WorldWideScience

Sample records for films improve o2

  1. 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.

  2. 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.

  3. 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.

  4. Improvement in ferroelectricity of Hf x Zr1- x O2 thin films using ZrO2 seed layer

    Science.gov (United States)

    Onaya, Takashi; Nabatame, Toshihide; Sawamoto, Naomi; Ohi, Akihiko; Ikeda, Naoki; Chikyow, Toyohiro; Ogura, Atsushi

    2017-08-01

    The effect of crystallized ZrO2 (ZrO2-seed), amorphous Hf0.43Zr0.57O2 (HZO; HZO-seed), and amorphous Al2O3 (Al2O3-seed) seed layers on the ferroelectricity of HZO films was investigated. The remanent polarization (2P\\text{r} = P\\text{r} + - P\\text{r} - ) of a TiN-electroded capacitor with a ZrO2-seed layer was much larger than that of capacitors with a HZO-seed, Al2O3-seed, or no seed layer. Furthermore, the maximum 2P r was exhibited when the thickness of the ZrO2-seed layer was 2 nm. Large grain growth was observed, which satisfied the same lattice pattern between ZrO2 and HZO films, and indicates that the ZrO2 seed layer plays an important role in the nucleation of the HZO film.

  5. Effectively Improved SiO2-TiO2 Composite Films Applied in Commercial Multicrystalline Silicon Solar Cells

    Directory of Open Access Journals (Sweden)

    Chih-Hsiang Yang

    2013-01-01

    Full Text Available Composite silicon dioxide-titanium dioxide (SiO2-TiO2 films are deposited on a large area of 15.6 × 15.6 cm2 textured multicrystalline silicon solar cells to increase the incident light trapped within the device. For further improvement of the antireflective coatings (ARCs quality, dimethylformamide (DMF solution is added to the original SiO2-TiO2 solutions. DMF solution solves the cracking problem, thus effectively decreasing reflectance as well as surface recombination. The ARCs prepared by sol-gel process and plasma-enhanced chemical vapor deposition (PECVD on multicrystalline silicon substrate are compared. The average efficiency of the devices with improved sol-gel ARCs is 16.3%, only 0.5% lower than that of devices with PECVD ARCs (16.8%. However, from equipment depreciation point of view (the expiration date of equipment is generally considered as 5 years, the running cost (USD/watt of sol-gel technique is 80% lower than that of PECVD method for the first five years and 66% lower than that of PECVD method from the start of the sixth year. This result proves that sol-gel-deposited ARCs process has potential applications in manufacturing low-cost, large-area solar cells.

  6. Improvement of Optical Reactivity for Nano-TiO2 Film by Nitrogen ECR Plasma

    Institute of Scientific and Technical Information of China (English)

    Yuying XIONG; Tao MA; Linghong KONG; Junfang CHEN; Xianqiu WU; Honghua YU; Zhenxi ZHANG

    2006-01-01

    Nitrogen ion was implanted into the nano-TiO2 film surfaces by electron cyclotron resonance (ECR) plasma modification to improve the optical reactivity in visible-light region for nano-TiO2. Diagnosing the N2 plasma by optical emission spectroscopy (OES) was applied to the process of plasma modification. X-ray photoelectron spectroscopy (XPS) was used for analysis of the binding of element after plasma modification. It is shown that the surface modification was caused by excitated N. The injecting of N2 and N2+ leads to the increase in the dissociative interstitial state N in the films. The doped N makes for TiO2-xNx appearing in the TiO2films. TiO2-xNx forms the impurity energy state in the TiO2 energy band gap and reduces the energy band gap. This is the main reason leading to the red shift of absorption edge.

  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. 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.

  9. Underwater photosynthesis and respiration in leaves of submerged wetland plants: gas films improve CO2 and O2 exchange

    DEFF Research Database (Denmark)

    Colmer, Timothy David; Pedersen, Ole

    2007-01-01

    Many wetland plants have gas films on submerged leaf surfaces. We tested the hypotheses that leaf gas films enhance CO(2) uptake for net photosynthesis (P(N)) during light periods, and enhance O(2) uptake for respiration during dark periods. Leaves of four wetland species that form gas films......, and two species that do not, were used. Gas films were also experimentally removed by brushing with 0.05% (v/v) Triton X. Net O(2) production in light, or O(2) consumption in darkness, was measured at various CO(2) and O(2) concentrations. When gas films were removed, O(2) uptake in darkness was already...... diffusion-limited at 20.6 kPa (critical O(2) pressure for respiration, COP(R)>/= 284 mmol O(2) m(-3)), whereas for some leaves with gas films, O(2) uptake declined only at approx. 4 kPa (COP(R) 54 mmol O(2) m(-3)). Gas films also improved CO(2) uptake so that, during light periods, underwater P...

  10. Surviving floods: leaf gas films improve O2 and CO2 exchange, root aeration, and growth of completely submerged rice

    DEFF Research Database (Denmark)

    Pedersen, Ole; Rich, Sarah Meghan; Colmer, Timothy David

    2009-01-01

    When completely submerged, the leaves of some species retain a surface gas film. Leaf gas films on submerged plants have recently been termed 'plant plastrons', analogous with the plastrons of aquatic insects. In aquatic insects, surface gas layers (i.e. plastrons) enlarge the gas–water interface...... to promote O2 uptake when under water; however, the function of leaf gas films has rarely been considered. The present study demonstrates that gas films on leaves of completely submerged rice facilitate entry of O2 from floodwaters when in darkness and CO2 entry when in light. O2 microprofiles showed...... that the improved gas exchange was not caused by differences in diffusive boundary layers adjacent to submerged leaves with or without gas films; instead, reduced resistance to gas exchange was probably due to the enlarged water–gas interface (cf. aquatic insects). When gas films were removed artificially...

  11. 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%.

  12. Improved Resistive Switching Characteristics of Ag-Doped ZrO2 Films Fabricated by Sol-Gel Process

    Institute of Scientific and Technical Information of China (English)

    SUN Bing; LIU Li-Feng; HAN De-Dong; WANG Yi; LIU Xiao-Yan; HAN Ru-Qi; KANG Jin-Feng

    2008-01-01

    Ag-doped and pure ZrO2 thin films are prepared on Pt/Ti/SiO2/Si substrates by sol-gel process for resistive random access memory application. The highly reproducible resistive switching is achieved in the 10% Ag-doped ZrO2 devices. The improved resistive switching behaviour in the Ag doped ZrO2 devices could be attributed to Ag doping effect on the formation of the stable filamentary conducting paths. In addition, dual-step reset processes corresponding to three stable resistance states are observed in the 10% Ag doped ZrO2 devices, which may be implemented for the application of multi-bit storage.

  13. Improved Visible Transparency of SiO2/ZnO:Al/CeO2-TiO2/SiO2 Multilayer Films with High UV Absorption and Infrared Relfection Rate

    Institute of Scientific and Technical Information of China (English)

    NI Jiamiao; ZHAO Xiujian; ZHAO Qingnan; ZHENG Mindong

    2015-01-01

    New visible transparent, UV absorption, and high infrared reflection properties have been realized by depositing multilayer SiO2/ZnO: Al/CeO2-TiO2/SiO2 iflms onto glass substrates at low temperature by radio frequency magnetron sputtering. Optimum thickness of SiO2, ZnO: Al (ZAO) and CeO2-TiO2 (CTO) iflms were designed with the aid of thin iflm design software. The degree of antirelfection can be controlled by adjusting the thickness and refractive index. The outer SiO2 iflm can diminish the interference coloring and increase the transparency; the inner SiO2 iflm improves the adhesion of the coating on the glass substrate and prevents Ca2+, Na+ in the glass substrate from entering the ZAO iflm. The average transmittance in the visible light range increases by nearly 18%-20%, as compared to double layer ZAO/CTO iflms. And the iflms display high infrared relfection rate of above 75% in the wavelength range of 10-25 μm and good UV absorption (>98%) properties. These systems are easy to produce on a large scale at low cost and exhibit high mechanical and chemical durability. The triple functional iflms with high UV absorption, antirelfective and high infrared relfection rate will adapt to application in lfat panel display and architectural coating glass, automotive glass, with diminishing light pollution as well as decreasing eye fatigue and increasing comfort.

  14. Control and Monitoring of Dye Distribution in Mesoporous TiO2 Film for Improving Photovoltaic Performance.

    Science.gov (United States)

    Kim, Byung-Man; Han, Hyun-Gyu; Kim, Jeong Soo; Shin, HyeonOh; Kwon, Tae-Hyuk

    2017-01-25

    Dye distribution in a mesoporous TiO2 film is a key factor in the performance of dye-sensitized solar cells, but there has been little research on it. Here we report even dye distribution within the porous TiO2 film achieved by a physical driving force of gas flow. Gas-assisted dye arrangement, gas bubbling soaking (GBS), significantly accelerates the dye infiltration compared to conventional overnight soaking (OS). As a demonstration, we investigated the time-dependent dye infiltration using plasmon sensors. GBS produces an even vertical dispersion throughout the film, as illustrated by time-of-flight secondary ion mass spectrometry depth profiles. For devices using a 7-μm-thick active layer and a ruthenium-based dye (N719), only 15 min of GBS treatment produced better power conversion efficiency (PCE) than the optimal result from OS treatment (15 h), despite a lower dye capacity. Dual-GBS treatment (20 min for N719 and 10 min for YD2, a porphyrin dye) produced the best PCE (9.0%) in the device, which was ∼17% higher than that treated with dual-OS (10 h for N719 and 5 h for YD2). Such improvements are associated with reduced dye-free sites inside the porous TiO2 film after GBS treatment, leading to faster charge transport and slower charge loss.

  15. Porous TiO2-ZrO2 thin film formed by electrochemical technique to improve the biocompatibility of titanium alloy in physiological environment

    Science.gov (United States)

    Benea, L.; Dănăilă, E.; Ponthiaux, P.

    2017-02-01

    Porous Ti and Ti alloys have received increasing research interest for bone tissue engineering, especially for dental and orthopaedic implants because they provide cell ingrowths and vascularization, improving of adhesion and osseointegration. The tribocorrosion process is encountered in orthopaedic and dentistry applications, since it is known that the implants are often exposed to simultaneous chemical/electrochemical and mechanical stresses. The purpose of this study was to carry out a systematic investigation of the tribo-electrochemical performance of porous TiO2-ZrO2 thin film formed by anodization of Ti-10Zr alloy surface in an artificial saliva solution and to compare the resulted performance with that of the untreated Ti-10Zr alloy surface in order to be applied for biomedical use. The in situ electrochemical technique used for investigation of tribo-electrochemical degradation was the open circuit potential (OCP) measurement performed before, during and after sliding tests. The results presented herein show that controlled anodic oxidation method can significantly improve the tribocorrosion and friction performances of Ti-10Zr alloy surface intended for biomedical applications.

  16. Interconnected SnO2 Microsphere Films with Improved Ultraviolet Photodetector Properties

    Science.gov (United States)

    Xia, Weiwei; Li, Wanrong; Zeng, Xianghua; Shan, Dan; Lu, Junfeng; Wu, Guoqing; Dong, Jing; Zhou, Min

    2017-08-01

    Metal oxide nanostructure detectors must adsorb both oxygen molecules and incident light to achieve ultrahigh photogain. However, the oxygen adsorption and desorption process can prolong the photoresponse time of the photogain. Therefore, it is a challenge to fabricate such metal oxide nanostructures that have the ability to adsorb both oxygen molecules and incident light simultaneously to generate large amounts of carriers under light illumination, using a simple preparation method. In this work, self-connected core-shell SnO2 microspheres were prepared and used as a photodetector. The interconnected SnO2 device exhibited improved photoresponse properties with photocurrent of 15.4 μA at room temperature, representing a nearly 43-fold enhancement compared with traditional photodetectors. The underlying mechanism for this process was revealed by Hall mobility versus temperature and photocurrent versus power intensity characteristics. We found that conducting channels among the tightly interconnected microspheres are mainly responsible for the improved photocurrent response, providing effective paths for electron transport as well as available sites for charge carrier accumulation.

  17. Hybrid solar cells based on MEH-PPV and thin film semiconductor oxides (TiO2, Nb2O5, ZnO, CeO2 and CeO2–TiO2): Performance improvement during long-time irradiation

    DEFF Research Database (Denmark)

    Lira-Cantu, M.; Krebs, Frederik C

    2006-01-01

    prepared as bi-layers of thin film semiconducting oxides (TiO2, Nb2O5, ZnO, CeO2-TiO2 and CeO2) and the polymer MEH-PPV, with a final device configuration of ITO/ Oxide(thin) (film)/MEH-PPV/Ag. The oxides were prepared as thin transparent films from sol-gel solutions. The photovoltaic cells were studied......Performance improvement of hybrid solar cells (HSC) applying five different thin film semiconductor oxides has been observed during long-time irradiation in ambient atmosphere. This behavior shows a direct relation between HSC and oxygen content from the environment. Photovoltaic devices were...... with TiO2 thin films showed the best performance with maximum V-oc as high as -0.74V and I-sc of 0.4mA/cm(2). Solar decay analyses showed that the devices require a stabilization period of several hours in order to reach maximum performance. In the case of TiO2, Nb2O5 and CeO2-TiO2, the maximum current...

  18. Improved dielectric properties of CaCu3Ti4O12 films with a CaTiO3 interlayer on Pt/TiO2/SiO2/Si substrates prepared by pulsed laser deposition

    Science.gov (United States)

    Lee, Sung-Yun; Kim, Hui Eun; Jo, William; Kim, Young-Hwan; Yoo, Sang-Im

    2015-11-01

    We report the greatly improved dielectric properties of CaCu3Ti4O12 (CCTO) films with a 60 nm-thick CaTiO3 (CTO) interlayer on Pt/TiO2/SiO2/Si substrates. Both CCTO films and CTO interlayers were prepared by pulsed laser deposition (PLD). With increasing the thickness of CCTO from 200 nm to 1.3 μm, the dielectric constants ( ɛ r ) at 10 kHz in both CCTO single-layered and CCTO/CTO double-layered films increased from ˜260 to ˜6000 and from ˜630 to ˜3700, respectively. Compared with CCTO single-layered films, CCTO/CTO double-layered films irrespective of CCTO film thickness exhibited a remarkable decrease in their dielectric losses ( tanδ) (Poole-Frenkel conduction model. [Figure not available: see fulltext.

  19. Surfactant modified SnO2 nanostructured thin film for improved sensing performance of LPG and ammonia

    Science.gov (United States)

    Kumari, K. Prasanna; Thomas, Boben

    2017-05-01

    SnO2 nanostructured thin films have been successfully synthesized by way of spray pyrolysis from surfactant added solution. The X-ray diffraction pattern discloses the tetragonal rutile phase of the deposited SnO2 films, which experience a grain size reduction from 35 nm to 19 nm, on the addition of PVP surfactant in precursor. Gas sensing investigations on the surfactant modified film show considerable LPG and NH3 response at a lower operating temperature of 150°C. Quick response (˜20s) and fast recovery (˜30s) are the main features of these sensors. The measurement of AC conductivity of the sample allows understanding the conduction mechanism and sensing action for to enhance the detection sensitivity greatly.

  20. Improvement of electrical properties of Cu/SiCOH low-k film integrated system by O2 plasma treatment

    Institute of Scientific and Technical Information of China (English)

    Qian Xiao-Mei; Wei Yong-Xia; Yu Xiao-Zhu; Ye Chao; Ning Zhao-Yuan; Liang Rong-Qing

    2007-01-01

    This paper investigates the effect of O2 plasma treatment on the electric property of Cu/SiCOH low dielectric constant (low-k) film integrated structure. The results show that the leakage current of Cu/SiCOH low-k integrated structure can be reduced obviously at the expense of a slight increase in dielectric constant k of SiCOH films. By the Fourier transform infrared (FTIR) analysis on the bonding configurations of SiCOH films treated by O2 plasma, it is found that the decrease of leakage current is related to the increase of Si-O cages originating from the linkage of Si dangling bonjs through O, which makes the open pores sealed and reduces the diffusion of Cu to pores.

  1. Bilayer film electrode of brookite TiO2 particles with different morphology to improve the performance of pure brookite-based dye-sensitized solar cells

    Science.gov (United States)

    Xu, Jinlei; Wu, Shufang; Ri, Jin Hyok; Jin, Jingpeng; Peng, Tianyou

    2016-09-01

    A novel bilayer brookite TiO2 film photoanode consisting of quasi nanocube film as underlayer and rice-like submicrometer particle film as overlayer are fabricated for improving the photovoltaic properties of the pure brookite-based dye-sensitized solar cells (DSSCs). The brookite TiO2 nanocubes have a mean size of ∼50 nm, and the brookite TiO2 rice-like particles have diameter of ∼600 nm and length of ∼1100 nm. An optimal photovoltaic conversion efficiency of 5.51% is obtained from the bilayer brookite-based solar cell, with ∼41% improvement in the efficiency as compared to the single brookite nanocube film-based one (3.91%) under AM 1.5G one sun irradiation. The bilayer brookite-based solar cell shows not only reduced charge recombination and dark current, but also prolonged electron lifetime compared to the single brookite nanocube film-based one. All these lead to a higher photocurrent and voltage, and then to the improved efficiency of the brookite-based solar cell. The present results demonstrate a clear advance towards efficient improvement of the photovoltaic performance of pure brookite-based solar cells.

  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. Improvement of H2S Sensing Properties of SnO2-Based Thick Film Gas Sensors Promoted with MoO3 and NiO

    Directory of Open Access Journals (Sweden)

    In Sung Son

    2013-03-01

    Full Text Available The effects of the SnO2 pore size and metal oxide promoters on the sensing properties of SnO2-based thick film gas sensors were investigated to improve the detection of very low H2S concentrations (<1 ppm. SnO2 sensors and SnO2-based thick-film gas sensors promoted with NiO, ZnO, MoO3, CuO or Fe2O3 were prepared, and their sensing properties were examined in a flow system. The SnO2 materials were prepared by calcining SnO2 at 600, 800, 1,000 and 1,200 °C to give materials identified as SnO2(600, SnO2(800, SnO2(1000, and SnO2(1200, respectively. The Sn(12Mo5Ni3 sensor, which was prepared by physically mixing 5 wt% MoO3 (Mo5, 3 wt% NiO (Ni3 and SnO2(1200 with a large pore size of 312 nm, exhibited a high sensor response of approximately 75% for the detection of 1 ppm H2S at 350 °C with excellent recovery properties. Unlike the SnO2 sensors, its response was maintained during multiple cycles without deactivation. This was attributed to the promoter effect of MoO3. In particular, the Sn(12Mo5Ni3 sensor developed in this study showed twice the response of the Sn(6Mo5Ni3 sensor, which was prepared by SnO2(600 with the smaller pore size than SnO2(1200. The excellent sensor response and recovery properties of Sn(12Mo5Ni3 are believed to be due to the combined promoter effects of MoO3 and NiO and the diffusion effect of H2S as a result of the large pore size of SnO2.

  4. Improving Visible Light-Absorptivity and Photoelectric Conversion Efficiency of a TiO2 Nanotube Anode Film by Sensitization with Bi2O3 Nanoparticles

    Directory of Open Access Journals (Sweden)

    Menglei Chang

    2017-05-01

    Full Text Available This study presents a novel visible light-active TiO2 nanotube anode film by sensitization with Bi2O3 nanoparticles. The uniform incorporation of Bi2O3 contributes to largely enhancing the solar light absorption and photoelectric conversion efficiency of TiO2 nanotubes. Due to the energy level difference between Bi2O3 and TiO2, the built-in electric field is suggested to be formed in the Bi2O3 sensitized TiO2 hybrid, which effectively separates the photo-generated electron-hole pairs and hence improves the photocatalytic activity. It is also found that the photoelectric conversion efficiency of Bi2O3 sensitized TiO2 nanotubes is not in direct proportion with the content of the sensitizer, Bi2O3, which should be carefully controlled to realize excellent photoelectrical properties. With a narrower energy band gap relative to TiO2, the sensitizer Bi2O3 can efficiently harvest the solar energy to generate electrons and holes, while TiO2 collects and transports the charge carriers. The new-type visible light-sensitive photocatalyst presented in this paper will shed light on sensitizing many other wide-band-gap semiconductors for improving solar photocatalysis, and on understanding the visible light-driven photocatalysis through narrow-band-gap semiconductor coupling.

  5. Study on plasma pre-functionalized PVC film grafted with TiO2/PVP to improve blood compatible and antibacterial properties

    Science.gov (United States)

    Suganya, Arjunan; Shanmugavelayutham, Gurusamy; Serra Rodríguez, Carmen

    2017-04-01

    Research into the design of new biopolymers/polymer functionalized with nanoparticles is of tremendous interest to the medical sector, particularly with regard to blood-contacting devices. In this present study, a steady blood compatible and active antibacterial coating was fabricated by the grafting of titanium dioxide (TiO2)/polyvinylpyyrolidone (PVP) onto a polyvinyl chloride (PVC) film surface via the direct-current glow discharge plasma method. To enhance the chemical interaction between TiO2/PVP and PVC, the surfaces of the PVC films were functionalized by different plasmas (air, argon, and oxygen) before coating. In this study, the plasma parameters were varied, such as treatment time of about 5–20 min for a constant power of 100 W, potential 300 V, and a constant gas pressure of 2 Pa for air, argon, and oxygen gas environment. Then, the different plasma treatments on the PVC films, TiO2/PVP were grafted using a simple dip-coating method. In addition, the TiO2/PVP-grafted PVC films were characterized by contact angle, attenuated total reflectance Fourier transform infrared spectroscopy, field-emission scanning electron microscope, and x-ray photo electron spectroscopy. Importantly, TiO2/PVP is grafted onto the PVC surface due to the plasma-based retained functionality and demonstrates adhesive efficiency, which was observed by XPS. The bio-stability of the TiO2/PVP-modified PVC film was evaluated by in vitro platelet activation analysis and protein adsorption analysis. Then, the antibacterial properties were evaluated by the agar diffusion method against Escherichia coli. The result reveals that the grafting of TiO2/PVP was slightly higher for the 15 min oxygen plasma-functionalized PVC, which significantly decreases the platelet adhesion and protein adsorption. Moreover, the antibacterial properties of the 15 min oxygen plasma-functionalized PVC with TiO2/PVP-grafted film is also greatly improved compared with an air- and argon

  6. 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.

  7. SiO2-nanocomposite film coating of CAD/CAM composite resin blocks improves surface hardness and reduces susceptibility to bacterial adhesion.

    Science.gov (United States)

    Kamonwanon, Pranithida; Hirose, Nanako; Yamaguchi, Satoshi; Sasaki, Jun-Ichi; Kitagawa, Haruaki; Kitagawa, Ranna; Thaweboon, Sroisiri; Srikhirin, Toemsak; Imazato, Satoshi

    2017-01-31

    Composite resin blocks for computer-aided design/computer-aided manufacturing (CAD/CAM) applications have recently become available. However, CAD/CAM composite resins have lower wear resistance and accumulate more plaque than CAD/CAM ceramic materials. We assessed the effects of SiO2-nanocomposite film coating of four types of CAD/CAM composite resin blocks: Cerasmart, Katana Avencia block, Lava Ultimate, and Block HC on surface hardness and bacterial attachment. All composite blocks with coating demonstrated significantly greater Vickers hardness, reduced surface roughness, and greater hydrophobicity than those without coating. Adhesion of Streptococcus mutans to the coated specimens was significantly less than those for the uncoated specimens. These reduced levels of bacterial adherence on the coated surface were still evident after treatment with saliva. Surface modification by SiO2-nanocomposite film coating has potential to improve wear resistance and susceptibility to plaque accumulation of CAD/CAM composite resin restorations.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Improved performance of dye-sensitized solar cell based on TiO2 photoanode with FTO glass and film both treated by TiCl4

    Science.gov (United States)

    Li, Jinlun; Zhang, Haiyan; Wang, Wenguang; Qian, Yannan; Li, Zhenghui

    2016-11-01

    The dye-sensitized solar cell (DSSC) based on TiO2 photoanode with FTO glass and TiO2 film co-treated by TiCl4 were fabricated. The effects of TiCl4 treatment on the photovoltaic performance of the DSSCs were investigated. TiCl4 treatment of the FTO glass resulted in the formation of a compact TiO2 thin layer on its surface, which could increase the electron collection efficiency. Meanwhile, TiCl4 treatment of the TiO2 film could fill gaps between nanoparticles in the TiO2 film, leading to better electron transfer. These advantages make the DSSC exhibit a highest conversion efficiency of 3.34% under a simulated solar irradiation with an intensity of 100 mW/cm2 (1 sun), increased by 38% compared with that of the untreated DSSC.

  14. 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.

  15. 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.

  16. Protection effect of ZrO2 coating layer on LiCoO2 thin film fabricated by DC magnetron sputtering.

    Science.gov (United States)

    Noh, Jung-Pil; Jung, Ki-Taek; Jang, Min-Sun; Kwon, Tae-Hoon; Cho, Gyu-Bong; Kim, Ki-Won; Nam, Tae-Hyun

    2013-10-01

    Bare and ZrO2-coated LiCoO2 thin films were fabricated by direct current magnetron sputtering method on STS304 substrates. Deposited both films have a well-crystallized structure with (003) preferred orientation after annealing at 600 degrees C. The ZrO2-coated LiCoO2 thin film provide significantly improved cycling stability compared to bare LiCoO2 thin film at high cut-off potential (3.0-4.5 V). The improvement in electrochemical stability is attributed to the structural stability by ZrO2 coating layer.

  17. 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.

  18. Organic thin film transistors with a SiO2/SiNx/SiO2 composite insulator layer

    Institute of Scientific and Technical Information of China (English)

    Liu Xiang; Liu Hui

    2011-01-01

    We have investigated a SiO2/SiNx/SiO2 composite insulation layer structured gate dielectric for an organic thin film transistor (OTFT) with the purpose of improving the performance of the SiO2 gate insulator.The SiO2/SiNx/SiO2 composite insulation layer was prepared by magnetron sputtering.Compared with the same thickness of a SiO2 insulation layer device,the SiO2/SiNx/SiO2 composite insulation layer is an effective method of fabricating OTFT with improved electric characteristics and decreased leakage current.Electrical parameters such as carrier mobility by field effect measurement have been calculated.The performances of different insulating layer devices have been studied,and the results demonstrate that when the insulation layer thickness increases,the off-state current decreases.

  19. Improvement in reliability of amorphous indium-gallium-zinc oxide thin-film transistors with Teflon/SiO2 bilayer passivation under gate bias stress

    Science.gov (United States)

    Fan, Ching-Lin; Tseng, Fan-Ping; Li, Bo-Jyun; Lin, Yu-Zuo; Wang, Shea-Jue; Lee, Win-Der; Huang, Bohr-Ran

    2016-02-01

    The reliability of amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs) with Teflon/SiO2 bilayer passivation prepared under positive and negative gate bias stresses (PGBS and NGBS, respectively) was investigated. Heavier electrical degradation was observed under PGBS than under NGBS, indicating that the environmental effects under PGBS are more evident than those under NGBS. The device with bilayer passivation under PGBS shows two-step degradation. The positive threshold voltage shifts during the initial stressing period (before 500 s), owing to the charges trapped in the gate insulator or at the gate insulator/a-IGZO active layer interface. The negative threshold voltage shift accompanies the increase in subthreshold swing (SS) for the continuous stressing period (after 500 s) owing to H2O molecules from ambience diffused within the a-IGZO TFTs. It is believed that Teflon/SiO2 bilayer passivation can effectively improve the reliability of the a-IGZO TFTs without passivation even though the devices are stressed under gate bias.

  20. 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.

  1. Fabrication of Textured Rough SnO2:F Films on Glass Using TiO2 Film as a Buffer Layer

    Science.gov (United States)

    Ren, Yang; Wang, Qiuhong; Zhou, Xiaoge; Gao, Yun; Zhao, Gaoyang

    2017-08-01

    This study proposes an alternative method for preparing SnO2:F films with a pyramid-like surface morphology that are suitable for the transparent electrodes used in amorphous silicon thin-film solar cells. By introducing a TiO2 film as a buffer layer, the crystallographic orientation of the SnO2:F films was changed from random to a (200) plane, and the surface topography of the SnO2:F film transformed from rod-like to pyramid-like; hence, textured, rough SnO2:F films were obtained. An appropriately textured rough surface improves light-trapping and enhances the photocurrent in amorphous silicon thin-film solar cells. The textured SnO2:F films were used as the front electrode in a 1-cm2 single-junction amorphous silicon solar cell yielding an initial efficiency of 9.3%. Light-trapping in the textured SnO2:F films led to a photo-generated current higher than that generated in smooth films.

  2. 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.

  3. 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.

  4. Effects of SiO_2 and TiO_2 on resistance stabilities of flexible indium-tin-oxide films prepared by ion assisted deposition

    Institute of Scientific and Technical Information of China (English)

    LI Yuqiong; YU Zhinong; WANG Wuyu; FAN Yuejiang; DING Zhao; XUE Wei

    2009-01-01

    Inorganic buffer layers such as SiO_2 or TiO_2 and transparent conductive indium-tin-oxide (ITO) films were prepared on polyethylene terephthalate (PET) substrates by ion assisted deposition (LAD) at room temperature, and the effects of SiO_2 and TiO_2 on the bending resis-tance performance of flexible ITO films were investigated. The results show that ITO films with SiO_2 or TiO_2 buffer layer have better resis-tance stabihties compared to ones without the buffer layer when the ITO films are inwards bent at a bending radius more than 1.2 cm and when the ITO films are outwards bent at a bending radius from 0.8 cm to 1.2 cm. ITO films with SiO_2 buffer layer have better resistance sta-bilities compared to ones with TiO_2 buffer layer after the ITO Films are bent several hundreds of cycles at the same bending radius, for the adhesion of SiO_2 is stronger than that of TiO_2. The compressive stress resulted from inward bending leads to the formation of more defects in the ITO films compared with the tensile stress arising from outward bending. SiO_2 and TiO_2 buffer layers can effectively improve the crystal-linity of ITO films in (400), (440) directions.

  5. 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.

  6. Annealing of SnO2 thin films by ultra-short laser pulses

    NARCIS (Netherlands)

    Scorticati, D.; Illiberi, A.; Bor, Teunis Cornelis; Eijt, S.W.H.; Schut, H.; Römer, Gerardus Richardus, Bernardus, Engelina; de Lange, D.F.; Huis in 't Veld, Bert

    2014-01-01

    Post-deposition annealing by ultra-short laser pulses can modify the optical properties of SnO2 thin films by means of thermal processing. Industrial grade SnO2 films exhibited improved optical properties after picosecond laser irradiation, at the expense of a slightly increased sheet resistance

  7. Annealing of SnO2 thin films by ultra-short laser pulses

    NARCIS (Netherlands)

    Scorticati, D.; Illiberi, A.; Bor, T.; Eijt, S.W.H.; Schut, H.; Römer, G.R.B.E.; Lange, D.F. de; Huis In't Veld, A.J.

    2014-01-01

    Post-deposition annealing by ultra-short laser pulses can modify the optical properties of SnO2 thin films by means of thermal processing. Industrial grade SnO2 films exhibited improved optical properties after picosecond laser irradiation, at the expense of a slightly increased sheet resistance [Pr

  8. 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.

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

    Directory of Open Access Journals (Sweden)

    Lek Sikong

    2010-08-01

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

  10. Research of silane film cooperation with ZrO2 on electrogalvanized steel

    Institute of Scientific and Technical Information of China (English)

    Shuanghong WANG; Changsheng LIU; Haiyun YU

    2012-01-01

    The silane composite film formed on electrogalvanized steel sheet by silane film with ZrO2 improve the corrosion resistance.The surface morphology,the structure and composition as well as the corrosion resistance of the prepared silane composite film were investigated by SEM,AFM,XPS and electrochemical test.The experimental results showed that the structure of the silane composite film was composed of Si-O-Si three-dimensional network doped with ZrO2 showing excellent corrosion resistance,because the structure of this kind of composite film has much less micropore which improves the uniform and density of the silane film.

  11. Microstructures and magnetic properties of [SiO2/FePt]5/Ag thin films

    Institute of Scientific and Technical Information of China (English)

    FAN Jiu-ping; XU Xiao-hong; JIANG Feng-xian; TIAN Bao-qiang; WU Hai-shun

    2008-01-01

    [SiO2/FePt]5/Ag thin films were deposited by RF magnetron sputtering on the glass substrates and post annealing at 550 ℃for 30 min in vacuum. Vibrating sample magnetometer and X-ray diffraction analyser were applied to study the magnetic properties and microstructures of the films. The results show that without Ag underlayer [SiO2/FePt]5 films deposited onto the glass are FCC disordered; with the addition of Ag underlayer [SiO2/FePt]5/Ag films are changed into L10 and (111) mixed texture. The variation of the SiO2 nonmagnetic layer thickness in [SiO2/FePt]5/Ag films indicates that SiO2-doping plays an important role in improving the order parameter and the perpendicular magnetic anisotropy, and reducing the grain size and intergrain interactions. By controllingSiO2 thickness the highly perpendicular magnetic anisotropy can be obtained in the [SiO2 (0. 6nm)/FePt (3 nm)]5/Ag (50 nm) films and highly (001)-oriented films can be obtained in the [SiO2 (2 nm)/FePt (3 nm)]5/Ag (50 nm) films.

  12. Dielectric properties of PMMA-SiO2 hybrid films

    KAUST Repository

    Morales-Acosta, M. D.

    2010-03-01

    Organic-inorganic hybrid films were synthesized by a modified sol-gel process. PMMASiO2 films were prepared using methylmethacrylate (MMA), tetraethil-orthosilicate (TEOS) as silicon dioxide source, and 3-trimetoxi-silil-propil-methacrylate (TMSPM) as coupling agent. FTIR measurements were performed on the hybrid films to confirm the presence of PMMA-SiO2 bonding. In addition, metal-insulator-metal (MIM) devices were fabricated to study the dielectric constant of the films as function of frequency (1 KHz to 1 MHz). Electrical results show a weak trend of the dielectric constant of the hybrid films with MMA molar ratio. More importantly, the PMMA-SiO2 hybrid films showed a higher dielectric constant than SiO2 and PMMA layers, which is likely due to the presence of additional C-O-C bond. © (2010) Trans Tech Publications.

  13. RESONANT PHOTOEMISSION OF BULK CeO2 AND NANO—CeO2 FILMS

    Institute of Scientific and Technical Information of China (English)

    M.I.Abbas; K.Ibrahim; Z.Y.Wu; J.Zhang; F.Q.Liu; H.J.Qian

    2001-01-01

    Photoemission behaviors of nano-CeO2 films with parlicle sizes ranging from 8nm to 50nm and bulk CeO2 in Ce 4d-4f absorption region have been investigated.Resonant enhancements of Ce 4f valance band and Ce 5p bands for nano film and bulk material have been observed.The variation of electron density of Ce 4d-4f resonace.

  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. 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.

  16. RESONANT PHOTOEMISSION OF BULK CeO2 AND NANO-CeO2 FILMS

    Institute of Scientific and Technical Information of China (English)

    M.I. Abbas; K. Ibrahim; Z.Y. Wu; J. Zhang; F.Q. Liu; H.J. Qian

    2001-01-01

    Photoemission behaviors of nano-CeO2 films with particle sizes ranging from 8nm 1o50nm and bulk CeO2 in Ce 4d-4f absorption region have been investigated. Resonantenhancements of Ce 4f valance band and Ce 5p bands for nano film and bulk materialhave been observed. The variation of electron density of states in valance bands ofnano and bulk structures of CeO2 is discussed in terms of Ce 4d-4f resonance.

  17. 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.

  18. 光催化超亲水性TiO2-SiO2薄膜的研究%STUDY ON PHOTOCATALYTIC AND SUPER_HYDROPHILIC THIN FILMS OF TiO2-SiO2

    Institute of Scientific and Technical Information of China (English)

    陈文梅; 杨尊先; 赵修建; 余家国

    2001-01-01

    采用溶胶-凝胶法在普通载玻片上制备了TiO2-SiO2复合薄膜. 利用高温显微镜、SEM、红外光谱(IR)和分光光度计,研究了SiO2添加量和镀膜层数对润湿角、薄膜微结构、透过率、光催化活性的影响. 结果表明:通过在TiO2薄膜中加入SiO2,能显著降低薄膜的润湿角,超亲水性状态可以保持很长时间. 低于30% SiO2添加量(以摩尔分数计),在煅烧过程中对TiO2锐钛矿相晶粒生长有抑制作用,同时,光透过率提高,光催化活性有所下降. 在薄膜中, TiO2和SiO2分别单独形成颗粒,但有少量Ti—O—Si键形成,存在少量的复合氧化物. 当SiO2添加量为10%时, 3层TiO2-SiO2薄膜的润湿角接近0°,光催化活性为光照2 h甲基橙溶液降解率53%,其性能最佳.%TiO2-SiO2 thin films were prepared on slide glass substrates by sol-gel method. The influences of the amount of SiO2 addition and the coating cycle times of TiO2-SiO2 thin films on the microstructure, transmittance, contact angle of water and photocatalytic activity of TiO2-SiO2 thin films were investigated by using heating microscope, SEM and spectrophotometer. The results indicate that the contact angle of water is reduced as a result of adding SiO2 to TiO2 thin film. The super_hydrophilic state can be maintained for a long time. The addition of SiO2 less than 30% (in mole) has a suppressive effect on the crystal growth of anatase in calcination, and meanwhile, the transmittance is improved and the photocatalytic activity of TiO2 decreases slightly. With 10% (in mole) SiO2 addition and repeating the cycle 3 times, the contact angle of TiO2-SiO2 thin films is about 0° and the photocatalytic activity measurement shows that 53% methyl orange is degraded after irradiation for 2 h. The properties of the films are the best. Additionally, SiO2 and TiO2 form single oxide particles in the film, but a minor part of complex oxide may be formed due to the existance of

  19. 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.

  20. 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...

  1. Optical properties of CeO2 thin films

    Indian Academy of Sciences (India)

    S Debnath; M R Islam; M S R Khan

    2007-08-01

    Cerium oxide (CeO2) thin films have been prepared by electron beam evaporation technique onto glass substrate at a pressure of about 6 × 10-6 Torr. The thickness of CeO2 films ranges from 140–180 nm. The optical properties of cerium oxide films are studied in the wavelength range of 200–850 nm. The film is highly transparent in the visible region. It is also observed that the film has low reflectance in the ultra-violet region. The optical band gap of the film is determined and is found to decrease with the increase of film thickness. The values of absorption coefficient, extinction coefficient, refractive index, dielectric constant, phase angle and loss angle have been calculated from the optical measurements. The X-ray diffraction of the film showed that the film is crystalline in nature. The crystallite size of CeO2 films have been evaluated and found to be small. The experimental -values of the film agreed closely with the standard values.

  2. 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.

  3. 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%.

  4. Electrochemical and optical properties of CeO2-SnO2 and CeO2-SnO2:X (X = Li, C, Si films

    Directory of Open Access Journals (Sweden)

    Berton Marcos A.C.

    2001-01-01

    Full Text Available Thin solid films of CeO2-SnO2 (17 mol% Sn and CeO2-SnO2:X (X = Li, C and Si were prepared by the sol-gel route, using an aqueous-based process. The addition of Li, C and Si to the precursor solution leads to films with different electrochemical performances. The films were deposited by the dip-coating technique on ITO coated glass (Donnelly Glass at a speed of 10 cm/min and submitted to a final thermal treatment at 450 °C during 10 min in air. The electrochemical and optical properties of the films were determined from the cyclic voltammetry and chronoamperometry measurements using 0.1 M LiOH as supporting electrolyte. The ion storage capacity of the films was investigated using in situ spectroelectrochemical method and during the insertion/extraction process the films remained transparent. The powders were characterized by thermal analysis (DSC/TGA and X-ray diffraction.

  5. Effect of ambient oxygen pressure on structural, optical and electrical properties of SnO2 thin films

    Institute of Scientific and Technical Information of China (English)

    ZHAO Songqing; ZHOU Yueliang; WANG Shufang; ZHAO Kun; HAN Peng

    2006-01-01

    Polycrystalline SnO2 thin films were deposited on sapphire substrates at 450℃ under different ambient oxygen pressures by pulsed laser deposition technique. The effect of ambient oxygen pressure on the structural, optical and electrical properties of SnO2 thin films was studied. X-ray diffraction and Hall measurements show that increasing the ambient oxygen pressure can improve crystallization of the films and decrease resistivity of the films. A violet emission peak centered at 409 nm was observed from photoluminescence measurements for SnO2 films under deposition ambient oxygen pressure above 5 Pa, which is related to the improvement of crystalline of the films.

  6. 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.

  7. 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...

  8. A CdSe thin film: a versatile buffer layer for improving the performance of TiO2 nanorod array:PbS quantum dot solar cells

    Science.gov (United States)

    Tan, Furui; Wang, Zhijie; Qu, Shengchun; Cao, Dawei; Liu, Kong; Jiang, Qiwei; Yang, Ying; Pang, Shan; Zhang, Weifeng; Lei, Yong; Wang, Zhanguo

    2016-05-01

    To fully utilize the multiple exciton generation effects in quantum dots and improve the overall efficiency of the corresponding photovoltaic devices, nanostructuralizing the electron conducting layer turns out to be a feasible strategy. Herein, PbS quantum dot solar cells were fabricated on the basis of morphologically optimized TiO2 nanorod arrays. By inserting a thin layer of CdSe quantum dots into the interface of TiO2 and PbS, a dramatic enhancement in the power conversion efficiency from 4.2% to 5.2% was realized and the resulting efficiency is one of the highest values for quantum dot solar cells based on nanostructuralized buffer layers. The constructed double heterojunction with a cascade type-II energy level alignment is beneficial for promoting photogenerated charge separation and reducing charge recombination, thereby responsible for the performance improvement, as revealed by steady-state analyses as well as ultra-fast photoluminescence and photovoltage decays. Thus this paper provides a good buffer layer to the community of quantum dot solar cells.To fully utilize the multiple exciton generation effects in quantum dots and improve the overall efficiency of the corresponding photovoltaic devices, nanostructuralizing the electron conducting layer turns out to be a feasible strategy. Herein, PbS quantum dot solar cells were fabricated on the basis of morphologically optimized TiO2 nanorod arrays. By inserting a thin layer of CdSe quantum dots into the interface of TiO2 and PbS, a dramatic enhancement in the power conversion efficiency from 4.2% to 5.2% was realized and the resulting efficiency is one of the highest values for quantum dot solar cells based on nanostructuralized buffer layers. The constructed double heterojunction with a cascade type-II energy level alignment is beneficial for promoting photogenerated charge separation and reducing charge recombination, thereby responsible for the performance improvement, as revealed by steady

  9. 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.

  10. 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.

  11. Epitaxial Thin Films of Y doped HfO2

    Science.gov (United States)

    Serrao, Claudy; Khan, Asif; Ramamoorthy, Ramesh; Salahuddin, Sayeef

    Hafnium oxide (HfO2) is one of a few metal oxides that is thermodynamically stable on silicon and silicon oxide. There has been renewed interest in HfO2 due to the recent discovery of ferroelectricity and antiferroelectricity in doped HfO2. Typical ferroelectrics - such as strontium bismuth tantalate (SBT) and lead zirconium titanate (PZT) - contain elements that easily react with silicon and silicon oxide at elevated temperatures; therefore, such ferroelectrics are not suited for device applications. Meanwhile, ferroelectric HfO2 offers promise regarding integration with silicon. The stable phase of HfO2 at room temperature is monoclinic, but HfO2 can be stabilized in the tetragonal, orthorhombic or even cubic phase by suitable doping. We stabilized Y-doped HfO2 thin films using pulsed laser deposition. The strain state can be controlled using various perovskite substrates and controlled growth conditions. We report on Y-doped HfO2 domain structures from piezo-response force microscopy (PFM) and structural parameters via X-ray reciprocal space maps (RSM). We hope this work spurs further interest in strain-tuned ferroelectricity in doped HfO2.

  12. 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.

  13. 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.

  14. 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.

  15. Preparation and Characterization of CeO2-TiO2/SnO2:Sb Films Deposited on Glass Substrates by R.F.Sputtering

    Institute of Scientific and Technical Information of China (English)

    ZHAO Qingnan; DONG Yuhong; NI Jiamiao; WANG Peng; ZHAO Xiujian

    2008-01-01

    CeO2-TiO2 films and CeO2-TiO2/SnO2:Sb(6 mol%)double films were deposited on glass substrates by radio-frequency magnetron sputtering(R.F.Sputtering),using SnO2:Sb(6 mol%)target,and CeO2-TiO2 targets with different molar ratio of CeO2 to TiO2 (CeO2:TiO2=0:1.0;0.1:0.9;0.2:0.8;0.3:0.7;0.4:0.6;0.5:0.5;0.6:0.4; 0.7:0.3; 0.8:0.2;0.9:0.1;1.0:0).The films are characterized by UV-visible transmission and infrared reflection spectra,scanning electron microscopy(SEM),Raman spectroscopy,X-ray photoelectron spectroscopy(XPS)and X-ray diffraction(XRD),respectively.The obtained results show that the amorphous phases composed of CeO2-TiO2 play an important role in absorbing UV, there are Ce3+,Ce4+ and Ti4+ on the surface of the films;the glass substrates coated with CeO2-TiO2(Ce/Ti=0.5:0.5;0.6:0.4)/SnO2:Sb(6 mol%) double films show high absorbing UV(>99),high visible light transmission(75%)and good infrared reflection films can be used as window glass of buildings,automobile and so on.

  16. Characterization and antibacterial functions of Ag-TiO2 and W-TiO2 nanostructured thin films prepared by sol-gel/laser-induced technique

    Science.gov (United States)

    Joya, Y. F.; Liu, Z.; Wang, T.

    2011-11-01

    A novel sol-gel/laser-induced technique (SGLIT) has been developed to form nanocrystalline titanium dioxide (TiO2) based thin films with an improved antibacterial performance. TiO2 precursor films loaded with W+6 and Ag+2 ions (W-TiO2, Ag-TiO2) were prepared separately by sol-gel method and spin-coated on microscopic glass slides. As-dried films were subjected to KrF excimer laser pulses at optimized parameters to generate mesoporous anatase and rutile phases at room temperature. The anatase phase was obtained after irradiation with 10 laser pulses only at 75-85 mJ/cm2 fluence in W-TiO2 films. However, higher number of laser pulses and higher W+6 content favored the formation of rutile. Whereas Ag-TiO2 films exhibited anatase up to 200 laser pulses at the same fluence. The films were characterized by using XRD, FEG-SEM, TEM and UV-Vis spectrophotometer to investigate the crystallographic structure, phase transformation, surface morphology, film thickness and the optical properties. A crystallite size of approximately 20 nm was achieved from the anatase prepared by SGLIT. The films exhibited an enhanced antibacterial function against E-Coli cells under the UV excitation.

  17. 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.

  18. 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.

  19. 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.

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

    Science.gov (United States)

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

    2014-08-07

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

  1. Studies on the Surface Morphology and Orientation of CeO2 Films Deposited by Pulsed Laser Ablation

    Science.gov (United States)

    Develos, Katherine; Kusunoki, Masanobu; Ohshima, Shigetoshi

    1998-11-01

    We studied the surface morphology and orientation of CeO2 films grown by pulsed laser ablation (PLA) on r-cut (1\\=102) Al2O3 substrates and evaluated the effects of predeposition annealing conditions of Al2O3 and film thickness of CeO2. The annealing of Al2O3 substrates improves the smoothness of the surface and performing this in high vacuum leads to better crystallinity and orientation of deposited CeO2 films compared to those annealed in oxygen. A critical value of the film thickness was found beyond which the surface roughness increases abruptly. Atomic force microscopy (AFM) study showed that the surface of CeO2 films is characterized by a mazelike pattern. Increasing the film thickness leads to the formation of larger islands which cause the increase in the surface roughness of the films. The areal density and height of these islands increased with film thickness.

  2. Thermally induced crystallization in NbO2 thin films

    Science.gov (United States)

    Zhang, Jiaming; Norris, Kate J.; Gibson, Gary; Zhao, Dongxue; Samuels, Katy; Zhang, Minxian Max; Yang, J. Joshua; Park, Joonsuk; Sinclair, Robert; Jeon, Yoocharn; Li, Zhiyong; Williams, R. Stanley

    2016-09-01

    Niobium dioxide can exhibit negative differential resistance (NDR) in metal-insulator-metal (MIM) devices, which has recently attracted significant interest for its potential applications as a highly non-linear selector element in emerging nonvolatile memory (NVM) and as a locally-active element in neuromorphic circuits. In order to further understand the processing of this material system, we studied the effect of thermal annealing on a 15 nm thick NbO2 thin film sandwiched inside a nanoscale MIM device and compared it with 180 nm thick blanket NbOx (x = 2 and 2.5) films deposited on a silicon dioxide surface as references. A systematic transmission electron microscope (TEM) study revealed a similar structural transition from amorphous to a distorted rutile structure in both cases, with a transition temperature of 700 °C for the NbO2 inside the MIM device and a slightly higher transition temperature of 750 °C for the reference NbO2 film. Quantitative composition analysis from electron energy loss spectroscopy (EELS) showed the stoichiometry of the nominal 15 nm NbO2 layer in the as-fabricated MIM device deviated from the target 1:2 ratio because of an interaction with the electrode materials, which was more prominent at elevated annealing temperature.

  3. Thermally induced crystallization in NbO2 thin films

    Science.gov (United States)

    Zhang, Jiaming; Norris, Kate J.; Gibson, Gary; Zhao, Dongxue; Samuels, Katy; Zhang, Minxian Max; Yang, J. Joshua; Park, Joonsuk; Sinclair, Robert; Jeon, Yoocharn; Li, Zhiyong; Williams, R. Stanley

    2016-01-01

    Niobium dioxide can exhibit negative differential resistance (NDR) in metal-insulator-metal (MIM) devices, which has recently attracted significant interest for its potential applications as a highly non-linear selector element in emerging nonvolatile memory (NVM) and as a locally-active element in neuromorphic circuits. In order to further understand the processing of this material system, we studied the effect of thermal annealing on a 15 nm thick NbO2 thin film sandwiched inside a nanoscale MIM device and compared it with 180 nm thick blanket NbOx (x = 2 and 2.5) films deposited on a silicon dioxide surface as references. A systematic transmission electron microscope (TEM) study revealed a similar structural transition from amorphous to a distorted rutile structure in both cases, with a transition temperature of 700 °C for the NbO2 inside the MIM device and a slightly higher transition temperature of 750 °C for the reference NbO2 film. Quantitative composition analysis from electron energy loss spectroscopy (EELS) showed the stoichiometry of the nominal 15 nm NbO2 layer in the as-fabricated MIM device deviated from the target 1:2 ratio because of an interaction with the electrode materials, which was more prominent at elevated annealing temperature. PMID:27682633

  4. Effect of annealing ambient on SnO2 thin film transistors

    Science.gov (United States)

    D. M., Priyadarshini; Mannam, Ramanjaneyulu; Rao, M. S. Ramachandra; DasGupta, Nandita

    2017-10-01

    In this study, the effect of annealing ambient on SnO2 thin film transistors (TFTs) is presented. Phase pure SnO2 films have been deposited using solution processed spin coating technique with SnCl2 as the precursor material. The films are annealed at 500 °C for 1 h in different annealing ambient conditions with varying N2:O2 ratio. Top gate, bottom contact TFTs have been fabricated with SnO2 as the channel layer, silicon as the gate, silicon dioxide as the dielectric and gold as the contact material. XRD patterns reveal the amorphous nature of films. AFM image shows that the spin coated films are pin-hole free with extremely smooth surface morphology. PL and XPS measurements reveal that with increase in N2% during annealing, the defects in the films increase. However, with increase in nitrogen concentration, the device performance improves, the threshold voltage shifts towards lower values and mobility increases, but very high N2% is not suitable for device operation, a 70% N2 + 30% O2 annealing ambient is found to be suitable with devices showing saturation mobility of 0.23 cm2V-1s-1 and threshold voltage of 6.8 V and on/off ratio of 106.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  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. 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.

  12. The fabrication and photoelectrocatalytic study of composite ZnSe/Au/TiO2 nanotube films

    Science.gov (United States)

    Zhang, Guowei; Miao, Hui; Wang, Yongbo; Zhang, Dekai; Fan, Jun; Han, Tongxin; Mu, Jianglong; Hu, Xiaoyun

    2017-05-01

    In this paper, anatase TiO2 nanotube (NT) film photoelectrodes are successfully fabricated by a simple and effective hydrothermal method. Subsequently, an aqueous-phase processing technique is adopted to construct highly dispersed ZnSe quantum dots (QDs) on Au/TiO2 NT films prepared by microwave-assisted chemical reduction, which formed composite ZnSe/Au/TiO2 NT film systems (ZATs) with excellent performance in photoelectrocatalytic (PEC) applications. The morphology and performance of as-obtained ZATs were investigated based on various characterizations. The investigation revealed that as-obtained ZATs not only greatly extend spatial separation of charges and restrain the recombination rate of photogenerated electron-hole pairs, but also improve the efficiency to use visible light and display a wide and strong absorption in the visible light region ranging from 400 nm to 800 nm. Moreover, we observe a larger fluorescence quenching of ZATs compared with that of pure TiO2 NT films and binary composites. Experimental results indicate that the photocurrent densities of pure TiO2, 0.8 Au/TiO2, 60 min ZnSe/TiO2, and ZATs are 0.020 mA cm-2, 0.032 mA cm-2, 0.037 mA cm-2 and 0.070 mA cm-2, respectively, which is approximately 2-3.5 times higher than that of pure TiO2 NT films and binary compound photoelectrodes. Additionally, experimental results suggest that the as-prepared ZATs photoelectrode has exhibited considerable stability and significantly increased PEC activity for the degradation of methylene blue (MB) in distilled water under 100 mW cm-2 xenon lamp irradiation. The degradation efficiency on MB of 45 min ZnSe/0.8 Au/TiO2 NT films approaches 91%; however, the counterpart of TiO2 NT films is less than 10%. Eventually, the mechanism for the improvement of the PEC performance of ZATs is discussed to point out that ZATs display prominent charges transport performance, and a stepwise band alignment structure is built up in its photoelectrode, which indicates

  13. A comparative study of electroluminescence from Ge/SiO2 and Si/SiO2 films

    Institute of Scientific and Technical Information of China (English)

    Ma Shu-Yi; Chen Hui; Xiao Yong; Ma Zi-Jun; Sun Ai-Min

    2004-01-01

    Ge/SiO2 and Si/SiO2 films were deposited using the two-target alternation magnetron sputtering technique. The Au/Ge/SiO2/p-Si and Au/Si/SiO2/p-Si structures were fabricated and their electroluminescence (EL) characteristics were comparatively studied. Both Au/Ge/SiO2/p-Si and Au/Si/SiO2/p-Si structures have rectifying property. All the EL spectra from the two types of the structure have peak positions around 650-660 nm. The EL mechanisms of the structures are discussed.

  14. Improved dielectric constant and breakdown strength of γ-phase dominant super toughened polyvinylidene fluoride/TiO2 nanocomposite film: an excellent material for energy storage applications and piezoelectric throughput

    Science.gov (United States)

    Mehebub Alam, Md; Ghosh, Sujoy Kumar; Sarkar, Debabrata; Sen, Shrabanee; Mandal, Dipankar

    2017-01-01

    Titanium dioxide (TiO2) nanoparticles (NPs) embedded γ-phase containing polyvinylidene fluoride (PVDF) nanocomposite (PNC) film turns to an excellent material for energy storage application due to an increased dielectric constant (32 at 1 kHz), enhanced electric breakdown strength (400 MV m-1). It also exhibits a high energy density of 4 J cm-3 which is 25 times higher than that of virgin PVDF. 98% of the electroactive γ-phase has been acheived by the incorporation of TiO2 NPs and the resulting PNC behaves like a super-toughened material due to a dramatic improvement (more than 80%) in the tensile strength. Owing to their electroactive nature and extraordinary mechanical properties, PNC films have a strong ability to fabricate the piezoelectric nanogenerators (PNGs) that have recently been an area of focus regarding mechanical energy harvesting. The feasibility of piezoelectric voltage generation from PNGs is demostrated under the rotating fan that also promises further utility such as rotational speed (RPM) determination.

  15. Improved dielectric constant and breakdown strength of γ-phase dominant super toughened polyvinylidene fluoride/TiO2 nanocomposite film: an excellent material for energy storage applications and piezoelectric throughput.

    Science.gov (United States)

    Alam, Md Mehebub; Ghosh, Sujoy Kumar; Sarkar, Debabrata; Sen, Shrabanee; Mandal, Dipankar

    2017-01-06

    Titanium dioxide (TiO2) nanoparticles (NPs) embedded γ-phase containing polyvinylidene fluoride (PVDF) nanocomposite (PNC) film turns to an excellent material for energy storage application due to an increased dielectric constant (32 at 1 kHz), enhanced electric breakdown strength (400 MV m(-1)). It also exhibits a high energy density of 4 J cm(-3) which is 25 times higher than that of virgin PVDF. 98% of the electroactive γ-phase has been acheived by the incorporation of TiO2 NPs and the resulting PNC behaves like a super-toughened material due to a dramatic improvement (more than 80%) in the tensile strength. Owing to their electroactive nature and extraordinary mechanical properties, PNC films have a strong ability to fabricate the piezoelectric nanogenerators (PNGs) that have recently been an area of focus regarding mechanical energy harvesting. The feasibility of piezoelectric voltage generation from PNGs is demostrated under the rotating fan that also promises further utility such as rotational speed (RPM) determination.

  16. Synthesis and Characterization of SnO2 Thin Films by Chemical Bath Deposition

    Science.gov (United States)

    Rifai, Aditia; Iqbal, Muhammad; Nugraha; Nuruddin, Ahmad; Suyatman; Yuliarto, Brian

    2011-12-01

    SnO2 thin films were deposited on glass substrate by chemical bath deposition (CBD) with stannous chloride (SnCl2..2H2O) as a precursor and urea (CO(NH2)2) as a buffer. X-Ray Diffraction (XRD) are used to characterize the structure of the films; the surface morphology of the films were observed by Scanning Electron Microscope (SEM). Using this techniques, we specify the effect of stannous chloride concentration and weight ratio of urea/H2O on the crystallinity and morphology of these films. The rutile structure corresponding (110), (101) and (211) planes of SnO2 is obtained. The increasing of stannous chloride concentration and the decreasing weight ratio of urea/H2O is found to improve the crystallinity of the film. The average diameter of grain size is about 96 nm.

  17. The Effect of SiO2 Additive on Super-hydrophilic Property of TiO2-SiO2 Thin Film by Sol-gel Method

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    TiO2-SiO2 thin films have been prepared on slide glass substrates by sol-gel method, and the effect of SiO2 additive on photo-generated hydrophilicity of TiO2 thin film was investigated by measuring the contact angle of water, the microstructure, the transmittance, the photocatalytic activity and the specific surface area. The results showed that 10mol% of SiO2 additive was the most effective for decreasing contact angle of water. The SiO2 additive of less than 30mol% has a suppressive effect on the crystal growth of anatase in calcinations, resulting in a large surface area. Consequently, the super-hydrophilicity was improved.

  18. 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).

  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. 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.

  1. 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.

  2. 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.

  3. Study of p-type AlN-doped SnO2 thin films and its transparent devices

    Science.gov (United States)

    Wu, Y. J.; Liu, Y. S.; Hsieh, C. Y.; Lee, P. M.; Wei, Y. S.; Liao, C. H.; Liu, C. Y.

    2015-02-01

    The electrical properties of transparent Al-doped tin oxide (SnO2), N-doped SnO2, and AlN-doped SnO2 thin films were studied. The Al-doped tin oxide (SnO2) thin films all show n-type conduction regardless the annealing condition. The n-type conduction of the as-deposited N-doped SnO2, and AlN-doped SnO2 thin films could be converted to p-type conduction by annealing the films at an elevated temperature of 450 °C. XPS analysis verified that the substitution of N ions in the O ion sites in the annealed N-doped SnO2 and AlN-doped SnO2 thin films were responsible for the n-p conduction transition. The conduction of the annealed N-doped SnO2 and AlN-doped SnO2 thin films could be converted back to n-type conduction by thermally annealing the films at higher temperature, over 450 °C. The p-n conduction transition is related with the outgassing of N ions in the p-type N-doped SnO2 and AlN-doped SnO2 thin films. Remarkably, we found that the Al content can retard the outgassing of N ions in the p-type N-doped SnO2 and AlN-doped SnO2 thin films and prolong the p-n conduction transition temperature above 600 °C. XPS analysis revealed that the formation of the Snsbnd Nsbnd Al bond improved the stability of the N ions in the AlN-doped SnO2 thin films. I-V curve of the p-type AlN-doped SnO2/n-type fluorine-doped SnO2 junction exhibited clear p-n junction characteristics, a low leakage current under the revised bias (1.13 × 10-5 A at -5 V), and a low turn-on voltage (3.24 V). p-Type AlN-doped SnO2/n-type fluorine-doped SnO2 junction exhibited excellent transmittance (over 90%) in the visible region (470-750 nm).

  4. 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.

  5. Electrical Characterisation of Ferroelectric Field Effect Transistors based on Ferroelectric HfO2 Thin Films

    OpenAIRE

    Yurchuk, Ekaterina

    2015-01-01

    Ferroelectric field effect transistor (FeFET) memories based on a new type of ferroelectric material (silicon doped hafnium oxide) were studied within the scope of the present work. Utilisation of silicon doped hafnium oxide (Si:HfO2) thin films instead of conventional perovskite ferroelectrics as a functional layer in FeFETs provides compatibility to the CMOS process as well as improved device scalability. The influence of different process parameters on the properties of Si:HfO2 thin films ...

  6. 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.

  7. Comparison Between Research-Grade and Commercially Available SnO2 for Thin-Film CdTe Solar Cells: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Li, X.; Pankow, J.; To, B.; Gessert, T.

    2008-05-01

    Compared to commercial SnO2 (with similar film thickness and sheet resistance), research-grade SnO2 has higher optical transmittance and higher electron mobility. Based on our study, changing the glass substrate and improving the SnO2 quality could improve the optical properties of commercial SnO2.

  8. Preparation of Ag/TiO2/SiO2 films via photo-assisted deposition and adsorptive self-assembly for catalytic bactericidal application

    Science.gov (United States)

    Xi, Baojuan; Chu, Xiaona; Hu, Jiangyong; Bhatia, Charanjit Singh; Danner, Aaron James; Yang, Hyunsoo

    2014-08-01

    The deterioration of water supply quality due to the waterborne bacteria is an environmental problem requiring the urgent attention. Due to the excellent and synergic antimicrobial capability, Ag-loaded TiO2 photocatalyst emerges as a feasible measure to guard the water. In our work, Ag nanoparticles have been prepared by the photoassisted reduction of AgNO3 on the TiO2 film fabricated by solution-based adsorptive self-assembly approach. The role of surfactant on the growth rate and size controlling of particles is also studied. In this connection, different kinds of surfactants, such as PVP, Tween-20, Tween-40 and so on, are applied in the system to investigate the formation of Ag nanoparticles. The surface profile and elemental analysis of Ag/TiO2/SiO2 films are examined by scanning electron microscopy and attached energy-dispersive X-ray spectroscopy, respectively. In the anti-bacteria detection, Ag nanoparticles are found to enhance the bactericidal efficiency strongly comparing with the pure TiO2 film under the same condition. In addition, by comparison with Ag/TiO2/SiO2 film in the dark environment as the reference experiment, UV-visible light plays a vital role in the improved bactericidal behavior, demonstrating the more efficient charge separation induced by metal silver. Because of the versatility of the method, the present photoreductive route is also exploited for the synthesis of Au nanoparticles on TiO2/SiO2 films. The corresponding photocatalytical detection results demonstrate the loading of Au nanoparticles can improve the photodegradation efficiency of methyl orange assigned to the similar electron-trapping effect to silver.

  9. 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.

  10. Nanocrystalline SnO2:F thin films for liquid petroleum gas sensors.

    Science.gov (United States)

    Chaisitsak, Sutichai

    2011-01-01

    This paper reports the improvement in the sensing performance of nanocrystalline SnO(2)-based liquid petroleum gas (LPG) sensors by doping with fluorine (F). Un-doped and F-doped tin oxide films were prepared on glass substrates by the dip-coating technique using a layer-by-layer deposition cycle (alternating between dip-coating a thin layer followed by a drying in air after each new layer). The results showed that this technique is superior to the conventional technique for both improving the film thickness uniformity and film transparency. The effect of F concentration on the structural, surface morphological and LPG sensing properties of the SnO(2) films was investigated. Atomic Force Microscopy (AFM) and X-ray diffraction pattern measurements showed that the obtained thin films are nanocrystalline SnO(2) with nanoscale-textured surfaces. Gas sensing characteristics (sensor response and response/recovery time) of the SnO(2):F sensors based on a planar interdigital structure were investigated at different operating temperatures and at different LPG concentrations. The addition of fluorine to SnO(2) was found to be advantageous for efficient detection of LPG gases, e.g., F-doped sensors are more stable at a low operating temperature (300 °C) with higher sensor response and faster response/recovery time, compared to un-doped sensor materials. The sensors based on SnO(2):F films could detect LPG even at a low level of 25% LEL, showing the possibility of using this transparent material for LPG leak detection.

  11. Nanocrystalline SnO2:F Thin Films for Liquid Petroleum Gas Sensors

    Directory of Open Access Journals (Sweden)

    Sutichai Chaisitsak

    2011-07-01

    Full Text Available This paper reports the improvement in the sensing performance of nanocrystalline SnO2-based liquid petroleum gas (LPG sensors by doping with fluorine (F. Un-doped and F-doped tin oxide films were prepared on glass substrates by the dip-coating technique using a layer-by-layer deposition cycle (alternating between dip-coating a thin layer followed by a drying in air after each new layer. The results showed that this technique is superior to the conventional technique for both improving the film thickness uniformity and film transparency. The effect of F concentration on the structural, surface morphological and LPG sensing properties of the SnO2 films was investigated. Atomic Force Microscopy (AFM and X-ray diffraction pattern measurements showed that the obtained thin films are nanocrystalline SnO2 with nanoscale-textured surfaces. Gas sensing characteristics (sensor response and response/recovery time of the SnO2:F sensors based on a planar interdigital structure were investigated at different operating temperatures and at different LPG concentrations. The addition of fluorine to SnO2 was found to be advantageous for efficient detection of LPG gases, e.g., F-doped sensors are more stable at a low operating temperature (300 °C with higher sensor response and faster response/recovery time, compared to un-doped sensor materials. The sensors based on SnO2:F films could detect LPG even at a low level of 25% LEL, showing the possibility of using this transparent material for LPG leak detection.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Investigation of Ag-TiO2 Interfacial Reaction of Highly Stable Ag Nanowire Transparent Conductive Film with Conformal TiO2 Coating by Atomic Layer Deposition.

    Science.gov (United States)

    Yeh, Ming-Hua; Chen, Po-Hsun; Yang, Yi-Ching; Chen, Guan-Hong; Chen, Hsueh-Shih

    2017-03-29

    The atomic layer deposition (ALD) technique is applied to coat Ag nanowires (NWs) with a highly uniform and conformal TiO2 layer to improve the stability and sustainability of Ag NW transparent conductive films (TCFs) at high temperatures. The TiO2 layer can be directly deposited on Ag NWs with a surface polyvinylpyrrolidone (PVP) coat that acts a bed for TiO2 seeding in the ALD process. The ALD TiO2 layer significantly enhances the thermal stability at least 100 fold when aged between 200-400 °C and also provides an extra function of violet-blue light filtration for Ag NW TCFs. Investigation into the interaction between TiO2 and Ag reveals that the conformal TiO2 shell could effectively prevent Ag from 1D-to-3D ripening. However, Ag could penetrate the conformal TiO2 shell and form nanocrystals on the TiO2 shell surface when it is aged at 400 °C. According to experimental data and thermodynamic evaluation, the Ag penetration leads to an interlayer composed of mixed Ag-Ag2O-amorphous carbon phases and TiO2-x at the Ag-TiO2 interface, which is thought to be caused by extremely high vapor pressure of Ag at the Ag-TiO2 interface at a higher temperature (e.g., 400 °C).

  17. Preparation and Characterization of Super-Hydrophilic TiO2/SiO2 Composite Thin Films%超亲水TiO2/SiO2复合薄膜的制备与表征

    Institute of Scientific and Technical Information of China (English)

    余家国; 赵修建; 林立; 韩建军; 赵青南

    2001-01-01

    通过sol-gel工艺在普通钠钙玻璃表面制备了均匀透明的TiO2/SiO2复合薄膜。实验结果表明:在TiO2薄膜中添加SiO2,可以抑制薄膜中TiO2晶粒的长大,同时薄膜表面的羟基含量增加,水在复合薄膜表面的润湿角下降,亲水能力增强。当SiO2含量为10~20 mol%时获得了润湿角为0℃的超亲水性薄膜。%The uniform transparent TiO2/SiO2 composite thin films were prepared via sol-gel processing on the soda lime glass substrates. The addition of SiOn. to TiO2 thin films can suppress the grain growth of TiO2 crystal in the TiO2 thin films, increase the hydroxyl content of TiO2 film, low the contact angle for water of TiO2 films and enhance the hydrophilic property of TiO2 films. The super-hydrophilic TiO2/SiO2 composite films with the contact angle of 0° were obtained by the addition of 10mol%~20mol% SiO2.

  18. 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.

  19. Silicon surface passivation using thin HfO2 films by atomic layer deposition

    Science.gov (United States)

    Gope, Jhuma; Vandana; Batra, Neha; Panigrahi, Jagannath; Singh, Rajbir; Maurya, K. K.; Srivastava, Ritu; Singh, P. K.

    2015-12-01

    Hafnium oxide (HfO2) is a potential material for equivalent oxide thickness (EOT) scaling in microelectronics; however, its surface passivation properties particularly on silicon are not well explored. This paper reports investigation on passivation properties of thermally deposited thin HfO2 films by atomic layer deposition system (ALD) on silicon surface. As-deposited pristine film (∼8 nm) shows better passivation with <100 cm/s surface recombination velocity (SRV) vis-à-vis thicker films. Further improvement in passivation quality is achieved with annealing at 400 °C for 10 min where the SRV reduces to ∼20 cm/s. Conductance measurements show that the interface defect density (Dit) increases with film thickness whereas its value decreases after annealing. XRR data corroborate with the observations made by FTIR and SRV data.

  20. 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.

  1. 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....

  2. Superlattice Multinanolayered Thin Films of SiO2/SiO2 + Ge for Thermoelectric Device Applications

    Science.gov (United States)

    2013-04-05

    REPORT Superlattice multinanolayered thin films of SiO2/SiO2 + Ge for thermoelectric device applications 14. ABSTRACT 16. SECURITY CLASSIFICATION OF...used as a physical vapor deposition ( PVD ) system since we have used only two electron guns to evaporate the crucibles without any gas assistance. The

  3. Effects of O2 Plasma Treatment on the Chemical and Electric Properties of Low-k SiOF Films

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    With the progress of ULS1 technology, materials with low dielectric constant are required to replace SiO2 film as the interlayer to scale down the interconnection delay. Fluorinated Si oxide thin films (SiOF) are a promising material for the low dielectric constant and the process compatibility in existing technology. However, SiOF films are liable to absorb moisture. when exposed to air. By treating the SiOF films with O2 plasma, it was found that the moisture resistibility of SiOF films was remarkably improved. The mechanism of the improvement in stability of dielectric constant was investigated. The results show that: 1) F atoms dissociated from the films and the bond angle of Si-O-Si decreased. 2) The plasma treatment enhanced the strength of Si-F bonds by removing unstable =SiF2 structures in the films. Resistibility of SiOF films in moisture was improved.

  4. Laser-assisted structuring and modification of LiCoO2 thin films

    Science.gov (United States)

    Kohler, R.; Proell, J.; Ulrich, S.; Trouillet, V.; Indris, S.; Przybylski, M.; Pfleging, W.

    2009-02-01

    The material development of improved lithium ion batteries will play an important role in future mobile applications and energy storage systems. Electrode materials made of nano-composited materials are expected to improve battery lifetime and will lead to an enhancement of lithium diffusion and thus improve battery capacity and cyclability. In this study, research was conducted to further improve the electrochemical properties of thin film cathodes by increasing the surface to volume ratio and thereby the lithium intercalation rate. Cathode materials were synthesised by r.f. magnetron sputtering of LiCoO2 targets in a pure argon plasma. LiCoO2 films 3 μm thick and with a grain size of 10 to 500 nm were deposited on silicon and stainless steel substrates. The deposition parameters (argon pressure, substrate bias) were varied to create stoichiometric films with controlled nano-crystalline texture and morphology. During laser-assisted surface treatment, cone-shaped periodic surface structures were produced. For this purpose high repetition excimer laser radiation at wavelengths of 193 nm and 248 nm and with short laser pulse widths (4-6 ns) were used. Structure sizes varied with laser and processing parameters, e.g. laser fluences, pulse number, wavelength and processing gas. Laser annealing in air or furnace annealing in a controlled argon/oxygen environment were then used to create the high temperature phase of LiCoO2 (HT-LiCoO2). The sputtered films were studied with Raman spectroscopy, x-ray photoelectron spectroscopy and x-ray diffraction to determine their stoichiometry and crystallinity before and after laser treatment. The development of HT-LiCoO2 and also the formation of a Co3O4 phase were discussed. By means of electrochemical cycling, the performance of the manufactured films was investigated.

  5. 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.

  6. Ozone Treatment Improved the Resistive Switching Uniformity of HfAlO2 Based RRAM Devices

    Directory of Open Access Journals (Sweden)

    Lifeng Liu

    2015-01-01

    Full Text Available HfAlO2 based resistive random access memory (RRAM devices were fabricated using atomic layer deposition by modulating deposition cycles for HfO2 and Al2O3. Effect of ozone treatment on the resistive switching uniformity of HfAlO2 based RRAM devices was investigated. Compared to the as-fabricated devices, the resistive switching uniformity of HfAlO2 based RRAM devices with the ozone treatment is significantly improved. The uniformity improvement of HfAlO2 based RRAM devices is related to changes in compositional and structural properties of the HfAlO2 resistive switching film with the ozone treatment.

  7. 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...

  8. 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

  9. SiO2/TiO2 Nanocomposite Films on Polystyrene for Light-Induced Cell Detachment Application.

    Science.gov (United States)

    Cheng, Zhiguo; Cheng, Kui; Weng, Wenjian

    2017-01-25

    Light-induced cell detachment shows much potential in in vitro cell culture and calls for high-performance light-responsive films. In this study, a smooth and dense SiO2/TiO2 nanocomposite thin film with thickness of around 250 nm was first fabricated on H2O2 treated polystyrene (PS) substrate via a low-temperature sol-gel method. It was observed that the film could well-adhere on the PS surface and the bonding strength became increasingly high with the increase of SiO2 content. The peeling strength and shear strength reached 3.05 and 30.02 MPa, respectively. It was observed the surface of the film could transform into superhydrophilic upon 20 min illumination of ultraviolet with a wavelength of 365 nm (UV365). In cell culture, cells, i.e., NIH3T3 and MC3T3-E1 cells, cultured on SiO2/TiO2 nanocomposite film were easily detached after 10 min of UV365 illumination; the detachment rates reached 90.8% and 88.6%, respectively. Correspondingly, continuous cell sheets with good viability were also easily obtained through the same way. The present work shows that SiO2/TiO2 nanocomposite thin film could be easily prepared on polymeric surface at low temperature. The corresponding film exhibits excellent biocompatibility, high bonding strength, and good light responses. It could be a good candidate for the surface of cell culture utensils with light-induced cell detachment property.

  10. In vitro biocompatibility of titanium-nickel alloy with titanium oxide film by H2O2 oxidation

    Institute of Scientific and Technical Information of China (English)

    HU Tao; CHU Cheng-lin; YIN Li-hong; PU Yao-pu; DONG Yin-sheng; GUO Chao; SHENG Xiao-bo; CHUNG Jonathan-CY; CHU Paul-K

    2007-01-01

    Titanium oxide film with a graded interface to NiTi matrix was synthesized in situ on NiTi shape memory alloy(SMA) by oxidation in H2O2 solution. In vitro studies including contact angle measurement, hemolysis, MTT cytotoxicity and cell morphology tests were employed to investigate the biocompatibility of the H2O2-oxidized NiTi SMAs with this titanium oxide film. The results reveal that wettability, blood compatibility and fibroblasts compatibility of NiTi SMA are improved by the coating of titanium oxide film through H2O2 oxidation treatment.

  11. Application of nano-TiO2/LDPE composite film on photocatalytic oxidation degradation of dichloromethane.

    Science.gov (United States)

    Suwannahong, Kowit; Liengcharernsit, Winai; Sanongraj, Wipada; Kruenate, Jittiporn

    2012-09-01

    This study focused on the photocatalytic destruction of dichloromethane (DCM) in indoor air using the nano-TiO2/LDPE composite film as an economical photocatalyst. The nano-TiO2 was dispersed in a polyethylene matrix to form composite film. The photocatalytic activity of the nano-TiO2/LDPE composite films was evaluated through the degradation of dichloromethane(DCM) under UV-C irradiance at specific wavelength of 254 nm. The percentage of nano-TiO2 contents varied from 0, 5, and 10% (wt cat./wt LDPE composite film). The results derived from the kinetic model revealed that the photocatalytic rates of 5 and 10 wt.% nano-TiO2/ LDPE composite films follow the first order reaction while the rate of the film without TiO2 followed the zero order reaction. At low concentration of DCM, the rate of photocatalytic degradation of the DCM was slower than that at high DCM concentration. The 10 wt.% of TiO2 content of the nano-TiO2/LDPE composite film yielded the highest degradation efficiency of 78%, followed by the removal efficiency of 55% for the 5 wt.% of TiO2 content of the nano-TiO2/LDPE composite film. In contrast with the composite film containing nano-TiO2, the LDPE film without adding nano-TiO2 expressed the degradation efficiency of 28%.

  12. CMOS Compatible Nonvolatile Memory Devices Based on SiO2/Cu/SiO2 Multilayer Films

    Institute of Scientific and Technical Information of China (English)

    WANG Yan; LIU Qi; LV Hang-Bing; LONG Shi-Bing; ZHANG Sen; LI Ying-Tao; LIAN Wen-Tai; YANG Jian-Hong; LIU Ming

    2011-01-01

    We systematically investigate the resistive switching characteristics of SiO2 films with a Cu/SiO2/Cu/SiO2/Pt multilayer structure. The device exhibits good resistive switching performances,including a high ON/OFF resistance ratio (>103),good retention characteristic (>104 s),satisfactory switching endurance (>200cycles),a fast programming speed (<100ns) and a high device yield (~100%).Considering these results,SiO2-based memories have highly promising applications for nonvolatile memory devices.

  13. 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.

  14. 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.

  15. 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.

  16. Ferroelectricity of nondoped thin HfO2 films in TiN/HfO2/TiN stacks

    Science.gov (United States)

    Nishimura, Tomonori; Xu, Lun; Shibayama, Shigehisa; Yajima, Takeaki; Migita, Shinji; Toriumi, Akira

    2016-08-01

    We report on the impact of TiN interfaces on the ferroelectricity of nondoped HfO2. Ferroelectric properties of nondoped HfO2 in TiN/HfO2/TiN stacks are shown in capacitance-voltage and polarization-voltage characteristics. The Curie temperature is also estimated to be around 500 °C. The ferroelectricity of nondoped HfO2 clearly appears by thinning HfO2 film down to ˜35 nm. We directly revealed in thermal treatments that the ferroelectric HfO2 film on TiN was maintained by covering the top surface of HfO2 with TiN, while it was followed by a phase transition to the paraelectric phase in the case of the open surface of HfO2. Thus, it is concluded that the ferroelectricity in nondoped HfO2 in this study was mainly driven by both of top and bottom TiN interfaces.

  17. 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

  18. Studies on photocatalytic activity of Ag/TiO2 films

    Institute of Scientific and Technical Information of China (English)

    Hou Xinggang; Wu Xiaoling; Liu Andong

    2006-01-01

    Ag/TiO2 photocatalytic films were produced by hybrid sol-gel method.The photocatalytic degradation of methyl orange (MO) in aqueous solution under 365 nm irradiation on TiO2 and Ag/TiO2 thin films was investigated.The state and amount of Ag species within the film and the enhancement mechanism of photocatalytic activity of Ag/TiO2 were discussed.With a loading molar ratio of Ag/Ti = 0.135 in TiO2 film,the maximum catalytic efficiency was observed.

  19. 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.

  20. Preparation and Properties of Ag-TiO2 Thin Films on Glass Substrates

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Ag-TiO2 thin films were prepared on glasses.The morphology and structure of Ag-TiO2 films were investigated by XRD, SEM and FT-IR.The photocatalytic and hydrophilic properties of Ag-TiO2 thin films were also evaluated by examining photocatalytic degradation dichlorophos under sunlight illumination and the change of contact angle respectively.The research results show that the Ag-TiO2 thin film is mainly composed of 20-100nm Ag and TiO2 particles.The Ag-TiO2 thin films possess a super-hydrophilic ability and higher photocatalytic activity than that of pure TiO2 thin film.

  1. Fabrication of β-CuGaO2 thin films by ion-exchange of β-NaGaO2 thin films

    Science.gov (United States)

    Suzuki, Issei; Nagatani, Hiraku; Kita, Masao; Omata, Takahisa

    2017-09-01

    β-CuGaO2 shows promise as an absorber material for use in thin-film solar cells because of its direct and narrow band gap, causing intense light absorption and high theoretical maximum conversion efficiency. β-CuGaO2 thin films were fabricated using an ion-exchange whereby Na+ ions within a sputtered β-NaGaO2 thin film were replaced with Cu+ ions from a CuCl vapor. The band gap of the film was 1.45 eV, almost identical to that of the bulk material. The basic framework of the crystal structure and the orientation of the film were preserved following the ion-exchange. Methods of obtaining high-quality, stoichiometric β-CuGaO2 thin films free of cracks are discussed.

  2. 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.

  3. 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.

  4. Dynamic behavior of surface film on LiCoO 2 thin film electrode

    Science.gov (United States)

    Matsui, Masaki; Dokko, Kaoru; Kanamura, Kiyoshi

    Electrochemical oxidation behavior of non-aqueous electrolytes on LiCoO 2 thin film electrodes were investigated by in situ polarization modulation Fourier transform infrared (PM-FTIR) spectroscopy, atomic force microscopy and X-ray photoelectron spectroscopy (XPS). LiCoO 2 thin film electrode on gold substrate was prepared by rf-sputtering method. In situ PM-FTIR spectra were obtained at various electrode potentials during cyclic voltammetry measurement between 3.5 V vs. Li/Li + and 4.2 V vs. Li/Li +. During anodic polarization, oxidation of non-aqueous electrolyte was observed, and oxidized products remained on the electrode at the potential higher than 3.75 V vs. Li/Li + as a surface film. During cathodic polarization, the stripping of the surface film was observed at the potential lower than 3.9 V vs. Li/Li +. Depth profile of XPS also showed that more organic surface film remained on charged LiCoO 2 than that on discharged one. AFM images of charged and discharged electrodes showed that some decomposed products deposited on charged electrode and disappeared from the surface of discharged one. These results indicate that the surface film on LiCoO 2 is not so stable.

  5. Photoelectric properties of TiO2-ZrO2 thin films prepared by sol-gel method.

    Science.gov (United States)

    Zhang, Haifeng; Ruan, Shengping; Feng, Caihui; Xu, Baokun; Chen, Weiyou; Dong, Wei

    2011-11-01

    Acidic sols of TiO2, ZrO2 and Ti-Zr mixed oxide precursors were prepared. The sols were then smeared on quartz substrate and annealed at 650 degrees C for 2 hour to form polycrystalline oxide films. XRD, SEM, UV-visible absorption spectra and XPS were carried out to characterize the films. It was found that the crystalline phase of pure titania is an anatase and pure zirconia is a tetragonal. The binary oxides show the anatase phase at the molar ratio of Ti:Zr = 2.73:1, which means that solid solution was formed. The absorption edge of the TiO2-ZrO2 binary oxides showed obvious blue shift as the Zr ratio increased. The results obtained indicate that the band gap of the binary oxides could be adjusted from 3.2 eV (TiO2) to 7.8 eV (ZrO2) by varying the molar ratio of Ti and Zr. Au interdigitated electrodes were produced by planar technology and MSM (metal-semiconductor-metal) structure UV detector based on TiO2-ZrO2 binary oxides was fabricated. Obvious photoelectric response was observed.

  6. Characteristics of SnO2 thin films prepared by SILAR

    Science.gov (United States)

    Yıldırım, M. Ali; Akaltun, Yunus; Ateş, Aytunç

    2012-09-01

    SnO2 thin films were deposited on glass substrates by using Successive Ionic Layer Adsorption and Reaction (SILAR) method at room temperature. The film thickness effect on characteristic parameters such as structural, morphological, optical and electrical properties of the films was studied. Also, the films were annealed in oxygen atmosphere (400 °C, 30 min) and characteristic parameters of the films were investigated. The X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) studies showed that all the films exhibited polycrystalline nature with tetragonal structure and were covered well on glass substrates. After the investigation of the crystalline and surface properties of the films, it was found that they were improving with increasing film thickness. Optical band gap decreased from 3.90 eV to 3.54 eV and electrical conductivity changed between 0.015-0.815 (Ω-cm)-1as the film thickness increased from 215 to 490 nm. The refractive index (n), optical static and high frequency dielectric constants (ɛo, ɛ∞) values were calculated by using the optical band gap values as a function of the film thickness.

  7. Near Infrared Photoluminescence from Yb,Al Co-implanted SiO2 Films on Silicon

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jian-Guo; WANG Xiao-Xin; CHENG Bu-Wen; YU Jin-Zhong; WANG Qi-Ming

    2006-01-01

    @@ Intense room-temperature near infrared (NIR) photoluminescence (980 nm and 1032nm) is observed from Yb, Al co-implanted SiO2 films on silicon. The optical transitions occur between the 2F5/2 and 2F7/2 levels of Yb3+ in SiO2. The additional Al-implantation into SiO2 films can effectively improve the concentration quenching effect of Yb3+ in SiO2. Photoluminescence excitation spectroscopy shows that the NIR photoluminescence is due to the non-radiative energy transfer from Al-implantation-induced non-bridging oxygen hole defects in SiO2 to Yb3+ in the Yb-related luminescent complexes. It is believed that the defect-mediated luminescence of rare-earth ions in SiO2 is very effective.

  8. Wide temperature polyimide/ZrO2 nanodielectric capacitor film with excellent electrical performance

    Science.gov (United States)

    Zou, C.; Kushner, D.; Zhang, S.

    2011-02-01

    In this letter, wide temperature dielectric properties and corona resistance of Upilex-S® polyimide (PI) films filled with Zirconium dioxide (ZrO2) nanoparticles were investigated. ZrO2/PI nanodielectrics exhibited the stable dielectric properties, high energy density and high charge-discharge efficiency below 300 °C. Testing of corona resistance showed even a small amount of nanofillers can improve the lifetime of PI significantly. Scanning electron microscopy with x-ray microanalysis (SEM-EDS) analysis suggested the higher thermal conductivity and evaporation of ZrO2 nanoparticles may induce this improvement. These high performance features make polyimide nanocomposites attractive for high energy density capacitor applications at high temperature.

  9. 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.

  10. UV/TiO2 and UV/TiO2-film for Degradation of Textile Dyes

    Institute of Scientific and Technical Information of China (English)

    Ruth Yu-li Yeh; Shen P W; Liu Robert; Hung Yung-tse

    2007-01-01

    This research focused on the feasibility and treatment efficiency of Advance Oxidation Process (AOP)-UV/TiO2 for three different kinds of simulated dye wastewater (FBL, FBB and S-RL). The first part of this study investigated the treatment of simulated dye wastewater with UV/TiO2 by changing TiO2 dosages, TiO2 particle sizes and dye concentrations. The efficiency was measured by color removal and TOC removal. The optimum conditions obtained for treatment of different dye wastewater were different. The treatment of Indanthrene red (FBB) by UV/TiO2 was the best, with 99.68% of TOC removal percentage and nearly 100% of color removal while treatment of FBL with 96.11% of TOC removal and almost 100% of color removal. The removal efficiency was lowest for S-RL dye solution with 81.88% of TOC and 95.87% for color removal. Both Langmuir adsorption isotherm and modified Langmuir-Hinshelwood kinetic model (modified L-H model) were fitted to the experimental data and were able to correlate the adsorption patterns and the kinetics of the dyes studied. Since the photocatalysts (TiO2) used were nano-sized powder and is difficult to separate from the wastewater, the second part of this research focuses on the preparation of TiO2-film on glass-substrate and the treatment of simulated FBL dye wastewater by UV/TiO2-film oxidation then followed. The experimental results showed the TiO2-films are suitable only for the dye wastewater treatment in low concentration.

  11. 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.

  12. HT-LiCoO2 Thin Film Positive Electrodes Prepared by RF Magnetron Sputtering

    Science.gov (United States)

    Kumar, P. Jeevan; Babu, K. Jayanth; Hussain, O. M.

    2011-07-01

    Thin films of LiCoO2 prepared by RF magnetron sputtering on Si/SiO2/Ti/Au substrates are investigated microstructural and electrochemical properties. The as deposited film shown layered with (003) preferred orientation. After annealing at 923 K in presence of O2 ambient (5×10-2 mbar), HT hexagonal phase LiCoO2 is obtained for the films deposited at O2 to Ar ratio 1:9 and at substrate temperature 523 K. LiCoO2 deposit is unambiguously shown two Raman bands at 465 and 545 cm-1 confirming layered hexagonal structure. Also, studied the performance of the LiCoO2 as positive electrode in aqueous (Pt// LiCoO2) and non-aqueous (Li// LiCoO2) Li-ion rechargeable batteries.

  13. Reactive sputtering deposition of SiO2 thin films

    Directory of Open Access Journals (Sweden)

    IVAN RADOVIC

    2008-01-01

    Full Text Available SiO2 layers were deposited in a UHV chamber by 1 keV Ar+ ion sputtering from a high purity silicon target, using different values of the oxygen partial pressure (5×10-6–2×10-4 mbar and of the ion beam current on the target (1.67–6.85 mA. The argon partial pressure during operation of the ion gun was 1×10-3 mbar. The substrate temperature was held at 550 °C and the films were deposited to a thickness of 12.5–150 nm, at a rate from 0.0018–0.035 nm s-1. Structural characterization of the deposited thin films was performed by Rutherford backscattering spectrometry (RBS analysis. Reactive sputtering was proved to be efficient for the deposition of silica at 550 °C, an oxygen partial pressure of 2×10-4 mbar (ion beam current on the target of 5 mA or, at a lower deposition rate, ion beam current of 1.67 mA and an oxygen partial pressure of 6×10-5 mbar. One aspect of these investigations was to study the consumption of oxygen from the gas cylinder, which was found to be lower for higher deposition rates.

  14. 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.

  15. 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.

  16. Photoelectrocatalytic Degradation of Organic Pollutants in Aqueous Solution Using a Pt-TiO2 Film

    OpenAIRE

    Chun He; Mudar Abou Asi; Ya Xiong; Dong Shu; Xiangzhong Li

    2009-01-01

    A series of Pt-TiO2 films with nanocrystaline structure was prepared by a procedure of photodeposition and subsequent dip-coating. The Pt-TiO2 films were characterized by X-ray diffraction, scanning electronic microscope, electrochemical characterization to examine the surface structure, chemical composition, and the photoelectrochemical properties. The photocatalytic activity of the Pt-TiO2 films was evaluated in the photocatalytic (PC) and photoelectrocatalytic (PEC) degradation of formic ...

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. LiCoO2 and SnO2 Thin Film Electrodes for Lithium-Ion Battery Applications

    Science.gov (United States)

    Maranchi, Jeffrey P.; Hepp, Aloysius F.; Kumta, Prashant N.

    2004-01-01

    There is an increasing need for small dimension, ultra-lightweight, portable power supplies due to the miniaturization of consumer electronic devices. Rechargeable thin film lithium-ion batteries have the potential to fulfill the growing demands for micro-energy storage devices. However, rechargeable battery technology and fabrication processes have not kept paced with the advances made in device technology. Economical fabrication methods lending excellent microstructural and compositional control in the thin film battery electrodes have yet to be fully developed. In this study, spin coating has been used to demonstrate the flexibility of the approach to produce both anode (SnO2) and cathode (LiCoO2) thin films. Results on the microstructure crystal structure and electrochemical properties of the thin film electrodes are described and discussed.

  2. Effect of oxidizing agents in CeO2 thin film formation.

    Science.gov (United States)

    Yadav, S. M.; Sartale, S. D.

    2012-06-01

    Cerium Oxide (CeO2) thin films have been prepared by oxidative soak method onto glass substrates using NaNO2 and NaBrO3 oxidizing agents. Because of different oxidation strength different crystallinity, morphology and optical properties of the CeO2 films have been observed. Furthermore it has been observed that crystalline, transparent and crack free CeO2 thin films can be obtained using NaNO2 oxidizing agent. On the other hand CeO2 thin films deposited by using NaBrO3 oxidizing agent are amorphous, less transparent and porous with large number of cracks.

  3. 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.

  4. 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.

  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. 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.

  7. Nano-TiO2@Ag/PVC film with enhanced antibacterial activities and photocatalytic properties

    Science.gov (United States)

    Liu, Fajia; Liu, Hu; Li, Xiaoyun; Zhao, Huanyu; Zhu, Danping; Zheng, Yingying; Li, Chaorong

    2012-03-01

    The antibacterial and photocatalytic PVC film was prepared by doping heteronanostructure of TiO2 nanowire@Ag nanoparticles. TiO2 nanowire with 50-60 nm in diameter and 0.1 mm in length was prepared by a hydrothermal method, and Ag nanopartical about 5-10 nm in diameter was grafted on the surface of TiO2 nanowire evenly in the solution. The antimicrobial ability and the photocatalytic properties of the nano-TiO2@Ag/PVC film were systematically investigated by changing the influence factors such as the content of nano-TiO2@Ag, pH value and the cultivation condition. It confirmed that the nano-TiO2@Ag nanostructure could increase the antibacterial efficiency of the PVC film. Further, nano-TiO2@Ag/PVC film also showed enhanced photocatalytic activity to decompose Rhodmine B (RhB).

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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).

  13. 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.

  14. Enhancement of supercapacitance property of electrochemically deposited MnO2 thin films grown in acidic medium

    Science.gov (United States)

    Jana, S. K.; Rao, V. P.; Banerjee, S.

    2014-02-01

    In this communication we present supercapacitance property of MnO2 thin-films which are fabricated on stainless steel (SS) substrate by electro-deposition method carried out in different pH of the electrolyte. A significant improvement of the device performance of acid mediated grown (AMG) MnO2 over normal MnO2 (grown in neutral medium) has been achieved. We have also investigated role of interfacial structure on the internal resistance of the device material. AMG MnO2 film exhibits superior device performance with specific capacitance of 652 F/g which is 2 times better than that obtained in normal MnO2 and also energy density of 90.69 Wh/kg.

  15. 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.

  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. Synthesis, characterization and dielectric properties of SnO2 thin films

    Science.gov (United States)

    Yıldırım, M. Ali; Yıldırım, Sümeyra Tuna; Sakar, Emine Fedakar; Ateş, Aytunç

    2014-12-01

    SnO2 thin films have been grown on glass substrates using Successive Ionic Layer Adsorption and Reaction (SILAR) method at room temperature and ambient pressure. The annealing temperature effect on the structural, morphological, optical and electrical properties of SnO2 thin films has been investigated. The X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) studies have showed that all the films have exhibited polycrystalline nature with tetragonal structure and have been covered well on glass substrates. The crystalline and surface properties of the films have improved with increasing annealing temperature. The band gap values have been changed from 3.73 to 3.66 eV depending on the annealing temperature. The refractive index (n), optical static and high frequency dielectric constants (εo, ε∞) values have been calculated as a function of the annealing temperature. The resistivity values of the films have changed between 10-1 - 10-3 Ω cm with annealing temperature and light at room temperature.

  18. 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.

  19. Effect of substrate type, dopant and thermal treatment on physicochemical properties of TiO2–SnO2 sol–gel films

    Indian Academy of Sciences (India)

    I Stambolova; V Blaskov; S Vassilev; M Shipochka; A Loukanov

    2012-08-01

    Thin nanocrystalline TiO2–SnO2 films (0–50 mol% SnO2) were prepared on quartz and stainless steel substrates by sol–gel coating method. The obtained films were investigated by XRD, Raman spectroscopy and XPS. The size of the nanocrystallites was determined by XRD–LB measurements. We ascertained that the increase of treatment temperature and concentration of SnO2 in the films favour the crystallization of rutile phase. The substrate type influences more substantially the phase composition of the TiO2–SnO2 films. It was established that a penetration of elements took place fromthe substrate into the films. TiO2 films deposited on quartz substrate include a Si which stabilizes anatase phase up to 600 °C. The films which are deposited on stainless steel substrate and treated at 700 °C show the presence of significant quantity of rutile phase. This phenomenon could be explained by the combined effect of Sn dopant as well as Fe and Cr, which also are penetrated in the films from the steel substrate. The titania films doped up to 10 mol% SnO2 on stainless steel possess only 12–17 nm anatase crystallites, whereas the TiO2–(10–50 mol%) SnO2 films contain very fine grain rutile phase (4 nm).

  20. Texture-Etched SnO2 Glasses Applied to Silicon Thin-Film Solar Cells

    Directory of Open Access Journals (Sweden)

    Bing-Rui Wu

    2014-01-01

    Full Text Available Transparent electrodes of tin dioxide (SnO2 on glasses were further wet-etched in the diluted HCl:Cr solution to obtain larger surface roughness and better light-scattering characteristic for thin-film solar cell applications. The process parameters in terms of HCl/Cr mixture ratio, etching temperature, and etching time have been investigated. After etching process, the surface roughness, transmission haze, and sheet resistance of SnO2 glasses were measured. It was found that the etching rate was increased with the additions in etchant concentration of Cr and etching temperature. The optimum texture-etching parameters were 0.15 wt.% Cr in 49% HCl, temperature of 90°C, and time of 30 sec. Moreover, silicon thin-film solar cells with the p-i-n structure were fabricated on the textured SnO2 glasses using hot-wire chemical vapor deposition. By optimizing the texture-etching process, the cell efficiency was increased from 4.04% to 4.39%, resulting from the increment of short-circuit current density from 14.14 to 15.58 mA/cm2. This improvement in cell performances can be ascribed to the light-scattering effect induced by surface texturization of SnO2.

  1. 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.

  2. 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.

  3. 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.

  4. Preparation and Characterization of Nano-Structured SiO2 Thin Films on Carbon Steel

    Institute of Scientific and Technical Information of China (English)

    Rong Chun XIONG; Dong Zhou YAN; Gang WEI

    2003-01-01

    Nano-structured SiO2 thin films were prepared on the surface of carbon steel for the first time by LPD. The compositions of the films were analyzed by XPS, and the surface morphology of the thin films were observed by AFM. The thin films were constituted by compact particles of SiO2, and there was no Fe in the films. In the process of film forming, the SiO2 colloid particles were deposited or absorbed directly onto the surface of carbon steel substrates that were activated by acid solution containing inhibitor, and corrosion of the substrates was avoided. The nano-structured SiO2 thin films that were prepared had excellent protective efficiency to the carbon steel.

  5. Photoelectrocatalytic activity of two antimony doped SnO2 films for oxidation of phenol pollutants

    Institute of Scientific and Technical Information of China (English)

    WANG Yan; FAN Cai-mei; HUA Bo; LIANG Zhen-hai; SUN Yan-pin

    2009-01-01

    Two types of Sb-doped SnO2 films on titanium substrate were prepared by the combination of electro-deposition and dip-coating (Ti/SnO2-Sb2O4/SnO2-Sb2O4) and single dip-coating (Ti/SnO2-Sb2O4), respectively. The surface morphology and crystalline structure of both film electrodes were characterized using X-ray diffractometry(XRD) and scanning electron microscopy(SEM). XRD spectra indicate that the rutile SnO2 forms in two films and a TiO2 crystallite exists only in Ti/SnO2-Sb2O4 electrode. SEM images show that the surface morphology of two films is typically cracked-mud structure. The photooxidation experiment was proceeded to further confirm the two electrode activity. The results show that the photoelectrocatalytic degradation efficiency of Ti/SnO2-Sb2O4 electrode with sub-layer is higher than that of simple Ti/SnO2-Sb2O4 electrode using phenol as a model organic pollutant. The Ti/SnO2-Sb2O4/SnO2-Sb2O4 photoanode has a better photoelectrochemical performance than Ti/SnO2-Sb2O4 photoanode for the removal of organic pollutants from water.

  6. CdS/CdSe Co-sensitized Solar Cells Based on Hierarchically Structured SnO2/TiO2 Hybrid Films

    Science.gov (United States)

    Chen, Zeng; Wei, Chaochao; Li, Shengjun; Diao, Chunli; Li, Wei; Kong, Wenping; Zhang, Zhenlong; Zhang, Weifeng

    2016-06-01

    SnO2 nanosheet-structured films were prepared on a fluorine-doped tin oxide (FTO) substrate using ZnO nanosheet as template. The as-prepared SnO2 nanosheets contained plenty of nano-voids and were generally vertical to the substrate. TiO2 nanoparticles were homogeneously deposited into the intervals between the SnO2 nanosheets to prepare a hierarchically structured SnO2/TiO2 hybrid film. The hybrid films were co-sensitized with CdS and CdSe quantum dots. The sensitized solar cells assembled with the SnO2/TiO2 hybrid film showed much higher photoelectricity conversion efficiency than the cells assembled with pure TiO2 films. The lifetime of photoinduced electron was also investigated through electrochemical impedance spectroscopy, which showed that the SnO2/TiO2 hybrid film electrode is as long as the TiO2 film electrode.

  7. CdS/CdSe Co-sensitized Solar Cells Based on Hierarchically Structured SnO2/TiO2 Hybrid Films.

    Science.gov (United States)

    Chen, Zeng; Wei, Chaochao; Li, Shengjun; Diao, Chunli; Li, Wei; Kong, Wenping; Zhang, Zhenlong; Zhang, Weifeng

    2016-12-01

    SnO2 nanosheet-structured films were prepared on a fluorine-doped tin oxide (FTO) substrate using ZnO nanosheet as template. The as-prepared SnO2 nanosheets contained plenty of nano-voids and were generally vertical to the substrate. TiO2 nanoparticles were homogeneously deposited into the intervals between the SnO2 nanosheets to prepare a hierarchically structured SnO2/TiO2 hybrid film. The hybrid films were co-sensitized with CdS and CdSe quantum dots. The sensitized solar cells assembled with the SnO2/TiO2 hybrid film showed much higher photoelectricity conversion efficiency than the cells assembled with pure TiO2 films. The lifetime of photoinduced electron was also investigated through electrochemical impedance spectroscopy, which showed that the SnO2/TiO2 hybrid film electrode is as long as the TiO2 film electrode.

  8. Water droplet behavior on superhydrophobic SiO2 nanocomposite films during icing/deicing cycles

    NARCIS (Netherlands)

    Lazauskas, A.; Guobiene, A.; Prosycevas, I.; Baltrusaitis, V.; Grigaliunas, V.; Narmontas, P.; Baltrusaitis, Jonas

    2013-01-01

    This work investigates water droplet behavior on superhydrophobic (water contact angle value of 162 ± 1°) SiO2 nanocomposite films subjected to repetitive icing/deicing treatments, changes in SiO2 nanocomposite film surface morphology and their non-wetting characteristics. During the experiment, wat

  9. 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

  10. Water droplet behavior on superhydrophobic SiO2 nanocomposite films during icing/deicing cycles

    NARCIS (Netherlands)

    Lazauskas, A.; Guobiene, A.; Prosycevas, I.; Baltrusaitis, V.; Grigaliunas, V.; Narmontas, P.; Baltrusaitis, J.

    2013-01-01

    This work investigates water droplet behavior on superhydrophobic (water contact angle value of 162 ± 1°) SiO2 nanocomposite films subjected to repetitive icing/deicing treatments, changes in SiO2 nanocomposite film surface morphology and their non-wetting characteristics. During the experiment, wat

  11. Water droplet behavior on superhydrophobic SiO2 nanocomposite films during icing/deicing cycles

    NARCIS (Netherlands)

    Lazauskas, A.; Guobiene, A.; Prosycevas, I.; Baltrusaitis, V.; Grigaliunas, V.; Narmontas, P.; Baltrusaitis, Jonas

    2013-01-01

    This work investigates water droplet behavior on superhydrophobic (water contact angle value of 162 ± 1°) SiO2 nanocomposite films subjected to repetitive icing/deicing treatments, changes in SiO2 nanocomposite film surface morphology and their non-wetting characteristics. During the experiment,

  12. Facile Synthesis of Novel Nanostructured MnO2Thin Films and Their Application in Supercapacitors

    Directory of Open Access Journals (Sweden)

    Xia H

    2009-01-01

    Full Text Available Abstract Nanostructured α-MnO2thin films with different morphologies are grown on the platinum substrates by a facile solution method without any assistance of template or surfactant. Microstructural characterization reveals that morphology evolution from dandelion-like spheres to nanoflakes of the as-grown MnO2is controlled by synthesis temperature. The capacitive behavior of the MnO2thin films with different morphologies are studied by cyclic voltammetry. The α-MnO2thin films composed of dandelion-like spheres exhibit high specific capacitance, good rate capability, and excellent long-term cycling stability.

  13. Transport and electroluminescence mechanism in Au/(Si/SiO2)/P-Si film

    Institute of Scientific and Technical Information of China (English)

    ZHANG Kai-biao; MA Shu-yi; MA Zi-jun; CHEN Hai-xia

    2006-01-01

    The samples of Au/(Si/SiO2)/p-Si structure were fabricated by using the R.F magnetron sputtering technique.Its carrier transport and electroluminescence mechanism were studied from the I-V curves and EL spectra by using the Configuration Coordinate as a theoretical model.The result indicates that there are two defect centers in SiO2 films.The electron in Au and the hole in p-Si went into SiO2 film by the Fowler-Nordheim tunneling model at a high bias voltage and recombined through these defect centers in SiO2 film.

  14. TiO2/SiO2 porous composite thin films: Role of TiO2 areal loading and modification with gold nanospheres on the photocatalytic activity

    Science.gov (United States)

    Levchuk, Irina; Sillanpää, Mika; Guillard, Chantal; Gregori, Damia; Chateau, Denis; Parola, Stephane

    2016-10-01

    The aim of the work was to study photocatalytic activity of composite TiO2/Au/SiO2 thin films. Coatings were prepared using sol-gel technique. Physicochemical parameters of coatings were characterized using UV-vis spectrometry, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectrometry (XPS), inductively coupled plasma optical emission spectroscopy (ICP-OES), ellipsometry, tactile measurements, goniometry and diffuse reflectance measurements. The photocatalytic activity of the films was tested in batch mode using aqueous solution of formic acid. Changes of formic acid concentration were determined by means of high pressure liquid chromatography (HPLC). Increase of initial degradation rate of formic acid was detected for TiO2/Au/SiO2 films with gold nanoparticle's load 0.5 wt.% and 1.25 wt.%. However, deeper insights using more detailed characterization of these coatings demonstrated that the improvement of the photocatalytic activity is more probably attributed to an increase in the areal loading of TiO2.

  15. Violet/blue photoluminescence from CeO2 thin film

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    CeO2 thin film was fabricated by dual ion beam epitaxial technique. The violet/blue PL at room temperature and lower temperature was observed from the CeO2 thin film. After the analysis of crystal structure and valence in the compound was carried out by the XRD and XPS technique, it was inferred that the origin of CeO2 PL was due to the electrons transition from Ce4f band to O2p band and the defect level to O2p band. And these defects levels were located in the range of 1 eV around Ce4f band.

  16. 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.

  17. 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.

  18. Structural and morphological characterization of TiO2-SnO2 thin film prepared by combining doctor-blade and sol-gel techniques

    Science.gov (United States)

    Adawiyah, S. R.; Endarko

    2017-04-01

    The TiO2-SnO2 thin film has successfully been synthesized using the co-precipitation method and was coated on ITO (Indium Tin Oxide) substrate by doctor-blade technique. The structure and morphology of the film were investigated by XRD and SEM, respectively. The results showed that the film with SnO2 has a stronger formation of anatase phase compared to TiO2 film. The morphological study is also revealed that the TiO2-SnO2 film has a more porous nature and uniform particle aggregates, and the presence of SnO2 has been confirmed with EDX spectra.

  19. All-nano-TiO2 compact film for high-performance dye-sensitized solar cells.

    Science.gov (United States)

    Zanoni, Kassio P S; Amaral, Ronaldo C; Murakami Iha, Neyde Y

    2014-07-09

    An innovative all-nano-TiO2 thin film capable of enhancing dye-sensitized solar cell (DSC) photoefficiencies was prepared by a layer-by-layer method beneath the meso-TiO2 film, employing acid and basic nano-TiO2 sols as cations and anions, respectively. TiO2 syntheses were performed under absolute control to lead to appropriate morphological and optical properties to yield high-quality compact films using profilometry, tuning, and scanning electron microscopy. A detailed study by photoelectrochemical parameters, incident photon-to-current efficiency, electron lifetime, and electrochemical impedance spectroscopy demonstrates that the physical contact between FTO and the electrolyte is prevented and the role of the compact film has been elucidated. DSCs with TiO2 bilayers on top of FTO improved the conversion efficiency up to 62%, mainly because of the prevention of FTO/I3(-) charge recombination and an improved contact between FTO and TiO2.

  20. Cu掺杂SnO2/TiO2复合薄膜的制备及性能研究%Preparation and Properties of Cu-doped SnO2/TiO2 Film

    Institute of Scientific and Technical Information of China (English)

    王国栋; 魏长平; 何瑞英; 伞靖; 彭春佳

    2015-01-01

    制备Cu掺杂的纳米SnO2/TiO2溶胶,采用旋涂法在载玻片上镀膜,经干燥、煅烧制得Cu掺杂的SnO2/TiO2薄膜,通过对比实验探讨掺杂比例、条件、复合形式等对结构和性能的影响。采用XRD、SEM、EDS、UV-Vis等测试手段对样品进行表征,并以甲基橙为探针考察了其光催化降解性能。 XRD测试结果显示薄膜的晶型为锐钛矿型,结晶度较高。 SEM谱图显示薄膜表面无明显开裂,粒子分布均匀,粒径约为20 nm。 EDS测试结果表明薄膜材料中含有Cu元素,谱形一致。 UV-Vis吸收光谱表明Cu掺杂以及SnO2/TiO2的复合使得在近紫外区的光吸收比纯TiO2明显增强。光催化实验表明Cu掺杂后使得SnO2/TiO2复合薄膜对甲基橙的光催化降解效率进一步提高,SnO2/TiO2复合薄膜的光催化活性在10%Cu掺杂时达到最高。%Cu-doped nano-SnO2 TiO2 gelatins were prepared and coated onto glass substrates by spin coating method, followed by drying at low temperature and calcined at high temperature. The films were characterized by XRD, SEM, EDS, and UV-Vis. The photocatalysis degradation efficiency was studied by using methyl orange as probe. XRD patterns show that the films are anatase structure. SEM images show that the surfaces of the films are flat without obvious crack, and the average diam-eter is about 20 nm. EDS results indicate that Cu has been introduced to SnO2/TiO2 films. UV-Vis absorption spectra show that the absorbance of Cu-doped SnO2/TiO2 films at visible region increase comparing to pure TiO2 film. The degradation experiment under UV light shows that the photocataly-sis degradation efficiency of Cu-doped SnO2/TiO2 film is higher than that of pure TiO2 film. The photocatalysis degradation efficiency is the biggest when the doping mole fraction of Cu is 10%.

  1. Improved performance of dye-sensitized solar cells using TiO2 nanotubes infiltrated by TiO2 nanoparticles using a dipping-rinsing-hydrolysis process

    Science.gov (United States)

    Lin, Lu-Yin; Chen, Chia-Yuan; Yeh, Min-Hsin; Tsai, Keng-Wei; Lee, Chuan-Pei; Vittal, R.; Wu, Chun-Guey; Ho, Kuo-Chuan

    2013-12-01

    An efficient back-illuminated dye-sensitized solar cell (DSSC) is made with a flexible Ti-foil based photoanode composed of a composite TiO2 film with TiO2 nanotubes (TNT) and TiO2 nanoparticles (TNP). The composite TiO2 film is fabricated through a novel dipping-rinsing-hydrolysis (DRH) process by inserting TiO2 into TNT and sintering the product to form TNP inside TNT. By directly placing TiO2 nanoparticles into TNT, the former grow internally from the base of TNT to occupy it completely. This solves previous problems of incomplete filling of TNP into TNT, which used partial penetration of TiCl4 reactant from the top of the TNT. In the present case, the TNP are grown from the base of TNT. A DSSC containing TNT and TNP prepared in this way shows a photoelectric efficiency of 6.45%, which is much higher than that (4.21%) of a DSSC with untreated TNT. The films are characterized by using scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. The improvement in the photoelectric efficiency is explained by using electrochemical impedance spectroscopy (EIS), incident photon-to-current conversion efficiency (IPCE) analysis, and UV-absorption spectra analysis.

  2. Nanocrystalline SnO2:F Thin Films for Liquid Petroleum Gas Sensors

    OpenAIRE

    Sutichai Chaisitsak

    2011-01-01

    This paper reports the improvement in the sensing performance of nanocrystalline SnO2-based liquid petroleum gas (LPG) sensors by doping with fluorine (F). Un-doped and F-doped tin oxide films were prepared on glass substrates by the dip-coating technique using a layer-by-layer deposition cycle (alternating between dip-coating a thin layer followed by a drying in air after each new layer). The results showed that this technique is superior to the conventional technique for both improving the ...

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Optical and water repellant properties of Ag/SnO2 bilayer thin films

    Directory of Open Access Journals (Sweden)

    Ravipati Praveena

    2016-02-01

    Full Text Available The optical and water repellant properties of single layer and bilayer films of Ag and SnO2 deposited on glass substrates by thermal evaporation have been reported. Ag/SnO2 bilayers were deposited in two sequences wherein the deposition of SnO2 layer was followed by Ag deposition and vice versa. X-ray diffraction studies show that the Ag films crystallize in the FCC structure and SnO2 is amorphous, while atomic force microscopy images indicate the formation of large clusters of the order of 12 nm. The single layer Ag films exhibit localized surface plasmon resonance (LSPR that shifts from visible region to the infrared with increase in thickness from 5 to 12 nm. It is observed that, only the Ag films of thickness ≤ 8 nm exhibits LSPR peak whereas the critical thickness is 5 nm for Ag/SnO2 films. A blue shift is observed in the LSPR peak position when the SnO2 layer caps the Ag film. Whereas, the LSPR of Ag is suppressed significantly when the SnO2 layer is introduced between the glass and the Ag film and also when Ag and SnO2 were co-evaporated. Water repellant properties indicate that the pure Ag film has an average contact angle of 104o which decreases to 100o when SnO2 caps the Ag layer and 97o when Ag is deposited on top of the SnO2 buffer layer. Co-evaporated Ag-SnO2 films show a contact angle of 93o.

  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. 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.

  11. Electrochemical and fluorescence properties of SnO2 thin films and its antibacterial activity.

    Science.gov (United States)

    Henry, J; Mohanraj, K; Sivakumar, G; Umamaheswari, S

    2015-05-15

    Nanocrystalline SnO2 thin films were deposited by a simple and inexpensive sol-gel spin coating technique and the films were annealed at two different temperatures (350°C and 450°C). Structural, vibrational, optical and electrochemical properties of the films were analyzed using XRD, FTIR, UV-Visible, fluorescence and cyclic voltammetry techniques respectively and their results are discussed in detail. The antimicrobial properties of SnO2 thin films were investigated by agar agar method and the results confirm the antibacterial activity of SnO2 against Escherichiacoli and Bacillus.

  12. 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.

  13. Hydrothermal Etching Treatment to Rutile TiO2 Nanorod Arrays for Improving the Efficiency of CdS-Sensitized TiO2 Solar Cells.

    Science.gov (United States)

    Wan, Jingshu; Liu, Rong; Tong, Yuzhu; Chen, Shuhuang; Hu, Yunxia; Wang, Baoyuan; Xu, Yang; Wang, Hao

    2016-12-01

    Highly ordered TiO2 nanorod arrays (NRAs) were directly grown on an F:SnO2 (FTO) substrate without any seed layer by hydrothermal route. For a larger surface area, the second-step hydrothermal treatment in hydrochloric acid was carried out to the as-prepared TiO2 NRAs. The results showed that the center portion of the TiO2 nanorods were dissolved in the etching solution to form a nanocave at the initial etching process. As the etching time extended, the tip parts of the nanocave wall split into lots of nanowires with a reduced diameter, giving rise to a remarkable increase of specific surface area for the TiO2 NRAs. The TiO2 films after etching treatment were sensitized by CdS quantum dots (QDs) to fabricate quantum dot-sensitized solar cells (QDSSCs), which exhibited a significant improvement in the photocurrent density in comparison with that of the un-treated device, this mainly attributed to the enhancement of QD loading and diffused reflectance ability. Through modifying the etching TiO2 films with TiCl4, a relatively high power conversion efficiency (PCE) of 3.14 % was obtained after optimizing the etching time.

  14. 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.

  15. 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.

  16. 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.

  17. Synthesis of mesoporous TiO2/SiO2 hybrid films as an efficient photocatalyst by polymeric micelle assembly.

    Science.gov (United States)

    Li, Yunqi; Bastakoti, Bishnu Prasad; Imura, Masataka; Hwang, Soo Min; Sun, Ziqi; Kim, Jung Ho; Dou, Shi Xue; Yamauchi, Yusuke

    2014-05-12

    Thermally stable mesoporous TiO2/SiO2 hybrid films with pore size of 50 nm have been synthesized by adopting the polymeric micelle-assembly method. A triblock copolymer, poly(styrene-b-2-vinyl pyridine-b-ethylene oxide), which serves as a template for the mesopores, was utilized to form polymeric micelles. The effective interaction of titanium tetraisopropoxide (TTIP) and tetraethyl orthosilicate (TEOS) with the polymeric micelles enabled us to fabricate stable mesoporous films. By changing the molar ratio of TEOS and TTIP, several mesoporous TiO2/SiO2 hybrid films with different compositions can be synthesized. The presence of amorphous SiO2 phase effectively retards the growth of anatase TiO2 crystal in the pore walls and retains the original mesoporous structure, even at higher temperature (650 °C). These TiO2/SiO2 hybrid films are of very high quality, without any cracks or voids. The addition of SiO2 phase to mesoporous TiO2 films not only adsorbs more organic dyes, but also significantly enhances the photocatalytic activity compared to mesoporous pure TiO2 film without SiO2 phase. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Amphiphilic block-graft copolymer templates for organized mesoporous TiO2 films in dye-sensitized solar cells

    Science.gov (United States)

    Lim, Jung Yup; Lee, Chang Soo; Lee, Jung Min; Ahn, Joonmo; Cho, Hyung Hee; Kim, Jong Hak

    2016-01-01

    Amphiphilic block-graft copolymers composed of poly(styrene-b-butadiene-b-styrene) (SBS) backbone and poly(oxyethylene methacrylate) (POEM) side chains are synthesized and combined with hydrophilically preformed TiO2 (Pre-TiO2), which works as a structural binder as well as titania source. This results in the formation of crack free, 6-μm-thick, organized mesoporous TiO2 (OM-TiO2) films via one-step doctor-blading based on self-assembly of SBS-g-POEM as well as preferential interaction of POEM chains with Pre-TiO2. SBS-g-POEM with different numbers of ethylene oxide repeating units, SBS-g-POEM(500) and SBS-g-POEM(950), are used to form OM-TiO2(500) and OM-TiO2(950), respectively. The efficiencies of dye-sensitized solar cells (DSSCs) with a quasi-solid-state polymer electrolyte reach 5.7% and 5.8% at 100 mW/cm2 for OM-TiO2(500) and OM-TiO2(950), respectively. The surface area of OM-TiO2(950) was greater than that of OM-TiO2(500) but the light reflectance was lower in the former, which is responsible for similar efficiency. Both DSSCs exhibit much higher efficiency than one (4.8%) with randomly-organized particulate TiO2 (Ran-TiO2), which is attributed to the higher dye loading, reduced charge recombination and improved pore infiltration of OM-TiO2. When utilizing poly((1-(4-ethenylphenyl)methyl)-3-butyl-imidazolium iodide) (PEBII) and mesoporous TiO2 spheres as the solid electrolyte and the scattering layer, the efficiency increases up to 7.5%, one of the highest values for N719-based solid-state DSSCs.

  19. 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.

  20. Preparation and photocatalytic activity of PANI/TiO2 composite film

    Institute of Scientific and Technical Information of China (English)

    GAO Jinzhang; LI Shengying; YANG Wu; ZHAO Guohu; BO Lili; SONG Li

    2007-01-01

    A PANI/TiO2 composite film deposited on the glass surface was successfully prepared using sol-gel dip-coating technique and chemical oxidation method.The film was characterized using XRD, AFM,and UV.The result showed that the TiO2 film consists of both cuboid-shaped and anatase-phased TiO2 nanoparticles.The average grain size of TiO2 in the film was approximately 20 nm.After coating with PANI,the particle was changed into irregular spherical-shaped and the size was increased up to approximately 35 nm in diameter.UV-Vis spectroscopy analysis indicated that the coating of TiO2 with PANI would result in an enhancement of photocatalytic efficiency and an extension of the photoresponse of TiO2.The band gap of the PANI/TiO2 film was 3.18 eV.The photocatalytic property of the film was evaluated by the degradation of rhodamine-B.It was found that 67.1% and 83.2% of rhodamine-B could be degraded under sunlight and UV irradiation within 120 min using the PANI/TiO2 composite film as photocatalyst.

  1. 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.

  2. Electrochemical Performance of rf Magnetron Sputtered LiCoO2 Thin Film Positive Electrodes

    Science.gov (United States)

    Kumar, P. Jeevan; Babu, K. Jayanth; Hussain, O. M.

    2010-12-01

    Thin films of LiCoO2 were grown by rf magnetron sputtering technique and studied the influence of In situ annealing treatment on microstructural and electrochemical properties of the films. Annealing treatment in presence of O2 ambient develops characteristic (104) plan in relative to (003) plane texture indicating that the films have HT-layered structure with R3¯m symmetry. The effect is discussed in terms of grain size, cycling stability, reversibility and the specific discharge capacity.

  3. Optical and physical properties of solgel-derived GeO2:SiO2 films in photonic applications.

    Science.gov (United States)

    Ho, Charles K F; Pal, Rajni; Djie, H S; Pita, Kantisara; Ngo, Nam Quoc; Osipowicz, T

    2007-07-10

    The functionality of optical components relies heavily on the composition-dependent properties of germanosilicate materials, which include the refractive index, photosensitivity, and microstructural properties. Recent studies and parallel developments are presented of germanosilicate films with composition x of Ge content (i.e., xGeO(2):(1-x)SiO(2)) that were synthesized by the solgel process for various integrated photonic applications undertaken. The following novel aspects are discussed with respect to the effect of composition of the glassy films (0.05properties, UV imprinting of optical waveguides with relatively large index change (Dn), and quantum-well intermixing enhancement observed in InGaAs(P)/InP quantum-well optical devices. The implications of the results are discussed.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Photocatalytic degradation of methyl orange by CeO2 and Fe-doped CeO2 films under visible light irradiation.

    Science.gov (United States)

    Channei, D; Inceesungvorn, B; Wetchakun, N; Ukritnukun, S; Nattestad, A; Chen, J; Phanichphant, S

    2014-08-29

    Undoped CeO2 and 0.50-5.00 mol% Fe-doped CeO2 nanoparticles were prepared by a homogeneous precipitation combined with homogeneous/impreganation method, and applied as photocatalyst films prepared by a doctor blade technique. The superior photocatalytic performances of the Fe-doped CeO2 films, compared with undoped CeO2 films, was ascribed mainly to a decrease in band gap energy and an increase in specific surface area of the material. The presence of Fe(3+) as found from XPS analysis, may act as electron acceptor and/or hole donor, facilitating longer lived charge carrier separation in Fe-doped CeO2 films as confirmed by photoluminescence spectroscopy. The 1.50 mol% Fe-doped CeO2 film was found to be the optimal iron doping concentration for MO degradation in this study.

  9. 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.

  10. 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.

  11. [Spectral analysis of effects of annealing on the characteristics of intrinsic SnO2 polycrystalline thin films].

    Science.gov (United States)

    Zeng, Guang-Gen; Zheng, Jia-Gui; Li, Bing; Chen, Qi; Wu, Li-Li; Li, Wei; Zhang, Jing-Quan; Lei, Zhi; Cai, Ya-Ping; Cai, Wei; Feng, Liang-Huan

    2008-02-01

    In order to improve the conversion efficiency of the CdTe solar cells, it is necessary to decrease the thickness of CdS layer. However, the decrease in CdS thickness may lead to adverse effects on the solar cells. Therefore, a high-resistance transparent layer (intrinsic SnO2) has been used as a buffer layer between the transparent conducting oxide (TCO) and CdS layer. In the present paper, SnO2 polycrystalline thin films were prepared by magnetic reactive sputtering. The properties of the films before and after annealing were studied by XRD and XPS. The results revealed that the films annealed at 550 degrees C for 30 minutesare polycrystalline SnO2 with a single phase of tetragonal structure and have orientation of (110) direction. XPS investigation shows that after annealing the oxygen content of the film increases, O1s peak shifts to lower energies, and SnO is oxidized into SnO2, After annealing the intrinsic SnO2 films of high-resistance as a buffer layer are very suitable for the CdTe solar cells.

  12. Optical properties of ZnO thin films on SiO2 substrates deposited by radio frequency magnetron sputtering

    Institute of Scientific and Technical Information of China (English)

    Deping Xiong(熊德平); Xiqing Zhang(张希清); Jing Wang(王晶); Peng Lin(林鹏); Shihua Huang(黄世华)

    2004-01-01

    The optical properties of both the annealed and as-deposited ZnO thin films by radio frequency (RF)magnetron sputtering on SiO2 substrates were studied. In the annealed films, two pronounced well defined exciton absorption peaks for the A and B excitons were obtained in the absorption spectra, a strong free exciton emission without deep-level emissions was observed in the photoluminescence (PL) spectra at room temperature. It was found that annealing the films in oxygen dramatically improved the optical properties and the quality of the films.

  13. 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.

  14. Bioactivity and cytocompatibility of zirconia (ZrO(2)) films fabricated by cathodic arc deposition.

    Science.gov (United States)

    Liu, Xuanyong; Huang, Anping; Ding, Chuanxian; Chu, Paul K

    2006-07-01

    Zirconium oxide thin films were fabricated on silicon wafers using a filtered cathodic arc system in concert with oxygen plasma. The structure and phase composition of the zirconium oxide thin films were characterized by atomic force microscopy (AFM), X-ray diffraction (XRD), Rutherford backscattering spectrometry (RBS), and transmission electron microscopy (TEM). The bioactivity was assessed by investigating the formation of apatite on the film surface after soaking in simulated body fluids. Bone marrow mesenchymal stem cells (BMMSC) were used to further evaluate the cytocompatibility of the materials. The results indicate that the films are composed of stoichiometric ZrO(2) and the composition is quite uniform throughout the thickness. Bone-like apatite can be formed on the surface of the ZrO(2) thin film in our SBF immersion experiments, suggesting that the surface is bioactive. The outermost layer of the ZrO(2) thin film comprises nano-sized particles that can be identified by AFM images taken on the thin film surface and TEM micrographs obtained from the interface between the ZrO(2) thin film and apatite layer. The nanostructured surface is believed to be the key factor that apatite is induced to precipitate on the surface. Bone marrow mesenchymal stem cells are observed to grow and proliferate in good states on the film surface. Our results show that ZrO(2) thin films fabricated by cathodic arc deposition exhibit favorable bioactivity and cytocompatibility.

  15. 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

  16. Photoemission Spectroscopy Characterization of Attempts to Deposit MoO2 Thin Film

    Directory of Open Access Journals (Sweden)

    Irfan

    2011-01-01

    Full Text Available Attempts to deposit molybdenum dioxide (MoO2 thin films have been described. Electronic structure of films, deposited by thermal evaporation of MoO2 powder, had been investigated with ultraviolet photoemission and X-ray photoemission spectroscopy (UPS and XPS. The thermally evaporated films were found to be similar to the thermally evaporated MoO3 films at the early deposition stage. XPS analysis of MoO2 powder reveals presence of +5 and +6 oxidation states in Mo 3d core level along with +4 state. The residue of MoO2 powder indicates substantial reduction in higher oxidation states while keeping +4 oxidation state almost intact. Interface formation between chloroaluminum phthalocyanine (AlPc-Cl and the thermally evaporated film was also investigated.

  17. 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.

  18. 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.

  19. PLD prepared nanostructured Pt-CeO2 thin films containing ionic platinum

    Science.gov (United States)

    Vorokhta, M.; Khalakhan, I.; Matolínová, I.; Nováková, J.; Haviar, S.; Lančok, J.; Novotný, M.; Yoshikawa, H.; Matolín, V.

    2017-02-01

    The composition of nanostructured Pt-CeO2 films on graphite substrates prepared by pulsed laser deposition has been investigated by means of hard X-ray photoelectron spectroscopy, scanning electron microscopy, high resolution transmission electron microscopy, and atomic force microscopy. The influence of morphology of the graphite substrates was investigated with respect to the relative concentrations of ionic and metallic Pt species in the films. It was found that the degree of Pt2+ enrichment is directly related to the surface morphology of graphite substrates. In particular, the deposition of Pt-CeO2 films on rough graphite substrate etched in oxygen plasma yielded nanostructured Pt-CeO2 catalyst films with high surface area and high Pt2+/Pt0 ratio. The presented results demonstrate that PLD is a suitable method for the preparation of thin Pt-CeO2 catalyst films for fuel cell applications.

  20. 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.

  1. Molecular dynamics simulations of La2O3 thin films on SiO2

    Institute of Scientific and Technical Information of China (English)

    Mou Fang; Stephen P. Kelty; Xiangming He

    2014-01-01

    Classical molecular dynamics is used to investigate the equilibrium state of the surface region and interface of heteroepitaxial La2O3 thin films. Due to the lattice mismatch, heteroepitaxial thin films are subject to very large stress. For this reason the behavior of La2O3 thin films at SiO2 interface becomes an important concern. Our result indicates that La2 O3 can uniformly wet SiO2 surface. The properties of the simulated films are analyzed and the lack of any discernible crystalline phase in epitaxial La2O3 on SiO2 indicates that the lattice mismatch between SiO2 and La2O3 is sufficiently large to prevent the formation of even short-range orders in La2O3 film.

  2. Morphology and Photoelectrochemical Characterization of MEH-PPV/PCBM Composite Film Doped with TiO2 Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    Farid Habelhames; Zerguine Wided; Leila Lamiri; Belkacem Nessark; Hassina Derbal-Habak

    2013-01-01

    Poly[2-methoxy-5-(20-ethylhexyloxy)-p-phenylenevinylene] (MEH-PPV),[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and titanium dioxide (TiO2) nanoparticles (n-type) were dissolved,mixed and deposited by physical methods (spin-coating) on indium tin-oxide (ITO) substrate.The incorporation of the titanium dioxide nanoparticles changed the morphology and increased the roughness of polymers film (MEH-PPV/PCBM),and the photocurrent density of the composite (MEH-PPV/PCBM +n-TiO2) was higher than that of single MEHPPV/PCBM film.The study showed that the presence of n-TiO2 particles in the polymeric film improves the photoelectrochemical properties of MEH-PPV/PCBM composite.

  3. 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.

  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. The Effect of Normal Force on Tribocorrosion Behaviour of Ti-10Zr Alloy and Porous TiO2-ZrO2 Thin Film Electrochemical Formed

    Science.gov (United States)

    Dănăilă, E.; Benea, L.

    2017-06-01

    The tribocorrosion behaviour of Ti-10Zr alloy and porous TiO2-ZrO2 thin film electrochemical formed on Ti-10Zr alloy was evaluated in Fusayama-Mayer artificial saliva solution. Tribocorrosion experiments were performed using a unidirectional pin-on-disc experimental set-up which was mechanically and electrochemically instrumented, under various solicitation conditions. The effect of applied normal force on tribocorrosion performance of the tested materials was determined. Open circuit potential (OCP) measurements performed before, during and after sliding tests were applied in order to determine the tribocorrosion degradation. The applied normal force was found to greatly affect the potential during tribocorrosion experiments, an increase in the normal force inducing a decrease in potential accelerating the depassivation of the materials studied. The results show a decrease in friction coefficient with gradually increasing the normal load. It was proved that the porous TiO2-ZrO2 thin film electrochemical formed on Ti-10Zr alloy lead to an improvement of tribocorrosion resistance compared to non-anodized Ti-10Zr alloy intended for biomedical applications.

  6. 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.

  7. Optical Absorption of Sol-Gel Derived ZnO/TiO2 Nanocomposite Films

    Institute of Scientific and Technical Information of China (English)

    袁志好; 唐成春; 范守善

    2001-01-01

    ZnO/TiO2 nanocomposite films on quartz substrates were prepared by the sol-gel method, and the corresponding optical absorption properties were investigated. In the ultraviolet region, it was found that the position of fundamental absorption edge partially depends on the composition of the ZnO/TiO2 films, and shifts toward a shorter wavelength with the increasing content of ZnO in the films. Moreover, a blueshift of the absorption edge resulted from a quantum size effect and the quantum confinement effect was observed in the ZnO/TiO2 system.

  8. Fabrication and characterization of anatase/rutile–TiO2 thin films by magnetron sputtering: a review

    Directory of Open Access Journals (Sweden)

    Sakae Tanemura, Lei Miao, Wilfried Wunderlich, Masaki Tanemura, Yukimasa Mori, Shoichi Toh and Kenji Kaneko

    2005-01-01

    Full Text Available This review article summarizes briefly some important achievements of our recent reserach on anatase and/or rutile TiO2 thin films, fabricated by helicon RF magnetron sputtering, with good crystal quality and high density, and gives the-state-of-the-art of the knowledge on systematic interrelationship for fabrication conditions, crystal structure, composition, optical properties, and bactericidal abilities, and on the effective surface treatment to improve the optical reactivity of the obtained films.

  9. Optical absorption properties of SnO2 and ZnO co-doped TiO2 film%SnO2和ZnO共掺杂对TiO2薄膜吸光性能的影响

    Institute of Scientific and Technical Information of China (English)

    高延敏; 杨志磊; 吕伟刚; 陶正章

    2013-01-01

    The wide forbidden band gap has affected the development of TiO2 semiconductor materials, which leads to low utilization of solar energy. By co-doping Sn and Zn elements, the light absorption properties of TiO2 thin film will be improved effectively. The experiment scheme about the optimal sol-gel is put forward according to orthogonal design. The best anatase TiO2 thin film was prepared at the element molar ratio 1. 0= 1. 5:10 of tin, zinc and titanium, with the pH value 2. Compared with pure TiO2, co-doped TiO2 had 85nm red shift and declined its band gap. Under the circumtance that SnO2 and ZnO have no effect on TiO2 structure, XRD and SEM analysis showed that changing the way of crystallization, graining refinement and changing morphology features and so on, would improve the light absorption properties of SnO2 and ZnO co-doped TiO2 thin film.%纳米TiO2半导体材料因为禁带隙较宽而存在对太阳能的利用率较低的问题一直影响自身发展.文中研究了不同掺杂组份和制备条件对TiO2薄膜光吸收性能的影响.首先通过正交实验设计出最优溶胶-凝胶实验方案,锡、锌、钛的元素摩尔比为1.0∶0.5:10,pH值为2,制备出锐钛矿型TiO2薄膜.XRD和SEM分析表明SnO2,ZnO掺杂处理使TiO2的光吸收范围从紫外红移到可见光附近,降低其禁带宽度.在不改变TiO2晶型结构的情况下,通过改善TiO2结晶,细化晶粒,改变形貌特征等方式提高TiO2薄膜光吸收性能.

  10. 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.

  11. 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.

  12. Enhancement of room temperature ferromagnetic behavior of rf sputtered Ni-CeO2 thin films

    Science.gov (United States)

    Murugan, R.; Vijayaprasath, G.; Mahalingam, T.; Ravi, G.

    2016-12-01

    Ni-doped CeO2 thin films were prepared under Ar+ atmosphere on glass substrates using rf magnetron sputtering. To assess the properties of the prepared thin films, the influence of various amounts of Ni dopant on structural, morphological, optical, vibrational, compositional and magnetic properties of the CeO2 films were studied by using X-Ray diffraction (XRD), atomic force microscope (AFM), photoluminescence (PL), micro-Raman, X-ray photoelectron spectroscopy (XPS) and vibrating sample magnetometer (VSM). XRD patterns for all the samples revealed the expected CeO2 cubic fluorite-type structure and Ni ions were uniformly distributed in the samples. AFM images of the prepared samples indicate high dense, columnar structure with uniform distribution of CeO2. Room-temperature photoluminescence (PL) and micro-Raman spectroscopic studies revealed an increase of oxygen vacancies with higher concentration of Ni in CeO2. XPS results confirm the presence of Ni2p, O1s and Ce and depict that cerium is present as both Ce4+ and Ce3+ oxidation states in Ce1-xNixO2 (x = 15%) thin film. Field dependent magnetization measurements revealed a paramagnetic behavior for pure CeO2, while a ferromagnetic behavior appeared when Ni is doped in CeO2 films. Doping dependent magnetization measurements suggest that the observed ferromagnetism is due to the presence of metallic Ni clusters with nanometric size and broad size distribution.

  13. 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.

  14. 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.

  15. Photocatalytic degradation of contaminants of concern with composite NF-TiO2 films under visible and solar light.

    Science.gov (United States)

    Barndõk, H; Peláez, M; Han, C; Platten, W E; Campo, P; Hermosilla, D; Blanco, A; Dionysiou, D D

    2013-06-01

    This study reports the synthesis and characterization of composite nitrogen and fluorine co-doped titanium dioxide (NF-TiO(2)) for the removal of contaminants of concern in wastewater under visible and solar light. Monodisperse anatase TiO(2) nanoparticles of different sizes and Evonik P25 were assembled to immobilized NF-TiO(2) by direct incorporation into the sol-gel or by the layer-by-layer technique. The composite films were characterized with X-ray diffraction, high-resolution transmission electron microscopy, environmental scanning electron microscopy, and porosimetry analysis. The photocatalytic degradation of atrazine, carbamazepine, and caffeine was evaluated in a synthetic water solution and in an effluent from a hybrid biological concentrator reactor (BCR). Minor aggregation and improved distribution of monodisperse titania particles was obtained with NF-TiO(2)-monodisperse (10 and 50 nm) from the layer-by-layer technique than with NF-TiO(2) +monodisperse TiO(2) (300 nm) directly incorporated into the sol. The photocatalysts synthesized with the layer-by-layer method achieved significantly higher degradation rates in contrast with NF-TiO(2)-monodisperse titania (300 nm) and slightly faster values when compared with NF-TiO(2)-P25. Using NF-TiO(2) layer-by-layer with monodisperse TiO(2) (50 nm) under solar light irradiation, the respective degradation rates in synthetic water and BCR effluent were 14.6 and 9.5 × 10(-3) min(-1) for caffeine, 12.5 and 9.0 × 10(-3) min(-1) for carbamazepine, and 10.9 and 5.8 × 10(-3) min(-1) for atrazine. These results suggest that the layer-by-layer technique is a promising method for the synthesis of composite TiO(2)-based films compared to the direct addition of nanoparticles into the sol.

  16. Magnetic and Optical Properties of the TiO2-Co-TiO2 Composite Films Grown by Magnetron Sputtering

    Institute of Scientific and Technical Information of China (English)

    LIU Fa-min; DING Peng; SHI Wei-mei; WANG Tian-min

    2007-01-01

    The TiO2-Co-TiO2 sandwich films were successfully grown on glass and silicon substrata making alternate use of radio frequency reactive magnetron sputtering and direct current magnetron sputtering. The structures and properties of these films were identified with X-ray diffraction (XRD), Raman spectra and X-ray photoemission spectra (XPS). It is shown that the sandwich film consists of two anatase TiO2 films with an embedded Co nano-film. The fact that, when the Co nano-film thickens, varied red shifts appear in optical absorption spectra may well be explained by the quantum confinement and tunnel effects. As for magnetic properties, the saturation magnetization, remnant magnetic induction and coercivity vary with the thickness of the Co nano-films. Moreover, the Co nano-film has a critical thickness of about 8.6 nm, which makes the coercivity of the composite film reach the maximum of about 1413 Oe.

  17. Photoelectrocatalytic Degradation of Organic Pollutants in Aqueous Solution Using a Pt-TiO2 Film

    Directory of Open Access Journals (Sweden)

    Chun He

    2009-01-01

    Full Text Available A series of Pt-TiO2 films with nanocrystaline structure was prepared by a procedure of photodeposition and subsequent dip-coating. The Pt-TiO2 films were characterized by X-ray diffraction, scanning electronic microscope, electrochemical characterization to examine the surface structure, chemical composition, and the photoelectrochemical properties. The photocatalytic activity of the Pt-TiO2 films was evaluated in the photocatalytic (PC and photoelectrocatalytic (PEC degradation of formic acid in aqueous solution. Compared with a TiO2 film, the efficiency of formic acid degradation using the Pt-TiO2 films was significantly higher in both the PC and PEC processes. The enhancement is attributed to the action of Pt deposits on the TiO2 surface, which play a key role by attracting conduction band photoelectrons. In the PEC process, the anodic bias externally applied on the illuminated Pt-TiO2 films can further drive away the accumulated photoelectrons from the metal deposits and promote a process of interfacial charge transfer.

  18. Lasting antibacterial activities of Ag-TiO2/Ag/a-TiO2 nanocomposite thin film photocatalysts under solar light irradiation.

    Science.gov (United States)

    Akhavan, O

    2009-08-01

    Photodegradation of Escherichia coli bacteria in presence of Ag-TiO(2)/Ag/a-TiO(2) nanocomposite film with an effective storage of silver nanoparticles was investigated in the visible and the solar light irradiations. The nanocomposite film was synthesized by sol-gel deposition of 30 nm Ag-TiO(2) layer on approximately 200 nm anatase(a-)TiO(2) film previously doped by silver nanoparticles. Both Ag/a-TiO(2) and Ag-TiO(2)/Ag/a-TiO(2) films were transparent with a SPR absorption band at 412 nm. Depth profile X-ray photoelectron spectroscopy showed metallic silver nanoparticles with diameter of 30 nm and fcc crystalline structure were self-accumulated on the film surface at depth of 5 nm of the TiO(2) layer and also at the interface of the Ag-TiO(2) and a-TiO(2) films (at depth of 30 nm). Both OH(-) bounds and H(2)O contents were concentrated on the film surface and at the interface, as a profit in releasing more ionic (not metallic) silver nanoparticles. Antibacterial activity of the nanocomposite film against E. coli bacteria was 5.1 times stronger than activity of the a-TiO(2), in dark. Photo-antibacterial activity of the nanocomposite film exposed by the solar light was measured 1.35 and 6.90 times better than activity of the Ag/a-TiO(2) and a-TiO(2), respectively. The main mechanism for silver ion releasing was inter-diffusion of water and silver nanoparticles through pores of the TiO(2) layer. Durability of the nanocomposite film was at least 11 times higher than the Ag/a-TiO(2) film. Therefore, the Ag-TiO(2)/Ag/a-TiO(2) photocatalyst can be nominated as one of the effective and long-lasting antibacterial nanocomposite materials.

  19. Thin films of SiO2 and hydroxyapatite on titanium deposited by spray pyrolysis.

    Science.gov (United States)

    Jokanovic, V; Jokanovic, B; Izvonar, D; Dacic, B

    2008-05-01

    Wet spray pyrolysis of fine, well-dispersed a SiO2 sol was used for the deposition of thin films of silicon dioxide. The sol was obtained by hydrothermal precipitation of silicon acid from a solution at pH = 10. The morphology, roughness, phase composition, chemical homogeneity and the mechanism of the films were investigated by SEM, EDS and IR spectroscopy. The obtained results show a complete covering of the titanium substrate with SiO2 after 3 h of deposition. It was observed that the film thickness increased from 3 to 19 microm, the roughness of the film decreased from 12 to 3 microm, while the morphology of the deposit changed considerably. A hydroxyapatite film was prepared on the so-obtained SiO2 thin film by spray pyrolysis deposition and its morphology and phase composition were investigated.

  20. 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.

  1. Cellulose Acetate/N-TiO2 Biocomposite Flexible Films with Enhanced Solar Photochromic Properties

    Science.gov (United States)

    Radhika, T.; Anju, K. R.; Silpa, M. S.; Ramalingam, R. Jothi; Al-Lohedan, Hamad A.

    2017-07-01

    Flexible cellulose acetate/N-TiO2 nanocomposite films containing various concentrations of nanosized N-TiO2 and an intelligent methylene blue ink have been prepared by solution casting. The hydrothermally prepared nitrogen-doped titania (N-TiO2) and the films were characterized in detail. The photochromic properties of the prepared films were investigated under ultraviolet (UV), visible light, and simulated solar irradiation by UV-Vis spectrophotometry. Upon irradiation, the films exhibited rapid photochromic response that was reversible at room temperature. Films with higher content of nano N-TiO2 showed enhanced decoloration/recoloration under all irradiation conditions, with fast decoloration/recoloration under simulated solar irradiation. These results suggest that the amount of nano N-TiO2 in the composite, the concentration of methylene blue, and the solvent greatly influence the photochromic properties of the films. Such flexible and transparent cellulose acetate/N-TiO2 films with enhanced decoloration/recoloration properties under solar irradiation are promising smart materials for use in photoreversible printed electronics applications.

  2. Effective Carbon Dioxide Photoreduction over Metals (Fe-, Co-, Ni-, and Cu- Incorporated TiO2/Basalt Fiber Films

    Directory of Open Access Journals (Sweden)

    Jeong Yeon Do

    2016-01-01

    Full Text Available Mineralogical basalt fibers as a complementary adsorbent were introduced to improve the adsorption of CO2 over the surfaces of photocatalysts. TiO2 photocatalysts (M-TiO2 incorporated with 5.0 mol.% 3d-transition metals (Fe, Co, Ni, and Cu were prepared using a solvothermal method and mixed with basalt fibers for applications to CO2 photoreduction. The resulting 5.0 mol.% M-TiO2 powders were characterized by X-ray diffraction, scanning electron microscopy, ultraviolet-visible spectroscopy, photoluminescence, Brunauer, Emmett, and Teller surface area, and CO2-temperature-programmed desorption. A paste composed of two materials was coated and fixed on a Pyrex plate by a thermal treatment. The 5.0 mol.% M-TiO2/basalt fiber films increased the adsorption of CO2 significantly, indicating superior photocatalytic behavior compared to pure TiO2 and basalt fiber films, and produced 158~360 μmol gcat-1 L−1 CH4 gases after an 8 h reaction. In particular, the best performance was observed over the 5.0 mol.% Co-TiO2/basalt fiber film. These results were attributed to the effective CO2 gas adsorption and inhibition of photogenerated electron-hole pair recombination.

  3. Effect of DC glow discharge plasma treatment on PET/TiO(2) thin film surfaces for enhancement of bioactivity.

    Science.gov (United States)

    Navaneetha Pandiyaraj, K; Selvarajan, V; Rhee, Young Ha; Kim, Hyoung Woo; Pavese, Matteo

    2010-08-01

    In this paper, the surfaces of PET/TiO(2) thin film were modified by DC glow discharge plasma as a function of discharge potentials for improving the bioactivity. The hydrophilicity of the plasma-treated PET/TiO(2) film was measured by contact angle measurement and the surface energy was estimated by using Fowkes method. The structural and chemical composition of the plasma-treated PET/TiO(2) was analysed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Immersion in a simulated body solution (SBF) solution was used to evaluate the bioactivity of the plasma-treated PET/TiO(2) samples in vitro. It was found that the plasma treatment modified the surfaces both in chemical composition and crystallinity which makes surface of the PET/TiO(2) to become more hydrophilic compared with untreated one. Analytical and microstructural investigations of SBF results, showed considerable higher rates of apatite formation on the plasma-treated PET/TiO(2) compared to the untreated films.

  4. Highly transparent and flexible bio-based polyimide/TiO2 and ZrO2 hybrid films with tunable refractive index, Abbe number, and memory properties

    Science.gov (United States)

    Huang, Tzu-Tien; Tsai, Chia-Liang; Tateyama, Seiji; Kaneko, Tatsuo; Liou, Guey-Sheng

    2016-06-01

    The novel bio-based polyimide (4ATA-PI) and the corresponding PI hybrids of TiO2 or ZrO2 with excellent optical properties and thermal stability have been prepared successfully. The highly transparent 4ATA-PI containing carboxylic acid groups in the backbone could provide reaction sites for organic-inorganic bonding to obtain homogeneous hybrid films. These PI hybrid films showed a tunable refractive index (1.60-1.81 for 4ATA-PI/TiO2 and 1.60-1.80 for 4ATA-PI/ZrO2), and the 4ATA-PI/ZrO2 hybrid films revealed a higher optical transparency and Abbe's number than those of the 4ATA-PI/TiO2 system due to a larger band gap of ZrO2. By introducing TiO2 and ZrO2 as the electron acceptor into the 4ATA-PI system, the hybrid materials have a lower LUMO energy level which could facilitate and stabilize the charge transfer complex. Therefore, memory devices derived from these PI hybrid films exhibited tunable memory properties from DRAM, SRAM, to WORM with a different TiO2 or ZrO2 content from 0 wt% to 50 wt% with a high ON/OFF ratio (108). In addition, the different energy levels of TiO2 and ZrO2 revealed specifically unique memory characteristics, implying the potential application of the prepared 4ATA-PI/TiO2 and 4ATA-PI/ZrO2 hybrid films in highly transparent memory devices.The novel bio-based polyimide (4ATA-PI) and the corresponding PI hybrids of TiO2 or ZrO2 with excellent optical properties and thermal stability have been prepared successfully. The highly transparent 4ATA-PI containing carboxylic acid groups in the backbone could provide reaction sites for organic-inorganic bonding to obtain homogeneous hybrid films. These PI hybrid films showed a tunable refractive index (1.60-1.81 for 4ATA-PI/TiO2 and 1.60-1.80 for 4ATA-PI/ZrO2), and the 4ATA-PI/ZrO2 hybrid films revealed a higher optical transparency and Abbe's number than those of the 4ATA-PI/TiO2 system due to a larger band gap of ZrO2. By introducing TiO2 and ZrO2 as the electron acceptor into the 4ATA-PI system

  5. 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.

  6. Slow charge recombination in dye-sensitised solar cells (DSSC) using Al2O3 coated nanoporous TiO2 films.

    Science.gov (United States)

    Palomares, Emilio; Clifford, John N; Haque, Saif A; Lutz, Thierry; Durrant, James R

    2002-07-21

    The conformal growth of an overlayer of Al2O3 on a nanocrystalline TiO2 film is shown to result in a 4-fold retardation of interfacial charge recombination, and a 30% improvement in photovoltaic device efficiency.

  7. Mystery of porous SnO 2 thin film formation by pulsed delivery

    Science.gov (United States)

    Chen, Z. W.; Lai, J. K. L.; Shek, C. H.

    2006-04-01

    We report a new kind of experimental realization of a porous SnO 2 thin film, which is based on a pulsed delivery process at room temperature. Microstructural analysis shows that the as-prepared thin film consists of a continuous network of interconnected crystalline SnO 2 nanoparticles (rutile structure). As a result, this porous SnO 2 thin film possesses a high surface area and continuous porosity, which is especially desirable for gas sensor design. The optical measurement shows that the porous SnO 2 thin film presents the surface characteristics that generate a red emission band that may be exploited in gas sensors or other optoelectronic devices.

  8. Structural and Luminescence Properties of Transparent Nanocrystalline ZrO2:Er3+ Films

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qin-Yuan; YANG Gang-Feng; JIANG Zhong-Hong; W. X. Que

    2006-01-01

    @@ The structural and luminescence properties of nanocrystalline ZrO2 :Er3+ films are reported. Transparent nanoZrO2 crystalline films doped with Er3+ have been prepared using a wet chemistry process. An intense roomtemperature emission at 1527nm with a full width at half-maximum of 46 nm has been observed, which is assigned to the 4 I13/2 → 4 I15/2 intra-4 fn electric transition of Er3+. Correlations between the luminescence properties and structures of the nanocrystalline ZrO2 :Er3+ films have been investigated. Infrared-to-visible upconversion occurs simultaneously upon excitation of a commercially available 980-nm laser diode and the involved mechanisms have also been explained. The results indicate that the nanocrystalline ZrO2:Er3+ films might be suggested as promising materials for achieving broadband Er3+-doped waveguide amplifiers and upconversion waveguide lasers.

  9. 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.

  10. 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.

  11. Nanocrystallization of LiCoO2 Cathodes for Thin Film Batteries Utilizing Pulse Thermal Processing

    Energy Technology Data Exchange (ETDEWEB)

    None

    2009-04-01

    This factsheet describes a study whose focus is on the nanocrystallization of the LiCoO2 cathode thin films on polyimide substrates and evaluate the microstructural evolution and resistance as a function of PTP processing conditions.

  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. Optical and electrical properties of electrochemically deposited polyaniline/CeO2 hybrid nanocomposite film

    Institute of Scientific and Technical Information of China (English)

    Anees A. Ansari; M. A. M. Khan; M. Naziruddin Khan; Salman A. Alrokayan; M. Alhoshan; M. S. Alsalhi

    2011-01-01

    This paper reports the optical and electrical properties of electrochemically deposited polyaniline (PANI)/cerium oxide (CeO2) hybrid nano-composite film onto indium-fin-oxide (ITO) glass substrate. UV-visible spectroscopy and I-V characteristic were performed to study the optical and electrical parameters of the electrochemically deposited film. The film exhibited a strong absorption below 400 nm (3.10 eV) with a well defined absorbance peak at around 285 nm (4.35 eV). The estimated band gap of the CeO2 sample was 3.44 eV, higher than bulk CeO2 powder (Eg = 3.19 eV) due to the quantum confinement effect. Optical and electrochemical characteristics indicated that the electrical properties of PANI/CeO2 hybrid nanocomposite film are dominated by PANI doping.

  14. Highly transparent and flexible bio-based polyimide/TiO2 and ZrO2 hybrid films with tunable refractive index, Abbe number, and memory properties.

    Science.gov (United States)

    Huang, Tzu-Tien; Tsai, Chia-Liang; Tateyama, Seiji; Kaneko, Tatsuo; Liou, Guey-Sheng

    2016-07-07

    The novel bio-based polyimide (4ATA-PI) and the corresponding PI hybrids of TiO2 or ZrO2 with excellent optical properties and thermal stability have been prepared successfully. The highly transparent 4ATA-PI containing carboxylic acid groups in the backbone could provide reaction sites for organic-inorganic bonding to obtain homogeneous hybrid films. These PI hybrid films showed a tunable refractive index (1.60-1.81 for 4ATA-PI/TiO2 and 1.60-1.80 for 4ATA-PI/ZrO2), and the 4ATA-PI/ZrO2 hybrid films revealed a higher optical transparency and Abbe's number than those of the 4ATA-PI/TiO2 system due to a larger band gap of ZrO2. By introducing TiO2 and ZrO2 as the electron acceptor into the 4ATA-PI system, the hybrid materials have a lower LUMO energy level which could facilitate and stabilize the charge transfer complex. Therefore, memory devices derived from these PI hybrid films exhibited tunable memory properties from DRAM, SRAM, to WORM with a different TiO2 or ZrO2 content from 0 wt% to 50 wt% with a high ON/OFF ratio (10(8)). In addition, the different energy levels of TiO2 and ZrO2 revealed specifically unique memory characteristics, implying the potential application of the prepared 4ATA-PI/TiO2 and 4ATA-PI/ZrO2 hybrid films in highly transparent memory devices.

  15. Characterization of sol-gel-prepared Ti02 thin film for O2 sensing

    Science.gov (United States)

    Atashbar, Massood Z.; Ghantasala, Muralihar K.; Wlodarski, Wojtek

    1997-11-01

    This paper presents the results of our investigation on deposition and characterization of sol-gel prepared TiO2 thin films for oxygen sensing applications. The properties of pure TiO2 thin films are compared with those doped with niobium oxide and 1%pt. These films are characterized using Rutherford backscattering spectroscopy (RBS), x-ray diffraction (XRD) and scanning electron microscopy (SEM) to study their chemical composition, structure and surface morphology respectively. Both kinds of the films are stoichiometric. Pure TiO2 as well as doped films were amorphous as deposited. Pure TiO2 films after annealing to 450 degrees Celsius and above showed the formation of anatase phase, while the doped films still predominantly amorphous, barely showing the onset of crystallinity. Pure films after annealing to 600 degrees Celsius appear to have become granular and porous. Doping with niobium oxide and Pt resulted in modification of film microstructure also. As a result of doping, the gas sensitivity of the films is increased from 8 to 24 and operating temperature decreased from 320 degrees Celsius to 190 degrees Celsius.

  16. 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.

  17. Structure and photochromic properties of molybdenumphosphoric acid/TiO2 composite films

    Institute of Scientific and Technical Information of China (English)

    QI He; LIU Yan; FENG Wei; ZHU YiMin

    2009-01-01

    TiO2 sol-gel composite films with dropping molybdenumphosphoric acid (PMoA) have been prepared by sol-gel method. The structure and constitute of composite thin films were studied with Fourier transforms infrared spectroscopy (FT-IR), atomic force microscopy (AFM), and X-ray diffraction (XRD) patterns, respectively. The photochromic behavior and mechanism of composite thin films were inves-tigated with ultraviolet-visible spectra (UV-vis) and electron spin resonance (ESR). FT-IR results showed that the Keggin geometry of PMoA was still preserved inside PMoA/TiO2 composite thin films, and a charge transfer bridge was built at the interface of PMoA and TiO2 through the Mo-O-Ti bond. Surface topography of the composite film showed obvious changes before/after adding PMoA, and the surface topography of composite films showed obvious changes before/after irradiating as well. Composite thin film had reversible photochromic properties. Irradiated with UV light, transparent films changed from colorless to blue and they can bleach completely with ambient air in the dark. ESR re-sults showed that TiO2 were excitated by UV light to produce electrons, which deoxidized PMoA to produce heteropolyblues. The photochromic process of PMoA/TiO2 system was carried through elec-tron transfer mechanism.

  18. Structure and photochromic properties of molybdenumphosphoric acid/TiO2 composite films

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    TiO2 sol-gel composite films with dropping molybdenumphosphoric acid(PMoA) have been prepared by sol-gel method.The structure and constitute of composite thin films were studied with Fourier transforms infrared spectroscopy(FT-IR),atomic force microscopy(AFM),and X-ray diffraction(XRD) patterns,respectively.The photochromic behavior and mechanism of composite thin films were inves-tigated with ultraviolet-visible spectra(UV-vis) and electron spin resonance(ESR).FT-IR results showed that the Keggin geometry of PMoA was still preserved inside PMoA/TiO2 composite thin films,and a charge transfer bridge was built at the interface of PMoA and TiO2 through the Mo-O-Ti bond.Surface topography of the composite film showed obvious changes before/after adding PMoA,and the surface topography of composite films showed obvious changes before/after irradiating as well.Composite thin film had reversible photochromic properties.Irradiated with UV light,transparent films changed from colorless to blue and they can bleach completely with ambient air in the dark.ESR re-sults showed that TiO2 were excitated by UV light to produce electrons,which deoxidized PMoA to produce heteropolyblues.The photochromic process of PMoA/TiO2 system was carried through elec-tron transfer mechanism.

  19. 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.

  20. Preparation and Properties of Dip-coated CeO2-TiO2 Thin Golden Glass Film

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The golden and ultraviolet-absorbed CeO2-TiO2 film was prepared on soda-lime glass substrate with the thickness of 2 mm via the sol-gel method. The transmission spectra in range of 200 nm-800 nm were measured, and the crystallization, the abrasion and acid resistance were also investigated. The appropriate sol contents and heat-treatment schedule were determined. The results indicate that the appropriate molar ratio of Ce/Ti was 3:5 to 5:6. The ultraviolet-absorbance ability increased with the increase of the Ce/Ti molar ratio, but when the Ce/Ti molar ratio was higher than 1.5, the homogeneity of the film was deteriorated. With the increase of heat-treatment temperature, the main wavelengths of the color of the coated glasses were equal, but the color's saturation decreased; the transmission peaks were the same, while the intensity of the peaks decreased. The roughness, abrasion and acid resistance of the film were also en hanced at the same time. The appropriate heattreatment temperature may be 340 ℃.

  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. Nanostructured Dense ZrO2 Thin Films from Nanoparticles Obtained by Emulsion Precipitation

    NARCIS (Netherlands)

    Woudenberg, Fiona C.M.; Sager, Wiebke F.C.; Elshof, ten Johan E.; Verweij, Henk

    2004-01-01

    Nonagglomerated spherical ZrO2 particles of 5–8 nm size were made by emulsion precipitation. Their crystallization and film-forming characteristics were investigated and compared with nanosized ZrO2 powders obtained by sol–gel precipitation. High-temperature X-ray diffraction indicated that the emul

  3. Adhesion of ultrathin ZrO2(111) films on Ni(111) from first principles

    DEFF Research Database (Denmark)

    Christensen, Asbjørn; Carter, Emily A.

    2001-01-01

    We have studied the ZrO2(111)/Ni(111) interface using the ultrasoft pseudopotential formalism within density functional theory. We find that ZrO2(111) adheres relatively strongly at the monolayer level but thicker ceramic films interact weakly with the Ni-substrate. We argue that the cohesion cha...

  4. Photochromic and self-cleaning properties of TiO2-AgCl/TiO2-xCu thin film.

    Science.gov (United States)

    Sangchay, Weerachai; Sikong, Lek; Kooptarnond, Kalayanee

    2013-02-01

    The TiO2-AgCl/TiO2-xCu thin films were prepared by sol-gel method and dip coated on glass slide. The prepared films were synthesized at the temperature of 400 degrees C for 2 h with a heating rate of 10 degrees C/min. The microstructure and properties of synthesized TiO2-AgCl/TiO2-xCu thin films were characterized by X-ray diffraction, scanning electron microscopy, atomic forced microscope and UV-vis diffuse reflectance spectroscopy. Finally, the hydrophilic property was evaluated by means of contact angle of water droplet on the films. The results show all samples have film thickness in range of 400-500 nm and their surfaces are dense and strong with a large surface area according to the image of atomic forced microscope. It can be noted that TiO2-AgCl/TiO2-5Cu thin films exhibit the highest photochromic (or the lowest capability of light transmittance) at 250-400 nm. The TiO2-AgCl/TiO2-xCu thin films can block UV C, UV B and UV A rays and exhibit self-cleaning effect (small contact angle, 3.9 degrees ) under UV irradiation.

  5. Preparations of TiO2 film coated on foam nickel substrate by sol-gel processes and its photocatalytic activity for degradation of acetaldehyde.

    Science.gov (United States)

    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 Ti02 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.

  6. Absorption enhancement in thin film a-Si solar cells with double-sided SiO2 particle layers

    Institute of Scientific and Technical Information of China (English)

    陈乐; 王庆康; 沈向前; 陈文; 黄堃; 刘代明

    2015-01-01

    Light absorption enhancement is very important for improving the power conversion efficiency of a thin film a-Si solar cell. In this paper, a thin-film a-Si solar cell model with double-sided SiO2 particle layers is designed, and then the underlying mechanism of absorption enhancement is investigated by finite difference time domain (FDTD) simulation;finally the feasible experimental scheme for preparing the SiO2 particle layer is discussed. It is found that the top and bottom SiO2 particle layers play an important role in anti-reflection and light trapping, respectively. The light absorption of the cell with double-sided SiO2 layers greatly increases in a wavelength range of 300 nm–800 nm, and the ultimate efficiency increases more than 22%compared with that of the flat device. The cell model with double-sided SiO2 particle layers reported here can be used in varieties of thin film solar cells to further improve their performances.

  7. 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.

  8. Enhancement of Ammonia Sensitivity in Swift Heavy Ion Irradiated Nanocrystalline SnO2 Thin Films

    Directory of Open Access Journals (Sweden)

    Sanju Rani

    2008-01-01

    Full Text Available Swift heavy ion irradiation is an effective technique to induce changes in the microstructure and electronic energy levels of materials leading to significant modification of properties. Here we report enhancement of ammonia (NH3 sensitivity of SnO2 thin films subjected to high-energy Ni+ ion irradiation. Sol-gel-derived SnO2 thin films (100 nm thickness were exposed to 75 MeV Ni+ ion irradiation, and the gas response characteristics of irradiated films were studied as a function of ion fluence. The irradiated films showed p-type conductivity with a much higher response to NH3 compared to other gases such as ethanol. The observed enhancement of NH3 sensitivity is discussed in context of ion beam generated electronic states in the SnO2 thin films.

  9. Superhydrophobicity and regeneration of PVDF/SiO2 composite films

    Science.gov (United States)

    Liu, Tao; Li, Xianfeng; Wang, Daohui; Huang, Qinglin; Liu, Zhen; Li, Nana; Xiao, Changfa

    2017-02-01

    Superhydrophobicity of polymers is easily destroyed by careless touching due to the softness of microstructures. In this study, based on a well-constructed polyvinylidene fluoride (PVDF) surface, a novel superhydrophobic PVDF/SiO2 composite film was fabricated by adding hydrophobic SiO2 nanoparticle and solvent into a coagulation bath. The water contact angle of the composite film reached 162.3° and the sliding angle was as low as 1.5°. More importantly, the composite film could be regenerated only through immersing the composite film in the designed regeneration agent. The composition of the designed regeneration agent ensured that SiO2 nanoparticles were firmly adhered on the film surface even under the ultrasonic cleaning. Hence, the superhydrophobicity and self-cleaing property could be regenerated and maintained effectively, and moreover, these propeties could resist a proper pressure. In addition, after many rubbing-regenerating cycles, the regeneration method was still valid.

  10. 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.

  11. 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.

  12. 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.

  13. Optoelectronic properties of SnO2 thin films sprayed at different deposition times

    Science.gov (United States)

    Allag, Abdelkrim; Saâd, Rahmane; Ouahab, Abdelouahab; Attouche, Hafida; Kouidri, Nabila

    2016-04-01

    This article presents the elaboration of tin oxide (SnO2) thin films on glass substrates by using a home-made spray pyrolysis system. Effects of film thickness on the structural, optical, and electrical film properties are investigated. The films are characterized by several techniques such as x-ray diffraction (XRD), atomic force microscopy (AFM), ultraviolet-visible (UV-Vis) transmission, and four-probe point measurements, and the results suggest that the prepared films are uniform and well adherent to the substrates. X-ray diffraction (XRD) patterns show that SnO2 film is of polycrystal with cassiterite tetragonal crystal structure and a preferential orientation along the (110) plane. The calculated grain sizes are in a range from 32.93 nm to 56.88 nm. Optical transmittance spectra of the films show that their high transparency average transmittances are greater than 65% in the visible region. The optical gaps of SnO2 thin films are found to be in a range of 3.64 eV-3.94 eV. Figures of merit for SnO2 thin films reveal that their maximum value is about 1.15 × 10-4 Ω-1 at λ = 550 nm. Moreover, the measured electrical resistivity at room temperature is on the order of 10-2 Ω·cm.

  14. 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.

  15. Comparison of TiO2 and ZrO2 Films Deposited by Electron-Beam Evaporation and by Sol-Gel Process

    Institute of Scientific and Technical Information of China (English)

    YAO Jian-Ke; LI Hai-Yuan; FAN Zheng-Xiu; TANG Yong-Xing; JIN Yun-Xia; ZHAO Yuan-An; HE Hong-Bo; SHAO Jian-Da

    2007-01-01

    TiO2 and ZrO2 films are deposited by electron-beam (EB) evaporation and by sol-gel process. The film properties are characterized by visible and Fourier-transform infrared spectrometry, x-ray diffraction analysis, surface roughness measure, absorption and laser-induced damage threshold (LIDT) test. It is found that the sol-gel films have lower refractive index, packing density and roughness than EB deposited films due to their amorphous structure and high OH group concentration in the film. The high LIDT of sol-gel films is mainly due to their amorphous and porous structure, and low absorption. LIDT of EB deposited film is considerably affected by defects in the film, and LIDT of sol-gel deposited film is mainly effected by residual organic impurities and solvent trapped in the film.

  16. Análise por difração de raios x de filmes de óxidos cerâmicos compostos por IrO2/TiO2/CeO2

    Directory of Open Access Journals (Sweden)

    Alves Valéria Almeida

    2000-01-01

    Full Text Available Independent of the sample form (powder or film, XRD analysis of Ir0,3Ti(0,7-xCe xO2, (nominal mixtures, for x=0, shows the formation of a solid solution phase between IrO2 and TiO2, as well as the rutile phases of IrO2 and TiO2. The presence of the anatase phase of TiO2 is also confirmed. The introduction of 30 mol% CeO2 in the mixture reveals the presence of the CeO2 and Ce2O3 phases, besides the already mentioned ones, in the powder. In the film form, however, an amorphous phase is identified. When all of the TiO2 is substituded by CeO2, for both sample forms, the only phases found are IrO2, CeO2 and Ce2O3. This result suggests cerium oxides are not capable of forming solid solutions with either IrO2 or (Ir,TiO2 acting solely as a dispersant matrix for these phases. These results are consistent with the much higher electrochemically active surface area when CeO2 is introduced in the binary Ti/Ir0,3Ti0,7O2 mixture. It was possible to establish a relationship between the electrochemical stability of the supported films and their crystalline structure. The unexpected presence of TiO2 and Ti2O3 in the Ti/Ir0,3Ce0,7O2 (film sample is attributed to oxidation of the Ti support during the calcination step.

  17. Preparation and characterization of nanostructured Pt/TiO2 thin films treated using electron beam.

    Science.gov (United States)

    Shin, Joong-Hyeok; Woo, Hee-Gweon; Kim, Bo-Hye; Lee, Byung Cheol; Jun, Jin

    2010-05-01

    Pt nanoparticle-doped titanium dioxide (Pt/TiO2) thin films were prepared on a silicon wafer substrate by sol-gel spin coating process. The prepared thin films were treated with electron beam (EB at 1.1 MeV, 100, 200, 300 kGy) at air atmosphere. The effect of EB-irradiation on the composition of the treated thin films, optical properties and morphology of thin films were investigated by various analytical techniques such as X-ray photoelectron spectroscopy (XPS), spectroscopic ellipsometry (SE), X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The crystal structure of the TiO2 layer was found to be an anatase phase and the size of TiO2 particles was determined to be about 13 nm. Pt nanoparticles with diameter of 5 nm were observed on surface of the films. A new layer (presumed to be Pt-Ti complex and/or PtO2 compound) was created in the Pt/TiO2 thin film treated with EB (300 kGy). The transmittance of thin film decreased with EB treatment whereas the refractive index increased.

  18. 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.

  19. Improved osteoblast response to UV-irradiated PMMA/TiO2 nanocomposites with controllable wettability.

    Science.gov (United States)

    Shayan, Mahdis; Jung, Youngsoo; Huang, Po-Shun; Moradi, Marzyeh; Plakseychuk, Anton Y; Lee, Jung-Kun; Shankar, Ravi; Chun, Youngjae

    2014-12-01

    Osteoblast response was evaluated with polymethylmethacrylate (PMMA)/titanium dioxide (TiO2) nanocomposite thin films that exhibit the controllable wettability with ultraviolet (UV) treatment. In this study, three samples of PMMA/TiO2 were fabricated with three different compositional volume ratios (i.e., 25/75, 50/50, and 75/25) followed by UV treatment for 0, 4, and 8 h. All samples showed the increased hydrophilicity after UV irradiation. The films fabricated with the greater amount of TiO2 and treated with the longer UV irradiation time increased the hydrophilicity more. The partial elimination of PMMA on the surface after UV irradiation created a durable hydrophilic surface by (1) exposing higher amount of TiO2 on the surface, (2) increasing the hydroxyl groups on the TiO2 surface, and (3) producing a mesoporous structure that helps to hold the water molecules on the surface longer. The partial elimination of PMMA on the surface was confirmed by Fourier transform infrared spectroscopy. Surface profiler and atomic force microscopy demonstrated the increased surface roughness after UV irradiation. Both scanning electron microscopy and energy-dispersive X-ray spectroscopy demonstrated that particles containing calcium and phosphate elements appeared on the 8 h UV-treated surface of PMMA/TiO2 25/75 samples after 4 days soaking in Dulbecco's Modified Eagle Medium. UV treatment showed the osteoblast adhesion improved on all the surfaces. While all UV-treated hydrophilic samples demonstrated the improvement of osteoblast cell adhesion, the PMMA/TiO2 25/75 sample after 8 h UV irradiation (n = 5, P value = 0.000) represented the best cellular response as compared to other samples. UV-treated PMMA/TiO2 nanocomposite thin films with controllable surface properties represent a high potential for the biomaterials used in both orthopedic and dental applications.

  20. 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.

  1. Optical, electrical and dielectric properties of TiO2-SiO2 films prepared by a cost effective sol-gel process.

    Science.gov (United States)

    Vishwas, M; Rao, K Narasimha; Gowda, K V Arjuna; Chakradhar, R P S

    2011-12-01

    Titanium dioxide (TiO(2)) and silicon dioxide (SiO(2)) thin films and their mixed films were synthesized by the sol-gel spin coating method using titanium tetra isopropoxide (TTIP) and tetra ethyl ortho silicate (TEOS) as the precursor materials for TiO(2) and SiO(2) respectively. The pure and composite films of TiO(2) and SiO(2) were deposited on glass and silicon substrates. The optical properties were studied for different compositions of TiO(2) and SiO(2) sols and the refractive index and optical band gap energies were estimated. MOS capacitors were fabricated using TiO(2) films on p-silicon (100) substrates. The current-voltage (I-V) and capacitance-voltage (C-V) characteristics were studied and the electrical resistivity and dielectric constant were estimated for the films annealed at 200°C for their possible use in optoelectronic applications.

  2. Characterization of TiO2/Ta2O5 Films Synthesized by Ion Beam on NiTi Alloy for Biomedical Applications

    Institute of Scientific and Technical Information of China (English)

    Jingxiao LIU; Jihua CHEN; Dazhi YANG; Weiqiang WANG; Yinong WANG; Yingji CAI

    2001-01-01

    The biocompatibility of implants is determined by their corrosion resistance and surface characteristics. in this study, the surface composition, morphology and microstructure of TiO2/Ta2O5 films synthesized by ion beam enhanced deposition on NiTi alloy were studied. The scratch test results indicate that the interface adhesive strength of TiO2/Ta2O5 film increases with the increasing Ta content. The electrochemical corrosion measurement shows that the TiO2-36%Ta2O5 film is optimal for improving corrosion resistance of NiTi alloy.

  3. 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.

  4. 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.

  5. 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.

  6. Fabrication of LiCoO 2 cathode powder for thin film battery by aerosol flame deposition

    Science.gov (United States)

    Lee, Taewon; Cho, Kihyun; Oh, Jangwon; Shin, Dongwook

    Crystalline LiCoO 2 nano-particles for thin film battery were synthesized and deposited by aerosol flame deposition (AFD). The aqueous precursor solution of the lithium nitrate and cobalt acetate was atomized with an ultrasonic vibrator and subsequently carried into the central tube of the torch by flowing dry Ar gas. LiCoO 2 were formed by oxy-hydrogen flame and deposited on a substrate placed in a heating stage. The deposited soot film composed of nano-sized particles was subsequently consolidated into a dense film by high temperature heat treatment at 500-800 °C for 5 h and characterized by SEM, XRD, and Raman spectroscopy. The crystalline carbonates and oxide were first formed by the deposition and the subsequent heat treatment converted those to LiCoO 2. The FWHMs of the XRD peaks were reduced and their intensity increased as the heat treatment temperature increased, which is due to improved crystallinity. When judged from the low enough cation mixing and well-developed layered structure, it is believed that the LiCoO 2 film satisfied the quality standard for the real application. SEM measurements showed that LiCoO 2 were nano-crystalline structure with the average particle size <70 nm and the particle size increased with the increase of heat treatment temperature. The thickness of thin film LiCoO 2 before the consolidation process was about 15 μm and reduced to about 4 μm after sintering.

  7. Synthesis and Properties of Nd-doped TiO2 thin films by sol-gel dip-coating method

    Directory of Open Access Journals (Sweden)

    Wang Jun

    2016-01-01

    Full Text Available TiO2 thin films doped with neodymium(Nd in the range from 0 at.% to 10at. % were prepared on glass substrates by sol-gel dip-coating method. Water contact angle on the Nd-doped TiO2 films were measured by contact angle analyzer. The water contact angle measurement result showed that the hydrophily of the films improved when the Nd3+ concentration increased to 5 at.%. The photocatalytic activity of the undoped and Nd-doped TiO2 thin films were investigated by the degradation of methylene blue under high-voltage mercury lamp. The results showed that 5 at.% Nd-doped TiO2 thin film exhibited the highest photocatalytic efficiency.

  8. Preparation of perpendicular oriented TiO2 films via hydrothermal method: phase selection and growth control

    Science.gov (United States)

    Gao, Yun; Guo, Meilan; Xia, Xiaohong; Shao, Guosheng

    2013-03-01

    Either rutile or anatase vertical orientated TiO2 array films were synthesized successfully on FTO (F: SnO2) substrate via hydrothermal method through controlling the concentration of Cl- and SO42- . The density of nanorods can be adjusted by varying the volume ratio of ethanol/water, and the degree of orientation and crystallinity of TiO2 nanofilms were enhanced with increasing dosage of ethanol. Meanwhile, completely dense anatase films with [004] oriented growth appear within a very narrow concentration window when adding sulfuric acid into precursor. Besides, other alcohols such as methanol, n-propanol and n-butyl were also used as solvent to examine the role of alcohol type during hydrothermal process for both two phase films. The growth rate and degree of perpendicular orientation declined as the alkyl length of solvents increases. Hydrogen sensing characteristics of dense films of both rutile and anatase phases showed that there was a remarkable improvement of sensitivity response over reported data. It was found that rutile films have higher sensitivity while anatase films have faster response. This work is supported by Ministry of Education of China (211108) and Science and Technology of Wuhan (2010CDA024, 201110821251).

  9. Surface Modification of Aerosol-Assisted CVD Produced TiO2 Thin Film for Dye Sensitised Solar Cell

    Directory of Open Access Journals (Sweden)

    SuPei Lim

    2014-01-01

    Full Text Available We report a simple and convenient method for the preparation of Ag/TiO2 thin films supported on indium tin oxide, which was achieved by sonochemical deposition of Ag+ on aerosol-assisted chemical vapour deposited TiO2 thin films. Posttreatment was performed on the film by immersion in HCl. The as-prepared composite film was characterised by X-ray diffraction, ultraviolet-visible absorption spectroscopy, Raman spectroscopy, and field emission scanning electron microscopy. The photoelectrochemical measurements and J-V characterisation showed approximately fivefold increase in photocurrent density generation and approximately sevenfold enhancement in dye sensitiser solar cell (DSSC conversion efficiency, which was achieved after modification of the TiO2 film with HCl posttreatment and Ag particle deposition. The improved photocurrent density of 933.30 μA/cm2, as well as DSSC power conversion efficiency of 3.63% with high stability, is an indication that the as-synthesised thin film is a potential candidate for solar energy conversion applications.

  10. 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.

  11. 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.

  12. Structural degradation of thin HfO2 film on Ge during the postdeposition annealing

    Science.gov (United States)

    Miyata, Noriyuki; Yasuda, Tetsuji; Abe, Yasuhiro

    2010-05-01

    Securing the thermal robustness of thin hafnium oxide (HfO2) film on the semiconductor surface is an important technical issue in the fabrication of the metal-oxide-semiconductor field-effect transistor devices, as the HfO2-based high-k gate stacks usually undergo high-temperature processes. In this study, the structural development of thin HfO2 film on a Ge surface during postdeposition annealing in an ultrahigh vacuum was examined to explore the origin for the initial degradation of thin HfO2 film. Void nucleation and subsequent two-dimensional void growth take place at 780-840 °C, while the chemical composition of the remaining Hf oxide is virtually stable. Both the void nucleation and growth processes show similar larger activation energy of about 10 eV. Based on the observed manner of void growth and the estimated activation energies, the authors propose that mass transport on the HfO2 surface is responsible for void nucleation in the HfO2 films on Ge. The authors also compare the present results with the previous studies on HfO2/Si structures, and suggest that similar surface process leads to the local Hf silicidation.

  13. 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.

  14. Photolysis of pure solid O3 and O2 films at 193 nm

    CERN Document Server

    Raut, U; Famá, M; Baragiola, R A

    2010-01-01

    We studied quantitatively the photochemistry of solid O3 and O2 films at 193 nm and 22 K with infrared spectroscopy and microgravimetry. Photolysis of pure ozone destroyed O3, but a small amount of ozone remained in the film at high fluence. Photolysis of pure O2 produced O3 in an amount that increased with photon fluence to a stationary level. For both O2 and O3 films, the O3:O2 ratio at saturation is 0.03, nearly 10-30 times larger than those obtained in gas phase photolysis. This enhancement is attributed to the increased photodissociation of O2 due to photoabsorption by O2 dimers, a process significant at solid state densities. We obtain initial quantum yield for ozone synthesis from solid oxygen, {\\Phi} (O3) = 0.18 and for destruction of ozone and oxygen in their parent solids, {\\Phi} (- O3) = 1.7 and {\\Phi} (-O2) = 0.28. Combined with known photoabsorption cross sections, we estimate probabilities for germinate recombination of 0.15 for O3 fragments and 0.90 for oxygen atoms from O2 dissociation. Using ...

  15. Enhanced Photoelectrocatalytic Reduction of Oxygen Using Au@TiO2 Plasmonic Film.

    Science.gov (United States)

    Guo, Limin; Liang, Kun; Marcus, Kyle; Li, Zhao; Zhou, Le; Mani, Prabhu Doss; Chen, Hao; Shen, Chen; Dong, Yajie; Zhai, Lei; Coffey, Kevin R; Orlovskaya, Nina; Sohn, Yong-Ho; Yang, Yang

    2016-12-28

    Novel Au@TiO2 plasmonic films were fabricated by individually placing Au nanoparticles into TiO2 nanocavity arrays through a sputtering and dewetting process. These discrete Au nanoparticles in TiO2 nanocavities showed strong visible-light absorption due to the plasmonic resonance. Photoelectrochemical studies demonstrated that the developed Au@TiO2 plasmonic films exhibited significantly enhanced catalytic activities toward oxygen reduction reactions with an onset potential of 0.92 V (vs reversible hydrogen electrode), electron transfer number of 3.94, and limiting current density of 5.2 mA cm(-2). A superior ORR activity of 310 mA mg(-1) is achieved using low Au loading mass. The isolated Au nanoparticle size remarkably affected the catalytic activities of Au@TiO2, and TiO2 coated with 5 nm Au (Au5@TiO2) exhibited the best catalytic function to reduce oxygen. The plasmon-enhanced reductive activity is attributed to the surface plasmonic resonance of isolated Au nanoparticles in TiO2 nanocavities and suppressed electron recombination. This work provides comprehensive understanding of a novel plasmonic system using isolated noble metals into nanostructured semiconductor films as a potential alternative catalyst for oxygen reduction reaction.

  16. Growth of HT-LiCoO2 thin films on Pt-metalized silicon substrates

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yao; CHUNG Chiyuen; ZHU Min

    2008-01-01

    Layered LiCoO2 (HT-LiCoO2) films were grown on Pt-metalized silicon (PMS) substrates and polished bulk nickel (PBN) substrates by pulsed laser deposition. The effects of substrate temperature, oxygen pressure, and substrate surface roughness on the microstructure of LiCoO2 films were investigated. It has been found that a higher substrate temperature and a higher oxygen pressure favor the formation of better crystallized and less lithium-deficient HT-LiCoO2 films. The HT-LiCoO2 film deposited on PBN substrates consists of large randomly orientated equiaxial grains, whereas on PMS substrate, it is made up of loosely packed highly [001] preferential orientated triangular shaped grains with the average grain size less than 100nm. Electrochemical measurements show that the highly [001] preferentially orientated nanostructured HT-LiCoO2 thin film grown on PMS substrate has good structural stability upon lithium insertion/extraction and can deliver an initial discharge capacity of approximately 45 μA·h·cm-2μm-1 with a cycling efficiency of above 99% at the charge/discharge rate of 0.5C.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Size effects on thermoelectric behavior of ultrathin NaxCoO2 films

    NARCIS (Netherlands)

    Brinks, Peter; Rijnders, Guus; Huijben, Mark

    2014-01-01

    Size effects in thermoelectric Na x CoO2 thin films are studied, focusing on the electrical resisitivity and Seebeck coefficient. For very thin films below 10 nm, we have observed an increase in resistivity, which is in agreement with theoretical models. In contrast to a predicted simultaneous suppr

  2. Nanoscale morphological and electrical homogeneity of HfO2 and ZrO2 thin films studied by conducting atomic-force microscopy

    Science.gov (United States)

    Kremmer, S.; Wurmbauer, H.; Teichert, C.; Tallarida, G.; Spiga, S.; Wiemer, C.; Fanciulli, M.

    2005-04-01

    The morphological and electrical evolution of HfO2 and ZrO2 thin films is investigated on the nanoscale using conducting atomic-force microscopy in ultrahigh vacuum. Films of different thicknesses have been grown by atomic layer deposition. With increasing film thickness the film structure changes from amorphous to polycrystalline. By conducting atomic-force microscopy using local current-voltage curve statistics and two-dimensional current imaging it is found that the formation of crystallites has different effects on the electrical properties of the two dielectrics. In the case of HfO2, the crystalline fraction causes weak spots in the oxide, whereas for the ZrO2 films the crystallites exhibit lower leakage currents compared to the amorphous matrix and leakage is mainly determined by thickness fluctuations.

  3. 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.

  4. Investigations of the structural, morphological and electrical properties of multilayer ZnO/TiO2 thin films, deposited by sol-gel technique

    Science.gov (United States)

    Khan, M. I.; Bhatti, K. A.; Qindeel, Rabia; Bousiakou, Leda G.; Alonizan, Norah; Fazal-e-Aleem

    Investigations of the structural, morphological and electrical properties of multilayer ZnO/TiO2 thin films deposited by sol-gel technique on glass substrate. Sol-gel is a technique in which compound is dissolved in a liquid in order to bring it back as a solid in a controlled manner. TiO2 solution was obtained by dissolving 0.4 g of TiO2 nano powder in 5 ml ethanol and 5 ml diethylene glycol. ZnO solution was obtained by dissolving 0.88 g zinc acetate in 20 ml of 2-methoxyethanol. X-ray diffraction (XRD) (PW 3050/60 PANalytical X'Pert PRO diffractometer) results showed that the crystallinity is improved when the number of ZnO/TiO2 layers increased. Also it shows the three phases (rutile, anatase and brookite) of TiO2. Surface morphology measured by scanning electron microscopy (SEM) (Quanta 250 fei) revealed that Crakes are present on the surface of ZnO/TiO2 thin films which are decreased when the number of ZnO/TiO2 layers increased. Four point probe (KIETHLEY instrument) technique used to investigate the electrical properties of ZnO/TiO2 showed the average resistivity decreased by increasing the number of ZnO/TiO2 layers. These results indicated that the multilayer thin films improved the quality of film crystallinity and electrical properties as compared to single layer.

  5. [Study on preparation of lanthanum-doped TiO2 nanometer thin film materials and its photocatalytic activity].

    Science.gov (United States)

    Zheng, Huai-li; Tang, Ming-fang; Gong, Ying-kun; Deng, Xiao-jun; Wu, Bang-hua

    2003-04-01

    In this paper, lanthanum-doped TiO2 nanometer film materials coated on glass were prepared in Ti(OBu)4 precursor solutions by sol-gel processing. Transmittance and photocatalytic activity were respectively investigated and tested for these nanometer thin films prepared with different amount of lanthanum (La), different amount of polyethylene glycol (PEG), and different coating layer times. Some reactive mechanisms were also discussed. For one layer La-addition had little effect on the film transmissivity; but the photocatalytic activity was significantly improved due to La-addition. With increasing PEG, the transmittance of the film decreased for one layer film; but its photocatalytic activity did not rise. Increasing layer number did not affect the transmissivity of multilayer film. After coating two times, increasing layer number did not significantly improve the photocatalytic activity. The highest photocatalytic activity and best transmissivity were obtained for two layer TiO2 film when the dosage of lanthanum was 0.5 g and the dosage of polyethylene was 0.2 g in the precursor solutions. These materials will probably be used in the protection of environment, waste water treatment, and air purification.

  6. Sequential Processes to Produce N-TiO2 Films Through Rf Plasmas

    Directory of Open Access Journals (Sweden)

    Valencia-Alvarado R

    2016-01-01

    Full Text Available Using as target a CpTi disk in an atmosphere of argon/oxygen and by rf plasma. First titanium dioxide (TiO2 films were obtained on silicon substrates, and subsequently, these films were doped with nitrogen (N-TiO2. In both processes, along four hours at 390°C of temperature. X-Ray diffraction and Raman spectroscopy confirmed the presence of the nanostructured anatase phase. X-ray photoelectron spectroscopy analyzes indicate that the nitrogen atoms were incorporated into the TiO2 film with ~33.9 at%. The films reach a thickness of 1.25 μm and 40 nm the average uniformity determined by using an atomic force microscope. Finally, UV-Vis diffuse reflectance spectroscopy outcome evaluated ones an energy band gap reduction from 3.17 eV to 2.95 eV corresponding to TiO2 films and N-TiO2 films respectively.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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 ...

  13. Improved Workability of the Nanocomposited AgSnO2 Contact Material and Its Microstructure Control During the Arcing Process

    Science.gov (United States)

    Wang, Yaping; Li, Haiyan

    2017-02-01

    There are two major weaknesses for the AgSnO2 contacts used in the low voltage switch devices. One is poor workability, which causes the AgSnO2 materials to hardly deform into the required shape. Another is the increased contact resistance after arcing, which, in turn, causes an unfavorable temperature rise in the switches. In this article, the nanocomposited AgSnO2 materials were developed to overcome the weaknesses. The nanosized SnO2 powders with or without CuO additive were prepared by the chemical precipitation method. The SnO2 powders and Ag powders were high energy milled together to obtain AgSnO2 composite powders, which were then sintered, hot pressed and extruded. It was found that the SnO2 particles mainly distribute in the interior of Ag grains with Ag film on the grain boundary. The hardness of AgSnO2 composites and the wetting angle of Ag melt on SnO2 particles decreased with the addition of a small amount of CuO. By the combining effect of Ag film on grain boundary and the addition of CuO, the elongation and workability of the AgSnO2 materials improved. The experiments of rapid solidification revealed that more SnO2 particles with CuO addition were engulfed in the Ag matrix than those without CuO, which inhibited the redistribution of SnO2 particles on the contact surface during the arcing process. The industrial type test in the 45A contactor suggested that the nanocomposited AgSnO2 materials are suitable to be used as contacts in low voltage switches.

  14. 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.

  15. 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.

  16. Colossal photo-conductive gain in low temperature processed TiO2 films and their application in quantum dot solar cells

    Science.gov (United States)

    Mandal, Debranjan; Goswami, Prasenjit N.; Rath, Arup K.

    2017-03-01

    Colloidal quantum dot (QD) solar cells have seen remarkable progress in recent past to reach the certified efficiency of 10.6%. Anatase titanium oxide (TiO2) is a widely studied n-type widow layer for the collection of photogenerated electrons in QD solar cells. Requirement of high temperature (˜500 °C) processing steps proved to be disadvantageous for its applications in flexible solar cells and roll to roll processing, and it also has adverse commercial implications. Here, we report that solar light exposure to low temperature processed (80 °C-150 °C) TiO2 and niobium doped TiO2 films leads to unprecedented enhancement in their electron densities and electron mobilities, which enables them to be used as efficient n-type layers in quantum dot solar cells. Such photoinduced high conducting states in these films show gradual decay over hours after the light bias is taken off and can be retrieved under solar illumination. On the contrary, TiO2 films processed at 500 °C show marginal photo induced enhancements in their characteristics. In bilayer configuration with PbS QDs, photovoltaic devices based on low temperature processed TiO2 films show improved performance over high temperature processed TiO2 films. The stability of photovoltaic devices also improved in low temperature processed TiO2 films under ambient working conditions.

  17. 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.

  18. 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.

  19. Preparation and Optimization of Fluorescent Thin Films of Rosamine-SiO2/TiO2 Composites for NO2 Sensing

    Science.gov (United States)

    Guillén, María G.; Gámez, Francisco; Suárez, Belén; Queirós, Carla; Silva, Ana M. G.; Barranco, Ángel; Sánchez-Valencia, Juan Ramón; Pedrosa, José María; Lopes-Costa, Tânia

    2017-01-01

    The incorporation of a prototypical rosamine fluorescent dye from organic solutions into transparent and microstructured columnar TiO2 and SiO2 (MO2) thin films, prepared by evaporation at glancing angles (GAPVD), was evaluated. The aggregation of the adsorbed molecules, the infiltration efficiency and the adsorption kinetics were studied by means of UV-Vis absorption and fluorescence spectroscopies. Specifically, the infiltration equilibrium as well as the kinetic of adsorption of the emitting dye has been described by a Langmuir type adsorption isotherm and a pseudosecond order kinetic model, respectively. The anchoring mechanism of the rosamine to the MO2 matrix has been revealed by specular reflectance Fourier transform infrared spectroscopy and infiltration from aqueous solutions at different pH values. Finally, the sensing performance towards NO2 gas of optimized films has been assessed by following the changes of its fluorescence intensity revealing that the so-selected device exhibited improved sensing response compared to similar hybrid films reported in the literature. PMID:28772484

  20. Preparation and Optimization of Fluorescent Thin Films of Rosamine-SiO2/TiO2 Composites for NO2 Sensing

    Directory of Open Access Journals (Sweden)

    María G. Guillén

    2017-01-01

    Full Text Available The incorporation of a prototypical rosamine fluorescent dye from organic solutions into transparent and microstructured columnar TiO2 and SiO2 (MO2 thin films, prepared by evaporation at glancing angles (GAPVD, was evaluated. The aggregation of the adsorbed molecules, the infiltration efficiency and the adsorption kinetics were studied by means of UV-Vis absorption and fluorescence spectroscopies. Specifically, the infiltration equilibrium as well as the kinetic of adsorption of the emitting dye has been described by a Langmuir type adsorption isotherm and a pseudosecond order kinetic model, respectively. The anchoring mechanism of the rosamine to the MO2 matrix has been revealed by specular reflectance Fourier transform infrared spectroscopy and infiltration from aqueous solutions at different pH values. Finally, the sensing performance towards NO2 gas of optimized films has been assessed by following the changes of its fluorescence intensity revealing that the so-selected device exhibited improved sensing response compared to similar hybrid films reported in the literature.

  1. Using Ⅰ-Ⅴ characteristics to investigate selected contacts for SnO2:F thin films

    Institute of Scientific and Technical Information of China (English)

    Shadia.J.Ikhmayies; Riyad N Ahmad-Bitar

    2012-01-01

    Fluorine doped tin oxide (SnO2:F) thin films were prepared on glass substrates by the spray pyrolysis (SP) technique at different substrate temperatures between 380-480 ℃.The microstructure of the films was explored using scanning electron microscope observations.An investigation of selected contacts for the films was performed through the analysis of the Ⅰ-Ⅴ measurements which were taken in the dark at room temperature.Indium,aluminum and silver were selected as contacts where two strips of each metal were vacuum-evaporated on the surface of the film.The resistivity of the films was estimated from the linear Ⅰ-Ⅴ plots.It was found that the smallest resistivity was obtained using silver contacts,while the largest resistivity was obtained by using indium contacts.This is because silver diffuses in the film and participates in doping,while aluminum and indium cause compensation effects when they diffuse in the film.The best linear fit parameters are those of films with aluminum contacts,and the worst ones are those of films with indium contacts.Annealing was found to improve the electrical properties of the films,especially those deposited at a low substrate temperature.This is because it is expected to encourage crystal growth and to reduce the contact potential which leads to the formation of an alloy.Annealed films are more stable than un-annealed ones.

  2. The demonstration of significant ferroelectricity in epitaxial Y-doped HfO2 film

    OpenAIRE

    Takao Shimizu; Kiliha Katayama; Takanori Kiguchi; Akihiro Akama; Konno, Toyohiko J.; Osami Sakata; Hiroshi Funakubo

    2016-01-01

    Ferroelectricity and Curie temperature are demonstrated for epitaxial Y-doped HfO2 film grown on (110) yttrium oxide-stabilized zirconium oxide (YSZ) single crystal using Sn-doped In2O3 (ITO) as bottom electrodes. The XRD measurements for epitaxial film enabled us to investigate its detailed crystal structure including orientations of the film. The ferroelectricity was confirmed by electric displacement filed – electric filed hysteresis measurement, which revealed saturated polarization of 16...

  3. Solid-state dewetting of ultra-thin Au films on SiO2 and HfO2

    Science.gov (United States)

    Seguini, G.; Llamoja Curi, J.; Spiga, S.; Tallarida, G.; Wiemer, C.; Perego, M.

    2014-12-01

    Ultra-thin Au films with thickness (h) ranging from 0.5 to 6.0 nm were deposited at room temperature (RT) by means of e-beam evaporation on SiO2 and HfO2. Due to the natural solid-state dewetting (SSD) of the as-deposited films, Au nanoparticles (NPs) were formed on the substrates. By properly adjusting the h value, the size and the density of the Au NPs can be finely tuned. For h = 0.5 nm, spherical-like Au NPs with diameter below 5 nm and density in the order of 1012 Au NPs cm-2 were obtained without any additional thermal treatment independently from the substrate. The dependence of the Au NPs characteristics on the substrate starts to be effective for h ≥ 1.0 nm where the Au NPs diameter is in the 5-10 nm range and the density is around 1011 Au NPs cm-2. The effect of a subsequent high temperature (400-800 °C) annealing in N2 atmosphere on the Au NPs was investigated as well. For h ≤ 1.0 nm, the Au NPs characteristics evidenced an excellent thermal stability. Whereas the thermal treatment affects the cristallinity of the Au NPs. For the thicker films (2.0 ≤ h ≤ 6.0 nm), the thermal treatment becomes effective to induce the SSD. The proposed methodology can be exploited for the synthesis of Au NPs with diameter below 10 nm on different substrates at RT.

  4. I-TiO2/PVC film with highly photocatalytic antibacterial activity under visible light.

    Science.gov (United States)

    Deng, Weihua; Ning, Shangbo; Lin, Qianying; Zhang, Hualei; Zhou, Tanghua; Lin, Huaxiang; Long, Jinlin; Lin, Qun; Wang, Xuxu

    2016-08-01

    Iodine-modified TiO2(I-TiO2) film were coated on medical-grade PVC material by impregnation-deposition method and subsequently characterized by XRD, SEM, TEM, AFM, DRS and XPS. The photocatalytic anti-bacterial activity of I-TiO2/PVC was investigated both by in vitro anti-bacterial experiments and by clinical study. The results revealed that I-TiO2/PVC exhibit excellent photocatalytic antibacterial activity, which can destroy the propagation of the Escherichia coli and cause the deactivation and death of most E. coli bacteria within 30min visible light illumination. Clinical study on animals showed that I-TiO2 coated on PVC decrease the formation of biofilm on PVC surface in the mechanical ventilation. Furthermore, I-TiO2/PVC can effectively reduce inflammation of tracheal tissue of bam suckling pig and prevents the occurrence of VAP.

  5. 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

  6. Growth of epitaxial orthorhombic YO1.5-substituted HfO2 thin film

    Science.gov (United States)

    Shimizu, Takao; Katayama, Kiliha; Kiguchi, Takanori; Akama, Akihiro; Konno, Toyohiko J.; Funakubo, Hiroshi

    2015-07-01

    YO1.5-substituted HfO2 thin films with various substitution amounts were grown on (100) YSZ substrates by the pulsed laser deposition method directly from the vapor phase. The epitaxial growth of film with different YO1.5 amounts was confirmed by the X-ray diffraction method. Wide-area reciprocal lattice mapping measurements were performed to clarify the crystal symmetry of films. The formed phases changed from low-symmetry monoclinic baddeleyite to high-symmetry tetragonal/cubic fluorite phases through an orthorhombic phase as the YO1.5 amount increased from 0 to 0.15. The additional annular bright-field scanning transmission electron microscopy indicates that the orthorhombic phase has polar structure. This means that the direct growth by vapor is of polar orthorhombic HfO2-based film. Moreover, high-temperature X-ray diffraction measurements showed that the film with a YO1.5 amount of 0.07 with orthorhombic structure at room temperature only exhibited a structural phase transition to tetragonal phase above 450 °C. This temperature is much higher than the reported maximum temperature of 200 °C to obtain ferroelectricity as well as the expected temperature for real device application. The growth of epitaxial orthorhombic HfO2-based film helps clarify the nature of ferroelectricity in HfO2-based films (186 words/200 words).

  7. Fabrication and Surface Properties of Composite Films of SAM/Pt/ZnO/SiO 2

    KAUST Repository

    Yao, Ke Xin

    2008-12-16

    Through synthetic architecture and functionalization with self-assembled monolayers (SAMs), complex nanocomposite films of SAM/Pt/ZnO/SiO2 have been facilely prepared in this work. The nanostructured films are highly uniform and porous, showing a wide range of tunable wettabilities from superhydrophilicity to superhydrophobicity (water contact angles: 0° to 170°). Our approach offers synthetic flexibility in controlling film architecture, surface topography, coating texture, crystallite size, and chemical composition of modifiers (e.g., SAMs derived from alkanethiols). For example, wettability properties of the nanocomposite films can be finely tuned with both inorganic phase (i.e., ZnO/SiO2 and Pt/ZnO/SiO2) and organic phase (i.e., SAMs on Pt/ZnO/SiO2). Due to the presence of catalytic components Pt/ZnO within the nanocomposites, surface reactions of the organic modifiers can further take place at room temperature and elevated temperatures, which provides a means for SAM formation and elimination. Because the Pt/ZnO forms an excellent pair of metal-semiconductors for photocatalysis, the anchored SAMs can also be modified or depleted by UV irradiation (i.e., the films possess self-cleaning ability). Potential applications of these nanocomposite films have been addressed. Our durability tests also confirm that the films are thermally stable and structurally robust in modification- regeneration cycles. © 2008 American Chemical Society.

  8. Fabrication and photoelectrochemical properties of ZnS/Au/TiO2 nanotube array films.

    Science.gov (United States)

    Zhu, Yan-Feng; Zhang, Juan; Xu, Lu; Guo, Ya; Wang, Xiao-Ping; Du, Rong-Gui; Lin, Chang-Jian

    2013-03-21

    A highly ordered TiO(2) nanotube array film was fabricated by an anodic oxidation method. The film was modified by Au nanoparticles (NPs) formed by a deposition-precipitation technique and was covered with a thin ZnS shell prepared by a successive ionic layer adsorption and reaction (SILAR) method. The photoelectrochemical properties of the prepared ZnS/Au/TiO(2) composite film were evaluated by incident photon-to-current conversion efficiency (IPCE), and photopotential and electrochemical impedance spectroscopy (EIS) measurements under white light illumination. The results indicated that the Au NPs could expand the light sensitivity range of the film and suppress the electron-hole recombination, and the ZnS shell could inhibit the leakage of photogenerated electrons from the surface of Au NPs to the ZnS/electrolyte interface. When the 403 stainless steel in a 0.5 M NaCl solution was coupled to the ZnS/Au/TiO(2) nanotube film photoanode under illumination, its potential decreased by 400 mV, showing that the composite film had a better photocathodic protection effect on the steel than that of a pure TiO(2) nanotube film.

  9. 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.

  10. 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

  11. 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...

  12. 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 ...

  13. Ultrathin Hf0.5Zr0.5O2 Ferroelectric Films on Si.

    Science.gov (United States)

    Chernikova, Anna; Kozodaev, Maksim; Markeev, Andrei; Negrov, Dmitrii; Spiridonov, Maksim; Zarubin, Sergei; Bak, Ohheum; Buragohain, Pratyush; Lu, Haidong; Suvorova, Elena; Gruverman, Alexei; Zenkevich, Andrei

    2016-03-23

    Because of their immense scalability and manufacturability potential, the HfO2-based ferroelectric films attract significant attention as strong candidates for application in ferroelectric memories and related electronic devices. Here, we report the ferroelectric behavior of ultrathin Hf0.5Zr0.5O2 films, with the thickness of just 2.5 nm, which makes them suitable for use in ferroelectric tunnel junctions, thereby further expanding the area of their practical application. Transmission electron microscopy and electron diffraction analysis of the films grown on highly doped Si substrates confirms formation of the fully crystalline non-centrosymmetric orthorhombic phase responsible for ferroelectricity in Hf0.5Zr0.5O2. Piezoresponse force microscopy and pulsed switching testing performed on the deposited top TiN electrodes provide further evidence of the ferroelectric behavior of the Hf0.5Zr0.5O2 films. The electronic band lineup at the top TiN/Hf0.5Zr0.5O2 interface and band bending at the adjacent n(+)-Si bottom layer attributed to the polarization charges in Hf0.5Zr0.5O2 have been determined using in situ X-ray photoelectron spectroscopy analysis. The obtained results represent a significant step toward the experimental implementation of Si-based ferroelectric tunnel junctions.

  14. Dissociations of O2 molecules on ultrathin Pb(111)films: first-principles plane wave calculations

    Institute of Scientific and Technical Information of China (English)

    Hu Zi-Yu; Yang Yu; Sun Bo; Zhang Ping; Wang Wen-Chuan; Shao Xiao-Hong

    2012-01-01

    Using first-principles calculations,we systematically study the dissociations of O2 molecules on different ultrathin Pb(111) films.According to our previous work revealing the molecular adsorption precursor states for O2,we further explore why there are two nearly degenerate adsorption states on Pb(111) ultrathin films,but no precursor adsorption states existing at all on Mg(0001) and Al(111) surfaces.The reason is concluded to be the different surface electronic structures.For the O2 dissociation,we consider both the reaction channels from gas-like and molecularly adsorbed O2 molecules.We find that the energy barrier for O2 dissociation from the molecular adsorption precursor states is always smaller than that from O2 gas.The most energetically favorable dissociation process is found to be the same on different Pb(111) films,and the energy barriers are found to be influenced by the quantum size effects of Pb(111) films.

  15. 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.

  16. Preparation of TiO2/Ag/TiO2 (TAT) multilayer films with optical and electrical properties enhanced by using Cr-added Ag film

    Science.gov (United States)

    Loka, Chadrasekhar; Lee, Kee-Sun

    2017-09-01

    The dielectric-metal-dielectric tri-layer films have attracted much attention by virtue of their low-cost and high quality device performance as a transparent conductive electrode. Here, we report the deposition of Cr doped Ag films sandwiched between thin TiO2 layers and investigation on the surface microstructure, optical and electrical properties depending on the thickness of the Ag(Cr). The activation energy (1.18 eV) for grain growth of Ag was calculated from the Arrhenius plot using the law Dn -D0n = kt , which was comparable to the bulk diffusion of Ag. This result indicated the grain growth of Ag was effectively retarded by the Cr addition, which was presumed to related with blocking the surface and grain boundary diffusion due to Cr segregation. Based on thermal stability of Cr added Ag film, we deposited TiO2/Ag(Cr)/TiO2 (TAT) multilayer thin films and with a 10 nm thick Ag(Cr), the TAT films showed high optical transmittance in the visible region (94.2%), low electrical resistivity (8.66 × 10-5 Ω cm), and hence the high figure of merit 57.15 × 10-3 Ω-1 was achieved. The high transmittance of the TAT film was believed to be attributed to the low optical loss due to a reduction in the Ag layer thickness, the surface plasmon effect, and the electron scattering reduced by the Ag layer with a low electrical resistivity.

  17. Mixed Al and Si doping in ferroelectric HfO2 thin films

    Science.gov (United States)

    Lomenzo, Patrick D.; Takmeel, Qanit; Zhou, Chuanzhen; Chung, Ching-Chang; Moghaddam, Saeed; Jones, Jacob L.; Nishida, Toshikazu

    2015-12-01

    Ferroelectric HfO2 thin films 10 nm thick are simultaneously doped with Al and Si. The arrangement of the Al and Si dopant layers within the HfO2 greatly influences the resulting ferroelectric properties of the polycrystalline thin films. Optimizing the order of the Si and Al dopant layers led to a remanent polarization of ˜20 μC/cm2 and a coercive field strength of ˜1.2 MV/cm. Post-metallization anneal temperatures from 700 °C to 900 °C were used to crystallize the Al and Si doped HfO2 thin films. Grazing incidence x-ray diffraction detected differences in peak broadening between the mixed Al and Si doped HfO2 thin films, indicating that strain may influence the formation of the ferroelectric phase with variations in the dopant layering. Endurance characteristics show that the mixed Al and Si doped HfO2 thin films exhibit a remanent polarization greater than 15 μC/cm2 up to 108 cycles.

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

    Science.gov (United States)

    Wang, Xuemin; Hou, Xinggang; Luan, Weijiang; Li, Dejun; Yao, Kun

    2012-08-01

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

  19. 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.

  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. 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.

  2. 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.

  3. Humidity sensing properties of La~(3+)/Ce~(3+)-doped TiO_2-20 wt.% SnO_2 thin films derived from sol-gel method

    Institute of Scientific and Technical Information of China (English)

    李红霞; 史志铭; 刘红伟

    2010-01-01

    The humidity sensing properties of La3+/Ce3+-doped TiO2-20 wt.%SnO2 thin films were studied.Sol-gel method was employed to prepare the films on alumina substrates.By constructing a humidity-impedance measuring system,the sensing behaviors were inspected for the films sintered at different temperatures.Experimental results showed that,0.5 wt.% of La2O3 or Ce2O3 doped films sintered at 500 °C for 2 h had the best humidity sensing properties,the impedance decreasing from 109 ? to below 104 ? in the humidity ra...

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  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. Wet chemical methods for producing mixing crystalline phase ZrO2 thin film

    Science.gov (United States)

    Pakma, Osman; Özdemir, Cengiz; Kariper, İ. Afşin; Özaydın, Cihat; Güllü, Ömer

    2016-07-01

    The aim of the study is to develop a more economical and easier method for obtaining ZrO2 thin films at lower temperature, unlike the ones mentioned in the literature. For this purpose, wet chemical synthesis methods have been tested and XRD, UV-VIS and SEM analysis of ZrO2 thin films have been performed. At the end of the analysis, we identified the best method and it has been found that the features of the films produced with this method were better than the films produced by using different reagents, as well as the films reported in the literature. Especially it has been observed that the transmittance of the film produced with this method were higher and better than the films in the literature and the others. In addition, refractive index of the film produced with this method was observed to be lower. Moreover, by using the same method Al/ZrO2/p-Si structure has been obtained and it has been compared with Al/p-Si reference structure in terms of electrical parameters.

  11. 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.

  12. Preparation of sensitive and recyclable porous Ag/TiO2 composite films for SERS detection

    Science.gov (United States)

    Zhang, Zhengyi; Yu, Jiajie; Yang, Jingying; Lv, Xiang; Wang, Tianhe

    2015-12-01

    Porous Ag/TiO2 composite films were prepared by spin coating of titania on normal glass slides and subsequent photochemical deposition of silver nanoparticles (AgNPs). The films were characterized by XRD and FESEM to reveal micro structural and morphological differences between films obtained under varied conditions. The SERS properties of these films were investigated using aqueous crystal violet (CV) as probe molecules. The results indicate that the content of polyethylene glycol (PEG) and photo-reduction time had significant influences on both the microstructure and SERS performance of Ag/TiO2 films. The highest SERS sensitivity that allowed as low as 10-10 M aqueous CV to be detected, was achieved with the PEG/(C4H9O)4Ti molar ratio being 0.08% and with 30 min of UV irradiation. With this film a linear relationship was established through experiment between SERS intensity and CV concentration from 10-10 to 10-5 M, which could be used as a calibration curve for CV concentration measurement. In addition, the film could be reused as a SERS substrate for up to four times without significantly losing SERS sensitivity if a simple regeneration was followed. It is visualized that the Ag/TiO2 film on glass has potentials for being developed into a practical SERS substrate with high sensitivity and good reusability.

  13. 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.

  14. 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.

  15. 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 %.

  16. Facile strategy and mechanism for orthorhombic SnO2 thin films

    Science.gov (United States)

    Chen, Zhiwen; Lai, Joseph K. L.; Shek, Chan-Hung

    2006-12-01

    Orthorhombic phase SnO2 is a material with unknown optical, electrical, and gas-sensing properties. It was found previously only at high pressures and temperatures. A facile strategy for the synthesis of orthorhombic SnO2 is of fundamental importance. Using pulsed-laser deposition, the authors report a kind of experimental realization of a pure orthorhombic SnO2 thin film under low pressure and temperature that are much lower than those of traditional methods. The optical properties of an orthorhombic SnO2 thin film were measured by spectrophotometric transmittance. The oxygen exchange reaction mechanism at the grain interfaces was proposed to explain the formation and optical properties of this orthorhombic phase.

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

    Science.gov (United States)

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

    2015-04-01

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

  19. 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.

  20. 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.

  1. Improved Performance for Dye-Sensitized Solar Cells Using a Compact TiO2 Layer Grown by Sputtering

    OpenAIRE

    Hung-Chih Chang; Ming-Jenq Twu; Chun-Yao Hsu; Ray-Quen Hsu; Chin-Guo Kuo

    2014-01-01

    This work determines the effect of compact TiO2 layers that are deposited onto fluorine-doped tin oxide (FTO), to improve the performance of dye-sensitized solar cells (DSSC). A series of compact TiO2 layers are prepared using radio frequency (rf) reactive magnetron sputtering. The films are characterized using X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), and UV-Vis spectroscopy. The results show that when the Ar/O2/N2 flow rates are 36 : 18 : 9,...

  2. 不同基底上HfO2/SiO2多层膜的力学性能%Mechanical Properties of HfO2/SiO2 Thin Films on Different Substrates

    Institute of Scientific and Technical Information of China (English)

    王河; 贺洪波; 张伟丽

    2013-01-01

    The HfO2/SiO2 films are deposited on K9 glass and Y3Al5O12 (YAG) crystal substrates by electron beam technology respectively.Nano-scratch tests are taken to investigate the mechanical properties of films respectively.The results show that the modulus of the films deposited on K9 and YAG are 34.8 GPa and 38.5 GPa respectively and the substrates have few effect on the elasticity modulus of the films.The adhesive force of the film is 7 mN on K9 substrate and 5 mN on YAG,and they present different failure modes.This can be attributed to the weak adhesion and large divergence of modulus between film and YAG crystal.The chemical binding state and elasticity modulus between the film and the substrate are taken to explain the different mechanical behaviors of the films on YAG and K9 substrates.%用电子束蒸发技术在K9玻璃及YAG晶体上沉积了HfO2/SiO2多层膜,采用纳米划痕仪对薄膜的力学性能进行了研究.实验结果表明:沉积在YAG和K9的多层膜弹性模量分别为34.8 GPa和38.5 GPa,基底对薄膜的弹性模量影响较小;YAG和K9上薄膜的粘附失效临界附着力分别为5 mN和7 mN,薄膜与YAG基底的结合状态较K9基底的差,并且呈现不同破坏模式.从薄膜之间及膜基界面处的界面结合状态和弹性模量两方面分析解释了YAG基底和K9基底上薄膜的不同力学行为.

  3. Endurance and Cycle-to-cycle Uniformity Improvement in Tri-Layered CeO2/Ti/CeO2 Resistive Switching Devices by Changing Top Electrode Material

    Science.gov (United States)

    Rana, Anwar Manzoor; Akbar, Tahira; Ismail, Muhammad; Ahmad, Ejaz; Hussain, Fayyaz; Talib, Ijaz; Imran, Muhammad; Mehmood, Khalid; Iqbal, Khalid; Nadeem, M. Younus

    2017-01-01

    Resistance switching characteristics of CeO2/Ti/CeO2 tri-layered films sandwiched between Pt bottom electrode and two different top electrodes (Ti and TaN) with different work functions have been investigated. RRAM memory cells composed of TaN/CeO2/Ti/CeO2/Pt reveal better resistive switching performance instead of Ti/CeO2/Ti/CeO2/Pt memory stacks. As compared to the Ti/CeO2 interface, much better ability of TaN/CeO2 interface to store and exchange plays a key role in the RS performance improvement, including lower forming/SET voltages, large memory window (~102) and no significant data degradation during endurance test of >104 switching cycles. The formation of TaON thinner interfacial layer between TaN TE and CeO2 film is found to be accountable for improved resistance switching behavior. Partial charge density of states is analyzed using density functional theory. It is found that the conductive filaments formed in CeO2 based devices is assisted by interstitial Ti dopant. Better stability and reproducibility in cycle-to-cycle (C2C) resistance distribution and Vset/Vreset uniformity were achieved due to the modulation of current conduction mechanism from Ohmic in low field region to Schottky emission in high field region. PMID:28079056

  4. Endurance and Cycle-to-cycle Uniformity Improvement in Tri-Layered CeO2/Ti/CeO2 Resistive Switching Devices by Changing Top Electrode Material

    Science.gov (United States)

    Rana, Anwar Manzoor; Akbar, Tahira; Ismail, Muhammad; Ahmad, Ejaz; Hussain, Fayyaz; Talib, Ijaz; Imran, Muhammad; Mehmood, Khalid; Iqbal, Khalid; Nadeem, M. Younus

    2017-01-01

    Resistance switching characteristics of CeO2/Ti/CeO2 tri-layered films sandwiched between Pt bottom electrode and two different top electrodes (Ti and TaN) with different work functions have been investigated. RRAM memory cells composed of TaN/CeO2/Ti/CeO2/Pt reveal better resistive switching performance instead of Ti/CeO2/Ti/CeO2/Pt memory stacks. As compared to the Ti/CeO2 interface, much better ability of TaN/CeO2 interface to store and exchange plays a key role in the RS performance improvement, including lower forming/SET voltages, large memory window (~102) and no significant data degradation during endurance test of >104 switching cycles. The formation of TaON thinner interfacial layer between TaN TE and CeO2 film is found to be accountable for improved resistance switching behavior. Partial charge density of states is analyzed using density functional theory. It is found that the conductive filaments formed in CeO2 based devices is assisted by interstitial Ti dopant. Better stability and reproducibility in cycle-to-cycle (C2C) resistance distribution and Vset/Vreset uniformity were achieved due to the modulation of current conduction mechanism from Ohmic in low field region to Schottky emission in high field region.

  5. Endurance and Cycle-to-cycle Uniformity Improvement in Tri-Layered CeO2/Ti/CeO2 Resistive Switching Devices by Changing Top Electrode Material.

    Science.gov (United States)

    Rana, Anwar Manzoor; Akbar, Tahira; Ismail, Muhammad; Ahmad, Ejaz; Hussain, Fayyaz; Talib, Ijaz; Imran, Muhammad; Mehmood, Khalid; Iqbal, Khalid; Nadeem, M Younus

    2017-01-12

    Resistance switching characteristics of CeO2/Ti/CeO2 tri-layered films sandwiched between Pt bottom electrode and two different top electrodes (Ti and TaN) with different work functions have been investigated. RRAM memory cells composed of TaN/CeO2/Ti/CeO2/Pt reveal better resistive switching performance instead of Ti/CeO2/Ti/CeO2/Pt memory stacks. As compared to the Ti/CeO2 interface, much better ability of TaN/CeO2 interface to store and exchange plays a key role in the RS performance improvement, including lower forming/SET voltages, large memory window (~10(2)) and no significant data degradation during endurance test of >10(4) switching cycles. The formation of TaON thinner interfacial layer between TaN TE and CeO2 film is found to be accountable for improved resistance switching behavior. Partial charge density of states is analyzed using density functional theory. It is found that the conductive filaments formed in CeO2 based devices is assisted by interstitial Ti dopant. Better stability and reproducibility in cycle-to-cycle (C2C) resistance distribution and Vset/Vreset uniformity were achieved due to the modulation of current conduction mechanism from Ohmic in low field region to Schottky emission in high field region.

  6. 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.

  7. Ion assisted deposition of SiO2 film from silicon

    Science.gov (United States)

    Pham, Tuan. H.; Dang, Cu. X.

    2005-09-01

    Silicon dioxide, SiO2, is one of the preferred low index materials for optical thin film technology. It is often deposited by electron beam evaporation source with less porosity and scattering, relatively durable and can have a good laser damage threshold. Beside these advantages the deposition of critical optical thin film stacks with silicon dioxide from an E-gun was severely limited by the stability of the evaporation pattern or angular distribution of the material. The even surface of SiO2 granules in crucible will tend to develop into groove and become deeper with the evaporation process. As the results, angular distribution of the evaporation vapor changes in non-predicted manner. This report presents our experiments to apply Ion Assisted Deposition process to evaporate silicon in a molten liquid form. By choosing appropriate process parameters we can get SiO2 film with good and stable property.

  8. 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.

  9. Electron radiation effects on time-dependent dielectric breakdown in SiO2 films

    Science.gov (United States)

    Li, S. P.; Maserjian, J.

    1975-01-01

    An experiment testing the effect of ionizing radiation on breakdown characteristics of SiO2 films is presented. Silicon wafers were oxidized and metallized, and a capacitor array was etched into a control sample while the rest were first irradiated with 1 MeV electrons and then etched. Time-dependent dielectric tests were made on all the capacitors, and the average characteristics of 96 capacitors are illustrated graphically. The curves are consistent with the model of holes trapped in the SiO2 film during irradiation leading to a retarding field for positive ion emission and drift toward the interface. It is shown how an externally applied field is reduced by the trapped charge, and that changes in the dielectric breakdown properties of the SiO2 film after irradiation depend on the positive trapped charge near the metal interface.

  10. Nanoporous SiO2 thin films made by atomic layer deposition and atomic etching

    Science.gov (United States)

    Ghazaryan, Lilit; Kley, E.-Bernhard; Tünnermann, Andreas; Szeghalmi, Adriana

    2016-06-01

    A new route to prepare nanoporous SiO2 films by mixing atomic-layer-deposited alumina and silica in an Å-scale is presented. The selective removal of Al2O3 from the composites using wet chemical etching with phosphoric acid resulted in nanoporous thin SiO2 layers. A diffusion-controlled dissolution mechanism is identified whereby an interesting reorganization of the residual SiO2 is observed. The atomic scale oxide mixing is decisive in attaining and tailoring the film porosity. The porosity and the refractive index of nanoporous silica films were tailored from 9% to 69% and from 1.40 to 1.13, respectively. The nanoporous silica was successfully employed as antireflection coatings and as diffusion membranes to encapsulate nanostructures.

  11. The influence of methanol addition during the film growth of SnO 2 by atmospheric pressure chemical vapor deposition

    NARCIS (Netherlands)

    Volintiru, I.; Graaf, A. de; Deelen, J. van; Poodt, P.W.G.

    2011-01-01

    Undoped tin oxide (SnO2) thin films have been deposited in a stagnant point flow chemical vapor deposition reactor from a water/tin tetrachloride mixture. By adding methanol during the deposition process the film electrical properties change significantly: ten times more conductive SnO 2 films are o

  12. Effect of Silver Deposition on Photocatalytic Performance of N-Doped TiO2 Thin Film%Ag负载对N掺杂TiO2薄膜光催化性能的影响

    Institute of Scientific and Technical Information of China (English)

    张伟华; 李秀燕; 落全伟; 刘瑞萍; 曹铃; 范明明

    2016-01-01

    采用电泳沉积法在 Ti 片上制备 TiN 薄膜,在450℃下保温60 min 制备 N 掺杂 TiO2薄膜(N-TiO2薄膜),然后在不同浓度的 AgNO3溶液中利用光还原沉积法制备负载 Ag 的 N-TiO2薄膜。利用 X 射线衍射(XRD)、扫描电子显微镜(SEM)和紫外-可见吸收光谱(UV-Vis)对薄膜进行表征,通过测试瞬态光电流密度研究薄膜的光电性能,并以罗丹明 B 为降解目标物评价薄膜的光催化活性,重点研究了负载 Ag 对 N-TiO2薄膜光电和光催化性能的影响规律。结果表明:Ag-NO3溶液浓度为0.05 mol·L-1时,Ag 的负载量最为适宜,N-TiO2薄膜的光电及光催化性能最佳;负载 Ag 的 N-TiO2薄膜在可见光下的瞬态光电流密度约为 N-TiO2薄膜的5.4倍;负载 Ag 显著提高了 N-TiO2薄膜的光催化性能,经过可见光照射180 min 后,薄膜对罗丹明 B 的降解率达到98%。%Titanium nitride (TiN)thin film was prepared by electrophoreic deposition process on Ti substrate in an aqueous suspension of nanosized TiN powder,and then nitrogen-doped tita-nium dioxide (N-TiO2 )thin film was fabricated by heating the TiN film at 450 ℃ for 1h in air. Ag nanoparticles were deposited on the surface of N-TiO2 thin film in different concentration of AgNO3 solution by photo-reduction deposition.The samples were characterized by X-ray diffrac-tion,scanning electron microscopy and UV-visible spectroscopy.Photoelectric properties and pho-tocatalytic activities were investigated via the measurement of transient photocurrent density and the photocatalytic degradation of Rhodamine B under visible light,respectively.Effect of silver deposition on photoelectric and photocatalytic performance of N-TiO2 thin film was emphatically studied.The results show that moderate deposition of Ag particles significantly improved the photoelectric and photocatalytic performance of N-TiO2 thin film,and the optimal concentration of AgNO3 solution for Ag deposition was 0.05 mol·L-1 .Under

  13. Synthesis of Ag-TiO2 composite nano thin film for antimicrobial application.

    Science.gov (United States)

    Yu, Binyu; Leung, Kar Man; Guo, Qiuquan; Lau, Woon Ming; Yang, Jun

    2011-03-18

    TiO2 photocatalysts have been found to kill cancer cells, bacteria and viruses under mild UV illumination, which offers numerous potential applications. On the other hand, Ag has long been proved as a good antibacterial material as well. The advantage of Ag-TiO2 nanocomposite is to expand the nanomaterial's antibacterial function to a broader range of working conditions. In this study neat TiO2 and Ag-TiO2 composite nanofilms were successfully prepared on silicon wafer via the sol-gel method by the spin-coating technique. The as-prepared composite Ag-TiO2 and TiO2 films with different silver content were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS) to determine the topologies, microstructures and chemical compositions, respectively. It was found that the silver nanoparticles were uniformly distributed and strongly attached to the mesoporous TiO2 matrix. The morphology of the composite film could be controlled by simply tuning the molar ratio of the silver nitrate aqueous solution. XPS results confirmed that the Ag was in the Ag(0) state. The antimicrobial effect of the synthesized nanofilms was carried out against gram-negative bacteria (Escherichia coli ATCC 29425) by using an 8 W UV lamp with a constant relative intensity of 0.6 mW cm(-2) and in the dark respectively. The synthesized Ag-TiO2 thin films showed enhanced bactericidal activities compared to the neat TiO2 nanofilm both in the dark and under UV illumination.

  14. Synthesis of Ag-TiO2 composite nano thin film for antimicrobial application

    Science.gov (United States)

    Yu, Binyu; Leung, Kar Man; Guo, Qiuquan; Lau, Woon Ming; Yang, Jun

    2011-03-01

    TiO2 photocatalysts have been found to kill cancer cells, bacteria and viruses under mild UV illumination, which offers numerous potential applications. On the other hand, Ag has long been proved as a good antibacterial material as well. The advantage of Ag-TiO2 nanocomposite is to expand the nanomaterial's antibacterial function to a broader range of working conditions. In this study neat TiO2 and Ag-TiO2 composite nanofilms were successfully prepared on silicon wafer via the sol-gel method by the spin-coating technique. The as-prepared composite Ag-TiO2 and TiO2 films with different silver content were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS) to determine the topologies, microstructures and chemical compositions, respectively. It was found that the silver nanoparticles were uniformly distributed and strongly attached to the mesoporous TiO2 matrix. The morphology of the composite film could be controlled by simply tuning the molar ratio of the silver nitrate aqueous solution. XPS results confirmed that the Ag was in the Ag0 state. The antimicrobial effect of the synthesized nanofilms was carried out against gram-negative bacteria (Escherichia coli ATCC 29425) by using an 8 W UV lamp with a constant relative intensity of 0.6 mW cm - 2 and in the dark respectively. The synthesized Ag-TiO2 thin films showed enhanced bactericidal activities compared to the neat TiO2 nanofilm both in the dark and under UV illumination.

  15. Morphological and photoelectrochemical characterization of core-shell nanoparticle films for dye-sensitized solar cells: Zn-O type shell on SnO2 and TiO2 cores.

    Science.gov (United States)

    Park, N G; Kang, M G; Kim, K M; Ryu, K S; Chang, S H; Kim, D K; van de Lagemaat, J; Benkstein, K D; Frank, A J

    2004-05-11

    Core-shell type nanoparticles with SnO2 and TiO2 cores and zinc oxide shells were prepared and characterized by surface sensitive techniques. The influence of the structure of the ZnO shell and the morphology ofnanoparticle films on the performance was evaluated. X-ray absorption near-edge structure and extended X-ray absorption fine structure studies show the presence of thin ZnO-like shells around the nanoparticles at low Zn levels. In the case of SnO2 cores, ZnO nanocrystals are formed at high Zn/Sn ratios (ca. 0.5). Scanning electron microscopy studies show that Zn modification of SnO2 nanoparticles changes the film morphology from a compact mesoporous structure to a less dense macroporous structure. In contrast, Zn modification of TiO2 nanoparticles has no apparent influence on film morphology. For SnO2 cores, adding ZnO improves the solar cell efficiency by increasing light scattering and dye uptake and decreasing recombination. In contrast, adding a ZnO shell to the TiO2 core decreases the cell efficiency, largely owing to a loss of photocurrent resulting from slow electron transport associated with the buildup of the ZnO surface layer.

  16. 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.

  17. 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.

  18. 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.

  19. Sol-Gel Synthesis of TiO2/SiO2 and ZnO/SiO2 Composite Films and Evaluation of Their Photocatalytic Activity towards Methyl Green

    Directory of Open Access Journals (Sweden)

    V. L. Chandraboss

    2013-01-01

    Full Text Available The TiO2/SiO2 and ZnO/SiO2 composite films were prepared by sol-gel dip coating method. The surface morphology and crystal structure of thin films were characterized by means of scanning electron microscopy (SEM with elementary dispersive X-ray analysis (EDX and X-ray diffractometer (XRD. Optical properties of films have been investigated using ultraviolet and visible spectroscopy (UV-visible spectroscopy. The photocatalytic activity was established by testing the degradation and decolorization of methyl green (MG from aqueous solution with artificial UV-light.

  20. Impacts of SiO2 planarization on optical thin film properties and laser damage resistance

    Science.gov (United States)

    Day, T.; Wang, H.; Jankowska, E.; Reagan, B. A.; Rocca, J. J.; Stolz, C. J.; Mirkarimi, P.; Folta, J.; Roehling, J.; Markosyan, A.; Route, R. R.; Fejer, M. M.; Menoni, C. S.

    2016-12-01

    Lawrence Livermore National Laboratory (LLNL) and Colorado State University (CSU) have co-developed a planarization process to smooth nodular defects. This process consists of individually depositing then etching tens of nanometers of SiO2 with a ratio of 2:1, respectively. Previous work shows incorporating the angular dependent ion surface etching and unidirectional deposition reduces substrate defect cross-sectional area by 90%. This work investigates the micro-structural and optical modifications of planarized SiO2 films deposited by ion beam sputtering (IBS). It is shown the planarized SiO2 thin films have 3x increase in absorption and 18% reduction in thin film stress as compared to control (as deposited) SiO2. Planarized SiO2 films exhibit 13% increase in RMS surface roughness with respect to the control and super polished fused silica substrates. Laser-induced damage threshold (LIDT) results indicate the planarization process has no effect on the onset fluence but alters the shape of the probability vs fluence trace.

  1. 锌掺杂多孔SiO2/TiO2薄膜制备及光催化性能研究%Preparation of Zn-doped SiO2/TiO2 thin films by sol-gel processing and their photocatalytic properties

    Institute of Scientific and Technical Information of China (English)

    胡张顺; 姚伯龙; 鲍雪钦

    2013-01-01

    锌掺杂多孔SiO2/TiO2(多孔 Zn-SiO2/TiO2)复合薄膜自清洁玻璃以含聚乙二醇的钛醇盐和硅醇盐的复合溶胶前驱体通过浸渍提拉法制备.结果表明,在TiO2薄膜中添加SiO2可抑制TiO2晶粒长大,并提高TiO2薄膜的亲水性;随着聚乙二醇添加量的增加,锌掺杂多孔SiO2/TiO2薄膜的孔隙增多,表面积增大;经500℃煅烧的多孔Zn-SiO2/TiO2复合薄膜中,TiO2主要为催化效率高的锐钛矿相;多孔Zn-SiO2/TiO2复合薄膜表观光催化降解速率明显高于未掺锌多孔SiO2/TiO2薄膜.%The porous Zn-doped SiO2/TiO2(porous Zn-SiO2/TiO2) composite thin films on the glass substrate were prepared from alkoxide solutions containing polyethylene glycol(PEG) by sol-gel method. The results showed that the addition of SiO2 to TiO2 thin films can suppress the grain growth of TiO2 crystal in the TiO2 thin films, low the contact angle for water of TiO2 films; the pore size is adjusted by adding different amount of PEG, the anatase TiO2 can grow on the porous Zn-SiO2/TiO2 composite thin films at 500 ℃; studies of photocatalytic degradation show that the degradation rate of porous Zn-SiO2/TiO2 composite thin films were higher than that of un-doped porous SiO2/TiO2 composite thin films.

  2. Electroluminescence from Si/SiO2 films deposited on p-Si substrates

    Institute of Scientific and Technical Information of China (English)

    马书懿; 萧勇; 陈辉

    2002-01-01

    The structure of Au/Si/SiO2/p-Si has been fabricated using the magnetron sputtering technique. It has a verygood rectifying behaviour. Visible electroluminescence (EL) has been observed from the Au/Si/SiO2/p-Si structureat a forward bias of 5V or larger. A broad band with one peak around 650-660 nm appears in all the EL spectra ofthe structure. The effects of the thickness of the Si layer in the Si/SiO2 films and of the input electrical power on ELspectra are studied systematically.

  3. On the structural origins of ferroelectricity in HfO2 thin films

    Science.gov (United States)

    Sang, Xiahan; Grimley, Everett D.; Schenk, Tony; Schroeder, Uwe; LeBeau, James M.

    2015-04-01

    Here, we present a structural study on the origin of ferroelectricity in Gd doped HfO2 thin films. We apply aberration corrected high-angle annular dark-field scanning transmission electron microscopy to directly determine the underlying lattice type using projected atom positions and measured lattice parameters. Furthermore, we apply nanoscale electron diffraction methods to visualize the crystal symmetry elements. Combined, the experimental results provide unambiguous evidence for the existence of a non-centrosymmetric orthorhombic phase that can support spontaneous polarization, resolving the origin of ferroelectricity in HfO2 thin films.

  4. Influences of Annealing on Residual Stress and Structure of HfO2 Films

    Institute of Scientific and Technical Information of China (English)

    SHEN Yan-Ming; SHAO Shu-Ying; DENG Zhen-Xia; HE Hong-Bo; SHAO Jian-Da; FAN Zheng-Xiu

    2007-01-01

    HfO2 films are deposited on BK7 glass substrates by electron beam evaporation. The influences of annealing between 100℃ and 400℃ on residual stresses and structures of HfO2 films are studied. It is found that little differences of spectra, residual stresses and structures are obtained after annealing at lower temperatures. After annealing at higher temperatures, the spectra shift to short wavelength, the residual stress increases with the increasing annealing temperature. At the same time, the crystallite size increases and interplanar distance decreases. The variations of optical spectra and residual stress correspond to the evolutions of structures induced by annealing.

  5. Deposition of a thin film of TiOx from a titanium metal target as novel blocking layers at conducting glass/TiO2 interfaces in ionic liquid mesoscopic TiO2 dye-sensitized solar cells.

    Science.gov (United States)

    Xia, Jiangbin; Masaki, Naruhiko; Jiang, Kejian; Yanagida, Shozo

    2006-12-21

    In dye-sensitized TiO2 solar cells, charge recombination processes at interfaces between fluorine-doped tin oxide (FTO), TiO2, dye, and electrolyte play an important role in limiting the photon-to-electron conversion efficiency. From this point of view, a high work function material such as titanium deposited by sputtering on FTO has been investigated as an effective blocking layer for preventing electron leakage from FTO without influencing electron injection. X-ray photoelectron spectroscopy analysis indicates that different species of Ti (Ti4+, Ti3+, Ti2+, and a small amount of Ti0) exist on FTO. Electrochemical and photoelectrochemical measurements reveal that thin films of titanium species, expressed as TiOx, work as a compact blocking layer between FTO and TiO2 nanocrystaline film, improving Voc and the fill factor, finally giving a better conversion efficiency for dye-sensitized TiO2 solar cells with ionic liquid electrolytes.

  6. 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.

  7. THE PREPARATION AND STUDY ON THE NANO-TiO2/SILK FIBROIN COMPOSITE FILMS BY THE SOL-GEL METHOD

    Institute of Scientific and Technical Information of China (English)

    FENG Xinxing; CHEN Jianyong; YU Chunhua

    2006-01-01

    Based on the sol-gel technique using butyl titanate as oxide precursor, the regenerated SF (silk fibroin)/nano-TiO2 composite films were synthesized. Different amounts of butyl titanate to SF were used to verify this effect on the characteristics of the formed materials. Samples were characterized by thermogravimetric analysis, X-ray diffractometry, UV, AFM and FT-IR spectroscopy.The experimental results reveal that, compared to the pure silk fibroin films, the mechanical strength of these regenerated SF/nano-TiO2 composite films were increased and the dissolubility in water of SF/nano-TiO2 composite films in aqueous solution were decreased. The diameter of nano-TiO2 particle films was about 80nm through UV and AFM. The nano-TiO2 particles were well dispersed in the regenerated silk fibroin. It was found that the crystal structures of the composite films were transited from typical Silk Ⅰ to typical Silk Ⅱ by the XRD and FTIR. Furthermore, the crystallinity of the composite films was obviously improved. Through the TGA, it was demonstrated that the heat transition temperature of composite films was also enhanced.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  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. 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.

  14. Deposition of SiOx barrier films by O2/TMDSO RF-PECVD

    Institute of Scientific and Technical Information of China (English)

    Zhou Mei-Li; Fu Ya-Bo; Chen Qiang; Ge Yuan-Jing

    2007-01-01

    This paper reports that the SiOx barrier films are deposited on polyethylene terephthalate substrate by plasmaenhanced chemical vapour deposition (PECVD) for the application of transparent barrier packaging. The variations of O2/Tetramethyldisiloxane (TMDSO) ratio and input power in radio frequency (RF) plasma are carried out to optimize barrier properties of the SiOx coated film. The properties of the coatings are characterized by Fourier transform infrared,water wpour transmission rate (WVTR), oxygen transmission rate (OTR), and atomic force microscopy analysers. It is found that the O2/TMDSO ratio exceeding 2:1 and the input power over 200 W yield SiOx films with low carbon contents which can be good to the barrier (WVTR and OTR) properties of the SiOx coatings. Also, the film properties not only depend on oxygen concentration of the inlet gas mixtures and input power, but also relate to the surface morphology of the coating.

  15. 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.

  16. THz pulse generation using a contact grating device composed of TiO2/SiO2 thin films on LiNbO3 crystal

    Science.gov (United States)

    Yoshida, Fumiko; Nagashima, Keisuke; Tsubouchi, Masaaki; Maruyama, Momoko; Ochi, Yoshihiro

    2016-11-01

    We developed a new contact grating device for terahertz (THz) pulse generation by optical rectification. The device was made from polycrystalline rutile TiO2 thin film in the grating region and an amorphous SiO2 layer deposited on a Mg-doped LiNbO3 crystal. Our calculations indicated that the TiO2 grating on the SiO2 layer would yield an increase in diffraction efficiency of up to 0.69. The prepared TiO2 thin film had a sufficient laser induced damage threshold (140 GW/cm2) to enable effective THz pulse generation. Using a prototype device, we demonstrated THz pulse generation and investigated the phase-matching conditions experimentally.

  17. Comparative Study of Two Different TiO2 Film Sensors on Response to H2 under UV Light and Room Temperature

    Directory of Open Access Journals (Sweden)

    Xiaoying Peng

    2016-08-01

    Full Text Available An anatase TiO2 film sensor was prepared by a facile in-situ method on the interdigitated Au electrode deposited on the alumina substrate. The structure, morphology and the optical properties of the in-situ TiO2 film sensor were characterized by X-ray diffraction, Scanning Electron Microscopy, and UV-vis diffuse reflectance spectra. The photo-assisted gas sensitivities of the prepared film towards H2 gas were evaluated at room temperature in N2 and synthetic air atmospheres. As compared to TiO2 film sensor prepared by drop-coating method, this in-situ TiO2 film sensor exhibited a more compact structure composed of uniform TiO2 microspheres as well as a better gas sensitivity towards H2 under UV irradiation, especially in synthetic air. The photo-electrochemical measurements suggest that these improvements may be associated with the efficient charge transfer in the TiO2 interface induced by the TiO2 microsphere structure. This study might offer a feasible approach to develop photo-assisted gas sensors at ambient temperature.

  18. Comparative Study of Two Different TiO2 Film Sensors on Response to H2 under UV Light and Room Temperature

    Science.gov (United States)

    Peng, Xiaoying; Wang, Zhongming; Huang, Pan; Chen, Xun; Fu, Xianzhi; Dai, Wenxin

    2016-01-01

    An anatase TiO2 film sensor was prepared by a facile in-situ method on the interdigitated Au electrode deposited on the alumina substrate. The structure, morphology and the optical properties of the in-situ TiO2 film sensor were characterized by X-ray diffraction, Scanning Electron Microscopy, and UV-vis diffuse reflectance spectra. The photo-assisted gas sensitivities of the prepared film towards H2 gas were evaluated at room temperature in N2 and synthetic air atmospheres. As compared to TiO2 film sensor prepared by drop-coating method, this in-situ TiO2 film sensor exhibited a more compact structure composed of uniform TiO2 microspheres as well as a better gas sensitivity towards H2 under UV irradiation, especially in synthetic air. The photo-electrochemical measurements suggest that these improvements may be associated with the efficient charge transfer in the TiO2 interface induced by the TiO2 microsphere structure. This study might offer a feasible approach to develop photo-assisted gas sensors at ambient temperature. PMID:27509502

  19. Accelerated Stress Testing of Thin-Film Modules with SnO2:F Transparent Conductors

    Energy Technology Data Exchange (ETDEWEB)

    Osterwald, C. R.; McMahon, T. J.; del Cueto, J. A.; Adelstein, J.; Puett, J.

    2003-05-01

    This paper reviews a testing program conducted at NREL for the past two years that applied voltage, water vapor, and light stresses to thin-film photovoltaic (PV) modules with SnO2:F transparent conducting oxides (TCOs) deposited on soda-lime glass superstrates. Electrochemical corrosion at the glass-TCO interface was observed to result in delamination of the thin-film layers. Experimental testing was directed toward accelerating the corrosion and understanding the nature of the resulting damage.

  20. Preparation of N-Doped TiO2-ZrO2 Composite Films under Electric Field and Heat Treatment and Assessment of Their Removal of Methylene Blue from Solution

    Directory of Open Access Journals (Sweden)

    Lefu Mei

    2014-01-01

    Full Text Available TiO2-ZrO2 composite film with the grain size of 50 nm was synthesized by electric field and heat (EF&H treatments. Portions of O atoms in the TiO2 network structure were replaced by N atoms as revealed by X-ray photoelectron spectroscopy (XPS and X-ray diffraction (XRD analyses, suggesting formation of a nonstoichiometric compound TiO2-xNx on the composite film. The UV-Vis spectra of the film suggested that the visible light with wavelength of 550 nm could be absorbed for the N-doped composite film after EF&H treatment in comparison to a cutoff wavelength of 400 nm for the composite film without EF treatment. Photocatalytic experiments showed that the degradation rate of methylene blue by N-doped composite films increased significantly under visible light irradiation. The partial replacement of O by doped N played a very important role in narrowing the band gap and improving the visible light photocatalytic reactivity.

  1. Stably superhydrophobic (IL/TiO2)n hybrid films: Intelligent self-cleaning materials

    Science.gov (United States)

    Xin, Bingwei; Wang, Limei; Jia, Chunxiao

    2015-12-01

    Stably self-cleaning (IL/TiO2)n nanocomposites were prepared via electrostatic layer-by-layer (LbL) self-assembly technique. Positively charged [C12mim]Br and negatively charged TiO2 nanoparticles were alternatively adsorbed on the negative glass substrates to form (IL/TiO2)n layers. They were characterized by scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and UV-vis absorption spectroscopy. Under the synergistic action of ionic liquids and TiO2 P25, in which TiO2 nanoparticles provided surface roughness while [C12mim]Br acted as lower surface tension material, glass coated with 13 bilayers of [C12mim]Br/TiO2 film arrived to superhydrophobicity with 151.7 ± 2°. Owing to the photoresponsive and photocatalytic properties of TiO2, (IL/TiO2)n nanocomposites achieved the reversible superhydrophobic and superhydrophilic transition upon alternating UV irradiation and storage in the dark, and presented good performance for photocatalytic degradation of methyl orange with ultraviolet (UV) illumination. Significantly, they could be recycled for several times without obvious fatigue.

  2. Ferroelectricity and antiferroelectricity of doped thin HfO2-based films.

    Science.gov (United States)

    Park, Min Hyuk; Lee, Young Hwan; Kim, Han Joon; Kim, Yu Jin; Moon, Taehwan; Kim, Keum Do; Müller, Johannes; Kersch, Alfred; Schroeder, Uwe; Mikolajick, Thomas; Hwang, Cheol Seong

    2015-03-18

    The recent progress in ferroelectricity and antiferroelectricity in HfO2-based thin films is reported. Most ferroelectric thin film research focuses on perovskite structure materials, such as Pb(Zr,Ti)O3, BaTiO3, and SrBi2Ta2O9, which are considered to be feasible candidate materials for non-volatile semiconductor memory devices. However, these conventional ferroelectrics suffer from various problems including poor Si-compatibility, environmental issues related to Pb, large physical thickness, low resistance to hydrogen, and small bandgap. In 2011, ferroelectricity in Si-doped HfO2 thin films was first reported. Various dopants, such as Si, Zr, Al, Y, Gd, Sr, and La can induce ferro-electricity or antiferroelectricity in thin HfO2 films. They have large remanent polarization of up to 45 μC cm(-2), and their coercive field (≈1-2 MV cm(-1)) is larger than conventional ferroelectric films by approximately one order of magnitude. Furthermore, they can be extremely thin (5 eV). These differences are believed to overcome the barriers of conventional ferroelectrics in memory applications, including ferroelectric field-effect-transistors and three-dimensional capacitors. Moreover, the coupling of electric and thermal properties of the antiferroelectric thin films is expected to be useful for various applications, including energy harvesting/storage, solid-state-cooling, and infrared sensors.

  3. 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.

  4. 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.

  5. Highly Luminescent Hybrid SiO2-Coated CdTe Quantum Dots Retained Initial Photoluminescence Efficiency in Sol-Gel SiO2 Film.

    Science.gov (United States)

    Sun, Hongsheng; Xing, Yugui; Wu, Qinan; Yang, Ping

    2015-02-01

    A highly luminescent silica film was fabricated using tetraethyl orthosilicate (TEOS) and 3-aminopropyltrimethoxysilane (APS) through a controlled sol-gel reaction. The pre-hydrolysis of TEOS and APS which resulted in the mixture of TEOS and APS in a molecular level is a key for the formation of homogenous films. The aminopropyl groups in APS play an important role for obtaining homogeneous film with high photoluminescence (PL). Red-emitting hybrid SiO2-coated CdTe nano-crystals (NCs) were fabricated by a two-step synthesis including a thin SiO2 coating via a sol-gel process and a subsequent refluxing using green-emitting CdTe NCs. The hybrid SiO2-coated CdTe NCs were embedded in a functional SiO2 film via a two-step process including adding the NCs in SiO2 sol with a high viscosity and almost without ethanol and a subsequent spinning coating. The hybrid SiO2-coated CdTe NCs retained their initial PL efficiency (54%) in the film. Being encapsulated with the hybrid NCs in the film, no change on the absorption and PL spectra of red-emitting CdTe NCs (632 nm) was observed. This indicates the hybrid NCs is stable enough during preparation. This phenomenon is ascribed to the controlled sol-gel process and a hybrid SiO2 shell on CdTe NCs. Because these films exhibited high PL efficiency and stability, they will be utilizable for potential applications in many fields.

  6. Effect of O2 plasma treatment on density-of-states in a-IGZO thin film transistors

    Science.gov (United States)

    Ding, Xingwei; Huang, Fei; Li, Sheng; Zhang, Jianhua; Jiang, Xueyin; Zhang, Zhilin

    2017-01-01

    This work reports an efficient route for enhancing the performance of amorphous InGaZnO (a-IGZO) thin film transistors (TFT). The mobility was greatly improved by about 38% by means of O2 plasma treatment. Temperature-stress was carried out to investigate the stability and extract the parameters related to activation energy ( E a) and density-of-states (DOS). The DOS was calculated on the basis of the experimentally obtained E a, which can explain the experimental observation. A lower activation energy ( E a, 0.72 eV) and a smaller DOS were obtained in the O2 plasma treatment TFT based on the temperature-dependent transfer curves. The results showed that temperature stability and electrical properties enhancements in a-IGZO thin film transistors were attributed to the smaller DOS. [Figure not available: see fulltext.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Monomeric malonate precursors for the MOCVD of HfO2 and ZrO2 thin films.

    Science.gov (United States)

    Pothiraja, Ramasamy; Milanov, Andrian; Parala, Harish; Winter, Manuela; Fischer, Roland A; Devi, Anjana

    2009-01-28

    New Hf and Zr malonate complexes have been synthesized by the reaction of metal amides with different malonate ligands (L = dimethyl malonate (Hdmml), diethyl malonate (Hdeml), di-tert-butyl malonate (Hdbml) and bis(trimethylsilyl) malonate (Hbsml)). Homoleptic eight-coordinated monomeric compounds of the type ML4 were obtained for Hf with all the malonate ligands employed. In contrast, for Zr only Hdmml and Hdeml yielded the eight-coordinated monomeric compounds of the type ML4, while using the bulky Hdbml and Hbsml ligands resulted into mixed alkoxo-malonato six-coordinated compounds of the type [ML2(OR)2]. Single crystal X-ray diffraction studies of all the compounds are presented and discussed, and they are found to be monomeric. The complexes are solids and in solution, they retain their monomeric nature as evidenced by NMR measurements. Compared to the classical beta-diketonate complexes, [M(acac)4] and [M(thd)4] (M = Hf, Zr; acac: acetylacetonate; thd: tetramethylheptadione), the new malonate compounds are more volatile, decompose at lower temperatures and have lower melting points. In particular, the homoleptic diethyl malonate complexes of Hf and Zr melt at temperatures as low as 62 degrees C. In addition, the compounds are very stable in air and can be sublimed quantitatively. The promising thermal properties makes these compounds interesting for metal-organic chemical vapor deposition (MOCVD). This was demonstrated by depositing HfO2 and ZrO2 thin films successfully with two representative Hf and Zr complexes.

  12. Synthesis, Characterization and Catalytic Properties of Attapulgite/CeO2 Nanocomposite Films for Decomposition of Rhodamine B.

    Science.gov (United States)

    Lu, Xiaowang; Li, Xiazhang; Qian, Junchao; Chen, Feng; Chen, Zhigang

    2015-08-01

    ATP(attapulgite)/CeO2 nanocomposite films were prepared on the glass substrates via a sol-gel and dip-coating route. The ATP/CeO2 nanocomposite films were characterized by Powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS), transmission electron microscopy (TEM), atomic force microscopy (AFM) and fourier transform infrared spectroscopy (FT-IR). The results showed that the ATP/CeO2 nanocomposite films were free from cracks and the nanoparticles were attached onto the surface of attapulgite. The ATP/CeO2 nanocomposite films displayed excellent catalytic activity for decomposition of Rhodamine B. The COD (chemical oxygen demand) removal rate of rhodamine B using ATP/CeO2 nanocomposite films as catalyst reached as high as 94% when the weight ratio of ATP to CeO2 was 2:1.

  13. Surface Structure and Photocatalytic Activity of Nano-TiO2 Thin Film

    Science.gov (United States)

    Controlled titanium dioxide (TiO2) thin films were deposited on stainless steel surfaces using flame aerosol synthetic technique, which is a one-step coating process, that doesn’t require further calcination. Solid state characterization of the coatings was conducted by different...

  14. 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.

  15. Epitaxial Cubic Ce2O3 Films via Ce-CeO2 Interfacial Reaction.

    Science.gov (United States)

    Stetsovych, Vitalii; Pagliuca, Federico; Dvořák, Filip; Duchoň, Tomáš; Vorokhta, Mykhailo; Aulická, Marie; Lachnitt, Jan; Schernich, Stefan; Matolínová, Iva; Veltruská, Kateřina; Skála, Tomáš; Mazur, Daniel; Mysliveček, Josef; Libuda, Jörg; Matolín, Vladimír

    2013-03-21

    Thin films of reduced ceria supported on metals are often applied as substrates in model studies of the chemical reactivity of ceria based catalysts. Of special interest are the properties of oxygen vacancies in ceria. However, thin films of ceria prepared by established methods become increasingly disordered as the concentration of vacancies increases. Here, we propose an alternative method for preparing ordered reduced ceria films based on the physical vapor deposition and interfacial reaction of Ce with CeO2 films. The method yields bulk-truncated layers of cubic c-Ce2O3. Compared to CeO2 these layers contain 25% of perfectly ordered vacancies in the surface and subsurface allowing well-defined measurements of the properties of ceria in the limit of extreme reduction. Experimentally, c-Ce2O3(111) layers are easily identified by a characteristic 4 × 4 surface reconstruction with respect to CeO2(111). In addition, c-Ce2O3 layers represent an experimental realization of a normally unstable polymorph of Ce2O3. During interfacial reaction, c-Ce2O3 nucleates on the interface between CeO2 buffer and Ce overlayer and is further stabilized most likely by the tetragonal distortion of the ceria layers on Cu. The characteristic kinetics of the metal-oxide interfacial reactions may represent a vehicle for making other metastable oxide structures experimentally available.

  16. Femtosecond Nonlinear Birefringence and Dichroism in Au:TiO_2 Composite Films

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Au:TiO2 nanocomposite film was fabricated by rf-sputtering. Both real and imaginary parts of x(3) were investigated by optical Kerr effect and pump-probe methods with femtosecond pulse with values of about 10-8 esu.

  17. Synthesis of crystalline Ge nanoclusters in PE-CVD-deposited SiO2 films

    DEFF Research Database (Denmark)

    Leervad Pedersen, T.P.; Skov Jensen, J.; Chevallier, J.

    2005-01-01

    The synthesis of evenly distributed Ge nanoclusters in plasma-enhanced chemical-vapour-deposited (PE-CVD) SiO2 thin films containing 8 at. % Ge is reported. This is of importance for the application of nanoclusters in semiconductor technology. The average diameter of the Ge nanoclusters can...

  18. Crystal structure and band gap determination of HfO2 thin films

    NARCIS (Netherlands)

    Cheynet, M.C.; Pokrant, S.; Tichelaar, F.D.; Rouvière, J.L.

    2007-01-01

    Valence electron energy loss spectroscopy (VEELS) and high resolution transmission electron microscopy (HRTEM) are performed on three different HfO2 thin films grown on Si (001) by chemical vapor deposition (CVD) or atomic layer deposition (ALD). For each sample the band gap (Eg) is determined by

  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. 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.

  1. Facile fabrication of transparent, broadband photoresponse, self-cleaning multifunctional graphene-TiO2 hybrid films.

    Science.gov (United States)

    Zhu, Jiayi; Cao, Yang; He, Junhui

    2014-04-15

    We reported a novel approach to fabricate graphene-TiO2 hybrid films by combination of the layer-by-layer (LbL) assembly and the surface sol-gel (SSG) process. The reduced graphene oxide (RGO) nanosheets and films were characterized by means of transmission electron microscopy, Raman spectroscopy, UV-visible absorbance spectroscopy, contact angle/interface system, and four-point probe. It was found that the graphene-TiO2 hybrid film showed enhanced photoresponse performance compared with RGO thin film and TiO2 thin film. The photoresponse properties of hybrid films could be manipulated by variation of the cycle numbers of RGO LbL assembly and titanium precursor SSG process. Photoinduced superhydrophility of the hybrid film was shown under broadband light illumination. The obtained transparent, superhydrophilic and conductive graphene-TiO2 hybrid film showed excellent photoresponse, antifogging, and antistatic behaviors.

  2. High-removal selectivity through interaction between polyacrylamide and SiO2 film in poly isolation chemical mechanical planarization.

    Science.gov (United States)

    Kim, Ye-Hwan; Lee, Kee-June; Park, Jea-Gun; Paik, Ungyu

    2009-06-01

    The interaction between polyacrylamide (PAM) and SiO2 film was investigated in order to elucidate the removal polycrystalline silicon (poly Si) to SiO2 selectivity in poly isolation chemical mechanical planarization (CMP). The hydrophilic characteristics of poly Si and SiO2 were analyzed by the X-ray photoelectron spectroscopy (XPS) and contact angle measurement. The surface of SiO2 is more hydrophilic than that of poly Si due to the siloxane (triple bond Si-O-Si triple bond) bonding. The adsorption behavior of PAM on poly Si and SiO2 film was determined by adsorption isotherms and force measurements using atomic force microscopy (AFM). Interaction between siloxane bonding of SiO2 film and the amine group along the backbone of PAM results in the adsorption of PAM on SiO2 film. Consequently, the passivation layer of PAM on the SiO2 film prevented abrasives from approaching the surface of SiO2 film, which led to suppression of the removal rate of SiO2 film from 82 to 12 A/min in poly isolation CMP process.

  3. 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.

  4. 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.

  5. Magnetic properties and tun-neling magnetoresistance in FeCo-SiO2 granular films

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Fefv(SiO2)1-fv granular films were fabricated by rf sputtering (fv represents the Fe volume fraction). The microstructure, magnetic properties as well as the tunneling magnetoresistance effect (TMR) were systematically studied. It was found that the maximum TMR ratio is about -3.3% at fv = 0.33. Under the same condition, a series of (Fe100-x Cox)0.33(SiO2)0.67 were prepared. TMR value reaches -4.5% at x = 53, while the microstructure of the film still keeps as that of Fe0.33(SiO2)0.67. The higher TMR ratio is con-tributed to the elevating of the spin polarization of particles. This is consistent with Inoue's theory.

  6. Photocatalytic degradation of glyphosate in water by N-doped SnO2/TiO2 thin-film-coated glass fibers.

    Science.gov (United States)

    Kongsong, Peerawas; Sikong, Lek; Niyomwas, Sutham; Rachpech, Vishnu

    2014-01-01

    Photocatalytic degradation of glyphosate contaminated in water was investigated. The N-doped SnO2/TiO2 films were prepared via sol-gel method, and coated on glass fibers by dipping method. The effects of nitrogen doping on coating morphology, physical properties and glyphosate degradation rates were experimentally determined. Main variable was the concentration of nitrogen doping in range 0-40 mol%. Nitrogen doping results in shifting the absorption wavelengths and narrowing the band gap energy those lead to enhancement of photocatalytic performance. The near optimal 20N/SnO2/TiO2 composite thin film exhibited about two- and four-folds of glyphosate degradation rates compared to the undoped SnO2/TiO2 and TiO2 films when photocatalytic treatment were performed under UV and solar irradiations, respectively, due to its narrowest band gap energy (optical absorption wavelength shifting to visible light region) and smallest crystallite size influenced by N-doping.

  7. 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.

  8. 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.

  9. Facile fabrication of hierarchical SnO(2) microspheres film on transparent FTO glass.

    Science.gov (United States)

    Wang, Yu-Fen; Lei, Bing-Xin; Hou, Yuan-Fang; Zhao, Wen-Xia; Liang, Chao-Lun; Su, Cheng-Yong; Kuang, Dai-Bin

    2010-02-15

    Hierarchical SnO(2) microspheres consisting of nanosheets on the fluorine-doped tin oxide (FTO) glass substrates are successfully prepared via a facile hydrothermal synthesis process. The as-prepared novel microsphere films were characterized in detail by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy. Moreover, SnO(2) nanoparticles with 30-80 nm in size covered on the surface of nanosheets/microspheres were also obtained by optimizing the hydrothermal reaction temperature, time, or volume ratio of acetylacetone/H(2)O. The detailed investigations disclose the experimental parameters, such as acetylacetone, NH(4)F, and seed layer play important roles in the morphology of hierarchical SnO(2) microspheres on the FTO glass. The formation process of SnO(2) microspheres is also proposed based on the observations of time dependent samples.

  10. Carbon dioxide and water adsorption on highly epitaxial Delafossite CuFeO2 thin film

    Science.gov (United States)

    Rojas, S.; Joshi, T.; Borisov, P.; Sarabia, M.; Lederman, D.; Cabrera, A. L.

    2015-03-01

    Thermal programmed desorption (TPD) of CO2 and H2O from a 200 nm thick CuFeO2 Delafossite surface was performed in a standard UHV chamber, The CuFeO2 thin film grown using Pulsed Laser Deposition (PLD) over an Al2O3 (0001) substrate with controlled O2 atmosphere resulted with highly epitaxial crystal structure. The adsorption/desorption of CO2 and H2O process was also monitored with X-ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES). Our results revealed that carbon dioxide interacts with CuFeO2 forming Fe carbonates compounds on its surface. Hydroxides were also formed on the surface due to water presence. Using TPD data, Arrhenius plots for CO2 and water desorption were done and activation energy for desorption was obtained. Funds FONDECyT 1130372; Thanks to P. Ferrari.

  11. Characterization of the SiO2 film deposited by using plasma enhanced chemical vapor deposition (PECVD with TEOS/N2/O2

    Directory of Open Access Journals (Sweden)

    Meysam Zarchi

    2013-12-01

    Full Text Available The purpose of this study was to examine how certain parameters like temperature, pressure, and gas composition affect the characteristics of SiO2 film by Plasma Enhanced Chemical Vapor Deposition (PECVD. We used of low temperature and an inductively coupled plasma (ICP for various with gas mixtures of TEOS/N2/O2 at a given RF power and dc bias voltage. For the gas mixture with 40 sccm of N2 in TEOS, 100 standard cubic centimeters per minute (sccm of N2, and 500 sccm of O2, transparent and scratch-resistant SiO2 could be deposited with a deposition rate of 30 nm/min when RF power of 500 W and a dc-bias voltage of 350V were applied. The characteristics of the deposited SiO2, such as the composition, the binding energy, etc. were compared with the SiO2 deposited by using thermal CVD and evaporation. It was found that the SiO2 deposited by PECVD with TEOS/N2/O2 exhibited properties typical of SiO2 deposited applying thermal CVD and evaporation. The surface roughness of the 100 nm-thick SiO2 deposited by PECVD was similar to that of the substrate.

  12. Effect of calcinations temperature on microstructures, photocatalytic activity and self-cleaning property of TiO2 and SnO2/TiO2 thin films prepared by sol-gel dip coating process

    Science.gov (United States)

    Sangchay, Weerachai

    2014-06-01

    The purpose of this research was to study the effect of calcinations temperature on phase transformation, crystallite size, morphology, photocatalytic activity and self-cleaning properties of TiO2 and SnO2/TiO2 thin films. The thin films were preparation by sol-gel dip coating process and calcinations at the temperature of 500 °C, 600 °C and 700 °C for 2 h with the heating rate of 10 °C/mim. The microstructures of the fabricated thin films were characterized by XRD and SEM techniques. The photocatalytic activity of the thin films was also tested via the degradation of methylene blue solution under UV irradiation. Finally, self-cleaning properties of thin films were evaluated by measuring the contact angle of water droplet on the thin films with and without UV irradiation. It was found that SnO2/TiO2 thin films calcinations at the temperature of 500 °C shows the highest of photocatalytic activity and self-cleaning properties.

  13. 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

  14. Enhanced antibacterial performance of hybrid semiconductor nanomaterials: ZnO/SnO 2 nanocomposite thin films

    Science.gov (United States)

    Talebian, Nasrin; Nilforoushan, Mohammad Reza; Zargar, Elahe Badri

    2011-10-01

    The nano-sized coupled oxides ZnO/SnO 2 thin films in a molar ratio of 2:1 (Z2S), 1:1 (ZS) and 1:2 (ZS2) were prepared using sol-gel dip coating method and characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-vis spectroscopy. Escherichia coli ( E. coli, ATCC 25922) was selected as a model for the Gram-negative bacteria to evaluate antibacterial property of composite samples compared with single ZnO (Z) and single SnO 2 (S) films. The antibacterial activity has been studied applying the so-called antibacterial drop test under UV illumination. The bactericidal activity was estimated by relative number of bacteria survived calculated from the number of viable cells which form colonies on the nutrient agar plates. The influence of the SnO 2-ZnO nanocomposite composition on the structural features and on the antibacterial properties of the thin films are reported and discussed. It is found that all coatings exhibited a high antibacterial activity. The coupled oxide photocatalyst Z2S has better photocatalytic activity to bacteria inactivation than ZS, ZS2, Z and S films. Furthermore, nanostructured films were active even in the absence of irradiation.

  15. 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.

  16. 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.

  17. Preparation of n-type semiconductor SnO2 thin films

    Institute of Scientific and Technical Information of China (English)

    Achour Rahal; Said Benramache; Boubaker Benhaoua

    2013-01-01

    We studied fluorine-doped tin oxide on a glass substrate at 350 ℃ using an ultrasonic spray technique.Tin (Ⅱ) chloride dehydrate,ammonium fluoride dehydrate,ethanol and NaOH were used as the starting material,dopant source,solvent and stabilizer,respectively.The SnO2:F thin films were deposited at 350 ℃ and a pending time of 60 and 90 s.The as-grown films exhibit a hexagonal wurtzite structure and have (101) orientation.The G =31.82 nm value of the grain size is attained from SnO2:F film grown at 90 s,and the transmittance is greater than 80% in the visible region.The optical gap energy is found to measure 4.05 eV for the film prepared at 90 s,and the increase in the electrical conductivity of the film with the temperature of the sample is up to a maximum value of 265.58 (Ω·cm)-1,with the maximum activation energy value of the films being found to measure 22.85 meV,indicating that the films exhibit an n-type semiconducting nature.

  18. Improved Treatment of Photothermal Cancer by Coating TiO2 on Porous Silicon.

    Science.gov (United States)

    Na, Kil Ju; Park, Gye-Choon

    2016-02-01

    In present society, the technology in various field has been sharply developed and advanced. In medical technology, especially, photothermal therapy and photodynamic therapy have had limelight for curing cancers and diseases. The study investigates the photothermal therapy that reduces side effects of existing cancer treatment, is applied to only cancer cells, and dose not harm any other normal cells. The photothermal properties of porous silicon for therapy are analyzed in order to destroy cancer cells that are more weak at heat than normal ones. For improving performance of porous silicon, it also analyzes the properties when irradiating the near infrared by heterologously junction TiO2 and TiO2NW, photocatalysts that are very stable and harmless to the environment and the human body, to porous silicon. Each sample of Si, PSi, TiO2/Psi, and TiO2NW/PSi was irradiated with 808 nm near-IR of 300, 500, and 700 mW/cm2 light intensity, where the maximum heating temperature was 43.8, 61.6, 67.9, and 61.9 degrees C at 300 mW/cm2; 54.1, 64.3, 78.8, and 68.9 degrees C at 500 mW/cm2; and 97.3, 102.8, 102.5, and 95 0C at 700 mW/cm2. The time required to reach the maximum temperature was less than 10 min for every case. The results indicate that TiO2/PSi thin film irradiated with a single near-infrared wavelength of 808 nm, which is known to have the best human permeability, offers the potential of being the most successful photothermal cancer therapy agent. It maximizes the photo-thermal characteristics within the shortest time, and minimizes the adverse effects on the human body.

  19. The effects of layering in ferroelectric Si-doped HfO2 thin films

    Science.gov (United States)

    Lomenzo, Patrick D.; Takmeel, Qanit; Zhou, Chuanzhen; Liu, Yang; Fancher, Chris M.; Jones, Jacob L.; Moghaddam, Saeed; Nishida, Toshikazu

    2014-08-01

    Atomic layer deposited Si-doped HfO2 thin films approximately 10 nm thick are deposited with various Si-dopant concentrations and distributions. The ferroelectric behavior of the HfO2 thin films are shown to be dependent on both the Si mol. % and the distribution of Si-dopants. Metal-ferroelectric-insulator-semiconductor capacitors are shown to exhibit a tunable remanent polarization through the adjustment of the Si-dopant distribution at a constant Si concentration. Inhomogeneous layering of Si-dopants within the thin films effectively lowers the remanent polarization. A pinched hysteresis loop is observed for higher Si-dopant concentrations and found to be dependent on the Si layering distribution.

  20. Chemically ordered face-centred tetragonal Fe–Pt nanoparticles embedded SiO2 films

    Indian Academy of Sciences (India)

    Sourav Pramanik; Goutam De

    2012-12-01

    Chemically ordered face-centred tetragonal (fct) Fe–Pt alloy nanoparticles (NPs) embedded SiO2 films were synthesized on glass substrate by in situ hybrid sol–gel approach followed by heating at 450–900 °C in air and reducing (10% H2–90% Ar) atmospheres. Heat treatment of Fe/Pt co-doped films in air caused generation of Pt NPs first. At this stage, Fe remained in ionic state covalently bonded with silica network. Further heat treatment at 800–900 °C in reducing atmosphere facilitated the formation of uniformly dispersed fct Fe–Pt alloy NPs in amorphous SiO2 film matrix. The generated alloy composition was estimated by grazing incidence X-ray diffraction and TEM analysis to be Fe0.42Pt0.58 which is close to the nominal value.

  1. Atmospheric Plasma Deposition of SiO2 Films for Adhesion Promoting Layers on Titanium

    Directory of Open Access Journals (Sweden)

    Liliana Kotte

    2014-12-01

    Full Text Available This paper evaluates the deposition of silica layers at atmospheric pressure as a pretreatment for the structural bonding of titanium (Ti6Al4V, Ti15V3Cr3Sn3Al in comparison to an anodizing process (NaTESi process. The SiO2 film was deposited using the LARGE plasma source, a linearly extended DC arc plasma source and applying hexamethyldisiloxane (HMDSO as a precursor. The morphology of the surface was analyzed by means of SEM, while the characterization of the chemical composition of deposited plasma layers was done by XPS and FTIR. The long-term durability of bonded samples was evaluated by means of a wedge test in hot/wet condition. The almost stoichiometric SiO2 film features a good long-term stability and a high bonding strength compared to the films produced with the wet-chemical NaTESi process.

  2. Effects of growth temperature on the properties of atomic layer deposition grown ZrO2 films

    Science.gov (United States)

    Scarel, G.; Ferrari, S.; Spiga, S.; Wiemer, C.; Tallarida, G.; Fanciulli, M.

    2003-07-01

    Zirconium dioxide films are grown in 200 atomic layer deposition cycles. Zirconium tetrachloride (ZrCl4) and water (H2O) are used as precursors. A relatively high dielectric constant (κ=22), wide band gap, and conduction band offset (5.8 and 1.4 eV, respectively) indicate that zirconium dioxide is a most promising substitute for silicon dioxide as a dielectric gate in complementary metal-oxide-semiconductor devices. However, crystallization and chlorine ions in the films might affect their electrical properties. These ions are produced during atomic layer deposition in which the ZrCl4 precursor reacts with the growth surface. It is desirable to tune the composition, morphology, and structural properties in order to improve their benefit on the electrical ones. To address this issue it is necessary to properly choose the growth parameters. This work focuses on the effects of the growth temperature Tg. ZrO2 films are grown at different substrate temperatures: 160, 200, 250, and 350 °C. Relevant modification of the film structure with a change in substrate temperature during growth is expected because the density of reactive sites [mainly Si+1-(OH)-1 bonds] decreases with an increase in temperature [Y. B. Kim et al., Electrochem. Solid-State Lett. 3, 346 (2000)]. The amorphous film component, for example, that develops at Si+1-(OH)-1 sites on the starting growth surface, is expected to decrease with an increase in growth temperature. The size and consequences of film property modifications with the growth temperature are investigated in this work using x-ray diffraction and reflectivity, and atomic force microscopy. Time of flight-secondary ion mass spectrometry is used to study contaminant species in the films. From capacitance-voltage (CV) and current-voltage (IV) measurements, respectively, the dielectric constant κZrO2 and the leakage current are studied as a function of the film growth temperature.

  3. Worm-like mesoporous TiO2 thin films templated using comb copolymer for dye-sensitized solar cells with polymer electrolyte

    Science.gov (United States)

    Lee, Jae Hun; Park, Cheol Hun; Jung, Jung Pyo; Kim, Jong Hak

    2015-12-01

    A comb copolymer consisting of hydrophobic poly(2-[3-(2H-benzotriazol-2-yl)-4-hydroxyphenyl] ethyl methacrylate) (PBEM) and hydrophilic poly(oxyethylene methacrylate) (POEM) is synthesized via one-pot free radical polymerization. The PBEM-POEM comb copolymer is used as an agent to direct the structure toward one consisting of worm-like mesoporous TiO2 (WM-TiO2) films. The selective, preferential interaction between the titania precursor and the hydrophilic POEM chains is responsible for the formation of a well-organized worm-like mesostructure. The morphology of the WM-TiO2 films is characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). In particular, the effects of film thickness on the optical and electrochemical properties are systematically investigated. The introduction of the WM-TiO2 layer between the nanocrystalline TiO2 (NC-TiO2) layer and fluorine-doped tin oxide (FTO) glass results in increased transmittance of visible light due to an antireflective property, decreased interfacial resistance and suppressed charge recombination at the interfaces of NC-TiO2/FTO glass. As a result, the photovoltaic conversion efficiency of the dye-sensitized solar cell (DSSC) with a polymer electrolyte is improved from 5.3% to 6.6% at an optimum film thickness (310 nm). The obtained efficiency represents a higher efficiency for the N719-based DSSC with a solvent-free, polymer electrolyte.

  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. 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.

  6. Enhanced surface activity of SnO2 thin film verified