytic TiO2 thin films on the polymer substrates was quite simple and a low temperature route.

  6. Design of a TiO2 nanosheet/nanoparticle gradient film photoanode and its improved performance for dye-sensitized solar cells.

    Science.gov (United States)

    Wang, Wenguang; Zhang, Haiyan; Wang, Rong; Feng, Ming; Chen, Yiming

    2014-02-21

    A TiO2 film photoanode with gradient structure in nanosheet/nanoparticle concentration on the fluorine-doped tin oxide glass from substrate to surface was prepared by a screen printing method. The as-prepared dye-sensitized solar cell (DSSC) based on the gradient film electrode exhibited an enhanced photoelectric conversion efficiency of 6.48%, exceeding that of a pure nanoparticle-based DSSC with the same film thickness by a factor of 2.6. The enhanced photovoltaic performance of the gradient film-based DSSC was attributed to the superior light scattering ability of TiO2 nanosheets within the gradient structure, which was beneficial to light harvesting. Furthermore, the TiO2 nanosheets with exposed {001} facets facilitated the electron transport from dye molecules to the conduction band of TiO2 and further to the conductive glass. Meanwhile, the high specific surface area of TiO2 nanosheets helped the adsorption of dye molecules, and the TiO2 nanoparticle underlayer ensured good electronic contact between the TiO2 film and the fluorine-doped tin oxide glass substrate. The electrochemical impedance spectroscopy measurements further confirmed the electron transport differences between DSSCs based on nanosheet/nanoparticle gradient film electrodes and DSSCs based on nanosheet/nanoparticle homogeneous mixtures, pure TiO2 nanoparticles and pure TiO2 nanosheets with the same film thickness.

  7. Effects of Co-addition of DBS and PEG on Wetting Performance of TiO2 Film

    Institute of Scientific and Technical Information of China (English)

    QU Yi-chun; JING Li-qiang; WANG Wen-xin; FU Hong-gang; LIU Yang

    2011-01-01

    Nanocrystalline anatase TiO2 films with indium tin oxide(ITO) coated glass as the film substrate were fabricated through spin-coating technique. The TiO2 pastes were prepared with sodium dodecylbenzenesulfonate(DBS)modified TiO2 nanocrystals, synthesized by sol-hydrothermal processes in advance, together with different amounts of polyethylene glycol(PEG) macromolecules. The as-prepared films were mainly characterized by ultraviolet-visible (UV-Vis) spectroscopy, field emission scanning electron microscopy(FE-SEM) and water contact angle(WCA) measurement. Effects of the addition of DBS and PEG on the wetting performance of the resulting films and relevant mechanisms were principally investigated. The results show that the as-prepared film displays super-hydrophilic property after co-addition of DBS and PEG although it is not exposed to ultraviolet light prior to the WCA measurement. This appealing result is mainly attributed to the produced micro- and nanometer-scale hierarchical surface structure with uniformly dispersed micro papillae. Each papilla was made up of a great number of TiO2 nanoparticles.The possible formation mechanisms related to the DBS amphiphilic property of the characteristic surface were also suggested. Moreover, the resulting film also exhibits considerable durability in the superhydrophilicity, which is very useful for practical application in self-cleaning, anti-fogging, and bacteria-resistant fields.

  8. Influence of Nd dopant amount on microstructure and photoluminescence of TiO2:Nd thin films

    Science.gov (United States)

    Wojcieszak, Damian; Mazur, Michal; Kaczmarek, Danuta; Morgiel, Jerzy; Zatryb, Grzegorz; Domaradzki, Jaroslaw; Misiewicz, Jan

    2015-10-01

    TiO2 and TiO2:Nd thin films were deposited using reactive magnetron sputtering process from mosaic Ti-Nd targets with various Nd concentration. The thin films were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM) and spectroscopic techniques. Photoluminescence (PL) in the near infrared obtained upon 514.5 nm excitation was also examined. The relationship between the Nd concentration, structural, optical and photoluminescence properties of prepared thin films was investigated and discussed. XRD and TEM measurements showed that an increase in the Nd concentration in the thin films hinders the crystal growth in the deposited coatings. Depending on the Nd amount in the thin films, TiO2 with the rutile, mixed rutile-amorphous or amorphous phase was obtained. Transmittance measurements revealed that addition of Nd dopant to titania matrix did not deteriorate optical transparency of the coatings, however it influenced on the position of the fundamental absorption edge and therefore on the width of optical band gap energy. All TiO2:Nd thin films exhibited PL emission that occurred at ca. 0.91, 1.09 and 1.38 μm. Finally, results obtained for deposited coatings showed that titania with the rutile structure and 1.0 at.% of Nd was the most efficient in VIS to NIR photon conversion.

  9. Nano-tribological characteristics of TiO2 films on 3-mercaptopropyl trimethoxysilane sulfonated self-assembled monolayer

    Indian Academy of Sciences (India)

    J Li; X H Sheng

    2009-10-01

    Silane coupling reagent (3-mercaptopropyl trimethoxysilane (MPTS)) was used to prepare twodimensional self-assembled monolayer (SAM) on silicon substrate. The terminal –SH group was in situ oxidized to –SO3H group to endow the film with good chemisorption ability. Then TiO2 thin films were deposited on the oxidized MPTS–SAM to form composite thin films, making use of the chemisorption ability of the –SO3H group. Atomic force microscope (AFM) and contact angle measurements were used to characterize TiO2 films. Adhesive force and friction force of TiO2 thin films and silicon substrate were measured under various applied normal loads and scanning speed of AFM tip. Results showed that the friction force increased with applied normal loads and scanning speed of AFM tip. In order to study the effect of capillary force, tests were performed in various relative humidities. Results showed that the adhesive force of silicon substrate increases with relative humidities and the adhesive force of TiO2 thin films only increases slightly with relative humidity. Research showed that surfaces with more hydrophobic property revealed the lower adhesive and friction forces.

  10. Resonant infrared matrix-assisted pulsed laser evaporation of TiO2 nanoparticle films

    Science.gov (United States)

    Mayo, Daniel C.; Paul, Omari; Airuoyo, Idemudia J.; Pan, Zhengda; Schriver, Kenneth E.; Avanesyan, Sergey M.; Park, Hee K.; Mu, Richard R.; Haglund, Richard F.

    2013-03-01

    The successful development of flexible, high performance thin films that are competitive with silicon-based technology will likely require fabricating films of hybrid materials that incorporate nanomaterials, glasses, ceramics, polymers, and thin films. Resonant infrared matrix-assisted pulsed laser evaporation (RIR-MAPLE) is an ideal method for depositing organic materials and nanoparticles with minimal photochemical or photothermal damage to the deposited material. Furthermore, there are many nonhazardous solvents containing chemical functional groups with infrared absorption bands that are accessible using IR lasers. We report here results of recent work in which RIR-MAPLE has been employed successfully to deposit thin films of TiO2 nanoparticles on Si substrates. Using an Er:YAG laser ( λ=2.94 μm), we investigated a variety of MAPLE matrices containing -OH moieties, including water and all four isomers of butyl alcohol. The alcohol isomers are shown to provide effective and relatively nontoxic solvents for use in the RIR-MAPLE process. In addition, we examine the effects of varying concentration and laser fluence on film roughness and surface coverage.

  11. Improved electron transfer and plasmonic effect in dye-sensitized solar cells with bi-functional Nb-doped TiO2/Ag ternary nanostructures.

    Science.gov (United States)

    Park, Jung Tae; Chi, Won Seok; Jeon, Harim; Kim, Jong Hak

    2014-03-07

    TiO2 nanoparticles are surface-modified via atom transfer radical polymerization (ATRP) with a hydrophilic poly(oxyethylene)methacrylate (POEM), which can coordinate to the Ag precursor, i.e. silver trifluoromethanesulfonate (AgCF3SO3). Following the reduction of Ag ions, a Nb2O5 doping process and calcination at 450 °C, bi-functional Nb-doped TiO2/Ag ternary nanostructures are generated. The resulting nanostructures are characterized by energy-filtering transmission electron microscopy (EF-TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV-visible spectroscopy. The dye-sensitized solar cell (DSSC) based on the Nb-doped TiO2/Ag nanostructure photoanode with a polymerized ionic liquid (PIL) as the solid polymer electrolyte shows an overall energy conversion efficiency (η) of 6.9%, which is much higher than those of neat TiO2 (4.7%) and Nb-doped TiO2 (5.4%). The enhancement of η is mostly due to the increase of current density, attributed to the improved electron transfer properties including electron injection, collection, and plasmonic effects without the negative effects of charge recombination or problems with corrosion. These properties are supported by intensity modulated photocurrent/voltage spectroscopy (IMPS/IMVS) and incident photon-to-electron conversion efficiency (IPCE) measurements.

  12. Effect of nanostructured TiO2 crystal phase on photoinduced apoptosis of breast cancer epithelial cells

    Directory of Open Access Journals (Sweden)

    Lagopati N

    2014-07-01

    Full Text Available Nefeli Lagopati,1,2 Effie-Photini Tsilibary,1,* Polycarpos Falaras,2,* Panagiota Papazafiri,3 Evangelia A Pavlatou,4 Eleni Kotsopoulou,1 Paraskevi Kitsiou1,* 1Institute of Biosciences and Applications, 2Institute of Advanced Materials, Physicochemical Processes, Nanotechnology and Microsystems, National Center for Scientific Research “Demokritos”, Athens, Greece; 3Department of Animal and Human Physiology, Faculty of Biology, School of Science, National and Kapodistrian University of Athens, Athens, Greece; 4Laboratory of General Chemistry, School of Chemical Engineering, National Technical University of Athens, Athens, Greece *These authors contributed equally to this work Purpose: The use of nanoparticles has seen exponential growth in the area of health care, due to the unique physicochemical properties of nanomaterials that make them desirable for medical applications. The aim of this study was to examine the effects of crystal phase-nanostructured titanium dioxide particles on bioactivity/cytotoxicity in breast cancer epithelial cells. Materials and methods: Cultured Michigan Cancer Foundation (MCF-7 and human breast adenocarcinoma (MDA-MB-468 breast cancer epithelial cells were exposed to ultraviolet A light (wavelength 350 nm for 20 minutes in the presence of aqueous dispersions of two different nanostructured titanium dioxide (TiO2 crystal phases: anatase and an anatase–rutile mixture. Detailed characterization of each titanium dispersion was performed by dynamic light scattering. A 3-(4,5-dimethylthiazol-2-yl-2,5 diphenyltetrazolium bromide (MTT colorimetric assay was employed to estimate the percentage of viable cells after each treatment. Western blot analysis of protein expression and characterization, as well as a deoxyribonucleic acid (DNA-laddering assay, were used to detect cell apoptosis. Results: Our results documented that 100% anatase TiO2 nanoparticles (110–130 nm exhibited significantly higher cytotoxicity in

  13. Schottky junction/ohmic contact behavior of a nanoporous TiO(2) thin film photoanode in contact with redox electrolyte solutions.

    Science.gov (United States)

    Kaneko, Masao; Ueno, Hirohito; Nemoto, Junichi

    2011-01-01

    The nature and photoelectrochemical reactivity of nanoporous semiconductor electrodes have attracted a great deal of attention. Nanostructured materials have promising capabilities applicable for the construction of various photonic and electronic devices. In this paper, a mesoporous TiO(2) thin film photoanode was soaked in an aqueous methanol solution using an O(2)-reducing Pt-based cathode in contact with atmospheric air on the back side. It was shown from distinct photocurrents in the cyclic voltammogram (CV) that the nanosurface of the mesoporous n-TiO(2) film forms a Schottky junction with water containing a strong electron donor such as methanol. Formation of a Schottky junction (liquid junction) was also proved by Mott-Schottky plots at the mesoporous TiO(2) thin film photoanode, and the thickness of the space charge layer was estimated to be very thin, i.e., only 3.1 nm at -0.1 V vs Ag/AgCl. On the other hand, the presence of [Fe(CN)(6)](4-) and the absence of methanol brought about ohmic contact behavior on the TiO(2) film and exhibited reversible redox waves in the dark due to the [Fe(CN)(6)](4-/3-) couple. Further studies showed that multiple Schottky junctions/ohmic contact behavior inducing simultaneously both photocurrent and overlapped reversible redox waves was found in the CV of a nanoporous TiO(2) photoanode soaked in an aqueous redox electrolyte solution containing methanol and [Fe(CN)(6)](4-). That is, the TiO(2) nanosurface responds to [Fe(CN)(6)](4-) to give ohmic redox waves overlapped simultaneously with photocurrents due to the Schottky junction. Additionally, a second step photocurrent generation was observed in the presence of both MeOH and [Fe(CN)(6)](4-) around the redox potential of the iron complex. It was suggested that the iron complex forms a second Schottky junction for which the flat band potential (E(fb)) lies near the redox potential of the iron complex.

  14. Schottky junction/ohmic contact behavior of a nanoporous TiO2 thin film photoanode in contact with redox electrolyte solutions

    Directory of Open Access Journals (Sweden)

    Masao Kaneko

    2011-02-01

    Full Text Available The nature and photoelectrochemical reactivity of nanoporous semiconductor electrodes have attracted a great deal of attention. Nanostructured materials have promising capabilities applicable for the construction of various photonic and electronic devices. In this paper, a mesoporous TiO2 thin film photoanode was soaked in an aqueous methanol solution using an O2-reducing Pt-based cathode in contact with atmospheric air on the back side. It was shown from distinct photocurrents in the cyclic voltammogram (CV that the nanosurface of the mesoporous n-TiO2 film forms a Schottky junction with water containing a strong electron donor such as methanol. Formation of a Schottky junction (liquid junction was also proved by Mott–Schottky plots at the mesoporous TiO2 thin film photoanode, and the thickness of the space charge layer was estimated to be very thin, i.e., only 3.1 nm at −0.1 V vs Ag/AgCl. On the other hand, the presence of [Fe(CN6]4− and the absence of methanol brought about ohmic contact behavior on the TiO2 film and exhibited reversible redox waves in the dark due to the [Fe(CN6]4−/3− couple. Further studies showed that multiple Schottky junctions/ohmic contact behavior inducing simultaneously both photocurrent and overlapped reversible redox waves was found in the CV of a nanoporous TiO2 photoanode soaked in an aqueous redox electrolyte solution containing methanol and [Fe(CN6]4−. That is, the TiO2 nanosurface responds to [Fe(CN6]4− to give ohmic redox waves overlapped simultaneously with photocurrents due to the Schottky junction. Additionally, a second step photocurrent generation was observed in the presence of both MeOH and [Fe(CN6]4− around the redox potential of the iron complex. It was suggested that the iron complex forms a second Schottky junction for which the flat band potential (Efb lies near the redox potential of the iron complex.

  15. Illumination intensity dependence of the photovoltage in nanostructured TiO2 dye-sensitized solar cells.

    Science.gov (United States)

    Salvador, P; Hidalgo, M Gonzalez; Zaban, Arie; Bisquert, Juan

    2005-08-25

    The open-circuit voltage (V(oc)) dependence on the illumination intensity (phi0) under steady-state conditions in both bare and coated (blocked) nanostructured TiO2 dye-sensitized solar cells (DSSCs) is analyzed. This analysis is based on a recently reported model [Bisquert, J.; Zaban, A.; Salvador, P. J. Phys. Chem. B 2002, 106, 8774] which describes the rate of interfacial electron transfer from the conduction band of TiO2 to acceptor electrolyte levels (recombination). The model involves two possible mechanisms: (1) direct, isoenergetic electron injection from the conduction band and (2) a two-step process involving inelastic electron trapping by band-gap surface states and subsequent isoenergetic transfer of trapped electrons to electrolyte levels. By considering the variation of V(oc) over a wide range of illumination intensities (10(10) DSSC is analyzed. It is concluded that this back-reaction route can be neglected, even at low light intensities, when its rate (exchange current density, j0), which can vary over 4 orders of magnitude depending on the type of FTO used, is low enough (j0 < or = 10(-8)A cm(-2)). The comparison of V(oc) vs phi0 measurements corresponding to different DSSCs with and without blocking of the FTO-electrolyte contact supports this conclusion.

  16. Influence of Pore Size on the Optical and Electrical Properties of Screen Printed TiO2 Thin Films

    Directory of Open Access Journals (Sweden)

    Dinfa Luka Domtau

    2016-01-01

    Full Text Available Influence of pore size on the optical and electrical properties of TiO2 thin films was studied. TiO2 thin films with different weight percentages (wt% of carbon black were deposited by screen printing method on fluorine doped tin oxide (FTO coated on glass substrate. Carbon black decomposed on annealing and artificial pores were created in the films. All the films were 3.2 µm thick as measured by a surface profiler. UV-VIS-NIR spectrophotometer was used to study transmittance and reflectance spectra of the films in the photon wavelength of 300–900 nm while absorbance was studied in the range of 350–900 nm. Band gaps and refractive index of the films were studied using the spectra. Reflectance, absorbance, and refractive index were found to increase with concentrations of carbon black. There was no significant variation in band gaps of films with change in carbon black concentrations. Transmittance reduced as the concentration of carbon black in TiO2 increased (i.e., increase in pore size. Currents and voltages (I-V characteristics of the films were measured by a 4-point probe. Resistivity (ρ and conductivity (σ of the films were computed from the I-V values. It was observed that resistivity increased with carbon black concentrations while conductivity decreased as the pore size of the films increased.

  17. 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.

  18. Growth and structure of MBE grown TiO2 anatase films with rutile nano-crystallites

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Rui; Wang, Chong M.; McCready, David E.; Droubay, Timothy C.; Chambers, Scott A.

    2007-03-15

    We have grown TiO2 anatase films with rutile nanocrystalline inclusions using molecular beam epitaxy under different growth conditions. This model system is important for investigating the role of rutile/anatase interfaces in heterogeneous photocatalysis. To control the film structure, we grew a pure anatase (001) layer at a slow rate and then increased the growth rate to drive the nucleation of rutile particles. Structure analysis indicates that the rutile phase has four preferred orientations in the anatase film.

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

    Science.gov (United States)

    Ghrairi, Najla; Bouaicha, Mongi

    2012-07-01

    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 μA, where the surface of the formed cell is 3.14 cm2.

  20. Characterization and photocatalytic activity of boron-doped TiO2 thin films prepared by liquid phase deposition technique

    Indian Academy of Sciences (India)

    Noor Shahina Begum; H M Farveez Ahmed; O M Hussain

    2008-10-01

    Boron doped TiO2 thin films have been successfully deposited on glass substrate and silicon wafer at 30°C from an aqueous solution of ammonium hexa-fluoro titanate and boron trifluoride by liquid phase deposition technique. The boric acid was used as an – scavenger. The resultant films were characterized by XRD, EDAX, UV and microstructures by SEM. The result shows the deposited film to be amorphous which becomes crystalline between 400 and 500°C. The EDAX and XRD data confirm the existence of boron atom in TiO2 matrix and a small peak corresponding to rutile phase was also found. Boron doped TiO2 thin films can be used as photocatalyst for the photodegradation of chlorobenzene which is a great environmental hazard. It was found that chlorobenzene undergoes degradation efficiently in presence of boron doped TiO2 thin films by exposing its aqueous solution to visible light. The photocatalytic activity increases with increase in the concentration of boron.

  1. Structural and photocatalytic properties of TiO2 films fabricated on silicon substrates by MOCVD method

    Institute of Scientific and Technical Information of China (English)

    YANG Jia-long; LI Ying; WANG Fu; ZUO Liang; Gu-Chul Yi; Wong Yong Choi

    2005-01-01

    Silicon(111) and Silicon(100) were employed for fabrication of TiO2 films by metal organic chemical vapor deposition(MOCVD).Titanium(Ⅳ) isopropoxide(Ti[O(C3H7)4]) was used as a precursor. The as-deposited TiO2 films were characterized with FE-SEM, XRD and AFM. The photocatalytic properties were investigated by decomposition of aqueous Orange Ⅱ. And UV-VIS photospectrometer was used for checking the absorption characteristics and photocatalytic degradation activity. The crystalline and structural properties of TiO2 film had crucial influences on the photodegradation efficiency. For MOCVD in-situ deposited films on Si substrates, the photoactivities varied following a shape of "M": at lower(350℃), middle(500℃) and higher(800℃) temperature of deposition, relative lower photodegradation activities were observed. At 400℃ and 700℃ of deposition, relative higher efficiencies of degradation were obtained, because one predominant crystallite orientation could be obtained as deposition at the temperature of two levels, especially a single anatase crystalline TiO2 film could be obtained at 700℃.

  2. Dopamine sensitized nanoporous TiO2 film on electrodes: photoelectrochemical sensing of NADH under visible irradiation.

    Science.gov (United States)

    Wang, Guang-Li; Xu, Jing-Juan; Chen, Hong-Yuan

    2009-04-15

    Dopamine-coordinated photoactive TiO(2) nanoporous films with a wide excitation range of light in the visible region (up to 580 nm) were prepared and used for sensitive detection of NADH. Colloidal TiO(2) was firstly covered on an indium-tin oxide (ITO) electrode surface and sintered at 450 degrees C to form a nanoporous TiO(2) film, then the electrode was dipped in a dopamine solution to form a dopamine-TiO(2) charge transfer complex via coordinating dopamine with undercoordinated titanium atoms on the electrode surface. This charge transfer complex provided an anodic photocurrent under visible light and the photocurrent could be largely enhanced by NADH. The photocurrent enhancement might be due to the electron transfer between NADH and the holes localized on dopamine. A new photoelectrochemical methodology for sensitive detection of NADH at a relatively low potential was developed. The detection limit of NADH was 1.4x10(-7) M, and the detection range could extend up to 1.2x10(-4) M. The dopamine-TiO(2) modified electrode exhibits its major advantages such as effective electronic transducer, fast response and easy fabrication for photoelectrochemical determination of NADH. This strategy largely reduces the destructive effect of UV light and the photogenerated holes of illuminated TiO(2) to biomolecules and opens a new avenue for the applications of TiO(2) in photoelectrochemical biosensing.

  3. Degradation of Typical Indoor Air Pollutants Using Fe-Doped TiO2 Thin Film under Daylight Illumination

    Directory of Open Access Journals (Sweden)

    Shuaijie Wang

    2014-01-01

    Full Text Available A type of iron-doped titania thin film was prepared by means of sol-gel method to degrade indoor formaldehyde (HCHO, ammonia (NH3, and benzene (C6H6 under sunlight. The photocatalysts were characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM, UV-Vis spectroscopy, and energy dispersive spetra (EDS. The results showed that the iron was doped in the TiO2 photocatalyst successfully. The absorption edge of doped TiO2 had red shifts and the doped TiO2 had a stronger absorption than the pure TiO2 in the visible region. Fe-doped TiO2 thin film prepared with the optimal preparation condition could remove indoor HCHO, NH3 and C6H6 effectively under solar light irradiation. The removal percentage of HCHO, NH3 or C6H6 after 9 h photocatalytic reaction under solar light reached 55%, 53.1%, and 37.5%, respectively, when they existed in the air individually. When the three pollutants were mixed in the air, the removal percentage decreased to 33.3%, 28.3%, and 28%. The degradation reaction of the three pollutants followed the pseudo first-order kinetics, which reflects that the photocatalytic reaction was controlled by the surface chemical reaction and the reaction rate was controlled by concentration of reactants.

  4. Preparations of TiO2 film coated on foam nickel substrate by sol-gel processes and its photocatalytic activity for degradation of acetaldehyde

    Institute of Scientific and Technical Information of China (English)

    HU Hai; XIAO Wen-jun; YUAN Jian; SHI Jian-wei; CHEN Ming-xia; SHANG GUAN Wen-feng

    2007-01-01

    Anatase TiO2 films were successfully prepared on foam nickel substrates by sol-gel technique using tetrabutyl titanate as precursor. The characteristics of the TiO2 films were investigated by XPS, XRD, FE-SEM, TEM and UV-Vis absorption spectra. The photocatalytic activities of TiO2 films were investigated by photocatalytic degradation reactions of gaseous acetaldehyde, an indoor pollutant, under ultraviolet light irradiation. It was found that Ni2+ doping into TiO2 films due to the foam nickel substrates resulted in the extension of absorption edges of TiO2 films from UV region to visible light region. The pre-heating for foam nickel substrates resulted in the formation of NiO layer, which prevented effectively the injection of photogenerated electrons from TiO2 films to metal nickel. The TiO2 films displayed high photocatalytic activity for the degradation of acetaldehyde, and were enhanced by calcining the substrates and coating TiO2 films repeatedly. The high activity was mainly attributed to the improvement of the characteristics of substrate surface and the increase of active sites on photocatalyst.

  5. Tuning the optical bandgap of TiO2-TiN composite films as photocatalyst in the visible light

    Directory of Open Access Journals (Sweden)

    Zheng Xie

    2013-06-01

    Full Text Available TiO2-TiN composite catalysts were prepared by oxidizing the TiN films in air at 350 °C. By adjusting the oxidation time to control the oxidation stage of TiN films, the optical band gap of the TiO2-TiN composites can be varied in a wide range from 1.68 eV to 3.23 eV. These composite films all showed red shift in photo-response towards the visible region, and depending on the optical band gap, some composite films exhibited good catalytic activity in the visible light region. This study provides a simple but effective method to prepare film photocatalyst working in visible light.

  6. Fabrication of SnO2-TiO2 core-shell nanopillar-array films for enhanced photocatalytic activity

    Science.gov (United States)

    Cheng, Hsyi-En; Lin, Chun-Yuan; Hsu, Ching-Ming

    2017-02-01

    Immobilized or deposited thin film TiO2 photocatalysts are suffering from a low photocatalytic activity due to either a low photon absorption efficiency or a high carrier recombination rate. Here we demonstrate that the photocatalytic activity of TiO2 can be effectively improved by the SnO2-TiO2 core-shell nanopillar-array structure which combines the benefits of SnO2/TiO2 heterojunction and high reaction surface area. The SnO2-TiO2 core-shell nanopillar-array films were fabricated using atomic layer deposition and dry etching techniques via barrier-free porous anodic alumina templates. The photocatalytic activity of the prepared films was evaluated by methylene blue (MB) bleaching under 352 nm UV light irradiation. The results show that the photocatalytic activity of TiO2 film was 45% improved by introducing a SnO2 film between TiO2 and ITO glass substrate and was 300% improved by using the SnO2-TiO2 core-shell nanopillar-array structure. The 45% improvement by the SnO2 interlayer is attributed to the SnO2/TiO2 heterojunction which separates the photogenerated electron-hole pairs in TiO2 for MB degradation, and the high photocatalytic activity of the SnO2-TiO2 core-shell nanopillar-array films is attributed to the three dimensional SnO2/TiO2 heterojunction which owns both the carrier separation ability and the high photocatalytic reaction surface area.

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

    Science.gov (United States)

    Panda, A. B.; Mahapatra, S. K.; Barhai, P. K.; Das, A. K.; Banerjee, I.

    2012-10-01

    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 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.

  8. Modification of the morphology of P(S-b-EO) templated thin TiO2 films by swelling with PS homopolymer.

    Science.gov (United States)

    Perlich, J; Schulz, L; Abul Kashem, M M; Cheng, Y-J; Memesa, M; Gutmann, J S; Roth, S V; Müller-Buschbaum, P

    2007-09-25

    For the controlled modification of sol-gel-templated polymer nanocomposites, which are transferred to a nanostructured, crystalline TiO2 phase by a calcination process, the addition of a single homopolymer was investigated. For the preparation, the homopolymer polystyrene (PS) is added in different amounts to the diblock copolymer P(S-b-EO) acting as a templating agent. The homopolymer/diblock copolymer blend system is combined with sol-gel chemistry to provide and attach the TiO2 nanoparticles to the diblock copolymer. So-called good-poor solvent-pair-induced phase separation leads to the formation of nanostructures by film preparation via spin coating. The fabricated morphologies are studied as a function of added homopolymer before and after calcination with atomic force microscopy, field emission scanning electron microscopy, and grazing incidence small-angle X-ray scattering. The observed behavior is discussed in the framework of controlling the block copolymer morphologies by the addition of homopolymers. At small homopolymer concentrations, the increase in homopolymer concentration changes the structure size, whereas at high homopolymer concentrations, a change in morphology is triggered. Thus, the behavior of a pure polymer system is transferred to a more complex hybrid system.

  9. Hierarchical nanostructures of copper(II) phthalocyanine on electrospun TiO(2) nanofibers: controllable solvothermal-fabrication and enhanced visible photocatalytic properties.

    Science.gov (United States)

    Zhang, Mingyi; Shao, Changlu; Guo, Zengcai; Zhang, Zhenyi; Mu, Jingbo; Cao, Tieping; Liu, Yichun

    2011-02-01

    In the present work, 2,9,16,23-tetranitrophthalocyanine copper(II) (TNCuPc)/TiO(2) hierarchical nanostructures were successfully fabricated by a simple combination method of electrospinning technique and solvothermal processing. Scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, X-ray diffraction (XRD), UV-vis diffuse reflectance (DR), Fourier transform infrared spectrum (FT-IR), X-ray photoelectron spectroscopy (XPS), and thermal gravimetric and differential thermal analysis (TG-DTA) were used to characterize the as-synthesized TNCuPc/TiO(2) hierarchical nanostructures. The results showed that the secondary TNCuPc nanostructures were not only successfully grown on the primary TiO(2) nanofibers substrates but also uniformly distributed without aggregation. By adjusting the solvothermal fabrication parameters, the TNCuPc nanowires or nanoflowers were facilely fabricated, and also the loading amounts of TNCuPc could be controlled on the TNCuPc/TiO(2) hierarchical nanostructural nanofibers. And, there might exist the interaction between TNCuPc and TiO(2). A possible mechanism for the formation of TNCuPc/TiO(2) hierarchical nanostructures was suggested. The photocatalytic studies revealed that the TNCuPc/TiO(2) hierarchical nanostructures exhibited enhanced photocatalytic efficiency of photodegradation of Rhodamine B (RB) compared with the pure TNCuPc or TiO(2) nanofibers under visible-light irradiation.

  10. Spin Speed and Duration Dependence of TiO2 Thin Films pH Sensing Behavior

    Directory of Open Access Journals (Sweden)

    Muhammad AlHadi Zulkefle

    2016-01-01

    Full Text Available Titanium dioxide (TiO2 thin films were applied as the sensing membrane of an extended-gate field-effect transistor (EGFET pH sensor. TiO2 thin films were deposited by spin coating method and the influences of the spin speed and spin duration on the pH sensing behavior of TiO2 thin films were investigated. The spin coated TiO2 thin films were connected to commercial metal-oxide-semiconductor field-effect transistor (MOSFET to form the extended gates and the MOSFET was integrated in a readout interfacing circuit to complete the EGFET pH sensor system. For the spin speed parameter investigation, the highest sensitivity was obtained for the sample spun at 3000 rpm at a fixed spinning time of 60 s, which was 60.3 mV/pH. The sensitivity was further improved to achieve 68 mV/pH with good linearity of 0.9943 when the spin time was 75 s at the speed of 3000 rpm.

  11. Characterization of Ni-doped TiO2 thin films deposited by dip-coating technique

    Science.gov (United States)

    Kharoubi, Abdelmalek; Bouaza, A.; Benrabah, B.; Ammari, A.; Khiali, A.

    2015-12-01

    Undoped and Ni-doped TiO2 thin films have been prepared by sol-gel dip-coating method on glass and silicon substrates. X-ray diffraction studies show that both TiO2 and Ni-doped TiO2 thin films are of anatase phase with (1 0 1) as preferential orientation. From the UV-visible spectroscopy analysis, all films exhibits a high transparency ~ 80% and shows that the optical band gap decreases from 3.66 to 3.59 eV, which may be related with the phase composition and impurities. Fourier transformed infrared spectroscopy (FTIR) study confirms the presence of Ti-O, Ti=O and O-H bands. Thermal analysis by differential scanning calorimetriy (DSC) shows endothermic reactions between 30 °C and 280 °C and exothermic reactions between 370 °C and 540 °C corresponding to the crystallization of TiO2 in the anatase phase. The Nyquist plots suggests that the equivalent circuit of the films is an RpCp parallel circuit and shows an increase in resistance Rp with increasing the Ni concentration and a decrease in capacity Cp.

  12. TiO2:(Fe, S Thin Films Prepared from Complex Precursors by CVD, Physical Chemical Properties, and Photocatalysis

    Directory of Open Access Journals (Sweden)

    V. G. Bessergenev

    2012-01-01

    Full Text Available The TiO2 thin films were prepared using Ti(dpm2(OPri2 and Ti(OPri4 (dpm = 2,2,6,6-tetramethylheptane-3,5-dione, Pri = isopropyl as the precursors. The volatile compounds Fe[(C2H52NCS2]3 and [(CH3C]2S2 were used to prepare doped TiO2 films. The synthesis was done in vacuum or in the presence of Ar and O2. The pressure in the CVD chamber was varied between 1.2×10−4 mbar and 0.1 mbar, with the system working either in the molecular beam or gas flow regime. Physical, chemical, and photocatalytic properties of the (Fe, S-doped TiO2 films were studied. Those TiO2:(Fe, S films prepared from the Ti(OPri4 precursor show increased photocatalytic activities, very close to those of Degussa P25 powder in UV region.

  13. Substrate Biasing during Plasma-Assisted ALD for Crystalline Phase-Control of TiO(2) Thin Films

    NARCIS (Netherlands)

    Profijt, H. B.; M. C. M. van de Sanden,; Kessels, W. M. M.

    2012-01-01

    Substrate biasing has been implemented in a remote plasma atomic layer deposition (ALD) reactor, enabling control of the ion energy up to 260 eV. For TiO(2) films deposited from Ti(Cp(Me))(NMe(2))(3) and O(2) plasma it is demonstrated that the crystalline phase can be tailored by tuning the ion ener

  14. TiO2 nanotube formation by Ti film anodization and their transport properties for dye-sensitized solar cells

    NARCIS (Netherlands)

    Iraj, M.; Kolahdouz, M.; Asl-Soleimani, E.; Esmaeili, E.; Kolahdouz Esfahani, Z.

    2016-01-01

    In this paper, we present the synthesis of TiO2 nanotube (NT) arrays formed by anodization of Ti film deposited on a fluorine-doped tin oxide-coated glass substrate by direct current magnetron sputtering. NH4F/ethylene glycol electrolyte was used to demonstrate the growth of stable nanotubes at room

  15. Surface constructions of nano TiO_2 as the environmental and energy materials

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    TiO_2 has attracted an increasing attention because of its variety of potential applications in environments and energies,such as gas sensing,self-cleaning,solar energy conversion, wettability and photo-catalysis applications.In this presentation,we summarize some progress in surface constructions of nano TiO_2 and its characterizations of physicochemistry and properties. (1)Superhydrophobic nanostructure TiO_2 films Superhydrophobic nanotube,nanopore and sponge-like structure TiO_2 films are fabricated ...

  16. Direct observation of photoinduced charge redistribution of WO3-TiO2 double layer nanocomposite films by photoassisted Kelvin force microscopy

    Science.gov (United States)

    Wang, S. J.; Cheng, G.; Jiang, X. H.; Li, Y. C.; Huang, Y. B.; Du, Z. L.

    2006-05-01

    The microscopic photoinduced charge redistribution between heterogeneous semiconductor nanofilms of WO3 and TiO2 double layers (written as WO3-TiO2 nanocomposite films) was directly observed using Kelvin probe force microscopy (KFM) coupled with an UV light source. Under illumination the surface potential morphologies of WO3-TiO2 nanocomposite films changed from 162to592mV, which was associated with the photoinduced charge transfer between WO3 and TiO2 nanoparticles due to the energy level alignment between them. This improved technique of photoassisted KFM was presented to visualize the photoinduced charge transfer between different semiconductor nanoparticles on microscopic scale.

  17. Effect of annealing temperature on wettability of TiO2 nanotube array films

    Science.gov (United States)

    2014-01-01

    Highly ordered TiO2 nanotube array (TN) films were prepared by anodization of titanium foil in a mixed electrolyte solution of glycerin and NH4F and then annealed at 200°C, 400°C, 600°C, and 800°C, respectively. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), water contact angle (WCA), and photoluminescence (PL). It was found that low temperature (below 600°C) has no significant influence on surface morphology, but the diameter of the nanotube increases from 40 to 50 nm with increasing temperature. At 800°C, the nanotube arrays are completely destroyed and only dense rutile film is observed. Samples unannealed and annealed at 200°C are amorphous. At 400°C, anatase phase appears. At 600°C, rutile phase appears. At 800°C, anatase phase changes into rutile phase completely. The wettability of the TN films shows that the WCAs for all samples freshly annealed at different temperatures are about 0°. After the annealed samples have been stored in air for 1 month, the WCAs increase to 130°, 133°, 135°, 141°, and 77°, respectively. Upon ultraviolet (UV) irradiation, they exhibit a significant transition from hydrophobicity to hydrophilicity. Especially, samples unannealed and annealed at 400°C show high photoinduced hydrophilicity. PMID:25426006

  18. Structure and photoluminescence of the TiO2 films grown by atomic layer deposition using tetrakis-dimethylamino titanium and ozone.

    Science.gov (United States)

    Jin, Chunyan; Liu, Ben; Lei, Zhongxiang; Sun, Jiaming

    2015-01-01

    TiO2 films were grown on silicon substrates by atomic layer deposition (ALD) using tetrakis-dimethylamino titanium and ozone. Amorphous TiO2 film was deposited at a low substrate temperature of 165°C, and anatase TiO2 film was grown at 250°C. The amorphous TiO2 film crystallizes to anatase TiO2 phase with annealing temperature ranged from 300°C to 1,100°C in N2 atmosphere, while the anatase TiO2 film transforms into rutile phase at a temperature of 1,000°C. Photoluminescence from anatase TiO2 films contains a red band at 600 nm and a green band at around 515 nm. The red band exhibits a strong correlation with defects of the under-coordinated Ti(3+) ions, and the green band shows a close relationship with the oxygen vacancies on (101) oriented anatase crystal surface. A blue shift of the photoluminescence spectra reveals that the defects of under-coordinated Ti(3+) ions transform to surface oxygen vacancies in the anatase TiO2 film annealing at temperature from 800°C to 900°C in N2 atmosphere.

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

    Science.gov (United States)

    Adamczyk, Anna; Długoń, Elżbieta

    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.

  20. Preparation of Oleyl Phosphate-Modified TiO2/Poly(methyl methacrylate Hybrid Thin Films for Investigation of Their Optical Properties

    Directory of Open Access Journals (Sweden)

    Masato Fujita

    2015-01-01

    Full Text Available TiO2 nanoparticles (NPs modified with oleyl phosphate were synthesized through stable Ti–O–P bonds and were utilized to prepare poly(methyl methacrylate- (PMMA- based hybrid thin films via the ex situ route for investigation of their optical properties. After surface modification of TiO2 NPs with oleyl phosphate, IR and 13C CP/MAS NMR spectroscopy showed the presence of oleyl groups. The solid-state 31P MAS NMR spectrum of the product revealed that the signal due to oleyl phosphate (OP shifted upon reaction, indicating formation of covalent Ti–O–P bonds. The modified TiO2 NPs could be homogeneously dispersed in toluene, and the median size was 16.1 nm, which is likely to be sufficient to suppress Rayleigh scattering effectively. The TEM images of TiO2/PMMA hybrid thin films also showed a homogeneous dispersion of TiO2 NPs, and they exhibited excellent optical transparency even though the TiO2 content was 20 vol%. The refractive indices of the OP-modified TiO2/PMMA hybrid thin films changed higher with increases in TiO2 volume fraction, and the hybrid thin film with 20 vol% of TiO2 showed the highest refractive index (n = 1.86.

  1. Synthesis and characterisations of Au-nanoparticle-doped TiO2 and CdO thin films

    Science.gov (United States)

    Gültekin, Aytaç; Karanfil, Gamze; Özel, Faruk; Kuş, Mahmut; Say, Ridvan; Sönmezoğlu, Savaş

    2014-06-01

    In the present study, pure and gold nanoparticle (Au NP)-doped titanium dioxide (TiO2) and cadmium oxide (CdO) thin film were prepared by the sol-gel method, and the effect of Au NP doping on the optical, structural and morphological properties of these thin films was investigated. The prepared thin films were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM) and ultraviolet-visible-near infrared (UV-Vis-NIR) spectra. While the optical band increases from 3.62 to 3.73 for TiO2 thin films, it decreases from 2.20 to 1.55 for CdO thin films with increasing Au doping concentration. Analysis of XRD indicates that the intensities of peaks of the crystalline phase have increased with the increasing Au NP concentrations in all thin films. SEM images demonstrate that the surface morphologies of the samples were affected by the incorporation of Au NPs. Consequently, the most significant results of the present study are that the Au NPs can be used to modify the optical, structural and morphological properties of TiO2 and CdO thin films.

  2. 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

  3. The directed preparation of TiO2 nanotubes film on FTO substrate via hydrothermal method for gas sensing application

    Directory of Open Access Journals (Sweden)

    Pham Van Viet

    2016-04-01

    Full Text Available In this research, we directly synthesized TiO2 nanotubes film on Fluorine doped Tin oxide (FTO substrate via hydrothermal method from commercial TiO2 in NaOH solution at 135 ℃ for 24 hours. The samples were characterized by X-ray diffraction (XRD pattern, field emission scanning electron microscopy (FESEM and transmitting electron microscopy (TEM. The average diameter of TiO2 nanotubes (TNTs is about 10–12 nm and their length is about a few hundred nanometers. The sensitivity ability of TNTs increases as the gas concentration increases and developing to the highest sensitivity of TNTs is 2.4 at 700 ppm of the ethanol concentration. The same as the gas concentration, the sensitivity of TNTs increases when the temperature increases. Besides, the sensitivity of samples at 250 ℃ is doubled compared to samples determined at 100 ℃.

  4. Influence of Yb-Doped Nanoporous TiO2 Films on Photovoltaic Performance of Dye-Sensitized Solar Cells

    Institute of Scientific and Technical Information of China (English)

    XU Wei-Wei; DAI Song-Yuan; HU Lin-Hua; LIANG Lin-Yun; WANG Kong-Jia

    2006-01-01

    @@ Yb-doped TiO2 pastes with different Yb/TiO2 weight ratios are prepared in the sol-gel process to obtain dyesensitized solar cells (DSCs). The nanocrystalline size of Yb-TiO2 becomes smaller and the lattice parameters change. Lattice distortion is observed and dark current is detected. It is found that a part of Yb existing as insulating oxide Yb2Oa state acts as barrier layers at the electrode-electrolyte interface to suppress charge recombination. A Yb-doped TiO2 electrode applied in DSCs leads to a higher open-circuit voltage and a higher fill factor. How the Yb-doped TiO2 films affect the photovoltaic response of DSCs is discussed.

  5. Fabrication and photoelectrochemical characteristics of In2S3 nano-flower films on TiO2 nanorods arrays

    Science.gov (United States)

    Han, Minmin; Yu, Limin; Chen, Wenyuan; Wang, Wenzhen; Jia, Junhong

    2016-04-01

    The In2S3 nano-flower films on TiO2/FTO (Fluorine-doped tin oxide) substrates were synthesized via hydrothermal method and the photoelectrochemical performances of In2S3/TiO2 photoelectrodes were characterized. The roles of PSS (poly(sodium-p-styrenesul-fonate)) and PEG (polyethylene glycol) on the structure controlling of In2S3 films were also discussed. The results show that the In2S3 nano-flower films consisted of ultrathin nanoflakes with a thickness of 5 nm are successfully grew on the surface of TiO2 nanorod arrays. PEG could play a role as the morphology-directing agent by confining crystal growth in certain directions, while PSS could provide coordination sites with long chains and lead to the formation of spherical structure. The energy conversion efficiency of In2S3 nano-flower/TiO2 photoelectrodes enhances thrice compared with that of bare TiO2 photoelectrode. This research presents further insight for improving the efficiency of semiconductors by using the suitable electron transfer channels, which may be promising for rational construction of solar conversion and storage devices.

  6. Effect of Aging Time and Film Thickness on the Photoelectrochemical Properties of TiO2 Sol-Gel Photoanodes

    Directory of Open Access Journals (Sweden)

    D. Regonini

    2014-01-01

    Full Text Available This work has focused on the investigation of a non-aqueous based sol-gel process to produce TiO2 based photoelectrodes for solar water splitting. In particular, the effect of the aging time of the sol and TiO2 film thickness on the photoelectrochemical properties of the photoanodes has been investigated. In order to achieve optimal performances (i.e., photocurrent density up to 570 µA/cm2 and IPCE of 26% at 300 nm, the sol needs to be aged for 3 to 6 h, before being dip-coated to produce the photoanodes. The importance of the aging time can also be appreciated from the optical properties of the TiO2 films; the absorbance threshold of the sol-gel aged for 3–6 h is slightly shifted towards longer wavelenghts in comparison to 0 h aging. Aging is necessary to build up a well-interconnected sol-gel network which finally leads to a photoelectrode with optimized light absorption and electron collection properties. This is also confirmed by the higher IPCE signal of aged photoelectrodes, especially below 340 nm. Among thicknesses considered, there is no apparent significant difference in the photoresponse (photocurrent density and IPCE of the TiO2 sol-gel films.

  7. Study of 44Ti grain boundary self-diffusion in thin nanocrystalline TiO2 films

    Energy Technology Data Exchange (ETDEWEB)

    Straumal, Petr [Institut fuer Materialphysik, Universitaet Muenster, D-48149 Muenster (Germany); National University of Science and Technology, MISIS, 119049 Moscow (Russian Federation); Divinski, Sergiy; Wilde, Gerhard [Institut fuer Materialphysik, Universitaet Muenster, D-48149 Muenster (Germany)

    2011-07-01

    Titanium dioxide is known for its photo-catalytic properties and enhanced corrosion resistance in aqueous environments. Due to these properties TiO2 is very attractive material for light-induced self-cleaning glass, water-cleaning and producing hydrogen from water applications. Numerous works are dedicated to the diffusion of various dopants like niobium or chromium in TiO2 but so far, none studied the self-diffusion of titanium in nanocrystalline TiO2. The grain boundary self-diffusion in thin nanocrystalline TiO2 films is investigated. The oxide films are produced using a novel deposition method from metal-organic precursors at relatively low (400-500 C) temperatures. A relaxation annealing at 800 C was performed. The diffusion was measured in temperature interval between 200 C and 600 C by means of the radiotracer technique applying the 44Ti isotope and utilizing ion beam sputtering for sectioning. The diffusion was measured at different oxygen pressures. In addition, the microstructure and its possible evaluation during diffusion annealing was investigated using TEM. The results are discussed with respect of the relationship between grain boundary self-diffusion and the synthesis pathway, the oxygen pressure and resulting microstructure of the nanoscale functional oxide films.

  8. Sunlight-Sensitive Anti-Fouling Nanostructured TiO2 coated Cu Meshes for Ultrafast Oily Water Treatment

    Science.gov (United States)

    Liu, Haoran; Raza, Aikifa; Aili, Abulimiti; Lu, Jinyou; Alghaferi, Amal; Zhang, Tiejun

    2016-05-01

    Nanostructured materials with desired wettability and optical property can play an important role in reducing the energy consumption of oily water treatment technologies. For effective oily water treatment, membrane materials with high strength, sunlight-sensitive anti-fouling, relative low fabrication cost, and controllable wettability are being explored. In the proposed oily water treatment approach, nanostructured TiO2-coated copper (TNS-Cu) meshes are used. These TNS-Cu meshes exhibit robust superhydrophilicity and underwater oleophobicity (high oil intrusion pressure) as well as excellent chemical and thermal stability (≈250 °C). They have demonstrated high separation efficiency (oil residue in the filtrate ≤21.3 ppm), remarkable filtration flux (≥400 kL h-1 m-2), and sunlight-sensitive anti-fouling properties. Both our theoretical analysis and experimental characterization have confirmed the enhanced light absorption property of TNS-Cu meshes in the visible region (40% of the solar spectrum) and consequently strong anti-fouling capability upon direct solar light illumination. With these features, the proposed approach promises great potential in treating produced oily wastewater from industry and daily life.

  9. A facile approach for high surface area electrospun TiO2 nanostructures for photovoltaic and photocatalytic applications.

    Science.gov (United States)

    Arun, T A; Madhavan, Asha Anish; Chacko, Daya K; Anjusree, G S; Deepak, T G; Thomas, Sara; Nair, Shantikumar V; Nair, A Sreekumaran

    2014-03-28

    A rice-shaped TiO2-ZnO composite was prepared by electrospinning a mixture comprising the precursors of TiO2 and ZnO in polyvinyl acetate polymer dissolved in N,N-dimethyl acetamide. The electrospun nanofibers upon heat treatment in air resulted in collapse of the continuous fiber morphology and the formation of the rice-shaped TiO2-ZnO composite. The TiO2-ZnO composite was then treated with dilute acetic acid under hydrothermal conditions to etch ZnO from the TiO2-ZnO composite to get coral-shaped anisotropic TiO2. The structural anisotropy of TiO2 produced by the selective etching of ZnO resulted in a high surface area of 148 m(2) g(-1) for the TiO2. The initial and final materials were characterized by scanning electron microscopy, transmission electron microscopy, Raman and XPS spectroscopies, powder X-ray diffraction and BET surface area measurements. The utility of the anisotropic TiO2 in photovoltaics and photocatalysis was explored. Dye-sensitized solar cells fabricated using the TiO2 showed a conversion efficiency of 6.54% as against 4.8% for a control experiment with the rice-shaped TiO2. The anisotropic TiO2 also showed good photocatalysis in the degradation of methyl orange dye and phenol.

  10. Performance of Erbium-doped TiO2 thin film grown by physical vapor deposition technique

    Science.gov (United States)

    Lahiri, Rini; Ghosh, Anupam; Dwivedi, Shyam Murli Manohar Dhar; Chakrabartty, Shubhro; Chinnamuthu, P.; Mondal, Aniruddha

    2017-09-01

    Undoped and Erbium-doped TiO2 thin films (Er:TiO2 TFs) were fabricated on the n-type Si substrate using physical vapour deposition technique. Field emission scanning electron microscope showed the morphological change in the structure of Er:TiO2 TF as compared to undoped sample. Energy dispersive X-ray spectroscopy (EDX) confirmed the Er doping in the TiO2 thin film (TF). The XRD and Raman spectrum showed the presence of anatase phase TiO2 and Er2O3 in the Er:TiO2 TF. The Raman scattering depicted additional number of vibrational modes for Er:TiO2 TF due to the presence of Er as compared to the undoped TiO2 TF. The UV-Vis absorption measurement showed that Er:TiO2 TF had approximately 1.2 times more absorption over the undoped TiO2 TF in the range of 300-400 nm. The main band transition, i.e., the transition between the oxygen (2p) state and the Ti (3d) state was obtained at 3.0 eV for undoped TiO2 and at 3.2 eV for Er:TiO2 TF, respectively. The photo responsivity measurement was done on both the detectors, where Er:TiO2 TF detector showed better detectivity ( D *), noise equivalent power and temporal response as compared to undoped detector under ultra-violet illumination.

  11. A Novel Regeneration Method of Cu(0)-deposited TiO2 Photocatalytic Film: Air-assisted Electrochemical Oxidation

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A rapid deactivation of TiO2 film was observed in the process of the photocatalytic degradation of formic acid in the presence of Cu(II) due to the deposition of Cu(0). A novel regeneration method, air-assisted electrooxidation, could efficiently retrieve the photocatalytic activity of the deact ivated film. HNO3 medium has a regeneration extent of 97.2% for first run, much higher than that of HCl and H2SO4 mediums.

  12. 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.

  13. Influence of temperature on the photodegradation process using Ag-doped TiO2 nanostructures: Negative impact with the nanofibers

    DEFF Research Database (Denmark)

    Barakata, Nasser A.M.; Kanjwal, Muzafar Ahmed; Chronakis, Ioannis S.

    2013-01-01

    In this study, the influence of the temperature on the photodegradation process using Ag-doped TiO2 nanostructures was investigated. Two morphologies were used; nanoparticles and nanofibers. The nanofibers were synthesized by electrospinning of a sol–gel consisting of titanium isopropoxide, silver......-doped TiO2 nanofibers for all formulations. The nanoparticles were prepared from the same sol–gels, however, instead of spinning the gels were dried, grinded and sintered at 700 °C. Photodegradation under UV irradiation for the rhodamine B at 5, 15, 25, 45 and 55 °C were performed. For the nanoparticles...

  14. Influence of temperature on the photodegradation process using Ag-doped TiO2 nanostructures: Negative impact with the nanofibers

    DEFF Research Database (Denmark)

    Barakata, Nasser A.M.; Kanjwal, Muzafar Ahmed; Chronakis, Ioannis S.

    2013-01-01

    In this study, the influence of the temperature on the photodegradation process using Ag-doped TiO2 nanostructures was investigated. Two morphologies were used; nanoparticles and nanofibers. The nanofibers were synthesized by electrospinning of a sol–gel consisting of titanium isopropoxide, silver......-doped TiO2 nanofibers for all formulations. The nanoparticles were prepared from the same sol–gels, however, instead of spinning the gels were dried, grinded and sintered at 700 °C. Photodegradation under UV irradiation for the rhodamine B at 5, 15, 25, 45 and 55 °C were performed. For the nanoparticles...

  15. Nanostructured poly (lactic acid) electrospun fiber with high loadings of TiO2 nanoparticles: Insights into bactericidal activity and cell viability.

    Science.gov (United States)

    Toniatto, T V; Rodrigues, B V M; Marsi, T C O; Ricci, R; Marciano, F R; Webster, T J; Lobo, A O

    2017-02-01

    Researchers have been looking for modifying surfaces of polymeric biomaterials approved by FDA to obtain nanofeatures and bactericidal properties. If modified, it would be very interesting because the antibiotic administration could be reduced and, therefore, the bacterial resistance. Here, we report the electrospinning of poly (lactic acid) (PLA) with high loadings of titanium dioxide nanoparticles (TiO2, 1-5wt%) and their bactericidal properties. TiO2 nanoparticles have been recognized for a long time for their antibacterial, low cost and self-cleaning properties. However, their ability to reduce bacteria functions when used in polymers has not been well studied to date. In this context, we aimed here to generate nanostructured PLA electrospun fiber-TiO2 nanoparticle composites for further evaluation of their bactericidal activity and cell viability. TEM and SEM micrographs revealed the successful electrospinning of PLA/TiO2 and the generation of polymer-TiO2 nanostructures. When increasing the TiO2 concentration, we observed a proportional increase in the nanoparticle density along the fiber and surface. The nanostructured PLA/TiO2 nanofibers showed no mammalian cell toxicity and, most importantly, possessed bactericidal activity with higher TiO2 loads. Such results suggest that the present PLA electrospun fiber-TiO2 nanoparticle composites should be further studied for a wide range of biomedical applications.

  16. 大规模生产TiO2薄膜的方法%Approach for Producing TiO2 Thin Films in Large Scale

    Institute of Scientific and Technical Information of China (English)

    汪洋; 彭晓光; 陈樱

    2007-01-01

    @@ Introduction Metal oxides are in use as catalysts in industrial processes. The surfaces of titanium dioxide (TiO2)has been of great interest because of its capability of heterogeneous catalysis and photocatalysis, and the adsorption of small molecules on TiO2 has received considerable attention in relation to the elimination of atmospheric pollutants. So that It is important to produce TiO2 thin films in large scale.

  17. A Spectroscopic Ellipsometry Study of TiO2 Thin Films Prepared by dc Reactive Magnetron Sputtering: Annealing Temperature Effect

    Institute of Scientific and Technical Information of China (English)

    Mati Horprathum; Pongpan Chindaudom; Pichet Limsuwan

    2007-01-01

    TiO2 thin Rims are obtained by dc reactive magnetron sputtering. A target of titanium (99.995%) and a mixture of argon and oxygen gases are used to deposit TiO2 films on to silicon wafers (100). The crystalline structure of deposited and annealed film are deduced by variable-angle spectroscopic ellipsometry (VASE) and supported by x-ray diffractometry. The optical properties of the Sims are examined by VASE. Measurements of ellipsometry are performed in the spectral range 0.72-3.55 eV at incident angle 75°. Several SE models, categorized by physical and optical models, are proposed based on the 'simpler better' rule and curve-fits, which are generated and compared to the experimental data using the regression analysis. It has been found that the triple-layer physical model together with the Cody-Lorentz dispersion model offer the most convincing result. The as-deposited films are found to be inhomogeneous and amorphous, whereas the annealed films present the phase transition to anatase and rutile structures. The refractive index of TiO2 thin films increases with annealing temperature. A more detailed analysis further reveals that thickness of the top sub-layer increases, whereas the region of the bottom amorphous sub-layer shrinks when the films are annealed at 300°C.

  18. The annealing temperature dependence of anatase TiO2 thin films prepared by the electron-beam evaporation method

    Science.gov (United States)

    Taherniya, Atefeh; Raoufi, Davood

    2016-12-01

    In this paper, we report on titanium dioxide (TiO2) thin films deposited by an electron beam evaporation method on quartz glass substrates (15 × 15 × 2 mm3 in size), followed by post-annealing at 300 °C to 600 °C for an annealing time of up to 2 h. The substrate temperature during the film deposition was kept at 150 °C. The effect of post-growth thermal annealing on the structural and optical properties of TiO2 thin films were systematically studied as a function of annealing temperature. We found that the as-deposited TiO2 films are amorphous in structure, while the films started to crystallize into the anatase phase when annealed at temperatures ≥450 °C. An increase in annealing temperature results in a decrease of transmittance percentage and also in optical band gap energy. The refractive indices of the films were evaluated from the measured transmittance spectra using the envelope method. An increase in the refractive index with an increase of annealing temperature was observed.

  19. Study of Optical Humidity Sensing Properties of Sol-Gel Processed TiO2 and MgO Films

    Directory of Open Access Journals (Sweden)

    B. C. Yadav

    2007-04-01

    Full Text Available Paper reports a comparative study of humidity sensing properties of TiO2 and MgO films fabricated by Sol-gel technique using optical method. One sensing element of the optical humidity sensor presented here consists of rutile structured two-layered TiO2 thin film deposited on the base of an isosceles glass prism. The other sensing element consists of a film of MgO deposited by same technique on base of the prism. Light from He-Ne laser enters prism from one of refracting faces of the prism and gets reflected from the glass-film interface, before emerging out from its other isosceles face. This emergent beam is allowed to pass through an optical fiber. Light coming out from the optical fiber is measured with an optical power meter. Variations in the intensity of light caused by changes in humidity lying in the range 5%RH to 95%RH have been recorded. MgO film shows better sensitivity than TiO2 film.

  20. Preparation of TiO2 thin film by the LPD method on functionalized organic self-assembled monolayers

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    In this paper, uniform titania (TiO2) films have been formed at 50℃ on silanol SAMs by the liquid-phase deposition (LPD) method at a temperature below 100℃. OTS (Octadecyltrichloro-Silane) selfassembled monolayers (SAMs) on glass wafers were used as substrates for the deposition of titanium dioxide thin films. This functionalized organic surface has shown to be effective for promoting the growth of films from titanic aqueous solutions by the LPD method at a low temperature below 100℃. The crystal phase composition, microstructure and topography of the as-prepared films were characterized by various techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The results indicate that the as-prepared thin films are purely crystallized anatase TiO2 constituted by nanorods after being annealed at 500℃. The pH values, concentration of reactants, and deposition temperatures play important roles in the growth of TiO2 thin films.